Partial Correlation-Based Retinotopically Organized Resting-State Functional Connectivity Within and Between Areas of the Visual Cortex Reflects More Than Cortical Distance.

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Dawson, Debra Ann; Lam, Jack; Lewis, Lindsay B; Carbonell, Felix; Mendola, Janine D; Shmuel, Amir

2016-02-01

approximately linearly with increasing distances separating the tested ROIs. Partial correlation showed a more complex dependence on cortical distance: it decreased exponentially with increasing distance within a quadrant, but was best fit by a quadratic function between quadrants. We conclude that RSFCs within and between lower visual areas are retinotopically organized. Correlation-based FC is nonselectively high across lower visual areas, even between regions that do not share direct anatomical connections. The mechanisms likely involve network effects caused by the dense anatomical connectivity within this network and projections from higher visual areas. FC based on partial correlation, which minimizes network effects, follows expectations based on direct anatomical connections in the monkey visual cortex better than correlation. Last, partial correlation-based retinotopically organized RSFC reflects more than cortical distance effects.

Is the ipsilateral cortex surrounding the lesion or the non-injured contralateral cortex important for motor recovery in rats with photochemically induced cortical lesions?

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Takata, Kotaro; Yamauchi, Hideki; Tatsuno, Hisashi; Hashimoto, Keiji; Abo, Masahiro

2006-01-01

To determine whether the ipsilateral cortex surrounding the lesion or the non-injured contralateral cortex is important for motor recovery after brain damage in the photochemically initiated thrombosis (PIT) model. We induced PIT in the sensorimotor cortex in rats and examined the recovery of motor function using the beam-walking test. In 24 rats, the right sensorimotor cortex was lesioned after 2 days of training for the beam-walking test (group 1). After 10 days, PIT was induced in the left sensorimotor cortex. Eight additional rats (group 2) received 2 days training in beam walking, then underwent the beam-walking test to evaluate function. After 10 days of testing, the left sensorimotor cortex was lesioned and recovery was monitored by the beam-walking test for 8 days. In group 1 animals, left hindlimb function caused by a right sensorimotor cortex lesion recovered within 10 days after the operation. Right hindlimb function caused by the left-side lesion recovered within 6 days. In group 2, right hindlimb function caused by induction of the left-side lesion after a total of 12 days of beam-walking training and testing recovered within 6 days as with the double PIT model. The training effect may be relevant to reorganization and neuromodulation. Motor recovery patterns did not indicate whether motor recovery was dependent on the ipsilateral cortex surrounding the lesion or the cortex of the contralateral side. The results emphasize the need for selection of appropriate programs tailored to the area of cortical damage in order to enhance motor functional recovery in this model. Copyright 2006 S. Karger AG, Basel.

Spatial specificity of working memory representations in the early visual cortex.

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Pratte, Michael S; Tong, Frank

2014-03-19

Recent fMRI decoding studies have demonstrated that early retinotopic visual areas exhibit similar patterns of activity during the perception of a stimulus and during the maintenance of that stimulus in working memory. These findings provide support for the sensory recruitment hypothesis that the mechanisms underlying perception serve as a foundation for visual working memory. However, a recent study by Ester, Serences, and Awh (2009) found that the orientation of a peripheral grating maintained in working memory could be classified from both the contralateral and ipsilateral regions of the primary visual cortex (V1), implying that, unlike perception, feature-specific information was maintained in a nonretinotopic manner. Here, we evaluated the hypothesis that early visual areas can maintain information in a spatially specific manner and will do so if the task encourages the binding of feature information to a specific location. To encourage reliance on spatially specific memory, our experiment required observers to retain the orientations of two laterally presented gratings. Multivariate pattern analysis revealed that the orientation of each remembered grating was classified more accurately based on activity patterns in the contralateral than in the ipsilateral regions of V1 and V2. In contrast, higher extrastriate areas exhibited similar levels of performance across the two hemispheres. A time-resolved analysis further indicated that the retinotopic specificity of the working memory representation in V1 and V2 was maintained throughout the retention interval. Our results suggest that early visual areas provide a cortical basis for actively maintaining information about the features and locations of stimuli in visual working memory.

Proteomic analysis of trans-hemispheric motor cortex reorganization following contralateral C7 nerve transfer

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Yuan, Yin; Xu, Xiu-yue; Lao, Jie; Zhao, Xin

2018-01-01

Nerve transfer is the most common treatment for total brachial plexus avulsion injury. After nerve transfer, the movement of the injured limb may be activated by certain movements of the healthy limb at the early stage of recovery, i.e., trans-hemispheric reorganization. Previous studies have focused on functional magnetic resonance imaging and changes in brain-derived neurotrophic factor and growth associated protein 43, but there have been no proteomics studies. In this study, we designed a rat model of total brachial plexus avulsion injury involving contralateral C7 nerve transfer. Isobaric tags for relative and absolute quantitation and western blot assay were then used to screen differentially expressed proteins in bilateral motor cortices. We found that most differentially expressed proteins in both cortices of upper limb were associated with nervous system development and function (including neuron differentiation and development, axonogenesis, and guidance), microtubule and cytoskeleton organization, synapse plasticity, and transmission of nerve impulses. Two key differentially expressed proteins, neurofilament light (NFL) and Thy-1, were identified. In contralateral cortex, the NFL level was upregulated 2 weeks after transfer and downregulated at 1 and 5 months. The Thy-1 level was upregulated from 1 to 5 months. In the affected cortex, the NFL level increased gradually from 1 to 5 months. Western blot results of key differentially expressed proteins were consistent with the proteomic findings. These results indicate that NFL and Thy-1 play an important role in trans-hemispheric organization following total brachial plexus root avulsion and contralateral C7 nerve transfer. PMID:29557385

Contralateral white noise selectively changes left human auditory cortex activity in a lexical decision task.

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Behne, Nicole; Wendt, Beate; Scheich, Henning; Brechmann, André

2006-04-01

In a previous study, we hypothesized that the approach of presenting information-bearing stimuli to one ear and noise to the other ear may be a general strategy to determine hemispheric specialization in auditory cortex (AC). In that study, we confirmed the dominant role of the right AC in directional categorization of frequency modulations by showing that fMRI activation of right but not left AC was sharply emphasized when masking noise was presented to the contralateral ear. Here, we tested this hypothesis using a lexical decision task supposed to be mainly processed in the left hemisphere. Subjects had to distinguish between pseudowords and natural words presented monaurally to the left or right ear either with or without white noise to the other ear. According to our hypothesis, we expected a strong effect of contralateral noise on fMRI activity in left AC. For the control conditions without noise, we found that activation in both auditory cortices was stronger on contralateral than on ipsilateral word stimulation consistent with a more influential contralateral than ipsilateral auditory pathway. Additional presentation of contralateral noise did not significantly change activation in right AC, whereas it led to a significant increase of activation in left AC compared with the condition without noise. This is consistent with a left hemispheric specialization for lexical decisions. Thus our results support the hypothesis that activation by ipsilateral information-bearing stimuli is upregulated mainly in the hemisphere specialized for a given task when noise is presented to the more influential contralateral ear.

Reorganization of retinotopic maps after occipital lobe infarction.

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Vaina, Lucia M; Soloviev, Sergei; Calabro, Finnegan J; Buonanno, Ferdinando; Passingham, Richard; Cowey, Alan

2014-06-01

We studied patient JS, who had a right occipital infarct that encroached on visual areas V1, V2v, and VP. When tested psychophysically, he was very impaired at detecting the direction of motion in random dot displays where a variable proportion of dots moving in one direction (signal) were embedded in masking motion noise (noise dots). The impairment on this motion coherence task was especially marked when the display was presented to the upper left (affected) visual quadrant, contralateral to his lesion. However, with extensive training, by 11 months his threshold fell to the level of healthy participants. Training on the motion coherence task generalized to another motion task, the motion discontinuity task, on which he had to detect the presence of an edge that was defined by the difference in the direction of the coherently moving dots (signal) within the display. He was much better at this task at 8 than 3 months, and this improvement was associated with an increase in the activation of the human MT complex (hMT(+)) and in the kinetic occipital region as shown by repeated fMRI scans. We also used fMRI to perform retinotopic mapping at 3, 8, and 11 months after the infarct. We quantified the retinotopy and areal shifts by measuring the distances between the center of mass of functionally defined areas, computed in spherical surface-based coordinates. The functionally defined retinotopic areas V1, V2v, V2d, and VP were initially smaller in the lesioned right hemisphere, but they increased in size between 3 and 11 months. This change was not found in the normal, left hemisphere of the patient or in either hemispheres of the healthy control participants. We were interested in whether practice on the motion coherence task promoted the changes in the retinotopic maps. We compared the results for patient JS with those from another patient (PF) who had a comparable lesion but had not been given such practice. We found similar changes in the maps in the lesioned

Neural associations of the early retinotopic cortex with the lateral occipital complex during visual perception.

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Delong Zhang

Full Text Available Previous studies have demonstrated that the early retinotopic cortex (ERC, i.e., V1/V2/V3 is highly associated with the lateral occipital complex (LOC during visual perception. However, it remains largely unclear how to evaluate their associations in quantitative way. The present study tried to apply a multivariate pattern analysis (MVPA to quantify the neural activity in ERC and its association with that of the LOC when participants saw visual images. To this end, we assessed whether low-level visual features (Gabor features could predict the neural activity in the ERC and LOC according to a voxel-based encoding model (VBEM, and then quantified the association of the neural activity between these regions by using an analogical VBEM. We found that the Gabor features remarkably predicted the activity of the ERC (e.g., the predicted accuracy was 52.5% for a participant instead of that of the LOC (4.2%. Moreover, the MVPA approach can also be used to establish corresponding relationships between the activity patterns in the LOC and those in the ERC (64.2%. In particular, we found that the integration of the Gabor features and LOC visual information could dramatically improve the 'prediction' of ERC activity (88.3%. Overall, the present study provides new evidences for the possibility of quantifying the association of the neural activity between the regions of ERC and LOC. This approach will help to provide further insights into the neural substrates of the visual processing.

Topographic contribution of early visual cortex to short-term memory consolidation: a transcranial magnetic stimulation study.

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van de Ven, Vincent; Jacobs, Christianne; Sack, Alexander T

2012-01-04

The neural correlates for retention of visual information in visual short-term memory are considered separate from those of sensory encoding. However, recent findings suggest that sensory areas may play a role also in short-term memory. We investigated the functional relevance, spatial specificity, and temporal characteristics of human early visual cortex in the consolidation of capacity-limited topographic visual memory using transcranial magnetic stimulation (TMS). Topographically specific TMS pulses were delivered over lateralized occipital cortex at 100, 200, or 400 ms into the retention phase of a modified change detection task with low or high memory loads. For the high but not the low memory load, we found decreased memory performance for memory trials in the visual field contralateral, but not ipsilateral to the side of TMS, when pulses were delivered at 200 ms into the retention interval. A behavioral version of the TMS experiment, in which a distractor stimulus (memory mask) replaced the TMS pulses, further corroborated these findings. Our findings suggest that retinotopic visual cortex contributes to the short-term consolidation of topographic visual memory during early stages of the retention of visual information. Further, TMS-induced interference decreased the strength (amplitude) of the memory representation, which most strongly affected the high memory load trials.

Multishot versus single-shot pulse sequences in very high field fMRI: a comparison using retinotopic mapping.

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Jascha D Swisher

Full Text Available High-resolution functional MRI is a leading application for very high field (7 Tesla human MR imaging. Though higher field strengths promise improvements in signal-to-noise ratios (SNR and BOLD contrast relative to fMRI at 3 Tesla, these benefits may be partially offset by accompanying increases in geometric distortion and other off-resonance effects. Such effects may be especially pronounced with the single-shot EPI pulse sequences typically used for fMRI at standard field strengths. As an alternative, one might consider multishot pulse sequences, which may lead to somewhat lower temporal SNR than standard EPI, but which are also often substantially less susceptible to off-resonance effects. Here we consider retinotopic mapping of human visual cortex as a practical test case by which to compare examples of these sequence types for high-resolution fMRI at 7 Tesla. We performed polar angle retinotopic mapping at each of 3 isotropic resolutions (2.0, 1.7, and 1.1 mm using both accelerated single-shot 2D EPI and accelerated multishot 3D gradient-echo pulse sequences. We found that single-shot EPI indeed led to greater temporal SNR and contrast-to-noise ratios (CNR than the multishot sequences. However, additional distortion correction in postprocessing was required in order to fully realize these advantages, particularly at higher resolutions. The retinotopic maps produced by both sequence types were qualitatively comparable, and showed equivalent test/retest reliability. Thus, when surface-based analyses are planned, or in other circumstances where geometric distortion is of particular concern, multishot pulse sequences could provide a viable alternative to single-shot EPI.

Frontoparietal regions may become hypoactive after intermittent theta burst stimulation over the contralateral homologous cortex in humans.

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He, Xiaofei; Lan, Yue; Xu, Guangqing; Mao, Yurong; Chen, Zhenghong; Huang, Dongfeng; Pei, Zhong

2013-12-01

Brain injury to the dorsal frontoparietal networks, including the posterior parietal cortex (PPC) and dorsolateral prefrontal cortex (DLPFC), commonly cause spatial neglect. However, the interaction of these different regions in spatial attention is unclear. The aim of the present study was to investigate whether hyperexcitable neural networks can cause an abnormal interhemispheric inhibition. The Attention Network Test was used to test subjects following intermittent theta burst stimulation (iTBS) to the left or right frontoparietal networks. During the Attention Network Test task, all subjects tolerated each conditioning iTBS without any obvious iTBS-related side effects. Subjects receiving real-right-PPC iTBS showed significant enhancement in both alerting and orienting efficiency compared with those receiving either sham-right-PPC iTBS or real-left-PPC iTBS. Moreover, subjects exposed to the real-right-DLPFC iTBS exhibited significant improvement in both alerting and executive control efficiency, compared with those exposed to either the sham-right-DLPFC or real-left-DLPFC conditioning. Interestingly, compared with subjects exposed to the sham-left-PPC stimuli, subjects exposed to the real-left-PPC iTBS had a significant deficit in the orienting index. The present study indicates that iTBS over the contralateral homologous cortex may induce the hypoactivity of the right PPC through interhemispheric competition in spatial orienting attention.

Large-scale remapping of visual cortex is absent in adult humans with macular degeneration

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Baseler, Heidi A.; Gouws, Andre; Haak, Koen V.; Racey, Christopher; Crossland, Michael D.; Tufail, Adnan; Rubin, Gary S.; Cornelissen, Frans W.; Morland, Antony B.

The occipital lobe contains retinotopic representations of the visual field. The representation of the central retina in early visual areas (V1-3) is found at the occipital pole. When the central retina is lesioned in both eyes by macular degeneration, this region of visual cortex at the occipital

Different functional reorganization of motor cortex after transfer of the contralateral C7 to different recipient nerves in young rats with total brachial plexus root avulsion.

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Pan, Feng; Wei, Hai-feng; Chen, Liang; Gu, Yu-dong

2012-12-07

Clinically, contralateral C7 transfer is used for nerve reconstruction in brachial plexus injuries. Postoperatively, synchronous motions at the donor limb are noteworthy. This study studied if different recipient nerves influenced transhemispheric functional reorganization of motor cortex after this procedure. 90 young rats with total root avulsion of the brachial plexus were divided into groups 1-3 of contralateral C7 transfer to anterior division of the upper trunk, to both the musculocutaneous and median nerves, and to the median nerve, respectively. After reinnervation of target muscles, number of sites for forelimb representations in bilateral motor cortices was determined by intracortical microstimulation at 1.5, 3, 6, 9, and 12 months postoperatively. At nine months, transhemispheric reorganization of nerves neurotized by contralateral C7 was fulfilled in four of six rats in group 1, one of six in group 2 and none in group 3, respectively; at 12 months, that was fulfilled in five of six in group 1, four of six in groups 2 and 3, respectively. Logistic regression analysis showed that rate of fulfilled transhemispheric reorganization in group 1 was 12.19 times that in group 3 (95% CI 0.006-0.651, p=0.032). At 12 months, number of sites for hindlimb representations which had encroached upon original forelimb representations on the uninjured side was statistically more in group 3 than in group 2 (t=9.5, pmotor cortex than that to median nerve alone in rats. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Reduced contralateral hemispheric flow measured by SPECT in cerebellar lesions

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Soenmezoglu, K.; Sperling, B.; Lassen, N.A.; Henriksen, T.; Tfelt-Hansen, P.

1993-01-01

Four patients with clinical signs of cerebellar stroke were studied twice by SPECT using 99m Tc-HMPAO as a tracer for cerebral blood flow (CBF). When first scanned 6 to 22 days after onset, all had a region of very low CBF in the symptomatic cerebellar hemisphere, and a mild to moderate CBF reduction (average 10%) in contralateral hemispheric cortex. In all four cases clinical signs of unilateral cerebellar dysfunction were still present when rescanned 1 to 4 months later and the relative CBF decrease in the contralateral cortex of the forebrain also remained. The basal ganglia contralateral to the cerebellar lesion CBF showed variable alterations. A relative CBF decrease was seen in upper part of basal ganglia in all four cases, but it was not a constant phenomenon. A relative CBF increase in both early and late SPECT scans was seen at low levels of neostriatum in two cases. The remote CBF changes in cerebellar stroke seen in the forebrain are probably caused by reduced or abolished cerebellar output. The term ''Crossed Cerebral Diaschisis'' may be used to describe these CBF changes that would appear to reflect both decreased and increased neuronal activity. (au)

Auditory attention activates peripheral visual cortex.

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Anthony D Cate

Full Text Available BACKGROUND: Recent neuroimaging studies have revealed that putatively unimodal regions of visual cortex can be activated during auditory tasks in sighted as well as in blind subjects. However, the task determinants and functional significance of auditory occipital activations (AOAs remains unclear. METHODOLOGY/PRINCIPAL FINDINGS: We examined AOAs in an intermodal selective attention task to distinguish whether they were stimulus-bound or recruited by higher-level cognitive operations associated with auditory attention. Cortical surface mapping showed that auditory occipital activations were localized to retinotopic visual cortex subserving the far peripheral visual field. AOAs depended strictly on the sustained engagement of auditory attention and were enhanced in more difficult listening conditions. In contrast, unattended sounds produced no AOAs regardless of their intensity, spatial location, or frequency. CONCLUSIONS/SIGNIFICANCE: Auditory attention, but not passive exposure to sounds, routinely activated peripheral regions of visual cortex when subjects attended to sound sources outside the visual field. Functional connections between auditory cortex and visual cortex subserving the peripheral visual field appear to underlie the generation of AOAs, which may reflect the priming of visual regions to process soon-to-appear objects associated with unseen sound sources.

Contralateral Noise Stimulation Delays P300 Latency in School-Aged Children.

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Ubiali, Thalita; Sanfins, Milaine Dominici; Borges, Leticia Reis; Colella-Santos, Maria Francisca

2016-01-01

The auditory cortex modulates auditory afferents through the olivocochlear system, which innervates the outer hair cells and the afferent neurons under the inner hair cells in the cochlea. Most of the studies that investigated the efferent activity in humans focused on evaluating the suppression of the otoacoustic emissions by stimulating the contralateral ear with noise, which assesses the activation of the medial olivocochlear bundle. The neurophysiology and the mechanisms involving efferent activity on higher regions of the auditory pathway, however, are still unknown. Also, the lack of studies investigating the effects of noise on human auditory cortex, especially in peadiatric population, points to the need for recording the late auditory potentials in noise conditions. Assessing the auditory efferents in schoolaged children is highly important due to some of its attributed functions such as selective attention and signal detection in noise, which are important abilities related to the development of language and academic skills. For this reason, the aim of the present study was to evaluate the effects of noise on P300 responses of children with normal hearing. P300 was recorded in 27 children aged from 8 to 14 years with normal hearing in two conditions: with and whitout contralateral white noise stimulation. P300 latencies were significantly longer at the presence of contralateral noise. No significant changes were observed for the amplitude values. Contralateral white noise stimulation delayed P300 latency in a group of school-aged children with normal hearing. These results suggest a possible influence of the medial olivocochlear activation on P300 responses under noise condition.

Quantitative evaluation of fMRI retinotopic maps, from V1 to V4, for cognitive experiments

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Cecile eBordier

2015-05-01

Full Text Available FMRI retinotopic mapping is a non-invasive technique for the delineation of low-level visual areas in individual subjects. It generally relies upon the analysis of functional responses to periodic visual stimuli that encode eccentricity or polar angle in the visual field. This technique is used in vision research when the precise assignation of brain activation to retinotopic areas is an issue. It involves processing steps computed with different algorithms and embedded in various software suites. Manual intervention may be needed for some steps. Although the diversity of the available processing suites and manual interventions may potentially introduce some differences in the final delineation of visual areas, no documented comparison between maps obtained with different procedures has been reported in the literature. To explore the effect of the processing steps on the quality of the maps obtained, we used two tools, BALC, which relies on a fully automated procedure, and BrainVoyager, where areas are delineated by hand on the brain surface. To focus on the mapping procedures specifically, we used the same SPM pipeline for pretreatment and the same tissue segmentation tool. We document the consistency and differences of the fMRI retinotopic maps obtained from routine retinotopy experiments on ten subjects. The maps obtained by skilled users are never fully identical. However, the agreement between the maps, around 80% for low-level areas, is probably sufficient for most applications. Our results also indicate that assigning cognitive activations, following a specific experiment (here, color perception, to individual retinotopic maps is not free of errors. We provide measurements of this error, that may help for the cautious interpretation of cognitive activation projection onto fMRI retinotopic maps. On average, the magnitude of the error is about 20%, with much larger differences in a few subjects.

Contralateral Noise Stimulation Delays P300 Latency in School-Aged Children.

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Thalita Ubiali

Full Text Available The auditory cortex modulates auditory afferents through the olivocochlear system, which innervates the outer hair cells and the afferent neurons under the inner hair cells in the cochlea. Most of the studies that investigated the efferent activity in humans focused on evaluating the suppression of the otoacoustic emissions by stimulating the contralateral ear with noise, which assesses the activation of the medial olivocochlear bundle. The neurophysiology and the mechanisms involving efferent activity on higher regions of the auditory pathway, however, are still unknown. Also, the lack of studies investigating the effects of noise on human auditory cortex, especially in peadiatric population, points to the need for recording the late auditory potentials in noise conditions. Assessing the auditory efferents in schoolaged children is highly important due to some of its attributed functions such as selective attention and signal detection in noise, which are important abilities related to the development of language and academic skills. For this reason, the aim of the present study was to evaluate the effects of noise on P300 responses of children with normal hearing.P300 was recorded in 27 children aged from 8 to 14 years with normal hearing in two conditions: with and whitout contralateral white noise stimulation.P300 latencies were significantly longer at the presence of contralateral noise. No significant changes were observed for the amplitude values.Contralateral white noise stimulation delayed P300 latency in a group of school-aged children with normal hearing. These results suggest a possible influence of the medial olivocochlear activation on P300 responses under noise condition.

Hemispheric differences in electrical and hemodynamic responses during hemifield visual stimulation with graded contrasts.

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Si, Juanning; Zhang, Xin; Zhang, Yujin; Jiang, Tianzi

2017-04-01

A multimodal neuroimaging technique based on electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS) was used with horizontal hemifield visual stimuli with graded contrasts to investigate the retinotopic mapping more fully as well as to explore hemispheric differences in neuronal activity, the hemodynamic response, and the neurovascular coupling relationship in the visual cortex. The fNIRS results showed the expected activation over the contralateral hemisphere for both the left and right hemifield visual stimulations. However, the EEG results presented a paradoxical lateralization, with the maximal response located over the ipsilateral hemisphere but with the polarity inversed components located over the contralateral hemisphere. Our results suggest that the polarity inversion as well as the latency advantage over the contralateral hemisphere cause the amplitude of the VEP over the contralateral hemisphere to be smaller than that over the ipsilateral hemisphere. Both the neuronal and hemodynamic responses changed logarithmically with the level of contrast in the hemifield visual stimulations. Moreover, the amplitudes and latencies of the visual evoked potentials (VEPs) were linearly correlated with the hemodynamic responses despite differences in the slopes.

Saturation in Phosphene Size with Increasing Current Levels Delivered to Human Visual Cortex.

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Bosking, William H; Sun, Ping; Ozker, Muge; Pei, Xiaomei; Foster, Brett L; Beauchamp, Michael S; Yoshor, Daniel

2017-07-26

Electrically stimulating early visual cortex results in a visual percept known as a phosphene. Although phosphenes can be evoked by a wide range of electrode sizes and current amplitudes, they are invariably described as small. To better understand this observation, we electrically stimulated 93 electrodes implanted in the visual cortex of 13 human subjects who reported phosphene size while stimulation current was varied. Phosphene size increased as the stimulation current was initially raised above threshold, but then rapidly reached saturation. Phosphene size also depended on the location of the stimulated site, with size increasing with distance from the foveal representation. We developed a model relating phosphene size to the amount of activated cortex and its location within the retinotopic map. First, a sigmoidal curve was used to predict the amount of activated cortex at a given current. Second, the amount of active cortex was converted to degrees of visual angle by multiplying by the inverse cortical magnification factor for that retinotopic location. This simple model accurately predicted phosphene size for a broad range of stimulation currents and cortical locations. The unexpected saturation in phosphene sizes suggests that the functional architecture of cerebral cortex may impose fundamental restrictions on the spread of artificially evoked activity and this may be an important consideration in the design of cortical prosthetic devices. SIGNIFICANCE STATEMENT Understanding the neural basis for phosphenes, the visual percepts created by electrical stimulation of visual cortex, is fundamental to the development of a visual cortical prosthetic. Our experiments in human subjects implanted with electrodes over visual cortex show that it is the activity of a large population of cells spread out across several millimeters of tissue that supports the perception of a phosphene. In addition, we describe an important feature of the production of phosphenes by

Gradual remapping results in early retinotopic and late spatiotopic inhibition of return.

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Mathôt, S.; Theeuwes, J.

2010-01-01

Here we report that immediately following the execution of an eye movement, oculomotor inhibition of return resides in retinotopic (eye-centered) coordinates. At longer postsaccadic intervals, inhibition resides in spatiotopic (world-centered) coordinates. These results are explained in terms of

Use-dependent dendritic regrowth is limited after unilateral controlled cortical impact to the forelimb sensorimotor cortex.

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Jones, Theresa A; Liput, Daniel J; Maresh, Erin L; Donlan, Nicole; Parikh, Toral J; Marlowe, Dana; Kozlowski, Dorothy A

2012-05-01

Compensatory neural plasticity occurs in both hemispheres following unilateral cortical damage incurred by seizures, stroke, and focal lesions. Plasticity is thought to play a role in recovery of function, and is important for the utility of rehabilitation strategies. Such effects have not been well described in models of traumatic brain injury (TBI). We examined changes in immunoreactivity for neural structural and plasticity-relevant proteins in the area surrounding a controlled cortical impact (CCI) to the forelimb sensorimotor cortex (FL-SMC), and in the contralateral homotopic cortex over time (3-28 days). CCI resulted in considerable motor deficits in the forelimb contralateral to injury, and increased reliance on the ipsilateral forelimb. The density of dendritic processes, visualized with immunostaining for microtubule-associated protein-2 (MAP-2), were bilaterally decreased at all time points. Synaptophysin (SYN) immunoreactivity increased transiently in the injured hemisphere, but this reflected an atypical labeling pattern, and it was unchanged in the contralateral hemisphere compared to uninjured controls. The lack of compensatory neuronal structural plasticity in the contralateral homotopic cortex, despite behavioral asymmetries, is in contrast to previous findings in stroke models. In the cortex surrounding the injury (but not the contralateral cortex), decreases in dendrites were accompanied by neurodegeneration, as indicated by Fluoro-Jade B (FJB) staining, and increased expression of the growth-inhibitory protein Nogo-A. These studies indicate that, following unilateral CCI, the cortex undergoes neuronal structural degradation in both hemispheres out to 28 days post-injury, which may be indicative of compromised compensatory plasticity. This is likely to be an important consideration in designing therapeutic strategies aimed at enhancing plasticity following TBI.

Non-retinotopic motor-visual recalibration to temporal lag

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Masaki eTsujita

2012-11-01

Full Text Available Temporal order judgment between the voluntary motor action and its perceptual feedback is important in distinguishing between a sensory feedback which is caused by observer’s own action and other stimulus, which are irrelevant to that action. Prolonged exposure to fixed temporal lag between motor action and visual feedback recalibrates motor-visual temporal relationship, and consequently shifts the point of subjective simultaneity (PSS. Previous studies on the audio-visual temporal recalibration without voluntary action revealed that both low and high level processing are involved. However, it is not clear how the low and high level processings affect the recalibration to constant temporal lag between voluntary action and visual feedback. This study examined retinotopic specificity of the motor-visual temporal recalibration. During the adaptation phase, observers repeatedly pressed a key, and visual stimulus was presented in left or right visual field with a fixed temporal lag (0 or 200 ms. In the test phase, observers performed a temporal order judgment for observer’s voluntary keypress and test stimulus, which was presented in the same as or opposite to the visual field in which the stimulus was presented in the adaptation phase. We found that the PSS was shifted toward the exposed lag in both visual fields. These results suggest that the low visual processing, which is retinotopically specific, has minor contribution to the multimodal adaptation, and that the adaptation to shift the PSS mainly depends upon the high level processing such as attention to specific properties of the stimulus.

Behavioral Consequences of a Bifacial Map in the Mouse Somatosensory Cortex.

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Tsytsarev, Vassiliy; Arakawa, Hiroyuki; Zhao, Shuxin; Chédotal, Alain; Erzurumlu, Reha S

2017-07-26

The whisker system is an important sensory organ with extensive neural representations in the brain of the mouse. Patterned neural modules (barrelettes) in the ipsilateral principal sensory nucleus of the trigeminal nerve (PrV) correspond to the whiskers. Axons of the PrV barrelette neurons cross the midline and confer the whisker-related patterning to the contralateral ventroposteromedial nucleus of the thalamus, and subsequently to the cortex. In this way, specific neural modules called barreloids and barrels in the contralateral thalamus and cortex represent each whisker. Partial midline crossing of the PrV axons, in a conditional Robo3 mutant ( Robo3 R3-5 cKO ) mouse line, leads to the formation of bilateral whisker maps in the ventroposteromedial, as well as the barrel cortex. We used voltage-sensitive dye optical imaging and somatosensory and motor behavioral tests to characterize the consequences of bifacial maps in the thalamocortical system. Voltage-sensitive dye optical imaging verified functional, bilateral whisker representation in the barrel cortex and activation of distinct cortical loci following ipsilateral and contralateral stimulation of the specific whiskers. The mutant animals were comparable with the control animals in sensorimotor tests. However, they showed noticeable deficits in all of the whisker-dependent or -related tests, including Y-maze exploration, horizontal surface approach, bridge crossing, gap crossing, texture discrimination, floating in water, and whisking laterality. Our results indicate that bifacial maps along the thalamocortical system do not offer a functional advantage. Instead, they lead to impairments, possibly due to the smaller size of the whisker-related modules and interference between the ipsilateral and contralateral whisker representations in the same thalamus and cortex. SIGNIFICANCE STATEMENT The whisker sensory system plays a quintessentially important role in exploratory behavior of mice and other nocturnal

Imaging the spatio-temporal dynamics of supragranular activity in the rat somatosensory cortex in response to stimulation of the paws.

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M L Morales-Botello

Full Text Available We employed voltage-sensitive dye (VSD imaging to investigate the spatio-temporal dynamics of the responses of the supragranular somatosensory cortex to stimulation of the four paws in urethane-anesthetized rats. We obtained the following main results. (1 Stimulation of the contralateral forepaw evoked VSD responses with greater amplitude and smaller latency than stimulation of the contralateral hindpaw, and ipsilateral VSD responses had a lower amplitude and greater latency than contralateral responses. (2 While the contralateral stimulation initially activated only one focus, the ipsilateral stimulation initially activated two foci: one focus was typically medial to the focus activated by contralateral stimulation and was stereotaxically localized in the motor cortex; the other focus was typically posterior to the focus activated by contralateral stimulation and was stereotaxically localized in the somatosensory cortex. (3 Forepaw and hindpaw somatosensory stimuli activated large areas of the sensorimotor cortex, well beyond the forepaw and hindpaw somatosensory areas of classical somatotopic maps, and forepaw stimuli activated larger cortical areas with greater activation velocity than hindpaw stimuli. (4 Stimulation of the forepaw and hindpaw evoked different cortical activation dynamics: forepaw responses displayed a clear medial directionality, whereas hindpaw responses were much more uniform in all directions. In conclusion, this work offers a complete spatio-temporal map of the supragranular VSD cortical activation in response to stimulation of the paws, showing important somatotopic differences between contralateral and ipsilateral maps as well as differences in the spatio-temporal activation dynamics in response to forepaw and hindpaw stimuli.

Classification of Real and Imagined Sounds in Early Visual Cortex

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Petra Vetter

2011-10-01

Full Text Available Early visual cortex has been thought to be mainly involved in the detection of low-level visual features. Here we show that complex natural sounds can be decoded from early visual cortex activity, in the absence of visual stimulation and both when sounds are actually displayed and when they are merely imagined. Blindfolded subjects listened to three complex natural sounds (bird singing, people talking, traffic noise; Exp. 1 or received word cues (“forest”, “people”, “traffic”; Exp 2 to imagine the associated scene. fMRI BOLD activation patterns from retinotopically defined early visual areas were fed into a multivariate pattern classification algorithm (a linear support vector machine. Actual sounds were discriminated above chance in V2 and V3 and imagined sounds were decoded in V1. Also cross-classification, ie, training the classifier to real sounds and testing it to imagined sounds and vice versa, was successful. Two further experiments showed that an orthogonal working memory task does not interfere with sound classification in early visual cortex (Exp. 3, however, an orthogonal visuo-spatial imagery task does (Exp. 4. These results demonstrate that early visual cortex activity contains content-specific information from hearing and from imagery, challenging the view of a strict modality-specific function of early visual cortex.

Fetal frontal cortex transplant (14C) 2-deoxyglucose uptake and histology: survival in cavities of host rat brain motor cortex

International Nuclear Information System (INIS)

Sharp, F.R.; Gonzalez, M.F.

1984-01-01

Fetal frontal neocortex from 18-day-old rat embryonic brain was transplanted into cavities in 30-day-old host motor cortex. Sixty days after transplantation, 5 of 15 transplanted rats had surviving fetal transplants. The fetal cortex transplants were physically attached to the host brain, completely filled the original cavity, and had numerous surviving cells including pyramidal neurons. Cell lamination within the fetal transplant was abnormal. The ( 14 C) 2-deoxyglucose uptake of all five of the fetal neocortex transplants was less than adjacent cortex and contralateral host motor-sensory cortex, but more than adjacent corpus callosum white matter. The results indicate that fetal frontal neocortex can be transplanted into damaged rat motor cortex. The metabolic rate of the transplants suggests they could be partially functional

[Transcranial magnetic stimulation and motor cortex stimulation in neuropathic pain].

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Mylius, V; Ayache, S S; Teepker, M; Kappus, C; Kolodziej, M; Rosenow, F; Nimsky, C; Oertel, W H; Lefaucheur, J P

2012-12-01

Non-invasive and invasive cortical stimulation allows the modulation of therapy-refractory neuropathic pain. High-frequency repetitive transcranial magnetic stimulation (rTMS) of the contralateral motor cortex yields therapeutic effects at short-term and predicts the benefits of epidural motor cortex stimulation (MCS). The present article summarizes the findings on application, mechanisms and therapeutic effects of cortical stimulation in neuropathic pain.

Neural mechanisms of memory retrieval: role of the prefrontal cortex.

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Hasegawa, I

2000-01-01

In the primate brain, long-term memory is stored in the neocortical association area which is also engaged in sensory perception. The coded representation of memory is retrieved via interactions of hierarchically different cortical areas along bottom-up and top-down anatomical connections. The functional significance of the fronto-cortical top-down neuronal projections has been relevantly assessed in a new experimental paradigm using posterior-split-brain monkeys. When the splenium of the corpus callosum and the anterior commissure were selectively split, the bottom-up visual signal originating from the unilateral striate cortex could not reach the contralateral visual cortical areas. In this preparation, long-term memory acquired through visual stimulus-stimulus association learning was prevented from transferring across hemispheres. Nonetheless, following the presentation of a visual cue to one hemisphere, the prefrontal cortex could instruct the contralateral hemisphere to retrieve the correct stimulus specified by the cue. These results support the hypothesis that the prefrontal cortex can regulate memory recall in the absence of bottom-up sensory input. In humans, functional neuroimaging studies have revealed activation of a distributed neural network, including the prefrontal cortex, during memory retrieval tasks. Thus, the prefrontal cortex is consistently involved in retrieval of long-term memory in primates.

Frontal eye fields control attentional modulation of alpha and gamma oscillations in contralateral occipitoparietal cortex

NARCIS (Netherlands)

Marshall, T.R.; O'Shea, J.; Jensen, O.; Bergmann, T.O.

2015-01-01

Covertly directing visuospatial attention produces a frequency-specific modulation of neuronal oscillations in occipital and parietal cortices: anticipatory alpha (8-12 Hz) power decreases contralateral and increases ipsilateral to attention, whereas stimulus-induced gamma (>40 Hz) power is boosted

The primary visual cortex in the neural circuit for visual orienting

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Zhaoping, Li

The primary visual cortex (V1) is traditionally viewed as remote from influencing brain's motor outputs. However, V1 provides the most abundant cortical inputs directly to the sensory layers of superior colliculus (SC), a midbrain structure to command visual orienting such as shifting gaze and turning heads. I will show physiological, anatomical, and behavioral data suggesting that V1 transforms visual input into a saliency map to guide a class of visual orienting that is reflexive or involuntary. In particular, V1 receives a retinotopic map of visual features, such as orientation, color, and motion direction of local visual inputs; local interactions between V1 neurons perform a local-to-global computation to arrive at a saliency map that highlights conspicuous visual locations by higher V1 responses. The conspicuous location are usually, but not always, where visual input statistics changes. The population V1 outputs to SC, which is also retinotopic, enables SC to locate, by lateral inhibition between SC neurons, the most salient location as the saccadic target. Experimental tests of this hypothesis will be shown. Variations of the neural circuit for visual orienting across animal species, with more or less V1 involvement, will be discussed. Supported by the Gatsby Charitable Foundation.

Posttraining transcranial magnetic stimulation of striate cortex disrupts consolidation early in visual skill learning.

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De Weerd, Peter; Reithler, Joel; van de Ven, Vincent; Been, Marin; Jacobs, Christianne; Sack, Alexander T

2012-02-08

Practice-induced improvements in skilled performance reflect "offline " consolidation processes extending beyond daily training sessions. According to visual learning theories, an early, fast learning phase driven by high-level areas is followed by a late, asymptotic learning phase driven by low-level, retinotopic areas when higher resolution is required. Thus, low-level areas would not contribute to learning and offline consolidation until late learning. Recent studies have challenged this notion, demonstrating modified responses to trained stimuli in primary visual cortex (V1) and offline activity after very limited training. However, the behavioral relevance of modified V1 activity for offline consolidation of visual skill memory in V1 after early training sessions remains unclear. Here, we used neuronavigated transcranial magnetic stimulation (TMS) directed to a trained retinotopic V1 location to test for behaviorally relevant consolidation in human low-level visual cortex. Applying TMS to the trained V1 location within 45 min of the first or second training session strongly interfered with learning, as measured by impaired performance the next day. The interference was conditional on task context and occurred only when training in the location targeted by TMS was followed by training in a second location before TMS. In this condition, high-level areas may become coupled to the second location and uncoupled from the previously trained low-level representation, thereby rendering consolidation vulnerable to interference. Our data show that, during the earliest phases of skill learning in the lowest-level visual areas, a behaviorally relevant form of consolidation exists of which the robustness is controlled by high-level, contextual factors.

The role of parietal cortex in the formation of colour and motion based concepts

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Samuel William Cheadle

2014-07-01

Full Text Available Imaging evidence shows that separate subdivisions of parietal cortex, in and around the intraparietal sulcus (IPS, are engaged when stimuli are grouped according to colour and to motion (Zeki and Stutters 2013. Since grouping is an essential step in the formation of concepts, we wanted to learn whether parietal cortex is also engaged in the formation of concepts according to these two attributes. Using functional magnetic resonance imaging (fMRI, and choosing the recognition of concept-based colour or motion stimuli as our paradigm, we found that there was strong concept-related activity in and around the intraparietal sulcus (IPS, a region whose homologue in the macaque monkey is known to receive direct but segregated anatomical inputs from V4 and V5. Parietal activity related to colour concepts was juxtaposed but did not overlap with activity related to motion concepts, thus emphasizing the continuation of the segregation of colour and motion into the conceptual system. Concurrent retinotopic mapping experiments showed that within the parietal cortex, concept-related activity increases within later stage IPS areas.

Neural Anatomy of Primary Visual Cortex Limits Visual Working Memory.

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Bergmann, Johanna; Genç, Erhan; Kohler, Axel; Singer, Wolf; Pearson, Joel

2016-01-01

Despite the immense processing power of the human brain, working memory storage is severely limited, and the neuroanatomical basis of these limitations has remained elusive. Here, we show that the stable storage limits of visual working memory for over 9 s are bound by the precise gray matter volume of primary visual cortex (V1), defined by fMRI retinotopic mapping. Individuals with a bigger V1 tended to have greater visual working memory storage. This relationship was present independently for both surface size and thickness of V1 but absent in V2, V3 and for non-visual working memory measures. Additional whole-brain analyses confirmed the specificity of the relationship to V1. Our findings indicate that the size of primary visual cortex plays a critical role in limiting what we can hold in mind, acting like a gatekeeper in constraining the richness of working mental function. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Evidence for unlimited capacity processing of simple features in visual cortex.

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White, Alex L; Runeson, Erik; Palmer, John; Ernst, Zachary R; Boynton, Geoffrey M

2017-06-01

Performance in many visual tasks is impaired when observers attempt to divide spatial attention across multiple visual field locations. Correspondingly, neuronal response magnitudes in visual cortex are often reduced during divided compared with focused spatial attention. This suggests that early visual cortex is the site of capacity limits, where finite processing resources must be divided among attended stimuli. However, behavioral research demonstrates that not all visual tasks suffer such capacity limits: The costs of divided attention are minimal when the task and stimulus are simple, such as when searching for a target defined by orientation or contrast. To date, however, every neuroimaging study of divided attention has used more complex tasks and found large reductions in response magnitude. We bridged that gap by using functional magnetic resonance imaging to measure responses in the human visual cortex during simple feature detection. The first experiment used a visual search task: Observers detected a low-contrast Gabor patch within one or four potentially relevant locations. The second experiment used a dual-task design, in which observers made independent judgments of Gabor presence in patches of dynamic noise at two locations. In both experiments, blood-oxygen level-dependent (BOLD) signals in the retinotopic cortex were significantly lower for ignored than attended stimuli. However, when observers divided attention between multiple stimuli, BOLD signals were not reliably reduced and behavioral performance was unimpaired. These results suggest that processing of simple features in early visual cortex has unlimited capacity.

Contralateral thalamic hypoperfusion on brain perfusion SPECT

International Nuclear Information System (INIS)

Lee, Seok Mo; Bae, Sang Kyun; Yoo, Kyung Moo; Yum, Ha Yong

2000-01-01

Brain perfusion single photon emission computed tomography (SPECT) is useful for the localization of cerebrovascular lesion and sometimes reveals more definite lesion than radiologic imaging modality such as CT or MRI does. The purpose of this study was to evaluate the diagnostic usefulness of brain perfusion SPECT in patients with hemisensory impairment. Thirteen consecutive patients (M:F= 8:5, mean age = 48) who has hemisensory impairment were included. Brain perfusion SPECT was performed after intravenous injection of 1110 MBq of Tc-99m ECD. The images were obtained using a dual-head gamma camera with ultra-high resolution collimator. Semiquantitative analysis was performed after placing multiple ROIs on cerebral cortex, basal ganglia, thalamus and cerebellum. There were 10 patients with left hemisensory impairment and 3 patients with right-sided symptom. Only 2 patients revealed abnormal signal change in the thalamus on MRI. But brain perfusion SPECT showed decreased perfusion in the thalamus in 9 patients. Six patients among 10 patients with left hemisensory impairment revealed decreased perfusion in the contralateral thalamus on brain SPECT. The other 4 patients revealed no abnormality. Two patients among 3 patients with right hemisensory impairment also showed decreased perfusion in the contralateral thalamus on brain SPECT. One patients with right hemisensory impairment showed ipsilateral perfusion decrease. Two patients who had follow-up brain perfusion SEPCT after treatment revealed normalization of perfusion in the thalamus. Brain perfusion SPECT might be a useful tool in diagnosing patients with hemisensory impairment

Contralateral peripheral neurotization for a hemiplegic hindlimb after central neurological injury.

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Zheng, Mou-Xiong; Hua, Xu-Yun; Jiang, Su; Qiu, Yan-Qun; Shen, Yun-Dong; Xu, Wen-Dong

2018-01-01

OBJECTIVE Contralateral peripheral neurotization surgery has been successfully applied to rescue motor function of the hemiplegic upper extremity in patients with central neurological injury (CNI). It may contribute to strengthened neural pathways between the contralesional cortex and paretic limbs. However, the effect of this surgery in the lower extremities remains unknown. In the present study the authors explored the effectiveness and safety of contralateral peripheral neurotization in treating a hemiplegic lower extremity following CNI in adult rats. METHODS Controlled cortical impact (CCI) was performed on the hindlimb motor cortex of 36 adult Sprague-Dawley rats to create severe unilateral traumatic brain injury models. These CCI rats were randomly divided into 3 groups. At 1 month post-CCI, the experimental group (Group 1, 12 rats) underwent contralateral L-6 to L-6 transfer, 1 control group (Group 2, 12 rats) underwent bilateral L-6 nerve transection, and another control group (Group 3, 12 rats) underwent an L-6 laminectomy without injuring the L-6 nerves. Bilateral L-6 nerve transection rats without CCI (Group 4, 12 rats) and naïve rats (Group 5, 12 rats) were used as 2 additional control groups. Beam and ladder rung walking tests and CatWalk gait analysis were performed in each rat at baseline and at 0.5, 1, 2, 4, 6, 8, and 10 months to detect the skilled walking functions and gait parameters of both hindlimbs. Histological and electromyography studies were used at the final followup to verify establishment of the traumatic brain injury model and regeneration of the L6-L6 neural pathway. RESULTS In behavioral tests, comparable motor injury in the paretic hindlimbs was observed after CCI in Groups 1-3. Group 1 started to show significantly lower slip and error rates in the beam and ladder rung walking tests than Groups 2 and 3 at 6 months post-CCI (p walking impairment in the intact hindlimbs in Groups 1 and 2 (compared with Group 3) and in the bilateral

Outcomes of Contralateral Bullae in Primary Spontaneous Pneumothorax

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Dongsub Noh

2015-12-01

Full Text Available Background: The management of contralateral bullae incidentally found in radiological studies is controversial, largely due to the unpredictability of the natural course of incidentally found contralateral bullae. This study aimed to identify the factors associated with the contralateral occurrence of primary spontaneous pneumothorax (PSP, and to characterize the outcomes of contralateral bullae incidentally found in radiological studies. Methods: From January 2005 to December 2008, 285 patients were admitted to our institution for PSP, and the patients underwent follow- up until August 2012. The relationships between the following variables and contralateral pneumothorax occurrence were evaluated: age, sex, smoking history, body mass index, ipsilateral recurrence, ipsilateral bullae size, the number of ipsilateral bullae, contralateral bullae size, and the number of contralateral bullae. Results: The study group consisted of 233 males and 29 females. The mean age and mean body index of the patients were 23.85± 9.50 years and 19.63±2.50 kg/m2. Contralateral PSP occurred in 26 patients. The five-year contralateral PSP occurrence- free survival rate was 64.3% in patients in whom contralateral bullae were found. Conclusion: The occurrence of contralateral PSP was associated with younger age, ipsilateral recurrence, and the presence of contralateral bullae. Contralateral PSP occurrence was more common in young patients and patients with recurrent PSP. Single-stage bilateral surgery should be considered if an operation is needed in young patients, patients with recurrent pneumothorax, and patients with contralateral bullae.

Attentional load modulates responses of human primary visual cortex to invisible stimuli.

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Bahrami, Bahador; Lavie, Nilli; Rees, Geraint

2007-03-20

Visual neuroscience has long sought to determine the extent to which stimulus-evoked activity in visual cortex depends on attention and awareness. Some influential theories of consciousness maintain that the allocation of attention is restricted to conscious representations [1, 2]. However, in the load theory of attention [3], competition between task-relevant and task-irrelevant stimuli for limited-capacity attention does not depend on conscious perception of the irrelevant stimuli. The critical test is whether the level of attentional load in a relevant task would determine unconscious neural processing of invisible stimuli. Human participants were scanned with high-field fMRI while they performed a foveal task of low or high attentional load. Irrelevant, invisible monocular stimuli were simultaneously presented peripherally and were continuously suppressed by a flashing mask in the other eye [4]. Attentional load in the foveal task strongly modulated retinotopic activity evoked in primary visual cortex (V1) by the invisible stimuli. Contrary to traditional views [1, 2, 5, 6], we found that availability of attentional capacity determines neural representations related to unconscious processing of continuously suppressed stimuli in human primary visual cortex. Spillover of attention to cortical representations of invisible stimuli (under low load) cannot be a sufficient condition for their awareness.

[Brodmann Areas 17, 18, and 19 in the Human Brain: An Overview].

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Kawachi, Juro

2017-04-01

Brodmann areas 17, 18, and 19 in the human brain are visual cortices of the occipital lobe. Each area has its own retinotopic representations, particulary area 19, which has many small retinotopic areas representing half or all of the contralateral visual field, several functional areas, and nine cytoarchitectonic areas. Several fasciculi are known as occipital fiber connections, but their precise endpoints are not clear. Lesions in the visual cortices cause several visual disorders including visual field defect, visual hallucinations, metamorphopsia, and different kinds of visual agnosia.

Contralateral breast cancer risk

International Nuclear Information System (INIS)

Unnithan, Jaya; Macklis, Roger M.

2001-01-01

The use of breast-conserving treatment approaches for breast cancer has now become a standard option for early stage disease. Numerous randomized studies have shown medical equivalence when mastectomy is compared to lumpectomy followed by radiotherapy for the local management of this common problem. With an increased emphasis on patient involvement in the therapeutic decision making process, it is important to identify and quantify any unforeseen risks of the conservation approach. One concern that has been raised is the question of radiation- related contralateral breast cancer after breast radiotherapy. Although most studies do not show statistically significant evidence that patients treated with breast radiotherapy are at increased risk of developing contralateral breast cancer when compared to control groups treated with mastectomy alone, there are clear data showing the amount of scattered radiation absorbed by the contralateral breast during a routine course of breast radiotherapy is considerable (several Gy) and is therefore within the range where one might be concerned about radiogenic contralateral tumors. While radiation related risks of contralateral breast cancer appear to be small enough to be statistically insignificant for the majority of patients, there may exist a smaller subset which, for genetic or environmental reasons, is at special risk for scatter related second tumors. If such a group could be predicted, it would seem appropriate to offer either special counselling or special prevention procedures aimed at mitigating this second tumor risk. The use of genetic testing, detailed analysis of breast cancer family history, and the identification of patients who acquired their first breast cancer at a very early age may all be candidate screening procedures useful in identifying such at- risk groups. Since some risk mitigation strategies are convenient and easy to utilize, it makes sense to follow the classic 'ALARA' (as low as reasonably

Functions of delay-period activity in the prefrontal cortex and mnemonic scotomas revisited

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Shintaro eFunahashi

2015-02-01

Full Text Available Working memory is one of key concepts to understand functions of the prefrontal cortex. Delay-period activity is an important neural correlate to understand the role of working memory in prefrontal functions. The importance of delay-period activity is that this activity can encode not only visuospatial information but also a variety of information including non-spatial visual features, auditory and tactile stimuli, task rules, expected reward, and numerical quantity. This activity also participates in a variety of information processing including sensory-to-motor information transformation. These mnemonic features of delay-period activity enable to perform various important operations that the prefrontal cortex participates in, such as executive controls, and therefore, support the notion that working memory is an important function to understand prefrontal functions. On the other hand, although experiments using manual versions of the delayed-response task had revealed many important findings, an oculomotor version of this task enabled us to use multiple cue positions, exclude postural orientation during the delay period, and further prove the importance of mnemonic functions of the prefrontal cortex. In addition, monkeys with unilateral lesions exhibited specific impairment only in the performance of memory-guided saccades directed toward visual cues in the visual field contralateral to the lesioned hemisphere. This result indicates that memories for visuospatial coordinates in each hemifield are processed primarily in the contralateral prefrontal cortex. This result further strengthened the idea of mnemonic functions of the prefrontal cortex. Thus, the mnemonic functions of the prefrontal cortex and delay-period activity may not need to be reconsidered, but should be emphasized.

The roles of non-retinotopic motions in visual search

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Ryohei eNakayama

2016-06-01

Full Text Available In visual search, a moving target among stationary distracters is detected more rapidly and more efficiently than a static target among moving distracters. Here we examined how this search asymmetry depends on motion signals from three distinct coordinate system – retinal, relative, and spatiotopic (head/body-centered. Our search display consisted of a target element, distracters elements, and a fixation point tracked by observers. Each element was composed of a spatial carrier grating windowed by a Gaussian envelope, and the motions of carriers, windows, and fixation were manipulated independently and used in various combinations to decouple the respective effects of motion coordinates systems on visual search asymmetry. We found that retinal motion hardly contributes to reaction times and search slopes but that relative and spatiotopic motions contribute to them substantially. Results highlight the important roles of non-retinotopic motions for guiding observer attention in visual search.

Heterogenous migraine aura symptoms correlate with visual cortex functional magnetic resonance imaging responses

DEFF Research Database (Denmark)

Arngrim, Nanna; Hougaard, Anders; Ahmadi, Khazar

2017-01-01

Objective: Migraine aura is sparsely studied due to the highly challenging task of capturing patients during aura. Cortical spreading depression (CSD) is likely the underlying phenomenon of aura. The possible correlation between the multifaceted phenomenology of aura symptoms and the effects of CSD...... on the brain has not been ascertained. Methods: Five migraine patients were studied during various forms of aura symptoms induced by hypoxia, sham hypoxia, or physical exercise with concurrent photostimulation. The blood oxygenation level–dependent (BOLD) functional magnetic resonance imaging (fMRI) signal...... response to visual stimulation was measured in retinotopic mapping–defined visual cortex areas V1 to V4. Results: We found reduced BOLD response in patients reporting scotoma and increased response in patients who only experienced positive symptoms. Furthermore, patients with bilateral visual symptoms had...

Assessing the Effect of Early Visual Cortex Transcranial Magnetic Stimulation on Working Memory Consolidation.

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van Lamsweerde, Amanda E; Johnson, Jeffrey S

2017-07-01

Maintaining visual working memory (VWM) representations recruits a network of brain regions, including the frontal, posterior parietal, and occipital cortices; however, it is unclear to what extent the occipital cortex is engaged in VWM after sensory encoding is completed. Noninvasive brain stimulation data show that stimulation of this region can affect working memory (WM) during the early consolidation time period, but it remains unclear whether it does so by influencing the number of items that are stored or their precision. In this study, we investigated whether single-pulse transcranial magnetic stimulation (spTMS) to the occipital cortex during VWM consolidation affects the quantity or quality of VWM representations. In three experiments, we disrupted VWM consolidation with either a visual mask or spTMS to retinotopic early visual cortex. We found robust masking effects on the quantity of VWM representations up to 200 msec poststimulus offset and smaller, more variable effects on WM quality. Similarly, spTMS decreased the quantity of VWM representations, but only when it was applied immediately following stimulus offset. Like visual masks, spTMS also produced small and variable effects on WM precision. The disruptive effects of both masks and TMS were greatly reduced or entirely absent within 200 msec of stimulus offset. However, there was a reduction in swap rate across all time intervals, which may indicate a sustained role of the early visual cortex in maintaining spatial information.

Frequency-Selective Attention in Auditory Scenes Recruits Frequency Representations Throughout Human Superior Temporal Cortex.

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Riecke, Lars; Peters, Judith C; Valente, Giancarlo; Kemper, Valentin G; Formisano, Elia; Sorger, Bettina

2017-05-01

A sound of interest may be tracked amid other salient sounds by focusing attention on its characteristic features including its frequency. Functional magnetic resonance imaging findings have indicated that frequency representations in human primary auditory cortex (AC) contribute to this feat. However, attentional modulations were examined at relatively low spatial and spectral resolutions, and frequency-selective contributions outside the primary AC could not be established. To address these issues, we compared blood oxygenation level-dependent (BOLD) responses in the superior temporal cortex of human listeners while they identified single frequencies versus listened selectively for various frequencies within a multifrequency scene. Using best-frequency mapping, we observed that the detailed spatial layout of attention-induced BOLD response enhancements in primary AC follows the tonotopy of stimulus-driven frequency representations-analogous to the "spotlight" of attention enhancing visuospatial representations in retinotopic visual cortex. Moreover, using an algorithm trained to discriminate stimulus-driven frequency representations, we could successfully decode the focus of frequency-selective attention from listeners' BOLD response patterns in nonprimary AC. Our results indicate that the human brain facilitates selective listening to a frequency of interest in a scene by reinforcing the fine-grained activity pattern throughout the entire superior temporal cortex that would be evoked if that frequency was present alone. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Contralateral Supracerebellar-Infratentorial Approach for Resection of Thalamic Cavernous Malformations.

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Mascitelli, Justin; Burkhardt, Jan-Karl; Gandhi, Sirin; Lawton, Michael T

2018-02-26

Surgical resection of cavernous malformations (CM) in the posterior thalamus, pineal region, and midbrain tectum is technically challenging owing to the presence of adjacent eloquent cortex and critical neurovascular structures. Various supracerebellar infratentorial (SCIT) approaches have been used in the surgical armamentarium targeting lesions in this region, including the median, paramedian, and extreme lateral variants. Surgical view of a posterior thalamic CM from the traditional ipsilateral vantage point may be obscured by occipital lobe and tentorium. To describe a novel surgical approach via a contralateral SCIT (cSCIT) trajectory for resecting posterior thalamic CMs. From 1997 to 2017, 75 patients underwent the SCIT approach for cerebrovascular/oncologic pathology by the senior author. Of these, 30 patients underwent the SCIT approach for CM resection, and 3 patients underwent the cSCIT approach. Historical patient data, radiographic features, surgical technique, and postoperative neurological outcomes were evaluated in each patient. All 3 patients presented with symptomatic CMs within the right posterior thalamus with radiographic evidence of hemorrhage. All surgeries were performed in the sitting position. There were no intraoperative complications. Neuroimaging demonstrated complete CM resection in all cases. There were no new or worsening neurological deficits or evidence of rebleeding/recurrence noted postoperatively. This study establishes the surgical feasibility of a contralateral SCIT approach in resection of symptomatic thalamic CMs It demonstrates the application for this procedure in extending the surgical trajectory superiorly and laterally and maximizing safe resectability of these deep CMs with gravity-assisted brain retraction.

Contralateral acute subdural hematoma occurring after evacuation of subdural hematoma with coexistent contralateral subdural hygroma

OpenAIRE

Sun, Hsiao-Lun; Chang, Chih-Ju; Hsieh, Cheng-Ta

2014-01-01

Burr-hole craniostomy with closed-system drainage is a safe and effective method for the management of chronic subdural hematoma. However, contralateral acute subdural hematoma has been reported to be a rare and devastating complication. Only 3 cases have been described in the literature. Herein, we reported an 80-year-old male with chronic subdural hematoma and contralateral subdural hygroma. The burr-hole craniostomy with closed-system drainage was initially performed to treat the chronic s...

Diazepam reduces excitability of amygdala and further influences auditory cortex following sodium salicylate treatment in rats.

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Song, Yu; Liu, Junxiu; Ma, Furong; Mao, Lanqun

2016-12-01

Diazepam can reduce the excitability of lateral amygdala and eventually suppress the excitability of the auditory cortex in rats following salicylate treatment, indicating the regulating effect of lateral amygdala to the auditory cortex in the tinnitus procedure. To study the spontaneous firing rates (SFR) of the auditory cortex and lateral amygdala regulated by diazepam in the tinnitus rat model induced by sodium salicylate. This study first created a tinnitus rat modal induced by sodium salicylate, and recorded SFR of both auditory cortex and lateral amygdala. Then diazepam was intraperitoneally injected and the SFR changes of lateral amygdala recorded. Finally, diazepam was microinjected on lateral amygdala and the SFR changes of the auditory cortex recorded. Both SFRs of the auditory cortex and lateral amygdala increased after salicylate treatment. SFR of lateral amygdala decreased after intraperitoneal injection of diazepam. Microinjecting diazepam to lateral amygdala decreased SFR of the auditory cortex ipsilaterally and contralaterally.

Vestibular schwannoma with contralateral facial pain – case report

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Ghodsi Mohammad

2003-03-01

Full Text Available Abstract Background Vestibular schwannoma (acoustic neuroma most commonly presents with ipsilateral disturbances of acoustic, vestibular, trigeminal and facial nerves. Presentation of vestibular schwannoma with contralateral facial pain is quite uncommon. Case presentation Among 156 cases of operated vestibular schwannoma, we found one case with unusual presentation of contralateral hemifacial pain. Conclusion The presentation of contralateral facial pain in the vestibular schwannoma is rare. It seems that displacement and distortion of the brainstem and compression of the contralateral trigeminal nerve in Meckel's cave by the large mass lesion may lead to this atypical presentation. The best practice in these patients is removal of the tumour, although persistent contralateral pain after operation has been reported.

Topographic Organization of Cholinergic Innervation From the Basal Forebrain to the Visual Cortex in the Rat

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Frédéric Huppé-Gourgues

2018-03-01

Full Text Available Acetylcholine is an important neurotransmitter for the regulation of visual attention, plasticity, and perceptual learning. It is released in the visual cortex predominantly by cholinergic projections from the basal forebrain, where stimulation may produce potentiation of visual processes. However, little is known about the fine organization of these corticopetal projections, such as whether basal forebrain neurons projecting to the primary and secondary visual cortical areas (V1 and V2, respectively are organized retinotopically. The aim of this study was to map these basal forebrain-V1/V2 projections. Microinjections of the fluorescent retrograde tracer cholera toxin b fragment in different sites within V1 and V2 in Long–Evans rats were performed. Retrogradely labeled cell bodies in the horizontal and vertical limbs of the diagonal band of Broca (HDB and VDB, respectively, nucleus basalis magnocellularis, and substantia innominata (SI, were mapped ex vivo with a computer-assisted microscope stage controlled by stereological software. Choline acetyltranferase immunohistochemistry was used to identify cholinergic cells. Our results showed a predominance of cholinergic projections coming from the HDB. These projections were not retinotopically organized but projections to V1 arised from neurons located in the anterior HDB/SI whereas projections to V2 arised from neurons located throughout the whole extent of HDB/SI. The absence of a clear topography of these projections suggests that BF activation can stimulate visual cortices broadly.

Different mechanisms of contralateral- or ipsilateral-acupuncture to modulate the brain activity in patients with unilateral chronic shoulder pain: a pilot fMRI study

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Zhang S

2018-03-01

to evaluate clinical efficiency of treatment. ReHo was used to assess resting-state brain activity.Results: We found clinical improvement in decreasing pain intensity and increasing shoulder function in both groups, and the mean objective shoulder functional improvement in contra-group was better than that in ipsi-group (p = 0.010. Interestingly, the brain mechanism of contra-acupuncture at ST 38 was distinguishable from ipsi-acupuncture regarding ReHo values.Conclusion: Anterior cingulate cortex (ACC may play a direct role in the regulation of brain by the contralateral acupuncture at ST 38 in patients with shoulder pain. On the contrary, the pathway of brainstem-thalamus-cortex may be likely to work in mechanism of acupuncture at ipsilateral ST 38.Significance: Our results indicate that the clinical effects and brain mechanisms are different between the stimulation given at contralateral and ipsilateral acupoints in patients with CSP and imply that the selection of either contralateral or ipsilateral acupuncture therapy to treat some chronic pain conditions is necessary. Keywords: region homogeneity, anterior cingulate cortex, brainstem, resting-state fMRI, ST 38

Repetitive and retinotopically restricted activation of the dorsal lateral geniculate nucleus with optogenetics.

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Alexandre Castonguay

Full Text Available Optogenetics allows the control of cellular activity using focused delivery of light pulses. In neuroscience, optogenetic protocols have been shown to efficiently inhibit or stimulate neuronal activity with a high temporal resolution. Among the technical challenges associated with the use of optogenetics, one is the ability to target a spatially specific population of neurons in a given brain structure. To address this issue, we developed a side-illuminating optical fiber capable of delivering light to specific sites in a target nucleus with added flexibility through rotation and translation of the fiber and by varying the output light power. The designed optical fiber was tested in vivo in visual structures of ChR2-expressing transgenic mice. To assess the spatial extent of neuronal activity modulation, we took advantage of the hallmark of the visual system: its retinotopic organization. Indeed, the relative position of ganglion cells in the retina is transposed in the cellular topography of both the dorsal lateral geniculate nucleus (LGN in the thalamus and the primary visual cortex (V1. The optical fiber was inserted in the LGN and by rotating it with a motor, it was possible to sequentially activate different neuronal populations within this structure. The activation of V1 neurons by LGN projections was recorded using intrinsic optical imaging. Increasing light intensity (from 1.4 to 8.9 mW/mm² led to increasing activation surfaces in V1. Optogenetic stimulation of the LGN at different translational and rotational positions was associated with different activation maps in V1. The position and/or orientation of the fiber inevitably varied across experiments, thus limiting the capacity to pool data. With the optogenetic design presented here, we demonstrate for the first time a transitory and spatially-concise activation of a deep neuronal structure. The optogenetic design presented here thus opens a promising avenue for studying the function

Inhibition of the primary motor cortex and the upgoing thumb sign

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Antonia Nucera

2017-09-01

Full Text Available Background: The upgoing thumb sign has been frequently observed in patients with minor strokes and transient ischemic attacks as an indicator of brain involvement. We assessed the effect of primary motor cortex (M1 inhibition in the development of the upgoing thumb sign. Methods: Used repetitive Transcranial Magnetic Stimulation (rTMS, 1Hz frequency for 15min, 1s ISI, 900 pulses at 60% of resting motor threshold to inhibit the right or left primary motor cortex of 10 healthy individuals. Participants were examined before and after rTMS by a neurologist who was blind to the site of motor cortex inhibition. Results: 10 neurological intact participants (5 women/5 men were recruited for this study. 2 cases were excluded due to pre-existing possible thumb signs. After the inhibition of the primary motor cortex, in 6 subjects out of 8, we observed a thumb sign contralateral to the site of primary motor cortex inhibition. In one subject an ipsilateral thumbs sign was noted. In another case, we did not find an upgoing thumb sign. Conclusion: The upgoing thumb sign is a subtle neurological finding that may be related to the primary motor cortex or corticospinal pathways involvements. Keywords: Corticospinal tract, Upper motor neuron lesions, Primary motor cortex, Transcranial magnetic stimulation

Contralateral delayed epidural hematoma following intracerebral hematoma surgery

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Solomiichuk, Volodymyr O.; Drizhdov, Konstantin I.

2013-01-01

Background: Delayed epidural hematoma (EDH) is an uncommon finding in patients after intracranial hematomas evacuation. It occurs in 6.7-7.4% of cases. A total of 29 reports were found in literature. Between them were no cases of delayed contralateral EDH after intracerebral hematoma evacuation. Case Description: This paper represents a clinical case of a 28-year-old male patient with opened penetrating head injury, who underwent left frontal lobe intracerebral hematoma evacuation and one day later a contralateral EDH was found and successfully surgically treated. Conclusion: Contralateral EDH is a life-threatening neurosurgical emergency case, which can occur during first 24 hours after decompressive craniectomy. Control CT scans must be performed next day after the operation to verify and treat contralateral EDH timely. PMID:24233058

Functional reorganization of human motor cortex after unaffected side C7 nerve root transposition

International Nuclear Information System (INIS)

Gao Gejun; Feng Xiaoyuan; Xu Wendong; Gu Yudong; Tang Weijun; Sun Guixin; Li Ke; Li Yuan; Geng Daoying

2006-01-01

Objective: To assess the characteristics of neuronal activity in human motor cortex after the seventh cervical nerve root transposition of the unaffected side by using functional MRI (fMRI). Methods: Thirteen patients who accepted the seventh cervical nerve root transposition of the unaffected side, due to total brachial plexus traction injury diagnosed by manifestation and operation, were examined retrospectively by using fMRI. 10 patients were injured on the left side and 3 on the right side. According to functional recovery of the affected hand, all subjects can be divided into 2 groups. The patients of the first group could not move the affected hand voluntarily. The patients of the second group could move the affected hand self-determined. 12 healthy volunteer's were also involved in this study as control. The fMRI examinations were performed by using echo-planer BOLD sequence. Then the SPM 99 software was used for post-processing. Results: The neuronal activation induced by the movement of both unaffected and affected upper' limb was seen in the contralateral PMC in all patients; Neuronal activation in the ipsilateral PMC evoked by movement of the unaffected extremity was seen in 10 cases, and induced by movement of the affected limb was seen in 7 cases. In the first group, the sharp of clusters in the contralateral PMC resulted by movement of the unaffected extremity showed normal in 9 eases, the average size of clusters resulted by the unaffected hand was 3159 (voxel), and resulted by the unaffected shoulder was 1746(voxel). The sharp of clusters in the contralateral PMC resulted by the affected shoulder or hand were revealed enlargement in 6 cases of each. In the second group, 1 case showed neuronal activation induced by movement of the affected limb in the PMC in both sides of motor cortex, and 2 cases showed neuronal activation in the contralateral PMC. Conclusions: Peripheral nerve injury was able to cause changes of motor cortex in human brain

Intracranial arteriovenous malformation. Contralateral steal phenomena

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Batjer, H H; Devous, M D; Seibert, G B; Purdy, P D; Ajmani, A K; Delarosa, M; Bonte, F J [Texas Univ., Dallas, TX (USA). Southwestern Medical Center

1989-05-01

Sixty-two patients with radiographically proven intracranial arteriovenous malformations underwent preoperative regional cerebral blood flow measurement with {sup 133}Xe signal-photon emission computed tomography. Contralateral regions of hypoperfusion were deteceted in all cases. Steal severity was assessed according to the contralateral steal index (ISteal(c)). ISteal(c) was < 0.7 (severe) in 22 (35%), 0.7-0.8 (intermediate) in 18 (29%), and > 0.8 (mild) in 22 (35%). ISteal(c) was more frequently severe or mild in females and more often intermediate in males in males (p < 0.05). Hyperemic complications were encountered more frequently in patients with intermediate ISteal(c) (p = 0.086). An unfavorable outcome was associated with less severe contralateral steal (p = 0.12). A detailed clinical, radiographic, and hemodynamic profile may help to preperatively identify patients at high risk for a poor surgical outcome. (author).

Functional connectivity of motor cortical network in patients with brachial plexus avulsion injury after contralateral cervical nerve transfer: a resting-state fMRI study

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Yu, Aihong; Cheng, Xiaoguang; Liang, Wei; Bai, Rongjie [The 4th Medical College of Peking University, Department of Radiology, Beijing Jishuitan Hospital, Xicheng Qu, Beijing (China); Wang, Shufeng; Xue, Yunhao; Li, Wenjun [The 4th Medical College of Peking University, Department of Hand Surgery, Beijing Jishuitan Hospital, Beijing (China)

2017-03-15

The purpose of this study is to assess the functional connectivity of the motor cortical network in patients with brachial plexus avulsion injury (BPAI) after contralateral C7 nerve transfer, using resting-state functional magnetic resonance imaging (RS-fMRI). Twelve patients with total brachial plexus root avulsion underwent RS-fMRI after contralateral C7 nerve transfer. Seventeen healthy volunteers were also included in this fMRI study as controls. The hand motor seed regions were defined as region of interests in the bilateral hemispheres. The seed-based functional connectivity was calculated in all the subjects. Differences in functional connectivity of the motor cortical network between patients and healthy controls were compared. The inter-hemispheric functional connectivity of the M1 areas was increased in patients with BPAI compared with the controls. The inter-hemispheric functional connectivity between the supplementary motor areas was reduced bilaterally. The resting-state inter-hemispheric functional connectivity of the bilateral M1 areas is altered in patients after contralateral C7 nerve transfer, suggesting a functional reorganization of cerebral cortex. (orig.)

Functional connectivity of motor cortical network in patients with brachial plexus avulsion injury after contralateral cervical nerve transfer: a resting-state fMRI study

International Nuclear Information System (INIS)

Yu, Aihong; Cheng, Xiaoguang; Liang, Wei; Bai, Rongjie; Wang, Shufeng; Xue, Yunhao; Li, Wenjun

2017-01-01

The purpose of this study is to assess the functional connectivity of the motor cortical network in patients with brachial plexus avulsion injury (BPAI) after contralateral C7 nerve transfer, using resting-state functional magnetic resonance imaging (RS-fMRI). Twelve patients with total brachial plexus root avulsion underwent RS-fMRI after contralateral C7 nerve transfer. Seventeen healthy volunteers were also included in this fMRI study as controls. The hand motor seed regions were defined as region of interests in the bilateral hemispheres. The seed-based functional connectivity was calculated in all the subjects. Differences in functional connectivity of the motor cortical network between patients and healthy controls were compared. The inter-hemispheric functional connectivity of the M1 areas was increased in patients with BPAI compared with the controls. The inter-hemispheric functional connectivity between the supplementary motor areas was reduced bilaterally. The resting-state inter-hemispheric functional connectivity of the bilateral M1 areas is altered in patients after contralateral C7 nerve transfer, suggesting a functional reorganization of cerebral cortex. (orig.)

A second-order orientation-contrast stimulus for population-receptive-field-based retinotopic mapping.

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Yildirim, Funda; Carvalho, Joana; Cornelissen, Frans W

2018-01-01

Visual field or retinotopic mapping is one of the most frequently used paradigms in fMRI. It uses activity evoked by position-varying high luminance contrast visual patterns presented throughout the visual field for determining the spatial organization of cortical visual areas. While the advantage of using high luminance contrast is that it tends to drive a wide range of neural populations - thus resulting in high signal-to-noise BOLD responses - this may also be a limitation, especially for approaches that attempt to squeeze more information out of the BOLD response, such as population receptive field (pRF) mapping. In that case, more selective stimulation of a subset of neurons - despite reduced signals - could result in better characterization of pRF properties. Here, we used a second-order stimulus based on local differences in orientation texture - to which we refer as orientation contrast - to perform retinotopic mapping. Participants in our experiment viewed arrays of Gabor patches composed of a foreground (a bar) and a background. These could only be distinguished on the basis of a difference in patch orientation. In our analyses, we compare the pRF properties obtained using this new orientation contrast-based retinotopy (OCR) to those obtained using classic luminance contrast-based retinotopy (LCR). Specifically, in higher order cortical visual areas such as LO, our novel approach resulted in non-trivial reductions in estimated population receptive field size of around 30%. A set of control experiments confirms that the most plausible cause for this reduction is that OCR mainly drives neurons sensitive to orientation contrast. We discuss how OCR - by limiting receptive field scatter and reducing BOLD displacement - may result in more accurate pRF localization as well. Estimation of neuronal properties is crucial for interpreting cortical function. Therefore, we conclude that using our approach, it is possible to selectively target particular neuronal

Changes in contralateral protein metabolism following unilateral sciatic nerve section

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Menendez, J.A.; Cubas, S.C.

1990-01-01

Changes in nerve biochemistry, anatomy, and function following injuries to the contralateral nerve have been repeatedly reported, though their significance is unknown. The most likely mechanisms for their development are either substances carried by axoplasmic flow or electrically transmitted signals. This study analyzes which mechanism underlies the development of a contralateral change in protein metabolism. The incorporation of labelled amino acids (AA) into proteins of both sciatic nerves was assessed by liquid scintillation after an unilateral section. AA were offered locally for 30 min to the distal stump of the sectioned nerves and at homologous levels of the intact contralateral nerves. At various times, from 1 to 24 h, both sciatic nerves were removed and the proteins extracted with trichloroacetic acid (TCA). An increase in incorporation was found in both nerves 14-24 h after section. No difference existed between sectioned and intact nerves, which is consistent with the contralateral effect. Lidocaine, but not colchicine, when applied previously to the nerves midway between the sectioning site and the spinal cord, inhibited the contralateral increase in AA incorporation. It is concluded that electrical signals, crossing through the spinal cord, are responsible for the development of the contralateral effect. Both the nature of the proteins and the significance of the contralateral effect are matters for speculation

Forelimb training drives transient map reorganization in ipsilateral motor cortex.

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Pruitt, David T; Schmid, Ariel N; Danaphongse, Tanya T; Flanagan, Kate E; Morrison, Robert A; Kilgard, Michael P; Rennaker, Robert L; Hays, Seth A

2016-10-15

Skilled motor training results in reorganization of contralateral motor cortex movement representations. The ipsilateral motor cortex is believed to play a role in skilled motor control, but little is known about how training influences reorganization of ipsilateral motor representations of the trained limb. To determine whether training results in reorganization of ipsilateral motor cortex maps, rats were trained to perform the isometric pull task, an automated motor task that requires skilled forelimb use. After either 3 or 6 months of training, intracortical microstimulation (ICMS) mapping was performed to document motor representations of the trained forelimb in the hemisphere ipsilateral to that limb. Motor training for 3 months resulted in a robust expansion of right forelimb representation in the right motor cortex, demonstrating that skilled motor training drives map plasticity ipsilateral to the trained limb. After 6 months of training, the right forelimb representation in the right motor cortex was significantly smaller than the representation observed in rats trained for 3 months and similar to untrained controls, consistent with a normalization of motor cortex maps. Forelimb map area was not correlated with performance on the trained task, suggesting that task performance is maintained despite normalization of cortical maps. This study provides new insights into how the ipsilateral cortex changes in response to skilled learning and may inform rehabilitative strategies to enhance cortical plasticity to support recovery after brain injury. Copyright © 2016 Elsevier B.V. All rights reserved.

Contralateral Disconnection of the Rat Prelimbic Cortex and Dorsomedial Striatum Impairs Cue-Guided Behavioral Switching

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Baker, Phillip M.; Ragozzino, Michael E.

2014-01-01

Switches in reward outcomes or reward-predictive cues are two fundamental ways in which information is used to flexibly shift response patterns. The rat prelimbic cortex and dorsomedial striatum support behavioral flexibility based on a change in outcomes. The present experiments investigated whether these two brain regions are necessary for…

Top-down modulation in human visual cortex predicts the stability of a perceptual illusion

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Meindertsma, Thomas; Hillebrand, Arjan; van Dijk, Bob W.; Lamme, Victor A. F.; Donner, Tobias H.

2014-01-01

Conscious perception sometimes fluctuates strongly, even when the sensory input is constant. For example, in motion-induced blindness (MIB), a salient visual target surrounded by a moving pattern suddenly disappears from perception, only to reappear after some variable time. Whereas such changes of perception result from fluctuations of neural activity, mounting evidence suggests that the perceptual changes, in turn, may also cause modulations of activity in several brain areas, including visual cortex. In this study, we asked whether these latter modulations might affect the subsequent dynamics of perception. We used magnetoencephalography (MEG) to measure modulations in cortical population activity during MIB. We observed a transient, retinotopically widespread modulation of beta (12–30 Hz)-frequency power over visual cortex that was closely linked to the time of subjects' behavioral report of the target disappearance. This beta modulation was a top-down signal, decoupled from both the physical stimulus properties and the motor response but contingent on the behavioral relevance of the perceptual change. Critically, the modulation amplitude predicted the duration of the subsequent target disappearance. We propose that the transformation of the perceptual change into a report triggers a top-down mechanism that stabilizes the newly selected perceptual interpretation. PMID:25411458

Complex Regional Pain Syndrome Type I Affects Brain Structure in Prefrontal and Motor Cortex

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Pleger, Burkhard; Draganski, Bogdan; Schwenkreis, Peter; Lenz, Melanie; Nicolas, Volkmar; Maier, Christoph; Tegenthoff, Martin

2014-01-01

The complex regional pain syndrome (CRPS) is a rare but debilitating pain disorder that mostly occurs after injuries to the upper limb. A number of studies indicated altered brain function in CRPS, whereas possible influences on brain structure remain poorly investigated. We acquired structural magnetic resonance imaging data from CRPS type I patients and applied voxel-by-voxel statistics to compare white and gray matter brain segments of CRPS patients with matched controls. Patients and controls were statistically compared in two different ways: First, we applied a 2-sample ttest to compare whole brain white and gray matter structure between patients and controls. Second, we aimed to assess structural alterations specifically of the primary somatosensory (S1) and motor cortex (M1) contralateral to the CRPS affected side. To this end, MRI scans of patients with left-sided CRPS (and matched controls) were horizontally flipped before preprocessing and region-of-interest-based group comparison. The unpaired ttest of the “non-flipped” data revealed that CRPS patients presented increased gray matter density in the dorsomedial prefrontal cortex. The same test applied to the “flipped” data showed further increases in gray matter density, not in the S1, but in the M1 contralateral to the CRPS-affected limb which were inversely related to decreased white matter density of the internal capsule within the ipsilateral brain hemisphere. The gray-white matter interaction between motor cortex and internal capsule suggests compensatory mechanisms within the central motor system possibly due to motor dysfunction. Altered gray matter structure in dorsomedial prefrontal cortex may occur in response to emotional processes such as pain-related suffering or elevated analgesic top-down control. PMID:24416397

Complex regional pain syndrome type I affects brain structure in prefrontal and motor cortex.

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Burkhard Pleger

Full Text Available The complex regional pain syndrome (CRPS is a rare but debilitating pain disorder that mostly occurs after injuries to the upper limb. A number of studies indicated altered brain function in CRPS, whereas possible influences on brain structure remain poorly investigated. We acquired structural magnetic resonance imaging data from CRPS type I patients and applied voxel-by-voxel statistics to compare white and gray matter brain segments of CRPS patients with matched controls. Patients and controls were statistically compared in two different ways: First, we applied a 2-sample ttest to compare whole brain white and gray matter structure between patients and controls. Second, we aimed to assess structural alterations specifically of the primary somatosensory (S1 and motor cortex (M1 contralateral to the CRPS affected side. To this end, MRI scans of patients with left-sided CRPS (and matched controls were horizontally flipped before preprocessing and region-of-interest-based group comparison. The unpaired ttest of the "non-flipped" data revealed that CRPS patients presented increased gray matter density in the dorsomedial prefrontal cortex. The same test applied to the "flipped" data showed further increases in gray matter density, not in the S1, but in the M1 contralateral to the CRPS-affected limb which were inversely related to decreased white matter density of the internal capsule within the ipsilateral brain hemisphere. The gray-white matter interaction between motor cortex and internal capsule suggests compensatory mechanisms within the central motor system possibly due to motor dysfunction. Altered gray matter structure in dorsomedial prefrontal cortex may occur in response to emotional processes such as pain-related suffering or elevated analgesic top-down control.

Early visual cortex reflects initiation and maintenance of task set

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Elkhetali, Abdurahman S.; Vaden, Ryan J.; Pool, Sean M.

2014-01-01

The human brain is able to process information flexibly, depending on a person's task. The mechanisms underlying this ability to initiate and maintain a task set are not well understood, but they are important for understanding the flexibility of human behavior and developing therapies for disorders involving attention. Here we investigate the differential roles of early visual cortical areas in initiating and maintaining a task set. Using functional Magnetic Resonance Imaging (fMRI), we characterized three different components of task set-related, but trial-independent activity in retinotopically mapped areas of early visual cortex, while human participants performed attention demanding visual or auditory tasks. These trial-independent effects reflected: (1) maintenance of attention over a long duration, (2) orienting to a cue, and (3) initiation of a task set. Participants performed tasks that differed in the modality of stimulus to be attended (auditory or visual) and in whether there was a simultaneous distractor (auditory only, visual only, or simultaneous auditory and visual). We found that patterns of trial-independent activity in early visual areas (V1, V2, V3, hV4) depend on attended modality, but not on stimuli. Further, different early visual areas play distinct roles in the initiation of a task set. In addition, activity associated with maintaining a task set tracks with a participant's behavior. These results show that trial-independent activity in early visual cortex reflects initiation and maintenance of a person's task set. PMID:25485712

The physiological basis of the effects of intermittent theta burst stimulation of the human motor cortex.

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Di Lazzaro, V; Pilato, F; Dileone, M; Profice, P; Oliviero, A; Mazzone, P; Insola, A; Ranieri, F; Meglio, M; Tonali, P A; Rothwell, J C

2008-08-15

Theta burst stimulation (TBS) is a form of repetitive transcranial magnetic stimulation (TMS). When applied to motor cortex it leads to after-effects on corticospinal and corticocortical excitability that may reflect LTP/LTD-like synaptic effects. An inhibitory form of TBS (continuous, cTBS) suppresses MEPs, and spinal epidural recordings show this is due to suppression of the I1 volley evoked by TMS. Here we investigate whether the excitatory form of TBS (intermittent, iTBS) affects the same I-wave circuitry. We recorded corticospinal volleys evoked by single pulse TMS of the motor cortex before and after iTBS in three conscious patients who had an electrode implanted in the cervical epidural space for the control of pain. As in healthy subjects, iTBS increased MEPs, and this was accompanied by a significant increase in the amplitude of later I-waves, but not the I1 wave. In two of the patients we tested the excitability of the contralateral cortex and found a significant suppression of the late I-waves. The extent of the changes varied between the three patients, as did their age. To investigate whether age might be a significant contributor to the variability we examined the effect of iTBS on MEPs in 18 healthy subjects. iTBS facilitated MEPs evoked by TMS of the conditioned hemisphere and suppressed MEPs evoked by stimulation of the contralateral hemisphere. There was a slight but non-significant decline in MEP facilitation with age, suggesting that interindividual variability was more important than age in explaining our data. In a subgroup of 10 subjects we found that iTBS had no effect on the duration of the ipsilateral silent period suggesting that the reduction in contralateral MEPs was not due to an increase in ongoing transcallosal inhibition. In conclusion, iTBS affects the excitability of excitatory synaptic inputs to pyramidal tract neurones that are recruited by a TMS pulse, both in the stimulated hemisphere and in the contralateral hemisphere

Contralateral tactile masking between forearms.

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D'Amour, Sarah; Harris, Laurence R

2014-03-01

Masking effects have been demonstrated in which tactile sensitivity is affected when one touch is close to another on the body surface. Such effects are likely a result of local lateral inhibitory circuits that sharpen the spatial tuning of a given tactile receptor. Mutually inhibitory pathways have also been demonstrated between cortical tactile maps of the two halves of the body. Occasional reports have indicated that touches on one hand or forearm can affect tactile sensitivity at contralateral locations. Here, we measure the spatial tuning and effect of posture on this contralateral masking effect. Tactile sensitivity was measured on one forearm, while vibrotactile masking stimulation was applied to the opposite arm. Results were compared to sensitivity while vibrotactile stimulation was applied to a control site on the right shoulder. Sensitivity on the forearm was reduced by over 3 dB when the arms were touching and by 0.52 dB when they were held parallel. The masking effect depended on the position of the masking stimulus. Its effectiveness fell off by 1 STD when the stimulus was 29 % of arm length from the corresponding contralateral point. This long-range inhibitory effect in the tactile system suggests a surprisingly intimate relationship between the two sides of the body.

Monaural and binaural contributions to interaural-level-difference sensitivity in human auditory cortex.

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Stecker, G Christopher; McLaughlin, Susan A; Higgins, Nathan C

2015-10-15

Whole-brain functional magnetic resonance imaging was used to measure blood-oxygenation-level-dependent (BOLD) responses in human auditory cortex (AC) to sounds with intensity varying independently in the left and right ears. Echoplanar images were acquired at 3 Tesla with sparse image acquisition once per 12-second block of sound stimulation. Combinations of binaural intensity and stimulus presentation rate were varied between blocks, and selected to allow measurement of response-intensity functions in three configurations: monaural 55-85 dB SPL, binaural 55-85 dB SPL with intensity equal in both ears, and binaural with average binaural level of 70 dB SPL and interaural level differences (ILD) ranging ±30 dB (i.e., favoring the left or right ear). Comparison of response functions equated for contralateral intensity revealed that BOLD-response magnitudes (1) generally increased with contralateral intensity, consistent with positive drive of the BOLD response by the contralateral ear, (2) were larger for contralateral monaural stimulation than for binaural stimulation, consistent with negative effects (e.g., inhibition) of ipsilateral input, which were strongest in the left hemisphere, and (3) also increased with ipsilateral intensity when contralateral input was weak, consistent with additional, positive, effects of ipsilateral stimulation. Hemispheric asymmetries in the spatial extent and overall magnitude of BOLD responses were generally consistent with previous studies demonstrating greater bilaterality of responses in the right hemisphere and stricter contralaterality in the left hemisphere. Finally, comparison of responses to fast (40/s) and slow (5/s) stimulus presentation rates revealed significant rate-dependent adaptation of the BOLD response that varied across ILD values. Copyright © 2015. Published by Elsevier Inc.

Contralateral breast cancer | Garba | Nigerian Journal of Surgical ...

African Journals Online (AJOL)

The incidence of contralateral breast cancer is increasing at a frightening rate. It ranges from 0.22% to 68%.This second breast cancer remains, however largely sub-clinical. There are pathological and clinical factors, which can be utilized to identify those women at a particularly higher risk of contralateral breast cancer.

The impact of early visual cortex transcranial magnetic stimulation on visual working memory precision and guess rate.

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Rosanne L Rademaker

Full Text Available Neuroimaging studies have demonstrated that activity patterns in early visual areas predict stimulus properties actively maintained in visual working memory. Yet, the mechanisms by which such information is represented remain largely unknown. In this study, observers remembered the orientations of 4 briefly presented gratings, one in each quadrant of the visual field. A 10Hz Transcranial Magnetic Stimulation (TMS triplet was applied directly at stimulus offset, or midway through a 2-second delay, targeting early visual cortex corresponding retinotopically to a sample item in the lower hemifield. Memory for one of the four gratings was probed at random, and participants reported this orientation via method of adjustment. Recall errors were smaller when the visual field location targeted by TMS overlapped with that of the cued memory item, compared to errors for stimuli probed diagonally to TMS. This implied topographic storage of orientation information, and a memory-enhancing effect at the targeted location. Furthermore, early pulses impaired performance at all four locations, compared to late pulses. Next, response errors were fit empirically using a mixture model to characterize memory precision and guess rates. Memory was more precise for items proximal to the pulse location, irrespective of pulse timing. Guesses were more probable with early TMS pulses, regardless of stimulus location. Thus, while TMS administered at the offset of the stimulus array might disrupt early-phase consolidation in a non-topographic manner, TMS also boosts the precise representation of an item at its targeted retinotopic location, possibly by increasing attentional resources or by injecting a beneficial amount of noise.

The impact of early visual cortex transcranial magnetic stimulation on visual working memory precision and guess rate.

Science.gov (United States)

Rademaker, Rosanne L; van de Ven, Vincent G; Tong, Frank; Sack, Alexander T

2017-01-01

Neuroimaging studies have demonstrated that activity patterns in early visual areas predict stimulus properties actively maintained in visual working memory. Yet, the mechanisms by which such information is represented remain largely unknown. In this study, observers remembered the orientations of 4 briefly presented gratings, one in each quadrant of the visual field. A 10Hz Transcranial Magnetic Stimulation (TMS) triplet was applied directly at stimulus offset, or midway through a 2-second delay, targeting early visual cortex corresponding retinotopically to a sample item in the lower hemifield. Memory for one of the four gratings was probed at random, and participants reported this orientation via method of adjustment. Recall errors were smaller when the visual field location targeted by TMS overlapped with that of the cued memory item, compared to errors for stimuli probed diagonally to TMS. This implied topographic storage of orientation information, and a memory-enhancing effect at the targeted location. Furthermore, early pulses impaired performance at all four locations, compared to late pulses. Next, response errors were fit empirically using a mixture model to characterize memory precision and guess rates. Memory was more precise for items proximal to the pulse location, irrespective of pulse timing. Guesses were more probable with early TMS pulses, regardless of stimulus location. Thus, while TMS administered at the offset of the stimulus array might disrupt early-phase consolidation in a non-topographic manner, TMS also boosts the precise representation of an item at its targeted retinotopic location, possibly by increasing attentional resources or by injecting a beneficial amount of noise.

Does area V3A predict positions of moving objects?

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Gerrit W Maus

2010-11-01

Full Text Available A gradually fading moving object is perceived to disappear at positions beyond its luminance detection threshold, whereas abrupt offsets are usually localised accurately. What role does retinotopic activity in visual cortex play in this motion-induced mislocalization of the endpoint of fading objects? Using functional magnetic resonance imaging (fMRI, we localised regions of interest (ROIs in retinotopic maps abutting the trajectory endpoint of a bar moving either towards or away from this position while gradually decreasing or increasing in luminance. Area V3A showed predictive activity, with stronger fMRI responses for motion towards versus away from the ROI. This effect was independent of the change in luminance. In Area V1 we found higher activity for high-contrast onsets and offsets near the ROI, but no significant differences between motion directions. We suggest that perceived final positions of moving objects are based on an interplay of predictive position representations in higher motion-sensitive retinotopic areas and offset transients in primary visual cortex.

Sonographic diagnosis of the contralateral ovary in patients with ovarian tumor

International Nuclear Information System (INIS)

Lee, Eun Ju; Jung, Jin Young; Lee, Chang Ho; Suh; Jung Ho

1999-01-01

To assess the usefulness of transvaginal sonography(TVS) in the detection of normal contralateral ovary and disease involvement of contralateral ovary in the patients with ovarian tumor. We compared sonographic findings with histopathologic findings of the contralateral ovary retrospectively in 87 patients, who underwent preoperative ultrasonography and laparotomy for ovarian tumor for recent 4 years. Abnormality of the contralateral ovary was confirmed in 49 (56.3%) of 87 patients. The pathologic diagnoses of contralateral ovarian lesions were bilateral involvement of the same disease in 39 patients, different tumor in four patients and non-tumorous lesion in six patients. Abnormal TVS findings of the contralateral ovary were detected in 34 of 49 patients, which shows diagnostic accuracy of 82.8%. The sensitivity and specificity were 69.4% and 100%, respectively. 15 cases which were not diagnosed by ultrasound were bilateral involvement of the same disease in 10 cases (1 serous cystadenoma, 2 cystadenocarcinoma with low malignant potential, 1 brenner tumor, 1 metastatic endometrioid cancer, 1 metastasis, 4 teratoma) and different lesions in the remaining 5 patients (2 endosalpingiosis, 1 surface inclusion cyst, 2 tuboovarian cyst). Ultrasound of the contralateral ovary in the patients with ovarian tumor shows low to a moderate degree sensitivity and accuracy. So, more intensive and targeted evaluation of contralateral ovary is needed for the more accurate diagnosis and proper treatment.

Imagery of a moving object: the role of occipital cortex and human MT/V5+.

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Kaas, Amanda; Weigelt, Sarah; Roebroeck, Alard; Kohler, Axel; Muckli, Lars

2010-01-01

Visual imagery--similar to visual perception--activates feature-specific and category-specific visual areas. This is frequently observed in experiments where the instruction is to imagine stimuli that have been shown immediately before the imagery task. Hence, feature-specific activation could be related to the short-term memory retrieval of previously presented sensory information. Here, we investigated mental imagery of stimuli that subjects had not seen before, eliminating the effects of short-term memory. We recorded brain activation using fMRI while subjects performed a behaviourally controlled guided imagery task in predefined retinotopic coordinates to optimize sensitivity in early visual areas. Whole brain analyses revealed activation in a parieto-frontal network and lateral-occipital cortex. Region of interest (ROI) based analyses showed activation in left hMT/V5+. Granger causality mapping taking left hMT/V5+ as source revealed an imagery-specific directed influence from the left inferior parietal lobule (IPL). Interestingly, we observed a negative BOLD response in V1-3 during imagery, modulated by the retinotopic location of the imagined motion trace. Our results indicate that rule-based motion imagery can activate higher-order visual areas involved in motion perception, with a role for top-down directed influences originating in IPL. Lower-order visual areas (V1, V2 and V3) were down-regulated during this type of imagery, possibly reflecting inhibition to avoid visual input from interfering with the imagery construction. This suggests that the activation in early visual areas observed in previous studies might be related to short- or long-term memory retrieval of specific sensory experiences.

Right vs. left sensorimotor cortex suction-ablation in the rat: no difference in beam-walking recovery.

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Goldstein, L B

1995-03-13

The ability of rats to traverse a narrow elevated beam has been used to quantitate recovery of hindlimb motor function after unilateral injury to the sensorimotor cortex. We tested the hypothesis that the rate of spontaneous beam-walking recovery varies with the side of the cortex lesion. Groups of rats that were trained at the beam-walking task underwent suction-ablation of either the right or left hindlimb sensorimotor cortex. There was no difference in hindlimb motor function between the groups on the first post-operative beam-waking trial carried out the day after cortex ablation and no difference between the groups in overall recovery rates over the next two weeks. Subsequent analyses of lesion surface parameters showed no differences in lesion size or extent. Regardless of the side of the lesion, there were also no differences between the right and left hemispheres in norepinephrine content of the lesioned or contralateral cortex. We conclude that the side of sensorimotor cortex ablation injury does not differentially affect the rate of spontaneous motor recovery as measured with the beam-walking task.

Asymmetric Functional Connectivity of the Contra- and Ipsilateral Secondary Somatosensory Cortex during Tactile Object Recognition

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Yinghua Yu

2018-01-01

Full Text Available In the somatosensory system, it is well known that the bilateral secondary somatosensory cortex (SII receives projections from the unilateral primary somatosensory cortex (SI, and the SII, in turn, sends feedback projections to SI. Most neuroimaging studies have clearly shown bilateral SII activation using only unilateral stimulation for both anatomical and functional connectivity across SII subregions. However, no study has unveiled differences in the functional connectivity of the contra- and ipsilateral SII network that relates to frontoparietal areas during tactile object recognition. Therefore, we used event-related functional magnetic resonance imaging (fMRI and a delayed match-to-sample (DMS task to investigate the contributions of bilateral SII during tactile object recognition. In the fMRI experiment, 14 healthy subjects were presented with tactile angle stimuli on their right index finger and asked to encode three sample stimuli during the encoding phase and one test stimulus during the recognition phase. Then, the subjects indicated whether the angle of test stimulus was presented during the encoding phase. The results showed that contralateral (left SII activity was greater than ipsilateral (right SII activity during the encoding phase, but there was no difference during the recognition phase. A subsequent psycho-physiological interaction (PPI analysis revealed distinct connectivity from the contra- and ipsilateral SII to other regions. The left SII functionally connected to the left SI and right primary and premotor cortex, while the right SII functionally connected to the left posterior parietal cortex (PPC. Our findings suggest that in situations involving unilateral tactile object recognition, contra- and ipsilateral SII will induce an asymmetrical functional connectivity to other brain areas, which may occur by the hand contralateral effect of SII.

Neuroplasticity Changes on Human Motor Cortex Induced by Acupuncture Therapy: A Preliminary Study

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Yi Yang

2017-01-01

Full Text Available While neuroplasticity changes measured by transcranial magnetic stimulation have been proved to be highly correlated to motor recovery and have been tested in various forms of interventions, it has not been applied to investigate the neurophysiologic mechanism of acupuncture therapy. The aim of this study is to investigate neuroplasticity changes induced by a single session of acupuncture therapy in healthy adults, regarding the excitability change on bilateral primary motor cortex and interhemispheric inhibition. Ten subjects took a 30-minute acupuncture therapy and the same length relaxing phase in separate days. Transcranial magnetic stimulation measures, including resting motor threshold, amplitudes of motor-evoked potential, and interhemispheric inhibition, were assessed before and 10 minutes after intervention. Acupuncture treatment showed significant changes on potential amplitude from both ipsilateral and contralateral hemispheres to acupuncture compared to baseline. Also, interhemispheric inhibition from the contralateral motor cortex to the opposite showed a significant decline. The results indicated that corticomotoneuronal excitability and interhemispheric competition could be modulated by acupuncture therapy on healthy subjects. The following question about whether these changes will be observed in the same way on stroke patients and whether they correlate with the therapeutic effect on movement need to be answered by following studies. This trial is registered with ISRCTN13074245.

Functional MR imaging of the motor cortex in healthy volunteers and patients with brain tumours: qualitative and quantitative results

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Fellner, C.; Friedrich-Alexander-Univ., Erlangen-Nuernberg; Schlaier, J.; Schwerdtner, J.; Brawanski, A.; Fellner, F.; Oberoesterreichische Landesnervenklinik, Linz; Held, P.; Blank, M.; Kalender, W.A.

1999-01-01

The purpose of this study was to compare functional magnetic resonance (MR) imaging of the motor cortex in healthy volunteers and patients with brain tumours. Functional MR imaging was performed in 14 healthy volunteers and 14 patients with tumours in or near the primary motor cortex with groups being matched for age, sex, and handedness. Functional images were acquired during motion of the right and left hand. Time courses of signal intensity within the contralateral, ipsilateral, and supplementary motor cortex as well as z-maps were calculated, their quality being assessed visually. Mean signal increase between activation and rest were evaluated within the contralateral, ipsilateral, and supplementary motor cortex, the activated area in those regions of interest was measured using z-maps. The quality of functional MR experiments was generally lower in patients than in volunteers. The quantitative results showed a trend towards increased ipsilateral activation in volunteers during left hand compared to right hand motion and in patients during motion of the affected compared to the non-affected hand. Considering quantitative and qualitative results, significantly increased ipsilateral activation was found in patients compared to healthy volunteers. In conclusion, functional MR imaging quality was significantly reduced in patient studies compared to healthy volunteers, even if influences of age, sex, and handedness were excluded. Increased ipsilateral activation was found in patients with brain tumours which can be interpreted by an improved connectivity between both hemispheres. (orig.) [de

Contralateral reinnervation of midline muscles in nonidiopathic facial palsy.

NARCIS (Netherlands)

Gilhuis, H.J.; Beurskens, C.H.G.; Vries, J. de; Marres, H.A.M.; Hartman, E.H.M.; Zwarts, M.J.

2003-01-01

The purpose of this study was to analyze contralateral reinnervation of the facial nerve in eight patients with complete facial palsy after surgery or trauma and seven healthy volunteers. All patients had contralateral reinnervation of facial muscles as demonstrated by electrical nerve stimulation

Radiographic risk factors for contralateral rupture in dogs with unilateral cranial cruciate ligament rupture.

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Connie Chuang

Full Text Available BACKGROUND: Complete cranial cruciate ligament rupture (CR is a common cause of pelvic limb lameness in dogs. Dogs with unilateral CR often develop contralateral CR over time. Although radiographic signs of contralateral stifle joint osteoarthritis (OA influence risk of subsequent contralateral CR, this risk has not been studied in detail. METHODOLOGY/PRINCIPAL FINDINGS: We conducted a retrospective longitudinal cohort study of client-owned dogs with unilateral CR to determine how severity of radiographic stifle synovial effusion and osteophytosis influence risk of contralateral CR over time. Detailed survival analysis was performed for a cohort of 85 dogs after case filtering of an initial sample population of 513 dogs. This population was stratified based on radiographic severity of synovial effusion (graded on a scale of 0, 1, and 2 and severity of osteophytosis (graded on a scale of 0, 1, 2, and 3 of both index and contralateral stifle joints using a reproducible scoring method. Severity of osteophytosis in the index and contralateral stifles was significantly correlated. Rupture of the contralateral cranial cruciate ligament was significantly influenced by radiographic OA in both the index and contralateral stifles at diagnosis. Odds ratio for development of contralateral CR in dogs with severe contralateral radiographic stifle effusion was 13.4 at one year after diagnosis and 11.4 at two years. Odds ratio for development of contralateral CR in dogs with severe contralateral osteophytosis was 9.9 at one year after diagnosis. These odds ratios were associated with decreased time to contralateral CR. Breed, age, body weight, gender, and tibial plateau angle did not significantly influence time to contralateral CR. CONCLUSION: Subsequent contralateral CR is significantly influenced by severity of radiographic stifle effusion and osteophytosis in the contralateral stifle, suggesting that synovitis and arthritic joint degeneration are

Early growth hormone (GH) treatment promotes relevant motor functional improvement after severe frontal cortex lesion in adult rats.

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Heredia, Margarita; Fuente, A; Criado, J; Yajeya, J; Devesa, J; Riolobos, A S

2013-06-15

A number of studies, in animals and humans, describe the positive effects of the growth hormone (GH) treatment combined with rehabilitation on brain reparation after brain injury. We examined the effect of GH treatment and rehabilitation in adult rats with severe frontal motor cortex ablation. Thirty-five male rats were trained in the paw-reaching-for-food task and the preferred forelimb was recorded. Under anesthesia, the motor cortex contralateral to the preferred forelimb was aspirated or sham-operated. Animals were then treated with GH (0.15 mg/kg/day, s.c) or vehicle during 5 days, commencing immediately or 6 days post-lesion. Rehabilitation was applied at short- and long-term after GH treatment. Behavioral data were analized by ANOVA following Bonferroni post hoc test. After sacrifice, immunohistochemical detection of glial fibrillary acid protein (GFAP) and nestin were undertaken in the brain of all groups. Animal group treated with GH immediately after the lesion, but not any other group, showed a significant improvement of the motor impairment induced by the motor lesion, and their performances in the motor test were no different from sham-operated controls. GFAP immunolabeling and nestin immunoreactivity were observed in the perilesional area in all injured animals; nestin immunoreactivity was higher in GH-treated injured rats (mainly in animals GH-treated 6 days post-lesion). GFAP immunoreactivity was similar among injured rats. Interestingly, nestin re-expression was detected in the contralateral undamaged motor cortex only in GH-treated injured rats, being higher in animals GH-treated immediately after the lesion than in animals GH-treated 6 days post-lesion. Early GH treatment induces significant recovery of the motor impairment produced by frontal cortical ablation. GH effects include increased neurogenesis for reparation (perilesional area) and for increased brain plasticity (contralateral motor area). Copyright © 2013 Elsevier B.V. All rights

The reactivation of somatosensory cortex and behavioral recovery after sensory loss in mature primates

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Hui-Xin eQi

2014-05-01

Full Text Available In our experiments, we removed a major source of activation of somatosensory cortex in mature monkeys by unilaterally sectioning the sensory afferents in the dorsal columns of the spinal cord at a high cervical level. At this level, the ascending branches of tactile afferents from the hand are cut, while other branches of these afferents remain intact to terminate on neurons in the dorsal horn of the spinal cord. Immediately after such a lesion, the monkeys seem relatively unimpaired in locomotion and often use the forelimb, but further inspection reveals that they prefer to use the unaffected hand in reaching for food. In addition, systematic testing indicates that they make more errors in retrieving pieces of food, and start using visual inspection of the rotated hand to confirm the success of the grasping of the food. Such difficulties are not surprising as a complete dorsal column lesion totally deactivates the contralateral hand representation in primary somatosensory cortex (area 3b. However, hand use rapidly improves over the first post-lesion weeks, and much of the hand representational territory in contralateral area 3b is reactivated by inputs from the hand in roughly a normal somatotopic pattern. Quantitative measures of single neuron response properties reveal that reactivated neurons respond to tactile stimulation on the hand with high firing rates and only slightly longer latencies. We conclude that preserved dorsal column afferents after nearly complete lesions contribute to the reactivation of cortex and the recovery of the behavior, but second-order sensory pathways in the spinal cord may also play an important role. Our microelectrode recordings indicate that these preserved first-order, and second-order pathways are initially weak and largely ineffective in activating cortex, but they are potentiated during the recovery process. Therapies that would promote this potentiation could usefully enhance recovery after spinal cord

Functional magnetic resonance imaging of the human primary visual cortex during visual stimulation

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Miki, Atsushi; Abe, Haruki; Nakajima, Takashi; Fujita, Motoi; Watanabe, Hiroyuki; Kuwabara, Takeo; Naruse, Shoji; Takagi, Mineo.

1995-01-01

Signal changes in the human primary visual cortex during visual stimulation were evaluated using non-invasive functional magnetic resonance imaging (fMRI). The experiments were performed on 10 normal human volunteers and 2 patients with homonymous hemianopsia, including one who was recovering from the exacerbation of multiple sclerosis. The visual stimuli were provided by a pattern generator using the checkerboard pattern for determining the visual evoked potential of full-field and hemifield stimulation. In normal volunteers, a signal increase was observed on the bilateral primary visual cortex during the full-field stimulation and on the contra-lateral cortex during hemifield stimulation. In the patient with homonymous hemianopsia after cerebral infarction, the signal change was clearly decreased on the affected side. In the other patient, the one recovering from multiple sclerosis with an almost normal visual field, the fMRI was within normal limits. These results suggest that it is possible to visualize the activation of the visual cortex during visual stimulation, and that there is a possibility of using this test as an objective method of visual field examination. (author)

Protein Synthesis Inhibition in the Peri-Infarct Cortex Slows Motor Recovery in Rats.

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Schubring-Giese, Maximilian; Leemburg, Susan; Luft, Andreas Rüdiger; Hosp, Jonas Aurel

2016-01-01

Neuroplasticity and reorganization of brain motor networks are thought to enable recovery of motor function after ischemic stroke. Especially in the cortex surrounding the ischemic scar (i.e., peri-infarct cortex), evidence for lasting reorganization has been found at the level of neurons and networks. This reorganization depends on expression of specific genes and subsequent protein synthesis. To test the functional relevance of the peri-infarct cortex for recovery we assessed the effect of protein synthesis inhibition within this region after experimental stroke. Long-Evans rats were trained to perform a skilled-reaching task (SRT) until they reached plateau performance. A photothrombotic stroke was induced in the forelimb representation of the primary motor cortex (M1) contralateral to the trained paw. The SRT was re-trained after stroke while the protein synthesis inhibitor anisomycin (ANI) or saline were injected into the peri-infarct cortex through implanted cannulas. ANI injections reduced protein synthesis within the peri-infarct cortex by 69% and significantly impaired recovery of reaching performance through re-training. Improvement of motor performance within a single training session remained intact, while improvement between training sessions was impaired. ANI injections did not affect infarct size. Thus, protein synthesis inhibition within the peri-infarct cortex impairs recovery of motor deficits after ischemic stroke by interfering with consolidation of motor memory between training sessions but not short-term improvements within one session.

Changes in auditory perceptions and cortex resulting from hearing recovery after extended congenital unilateral hearing loss

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Jill B Firszt

2013-12-01

Full Text Available Monaural hearing induces auditory system reorganization. Imbalanced input also degrades time-intensity cues for sound localization and signal segregation for listening in noise. While there have been studies of bilateral auditory deprivation and later hearing restoration (e.g. cochlear implants, less is known about unilateral auditory deprivation and subsequent hearing improvement. We investigated effects of long-term congenital unilateral hearing loss on localization, speech understanding, and cortical organization following hearing recovery. Hearing in the congenitally affected ear of a 41 year old female improved significantly after stapedotomy and reconstruction. Pre-operative hearing threshold levels showed unilateral, mixed, moderately-severe to profound hearing loss. The contralateral ear had hearing threshold levels within normal limits. Testing was completed prior to, and three and nine months after surgery. Measurements were of sound localization with intensity-roved stimuli and speech recognition in various noise conditions. We also evoked magnetic resonance signals with monaural stimulation to the unaffected ear. Activation magnitudes were determined in core, belt, and parabelt auditory cortex regions via an interrupted single event design. Hearing improvement following 40 years of congenital unilateral hearing loss resulted in substantially improved sound localization and speech recognition in noise. Auditory cortex also reorganized. Contralateral auditory cortex responses were increased after hearing recovery and the extent of activated cortex was bilateral, including a greater portion of the posterior superior temporal plane. Thus, prolonged predominant monaural stimulation did not prevent auditory system changes consequent to restored binaural hearing. Results support future research of unilateral auditory deprivation effects and plasticity, with consideration for length of deprivation, age at hearing correction, degree and type

Functional and structural aspects of tinnitus-related enhancement and suppression of auditory cortex activity.

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Diesch, Eugen; Andermann, Martin; Flor, Herta; Rupp, Andre

2010-05-01

The steady-state auditory evoked magnetic field was recorded in tinnitus patients and controls, both either musicians or non-musicians, all of them with high-frequency hearing loss. Stimuli were AM-tones with two modulation frequencies and three carrier frequencies matching the "audiometric edge", i.e. the frequency above which hearing loss increases more rapidly, the tinnitus frequency or the frequency 1 1/2 octaves above the audiometric edge in controls, and a frequency 1 1/2 octaves below the audiometric edge. Stimuli equated in carrier frequency, but differing in modulation frequency, were simultaneously presented to the two ears. The modulation frequency-specific components of the dual steady-state response were recovered by bandpass filtering. In both hemispheres, the source amplitude of the response was larger for contralateral than ipsilateral input. In non-musicians with tinnitus, this laterality effect was enhanced in the hemisphere contralateral and reduced in the hemisphere ipsilateral to the tinnitus ear, especially for the tinnitus frequency. The hemisphere-by-input laterality dominance effect was smaller in musicians than in non-musicians. In both patient groups, source amplitude change over time, i.e. amplitude slope, was increasing with tonal frequency for contralateral input and decreasing for ipsilateral input. However, slope was smaller for musicians than non-musicians. In patients, source amplitude was negatively correlated with the MRI-determined volume of the medial partition of Heschl's gyrus. Tinnitus patients show an altered excitatory-inhibitory balance reflecting the downregulation of inhibition and resulting in a steeper dominance hierarchy among simultaneous processes in auditory cortex. Direction and extent of this alteration are modulated by musicality and auditory cortex volume. 2010 Elsevier Inc. All rights reserved.

Effects of transcranial direct current stimulation of the motor cortex on prefrontal cortex activation during a neuromuscular fatigue task: an fNIRS study.

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Muthalib, Makii; Kan, Benjamin; Nosaka, Kazunori; Perrey, Stephane

2013-01-01

This study investigated whether manipulation of motor cortex excitability by transcranial direct current stimulation (tDCS) modulates neuromuscular fatigue and functional near-infrared spectroscopy (fNIRS)-derived prefrontal cortex (PFC) activation. Fifteen healthy men (27.7 ± 8.4 years) underwent anodal (2 mA, 10 min) and sham (2 mA, first 30 s only) tDCS delivered to the scalp over the right motor cortex. Subjects initially performed a baseline sustained submaximal (30 % maximal voluntary isometric contraction, MVC) isometric contraction task (SSIT) of the left elbow flexors until task failure, which was followed 50 min later by either an anodal or sham treatment condition, then a subsequent posttreatment SSIT. Endurance time (ET), torque integral (TI), and fNIRS-derived contralateral PFC oxygenated (O2Hb) and deoxygenated (HHb) hemoglobin concentration changes were determined at task failure. Results indicated that during the baseline and posttreatment SSIT, there were no significant differences in TI and ET, and increases in fNIRS-derived PFC activation at task failure were observed similarly regardless of the tDCS conditions. This suggests that the PFC neuronal activation to maintain muscle force production was not modulated by anodal tDCS.

Contralateral breast dose reduction using a virtual wedge

International Nuclear Information System (INIS)

Yeo, In Hwan; Kim, Dae Yong; Kim, Tae Hyun; Shin, Kyung Hwan; Chie, Eui Kyu; Park, Won; Lim, Do Hoon; Huh, Seung Jae; Ahn, Yong Chan

2005-01-01

To evaluate the contralateral breast dose using a virtual wedge compared with that using a physical wedge and an open beam in a Siemens linear accelerator. The contralateral breast dose was measured using diodes placed on a humanoid phantom. Diodes were placed at 5.5 cm (position 1), 9.5 cm (position 2), and 14 cm (position 3) along the medial-lateral line from the medial edge of the treatment field. A 6-MV photon beam was used with tangential irradiation technique at 50 and 230 degrees of gantry angle. Asymmetrically collimated 17 x 10 cm field was used. For the first set of experiment, four treatment set-ups were used, which were an open medial beam with a 30-degree wedged lateral beam (physical and virtual wedges, respectively) and a 15-degree wedge medial beam with a 15-degree wedged lateral beam (physical and virtual wedges, respectively). The second set of experiment consists of setting with medial beam without wedge, a 15-degree wedge, and a 60-degree wedge (physical and virtual wedges, respectively). Identical monitor units were delivered. Each set of experiment was repeated for three times. In the first set of experiment, the contralateral breast dose was the highest at the position 1 and decreased in order of the position 2 and 3. The contralateral breast dose was reduced with open beam on the medial side (2.70± 1.46%) compared to medial beam with a wedge (both physical and virtual) (3.25 ± 1.59%). The differences were larger with a physical wedge (0.99 ± 0.18%) than a virtual wedge (0.10 ± 0.01%) at all positions. The use of a virtual wedge reduced the contralateral breast dose by 0.12% to 1.20% of the prescribed dose compared to a physical wedge with same technique. In the second experiment, the contralateral breast dose decreased in order of the open beam, the virtual wedge, and the physical wedge at the position 1, and it decreased in order of a physical wedge, an open beam, and a virtual wedge at the position 2 and 3. The virtual wedge equipped

Structural and functional changes across the visual cortex of a patient with visual form agnosia.

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Bridge, Holly; Thomas, Owen M; Minini, Loredana; Cavina-Pratesi, Cristiana; Milner, A David; Parker, Andrew J

2013-07-31

Loss of shape recognition in visual-form agnosia occurs without equivalent losses in the use of vision to guide actions, providing support for the hypothesis of two visual systems (for "perception" and "action"). The human individual DF received a toxic exposure to carbon monoxide some years ago, which resulted in a persisting visual-form agnosia that has been extensively characterized at the behavioral level. We conducted a detailed high-resolution MRI study of DF's cortex, combining structural and functional measurements. We present the first accurate quantification of the changes in thickness across DF's occipital cortex, finding the most substantial loss in the lateral occipital cortex (LOC). There are reduced white matter connections between LOC and other areas. Functional measures show pockets of activity that survive within structurally damaged areas. The topographic mapping of visual areas showed that ordered retinotopic maps were evident for DF in the ventral portions of visual cortical areas V1, V2, V3, and hV4. Although V1 shows evidence of topographic order in its dorsal portion, such maps could not be found in the dorsal parts of V2 and V3. We conclude that it is not possible to understand fully the deficits in object perception in visual-form agnosia without the exploitation of both structural and functional measurements. Our results also highlight for DF the cortical routes through which visual information is able to pass to support her well-documented abilities to use visual information to guide actions.

Androgen receptor immunoreactivity in rat occipital cortex after callosotomy

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G Lepore

2009-08-01

Full Text Available Gonadal steroidogenesis can be influenced by direct neural links between the central nervous system and the gonads. It is known that androgen receptor (AR is expressed in many areas of the rat brain involved in neuroendocrine control of reproduction, such as the cerebral cortex. It has been recently shown that the occipital cortex exerts an inhibitory effect on testicular stereoidogenesis by a pituitary-independent neural mechanism. Moreover, the complete transection of the corpus callosum leads to an increase in testosterone (T secretion of hemigonadectomized rats. The present study was undertaken to analyze the possible corticocortical influences regulating male reproductive activities. Adult male Wistar rats were divided into 4 groups: 1 intact animals as control; 2 rats undergoing sham callosotomy; 3 posterior callosotomy; 4 gonadectomy and posterior callosotomy. Western blot analysis showed no remarkable variations in cortical AR expression in any of the groups except in group I where a significant decrease in AR levels was found. Similarly, both immunocytochemical study and cell count estimation showed a lower AR immunoreactivity in occipital cortex of callosotomized rats than in other groups. In addition, there was no difference in serum T and LH concentration between sham-callosotomized and callosotomized rats. In conclusion, our results show that posterior callosotomy led to a reduction in AR in the right occipital cortex suggesting a putative inhibiting effect of the contralateral cortical area.

Contralateral Abdominal Pocketing in Salvation of Replanted Fingertips with Compromised Circulation

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Hyung-Sup Shim

2014-01-01

Full Text Available Abdominal pocketing is one of the most useful methods in salvation of compromised replanted fingertips. Abdominal pocketing has generally been performed in the ipsilateral lower abdominal quadrant, but we have also performed contralateral pocketing at our institute. To determine which approach is more beneficial, a total of 40 patients underwent an abdominal pocketing procedure in either the ipsilateral or contralateral lower abdominal quadrant after fingertip replantation. Dates of abdominal pocketing after initial replantation, detachment after abdominal pocketing, range of motion (ROM before abdominal pocketing, and sequential ROM after the detachment operation and date of full ROM recovery and Disabilities of Arm, Shoulder, and Hand questionnaire (DASH score were recorded through medical chart review. Mean detachment date, mean abduction of shoulder after the detachment operation, and mean days to return to full ROM were not significantly different between the ipsilateral and contralateral pocketing groups. However, the mean DASH score was significantly lower in the contralateral group than the ipsilateral group. There were also fewer postoperative wound complications in the contralateral group than in the ipsilateral group. We, therefore, recommend contralateral abdominal pocketing rather than ipsilateral abdominal pocketing to increase patient comfort and reduce pain and complications.

Contralateral Abdominal Pocketing in Salvation of Replanted Fingertips with Compromised Circulation

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Shim, Hyung-Sup; Kim, Dong-Hwi; Kwon, Ho; Jung, Sung-No

2014-01-01

Abdominal pocketing is one of the most useful methods in salvation of compromised replanted fingertips. Abdominal pocketing has generally been performed in the ipsilateral lower abdominal quadrant, but we have also performed contralateral pocketing at our institute. To determine which approach is more beneficial, a total of 40 patients underwent an abdominal pocketing procedure in either the ipsilateral or contralateral lower abdominal quadrant after fingertip replantation. Dates of abdominal pocketing after initial replantation, detachment after abdominal pocketing, range of motion (ROM) before abdominal pocketing, and sequential ROM after the detachment operation and date of full ROM recovery and Disabilities of Arm, Shoulder, and Hand questionnaire (DASH) score were recorded through medical chart review. Mean detachment date, mean abduction of shoulder after the detachment operation, and mean days to return to full ROM were not significantly different between the ipsilateral and contralateral pocketing groups. However, the mean DASH score was significantly lower in the contralateral group than the ipsilateral group. There were also fewer postoperative wound complications in the contralateral group than in the ipsilateral group. We, therefore, recommend contralateral abdominal pocketing rather than ipsilateral abdominal pocketing to increase patient comfort and reduce pain and complications. PMID:25379539

Dopamine release in human striatum induced by repetitive transcranial magnetic stimulation over dorsolateral prefrontal cortex

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Cho, Sang Soo; Yoon, Eun Jin; Kim, Yu Kyeong; Lee, Won Woo; Kim, Sang Eun [Seoul National University College of Medicine, Seoul (Korea, Republic of)

2005-07-01

Animal study suggests that prefrontal cortex plays an important Animal studies suggest that prefrontal cortex plays an important role in the modulation of dopamine (DA) release in subcortical areas. However, little is known about the relationship between DA release and prefrontal activation in human. We investigated whether repetitive transcranial magnetic stimulation (rTMS) over left dorsolateral prefrontal cortex (DLPFC) influences DA release in human striatum with SPECT measurements of striatal binding of [123I)iodobenzamide (IBZM), a DA D2 receptor radioligand that is sensitive to endogenous DA. Five healthy male volunteers (age, 25{+-}2 yr) were studied with brain [123I]IBZM SPECT under three conditions (resting, Sham stimulation, and active rTMS over left DLPFC), while receiving a bolus plus constant infusion of [123I]IBZM DLPFC was defined as a 6 cm anterior and 1cm lateral from the primary motor cortex. rTMS session consisted of three blocks, in each block, 15 trains of 2 see duration were delivered with 10 Hz stimulation frequency, 100% motor threshold, and between-train intervals of 10 sec. Striatal V3', calculated as (striatal - occipital) / occipital activity ratio, was measured under equilibrium condition, at baseline and after sham and active rTMS. Sham stimulation did not affect striatal V3'. rTMS over DLPFC induced reduction of V3' in the ipsilateral and contralateral striatum by 9.7% {+-} 1.3% and 10.6% {+-} 3.2%, respectively, compared with sham procedures (P < 0.01 and P < 0.01, respectively), indicating striatal DA release elicited by rTMS over DLPFC. V3' reduction in the ipsilateral caudate nucleus was greater than that in the contralateral caudate nucleus (9.9% {+-} 4.5% vs. 6.6% {+-} 3.1%, P < 0.05). These data demonstrate DA release in human striatum induced by rTMS over DLPFC, supporting that cortico-striatal fibers originating in prefrontal cortex are involved in local DA release.

Dopamine release in human striatum induced by repetitive transcranial magnetic stimulation over dorsolateral prefrontal cortex

International Nuclear Information System (INIS)

Cho, Sang Soo; Yoon, Eun Jin; Kim, Yu Kyeong; Lee, Won Woo; Kim, Sang Eun

2005-01-01

Animal study suggests that prefrontal cortex plays an important Animal studies suggest that prefrontal cortex plays an important role in the modulation of dopamine (DA) release in subcortical areas. However, little is known about the relationship between DA release and prefrontal activation in human. We investigated whether repetitive transcranial magnetic stimulation (rTMS) over left dorsolateral prefrontal cortex (DLPFC) influences DA release in human striatum with SPECT measurements of striatal binding of [123I)iodobenzamide (IBZM), a DA D2 receptor radioligand that is sensitive to endogenous DA. Five healthy male volunteers (age, 25±2 yr) were studied with brain [123I]IBZM SPECT under three conditions (resting, Sham stimulation, and active rTMS over left DLPFC), while receiving a bolus plus constant infusion of [123I]IBZM DLPFC was defined as a 6 cm anterior and 1cm lateral from the primary motor cortex. rTMS session consisted of three blocks, in each block, 15 trains of 2 see duration were delivered with 10 Hz stimulation frequency, 100% motor threshold, and between-train intervals of 10 sec. Striatal V3', calculated as (striatal - occipital) / occipital activity ratio, was measured under equilibrium condition, at baseline and after sham and active rTMS. Sham stimulation did not affect striatal V3'. rTMS over DLPFC induced reduction of V3' in the ipsilateral and contralateral striatum by 9.7% ± 1.3% and 10.6% ± 3.2%, respectively, compared with sham procedures (P < 0.01 and P < 0.01, respectively), indicating striatal DA release elicited by rTMS over DLPFC. V3' reduction in the ipsilateral caudate nucleus was greater than that in the contralateral caudate nucleus (9.9% ± 4.5% vs. 6.6% ± 3.1%, P < 0.05). These data demonstrate DA release in human striatum induced by rTMS over DLPFC, supporting that cortico-striatal fibers originating in prefrontal cortex are involved in local DA release

Neural sources of visual working memory maintenance in human parietal and ventral extrastriate visual cortex.

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Becke, Andreas; Müller, Notger; Vellage, Anne; Schoenfeld, Mircea Ariel; Hopf, Jens-Max

2015-04-15

Maintaining information in visual working memory is reliably indexed by the contralateral delay activity (CDA) - a sustained modulation of the event-related potential (ERP) with a topographical maximum over posterior scalp regions contralateral to the memorized input. Based on scalp topography, it is hypothesized that the CDA reflects neural activity in the parietal cortex, but the precise cortical origin of underlying electric activity was never determined. Here we combine ERP recordings with magnetoencephalography based source localization to characterize the cortical current sources generating the CDA. Observers performed a cued delayed match to sample task where either the color or the relative position of colored dots had to be maintained in memory. A detailed source-localization analysis of the magnetic activity in the retention interval revealed that the magnetic analog of the CDA (mCDA) is generated by current sources in the parietal cortex. Importantly, we find that the mCDA also receives contribution from current sources in the ventral extrastriate cortex that display a time-course similar to the parietal sources. On the basis of the magnetic responses, forward modeling of ERP data reveals that the ventral sources have non-optimal projections and that these sources are therefore concealed in the ERP by overlapping fields with parietal projections. The present observations indicate that visual working memory maintenance, as indexed by the CDA, involves the parietal cortical regions as well as the ventral extrastriate regions, which code the sensory representation of the memorized content. Copyright © 2015 Elsevier Inc. All rights reserved.

Acoustic Trauma Changes the Parvalbumin-Positive Neurons in Rat Auditory Cortex

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Congli Liu

2018-01-01

Full Text Available Acoustic trauma is being reported to damage the auditory periphery and central system, and the compromised cortical inhibition is involved in auditory disorders, such as hyperacusis and tinnitus. Parvalbumin-containing neurons (PV neurons, a subset of GABAergic neurons, greatly shape and synchronize neural network activities. However, the change of PV neurons following acoustic trauma remains to be elucidated. The present study investigated how auditory cortical PV neurons change following unilateral 1 hour noise exposure (left ear, one octave band noise centered at 16 kHz, 116 dB SPL. Noise exposure elevated the auditory brainstem response threshold of the exposed ear when examined 7 days later. More detectable PV neurons were observed in both sides of the auditory cortex of noise-exposed rats when compared to control. The detectable PV neurons of the left auditory cortex (ipsilateral to the exposed ear to noise exposure outnumbered those of the right auditory cortex (contralateral to the exposed ear. Quantification of Western blotted bands revealed higher expression level of PV protein in the left cortex. These findings of more active PV neurons in noise-exposed rats suggested that a compensatory mechanism might be initiated to maintain a stable state of the brain.

Limiar e latência do reflexo acústico sob efeito de estimulação contralateral Threshold and latency of acoustic reflex under effect of contralateral noise

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Isabella Elias Burjato Raposo do Amaral

2008-03-01

Full Text Available OBJETIVO: Investigar o efeito inibitório da via eferente auditiva na variação do limiar e da latência do reflexo acústico ipsilateral com estimulação contralateral. MÉTODOS: Foram avaliados 17 pacientes entre 18 e 30 anos, com audição dentro dos padrões de normalidade submetidos à pesquisa de limiar e de latência do reflexo acústico, com e sem estimulação contralateral. RESULTADOS: Foram observadas médias de latência sem ruído contralateral para as freqüências de 500, 1000 e 2000 Hz respectivamente em 234,48, 214,96 e 236,71 milissegundos. Os valores de latência com ruído nas mesmas freqüências foram 230,74, 214,00 e 232,15 milissegundos. CONCLUSÃO: Houve diminuição da latência e aumento dos limiares do reflexo acústico quando apresentado estímulo supressor na orelha contralateral.PURPOSE: To investigate the inhibitory effect of the efferent auditory path in the variation of the threshold and the latency of ipsilateral acoustic reflex with contralateral stimulation. METHODS: Seventeen male and female patients, with ages between 18 and 30 years and with average normal hearing, were evaluated. After verification of inclusion criteria, the subjects were submitted to acoustic reflex threshold and latency testings, with and without contralateral masking. RESULTS: The latency average rates without contralateral noise at the frequencies 500 Hz, 1000 Hz and 2000 Hz were, respectively, 234,48, 214,96 and 236,71 milliseconds. The latency rates with noise at the same frequencies were 230,74, 214,00 and 232,15 milliseconds. CONCLUSION: The results showed latency decrease and increase on the acoustic reflex thresholds with contralateral white noise suppressor stimulus.

Brightness and transparency in the early visual cortex.

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Salmela, Viljami R; Vanni, Simo

2013-06-24

Several psychophysical studies have shown that transparency can have drastic effects on brightness and lightness. However, the neural processes generating these effects have remained unresolved. Several lines of evidence suggest that the early visual cortex is important for brightness perception. While single cell recordings suggest that surface brightness is represented in the primary visual cortex, the results of functional magnetic resonance imaging (fMRI) studies have been discrepant. In addition, the location of the neural representation of transparency is not yet known. We investigated whether the fMRI responses in areas V1, V2, and V3 correlate with brightness and transparency. To dissociate the blood oxygen level-dependent (BOLD) response to brightness from the response to local border contrast and mean luminance, we used variants of White's brightness illusion, both opaque and transparent, in which luminance increments and decrements cancel each other out. The stimuli consisted of a target surface and a surround. The surround luminance was always sinusoidally modulated at 0.5 Hz to induce brightness modulation to the target. The target luminance was constant or modulated in counterphase to null brightness modulation. The mean signal changes were calculated from the voxels in V1, V2, and V3 corresponding to the retinotopic location of the target surface. The BOLD responses were significantly stronger for modulating brightness than for stimuli with constant brightness. In addition, the responses were stronger for transparent than for opaque stimuli, but there was more individual variation. No interaction between brightness and transparency was found. The results show that the early visual areas V1-V3 are sensitive to surface brightness and transparency and suggest that brightness and transparency are represented separately.

Motor cortex changes after amputation are modulated by phantom limb motor control rather than pain

DEFF Research Database (Denmark)

Raffin, Estelle E.; Pascal, Giraux,; Karen, Reilly,

Amputation of a limb induces reorganization within the contralateral primary motor cortex (M1-c) (1-3). In the case of hand amputation, M1-c areas evoking movements in the face and the remaining part of the upper-limb expand toward the hand area. Despite this expansion, the amputated hand still...... reorganization and the residual M1-c activity of the amputated hand is unknown. This fMRI study aimed to determine this relationship...

Unilateral megalencephaly associated with contralateral neuronal migration defect

International Nuclear Information System (INIS)

Arslan, A.; Demirci, A; Ciftci, E.

1999-01-01

A case of unilateral megalencephaly associated with contralateral cortical dysplasia and grey matter heterotopia is reported. The corpus callosum is agenetic and the basal ganglia are dysplastic. Unilateral megalencephaly (UM) is a rare malformation characterized by unilateral enlargement of one cerebral hemisphere with ipsilateral lateral ventricle dilatation, abnormal gyral pattern and cortical thickening. Association of UM with contralateral cortical dysplasia, grey matter heterotopia and corpus callosum agenesis has not been reported in previous studies. Copyright (1999) Blackwell Science Pty Ltd

Contralateral flow reduction in unilateral stroke: evidence for transhemispheric diaschisis

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Lagreze, H.L.; Levine, R.L.; Pedula, K.L.; Nickles, R.J.; Sunderland, J.S.; Rowe, B.R.

1987-01-01

Using clinical presentation, angiography, computed tomography, and nuclear magnetic resonance imaging, 7 patients were identified who had strictly unilateral hemispheric infarction and unilateral cerebrovascular disease. In 6, cerebral blood flow measured by fluorine-18-fluoromethane inhalation and positron emission tomography was reduced in the contralateral hemisphere (p less than 0.05). Multiple regression analysis demonstrated a high correlation between contralateral flow reduction and the degree of flow impairment in the infarcted area (r = 0.941, p = 0.0014) but not with age, risk factor profile, blood pressure, PCO 2 , hematocrit, or duration of stroke. We conclude that transhemispheric diaschisis best explains the contralateral flow reduction seen in supratentorial ischemic stroke

Frequency specific modulation of human somatosensory cortex

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Matteo eFeurra

2011-02-01

Full Text Available Oscillatory neuronal activities are commonly observed in response to sensory stimulation. However, their functional roles are still the subject of debate. One way to probe the roles of oscillatory neural activities is to deliver alternating current to the cortex at biologically relevant frequencies and examine whether such stimulation influences perception and cognition. In this study, we tested whether transcranial alternating current stimulation (tACS over the primary somatosensory cortex (SI could elicit tactile sensations in humans in a frequency dependent manner. We tested the effectiveness of tACS over SI at frequency bands ranging from 2 to 70 Hz. Our results show that stimulation in alpha (10-14 Hz and high gamma (52-70 Hz frequency range produces a tactile sensation in the contralateral hand. A weaker effect was also observed for beta (16-20 Hz stimulation. These findings highlight the frequency-dependency of effective tACS over SI with the effective frequencies corresponding to those observed in previous EEG/MEG studies of tactile perception. Our present study suggests that tACS could be used as a powerful online stimulation technique to reveal the causal roles of oscillatory brain activities.

Retinotopy and attention to the face and house images in the human visual cortex.

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Wang, Bin; Yan, Tianyi; Ohno, Seiichiro; Kanazawa, Susumu; Wu, Jinglong

2016-06-01

Attentional modulation of the neural activities in human visual areas has been well demonstrated. However, the retinotopic activities that are driven by face and house images and attention to face and house images remain unknown. In the present study, we used images of faces and houses to estimate the retinotopic activities that were driven by both the images and attention to the images, driven by attention to the images, and driven by the images. Generally, our results show that both face and house images produced similar retinotopic activities in visual areas, which were only observed in the attention + stimulus and the attention conditions, but not in the stimulus condition. The fusiform face area (FFA) responded to faces that were presented on the horizontal meridian, whereas parahippocampal place area (PPA) rarely responded to house at any visual field. We further analyzed the amplitudes of the neural responses to the target wedge. In V1, V2, V3, V3A, lateral occipital area 1 (LO-1), and hV4, the neural responses to the attended target wedge were significantly greater than those to the unattended target wedge. However, in LO-2, ventral occipital areas 1 and 2 (VO-1 and VO-2) and FFA and PPA, the differences were not significant. We proposed that these areas likely have large fields of attentional modulation for face and house images and exhibit responses to both the target wedge and the background stimuli. In addition, we proposed that the absence of retinotopic activity in the stimulus condition might imply no perceived difference between the target wedge and the background stimuli.

Contralateral breast cancer: incidence according to ductal or lobular phenotype of the primary

International Nuclear Information System (INIS)

Langlands, F.; White, J.; Kearins, O.; Cheung, S.; Burns, R.; Horgan, K.; Sharma, N.; Dodwell, D.

2016-01-01

Aim: To identify differences in the incidence of contralateral breast cancer between patients with a primary tumour diagnosis of invasive ductal carcinoma (IDC) and those with a diagnosis of invasive lobular carcinoma (ILC). Materials and methods: Data from two large cancer registries (registry A & B) the Northern and Yorkshire Cancer Registry Information Service (NYCRIS) and the West Midlands Cancer Intelligence Unit (WMCIU) from 1998–2003 for all cases of invasive breast cancer of either pure ductal or pure lobular reported histology were obtained. The invasive status of the contralateral tumour diagnosis and tumour morphology was collected. Chi-square tests were undertaken to examine the differences in contralateral rates for both registries and univariate analysis to ascertain which predictors affected contralateral breast cancer risk for registry A the WMCIU cases. Results: A total of 38,132 patients were studied, 32,735 patients with IDC and 5397 (14.2%) patients with ILC over the 6-year period. There was no significant difference between the occurrence and time to occurrence of contralateral breast cancer according to original cancer histology, 901 (2.8%) patients with IDC versus 166 (3.1%) patients with ILC (p=0.169). The analysis of registry A cases showed no association between original histology (ductal versus lobular), age at diagnosis, tumour grade, use of radiotherapy for the primary cancer or use of systemic therapy (chemotherapy and/or endocrine therapy), and development of a contralateral breast cancer. Conclusion: There is no apparent increase in risk of developing a contralateral breast cancer according to the primary cancer histology either IDC or ILC. Standard mammographic follow-up does not need to take account of original tumour pathology. Increased intervention or post-treatment surveillance for the contralateral breast is not indicated in the context of ILC. The role of MRI should be restricted to those patients with ILC who are planning

The Mirror Illusion Increases Motor Cortex Excitability in Children With and Without Hemiparesis.

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Grunt, Sebastian; Newman, Christopher J; Saxer, Stefanie; Steinlin, Maja; Weisstanner, Christian; Kaelin-Lang, Alain

2017-03-01

Mirror therapy provides a visual illusion of a normal moving limb by using the mirror reflection of the unaffected arm instead of viewing the paretic limb and is used in rehabilitation to improve hand function. Little is known about the mechanism underlying its effect in children with hemiparesis. To investigate the effect of the mirror illusion (MI) on the excitability of the primary motor cortex (M1) in children and adolescents. Twelve patients with hemiparesis (10-20 years) and 8 typically developing subjects (8-17 years) participated. Corticospinal reorganization was classified as contralateral (projection from contralateral hemisphere to affected hand) or ipsilateral (projection from ipsilateral hemisphere to affected hand). M1 excitability of the hemisphere projecting to the affected (nondominant in typically developing subjects) hand was obtained during 2 different conditions using single-pulse transcranial magnetic stimulation (TMS). Each condition (without/with mirror) consisted of a unimanual and a bimanual task. Motor-evoked potentials (MEPs) were recorded from the abductor pollicis brevis and flexor digitorum superficialis muscles. MEP amplitudes were significantly increased during the mirror condition ( P = .005) in typically developing subjects and in patients with contralateral reorganization. No significant effect of MI was found in subjects with ipsilateral reorganization. MI increased M1 excitability during active movements only. This increase was not correlated to hand function. MI increases the excitability of M1 in hemiparetic patients with contralateral corticospinal organization and in typically developing subjects. This finding provides neurophysiological evidence supporting the application of mirror therapy in selected children and adolescents with hemiparesis.

Contralateral Suppression of DPOAEs in Mice after Ouabain Treatment

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Jieying Li

2018-01-01

Full Text Available Medial olivocochlear (MOC efferent feedback is suggested to protect the ear from acoustic injury and to increase its ability to discriminate sounds against a noisy background. We investigated whether type II spiral ganglion neurons participate in the contralateral suppression of the MOC reflex. The application of ouabain to the round window of the mouse cochlea selectively induced the apoptosis of the type I spiral ganglion neurons, left the peripherin-immunopositive type II spiral ganglion neurons intact, and did not affect outer hairs, as evidenced by the maintenance of the distorted product otoacoustic emissions (DPOAEs. With the ouabain treatment, the threshold of the auditory brainstem response increased significantly and the amplitude of wave I decreased significantly in the ouabain-treated ears, consistent with the loss of type I neurons. Contralateral suppression was measured as reduction in the amplitude of the 2f1−f2 DPOAEs when noise was presented to the opposite ear. Despite the loss of all the type I spiral ganglion neurons, virtually, the amplitude of the contralateral suppression was not significantly different from the control when the suppressor noise was delivered to the treated cochlea. These results are consistent with the type II spiral ganglion neurons providing the sensory input driving contralateral suppression of the MOC reflex.

Partial lumbosacral transitional vertebra resection for contralateral facetogenic pain.

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Brault, J S; Smith, J; Currier, B L

2001-01-15

Case report of surgically treated mechanical low back pain from the facet joint contralateral to a unilateral anomalous lumbosacral articulation (Bertolotti's syndrome). To describe the clinical presentation, diagnostic evaluation, and management of facet-related low back pain in a 17-year-old cheerleader and its successful surgical treatment with resection of a contralateral anomalous articulation. Lumbosacral transitional vertebrae are common in the general population. Bertolotti's syndrome is mechanical low back pain associated with these transitional segments. Little is known about the pathophysiology and mechanics of these vertebral segments and their propensity to be pain generators. Treatment of this syndrome is controversial, and surgical intervention has been infrequently reported. A retrospective chart analysis and radiographic review were performed. Repeated fluoroscopically guided injections implicated a symptomatic L6-S1 facet joint contralateral to an anomalous lumbosacral articulation. Eventually, a successful surgical outcome was achieved with resection of the anomalous articulation. Clinicians should consider the possibility that mechanical low back pain may occur from a facet contralateral to a unilateral anomalous lumbosacral articulation, even in a young patient. Although reports of surgical treatment of Bertolotti's syndrome are infrequent, resection of the anomalous articulation provided excellent results in this patient, presumably because of reduced stresses on the symptomatic facet.

Contralateral limb during total contact casting. A dynamic pressure and thermometric analysis.

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Armstrong, D G; Liswood, P J; Todd, W F

1995-12-01

The authors draw attention to the importance of evaluation of the contralateral limb when treating unilateral sequelae secondary to distal symmetrical polyneuropathy. Plantar pressure measurements of the contralateral limb during total contact casting are reviewed. The results of thermometric evaluation before and after initiation of repetitive stress were reviewed. The results suggest that the patient walking in a total contact cast may experience a reduced focal pressure on the contralateral limb when compared with uncasted walking and three-point walking with crutches. Dermal thermometry may be a highly sensitive tool in evaluating even mild increases in repetitive stress. To explain this decrease in contralateral stress, the authors examine the features inherent to the total contact cast and propose the concept of proprioceptive stability.

Real-time monitoring of ischemic and contralateral brain pO2 during stroke by variable length multisite resonators.

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Hou, Huagang; Li, Hongbin; Dong, Ruhong; Khan, Nadeem; Swartz, Harold

2014-06-01

Electron paramagnetic resonance (EPR) oximetry using variable length multi-probe implantable resonator (IR), was used to investigate the temporal changes in the ischemic and contralateral brain pO2 during stroke in rats. The EPR signal to noise ratio (S/N) of the IR with four sensor loops at a depth of up to 11 mm were compared with direct implantation of lithium phthalocyanine (LiPc, oximetry probe) deposits in vitro. These IRs were used to follow the temporal changes in pO2 at two sites in each hemisphere during ischemia induced by left middle cerebral artery occlusion (MCAO) in rats breathing 30% O2 or 100% O2. The S/N ratios of the IRs were significantly greater than the LiPc deposits. A similar pO2 at two sites in each hemisphere prior to the onset of ischemia was observed in rats breathing 30% O2. However, a significant decline in the pO2 of the left cortex and striatum occurred during ischemia, but no change in the pO2 of the contralateral brain was observed. A significant increase in the pO2 of only the contralateral non-ischemic brain was observed in the rats breathing 100% O2. No significant difference in the infarct volume was evident between the animals breathing 30% O2 or 100% O2 during ischemia. EPR oximetry with IRs can repeatedly assess temporal changes in the brain pO2 at four sites simultaneously during stroke. This oximetry approach can be used to test and develop interventions to rescue ischemic tissue by modulating cerebral pO2 during stroke. Copyright © 2014 Elsevier Inc. All rights reserved.

Shielding of the contralateral breast during tangential irradiation.

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Goffman, Thomas E; Miller, Michael; Laronga, Christine; Oliver, Shelly; Wong, Ping

2004-08-01

The purpose of this study was to investigate both optimal and practical contralateral breast shielding during tangential irradiation in young patients. A shaped sheet of variable thickness of lead was tested on a phantom with rubber breasts, and an optimized shield was created. Testing on 18 consecutive patients 50 years or younger showed shielding consistently reduced contralateral breast dose to at least half, with small additional reduction after removal of the medial wedge. For younger patients in whom radiation exposure is of considerable concern, a simple shield of 2 mm lead thickness proved practical and effective.

Risk of contralateral avascular necrosis (AVN) after total hip arthroplasty (THA) for non-traumatic AVN.

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Goker, Berna; Block, Joel A

2006-01-01

The risk of developing bilateral disease progressing to total hip arthroplasty (THA) among patients who undergo unilateral THA for non-traumatic avascular necrosis (AVN) remains poorly understood. An analysis of the time-course to contralateral THA, as well as the effects of underlying AVN risk factors, is presented. Forty-seven consecutive patients who underwent THA for AVN were evaluated. Peri-operative and annual post-operative antero-posterior pelvis radiographs were examined for evidence of contralateral involvement. Patient age, weight, height, underlying AVN risk factor(s), date of onset of contralateral hip pain if occurred, and date of contralateral THA if performed, were recorded. Bone scan, computerized tomography and magnetic resonance imaging data were utilized when available. Twenty-one patients (46.6%) underwent contralateral THA for AVN within a median of 9 months after the initial THA (range 0-93, interquartile range 28.5 months). The median follow-up for patients without contralateral THA was 75 months (range 3-109, interquartile range 69 months). Thirty-four patients had radiographic findings of contralateral AVN at study entry; 25 were symptomatic bilaterally at entry and 7 developed contralateral symptoms within a mean time of 12 months (median 10 months, interquartile range 12 months). None of the 13 patients who were free of radiographic evidence of contralateral AVN at study entry developed evidence of AVN during the follow-up. AVN associated with glucocorticoid use was more likely to manifest as bilateral disease than either idiopathic AVN or ethanol-associated AVN (P=0.02 and P=0.03 respectively). Radiographically-evident AVN in the contralateral hip at THA is unlikely to remain asymptomatic for a prolonged period of time. Conversely, asymptomatic contralateral hips without radiographic evidence of AVN are unlikely to develop clinically significant AVN.

Trigeminal-Rostral Ventromedial Medulla circuitry is involved in orofacial hyperalgesia contralateral to tissue injury

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Chai Bryan

2012-10-01

Full Text Available Abstract Background Our previous studies have shown that complete Freund’s adjuvant (CFA-induced masseter inflammation and microinjection of the pro-inflammatory cytokine interleukin-1β (IL-1β into the subnucleus interpolaris/subnucleus caudalis transition zone of the spinal trigeminal nucleus (Vi/Vc can induce contralateral orofacial hyperalgesia in rat models. We have also shown that contralateral hyperalgesia is attenuated with a lesion of the rostral ventromedial medulla (RVM, a critical site of descending pain modulation. Here we investigated the involvement of the RVM-Vi/Vc circuitry in mediating contralateral orofacial hyperalgesia after an injection of CFA into the masseter muscle. Results Microinjection of the IL-1 receptor antagonist (5 nmol, n=6 into the ipsilateral Vi/Vc attenuated the CFA-induced contralateral hyperalgesia but not the ipsilateral hyperalgesia. Intra-RVM post-treatment injection of the NK1 receptor antagonists, RP67580 (0.5-11.4 nmol and L-733,060 (0.5-11.4 nmol, attenuated CFA-induced bilateral hyperalgesia and IL-1β induced bilateral hyperalgesia. Serotonin depletion in RVM neurons prior to intra-masseter CFA injection prevented the development of contralateral hyperalgesia 1–3 days after CFA injection. Inhibition of 5-HT3 receptors in the contralateral Vi/Vc with direct microinjection of the select 5-HT3 receptor antagonist, Y-25130 (2.6-12.9 nmol, attenuated CFA-induced contralateral hyperalgesia. Lesions to the ipsilateral Vc prevented the development of ipsilateral hyperalgesia but did not prevent the development of contralateral hyperalgesia. Conclusions These results suggest that the development of CFA-induced contralateral orofacial hyperalgesia is mediated through descending facilitatory mechanisms of the RVM-Vi/Vc circuitry.

Clinical Significance of Contralateral Reactive Lesion in Vocal Fold Polyp and Cyst.

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Cho, Jung-Hae; Choi, Yong-Sug; Joo, Young-Hoon; Park, Young-Hak; Sun, Dong-Il

2018-01-01

We investigated the clinical significance of contralateral reactive lesions in patients undergoing laryngeal microsurgery for benign vocal fold lesions such as vocal polyps and cysts. This was a retrospective, single institution cohort study. Patient medical records were reviewed for demographic characteristics; acoustic, aerodynamic, and perceptual analyses; and Voice Handicap Index score before and after laryngeal microsurgery. Definitive diagnoses were made via intraoperative microlaryngoscopic evaluations. Clinical parameters were assessed to identify risk factors for contralateral reactive lesions. We evaluated surgical outcome using voice analysis. We enrolled 268 patients (109 men and 159 women) with benign vocal fold lesions. A total of 195 (72.8%) had a contralateral reactive vocal fold lesion. A multivariable analysis revealed that being a never smoker and having a hoarseness duration ≥6 months, vocal polyps, and small primary lesions were independent risk factors for contralateral reactive lesions (P vocal fold lesions are frequently detected in patients with vocal polyp and cyst. The reactive lesions had an adverse effect on voice quality. Simultaneous excision of primary and contralateral reactive lesions may be an alternative treatment for better voice outcome. Copyright © 2018 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

Simultaneous recordings from the primary visual cortex and lateral geniculate nucleus reveal rhythmic interactions and a cortical source for γ-band oscillations.

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Bastos, Andre M; Briggs, Farran; Alitto, Henry J; Mangun, George R; Usrey, W Martin

2014-05-28

Oscillatory synchronization of neuronal activity has been proposed as a mechanism to modulate effective connectivity between interacting neuronal populations. In the visual system, oscillations in the gamma-frequency range (30-100 Hz) are thought to subserve corticocortical communication. To test whether a similar mechanism might influence subcortical-cortical communication, we recorded local field potential activity from retinotopically aligned regions in the lateral geniculate nucleus (LGN) and primary visual cortex (V1) of alert macaque monkeys viewing stimuli known to produce strong cortical gamma-band oscillations. As predicted, we found robust gamma-band power in V1. In contrast, visual stimulation did not evoke gamma-band activity in the LGN. Interestingly, an analysis of oscillatory phase synchronization of LGN and V1 activity identified synchronization in the alpha (8-14 Hz) and beta (15-30 Hz) frequency bands. Further analysis of directed connectivity revealed that alpha-band interactions mediated corticogeniculate feedback processing, whereas beta-band interactions mediated geniculocortical feedforward processing. These results demonstrate that although the LGN and V1 display functional interactions in the lower frequency bands, gamma-band activity in the alert monkey is largely an emergent property of cortex. Copyright © 2014 the authors 0270-6474/14/347639-06$15.00/0.

Protection of the contralateral breast during radiation therapy for breast cancer

International Nuclear Information System (INIS)

Garrigo, E.; Zunino, S.; Germanier, A.

2008-01-01

Conformal Radiation Therapy (3DCRT) and Intensity Modulated Radiotherapy (IMRT) improve the relationship between tumor control and complications in normal tissue. However, these techniques may cause an increase of the normal tissue volume irradiated with low doses or an increase of the doses outside the beam. The aim of this work was to measure and compare the scatter dose to the contralateral breast using both the conventional two-field technique and the 3DCRT technique with blocks. The contralateral breast dose was measured with thermoluminescent dosimeters. The present work is divided in three parts: 1)Characterization of the radiation field outside the treatment beam; 2) Determination of the dose to the contralateral breast; 3) Design and construction of a shield to reduce the scatter dose to the contralateral breast. Treatment using 3DCRT technique was delivered to a phantom. From one to ten 2 mm thick lead sheets were placed on the dosimeters to attenuate radiation to the contralateral breast from the head, without blocking the treatment beam. Using the conventional technique the average dose to the contralateral breast was 2.09 Gy,4.18%(2.9%-19%) of the 50 Gy prescribed dose. The contribution of the medial field was 3.36% (2.3%-21.1%) and of the lateral field 0.86%(0.4%-3.7%). When using 3DCRT technique the average dose to the opposite breast was 5,9 Gy,11.8% (7.9%-24%) of the prescribed dose. The contribution of the medial field was 10.3% (6.7%-20%) and of the lateral field 1.6% (1.1%-3.8%). A 2 mm thick lead shield with a 0.2 g/cm2 thick wax coat was constructed which reduced the dose from 11.8% to less than 2%. The blocks increase the dose to the contralateral breast, the highest dose being attributed to the medial field. Our shield reduced the dose, which allowed the regular use of 3DCRT with blocks. In addition, we found that this shield was comfortable for the patients and easy to position for the therapists. (author)

MRI evaluation of the contralateral breast in patients with recently diagnosed breast cancer

International Nuclear Information System (INIS)

Taneja, Sangeeta; Jena, Amarnath; Zaidi, Syed Mohd. Shuaib; Khurana, Anuj

2012-01-01

Contralateral breast cancer can be synchronous and/or metachronous in patients with cancer of one breast. Detection of a synchronous breast cancer may affect patient management. Dynamic contrast-enhanced MRI of the breast (DCE-MRI) is a sensitive technique for detecting contralateral lesions occult on the other imaging modalities in women already diagnosed with cancer of one breast. The aim was to assess the incidence of mammographically occult synchronous contralateral breast cancer in patients undergoing MRI mammography for the evaluation of a malignant breast lesion. A total of 294 patients with recently diagnosed breast cancer who underwent MRI of the breast were evaluated for lesions in the opposite breast. The incidence of synchronous contralateral malignancy detected by preoperative MRI mammography done for evaluation of extent of disease was 4.1%. Preoperative breast MRI may detect clinically and mammographically occult synchronous contralateral cancer, and can help the patient avoid an additional second surgery or a second course of chemotherapy later; also, as theoretically these lesions are smaller, there may be a survival benefit as well

Evaluation of chest computed tomography in patients after pneumonectomy to predict contralateral pneumothorax

International Nuclear Information System (INIS)

Maniwa, Tomohiro; Saito, Yukihito; Saito, Tomohito; Kaneda, Hiroyuki; Imamura, Hiroji

2009-01-01

Contralateral pneumothorax is a severe complication after pneumonectomy. We evaluated the mediastinal shift and the residual lung in patients who had undergone pneumonectomy to predict the incidence of contralateral pneumothorax. We evaluated 21 cases of pneumonectomy performed from 1996 to 2006. For this study, we excluded patients with recurrent neoplasm, empyema, or hemothorax. We reviewed the computed tomography (CT) results of 13 patients who had undergone pneumonectomy to compare the bullae in the residual lungs, carina shifts, and herniation of the residual lungs before and after pneumonectomy. When evaluating the degree of herniation 4-6 cm below the carina, the anterior and posterior pulmonary hernias were classified as grade A, B, or C. We also investigated the preoperative respiratory function in all 13 patients. Two patients suffered contralateral pneumothorax after left pneumonectomy. Both patients who suffered contralateral pneumothorax after pneumonectomy had bullae. The percentage forced expiratory volume in 1 s (FEV 1.0% ) was <70% in these two patients. Carina shifts and lung herniation were found to be greater after left pneumonectomy than after right pneumonectomy. The bullae in the lung and obstructive pulmonary disease are associated not only with spontaneous pneumothorax but also with contralateral pneumothorax after pneumonectomy. Lung herniation and mediastinal shift are greater after left pneumonectomy than after right pneumonectomy, which may be related to contralateral pneumothorax after pneumonectomy. (author)

Latency modulation of collicular neurons induced by electric stimulation of the auditory cortex in Hipposideros pratti: In vivo intracellular recording.

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Kang Peng

Full Text Available In the auditory pathway, the inferior colliculus (IC receives and integrates excitatory and inhibitory inputs from the lower auditory nuclei, contralateral IC, and auditory cortex (AC, and then uploads these inputs to the thalamus and cortex. Meanwhile, the AC modulates the sound signal processing of IC neurons, including their latency (i.e., first-spike latency. Excitatory and inhibitory corticofugal projections to the IC may shorten and prolong the latency of IC neurons, respectively. However, the synaptic mechanisms underlying the corticofugal latency modulation of IC neurons remain unclear. Thus, this study probed these mechanisms via in vivo intracellular recording and acoustic and focal electric stimulation. The AC latency modulation of IC neurons is possibly mediated by pre-spike depolarization duration, pre-spike hyperpolarization duration, and spike onset time. This study suggests an effective strategy for the timing sequence determination of auditory information uploaded to the thalamus and cortex.

Simple shielding reduces dose to the contralateral breast during prone breast cancer radiotherapy

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Goyal, Uma, E-mail: uma.goyal@gmail.com; Locke, Angela; Smith-Raymond, Lexie; Georgiev, Georgi N.

2016-07-01

Our goal was to design a prone breast shield for the contralateral breast and study its efficacy in decreasing scatter radiation to the contralateral breast in a prone breast phantom setup receiving radiation therapy designed for breast cancer. We constructed a prone breast phantom setup consisting of (1) A thermoplastic mask with a left-sided depression created by a water balloon for a breast shape; (2) 2 plastic bags to hold water in the thermoplastic mask depression; (3) 2000 mL of water to fill the thermoplastic mask depression to create a water-based false breast; (4) 1-cm thick bolus placed in the contralateral breast holder; (5) 2 lead (Pb) sheets, each 0.1-cm thick for blocking scatter radiation in the contralateral bolus-based false breast; (6) a prone breast board to hold the thermoplastic mask, water, bolus, and lead; (7) 9 cm solid water on top of the breast board to simulate body; (8) a diode was used to verify dose for each treatment field of the treated water-based breast; (9) metal–oxide–semiconductor-field effect transistor (MOSFET) dosimeters to measure dose to the contralateral bolus-based breast. The phantom prone breast setup was CT simulated and treatment was designed with 95% isodose line covering the treated breast. The maximum dose was 107.1%. Megavoltage (MV) port images ensured accurate setup. Measurements were done using diodes on the treated water-based breast and MOSFET dosimeters at the medial and lateral sides of the contralateral bolus-based breast without and with the Pb shield. Five treatments were done for each of the 3 data sets and recorded individually for statistical purposes. All treatments were completed with 6 MV photons at 200 cGy per treatment. The dose contributions from each of the 3 data sets including 15 treatments total without and with the prone lead shield to the medial and lateral portions of contralateral bolus-based breast were averaged individually. Unshielded dose means were 37.11 and 2.94 cGy, and

Late development of cue integration is linked to sensory fusion in cortex.

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Dekker, Tessa M; Ban, Hiroshi; van der Velde, Bauke; Sereno, Martin I; Welchman, Andrew E; Nardini, Marko

2015-11-02

Adults optimize perceptual judgements by integrating different types of sensory information [1, 2]. This engages specialized neural circuits that fuse signals from the same [3-5] or different [6] modalities. Whereas young children can use sensory cues independently, adult-like precision gains from cue combination only emerge around ages 10 to 11 years [7-9]. Why does it take so long to make best use of sensory information? Existing data cannot distinguish whether this (1) reflects surprisingly late changes in sensory processing (sensory integration mechanisms in the brain are still developing) or (2) depends on post-perceptual changes (integration in sensory cortex is adult-like, but higher-level decision processes do not access the information) [10]. We tested visual depth cue integration in the developing brain to distinguish these possibilities. We presented children aged 6-12 years with displays depicting depth from binocular disparity and relative motion and made measurements using psychophysics, retinotopic mapping, and pattern classification fMRI. Older children (>10.5 years) showed clear evidence for sensory fusion in V3B, a visual area thought to integrate depth cues in the adult brain [3-5]. By contrast, in younger children (develop. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Percutaneous endoscopic lumbar discectomy via contralateral approach: a technical case report.

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Kim, Jin-Sung; Choi, Gun; Lee, Sang-Ho

2011-08-01

Technical case report. The authors report a new percutaneous endoscopic lumbar discectomy (PELD) technique for the treatment of lumbar disc herniation via a contralateral approach. When there are highly down-migrated lumbar disc herniation along just medial to pedicle and narrow ipsilateral intervertebral foramen, the conventional PELD is not easily accessible via ipsilateral transforaminal route. Five patients manifested gluteal and leg pain because of a soft disc herniation at the L4-L5 level. Transforaminal PELD via a contralateral approach was performed to remove the herniated fragment, achieving complete decompression of the nerve root. The symptom was relieved and the patient was discharged the next day. When a conventional transforaminal PELD is difficult because of some anatomical reasons, PELD via a contralateral route could be a good alternative option in selected cases.

Attention-related modulation of auditory brainstem responses during contralateral noise exposure.

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Ikeda, Kazunari; Sekiguchi, Takahiro; Hayashi, Akiko

2008-10-29

As determinants facilitating attention-related modulation of the auditory brainstem response (ABR), two experimental factors were examined: (i) auditory discrimination; and (ii) contralateral masking intensity. Tone pips at 80 dB sound pressure level were presented to the left ear via either single-tone exposures or oddball exposures, whereas white noise was delivered continuously to the right ear at variable intensities (none--80 dB sound pressure level). Participants each conducted two tasks during stimulation, either reading a book (ignoring task) or detecting target tones (attentive task). Task-related modulation within the ABR range was found only during oddball exposures at contralateral masking intensities greater than or equal to 60 dB. Attention-related modulation of ABR can thus be detected reliably during auditory discrimination under contralateral masking of sufficient intensity.

Figure-ground representation and its decay in primary visual cortex.

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Strother, Lars; Lavell, Cheryl; Vilis, Tutis

2012-04-01

We used fMRI to study figure-ground representation and its decay in primary visual cortex (V1). Human observers viewed a motion-defined figure that gradually became camouflaged by a cluttered background after it stopped moving. V1 showed positive fMRI responses corresponding to the moving figure and negative fMRI responses corresponding to the static background. This positive-negative delineation of V1 "figure" and "background" fMRI responses defined a retinotopically organized figure-ground representation that persisted after the figure stopped moving but eventually decayed. The temporal dynamics of V1 "figure" and "background" fMRI responses differed substantially. Positive "figure" responses continued to increase for several seconds after the figure stopped moving and remained elevated after the figure had disappeared. We propose that the sustained positive V1 "figure" fMRI responses reflected both persistent figure-ground representation and sustained attention to the location of the figure after its disappearance, as did subjects' reports of persistence. The decreasing "background" fMRI responses were relatively shorter-lived and less biased by spatial attention. Our results show that the transition from a vivid figure-ground percept to its disappearance corresponds to the concurrent decay of figure enhancement and background suppression in V1, both of which play a role in form-based perceptual memory.

Differential Recruitment of Parietal Cortex during Spatial and Non-spatial Reach Planning

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Pierre-Michel Bernier

2017-05-01

Full Text Available The planning of goal-directed arm reaching movements is associated with activity in the dorsal parieto-frontal cortex, within which multiple regions subserve the integration of arm- and target-related sensory signals to encode a motor goal. Surprisingly, many of these regions show sustained activity during reach preparation even when target location is not specified, i.e., when a motor goal cannot be unambiguously formed. The functional role of these non-spatial preparatory signals remains unresolved. Here this process was investigated in humans by comparing reach preparatory activity in the presence or absence of information regarding upcoming target location. In order to isolate the processes specific to reaching and to control for visuospatial attentional factors, the reaching task was contrasted to a finger movement task. Functional MRI and electroencephalography (EEG were used to characterize the spatio-temporal pattern of reach-related activity in the parieto-frontal cortex. Reach planning with advance knowledge of target location induced robust blood oxygenated level dependent and EEG responses across parietal and premotor regions contralateral to the reaching arm. In contrast, reach preparation without knowledge of target location was associated with a significant BOLD response bilaterally in the parietal cortex. Furthermore, EEG alpha- and beta-band activity was restricted to parietal scalp sites, the magnitude of the latter being correlated with reach reaction times. These results suggest an intermediate stage of sensorimotor transformations in bilateral parietal cortex when target location is not specified.

Magnetic resonance imaging at primary diagnosis cannot predict subsequent contralateral slip in slipped capital femoral epiphysis

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Wensaas, Anders [Akershus University Hospital, Department of Orthopaedic Surgery, Loerenskog (Norway); Wiig, Ola; Terjesen, Terje [Oslo University Hospital, Department of Orthopaedic Surgery, Rikshospitalet (Norway); Castberg Hellund, Johan; Khoshnewiszadeh, Behzad [Oslo University Hospital, Department of Radiology and Nuclear Medicine, Ullevaal (Norway)

2017-12-15

Prophylactic fixation of the contralateral hip in slipped capital femoral epiphysis (SCFE) is controversial, and no reliable method has been established to predict subsequent contralateral slip. The main purpose of this study was to evaluate if magnetic resonance imaging (MRI) performed at primary diagnosis could predict future contralateral slip. Twenty-two patients with unilateral SCFE were included, all had MRI of both hips taken before operative fixation. Six different parameters were measured on the MRI: the MRI slip angle, the greatest focal widening of the physis, the global widening of the physis measured at three locations (the midpoint of the physis and 1 cm lateral and medial to the midpoint), periphyseal (epiphyseal and metaphyseal) bone marrow edema, the presence of pathological joint effusion, and the amount of joint effusion measured from the lateral edge of the greater trochanter. Mean follow-up was 33 months (range, 16-63 months). Six patients were treated for contralateral slip during the follow-up time and a comparison of the MRI parameters of the contralateral hip in these six patients and in the 16 patients that remained unilateral was done to see if subsequent contralateral slip was possible to predict at primary diagnosis. All MRI parameters were significantly altered in hips with established SCFE compared with the contralateral hips. However, none of the MRI parameters showed any significant difference between patients who had a subsequent contralateral slip and those that remained unilateral. MRI taken at primary diagnosis could not predict future contralateral slip. (orig.)

Negative BOLD signal changes in ipsilateral primary somatosensory cortex are associated with perfusion decreases and behavioral evidence for functional inhibition

DEFF Research Database (Denmark)

Schäfer, Katharina; Blankenburg, Felix; Kupers, Ron

2012-01-01

that the negative BOLD signal is associated with functional inhibition. Electrical stimulation of the median nerve at 7Hz evoked robust negative BOLD signals in the primary somatosensory cortex (SI) ipsilateral to stimulation, and positive BOLD signals in contralateral SI. The negative BOLD signal in ipsilateral SI......) at the ipsilateral finger during concomitant stimulation of the contralateral median nerve increased significantly, suggesting augmented functional inhibition. Since the CPT in the ipsilateral hallux did not significantly change in response to median nerve stimulation, it is more likely that the CPT......-increase for the finger is due to functional inhibition (Kastrup et al., 2008) than to changes in selective attention. In conclusion, our data provide evidence that stimulus-induced reductions in relative rCBF may underlie the negative BOLD signal, which in turn may reflect increments in functional inhibition....

Contralateral breast cancer and other second malignancies in patients treated by breast-conserving therapy with radiation

International Nuclear Information System (INIS)

Kurtz, J.M.; Amalric, R.; Brandone, H.; Ayme, Y.; Spitalier, J.M.

1988-01-01

Metachronous contralateral breast cancers and other second malignancies were evaluated in 2,850 patients treated between 1960 and 1981 primarily with radiotherapy (RT) either alone or following breast-conserving surgery. One hundred eighty-four contralateral cancers were observed in 22,491 patient-years of observation (818 per 10(5) patient-years), with a cumulative probability of 4.5% at 5, 7.9% at 10, and 11% at 15 and 20 years. Compared to patients with unilateral tumors, those destined to develop contralateral cancers were younger (mean age 51.9 vs 56.6) and more often gave a family history of breast cancer. Contralateral breast cancers were more frequent for more extensive tumors (T3 10% vs T1-26%; with inflammatory signs 10.6% without 6%), and in patients with ipsilateral local recurrence (with 9.1%, without 5.6%). Patients with contralateral cancers had a significantly less favorable survival experience (15-year actuarial survival after primary therapy 42%) than patients without contralateral cancer (15-year survival 65.5%). In early stage patients treated with conservative surgery and RT, contralateral cancer was not prognostically more favorable than ipsilateral breast recurrence. Among 72 other second malignancies (320 per 10(5) patient-years) were 2 soft tissue sarcomas in the irradiated area. This corresponds to an incidence of 21 cases per 10(5) patient-years for survivors beyond the fifth year. The possible influence of RT on contralateral cancers and other second malignancies is discussed

Motor demand-dependent activation of ipsilateral motor cortex.

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Buetefisch, Cathrin M; Revill, Kate Pirog; Shuster, Linda; Hines, Benjamin; Parsons, Michael

2014-08-15

The role of ipsilateral primary motor cortex (M1) in hand motor control during complex task performance remains controversial. Bilateral M1 activation is inconsistently observed in functional (f)MRI studies of unilateral hand performance. Two factors limit the interpretation of these data. As the motor tasks differ qualitatively in these studies, it is conceivable that M1 contributions differ with the demand on skillfulness. Second, most studies lack the verification of a strictly unilateral execution of the motor task during the acquisition of imaging data. Here, we use fMRI to determine whether ipsilateral M1 activity depends on the demand for precision in a pointing task where precision varied quantitatively while movement trajectories remained equal. Thirteen healthy participants used an MRI-compatible joystick to point to targets of four different sizes in a block design. A clustered acquisition technique allowed simultaneous fMRI/EMG data collection and confirmed that movements were strictly unilateral. Accuracy of performance increased with target size. Overall, the pointing task revealed activation in contralateral and ipsilateral M1, extending into contralateral somatosensory and parietal areas. Target size-dependent activation differences were found in ipsilateral M1 extending into the temporal/parietal junction, where activation increased with increasing demand on accuracy. The results suggest that ipsilateral M1 is active during the execution of a unilateral motor task and that its activity is modulated by the demand on precision. Copyright © 2014 the American Physiological Society.

A re-examination of Hebbian-covariance rules and spike timing-dependent plasticity in cat visual cortex in vivo

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Yves Frégnac

2010-12-01

Full Text Available Spike-Timing-Dependent Plasticity (STDP is considered as an ubiquitous rule for associative plasticity in cortical networks in vitro. However, limited supporting evidence for its functional role has been provided in vivo. In particular, there are very few studies demonstrating the co-occurence of synaptic efficiency changes and alteration of sensory responses in adult cortex during Hebbian or STDP protocols. We addressed this issue by reviewing and comparing the functional effects of two types of cellular conditioning in cat visual cortex. The first one, referred to as the covariance protocol, obeys a generalized Hebbian framework, by imposing, for different stimuli, supervised positive and negative changes in covariance between postsynaptic and presynaptic activity rates. The second protocol, based on intracellular recordings, replicated in vivo variants of the theta-burst paradigm (TBS, proven successful in inducing long-term potentiation (LTP in vitro. Since it was shown to impose a precise correlation delay between the electrically activated thalamic input and the TBS-induced postsynaptic spike, this protocol can be seen as a probe of causal (pre-before-post STDP. By choosing a thalamic region where the visual field representation was in retinotopic overlap with the intracellularly recorded cortical receptive field as the afferent site for supervised electrical stimulation, this protocol allowed to look for possible correlates between STDP and functional reorganization of the conditioned cortical receptive field. The rate-based covariance protocol induced significant and large amplitude changes in receptive field properties, in both kitten and adult V1 cortex. The TBS STDP-like protocol produced in the adult significant changes in the synaptic gain of the electrically activated thalamic pathway, but the statistical significance of the functional correlates was detectable mostly at the population level. Comparison of our observations with the

Women's preferences for contralateral prophylactic mastectomy: An investigation using protection motivation theory.

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Tesson, Stephanie; Richards, Imogen; Porter, David; Phillips, Kelly-Anne; Rankin, Nicole; Musiello, Toni; Marven, Michelle; Butow, Phyllis

2016-05-01

Most women diagnosed with unilateral breast cancer without BRCA1 or BRCA2 mutations are at low risk of contralateral breast cancer. Contralateral Prophylactic Mastectomy (CPM) decreases the relative risk of contralateral breast cancer, but may not increase life expectancy; yet international uptake is increasing. This study applied protection motivation theory (PMT) to determine factors associated with women's intentions to undergo CPM. Three hundred eighty-eight women previously diagnosed with unilateral breast cancer and of negative or unknown BRCA1 or BRCA2 status were recruited from an advocacy group's research database. Participants completed measures of PMT constructs based on a common hypothetical CPM decision-making scenario. PMT constructs explained 16% of variance in intentions to undergo CPM. Response efficacy (CPM's advantages) and response costs (CPM's disadvantages) were unique individual predictors of intentions. Decision-making appears driven by considerations of the psychological, cosmetic and emotional advantages and disadvantages of CPM. Overestimations of threat to life from contralateral breast cancer and survival benefit from CPM also appear influential factors. Patients require balanced and medically accurate information regarding the pros and cons of CPM, survival rates, and recurrence risks to ensure realistic and informed decision-making.

Anterior cingulate cortex is crucial for contra- but not ipsi-lateral electro-acupuncture in the formalin-induced inflammatory pain model of rats

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Xing Guo-Gang

2011-08-01

Full Text Available Abstract Acupuncture and electro-acupuncture (EA are now widely used to treat disorders like pain. We and others have shown previously that current frequency, intensity and treatment duration all significantly influence the anti-nociceptive effects of EA. There is evidence that stimulating sites also affect the antinociception, with EA applied ipsilaterally to the pain site being more effective under some pain states but contralateral EA under others. It was recently reported that local adenosine A1 receptors were responsible for ipsilateral acupuncture, but what mechanisms specifically mediate the anti-nociceptive effects of contralateral acupuncture or EA remains unclear. In the present study, we applied 100 Hz EA on the ipsi- or contra-lateral side of rats with inflammatory pain induced by intra-plantar injection of formalin, and reported distinct anti-nociceptive effects and mechanisms between them. Both ipsi- and contra-lateral EA reduced the paw lifting time in the second phase of the formalin test and attenuated formalin-induced conditioned place aversion. Contralateral EA had an additional effect of reducing paw licking time, suggesting a supraspinal mechanism. Lesions of rostral anterior cingulate cortex (ACC completely abolished the anti-nociceptive effects of contra- but not ipsi-lateral EA. These findings were not lateralized effects, since injection of formalin into the left or right hind paws produced similar results. Overall, these results demonstrated distinct anti-nociceptive effects and mechanisms between different stimulating sides and implied the necessity of finding the best stimulating protocols for different pain states.

Lower layers in the motor cortex are more effective targets for penetrating microelectrodes in cortical prostheses

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Parikh, Hirak; Marzullo, Timothy C.; Kipke, Daryl R.

2009-04-01

Improving cortical prostheses requires the development of recording neural interfaces that are efficient in terms of providing maximal control information with minimal interface complexity. While the typical approaches have targeted neurons in the motor cortex with multiple penetrating shanks, an alternative approach is to determine an efficient distribution of electrode sites within the layers of the cortex with fewer penetrating shanks. The objective of this study was to compare unit activity in the upper and lower layers of the cortex with respect to movement and direction in order to inform the design of penetrating microelectrodes. Four rats were implanted bilaterally with multi-site single-shank silicon microelectrode arrays in the neck/shoulder region of the motor cortex. We simultaneously recorded unit activity across all layers of the motor cortex while the animal was engaged in a movement direction task. Localization of the electrode array within the different layers of the cortex was determined by histology. We denoted units from layers 2 and 3 and units as upper layer units, and units from layers 5 and 6 as lower layer units. Analysis of unit spiking activity demonstrated that both the upper and lower layers encode movement and direction information. Unit responses in either cortical layer of the cortex were not preferentially associated with contralateral or ipsilateral movement. Aggregate analysis (633 neurons) and best session analysis (75 neurons) indicated that units in the lower layers (layers 5, 6) are more likely to encode direction information when compared to units in the upper layers (layers 2, 3) (p< 0.05). These results suggest that electrode sites clustered in the lower layers provide access to more salient control information for cortical neuroprostheses.

Predictors of contralateral prophylactic mastectomy and the impact on breast reconstruction.

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Pinell-White, Ximena A; Kolegraff, Keli; Carlson, Grant W

2014-01-01

Contralateral prophylactic mastectomy (CPM) is being performed with increased frequency. Predictors of CPM and their impact on breast reconstruction are examined. A retrospective review of a dually trained oncologic and plastic surgeon's experience with patients undergoing total mastectomy from 2002 to 2012 was performed. Patients who underwent bilateral therapeutic mastectomies or who had previous contralateral mastectomy were excluded from this series. Four hundred forty-six patients were treated with total mastectomy and 174 (39%) underwent CPM. The incidence of CPM nearly tripled over the period studied. Compared to women treated with unilateral mastectomy, women who elected for CPM were younger (mean age, 50.4 vs 56.8 years, P mastectomy. Incidental contralateral cancers were discovered in 4% of women who underwent CPM (n = 7), lobular carcinoma in situ in 2.3% (n = 4), and atypical lesions in an additional 11.6% (n = 20). Women who underwent CPM favored reconstruction with breast implants (60.9% vs 17.3%), whereas the transverse rectus abdominis musculocutaneous flap predominated among their unilateral counterparts (38.6% vs 15.5%). Among women who underwent immediate breast reconstruction, the addition of a contralateral procedure expectedly increased breast complication rates (50.3% vs 35.0%, P = 0.007), especially the more severe complications that required hospitalization or reoperation (18.6% vs 5.0%, P procedure is significant.

Ultrasound screening of contralateral breast after surgery for breast cancer

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Kim, Seung Ja [Department of Radiology, Seoul Metropolitan Government Seoul National University, Boramae Medical Center (Korea, Republic of); Chung, Se-Yeong; Chang, Jung Min; Cho, Nariya [Department of Radiology, Seoul National University Hospital (Korea, Republic of); Han, Wonshik [Department of Surgery, Seoul National University Hospital (Korea, Republic of); Moon, Woo Kyung, E-mail: moonwk@snu.ac.kr [Department of Radiology, Seoul National University Hospital (Korea, Republic of)

2015-01-15

Highlights: • The addition of supplemental US to mammography depicted additional 5.0 cancers per 1000 postoperative women. • Positive biopsy rate of mammography-detected lesions was 66.7% (4 of 6) and that of US-detected lesions was 40.0% (6 of 15). • US can be helpful to detect mammographically occult breast cancer in the contralateral breast in women with previous history of cancer and dense breast. - Abstract: Objective: To determine whether supplemental screening ultrasound (US) to mammography could improve cancer detection rate of the contralateral breast in patients with a personal history of breast cancer and dense breasts. Materials and methods: During a one-year study period, 1314 screening patients with a personal history of breast cancer and dense breasts simultaneously underwent mammography and breast US. BI-RADS categories were given for mammography or US-detected lesions in the contralateral breast. The reference standard was histology and/or 1-year imaging follow-up, and the cancer rate according to BI-RADS categories and cancer detection rate and positive biopsy rate according to detection modality were analyzed. Results: Of 1314 patients, 84 patients (6.4%) were categorized as category 3 with one interval cancer and one cancer which was upgraded to category 4A after 6-month follow-up US (2.5% cancer rate, 95% CIs 1.5–9.1%). Fifteen patients (1.1%) had category 4A or 4B lesions in the contralateral breast. Four lesions were detected on mammography (two lesions were also visible on US) and 11 lesions were detected on US and 5 cancers were confirmed (33.3%, 95% CIs 15.0–58.5%). Six patients (0.5%) had category 4C lesions, 2 detected on mammography and 4 on US and 4 cancers were confirmed (66.7%, 95% CIs 29.6–90.8%). No lesions were categorized as category 5 in the contralateral breast. Cancer detection rate by mammography was 3.3 per 1000 patients and that by US was 5.0 per 1000 patients, therefore overall cancer detection rate by

Ultrasound screening of contralateral breast after surgery for breast cancer

International Nuclear Information System (INIS)

Kim, Seung Ja; Chung, Se-Yeong; Chang, Jung Min; Cho, Nariya; Han, Wonshik; Moon, Woo Kyung

2015-01-01

Highlights: • The addition of supplemental US to mammography depicted additional 5.0 cancers per 1000 postoperative women. • Positive biopsy rate of mammography-detected lesions was 66.7% (4 of 6) and that of US-detected lesions was 40.0% (6 of 15). • US can be helpful to detect mammographically occult breast cancer in the contralateral breast in women with previous history of cancer and dense breast. - Abstract: Objective: To determine whether supplemental screening ultrasound (US) to mammography could improve cancer detection rate of the contralateral breast in patients with a personal history of breast cancer and dense breasts. Materials and methods: During a one-year study period, 1314 screening patients with a personal history of breast cancer and dense breasts simultaneously underwent mammography and breast US. BI-RADS categories were given for mammography or US-detected lesions in the contralateral breast. The reference standard was histology and/or 1-year imaging follow-up, and the cancer rate according to BI-RADS categories and cancer detection rate and positive biopsy rate according to detection modality were analyzed. Results: Of 1314 patients, 84 patients (6.4%) were categorized as category 3 with one interval cancer and one cancer which was upgraded to category 4A after 6-month follow-up US (2.5% cancer rate, 95% CIs 1.5–9.1%). Fifteen patients (1.1%) had category 4A or 4B lesions in the contralateral breast. Four lesions were detected on mammography (two lesions were also visible on US) and 11 lesions were detected on US and 5 cancers were confirmed (33.3%, 95% CIs 15.0–58.5%). Six patients (0.5%) had category 4C lesions, 2 detected on mammography and 4 on US and 4 cancers were confirmed (66.7%, 95% CIs 29.6–90.8%). No lesions were categorized as category 5 in the contralateral breast. Cancer detection rate by mammography was 3.3 per 1000 patients and that by US was 5.0 per 1000 patients, therefore overall cancer detection rate by

Motor Cortex Activity During Functional Motor Skills: An fNIRS Study.

Science.gov (United States)

Nishiyori, Ryota; Bisconti, Silvia; Ulrich, Beverly

2016-01-01

Assessments of brain activity during motor task performance have been limited to fine motor movements due to technological constraints presented by traditional neuroimaging techniques, such as functional magnetic resonance imaging. Functional near-infrared spectroscopy (fNIRS) offers a promising method by which to overcome these constraints and investigate motor performance of functional motor tasks. The current study used fNIRS to quantify hemodynamic responses within the primary motor cortex in twelve healthy adults as they performed unimanual right, unimanual left, and bimanual reaching, and stepping in place. Results revealed that during both unimanual reaching tasks, the contralateral hemisphere showed significant activation in channels located approximately 3 cm medial to the C3 (for right-hand reach) and C4 (for left-hand reach) landmarks. Bimanual reaching and stepping showed activation in similar channels, which were located bilaterally across the primary motor cortex. The medial channels, surrounding Cz, showed significantly higher activations during stepping when compared to bimanual reaching. Our results extend the viability of fNIRS to study motor function and build a foundation for future investigation of motor development in infants during nascent functional behaviors and monitor how they may change with age or practice.

The activity of the primary motor cortex ipsilateral to the exercising hand decreases during repetitive handgrip exercise

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Shibuya, Kenichi

2011-01-01

The brain function controlling muscle force production is not yet fully understood. The purpose of this study was to examine bilateral primary motor cortex (M1) oxygenation during static-handgrip exercises performed with the right hand (60% maximal voluntary contraction; 10 s exercise/75 s rest; five sets). Twelve healthy, right-handed male subjects participated in this study. Near-infrared spectroscopy probes were positioned over the bilateral M1 to measure cortical oxygenation during handgrip exercises. The maximum values of the changes in concentrations of oxyhemoglobin (HbO 2 ) and deoxyhemoglobin (Hb) across the trials (i) did not change significantly during the contralateral M1 activation (p > 0.05), whereas (ii) in the case of the ipsilateral M1 activation a significant (p < 0.05) decrease in HbO 2 and a significant (p < 0.01) decrease in Hb could be measured. The activation in ipsilateral M1 at the fifth trial was significantly decreased compared with that in the first trial (HbO 2 : p < 0.001; Hb: p < 0.001). The present results suggest that the ipsilateral M1 is recruited during the motor task in compensation for the contralateral M1 and the habituation to motor task might alter the efficiency for interaction of the ipsilateral M1 to the contralateral M1. The interhemispheric interaction might change due to habituation to motor task

Regional structural differences across functionally parcellated Brodmann areas of human primary somatosensory cortex.

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Sánchez-Panchuelo, Rosa-María; Besle, Julien; Mougin, Olivier; Gowland, Penny; Bowtell, Richard; Schluppeck, Denis; Francis, Susan

2014-06-01

Ultra-high-field (UHF) MRI is ideally suited for structural and functional imaging of the brain. High-resolution structural MRI can be used to map the anatomical boundaries between functional domains of the brain by identifying changes related to the pattern of myelination within cortical gray matter, opening up the possibility to study the relationship between functional domains and underlying structure in vivo. In a recent study, we demonstrated the correspondence between functional (based on retinotopic mapping) and structural (based on changes in T2(⁎)-weighted images linked to myelination) parcellations of the primary visual cortex (V1) in vivo at 7T (Sanchez-Panchuelo et al., 2012b). Here, we take advantage of the improved BOLD CNR and high spatial resolution achievable at 7T to study regional structural variations across the functionally defined areas within the primary somatosensory cortex (S1) in individual subjects. Using a traveling wave fMRI paradigm to map the internal somatotopic representation of the index, middle, and ring fingers in S1, we were able to identify multiple map reversals at the tip and base, corresponding to the boundaries between Brodmann areas 3a, 3b, 1 and 2. Based on high resolution structural MRI data acquired in the same subjects, we inspected these functionally-parcellated Brodmann areas for differences in cortical thickness and MR contrast measures (magnetization transfer ratio (MTR) and signal intensity in phase sensitive inversion recovery (PSIR) images) that are sensitive to myelination. Consistent area-related differences in cortical thickness and MTR/PSIR measurements were found across subjects. However these measures did not have sufficient sensitivity to allow definition of areal boundaries. Copyright © 2013 Elsevier Inc. All rights reserved.

Corticothalamic and corticotectal somatosensory projections from the anterior ectosylvian sulcus (SIV cortex) in neonatal cats: an anatomical demonstration with HRP and 3H-leucine

International Nuclear Information System (INIS)

McHaffie, J.G.; Kruger, L.; Clemo, H.R.; Stein, B.E.

1988-01-01

Corticothalamic and corticotectal projections from the anterior ectosylvian sulcus (AES) in neonatal cats were studied with anterograde and retrograde neuroanatomical techniques. When the injection site was relatively restricted to the sulcal walls and fundus of the rostral AES (i.e., the SIV cortex), heavy ipsilateral thalamic label was observed in the medial subdivision of the posterior group, in the suprageniculate nucleus, and in the external medullary lamina. No terminal label was seen in the contralateral thalamus although the contralateral homotopic cortex was heavily labeled. Within the ventrobasal complex (VB), dense axonal label was observed in fascicles that traversed VB, but only light terminal label was observed within VB itself. However, in cases where the tracer spread into adjacent SII, terminal label in VB was pronounced. Similarly, when the injection site extended into auditory cortex, terminal label was observed in the lateral and intermediate subdivisions of the posterior group. Rostral AES injections produced distinct, predominantly ipsilateral, terminal label in the superior colliculus that was distributed in two tiers: a discontinuous band in the stratum griseum intermedium and a more diffuse band in stratum griseum profundum. Caudally, dense terminal label was seen in the intercollicular zone and dorsolateral periaqueductal gray. When the injection site did not include rostral AES, no label was observed in the superior colliculus. Horseradish peroxidase injections into the superior colliculus of neonates produced retrogradely labeled neurons throughout the AES, but none was found on the crown of the gyrus where SII is located. Thus, the neonatal corticotectal somatosensory projection arises exclusively from AES and parallels that found in adults

Left auditory cortex is involved in pairwise comparisons of the direction of frequency modulated tones

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Nicole eAngenstein

2013-07-01

Full Text Available Evaluating series of complex sounds like those in speech and music requires sequential comparisons to extract task-relevant relations between subsequent sounds. With the present functional magnetic resonance imaging (fMRI study, we investigated whether sequential comparison of a specific acoustic feature within pairs of tones leads to a change in lateralized processing in the auditory cortex of humans. For this we used the active categorization of the direction (up versus down of slow frequency modulated (FM tones. Several studies suggest that this task is mainly processed in the right auditory cortex. These studies, however, tested only the categorization of the FM direction of each individual tone. In the present study we ask the question whether the right lateralized processing changes when, in addition, the FM direction is compared within pairs of successive tones. For this we use an experimental approach involving contralateral noise presentation in order to explore the contributions made by the left and right auditory cortex in the completion of the auditory task. This method has already been applied to confirm the right-lateralized processing of the FM direction of individual tones. In the present study, the subjects were required to perform, in addition, a sequential comparison of the FM-direction in pairs of tones. The results suggest a division of labor between the two hemispheres such that the FM direction of each individual tone is mainly processed in the right auditory cortex whereas the sequential comparison of this feature between tones in a pair is probably performed in the left auditory cortex.

Functional rearrangement of the primary and secondary motor cortex in patients with primary tumors of the central nervous system located in the region of the central sulcus depending on the histopathological type and the size of tumor: Examination by means of functional magnetic resonance imaging

International Nuclear Information System (INIS)

Bryszewski, Bartosz; Pfajfer, Lucjan; Antosik-Biernacka, Aneta; Tybor, Krzysztof; Śmigielski, Janusz; Zawirski, Marek; Majos, Agata

2012-01-01

The aim of this study was to analyze the reorganization of the centers of the motor cortex in patients with primary neuroepithelial tumors of the central nervous system (CNS) located in the region of the central sulcus in relation to the histopathological type and the size of tumor, as determined by means of functional magnetic resonance imaging (fMRI). The fMRI was performed prior to the surgical treatment of patients with tumors located in the region of the central sulcus (WHO stage I and II, n=15; WHO stage III and IV, n=25). The analysis included a record of the activity in the areas of the primary motor cortex (M1) and the secondary motor cortex: the premotor cortex (PMA) and the accessory motor area (SMA). The results were correlated with the histopathological type of the tumor and its size expressed in cm 3 . The frequency of activation of the motor center was higher in the group of patients who had less aggressive tumors, such as low-grade glioma (LGG), as well as in tumors of lower volume, and this was true both for the hemisphere where the tumor was located and in the contralateral one. Mean values of t-statistics of activation intensity, mean numbers of activated clusters, and their ranges were lower in all analyzed motor areas of LGG tumors. The values of t-statistics and activation areas were higher in the case of small tumors located in ipsilateral centers, and in large tumors located in contralateral centers, aside from the SMA area where the values of t-statistics were equal for both groups. The contralateral SMA area was characterized by the highest stability of all examined centers of secondary motor cortex. No significant association (p>0.05) was observed between the absolute value of the mean registered activity (t-statistics) and the size of examined areas (number of clusters) when the groups were stratified with regards to the analyzed parameters. The presence of a neoplastic lesion, its histopathological type and finally its size modulate the

Region and task-specific activation of Arc in primary motor cortex of rats following motor skill learning.

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Hosp, J A; Mann, S; Wegenast-Braun, B M; Calhoun, M E; Luft, A R

2013-10-10

Motor learning requires protein synthesis within the primary motor cortex (M1). Here, we show that the immediate early gene Arc/Arg3.1 is specifically induced in M1 by learning a motor skill. Arc mRNA was quantified using a fluorescent in situ hybridization assay in adult Long-Evans rats learning a skilled reaching task (SRT), in rats performing reaching-like forelimb movement without learning (ACT) and in rats that were trained in the operant but not the motor elements of the task (controls). Apart from M1, Arc expression was assessed within the rostral motor area (RMA), primary somatosensory cortex (S1), striatum (ST) and cerebellum. In SRT animals, Arc mRNA levels in M1 contralateral to the trained limb were 31% higher than ipsilateral (pmotor skill learning in rats. Copyright © 2013 IBRO. Published by Elsevier Ltd. All rights reserved.

Effects of contralateral noise on the 20-Hz auditory steady state response--magnetoencephalography study.

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Hajime Usubuchi

Full Text Available The auditory steady state response (ASSR is an oscillatory brain response, which is phase locked to the rhythm of an auditory stimulus. ASSRs have been recorded in response to a wide frequency range of modulation and/or repetition, but the physiological features of the ASSRs are somewhat different depending on the modulation frequency. Recently, the 20-Hz ASSR has been emphasized in clinical examinations, especially in the area of psychiatry. However, little is known about the physiological properties of the 20-Hz ASSR, compared to those of the 40-Hz and 80-Hz ASSRs. The effects of contralateral noise on the ASSR are known to depend on the modulation frequency to evoke ASSR. However, the effects of contralateral noise on the 20-Hz ASSR are not known. Here we assessed the effects of contralateral white noise at a level of 70 dB SPL on the 20-Hz and 40-Hz ASSRs using a helmet-shaped magnetoencephalography system in 9 healthy volunteers (8 males and 1 female, mean age 31.2 years. The ASSRs were elicited by monaural 1000-Hz 5-s tone bursts amplitude-modulated at 20 and 39 Hz and presented at 80 dB SPL. Contralateral noise caused significant suppression of both the 20-Hz and 40-Hz ASSRs, although suppression was significantly smaller for the 20-Hz ASSRs than the 40-Hz ASSRs. Moreover, the greatest suppression of both 20-Hz and 40-Hz ASSRs occurred in the right hemisphere when stimuli were presented to the right ear with contralateral noise. The present study newly showed that 20-Hz ASSRs are suppressed by contralateral noise, which may be important both for characterization of the 20-Hz ASSR and for interpretation in clinical situations. Physicians must be aware that the 20-Hz ASSR is significantly suppressed by sound (e.g. masking noise or binaural stimulation applied to the contralateral ear.

Evidence for cue-independent spatial representation in the human auditory cortex during active listening.

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Higgins, Nathan C; McLaughlin, Susan A; Rinne, Teemu; Stecker, G Christopher

2017-09-05

Few auditory functions are as important or as universal as the capacity for auditory spatial awareness (e.g., sound localization). That ability relies on sensitivity to acoustical cues-particularly interaural time and level differences (ITD and ILD)-that correlate with sound-source locations. Under nonspatial listening conditions, cortical sensitivity to ITD and ILD takes the form of broad contralaterally dominated response functions. It is unknown, however, whether that sensitivity reflects representations of the specific physical cues or a higher-order representation of auditory space (i.e., integrated cue processing), nor is it known whether responses to spatial cues are modulated by active spatial listening. To investigate, sensitivity to parametrically varied ITD or ILD cues was measured using fMRI during spatial and nonspatial listening tasks. Task type varied across blocks where targets were presented in one of three dimensions: auditory location, pitch, or visual brightness. Task effects were localized primarily to lateral posterior superior temporal gyrus (pSTG) and modulated binaural-cue response functions differently in the two hemispheres. Active spatial listening (location tasks) enhanced both contralateral and ipsilateral responses in the right hemisphere but maintained or enhanced contralateral dominance in the left hemisphere. Two observations suggest integrated processing of ITD and ILD. First, overlapping regions in medial pSTG exhibited significant sensitivity to both cues. Second, successful classification of multivoxel patterns was observed for both cue types and-critically-for cross-cue classification. Together, these results suggest a higher-order representation of auditory space in the human auditory cortex that at least partly integrates the specific underlying cues.

Surround inhibition in the primary motor cortex is task-specifically modulated in non-professional musicians but not in healthy controls during real piano playing

DEFF Research Database (Denmark)

Márquez, Gonzalo; Keller, Martin; Lundbye-Jensen, Jesper

2018-01-01

participants. Transcranial magnetic stimulation (TMS) was applied to the contralateral motor cortex to assess SI in the first dorsal interosseous (FDI), abductor pollicis brevis (APB) and abductor digiti minimi (ADM) during the movement preparation and the late phasic phases. The results reveal stronger SI...... that long-term training as observed in skilled musicians is accompanied by task-specific effects on SI modulation potentially relating to the ability to perform selective and complex finger movements....

Contralateral Total Hip Arthroplasty After Hindquarter Amputation

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Scott M. M. Sommerville

2006-01-01

Full Text Available We describe the management and outcome of a 62-year old lady who developed severe osteoarthritis of the hip, nine years after a hindquarter amputation for radiation-induced sarcoma of the contralateral pelvis. The difficulties of stabilising the pelvis intraoperatively and the problems of postoperative rehabilitation are outlined. The operation successfully relieved her pain and restored limited mobility.

Contralateral Fracture of the Penis with Concomitant Urethral Injury ...

African Journals Online (AJOL)

ra

2009-03-16

Mar 16, 2009 ... 2, 2009. 103. 103-106. Case Report. Contralateral Fracture of the Penis with Concomitant. Urethral ... Examination revealed ecchymosis and swelling of the proximal shaft and ... of impotence due to infection and cavernosal.

Poor WOMAC scores in contralateral knee negatively impact TKA outcomes: data from the osteoarthritis initiative.

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Kahn, Timothy L; Soheili, Aydin C; Schwarzkopf, Ran

2014-08-01

While total knee arthroplasty (TKA) has been shown to have excellent outcomes, a significant proportion of patients experience relatively poor post-operative function. In this study, we test the hypothesis that the level of osteoarthritic symptoms in the contralateral knee at the time of TKA is associated with poorer post-operative outcomes in the operated knee. Using longitudinal cohort data from the Osteoarthritis Initiative (OAI), we included 171 patients who received a unilateral TKA. We compared pre-operative Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores in the contralateral knee to post-operative WOMAC scores in the index knee. Pre-operative contralateral knee WOMAC scores were associated with post-operative index knee WOMAC Total scores, indicating that the health of the pre-operative contralateral knee is a significant factor in TKA outcomes. Copyright © 2014 Elsevier Inc. All rights reserved.

Screening for carcinoma in situ of the contralateral testis in patients with germinal testicular cancer

DEFF Research Database (Denmark)

Berthelsen, J G; Skakkebaek, N E; von der Maase, H

1982-01-01

Two hundred and fifty biopsy specimens from the contralateral testis in patients with unilateral germinal testicular cancer were analysed by light microscopy for carcinoma-in-situ changes. Changes were found in 13 (5.2%) patients. One-third of patients with an atrophic contralateral testis (volume...... of cryptorchidism or both had been screened. Since the natural course of carcinoma in situ in the contralateral testis of patients with germinal testicular cancer has not been established, the patients are being re-evaluated frequently. To date two patients with carcinoma in situ have developed a second cancer....

Representation of dynamic interaural phase difference in auditory cortex of awake rhesus macaques.

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Scott, Brian H; Malone, Brian J; Semple, Malcolm N

2009-04-01

Neurons in auditory cortex of awake primates are selective for the spatial location of a sound source, yet the neural representation of the binaural cues that underlie this tuning remains undefined. We examined this representation in 283 single neurons across the low-frequency auditory core in alert macaques, trained to discriminate binaural cues for sound azimuth. In response to binaural beat stimuli, which mimic acoustic motion by modulating the relative phase of a tone at the two ears, these neurons robustly modulate their discharge rate in response to this directional cue. In accordance with prior studies, the preferred interaural phase difference (IPD) of these neurons typically corresponds to azimuthal locations contralateral to the recorded hemisphere. Whereas binaural beats evoke only transient discharges in anesthetized cortex, neurons in awake cortex respond throughout the IPD cycle. In this regard, responses are consistent with observations at earlier stations of the auditory pathway. Discharge rate is a band-pass function of the frequency of IPD modulation in most neurons (73%), but both discharge rate and temporal synchrony are independent of the direction of phase modulation. When subjected to a receiver operator characteristic analysis, the responses of individual neurons are insufficient to account for the perceptual acuity of these macaques in an IPD discrimination task, suggesting the need for neural pooling at the cortical level.

Alterations of the amplitude of low-frequency fluctuation in healthy subjects with theta-burst stimulation of the cortex of the suprahyoid muscles.

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Ruan, Xiuhang; Xu, Guangqing; Gao, Cuihua; Liu, Lingling; Liu, Yanli; Jiang, Lisheng; Chen, Xin; Yu, Shaode; Jiang, Xinqing; Lan, Yue; Wei, Xinhua

2017-12-04

Theta burst stimulation (TBS) has emerged as a promising tool for the treatment of swallowing disorders; however, the short-term after-effects of brain activation induced by TBS remain unknown. Here, we measured the changes in spontaneous brain activation using the amplitude of low-frequency fluctuation (ALFF) approach in subjects who underwent different TBS protocols. Sixty right-handed healthy participants (male, n=30; female, n=30; mean age=23.5y) were recruited in this study and randomly assigned to three groups that underwent three different TBS protocols. In group 1, continuous TBS (cTBS) was positioned on the left hemisphere of the suprahyoid muscle cortex. For group 2, intermittent TBS (iTBS) was placed on the left hemisphere of the suprahyoid muscle cortex. Group 3 underwent combined cTBS/iTBS protocols in which iTBS on the right hemisphere was performed immediately after completing cTBS on the left suprahyoid muscle cortex. Compared to pre-TBS, post-cTBS showed decreased ALFF in the anterior cingulate gyrus (BA 32); post-iTBS induced an increase in ALFF in the bilateral precuneus (BA 7); and post-cTBS/iTBS induced a decrease in ALFF in the brainstem, and resulted in increased ALFF in the middle cingulate gyrus (BA 24) as well as the left precentral gyrus (BA 6). Compared the effect of post-TBS protocols, increased ALFF was found in left posterior cerebellum lobe and left inferior parietal lobule (BA 40) (post-cTBS vs post-iTBS), and decreased ALFF exhibited in paracentral lobule (BA 4) (post-iTBS vs post-cTBS/iTBS). These findings indicate that multiple brain areas involved in swallowing regulation after stimulation of TBS over the suprahyoid muscles. cTBS induces decreased after-effects while iTBS results in increased after-effects on spontaneous brain activation. Moreover, iTBS can eliminate the after-effects of cTBS applied on the contralateral swallowing cortex and alter the activity of contralateral motor cortex and brainstem. Our findings provide a

Incidence of contralateral versus ipsilateral neurological signs associated with lateralised Hansen type I disc extrusion

International Nuclear Information System (INIS)

Smith, J.D.; Newell, S.M.; Budsberg, S.C.; Bennett, R.A.

1997-01-01

Asymmetrical neurological signs were noted in 50 dogs presenting with Hansen type I thoracolumbar disc extrusion. Thoracolumbar myelograms and surgical decompression were performed in all cases. Dogs were divided into two groups (acute and chronic) based on the duration of clinical signs prior to presentation to the University of Georgia. Lateralising extradural cord compressive lesions were noted on all myelograms. In the acute group, 35 per cent of the dogs had asymmetrical neurological signs contralateral to the myelographic and surgical lesion, while in the chronic group only 11 per cent had neurological signs contralateral to the lesion. There was found to be no significant difference in frequency of contralateral asymmetrical clinical signs between the two groups (Fischer's exact test; P = 0.095). The high frequency of contralateral signs documents the importance of thoracolumbar myelography for accurate localisation of the disc material before decompressive surgery

Contralateral Deep Vein Thrombosis after Iliac Vein Stent Placement in Patients with May-Thurner Syndrome.

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Le, Trong Binh; Lee, Taeg Ki; Park, Keun-Myoung; Jeon, Yong Sun; Hong, Kee Chun; Cho, Soon Gu

2018-04-25

To investigate the incidence and potential causes of contralateral deep vein thrombosis (DVT) after common iliac vein (CIV) stent placement in patients with May-Thurner syndrome (MTS). Data of 111 patients (women: 73%) who had CIV stent implantation for symptomatic MTS at a single center were retrospectively analyzed. Mean patient age was 63.1 ± 15.2 years. Median follow-up was 36 months (range, 1-142 months). Stent location was determined by venogram and classified as extended to the inferior vena cava (IVC), covered the confluence, or confined to the iliac vein. Potential causes of contralateral DVT were presumed based on venographic findings. The relationship between stent location and contralateral DVT was analyzed. Ten patients (9%, men/women: 4/6) exhibited contralateral DVT at a median timing of 40 months (range, 6-98 months). Median age was 69 years (range, 42-85 years). Median follow-up was 73.5 months (range, 20-134 months). Potential causes were venous intimal hyperplasia (VIH) (n = 7), "jailing" (n = 2), and indeterminate (n = 1). All patients with VIH had previous CIV stents overextended to the IVC. Overextension of CIV stent was associated with contralateral DVT (P VIH should be considered a potential cause. Copyright © 2018 SIR. Published by Elsevier Inc. All rights reserved.

Contralateral prophylactic mastectomy: current perspectives

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Yao, Katharine; Sisco, Mark; Bedrosian, Isabelle

2016-01-01

There has been an increasing trend in the use of contralateral prophylactic mastectomy (CPM) in the United States among women diagnosed with unilateral breast cancer, particularly young women. Approximately one-third of women CPM in the US. Most studies have shown that the CPM trend is mainly patient-driven, which reflects a changing environment for newly diagnosed breast cancer patients. The most common reason that women choose CPM is based on misperceptions about CPM’s effect on survival and overestimation of their contralateral breast cancer (CBC) risk. No prospective studies have shown survival benefit to CPM, and the CBC rate for most women is low at 10 years. Fear of recurrence is also a big driver of CPM decisions. Nonetheless, studies have shown that women are mostly satisfied with undergoing CPM, but complications and subsequent surgeries with reconstruction have been associated with dissatisfaction with CPM. Studies on surgeon’s perspectives on CPM are sparse but show that the most common reasons surgeons discuss CPM with patients is because of a suspicious family history or for a patient who is a confirmed BRCA mutation carrier. Studies on the cost–effectiveness of CPM have been conflicting and are highly dependent on patient’s quality of life after CPM. Most recent guidelines for CPM are contradictory. Future areas of research include the development of interventions to better inform patients about CPM, modification of the guidelines to form a more consistent statement, longer term studies on CBC risk and CPM’s effect on survival, and prospective studies that track the psychosocial effects of CPM on body image and sexuality. PMID:27382334

Predicting perceptual learning from higher-order cortical processing.

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Wang, Fang; Huang, Jing; Lv, Yaping; Ma, Xiaoli; Yang, Bin; Wang, Encong; Du, Boqi; Li, Wu; Song, Yan

2016-01-01

Visual perceptual learning has been shown to be highly specific to the retinotopic location and attributes of the trained stimulus. Recent psychophysical studies suggest that these specificities, which have been associated with early retinotopic visual cortex, may in fact not be inherent in perceptual learning and could be related to higher-order brain functions. Here we provide direct electrophysiological evidence in support of this proposition. In a series of event-related potential (ERP) experiments, we recorded high-density electroencephalography (EEG) from human adults over the course of learning in a texture discrimination task (TDT). The results consistently showed that the earliest C1 component (68-84ms), known to reflect V1 activity driven by feedforward inputs, was not modulated by learning regardless of whether the behavioral improvement is location specific or not. In contrast, two later posterior ERP components (posterior P1 and P160-350) over the occipital cortex and one anterior ERP component (anterior P160-350) over the prefrontal cortex were progressively modified day by day. Moreover, the change of the anterior component was closely correlated with improved behavioral performance on a daily basis. Consistent with recent psychophysical and imaging observations, our results indicate that perceptual learning can mainly involve changes in higher-level visual cortex as well as in the neural networks responsible for cognitive functions such as attention and decision making. Copyright © 2015 Elsevier Inc. All rights reserved.

Early Contralateral Shoulder-Arm Morbidity in Breast Cancer Patients Enrolled in a Randomized Trial of Post-Surgery Radiation Therapy

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Nele Adriaenssens

2012-01-01

Full Text Available Introduction Shoulder/arm morbidity is a common complication of breast cancer surgery and radiotherapy (RT, but little is known about acute contralateral morbidity. Methods Patients were 118 women enrolled in a RT trial. Arm volume and shoulder mobility were assessed before and 1–3 months after RT. Correlations and linear regression were used to analyze changes affecting ipsilateral and contralateral arms, and changes affecting relative interlimb differences (RID. Results Changes affecting one limb correlated with changes affecting the other limb. Arm volume between the two limbs correlated (R = 0.57. Risk factors were weight increase and axillary dissection. Contralateral and ipsilateral loss of abduction strongly correlated (R = 0.78. Changes of combined RID exceeding 10% affected the ipsilateral limb in 25% of patients, and the contralateral limb in 18%. Aromatase inhibitor therapy was significantly associated with contralateral loss of abduction. Conclusions High incidence of early contralateral arm morbidity warrants further investigations.

A case of loss of consciousness with contralateral acute subdural haematoma during awake craniotomy

OpenAIRE

Kamata, Kotoe; Maruyama, Takashi; Nitta, Masayuki; Ozaki, Makoto; Muragaki, Yoshihiro; Okada, Yoshikazu

2014-01-01

We are reporting the case of a 56-year-old woman who developed loss of consciousness during awake craniotomy. A thin subdural haematoma in the contralateral side of the craniotomy was identified with intraoperative magnetic resonance imaging and subsequently removed. Our case indicates that contralateral acute subdural haematoma could be a cause of deterioration of the conscious level during awake craniotomy.

A case of loss of consciousness with contralateral acute subdural haematoma during awake craniotomy

Science.gov (United States)

Kamata, Kotoe; Maruyama, Takashi; Nitta, Masayuki; Ozaki, Makoto; Muragaki, Yoshihiro; Okada, Yoshikazu

2014-01-01

We are reporting the case of a 56-year-old woman who developed loss of consciousness during awake craniotomy. A thin subdural haematoma in the contralateral side of the craniotomy was identified with intraoperative magnetic resonance imaging and subsequently removed. Our case indicates that contralateral acute subdural haematoma could be a cause of deterioration of the conscious level during awake craniotomy. PMID:25301378

Unilateral hypoplasia with contralateral hypertrophy of anterior belly of digastric muscle: a case report.

Science.gov (United States)

Ochoa-Escudero, Martin; Juliano, Amy F

2016-10-01

Anomalies of the anterior belly of the digastric muscle (DM) are uncommon. We present a case of hypoplasia of the anterior belly of the left DM with hypertrophy of the anterior belly of the contralateral DM. The importance of recognizing this finding is to differentiate hypoplasia of the anterior belly of the DM from denervation atrophy, and not to confuse contralateral hypertrophy with a submental mass or lymphadenopathy. In denervation atrophy of the anterior belly of the DM, associated atrophy of the ipsilateral mylohyoid muscle is present. Hypertrophy of the anterior belly of the contralateral DM can be differentiated from a submental mass or lymphadenopathy by recognizing its isodensity on computed tomography and isointensity on magnetic resonance imaging to other muscles, without abnormal contrast enhancement.

Impact of contra-lateral breast reshaping on mammographic surveillance in women undergoing breast reconstruction following mastectomy for breast cancer.

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Nava, Maurizio B; Rocco, Nicola; Catanuto, Giuseppe; Falco, Giuseppe; Capalbo, Emanuela; Marano, Luigi; Bordoni, Daniele; Spano, Andrea; Scaperrotta, Gianfranco

2015-08-01

The ultimate goal of breast reconstruction is to achieve symmetry with the contra-lateral breast. Contra-lateral procedures with wide parenchymal rearrangements are suspected to impair mammographic surveillance. This study aims to evaluate the impact on mammographic detection of mastopexies and breast reductions for contralateral adjustment in breast reconstruction. We retrospectively evaluated 105 women affected by uni-lateral breast cancer who underwent mastectomy and immediate two-stage reconstruction between 2002 and 2007. We considered three groups according to the contra-lateral reshaping technique: mastopexy or breast reduction with inferior dermoglandular flap (group 1); mastopexy or breast reduction without inferior dermoglandular flap (group 2); no contra-lateral reshaping (group 3). We assessed qualitative mammographic variations and breast density in the three groups. Statistically significant differences have been found when comparing reshaped groups with non reshaped groups regarding parenchymal distortions, skin thickening and stromal edema, but these differences did not affect cancer surveillance. The surveillance mammography diagnostic accuracy in contra-lateral cancer detection was not significantly different between the three groups (p = 0.56), such as the need for MRI for equivocal findings at mammographic contra-lateral breast (p = 0.77) and the need for core-biopsies to confirm mammographic suspect of contra-lateral breast cancer (p = 0.90). This study confirms previous reports regarding the safety of mastopexies and breast reductions when performed in the setting of contra-lateral breast reshaping after breast reconstruction. Mammographic accuracy, sensitivity and specificity are not affected by the glandular re-arrangement. These results provide a further validation of the safety of current reconstructive paradigms. Copyright © 2015 Elsevier Ltd. All rights reserved.

Contralateral cortico-ponto-cerebellar pathways reconstruction in humans in vivo: implications for reciprocal cerebro-cerebellar structural connectivity in motor and non-motor areas.

Science.gov (United States)

Palesi, Fulvia; De Rinaldis, Andrea; Castellazzi, Gloria; Calamante, Fernando; Muhlert, Nils; Chard, Declan; Tournier, J Donald; Magenes, Giovanni; D'Angelo, Egidio; Gandini Wheeler-Kingshott, Claudia A M

2017-10-09

Cerebellar involvement in cognition, as well as in sensorimotor control, is increasingly recognized and is thought to depend on connections with the cerebral cortex. Anatomical investigations in animals and post-mortem humans have established that cerebro-cerebellar connections are contralateral to each other and include the cerebello-thalamo-cortical (CTC) and cortico-ponto-cerebellar (CPC) pathways. CTC and CPC characterization in humans in vivo is still challenging. Here advanced tractography was combined with quantitative indices to compare CPC to CTC pathways in healthy subjects. Differently to previous studies, our findings reveal that cerebellar cognitive areas are reached by the largest proportion of the reconstructed CPC, supporting the hypothesis that a CTC-CPC loop provides a substrate for cerebro-cerebellar communication during cognitive processing. Amongst the cerebral areas identified using in vivo tractography, in addition to the cerebral motor cortex, major portions of CPC streamlines leave the prefrontal and temporal cortices. These findings are useful since provide MRI-based indications of possible subtending connectivity and, if confirmed, they are going to be a milestone for instructing computational models of brain function. These results, together with further multi-modal investigations, are warranted to provide important cues on how the cerebro-cerebellar loops operate and on how pathologies involving cerebro-cerebellar connectivity are generated.

The Effect of Learning Disability on Contralateral Suppression of Otoacoustic Emissions in Primary Students

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Saeid Sarough Farahani

2006-06-01

Full Text Available Background and Aim: One of the most significant complaints of children with learning disability (LD is difficulty in understanding speech in the presence of background noise. Different studies have shown that the medial olivocochlear bundle(MOCB may play a role in hearing in noise. The MOCB function can be evaluated by the contralateral suppression of tone burst evoked otoacoustic emissions (TBEOAEs.The aim of the present study was to evaluate frequency specifications of MOCB by the contralateral suppression of TBEOAEs at 1,2,3 and 4 KHz in response to contralateral white noise in LD students. Materials and Methods: This case-control study was conducted on 34 LD students aged 7-11 years and 31 normal students matched for age.The contralateral suppression of TBEOAEs was evaluated by comparing TBEOAEs amplitudes with and without contralateral white noise. Results: In the absence of noise there was no significant difference between TBEOAEs amplitudes of two groups. In the presence of noise significant decrease was seen in TBEOAEs amplitudes at 1,2,3 and 4 KHz in both groups. In LD students the amount of this decrement at 1,2 and 4 KHz was lower than in the normal students. Conclusion: A significant diminished suppression effect at 1,2 and 4 KHz in LD students indicates that at these frequency regions MOCB function was reduced. Therefore it suggests that the assessment of MOCB by evaluating the suppression effect of TBEOAEs included in the test battery approach used in the diagnostic of LD students.

Orofacial Neuropathic Pain Leads to a Hyporesponsive Barrel Cortex with Enhanced Structural Synaptic Plasticity.

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Thibault, Karine; Rivière, Sébastien; Lenkei, Zsolt; Férézou, Isabelle; Pezet, Sophie

2016-01-01

Chronic pain is a long-lasting debilitating condition that is particularly difficult to treat due to the lack of identified underlying mechanisms. Although several key contributing processes have been described at the level of the spinal cord, very few studies have investigated the supraspinal mechanisms underlying chronic pain. Using a combination of approaches (cortical intrinsic imaging, immunohistochemical and behavioural analysis), our study aimed to decipher the nature of functional and structural changes in a mouse model of orofacial neuropathic pain, focusing on cortical areas involved in various pain components. Our results show that chronic neuropathic orofacial pain is associated with decreased haemodynamic responsiveness to whisker stimulation in the barrel field cortex. This reduced functional activation is likely due to the increased basal neuronal activity (measured indirectly using cFos and phospho-ERK immunoreactivity) observed in several cortical areas, including the contralateral barrel field, motor and cingulate cortices. In the same animals, immunohistochemical analysis of markers for active pre- or postsynaptic elements (Piccolo and phospho-Cofilin, respectively) revealed an increased immunofluorescence in deep cortical layers of the contralateral barrel field, motor and cingulate cortices. These results suggest that long-lasting orofacial neuropathic pain is associated with exacerbated neuronal activity and synaptic plasticity at the cortical level.

Kombination von Platte und Fixateur externe zur biologischen Osteosynthese von Mehrfragmentfrakturen

NARCIS (Netherlands)

Pippow, A.; Krähenbühl, L.; Michel, M. C.; Witschger, P.

2002-01-01

In a comminuted fracture, a unilateral plate doesn't always give enough stability because the contralateral cortex cannot be used as a buttress. New plate systems as the Locking Compression Plate (LCP) may solve this problem. Another method to stabilize the contralateral cortex is by using an

Comparison of visual receptive fields in the dorsolateral prefrontal cortex and ventral intraparietal area in macaques.

Science.gov (United States)

Viswanathan, Pooja; Nieder, Andreas

2017-12-01

The concept of receptive field (RF) describes the responsiveness of neurons to sensory space. Neurons in the primate association cortices have long been known to be spatially selective but a detailed characterisation and direct comparison of RFs between frontal and parietal association cortices are missing. We sampled the RFs of a large number of neurons from two interconnected areas of the frontal and parietal lobes, the dorsolateral prefrontal cortex (dlPFC) and ventral intraparietal area (VIP), of rhesus monkeys by systematically presenting a moving bar during passive fixation. We found that more than half of neurons in both areas showed spatial selectivity. Single neurons in both areas could be assigned to five classes according to the spatial response patterns: few non-uniform RFs with multiple discrete response maxima could be dissociated from the vast majority of uniform RFs showing a single maximum; the latter were further classified into full-field and confined foveal, contralateral and ipsilateral RFs. Neurons in dlPFC showed a preference for the contralateral visual space and collectively encoded the contralateral visual hemi-field. In contrast, VIP neurons preferred central locations, predominantly covering the foveal visual space. Putative pyramidal cells with broad-spiking waveforms in PFC had smaller RFs than putative interneurons showing narrow-spiking waveforms, but distributed similarly across the visual field. In VIP, however, both putative pyramidal cells and interneurons had similar RFs at similar eccentricities. We provide a first, thorough characterisation of visual RFs in two reciprocally connected areas of a fronto-parietal cortical network. © 2017 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Can sparing of the superficial contralateral parotid lobe reduce xerostomia following radiotherapy for head and neck cancer?

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Nevens, Daan; Nuyts, Sandra

2017-12-01

The purpose of this study is to see whether sparing the superficial contralateral parotid lobe can help limiting xerostomia following radiotherapy for head and neck cancer. 88 patients that were included in two prospective randomized studies were analysed in the current study. Using the dosimetry of both the parotid glands, we divided our patients in four groups. Group 1 includes patients where we were able to reduce the radiation dose below the threshold in order to spare both the ipsilateral and contralateral parotid glands, Group 2 consists of patients where only the contralateral parotid gland could be spared. Group 3 consists of patients where only the contralateral superficial parotid lobe could be spared, while in Group 4 not even the contralateral superficial lobe could be spared. When we compared Group 1 and Group 2, we did not observe a significant difference between both groups in terms of xerostomia scores at 6 or 12 months. When we compared these groups with Group 3, we observed significant differences with more xerostomia in Group 3 where only the contralateral superficial lobe was spared. A significant difference was also observed between Group 3 and Group 4 with more xerostomia in Group 4. Sparing of just one superficial parotid lobe results in less xerostomia when compared to not sparing any lobe of both parotid glands. Advances in knowledge: When sparing of the whole contralateral parotid gland is not possible, delineating both the superficial parotid glands and trying to spare at least one of them can mean a way forward in limiting xerostomia in head and neck cancer patients treated with radiotherapy.

Antinociception induced by epidural motor cortex stimulation in naive conscious rats is mediated by the opioid system.

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Fonoff, Erich Talamoni; Dale, Camila Squarzoni; Pagano, Rosana Lima; Paccola, Carina Cicconi; Ballester, Gerson; Teixeira, Manoel Jacobsen; Giorgi, Renata

2009-01-03

Epidural motor cortex stimulation (MCS) has been used for treating patients with neuropathic pain resistant to other therapeutic approaches. Experimental evidence suggests that the motor cortex is also involved in the modulation of normal nociceptive response, but the underlying mechanisms of pain control have not been clarified yet. The aim of this study was to investigate the effects of epidural electrical MCS on the nociceptive threshold of naive rats. Electrodes were placed on epidural motor cortex, over the hind paw area, according to the functional mapping accomplished in this study. Nociceptive threshold and general activity were evaluated under 15-min electrical stimulating sessions. When rats were evaluated by the paw pressure test, MCS induced selective antinociception in the paw contralateral to the stimulated cortex, but no changes were noticed in the ipsilateral paw. When the nociceptive test was repeated 15 min after cessation of electrical stimulation, the nociceptive threshold returned to basal levels. On the other hand, no changes in the nociceptive threshold were observed in rats evaluated by the tail-flick test. Additionally, no behavioral or motor impairment were noticed in the course of stimulation session at the open-field test. Stimulation of posterior parietal or somatosensory cortices did not elicit any changes in the general activity or nociceptive response. Opioid receptors blockade by naloxone abolished the increase in nociceptive threshold induced by MCS. Data shown herein demonstrate that epidural electrical MCS elicits a substantial and selective antinociceptive effect, which is mediated by opioids.

Metachronous contralateral breast cancer as first event of relapse

International Nuclear Information System (INIS)

La Rochefordiere, Anne de; Mouret-Fourme, Emmanuelle; Asselain, Bernard; Scholl, Susan M.; Campana, Francois; Broeet, Philippe; Fourquet, Alain

1996-01-01

Purpose: To determine which clinical, biological, or treatment-related factors of the first and second primary breast cancers influenced the outcome following contralateral breast carcinoma (CBC). Methods and Materials: By August 1994, 319 of 6406 patients with clinical Stage 0 to III breast carcinoma treated between 1981 and 1987 at Institut Curie had developed a second breast cancer that was diagnosed more than 6 months following ipsilateral breast cancer. Of these 319 patients, 235 had a CBC as the first recurrent event and constitute the study population. Comparisons of first and second breast tumor characteristics were done using Fisher's exact test. Survival distributions from the date of CBC were compared by the log-rank test. Prognostic factors for local relapses, distant relapses, and survival after CBC were assessed by univariate and multivariate analysis using the Cox proportional hazards model. Results: The diagnosis of CBC was more frequently guided by mammographies than for ipsilateral tumors (p 5 years) had no influence on survival. Cox model analysis showed that the risk factors for distant metastases were stage and progesterone receptor levels of the contralateral tumor. The risk of distant failure in CBC was not influenced by the extent of surgery. Conclusions: In this selected population of CBCs as first recurrent events, a follow-up policy based on clinical examination and annual mammography enabled the detection of CBCs at an earlier stage than the primary ipsilateral cancer. The outcome after CBC was determined only by the characteristics of the contralateral tumor. Breast-conserving treatment should be recommended when it is feasible. Adjuvant chemotherapy should be delivered according to the same criteria as the primary tumor

Resolving the organization of the third tier visual cortex in primates: a hypothesis-based approach.

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Angelucci, Alessandra; Rosa, Marcello G P

2015-01-01

As highlighted by several contributions to this special issue, there is still ongoing debate about the number, exact location, and boundaries of the visual areas located in cortex immediately rostral to the second visual area (V2), i.e., the "third tier" visual cortex, in primates. In this review, we provide a historical overview of the main ideas that have led to four models of third tier cortex organization, which are at the center of today's debate. We formulate specific predictions of these models, and compare these predictions with experimental evidence obtained primarily in New World primates. From this analysis, we conclude that only one of these models (the "multiple-areas" model) can accommodate the breadth of available experimental evidence. According to this model, most of the third tier cortex in New World primates is occupied by two distinct areas, both representing the full contralateral visual quadrant: the dorsomedial area (DM), restricted to the dorsal half of the third visual complex, and the ventrolateral posterior area (VLP), occupying its ventral half and a substantial fraction of its dorsal half. DM belongs to the dorsal stream of visual processing, and overlaps with macaque parietooccipital (PO) area (or V6), whereas VLP belongs to the ventral stream and overlaps considerably with area V3 proposed by others. In contrast, there is substantial evidence that is inconsistent with the concept of a single elongated area V3 lining much of V2. We also review the experimental evidence from macaque monkey and humans, and propose that, once the data are interpreted within an evolutionary-developmental context, these species share a homologous (but not necessarily identical) organization of the third tier cortex as that observed in New World monkeys. Finally, we identify outstanding issues, and propose experiments to resolve them, highlighting in particular the need for more extensive, hypothesis-driven investigations in macaque and humans.

Mild Contralesional Hypothermia Reduces Use of the Unimpaired Forelimb in a Skilled Reaching Task After Motor Cortex Injury in Rats.

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Klahr, Ana C; Fagan, Kelly; Aziz, Jasmine R; John, Roseleen; Colbourne, Frederick

2018-06-01

Therapeutic hypothermia (TH) mitigates neuronal injury in models of ischemic stroke. Although this therapy is meant for injured tissue, most protocols cool the whole body, including the contralesional hemisphere. Neuroplasticity responses within this hemisphere can affect functional outcome. Thus, cooling the contralesional hemisphere serves no clear neuroprotective function and may instead be detrimental. In this study, we cooled the contralesional hemisphere to determine whether this harms behavioral recovery after cortical injury in rats. All rats were trained on skilled reaching and walking tasks. Rats then received a motor cortex insult contralateral to their dominant paw after which they were randomly assigned to focal contralesional TH (∼33°C) for 1-48, 1-97, or 48-96 hours postinjury, or to a normothermic control group. Contralesional cooling did not impact lesion volume (p = 0.371) and had minimal impact on neurological outcome of the impaired limb. However, rats cooled early were significantly less likely to shift paw preference to the unimpaired paw (p ≤ 0.043), suggesting that cooling reduced learned nonuse. In a second experiment, we tested whether cooling impaired learning of the skilled reaching task in naive rats. Localized TH applied to the hemisphere contralateral or ipsilateral to the preferred paw did not impair learning (p ≥ 0.677) or dendritic branching/length in the motor cortex (p ≥ 0.105). In conclusion, localized TH did not impair learning or plasticity in the absence of neural injury, but contralesional TH may reduce unwanted shifts in limb preference after stroke.

Stronger efferent suppression of cochlear neural potentials by contralateral acoustic stimulation in awake than in anesthetized chinchilla

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Cristian eAedo

2015-03-01

Full Text Available There are two types of sensory cells in the mammalian cochlea, inner hair cells, which make synaptic contact with auditory-nerve afferent fibers, and outer hair cells that are innervated by crossed and uncrossed medial olivocochlear (MOC efferent fibers. Contralateral acoustic stimulation activates the uncrossed efferent MOC fibers reducing cochlear neural responses, thus modifying the input to the central auditory system. The chinchilla, among all studied mammals, displays the lowest percentage of uncrossed MOC fibers raising questions about the strength and frequency distribution of the contralateral-sound effect in this species. On the other hand, MOC effects on cochlear sensitivity have been mainly studied in anesthetized animals and since the MOC-neuron activity depends on the level of anesthesia, it is important to assess the influence of anesthesia in the strength of efferent effects. Seven adult chinchillas (Chinchilla laniger were chronically implanted with round-window electrodes in both cochleae. We compared the effect of contralateral sound in awake and anesthetized condition. Compound action potentials (CAP and cochlear microphonics (CM were measured in the ipsilateral cochlea in response to tones in absence and presence of contralateral sound. Control measurements performed after middle-ear muscles section in one animal discarded any possible middle-ear reflex activation. Contralateral sound produced CAP amplitude reductions in all chinchillas, with suppression effects greater by about 1-3 dB in awake than in anesthetized animals. In contrast, CM amplitude increases of up to 1.9 dB were found in only three awake chinchillas. In both conditions the strongest efferent effects were produced by contralateral tones at frequencies equal or close to those of ipsilateral tones. Contralateral CAP suppressions for 1-6 kHz ipsilateral tones corresponded to a span of uncrossed MOC fiber innervation reaching at least the central third of the

Stronger efferent suppression of cochlear neural potentials by contralateral acoustic stimulation in awake than in anesthetized chinchilla.

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Aedo, Cristian; Tapia, Eduardo; Pavez, Elizabeth; Elgueda, Diego; Delano, Paul H; Robles, Luis

2015-01-01

There are two types of sensory cells in the mammalian cochlea, inner hair cells, which make synaptic contact with auditory-nerve afferent fibers, and outer hair cells that are innervated by crossed and uncrossed medial olivocochlear (MOC) efferent fibers. Contralateral acoustic stimulation activates the uncrossed efferent MOC fibers reducing cochlear neural responses, thus modifying the input to the central auditory system. The chinchilla, among all studied mammals, displays the lowest percentage of uncrossed MOC fibers raising questions about the strength and frequency distribution of the contralateral-sound effect in this species. On the other hand, MOC effects on cochlear sensitivity have been mainly studied in anesthetized animals and since the MOC-neuron activity depends on the level of anesthesia, it is important to assess the influence of anesthesia in the strength of efferent effects. Seven adult chinchillas (Chinchilla laniger) were chronically implanted with round-window electrodes in both cochleae. We compared the effect of contralateral sound in awake and anesthetized condition. Compound action potentials (CAP) and cochlear microphonics (CM) were measured in the ipsilateral cochlea in response to tones in absence and presence of contralateral sound. Control measurements performed after middle-ear muscles section in one animal discarded any possible middle-ear reflex activation. Contralateral sound produced CAP amplitude reductions in all chinchillas, with suppression effects greater by about 1-3 dB in awake than in anesthetized animals. In contrast, CM amplitude increases of up to 1.9 dB were found in only three awake chinchillas. In both conditions the strongest efferent effects were produced by contralateral tones at frequencies equal or close to those of ipsilateral tones. Contralateral CAP suppressions for 1-6 kHz ipsilateral tones corresponded to a span of uncrossed MOC fiber innervation reaching at least the central third of the chinchilla cochlea.

Screening for carcinoma in situ in the contralateral testicle in patients with testicular cancer

DEFF Research Database (Denmark)

Kier, M G G; Lauritsen, Jakob; Almstrup, Kristian

2015-01-01

population-based screening programme for contralateral CIS in patients with testicular cancer showed no significant difference in the risk for metachronous GCC between a screened and an unscreened cohort. Single-site biopsy including modern immunohistochemistry does not identify all cases of CIS.......BACKGROUND: Screening programmes for contralateral carcinoma in situ (CIS) testis in patients with unilateral germ-cell cancer (GCC) have never been evaluated. We investigated the effect of screening for contralateral CIS in a large nation-wide, population-based study. PATIENTS AND METHODS...... years was 1.9% in the screened cohort and 3.1% in the unscreened cohort (P = 0.097), hazard ratio (HR) for the unscreened cohort: 1.59 (P = 0.144). Expert revision with contemporary methodology of CIS-negative biopsy samples from patients with metachronous cancer revealed CIS in 17 out of 45 (38%) cases...

Modulating phonemic fluency performance in healthy subjects with transcranial magnetic stimulation over the left or right lateral frontal cortex.

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Smirni, Daniela; Turriziani, Patrizia; Mangano, Giuseppa Renata; Bracco, Martina; Oliveri, Massimiliano; Cipolotti, Lisa

2017-07-28

A growing body of evidence have suggested that non-invasive brain stimulation techniques, such as transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS), can improve the performance of aphasic patients in language tasks. For example, application of inhibitory rTMS or tDCs over the right frontal lobe of dysphasic patients resulted in improved naming abilities. Several studies have also reported that in healthy controls (HC) tDCS application over the left prefrontal cortex (PFC) improve performance in naming and semantic fluency tasks. The aim of this study was to investigate in HC, for the first time, the effects of inhibitory repetitive TMS (rTMS) over left and right lateral frontal cortex (BA 47) on two phonemic fluency tasks (FAS or FPL). 44 right-handed HCs were administered rTMS or sham over the left or right lateral frontal cortex in two separate testing sessions, with a 24h interval, followed by the two phonemic fluency tasks. To account for possible practice effects, an additional 22 HCs were tested on only the phonemic fluency task across two sessions with no stimulation. We found that rTMS-inhibition over the left lateral frontal cortex significantly worsened phonemic fluency performance when compared to sham. In contrast, rTMS-inhibition over the right lateral frontal cortex significantly improved phonemic fluency performance when compared to sham. These results were not accounted for practice effects. We speculated that rTMS over the right lateral frontal cortex may induce plastic neural changes to the left lateral frontal cortex by suppressing interhemispheric inhibitory interactions. This resulted in an increased excitability (disinhibition) of the contralateral unstimulated left lateral frontal cortex, consequently enhancing phonemic fluency performance. Conversely, application of rTMS over the left lateral frontal cortex may induce a temporary, virtual lesion, with effects similar to those reported in left frontal

Top-down modulation from inferior frontal junction to FEFs and intraparietal sulcus during short-term memory for visual features.

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Sneve, Markus H; Magnussen, Svein; Alnæs, Dag; Endestad, Tor; D'Esposito, Mark

2013-11-01

Visual STM of simple features is achieved through interactions between retinotopic visual cortex and a set of frontal and parietal regions. In the present fMRI study, we investigated effective connectivity between central nodes in this network during the different task epochs of a modified delayed orientation discrimination task. Our univariate analyses demonstrate that the inferior frontal junction (IFJ) is preferentially involved in memory encoding, whereas activity in the putative FEFs and anterior intraparietal sulcus (aIPS) remains elevated throughout periods of memory maintenance. We have earlier reported, using the same task, that areas in visual cortex sustain information about task-relevant stimulus properties during delay intervals [Sneve, M. H., Alnæs, D., Endestad, T., Greenlee, M. W., & Magnussen, S. Visual short-term memory: Activity supporting encoding and maintenance in retinotopic visual cortex. Neuroimage, 63, 166-178, 2012]. To elucidate the temporal dynamics of the IFJ-FEF-aIPS-visual cortex network during memory operations, we estimated Granger causality effects between these regions with fMRI data representing memory encoding/maintenance as well as during memory retrieval. We also investigated a set of control conditions involving active processing of stimuli not associated with a memory task and passive viewing. In line with the developing understanding of IFJ as a region critical for control processes with a possible initiating role in visual STM operations, we observed influence from IFJ to FEF and aIPS during memory encoding. Furthermore, FEF predicted activity in a set of higher-order visual areas during memory retrieval, a finding consistent with its suggested role in top-down biasing of sensory cortex.

Equine ulnar fracture repair with locking compression plates can be associated with inadvertent penetration of the lateral cortex of the radius.

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Kuemmerle, Jan M; Kühn, Karolin; Bryner, Marco; Fürst, Anton E

2013-10-01

To evaluate if the use of locking head screws (LHS) in the distal holes of a locking compression plate (LCP) applied to the caudal aspect of the ulna to treat equine ulnar fractures is associated with a risk of injury to the lateral cortex of the radius. Controlled laboratory study. Cadaveric equine forelimbs (n = 8 pair). After transverse ulnar osteotomy, osteosynthesis was performed with a narrow 10-13 hole 4.5/5.0 LCP applied to the caudal aspect of each ulna. The distal 3 holes were filled with 4.5 mm cortex screws (CS) in 1 limb (group 1) and with 5.0 mm LHS contralaterally (group 2). CS were inserted in an angle deemed appropriate by the surgeon and LHS were inserted perpendicular to the plate. Implant position and injury to the lateral cortex of the radius were assessed by radiography, CT, and limb dissection. In group 1, injury of the lateral radius cortex did not occur. In group 2, 4 limbs and 6/24 LHS were associated with injury of the lateral radius cortex by penetration of a LHS. This difference was statistically significant. CS were inserted with a mean angle of 17.6° from the sagittal plane in a caudolateral-craniomedial direction. Use of LHS in the distal part of a LCP applied to the caudal aspect of the ulna is associated with a risk of inadvertent injury to the lateral cortex of the radius. © Copyright 2013 by The American College of Veterinary Surgeons.

Electrical stimulation of motor cortex in the uninjured hemisphere after chronic unilateral injury promotes recovery of skilled locomotion through ipsilateral control.

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Carmel, Jason B; Kimura, Hiroki; Martin, John H

2014-01-08

Partial injury to the corticospinal tract (CST) causes sprouting of intact axons at their targets, and this sprouting correlates with functional improvement. Electrical stimulation of motor cortex augments sprouting of intact CST axons and promotes functional recovery when applied soon after injury. We hypothesized that electrical stimulation of motor cortex in the intact hemisphere after chronic lesion of the CST in the other hemisphere would restore function through ipsilateral control. To test motor skill, rats were trained and tested to walk on a horizontal ladder with irregularly spaced rungs. Eight weeks after injury, produced by pyramidal tract transection, half of the rats received forelimb motor cortex stimulation of the intact hemisphere. Rats with injury and stimulation had significantly improved forelimb control compared with rats with injury alone and achieved a level of proficiency similar to uninjured rats. To test whether recovery of forelimb function was attributable to ipsilateral control, we selectively inactivated the stimulated motor cortex using the GABA agonist muscimol. The dose of muscimol we used produces strong contralateral but no ipsilateral impairments in naive rats. In rats with injury and stimulation, but not those with injury alone, inactivation caused worsening of forelimb function; the initial deficit was reinstated. These results demonstrate that electrical stimulation can promote recovery of motor function when applied late after injury and that motor control can be exerted from the ipsilateral motor cortex. These results suggest that the uninjured motor cortex could be targeted for brain stimulation in people with large unilateral CST lesions.

Progressive contralateral hippocampal atrophy following surgery for medically refractory temporal lobe epilepsy.

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Elliott, Cameron A; Gross, Donald W; Wheatley, B Matt; Beaulieu, Christian; Sankar, Tejas

2016-09-01

Determine the extent and time course of volumetric changes in the contralateral hippocampus following surgery for medically refractory temporal lobe epilepsy (TLE). Serial T1-weighted MRI brain scans were obtained in 26 TLE patients pre- and post-temporal lobe epilepsy surgery as well as in 12 control subjects of similar age. Patients underwent either anterior temporal lobectomy (ATL) or selective amygdalohippocampectomy (SAH). Blinded, manual hippocampal volumetry (head, body, and tail) was performed in two groups: 1) two scan group [ATL (n=6); SAH (n=10)], imaged pre-surgery and on average at 5.4 years post-surgery; and 2) longitudinal group [ATL (n=8); SAH (n=2)] imaged pre-surgery and on post-operative day 1, 2, 3, 6, 60, 120 and a delayed time point (average 2.4 years). In the two scan group, there was atrophy by 12% of the unresected contralateral hippocampus (p<0.001), with atrophy being most pronounced (27%) in the hippocampal body (p<0.001) with no significant differences seen for the hippocampal head or tail. In the longitudinal group, significant atrophy was also observed for the whole hippocampus and the body with atrophy seen as early as post-operative day #1 which progressed significantly over the first post-operative week (1.3%/day and 3.0%./day, respectively) before stabilizing over the long-term to a 13% reduction in total volume. There was no significant difference in atrophy compared by surgical approach (ATL vs. SAH; p=0.94) or side (p=0.31); however, atrophy was significantly more pronounced in patients with ongoing post-operative seizures (hippocampal body, p=0.019; whole hippocampus, p=0.048). There were no detectable post-operative neuropsychological deficits attributable to contralateral hippocampal atrophy. Significant contralateral hippocampal atrophy occurs following TLE surgery, which begins immediately and progresses over the first post-operative week. The observation that seizure free patients had significantly less atrophy of the

Sustained posterior contralateral activity indicates re-entrant target processing in visual change detection: An EEG study

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Daniel eSchneider

2014-05-01

Full Text Available The present study investigated the neural mechanisms that contribute to the detection of visual feature changes between stimulus displays by means of event-related lateralizations of the electroencephalogram (EEG. Participants were instructed to respond to a luminance change in either of two lateralized stimuli that could randomly occur alone or together with an irrelevant orientation change of the same or contralateral stimulus. Task performance based on response times and accuracy was decreased compared to the remaining stimulus conditions when relevant and irrelevant feature changes were presented contralateral to each other (lateral distractor condition. The sensory response to the feature changes was reflected in a posterior contralateral positivity at around 100ms after change presentation and a posterior contralateral negativity in the N1 time window (N1pc. N2pc reflected a subsequent attentional bias in favor of the relevant luminance change. The continuation of the sustained posterior contralateral negativity (SPCN following N2pc covaried with response times within feature change conditions and revealed a posterior topography comparable to the earlier components associated with sensory and attentional mechanisms. Therefore, this component might reflect the re-processing of information based on sustained short-term memory representations in the visual system until a stable target percept is created that can serve as the perceptual basis for response selection and the initiation of goal-directed behavior.

Testicular hypertrophy as a predictor for contralateral monorchism: Retrospective review of prospectively recorded data.

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Hodhod, A; Capolicchio, J P; Jednak, R; El-Sherbiny, M

2016-02-01

Testicular hypertrophy has previously been evaluated as a predictor of monorchism. However, its implication in clinical practice is not well evaluated. The aim of the present study was to examine its value in planning the operative time. Medical charts of prospectively recorded data of 76 consecutive patients with unilateral impalpable testis from 2011 to 2014 were reviewed at the present institute. Inclusion criteria included prepubertal patients with non-palpable testes by examination under anesthesia. Contralateral testes were prospectively measured using a Takihara orchidometer. Orchiectomy or orchiopexy was performed according to the viability of the undescended testis (UDT). Collected data included age of surgery, contralateral testicular size, surgical time and laparoscopic findings. A ROC curve was used to define the best cut-off volume of the contralateral testis that can predict ipsilateral testicular viability. The Student's t-test was used to examine if this cut-off volume would be useful in allocating the operative time. Of 76 patients, four palpable testes by examination under anesthesia were excluded. The remaining 72 patients were included in the study. Ipsilateral normal viable testes were found in 26 (36.1%) patients, while 46 (63.9%) had non-viable testes (testicular nubbins or vanishing testes) (Figure). A contralateral testicular volume > 2 ml was significantly predictive for monorchism with 71.7% sensitivity and 100% specificity (P 2 ml was 50 min, which was significantly shorter than that for UDT with a contralateral size ≤ 2 ml, which was 88 min (P value for testicular hypertrophy that predicts monorchism greatly varied. This is likely due to the different methods used for testicular measurements that make it impractical to make a direct comparison. The usefulness of predicting monorchism before surgery has not previously been used as a guide for allocating operative time in the management of a unilateral non-palpable testicle. This study

Disconnection of basolateral amygdala and insular cortex disrupts conditioned approach in Pavlovian lever autoshaping.

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Nasser, Helen M; Lafferty, Danielle S; Lesser, Ellen N; Bacharach, Sam Z; Calu, Donna J

2018-01-01

Previously established individual differences in appetitive approach and devaluation sensitivity observed in goal- and sign-trackers may be attributed to differences in the acquisition, modification, or use of associative information in basolateral amygdala (BLA) pathways. Here, we sought to determine the extent to which communication of associative information between BLA and anterior portions of insular cortex (IC) supports ongoing Pavlovian conditioned approach behaviors in sign- and goal-tracking rats, in the absence of manipulations to outcome value. We hypothesized that the BLA mediates goal-, but not sign- tracking approach through interactions with the IC, a brain region involved in supporting flexible behavior. We first trained rats in Pavlovian lever autoshaping to determine their sign- or goal-tracking tendency. During alternating test sessions, we gave unilateral intracranial injections of vehicle or a cocktail of gamma-aminobutyric acid (GABA) receptor agonists, baclofen and muscimol, unilaterally into the BLA and contralaterally or ipsilaterally into the IC prior to reinforced lever autoshaping sessions. Consistent with our hypothesis we found that contralateral inactivation of BLA and IC increased the latency to approach the food cup and decreased the number of food cup contacts in goal-trackers. While contralateral inactivation of BLA and IC did not affect the total number of lever contacts in sign-trackers, this manipulation increased the latency to approach the lever. Ipsilateral inactivation of BLA and IC did not impact approach behaviors in Pavlovian lever autoshaping. These findings, contrary to our hypothesis, suggest that communication between BLA and IC maintains a representation of initially learned appetitive associations that commonly support the initiation of Pavlovian conditioned approach behavior regardless of whether it is directed at the cue or the location of reward delivery. Copyright © 2017 Elsevier Inc. All rights reserved.

Is prophylactic fixation a cost-effective method to prevent a future contralateral fragility hip fracture?

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Faucett, Scott C; Genuario, James W; Tosteson, Anna N A; Koval, Kenneth J

2010-02-01

: A previous hip fracture more than doubles the risk of a contralateral hip fracture. Pharmacologic and environmental interventions to prevent hip fracture have documented poor compliance. The purpose of this study was to examine the cost-effectiveness of prophylactic fixation of the uninjured hip to prevent contralateral hip fracture. : A Markov state-transition model was used to evaluate the cost and quality-adjusted life-years (QALYs) for unilateral fixation of hip fracture alone (including internal fixation or arthroplasty) compared with unilateral fixation and contralateral prophylactic hip fixation performed at the time of hip fracture or unilateral fixation and bilateral hip pad protection. Prophylactic fixation involved placement of a cephalomedullary nail in the uninjured hip and was initially assumed to have a relative risk of a contralateral fracture of 1%. Health states included good health, surgery-related complications requiring a second operation (infection, osteonecrosis, nonunion, and malunion), fracture of the uninjured hip, and death. The primary outcome measure was the incremental cost-effectiveness ratio estimated as cost per QALY gained in 2006 US dollars with incremental cost-effectiveness ratios below $50,000 per QALY gained considered cost-effective. Sensitivity analyses evaluated the impact of patient age, annual mortality and complication rates, intervention effectiveness, utilities, and costs on the value of prophylactic fixation. : In the baseline analysis, in a 79-year-old woman, prophylactic fixation was not found to be cost-effective (incremental cost-effectiveness ratio = $142,795/QALY). However, prophylactic fixation was found to be a cost-effective method to prevent contralateral hip fracture in: 1) women 71 to 75 years old who had 30% greater relative risk for a contralateral fracture; and 2) women younger than age 70 years. Cost-effectiveness was greater when the additional costs of prophylaxis were less than $6000. However, for

Intra- and Interhemispheric Propagation of Electrophysiological Synchronous Activity and Its Modulation by Serotonin in the Cingulate Cortex of Juvenile Mice.

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Víctor Rovira

Full Text Available Disinhibition of the cortex (e.g., by GABA -receptor blockade generates synchronous and oscillatory electrophysiological activity that propagates along the cortex. We have studied, in brain slices of the cingulate cortex of mice (postnatal age 14-20 days, the propagation along layer 2/3 as well as the interhemispheric propagation through the corpus callosum of synchronous discharges recorded extracellularly and evoked in the presence of 10 μM bicuculline by electrical stimulation of layer 1. The latency of the responses obtained at the same distance from the stimulus electrode was longer in anterior cingulate cortex (ACC: 39.53 ± 2.83 ms, n = 7 than in retrosplenial cortex slices (RSC: 21.99 ± 2.75 ms, n = 5; p<0.05, which is equivalent to a lower propagation velocity in the dorso-ventral direction in ACC than in RSC slices (43.0 mm/s vs 72.9 mm/s. We studied the modulation of this propagation by serotonin. Serotonin significantly increased the latency of the intracortical synchronous discharges (18.9% in the ipsilateral hemisphere and 40.2% in the contralateral hemisphere, and also increased the interhemispheric propagation time by 86.4%. These actions of serotonin were mimicked by the activation of either 5-HT1B or 5-HT2A receptors, but not by the activation of the 5-HT1A subtype. These findings provide further knowledge about the propagation of synchronic electrical activity in the cerebral cortex, including its modulation by serotonin, and suggest the presence of deep differences between the ACC and RSC in the structure of the local cortical microcircuits underlying the propagation of synchronous discharges.

Back to front: cerebellar connections and interactions with the prefrontal cortex

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Thomas C Watson

2014-02-01

Full Text Available Although recent neuroanatomical evidence has demonstrated closed-loop connectivity between prefrontal cortex and the cerebellum, the physiology of cerebello-cerebral circuits and the extent to which cerebellar output modulates neuronal activity in neocortex during behavior remain relatively unexplored. We show that electrical stimulation of the contralateral cerebellar fastigial nucleus (FN in awake, behaving rats evokes distinct local field potential (LFP responses (onset latency ~13 ms in the prelimbic (PrL subdivision of the medial prefrontal cortex. Trains of FN stimulation evoke heterogeneous patterns of response in putative pyramidal cells in frontal and prefrontal regions in both urethane-anaesthetized and awake, behaving rats. However, the majority of cells showed decreased firing rates during stimulation and subsequent rebound increases; more than 90% of cells showed significant changes in response. Simultaneous recording of on-going LFP activity from FN and PrL while rats were at rest or actively exploring an open field arena revealed significant network coherence restricted to the theta frequency range (5-10 Hz. Granger causality analysis indicated that this coherence was significantly directed from cerebellum to PrL during active locomotion. Our results demonstrate the presence of a cerebello-prefrontal pathway in rat and reveal behaviorally dependent coordinated network activity between the two structures, which could facilitate transfer of sensorimotor information into ongoing neocortical processing during goal directed behaviors.

Predictive value of brain SPECT with 99 technetium - MIBI for differentiation of histologic grade brain gliomas

International Nuclear Information System (INIS)

León Castellón, Roberto; Martín Escuela, Juan Miguel; López Díaz, Ing. Adlin; Salva Camaño, Silvia; Gómez Viera, DrC. Nelson; San Pedro, Aley Palau; Castro Jiménez, Mayté

2016-01-01

Diagnosis and treatment of primary tumors of the nervous system remain difficult and are a challenge to be addressed in a multidisciplinary way. In order to determine the usefulness of brain SPECT 99 Tc MIBI to differentiate histologic grade brain gliomas - Frequently brain tumors - they were studied 68 patients with this technique. A dynamic study first step in AP and lateral view was performed, and a SPECT at 20 minutes post-administration and at 2 hours late views. the post-surgical histological study of injuries was used as control. several imaging parameters such as the absolute activity of 99m Tc-MIBI were calculated both early and late phase, cortex contralateral tumor rates; pituitary tumor; choroid plexus tumor and Reason Late / Early phase tumor index / contralateral cortex tumor volume functional phase, the volume concentration of MIBI activity in the tumor and the retention rate of the radiopharmaceutical. Of the 68 patients studied, 11 were high-grade tumors and 57 low grade. The cortex contralateral tumor in late stage index showed a negative satisfactory sensitivity of 98.6% and specificity 77.1%, positive predictive value (PPV) of 48.2% and (NPV) of 99.8%. The reason late stage / early in the index tumor / contralateral cortex showed values ​​in turn 96.3%, 98.7%, 98.8% and 98.8% sensitivity, specificity, PPV and NPV respectively. The retention rate showed a 99% sensitivity, 89% specificity and PPV, NPV of 95% and 99% respectively. Conclusion: The combination cortex contralateral tumor rate in late stage, the reason late stage / early stage tumor index / contralateral cortex and the retention rate of the radiopharmaceutical are the most useful parameters to predict histologic grade of brain gliomas. (author)

The origin of activity in the biceps brachii muscle during voluntary contractions of the contralateral elbow flexor muscles

NARCIS (Netherlands)

Zijdewind, Inge; Butler, Jane E.; Gandevia, Simon C.; Taylor, Janet L.

During strong voluntary contractions, activity is not restricted to the target muscles. Other muscles, including contralateral muscles, often contract. We used transcranial magnetic stimulation (TMS) to analyse the origin of these unintended contralateral contractions (termed "associated"

Thalamic, brainstem, and cerebellar glucose metabolism in the hemiplegic monkey

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Shimoyama, I.; Dauth, G.W.; Gilman, S.; Frey, K.A.; Penney, J.B. Jr.

1988-12-01

Unilateral ablation of cerebral cortical areas 4 and 6 of Brodmann in the macaque monkey results in a contralateral hemiplegia that resolves partially with time. During the phase of dense hemiplegia, local cerebral metabolic rate for glucose (1CMRG1c) is decreased significantly in most of the thalamic nuclei ipsilateral to the ablation, and there are slight contralateral decreases. The lCMRGlc is reduced bilaterally in most of the brainstem nuclei and bilaterally in the deep cerebellar nuclei, but only in the contralateral cerebellar cortex. During the phase of partial motor recovery, lCMRGlc is incompletely restored in many of the thalamic nuclei ipsilateral to the ablation and completely restored in the contralateral nuclei. In the brainstem and deep cerebellar nuclei, poor to moderate recovery occurs bilaterally. Moderate recovery occurs in the contralateral cerebellar cortex. The findings demonstrate that a unilateral cerebral cortical lesion strongly affects lCMRGlc in the thalamus ipsilaterally and in the cerebellar cortex contralaterally, but in the brainstem bilaterally. Partial recovery of lCMRGlc accompanies the progressive motor recovery. The structures affected include those with direct, and also those with indirect, connections to the areas ablated.

Concentrated pitch discrimination modulates auditory brainstem responses during contralateral noise exposure.

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Ikeda, Kazunari; Sekiguchi, Takahiro; Hayashi, Akiko

2010-03-31

This study examined a notion that auditory discrimination is a requisite for attention-related modulation of the auditory brainstem response (ABR) during contralateral noise exposure. Given that the right ear was exposed continuously with white noise at an intensity of 60-80 dB sound pressure level, tone pips at 80 dB sound pressure level were delivered to the left ear through either single-stimulus or oddball procedures. Participants conducted reading (ignoring task) and counting target tones (attentive task) during stimulation. The oddball but not the single-stimulus procedures elicited task-related modulations in both early (ABR) and late (processing negativity) event-related potentials simultaneously. The elicitation of the attention-related ABR modulation during contralateral noise exposure is thus considered to require auditory discrimination and have the corticofugal nature evidently.

Combined SCI and TBI: recovery of forelimb function after unilateral cervical spinal cord injury (SCI) is retarded by contralateral traumatic brain injury (TBI), and ipsilateral TBI balances the effects of SCI on paw placement.

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Inoue, Tomoo; Lin, Amity; Ma, Xiaokui; McKenna, Stephen L; Creasey, Graham H; Manley, Geoffrey T; Ferguson, Adam R; Bresnahan, Jacqueline C; Beattie, Michael S

2013-10-01

A significant proportion (estimates range from 16 to 74%) of patients with spinal cord injury (SCI) have concomitant traumatic brain injury (TBI), and the combination often produces difficulties in planning and implementing rehabilitation strategies and drug therapies. For example, many of the drugs used to treat SCI may interfere with cognitive rehabilitation, and conversely drugs that are used to control seizures in TBI patients may undermine locomotor recovery after SCI. The current paper presents an experimental animal model for combined SCI and TBI to help drive mechanistic studies of dual diagnosis. Rats received a unilateral SCI (75 kdyn) at C5 vertebral level, a unilateral TBI (2.0 mm depth, 4.0 m/s velocity impact on the forelimb sensori-motor cortex), or both SCI+TBI. TBI was placed either contralateral or ipsilateral to the SCI. Behavioral recovery was examined using paw placement in a cylinder, grooming, open field locomotion, and the IBB cereal eating test. Over 6weeks, in the paw placement test, SCI+contralateral TBI produced a profound deficit that failed to recover, but SCI+ipsilateral TBI increased the relative use of the paw on the SCI side. In the grooming test, SCI+contralateral TBI produced worse recovery than either lesion alone even though contralateral TBI alone produced no observable deficit. In the IBB forelimb test, SCI+contralateral TBI revealed a severe deficit that recovered in 3 weeks. For open field locomotion, SCI alone or in combination with TBI resulted in an initial deficit that recovered in 2 weeks. Thus, TBI and SCI affected forelimb function differently depending upon the test, reflecting different neural substrates underlying, for example, exploratory paw placement and stereotyped grooming. Concurrent SCI and TBI had significantly different effects on outcomes and recovery, depending upon laterality of the two lesions. Recovery of function after cervical SCI was retarded by the addition of a moderate TBI in the contralateral

Intracellular responses to frequency modulated tones in the dorsal cortex of the mouse inferior colliculus

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Ruediger eGeis

2013-01-01

Full Text Available Frequency modulations occur in many natural sounds, including vocalizations. The neuronal response to frequency modulated (FM stimuli has been studied extensively in different brain areas, with an emphasis on the auditory cortex and the central nucleus of the inferior colliculus. Here, we measured the responses to FM sweeps in whole-cell recordings from neurons in the dorsal cortex of the mouse inferior colliculus. Both up- and downward logarithmic FM sweeps were presented at two different speeds to both the ipsi- and the contralateral ear. Based on the number of action potentials that were fired, between 10-24% of cells were selective for rate or direction of the FM sweeps. A somewhat lower percentage of cells, 6-21%, showed selectivity based on EPSP size. To study the mechanisms underlying the generation of FM selectivity, we compared FM responses with responses to simple tones in the same cells. We found that if pairs of neurons responded in a similar way to simple tones, they generally also responded in a similar way to FM sweeps. Further evidence that FM selectivity can be generated within the dorsal cortex was obtained by reconstructing FM sweeps from the response to simple tones using three different models. In about half of the direction selective neurons the selectivity was generated by spectrally asymmetric synaptic inhibition. In addition, evidence for direction selectivity based on the timing of excitatory responses was also obtained in some cells. No clear evidence for the local generation of rate selectivity was obtained. We conclude that FM direction selectivity can be generated within the dorsal cortex of the mouse inferior colliculus by multiple mechanisms.

Language processing of auditory cortex revealed by functional magnetic resonance imaging in presbycusis patients.

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Chen, Xianming; Wang, Maoxin; Deng, Yihong; Liang, Yonghui; Li, Jianzhong; Chen, Shiyan

2016-01-01

Contralateral temporal lobe activation decreases with aging, regardless of hearing status, with elderly individuals showing reduced right ear advantage. Aging and hearing loss possibly lead to presbycusis speech discrimination decline. To evaluate presbycusis patients' auditory cortex activation under verbal stimulation. Thirty-six patients were enrolled: 10 presbycusis patients (mean age = 64 years, range = 60-70), 10 in the healthy aged group (mean age = 66 years, range = 60-70), and 16 young healthy volunteers (mean age = 25 years, range = 23-28). These three groups underwent simultaneous 1 kHz and 90 dB single-syllable word stimuli and (blood-oxygen-level-dependent functional magnetic resonance imaging) BOLD fMRI examinations. The main activation regions were superior temporal and middle temporal gyrus. For all aged subjects, the right region of interest (ROI) activation volume was decreased compared with the young group. With left ear stimulation, bilateral ROI activation intensity held. With right ear stimulation, the aged group's activation intensity was higher. Using monaural stimulation in the young group, contralateral temporal lobe activation volume and intensity were higher vs ipsilateral, while they were lower in the aged and presbycusis groups. On left and right ear auditory tasks, the young group showed right ear advantage, while the aged and presbycusis groups showed reduced right ear advantage.

Role of Active Listening and Listening Effort on Contralateral Suppression of Transient Evoked Otoacousic Emissions

OpenAIRE

Kalaiah, Mohan Kumar; Theruvan, Nikhitha B; Kumar, Kaushlendra; Bhat, Jayashree S

2017-01-01

Background and Objectives The present study aimed to investigate the effect of active listening and listening effort on the contralateral suppression of transient evoked otoacoustic emissions (CSTEOAEs). Subjects and Methods Twenty eight young adults participated in the study. Transient evoked otoacoustic emissions (TEOAEs) were recorded using ?linear? clicks at 60 dB peSPL, in three contralateral noise conditions. In condition 1, TEOAEs were obtained in the presence of white noise in the con...

Prior contralateral amputation predicts worse outcomes for lower extremity bypasses performed in the intact limb.

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Baril, Donald T; Goodney, Philip P; Robinson, William P; Nolan, Brian W; Stone, David H; Li, YouFu; Cronenwett, Jack L; Schanzer, Andres

2012-08-01

To date, history of a contralateral amputation as a potential predictor of outcomes after lower extremity bypass (LEB) for critical limb ischemia (CLI) has not been studied. We sought to determine if a prior contralateral lower extremity amputation predicts worse outcomes in patients undergoing LEB in the remaining intact limb. A retrospective analysis of all patients undergoing infrainguinal LEB for CLI between 2003 and 2010 within hospitals comprising the Vascular Study Group of New England was performed. Patients were stratified according to whether or not they had previously undergone a contralateral major or minor amputation before LEB. Primary end points included major amputation and graft occlusion at 1 year postoperatively. Secondary end points included in-hospital major adverse events, discharge status, and mortality at 1 year. Of 2636 LEB procedures, 228 (8.6%) were performed in the setting of a prior contralateral amputation. Patients with a prior amputation compared to those without were younger (66.5 vs 68.7; P = .034), more like to have congestive heart failure (CHF; 25% vs 16%; P = .002), hypertension (94% vs 85%; P = .015), renal insufficiency (26% vs 14%; P = .0002), and hemodialysis-dependent renal failure (14% vs 6%; P = .0002). They were also more likely to be nursing home residents (8.0% vs 3.6%; P = .036), less likely to ambulate without assistance (41% vs 80%; P < .0002), and more likely to have had a prior ipsilateral bypass (20% vs 12%; P = .0005). These patients experience increased in-hospital major adverse events, including myocardial infarction (MI; 8.9% vs 4.2%; P = .002), CHF (6.1% vs 3.4%; P = .044), deterioration in renal function (9.0% vs 4.7%; P = .006), and respiratory complications (4.2% vs 2.3%; P = .034). They were less likely to be discharged home (52% vs 72%; P < .0001) and less likely to be ambulatory on discharge (25% vs 55%; P < .0001). Although patients with a prior contralateral amputation experienced increased rates of

Metabolite changes in the ipsilateral and contralateral cerebral hemispheres in rats with middle cerebral artery occlusion

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Lei Ruan

2017-01-01

Full Text Available Cerebral ischemia not only causes pathological changes in the ischemic areas but also induces a series of secondary changes in more distal brain regions (such as the contralateral cerebral hemisphere. The impact of supratentorial lesions, which are the most common type of lesion, on the contralateral cerebellum has been studied in patients by positron emission tomography, single photon emission computed tomography, magnetic resonance imaging and diffusion tensor imaging. In the present study, we investigated metabolite changes in the contralateral cerebral hemisphere after supratentorial unilateral ischemia using nuclear magnetic resonance spectroscopy-based metabonomics. The permanent middle cerebral artery occlusion model of ischemic stroke was established in rats. Rats were randomly divided into the middle cerebral artery occlusion 1-, 3-, 9- and 24-hour groups and the sham group. 1H nuclear magnetic resonance spectroscopy was used to detect metabolites in the left and right cerebral hemispheres. Compared with the sham group, the concentrations of lactate, alanine, γ-aminobutyric acid, choline and glycine in the ischemic cerebral hemisphere were increased in the acute stage, while the concentrations of N-acetyl aspartate, creatinine, glutamate and aspartate were decreased. This demonstrates that there is an upregulation of anaerobic glycolysis (shown by the increase in lactate, a perturbation of choline metabolism (suggested by the increase in choline, neuronal cell damage (shown by the decrease in N-acetyl aspartate and neurotransmitter imbalance (evidenced by the increase in γ-aminobutyric acid and glycine and by the decrease in glutamate and aspartate in the acute stage of cerebral ischemia. In the contralateral hemisphere, the concentrations of lactate, alanine, glycine, choline and aspartate were increased, while the concentrations of γ-aminobutyric acid, glutamate and creatinine were decreased. This suggests that there is a

Posterior insular cortex - a site of vestibular-somatosensory interaction?

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Baier, Bernhard; Zu Eulenburg, Peter; Best, Christoph; Geber, Christian; Müller-Forell, Wibke; Birklein, Frank; Dieterich, Marianne

2013-09-01

Background In previous imaging studies the insular cortex (IC) has been identified as an essential part of the processing of a wide spectrum of perception and sensorimotor integration. Yet, there are no systematic lesion studies in a sufficient number of patients examining whether processing of vestibular and the interaction of somatosensory and vestibular signals take place in the IC. Methods We investigated acute stroke patients with lesions affecting the IC in order to fill this gap. In detail, we explored signs of a vestibular tone imbalance such as the deviation of the subjective visual vertical (SVV). We applied voxel-lesion behaviour mapping analysis in 27 patients with acute unilateral stroke. Results Our data demonstrate that patients with lesions of the posterior IC have an abnormal tilt of SVV. Furthermore, re-analysing data of 20 patients from a previous study, we found a positive correlation between thermal perception contralateral to the stroke and the severity of the SVV tilt. Conclusions We conclude that the IC is a sensory brain region where different modalities might interact.

Histological evidence of testicular dysgenesis in contralateral biopsies from 218 patients with testicular germ cell cancer

DEFF Research Database (Denmark)

Hoei-Hansen, Christina E; Holm, Mette; Rajpert-De Meyts, Ewa

2003-01-01

dysgenesis, microscopic dysgenetic features were quantified in contralateral testicular biopsies in patients with a testicular germ cell tumour. Two hundred and eighty consecutive contralateral testicular biopsies from Danish patients with testicular cancer diagnosed in 1998-2001 were evaluated...... retrospectively. Two hundred and eighteen specimens were subsequently included in this study, after 63 patients who did not meet inclusion criteria had to be excluded. The presence of carcinoma in situ (which is believed to originate from transformed gonocytes) was detected in 8.7% of biopsies. The incidence...... patients, areas with immature and morphologically distorted tubules were also noted. Spermatogenesis was qualitatively normal in 51.4%, whereas 11.5% had very poor or absent spermatogenesis. It is concluded that microscopic testicular dysgenesis is a frequent feature in contralateral biopsies from patients...

Histological evidence of testicular dysgenesis in contralateral biopsies from 218 patients with testicular germ cell cancer

DEFF Research Database (Denmark)

Hoei-Hansen, Christina E; Holm, Mette; Rajpert-De Meyts, Ewa

2003-01-01

This study was prompted by a hypothesis that testicular germ cell cancer may be aetiologically linked to other male reproductive abnormalities as a part of the so-called 'testicular dysgenesis syndrome' (TDS). To corroborate the hypothesis of a common association of germ cell cancer with testicular...... dysgenesis, microscopic dysgenetic features were quantified in contralateral testicular biopsies in patients with a testicular germ cell tumour. Two hundred and eighty consecutive contralateral testicular biopsies from Danish patients with testicular cancer diagnosed in 1998-2001 were evaluated...... presenting with testicular germ cell neoplasms of the adolescent and young type. The findings therefore support the hypothesis that this cancer is part of a testicular dysgenesis syndrome. The presence of contralateral carcinoma in situ was higher in the present study than previously reported....

結合振動子系によって表現された特徴統合と結合錯誤の神経回路網モデル

OpenAIRE

浅川, 伸一

1993-01-01

An artificial neural network model for explaining the feature integration and the illusory conjunction was proposed. This model was implemented by the coupled oscillating neurons according to the synchronization hypothesis. Compared with other models proposed previously, the prominent features in this model are:1. The visual cortex neurons have the retinotopical maps which represent the input corresponding to its location.2. Pulvinar neurons reciprocally connecting visual cortices facilitate ...

Unilateral hydronephrosis with congenital absence of contralateral kidney in children

International Nuclear Information System (INIS)

Muren, C.; Wikstad, I.

1988-01-01

The case histories of six children with absence of functioning renal parenchyma on one side and dilatation of the contralateral pelvis are reviewed. The hydronephrosis was obstructive in two cases. In the others no cause could be found. The development of this combination of renal malformations is discussed against an embryologic background. (orig.)

Changes in ipsilateral motor cortex activity during a unilateral isometric finger task are dependent on the muscle contraction force

International Nuclear Information System (INIS)

Shibuya, Kenichi; Kuboyama, Naomi; Tanaka, Junya

2014-01-01

It is possible to examine bilateral primary motor cortex (M1) activation during a sustained motor task using near-infrared spectroscopy (NIRS), in which it is assumed that increased oxygenation reflects cortical activation. The purpose of this study was to examine bilateral M1 activation in response to graded levels of force production during a unilateral finger task. Ten healthy right-handed male subjects participated in this study. NIRS probes were placed over the cortex to measure M1 activity while the subjects performed the finger task. The subjects performed a 10 s finger task at 20%, 40%, and 60% of the maximal voluntary contraction (MVC). Symmetrical activation was found over both M1 areas at all force levels investigated. In the contralateral M1, there were significant differences in oxygenation between 20% and 60% MVC, as well as between 40% and 60% MVC. In the ipsilateral M1, there were significant differences among all force levels. These results indicate the ipsilateral M1 takes part in muscle force control. (paper)

Effects of stimulation parameters and electrode location on thresholds for epidural stimulation of cat motor cortex

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Wongsarnpigoon, Amorn; Grill, Warren M.

2011-12-01

Epidural electrical stimulation (ECS) of the motor cortex is a developing therapy for neurological disorders. Both placement and programming of ECS systems may affect the therapeutic outcome, but the treatment parameters that will maximize therapeutic outcomes and minimize side effects are not known. We delivered ECS to the motor cortex of anesthetized cats and investigated the effects of electrode placement and stimulation parameters on thresholds for evoking motor responses in the contralateral forelimb. Thresholds were inversely related to stimulation frequency and the number of pulses per stimulus train. Thresholds were lower over the forelimb representation in motor cortex (primary site) than surrounding sites (secondary sites), and thresholds at sites 4 mm away. Electrode location and montage influenced the effects of polarity on thresholds: monopolar anodic and cathodic thresholds were not significantly different over the primary site, cathodic thresholds were significantly lower than anodic thresholds over secondary sites and bipolar thresholds were significantly lower with the anode over the primary site than with the cathode over the primary site. A majority of bipolar thresholds were either between or equal to the respective monopolar thresholds, but several bipolar thresholds were greater than or less than the monopolar thresholds of both the anode and cathode. During bipolar stimulation, thresholds were influenced by both electric field superposition and indirect, synaptically mediated interactions. These results demonstrate the influence of stimulation parameters and electrode location during cortical stimulation, and these effects should be considered during the programming of systems for therapeutic cortical stimulation.

Measurement of neurovascular coupling in human motor cortex using simultaneous transcranial doppler (TCD) and electroencephalography (EEG).

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Alam, Monzurul; Ahmed, Ghazanfar; Ling, Yan To; Zheng, Yong-Ping

2018-05-25

Event-related desynchronization (ERD) is a relative power decrease of electroencephalogram (EEG) signals in a specific frequency band during physical motor execution, while transcranial Doppler (TCD) measures cerebral blood flow velocity. The objective of this study was to investigate the neurovascular coupling in the motor cortex by using an integrated EEG and TCD system, and to find any difference in hemodynamic responses in healthy young male and female adults. Approach: 30 healthy volunteers, aged 20-30 years were recruited for this study. The subjects were asked to perform a motor task for the duration of a provided visual cue. Simultaneous EEG and TCD recording was carried out using a new integrated system to detect the ERD arising from the EEG signals, and to measure the mean blood flow velocity of the left and right middle cerebral arteries from bilateral TCD signals. Main Results: The results showed a significant decrease in EEG power in mu band (7.5-12.5 Hz) during the motor task compared to the resting phase. It showed significant increase in desynchronization on the contralateral side of the motor task compared to the ipsilateral side. Mean blood flow velocity during the task phase was significantly higher in comparison with the resting phase at the contralateral side. The results also showed a significantly higher increase in the percentage of mean blood flow velocity in the contralateral side of motor task compared to the ipsilateral side. However, no significant difference in desynchronization, or change of mean blood flow velocity was found between males and females. Significance: A combined TCD-EEG system successfully detects ERD and blood flow velocity in cerebral arteries, and can be used as a useful tool to study neurovascular coupling in the brain. There is no significant difference in the hemodynamic responses in healthy young males and females. © 2018 Institute of Physics and Engineering in Medicine.

Unilateral lesion of dorsal hippocampus in adult rats impairs contralateral long-term potentiation in vivo and spatial memory in the early postoperative phase.

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Li, Hongjie; Wu, Xiaoyan; Bai, Yanrui; Huang, Yan; He, Wenting; Dong, Zhifang

2012-05-01

It is well documented that bilateral hippocampal lesions or unilateral hippocampal lesion at birth causes impairment of contralateral LTP and long-term memory. However, effects of unilateral hippocampal lesion in adults on contralateral in vivo LTP and memory are not clear. We here examined the influence of unilateral electrolytic dorsal hippocampal lesion in adult rats on contralateral LTP in vivo and spatial memory during different postoperative phases. We found that acute unilateral hippocampal lesion had no effect on contralateral LTP. However, contralateral LTP was impaired at 1 week after lesion, and was restored to the control level at postoperative week 4. Similarly, spatial memory was also impaired at postoperative week 1, and was restored at postoperative week 4. In addition, the rats at postoperative week 1 showed stronger spatial exploratory behavior in a novel open-field environment. The sham operation had no effects on contralateral LTP, spatial memory and exploration at either postoperative week 1 or week 4. These results suggest that unilateral dorsal hippocampal lesion in adult rats causes transient contralateral LTP impairment and spatial memory deficit. Copyright © 2012 Elsevier B.V. All rights reserved.

Risk and prognostic significance of metachronous contralateral testicular germ cell tumours

NARCIS (Netherlands)

Schaapveld, M.; van den Belt-Dusebout, A. W.; Gietema, J. A.; de Wit, R.; Horenblas, S.; Witjes, J. A.; Hoekstra, H. J.; Kiemeney, L. A. L. M.; Louwman, W. J.; Ouwens, G. M.; Aleman, B. M. P.; van Leeuwen, F. E.

2012-01-01

BACKGROUND: Testicular germ cell tumour (TGCT) patients are at increased risk of developing a contralateral testicular germ cell tumour (CTGCT). It is unclear whether TGCT treatment affects CTGCT risk. METHODS: The risk of developing a metachronous CTGCT (a CTGCT diagnosed >= 6 months after a

Efficient visual object and word recognition relies on high spatial frequency coding in the left posterior fusiform gyrus: evidence from a case-series of patients with ventral occipito-temporal cortex damage.

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Roberts, Daniel J; Woollams, Anna M; Kim, Esther; Beeson, Pelagie M; Rapcsak, Steven Z; Lambon Ralph, Matthew A

2013-11-01

Recent visual neuroscience investigations suggest that ventral occipito-temporal cortex is retinotopically organized, with high acuity foveal input projecting primarily to the posterior fusiform gyrus (pFG), making this region crucial for coding high spatial frequency information. Because high spatial frequencies are critical for fine-grained visual discrimination, we hypothesized that damage to the left pFG should have an adverse effect not only on efficient reading, as observed in pure alexia, but also on the processing of complex non-orthographic visual stimuli. Consistent with this hypothesis, we obtained evidence that a large case series (n = 20) of patients with lesions centered on left pFG: 1) Exhibited reduced sensitivity to high spatial frequencies; 2) demonstrated prolonged response latencies both in reading (pure alexia) and object naming; and 3) were especially sensitive to visual complexity and similarity when discriminating between novel visual patterns. These results suggest that the patients' dual reading and non-orthographic recognition impairments have a common underlying mechanism and reflect the loss of high spatial frequency visual information normally coded in the left pFG.

Mandibular Corpus Horizontal Distraction in an Edentulous Case and Its Effects on the Contralateral Coronoid Processus-Arcus Zygomaticus Relation

Directory of Open Access Journals (Sweden)

Furkan Erol Karabekmez

2014-05-01

Full Text Available PurposeInteraction between the coronoid processus and the arcus-zygomaticus on contralateral hemi-mandible often drops off the radar in case of distraction osteogenesis of the mandibular corpus. We presented a 42 years old male without any teeth applied to hospital for facial asymmetry, short hemi-mandible and chewing problems.Case2D and 3D computerized tomography and stereo-lithographic models were used for planning, predicting possible movements on the contralateral condyle and anticipate the relation of contralateral coronoid process the with zygomatic arc. Maximum safe amounts of distraction were calculated with cooperation with orthodontics and radiology. The rotation angle on the axis of the contralateral condyle is calculated in order to measure the defect to be corrected to take the maxillary and mandibular midlines to the same plane. Total calculated defect were shortened for preventing any interaction between the coronoid processus and the arcus-zygomaticus on contralateral hemi-mandible.ResultPatient was satisfied and started to use new dentures two months after removal of the distraction device.ConclusionIn order to achieve successful distraction without any problem regarding to opposite side rotation angles of the condyle, and position changes in the coronoid processus, collaboration and multidisciplinary approach are essential with orthodontics and radiologist in case of unilateral mandibular corpus distraction.

Studies of the mechanism of contralateral polyuria after renal artery stenosis.

Science.gov (United States)

Galvez, O G; Roberts, B W; Mishkind, M H; Bay, W H; Ferris, T F

1977-01-01

Acute renal artery stenosis in hydropenic dogs caused a contralateral increase in urine volume and free water clearance without change in glomerular filtration, renal blood flow, or osmolar clearance. The increase in urine volume was not dependent on the development of hypertension since it occurred in animals pretreated with trimethaphan but was dependent upon angiotensin since it was presented with angiotensin blockade with Saralasin. The effect was not caused by angiotensin inhibiting antidiuretic hormone release since the polyuria occurred in hypophysectomized animals receiving a constant infusion of 10 muU/kg per min of aqueous Pitressin. Since the rise in urine volume was associated with an increase in renal vein prostaglandin E concentration and was prevented by pretreatment with indomethacin (5 mg/kg) the results suggest that the rise in plasma angiotensin after renal artery stenosis causes an increase in contralateral prostaglandin E synthesis with resultant antagonism to antidiuretic hormone at the collecting tubule. PMID:845253

Functional MR imaging of cerebral auditory cortex with linguistic and non-linguistic stimulation: preliminary study

International Nuclear Information System (INIS)

Kang, Su Jin; Kim, Jae Hyoung; Shin, Tae Min

1999-01-01

To obtain preliminary data for understanding the central auditory neural pathway by means of functional MR imaging (fMRI) of the cerebral auditory cortex during linguistic and non-linguistic auditory stimulation. In three right-handed volunteers we conducted fMRI of auditory cortex stimulation at 1.5 T using a conventional gradient-echo technique (TR/TE/flip angle: 80/60/40 deg). Using a pulsed tone of 1000 Hz and speech as non-linguistic and linguistic auditory stimuli, respectively, images-including those of the superior temporal gyrus of both hemispheres-were obtained in sagittal plases. Both stimuli were separately delivered binaurally or monoaurally through a plastic earphone. Images were activated by processing with homemade software. In order to analyze patterns of auditory cortex activation according to type of stimulus and which side of the ear was stimulated, the number and extent of activated pixels were compared between both temporal lobes. Biaural stimulation led to bilateral activation of the superior temporal gyrus, while monoaural stimulation led to more activation in the contralateral temporal lobe than in the ipsilateral. A trend toward slight activation of the left (dominant) temporal lobe in ipsilateral stimulation, particularly with a linguistic stimulus, was observed. During both biaural and monoaural stimulation, a linguistic stimulus produced more widespread activation than did a non-linguistic one. The superior temporal gyri of both temporal lobes are associated with acoustic-phonetic analysis, and the left (dominant) superior temporal gyrus is likely to play a dominant role in this processing. For better understanding of physiological and pathological central auditory pathways, further investigation is needed

Blood oxygenation level dependent functional MRI study on the changes of motor cortex in patients with amyotrophic lateral sclerosis

International Nuclear Information System (INIS)

Han Jing; Ma Lin; Lou Xin; Yu Shengyuan; Li Dejun

2008-01-01

Objective: To study the changes of motor cortex in patients with amyotrophic lateral sclerosis (ALS) while executing sequential finger tapping movement by using blood oxygenation level dependent (BOLD) functional MRI. Methods: Fifteen patients with definite or probable ALS and 15 age and gender matched normal controls were enrolled in the BOLD study, and all the subjects were right-handed with no other diseases or any recent medication history. A 3.0 T MR scanner' was employed and gradient echo EPI (GRE-EPI)sequence was used to acquire the functional images. Subjects executed sequential finger tapping movement at a frequency of 1-2 Hz during a block design task. fMRI data were analyzed by using statistical parametric mapping (SPM) 2. Volume of activated brain areas was compared with the use of a Student's t-test. Results: Bilateral primary sensorimotor cortex (PSM), bilateral posterior aspect of premotor area (PA), bilateral supplementary motor area (SMA), contralateral inferior lateral premotor area (ILPA), bilateral parietal region (PAR), and ipsilateral cerebellum showed activation in both ALS patients and normal controls when executing the same motor task. The activation areas in bilateral PSM and bilateral posterior aspect of PA ( right hand ipsilateral activation: ALS (924.5±141.1) mm 3 , control (829.9± 98.4) mm 3 , P=0.05; right hand contralateral activation: ALS (9143.8±702.8) mm 3 , control (8638.8±506.4) mm 3 P 3 , control (902.5±3 184.2)mm , P 3 , control (5934.6±616.4) mm 3 , P 3 , control (4710.7±416.3) mm 3 , P 3 , control (3688.9±672.3) mm 3 , P 3 , control (254.3±84.4) mm 3 , P 3 , control (1689.0±719.6) mm 3 , P<0.05) were significantly larger in ALS patients than in normal controls. Extra activation areas including ipsilateral ILPA, contralateral cerebellum and bilateral posterior limb of internal capsule were only detected in ALS patients. Conclusions: Similar activation areas were seen in both groups while executing the same motor

The benefit of image guidance for the contralateral interhemispheric approach to the lateral ventricle.

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Fronda, Chiara; Miller, Dorothea; Kappus, Christoph; Bertalanffy, Helmut; Sure, Ulrich

2008-06-01

Recently, neurosurgeons have increasingly faced small intracerebral lesions in asymptomatic or minimally symptomatic patients. Here, we evaluated a series of four patients with nearly asymptomatic intraventricular tumors close to the corpus callosum that had been treated with the aid of an image-guided transcallosal approach. Four consecutive patients suffering from left intra- and paraventricular tumors were operated on via a contralateral interhemispheric transcallosal approach with the aid of neuronavigation. Our image-guided system directed: (1) the skin incision, (2) the interhemispheric dissection, and (3) the incision of the corpus callosum. Using the image-guided contralateral interhemispheric transcallosal approach to the left ventricle all lesions have been completely resected without the risk of damage to the dominant hemisphere. The callosal incision was kept as limited as possible (1.2-2.1cm) depending on the size of the tumor. No postoperative neurological or neuropsychological deficit was observed in our series. Neuronavigation facilitates a safe and targeted contralateral interhemispheric transcallosal approach to the dominant hemisphere's lateral ventricle. Our technique minimizes the risk of damage to the dominant hemisphere and requires only a limited opening of the corpus callosum, which might decrease the risk of neuropsychological morbidity.

Motor cortex hand area and speech: implications for the development of language.

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Meister, Ingo Gerrit; Boroojerdi, Babak; Foltys, Henrik; Sparing, Roland; Huber, Walter; Töpper, Rudolf

2003-01-01

Recently a growing body of evidence has suggested that a functional link exists between the hand motor area of the language dominant hemisphere and the regions subserving language processing. We examined the excitability of the hand motor area and the leg motor area during reading aloud and during non-verbal oral movements using transcranial magnetic stimulation (TMS). During reading aloud, but not before or afterwards, excitability was increased in the hand motor area of the dominant hemisphere. This reading effect was found to be independent of the duration of speech. No such effect could be found in the contralateral hemisphere. The excitability of the leg area of the motor cortex remained unchanged during reading aloud. The excitability during non-verbal oral movements was slightly increased in both hemispheres. Our results are consistent with previous findings and may indicate a specific functional connection between the hand motor area and the cortical language network.

Posterior insular cortex – a site of vestibular–somatosensory interaction?

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Baier, Bernhard; zu Eulenburg, Peter; Best, Christoph; Geber, Christian; Müller-Forell, Wibke; Birklein, Frank; Dieterich, Marianne

2013-01-01

Background In previous imaging studies the insular cortex (IC) has been identified as an essential part of the processing of a wide spectrum of perception and sensorimotor integration. Yet, there are no systematic lesion studies in a sufficient number of patients examining whether processing of vestibular and the interaction of somatosensory and vestibular signals take place in the IC. Methods We investigated acute stroke patients with lesions affecting the IC in order to fill this gap. In detail, we explored signs of a vestibular tone imbalance such as the deviation of the subjective visual vertical (SVV). We applied voxel-lesion behaviour mapping analysis in 27 patients with acute unilateral stroke. Results Our data demonstrate that patients with lesions of the posterior IC have an abnormal tilt of SVV. Furthermore, re-analysing data of 20 patients from a previous study, we found a positive correlation between thermal perception contralateral to the stroke and the severity of the SVV tilt. Conclusions We conclude that the IC is a sensory brain region where different modalities might interact. PMID:24392273

Functional recovery in the irradiated kidney following removal of the contralateral unirradiated kidney

International Nuclear Information System (INIS)

Robbins, M.E.C.; Hopewell, J.W.; Golding, S.J.

1986-01-01

Radiation-induced damage to one kidney in the pig causes a fall in total renal function; this would be recognised and lead to a compensatory response in the unirradiated kidney. The presence of the unirradiated contralateral kidney may effectively prevent the irradiated kidney from expressing any potential for repair and/or recovery of function. If this were true then the question would obviously arise, does the irradiated kidney retain some capacity for recovery? In order to answer this question, the contralateral unirradiated kidney was removed from pigs 26 weeks after the irradiation of the other kidney. The subsequent response of the irradiated kidney to nephrectomy was assessed in terms of the changes in renal size and haemodynamics, i.e. GFR and effective renal plasma flow (ERPF). (Auth.)

Motor cortex electrical stimulation augments sprouting of the corticospinal tract and promotes recovery of motor function

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Carmel, Jason B.; Martin, John H.

2014-01-01

The corticospinal system—with its direct spinal pathway, the corticospinal tract (CST) – is the primary system for controlling voluntary movement. Our approach to CST repair after injury in mature animals was informed by our finding that activity drives establishment of connections with spinal cord circuits during postnatal development. After incomplete injury in maturity, spared CST circuits sprout, and partially restore lost function. Our approach harnesses activity to augment this injury-dependent CST sprouting and to promote function. Lesion of the medullary pyramid unilaterally eliminates all CST axons from one hemisphere and allows examination of CST sprouting from the unaffected hemisphere. We discovered that 10 days of electrical stimulation of either the spared CST or motor cortex induces CST axon sprouting that partially reconstructs the lost CST. Stimulation also leads to sprouting of the cortical projection to the magnocellular red nucleus, where the rubrospinal tract originates. Coordinated outgrowth of the CST and cortical projections to the red nucleus could support partial re-establishment of motor systems connections to the denervated spinal motor circuits. Stimulation restores skilled motor function in our animal model. Lesioned animals have a persistent forelimb deficit contralateral to pyramidotomy in the horizontal ladder task. Rats that received motor cortex stimulation either after acute or chronic injury showed a significant functional improvement that brought error rate to pre-lesion control levels. Reversible inactivation of the stimulated motor cortex reinstated the impairment demonstrating the importance of the stimulated system to recovery. Motor cortex electrical stimulation is an effective approach to promote spouting of spared CST axons. By optimizing activity-dependent sprouting in animals, we could have an approach that can be translated to the human for evaluation with minimal delay. PMID:24994971

Malalignment and subchondral bone turnover in contralateral knees of overweight/obese women with unilateral osteoarthritis: implications for bilateral disease.

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Mazzuca, Steven A; Brandt, Kenneth D; Lane, Kathleen A; Chakr, Rafael

2011-11-01

To explore whether the risk of incident tibiofemoral (TF) osteoarthritis (OA) in the radiographically normal contralateral knee of overweight/obese women with unilateral knee OA is mediated by malalignment and/or preceded by increased turnover of subchondral bone. We used data of post hoc analyses from a randomized controlled trial. Cross-sectional analyses evaluated the baseline association between frontal plane alignment and bone turnover in the medial TF compartment in 78 radiographically normal contralateral knees. Longitudinal analyses ascertained whether incident radiographic OA (TF osteophyte formation within 30 months) was associated with malalignment and/or increased bone turnover at baseline. Alignment subcategories (varus/neutral/valgus) were based on the anatomic axis angle. (99m)Tc-methylene diphosphonate uptake in a late-phase bone scan was quantified in regions of interest in the medial tibia (MT) and medial femur (MF) and adjusted for uptake in a reference segment of the ipsilateral tibial shaft (TS). MF and MT uptake in varus contralateral knees was 50-55% greater than in the TS. Adjusted MT uptake in varus contralateral knees was significantly greater than that in neutral and valgus contralateral knees (mean 1.55 versus 1.38 and 1.43, respectively; P < 0.05). Among 69 contralateral knees followed longitudinally, 22 (32%) developed TF OA. Varus angulation was associated with a marginally significant increase in the odds of incident OA (adjusted odds ratio 3.98, P = 0.067). While the small sample size limited our ability to detect statistically significant risk factors, these data suggest that the risk of developing bilateral TF OA in overweight/obese women may be mediated by varus malalignment. Copyright © 2011 by the American College of Rheumatology.

Intermittent θ burst stimulation over primary motor cortex enhances movement-related β synchronisation.

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Hsu, Ya-Fang; Liao, Kwong-Kum; Lee, Po-Lei; Tsai, Yun-An; Yeh, Chia-Lung; Lai, Kuan-Lin; Huang, Ying-Zu; Lin, Yung-Yang; Lee, I-Hui

2011-11-01

The objective of this study is to investigate how transcranial magnetic intermittent theta burst stimulation (iTBS) with a prolonged protocol affects human cortical excitability and movement-related oscillations. Using motor-evoked potentials (MEPs) and movement-related magnetoencephalography (MEG), we assessed the changes of corticospinal excitability and cortical oscillations after iTBS with double the conventional stimulation time (1200 pulses, iTBS1200) over the primary motor cortex (M1) in 10 healthy subjects. Continuous TBS (cTBS1200) and sham stimulation served as controls. iTBS1200 facilitated MEPs evoked from the conditioned M1, while inhibiting MEPs from the contralateral M1 for 30 min. By contrast, cTBS1200 inhibited MEPs from the conditioned M1. Importantly, empirical mode decomposition-based MEG analysis showed that the amplitude of post-movement beta synchronisation (16-26 Hz) was significantly increased by iTBS1200 at the conditioned M1, but was suppressed at the nonconditioned M1. Alpha (8-13 Hz) and low gamma-ranged (35-45 Hz) rhythms were not notably affected. Movement kinetics remained consistent throughout. TBS1200 modulated corticospinal excitability in parallel with the direction of conventional paradigms with modestly prolonged efficacy. Moreover, iTBS1200 increased post-movement beta synchronisation of the stimulated M1, and decreased that of the contralateral M1, probably through interhemispheric interaction. Our results provide insight into the underlying mechanism of TBS and reinforce the connection between movement-related beta synchronisation and corticospinal output. Copyright © 2011 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Is it necessary to use the entire root as a donor when transferring contralateral C7 nerve to repair median nerve?

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Gao, Kai-Ming; Lao, Jie; Guan, Wen-Jie; Hu, Jing-Jing

2018-01-01

If a partial contralateral C 7 nerve is transferred to a recipient injured nerve, results are not satisfactory. However, if an entire contralateral C 7 nerve is used to repair two nerves, both recipient nerves show good recovery. These findings seem contradictory, as the above two methods use the same donor nerve, only the cutting method of the contralateral C 7 nerve is different. To verify whether this can actually result in different repair effects, we divided rats with right total brachial plexus injury into three groups. In the entire root group, the entire contralateral C 7 root was transected and transferred to the median nerve of the affected limb. In the posterior division group, only the posterior division of the contralateral C 7 root was transected and transferred to the median nerve. In the entire root + posterior division group, the entire contralateral C 7 root was transected but only the posterior division was transferred to the median nerve. After neurectomy, the median nerve was repaired on the affected side in the three groups. At 8, 12, and 16 weeks postoperatively, electrophysiological examination showed that maximum amplitude, latency, muscle tetanic contraction force, and muscle fiber cross-sectional area of the flexor digitorum superficialis muscle were significantly better in the entire root and entire root + posterior division groups than in the posterior division group. No significant difference was found between the entire root and entire root + posterior division groups. Counts of myelinated axons in the median nerve were greater in the entire root group than in the entire root + posterior division group, which were greater than the posterior division group. We conclude that for the same recipient nerve, harvesting of the entire contralateral C 7 root achieved significantly better recovery than partial harvesting, even if only part of the entire root was used for transfer. This result indicates that the entire root should be used as a

Effect of ligamenta flava hypertrophy on lumbar disc herniation with contralateral symptoms and signs: a clinical and morphometric study

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Yildizhan, Ahmet; Atar, Elmas K.; Yaycioglu, Soner; Gocmen-Mas, Nuket; Yazici, Canan

2010-01-01

Introduction The purpose of this study was to determine whether ligamentum flavum hypertrophy among disc herniated patients causes contralateral pain symptoms. For this reason we measured the thickness of the ligament in disc herniated patients with ipsilateral or contralateral symptoms. Material and methods Two hundred disc herniated patients with ipsilateral symptoms as group I were compared with five disc herniated patients with only contralateral symptoms as group II. Ligamenta flava thicknesses and spinal canal diameters of both groups were measured on magnetic resonance imaging (MRI) with a micro-caliper. Results Both groups underwent surgery only on the disc herniated side. The total thicknesses of the ligamenta flava in group II was thicker than in group I. There was no spinal stenosis in either group and no significance difference between the groups. Statistically significant differences were found for both ipsilateral and contralateral thickness of the ligament flava in both groups. We also compared thickness of the ligamenta flava for each level of disc herniation in group I; ligamenta flava hypertrophy was more common at L3-L4 and L4-L5 levels of vertebrae in females. Conclusions Aetiology of contralateral sciatica among disc herniated patients may be related to hypertrophy of the ligamenta flava, especially on the opposite side. Surgical approaches of the disc herniated side alone may be sufficient for a good outcome. PMID:22371809

A review of clinical and histological parameters associated with contralateral neck metastases in oral squamous cell carcinoma

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Fan, Song; Tang, Qiong-lan; Lin, Ying-jin; Chen, Wei-liang; Li, Jin-song; Huang, Zhi-quan; Yang, Zhao-hui; Wang, You-yuan; Zhang, Da-ming; Wang, Hui-jing; Dias-Ribeiro, Eduardo; Cai, Qiang; Wang, Lei

2011-01-01

Oral squamous cell carcinoma (OSCC) has a high incidence of cervical micrometastases and sometimes metastasizes contralaterally because of the rich lymphatic intercommunications relative to submucosal plexus of oral cavity that freely communicate across the midline, and it can facilitate the spread of neoplastic cells to any area of the neck consequently. Clinical and histopathologic factors continue to provide predictive information to contralateral neck metastases (CLNM) in OSCC, which determine prophylactic and adjuvant treatments for an individual patient. This review describes the predictive value of clinical-histopathologic factors, which relate to primary tumor and cervical lymph nodes, and surgical dissection and adjuvant treatments. In addition, the indications for elective contralateral neck dissection and adjuvant radiotherapy (aRT) and strategies for follow-up are offered, which is strongly focused by clinicians to prevent later CLNM and poor prognosis subsequently. PMID:22010576

Functional effects of renal artery stent placement on treated and contralateral kidneys.

NARCIS (Netherlands)

Leertouwer, T.C.; Derkx, F.H.M.; Pattynama, P.M.; Deinum, J.; Dijk, L.C. van; Schalekamp, M.A.D.H.

2002-01-01

BACKGROUND: This study examined the effects of stent placement for renal artery stenosis on the function of treated and contralateral kidneys. METHODS: Eighteen patients who underwent stent placement for unilateral renal artery stenosis presenting with hypertension and/or renal failure were studied

The Aortic Bifurcation Angle as a Factor in Application of the Outback for Femoropopliteal Lesions in Ipsilateral Versus Contralateral Approaches.

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Raskin, Daniel; Khaitovich, Boris; Balan, Shmuel; Silverberg, Daniel; Halak, Moshe; Rimon, Uri

2018-01-01

To assess the technical success of the Outback reentry device in contralateral versus ipsilateral approaches for femoropopliteal arterial occlusion. A retrospective review of patients treated for critical limb ischemia (CLI) using the Outback between January 2013 and July 2016 was performed. Age, gender, length and site of the occlusion, approach site, aortic bifurcation angle, and reentry site were recorded. Calcification score was assigned at both aortic bifurcation and reentry site. Technical success was assessed. During the study period, a total of 1300 endovascular procedures were performed on 489 patients for CLI. The Outback was applied on 50 femoropopliteal chronic total occlusions. Thirty-nine contralateral and 11 ipsilateral antegrade femoral were accessed. The device was used successfully in 41 patients (82%). There were nine failures, all in the contralateral approach group. Six due to inability to deliver the device due to acute aortic bifurcation angle and three due to failure to achieve luminal reentry. Procedural success was significantly affected by the aortic bifurcation angle (p = 0.013). The Outback has high technical success rates in treatment of femoropopliteal occlusion, when applied from either an ipsi- or contralateral approach. When applied in contralateral access, acute aortic bifurcation angle predicts procedural failure.

Effect of ipsilateral ureteric obstruction on contralateral kidney and role of renin angiotensin system blockade on renal recovery in experimentally induced unilateral ureteric obstruction

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Shasanka S Panda

2013-01-01

Full Text Available Aims: To study, the effects of ipsilateral ureteric obstruction on contralateral kidney and the role of renin angiotensin system (RAS blockade on renal recovery in experimentally induced unilateral ureteric obstruction. Materials and Methods: Unilateral upper ureteric obstruction was created in 96 adult Wistar rats that were reversed after pre-determined intervals. Losartan and Enalapril were given to different subgroups of rats following relief of obstruction. Results: The severity of dilatation on the contralateral kidney varied with duration of ipsilateral obstruction longer the duration more severe the dilatation. There is direct correlation between renal parenchymal damage, pelvi-ureteric junction (PUJ fibrosis, inflammation and severity of pelvi-calyceal system dilatation of contralateral kidney with duration of ipsilateral PUJ obstruction. Conclusions: Considerable injury is also inflicted to the contralateral normal kidney while ipsilateral kidney remains obstructed. Use of RAS blocking drugs has been found to significantly improve renal recovery on the contralateral kidney. It can, thus, be postulated that contralateral renal parenchymal injury was mediated through activation of RAS.

Improving ideomotor limb apraxia by electrical stimulation of the left posterior parietal cortex.

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Bolognini, Nadia; Convento, Silvia; Banco, Elisabetta; Mattioli, Flavia; Tesio, Luigi; Vallar, Giuseppe

2015-02-01

Limb apraxia, a deficit of planning voluntary gestures, is most frequently caused by damage to the left hemisphere, where, according to an influential neurofunctional model, gestures are planned, before being executed through the motor cortex of the hemisphere contralateral to the acting hand. We used anodal transcranial direct current stimulation delivered to the left posterior parietal cortex (PPC), the right motor cortex (M1), and a sham stimulation condition, to modulate the ability of six left-brain-damaged patients with ideomotor apraxia, and six healthy control subjects, to imitate hand gestures, and to perform skilled hand movements using the left hand. Transcranial direct current stimulation delivered to the left PPC reduced the time required to perform skilled movements, and planning, but not execution, times in imitating gestures, in both patients and controls. In patients, the amount of decrease of planning times brought about by left PPC transcranial direct current stimulation was influenced by the size of the parietal lobe damage, with a larger parietal damage being associated with a smaller improvement. Of interest from a clinical perspective, left PPC stimulation also ameliorated accuracy in imitating hand gestures in patients. Instead, transcranial direct current stimulation to the right M1 diminished execution, but not planning, times in both patients and healthy controls. In conclusion, by using a transcranial stimulation approach, we temporarily improved ideomotor apraxia in the left hand of left-brain-damaged patients, showing a role of the left PPC in planning gestures. This evidence opens up novel perspectives for the use of transcranial direct current stimulation in the rehabilitation of limb apraxia. © The Author (2014). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

SPET monitoring of perfusion changes in auditory cortex following mono- and multi-frequency stimuli

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De Rossi, G. [Nuclear Medicine Inst., Policlinico A. Gemelli, Rome (Italy); Paludetti, G. [Otorhinolaryngology Inst., Policlinico A. Gemelli, Rome (Italy); Di Nardo, W. [Otorhinolaryngology Inst., Policlinico A. Gemelli, Rome (Italy); Calcagni, M.L. [Nuclear Medicine Inst., Policlinico A. Gemelli, Rome (Italy); Di Giuda, D. [Nuclear Medicine Inst., Policlinico A. Gemelli, Rome (Italy); Almadori, G. [Otorhinolaryngology Inst., Policlinico A. Gemelli, Rome (Italy); Galli, J. [Otorhinolaryngology Inst., Policlinico A. Gemelli, Rome (Italy)

1996-08-01

In order to assess the relationship between auditory cortex perfusion and the frequency of acoustic stimuli, twenty normally-hearing subjects underwent cerebral SPET. In 10 patients a multi-frequency stimulus (250-4000 Hz at 40 dB SL) was delivered, while 10 subjects were stimulated with a 500 Hz pure tone at 40 dB SL. The prestimulation SPET was subtracted from poststimulation study and auditory cortex activation was expressed as percent increments. Contralateral cortex was the most active area with multifrequency and monofrequency stimuli as well. A clear demonstration of a tonotopic distribution of acoustic stimuli in the auditory cortex was achieved. In addition, the accessory role played by homolateral accoustic areas was confirmed. The results of the present research support the hypothesis that brain SPET may be useful to obtain semiquantitative reliable information on low frequency auditory level in profoundly deaf patients. This may be achieved comparing the extension of the cortical areas activated by high-intensity multifrequency stimuli. (orig.) [Deutsch] Zur Aufklaerung der Beziehung von regionaler Perfusion des auditorischen Kortex und Frequenz des akustischen Stimulus wurden 20 Normalpatienten mit Hilfe von Hirn-SPECT untersucht. Bei je 10 Patienten wurde ein Multifrequenzstimulus (250-2000 Hz bei 60 dB) bzw. ein Monofrequenzstimulus (500 Hz bei 60 dB) verwendet. Die vor der Stimulation akquirierten SPECT-Daten wurden jeweils von den nach der Stimulation akquirierten SPECT-Daten abgezogen und die aditorische Kortexaktivation als prozentuale Steigerung ausgedrueckt. Der kontralaterale Kortex war das am staerksten aktivierte Areal sowohl bei der Multifrequenz- als auch bei der Monofrequenzstimulation. Es konnte eine klare tonotopische Verteilung der akustischen Stimuli im auditorischen Koretx demonstriert werden. Zusaetzlich konnte die akzessorische Rolle des homolateralen akustischen Kortex bestaetigt werden. Die Ergebnisse dieser Studie unterstuetzen

Neuropathic Pain Causes Pyramidal Neuronal Hyperactivity in the Anterior Cingulate Cortex

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Ruohe Zhao

2018-04-01

Full Text Available The anterior cingulate cortex (ACC is thought to be important for acute pain perception as well as the development of chronic pain after peripheral nerve injury. Nevertheless, how ACC neurons respond to sensory stimulation under chronic pain states is not well understood. Here, we used an in vivo two-photon imaging technique to monitor the activity of individual neurons in the ACC of awake, head restrained mice. Calcium imaging in the dorsal ACC revealed robust somatic activity in layer 5 (L5 pyramidal neurons in response to peripheral noxious stimuli, and the degree of evoked activity was correlated with the intensity of noxious stimulation. Furthermore, the activation of ACC neurons occurred bilaterally upon noxious stimulation to either contralateral or ipsilateral hind paws. Notably, with nerve injury-induced neuropathic pain in one limb, L5 pyramidal neurons in both sides of the ACC showed enhanced activity in the absence or presence of pain stimuli. These results reveal hyperactivity of L5 pyramidal neurons in the bilateral ACC during the development of neuropathic pain.

Role of Active Listening and Listening Effort on Contralateral Suppression of Transient Evoked Otoacousic Emissions.

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Kalaiah, Mohan Kumar; Theruvan, Nikhitha B; Kumar, Kaushlendra; Bhat, Jayashree S

2017-04-01

The present study aimed to investigate the effect of active listening and listening effort on the contralateral suppression of transient evoked otoacoustic emissions (CSTEOAEs). Twenty eight young adults participated in the study. Transient evoked otoacoustic emissions (TEOAEs) were recorded using 'linear' clicks at 60 dB peSPL, in three contralateral noise conditions. In condition 1, TEOAEs were obtained in the presence of white noise in the contralateral ear. While, in condition 2, speech was embedded into white noise at +3, -3, and -9 dB signal-to-noise ratio (SNR) and delivered to the contralateral ear. The SNR was varied to investigate the effect of listening effort on the CSTEOAE. In condition 3, speech was played backwards and embedded into white noise at -3 dB SNR. The conditions 1 and 3 served as passive listening condition and the condition 2 served as active listening condition. In active listening condition, the participants categorized the words in to two groups (e.g., animal and vehicle). CSTEOAE was found to be largest in the presence of white noise, and the amount of CSTEOAE was not significantly different between active and passive listening conditions (condition 2 and 3). Listening effort had an effect on the CSTEOAE, the amount of suppression increased with listening effort, when SNR was decreased from +3 dB to -3 dB. However, when the SNR was further reduced to -9 dB, there was no further increase in the amount of CSTEOAE, instead there was a reduction in the amount of suppression. The findings of the present study show that listening effort might affect CSTEOAE.

Hemispheric differences in the voluntary control of spatial attention: direct evidence for a right-hemispheric dominance within frontal cortex.

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Duecker, Felix; Formisano, Elia; Sack, Alexander T

2013-08-01

Lesion studies in neglect patients have inspired two competing models of spatial attention control, namely, Heilman's "hemispatial" theory and Kinsbourne's "opponent processor" model. Both assume a functional asymmetry between the two hemispheres but propose very different mechanisms. Neuroimaging studies have identified a bilateral dorsal frontoparietal network underlying voluntary shifts of spatial attention. However, lateralization of attentional processes within this network has not been consistently reported. In the current study, we aimed to provide direct evidence concerning the functional asymmetry of the right and left FEF during voluntary shifts of spatial attention. To this end, we applied fMRI-guided neuronavigation to disrupt individual FEF activation foci with a longer-lasting inhibitory patterned TMS protocol followed by a spatial cueing task. Our results indicate that right FEF stimulation impaired the ability of shifting spatial attention toward both hemifields, whereas the effects of left FEF stimulation were limited to the contralateral hemifield. These results provide strong direct evidence for right-hemispheric dominance in spatial attention within frontal cortex supporting Heilman's "hemispatial" theory. This complements previous TMS studies that generally conform to Kinsbourne's "opponent processor" model after disruption of parietal cortex, and we therefore propose that both theories are not mutually exclusive.

Serious neonatal airway obstruction with massive congenital sublingual ranula and contralateral occurrence

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Manish M. George

2015-06-01

Conclusions: The prenatal diagnosis of congenital ranulas have been seldom reported, with no reported cases of contralateral occurrence and airway obstruction from an intraoral ranula. This rare case highlights the need for a well considered contingency plan when surgery is required for a neonatal airway at risk.

Generalized dysplasia epiphysealis hemimelica with contralateral sacro-iliac joint involvement

International Nuclear Information System (INIS)

Karam, Adib R.; Birjawi, Ghina A.; Khoury, Nabil J.; Saghieh, Said; Tawil, Ayman

2008-01-01

Dysplasia epiphysealis hemimelica (or Trevor's disease) is a rare developmental bone dysplasia characterized by benign osteocartilaginous overgrowth involving one or multiple epiphyses, usually of a single lower extremity. It is classified as localized form, classical form (most common), and generalized form. In this report we describe a case of generalized form of dysplasia epiphysealis hemimelica with involvement of the contralateral sacroiliac joint, which is an extremely rare presentation. (orig.)

Generalized dysplasia epiphysealis hemimelica with contralateral sacro-iliac joint involvement

Energy Technology Data Exchange (ETDEWEB)

Karam, Adib R.; Birjawi, Ghina A.; Khoury, Nabil J. [American University of Beirut Medical Center, Department of Diagnostic Radiology, Beirut (Lebanon); Saghieh, Said [American University of Beirut Medical Center, Department of Orthopedic Surgery, Beirut (Lebanon); Tawil, Ayman [American University of Beirut Medical Center, Department of Pathology, Beirut (Lebanon)

2008-12-15

Dysplasia epiphysealis hemimelica (or Trevor's disease) is a rare developmental bone dysplasia characterized by benign osteocartilaginous overgrowth involving one or multiple epiphyses, usually of a single lower extremity. It is classified as localized form, classical form (most common), and generalized form. In this report we describe a case of generalized form of dysplasia epiphysealis hemimelica with involvement of the contralateral sacroiliac joint, which is an extremely rare presentation. (orig.)

Facilitated beam-walking recovery during acute phase by kynurenic acid treatment in a rat model of photochemically induced thrombosis causing focal cerebral ischemia.

Science.gov (United States)

Abo, Masahiro; Yamauchi, Hideki; Suzuki, Masahiko; Sakuma, Mio; Urashima, Mitsuyoshi

We previously demonstrated the presence of activated areas in the non-injured contralateral sensorimotor cortex in addition to the ipsilateral sensorimotor cortex of the area surrounding a brain infarction, using a rat model of focal photochemically induced thrombosis (PIT) and functional magnetic resonance imaging. Using this model, we next applied gene expression profiling to screen key molecules upregulated in the activated area. RNA was extracted from the ipsilateral and contralateral sensorimotor cortex to the focal brain infarction and from the sham controlled cortex, and hybridized to gene-expression profiling arrays containing 1,322 neurology-related genes. Results showed that glycine receptors were upregulated in both the ipsilateral and contralateral cortex to the focal ischemic lesion. To prove the preclinical significance of upregulated glycine receptors, kynurenic acid, an endogenous antagonist to glycine receptors on neuronal cells, was administered intrathecally. As a result, the kynurenic acid significantly improved behavioral recovery within 10 days from paralysis induced by the focal PIT (p beam walking. These results suggest that intrathecal administration of a glycine receptor antagonist may facilitate behavioral recovery during the acute phase after brain infarction. Copyright (c) 2006 S. Karger AG, Basel.

The impact of top-down spatial attention on laterality and hemispheric asymmetry in the human parietal cortex.

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Jeong, Su Keun; Xu, Yaoda

2016-08-01

The human parietal cortex exhibits a preference to contralaterally presented visual stimuli (i.e., laterality) as well as an asymmetry between the two hemispheres with the left parietal cortex showing greater laterality than the right. Using visual short-term memory and perceptual tasks and varying target location predictability, this study examined whether hemispheric laterality and asymmetry are fixed characteristics of the human parietal cortex or whether they are dynamic and modulated by the deployment of top-down attention to the target present hemifield. Two parietal regions were examined here that have previously been shown to be involved in visual object individuation and identification and are located in the inferior and superior intraparietal sulcus (IPS), respectively. Across three experiments, significant laterality was found in both parietal regions regardless of attentional modulation with laterality being greater in the inferior than superior IPS, consistent with their roles in object individuation and identification, respectively. Although the deployment of top-down attention had no effect on the superior IPS, it significantly increased laterality in the inferior IPS. The deployment of top-down spatial attention can thus amplify the strength of laterality in the inferior IPS. Hemispheric asymmetry, on the other hand, was absent in both brain regions and only emerged in the inferior but not the superior IPS with the deployment of top-down attention. Interestingly, the strength of hemispheric asymmetry significantly correlated with the strength of laterality in the inferior IPS. Hemispheric asymmetry thus seems to only emerge when there is a sufficient amount of laterality present in a brain region.

Visual object agnosia is associated with a breakdown of object-selective responses in the lateral occipital cortex.

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Ptak, Radek; Lazeyras, François; Di Pietro, Marie; Schnider, Armin; Simon, Stéphane R

2014-07-01

Patients with visual object agnosia fail to recognize the identity of visually presented objects despite preserved semantic knowledge. Object agnosia may result from damage to visual cortex lying close to or overlapping with the lateral occipital complex (LOC), a brain region that exhibits selectivity to the shape of visually presented objects. Despite this anatomical overlap the relationship between shape processing in the LOC and shape representations in object agnosia is unknown. We studied a patient with object agnosia following isolated damage to the left occipito-temporal cortex overlapping with the LOC. The patient showed intact processing of object structure, yet often made identification errors that were mainly based on the global visual similarity between objects. Using functional Magnetic Resonance Imaging (fMRI) we found that the damaged as well as the contralateral, structurally intact right LOC failed to show any object-selective fMRI activity, though the latter retained selectivity for faces. Thus, unilateral damage to the left LOC led to a bilateral breakdown of neural responses to a specific stimulus class (objects and artefacts) while preserving the response to a different stimulus class (faces). These findings indicate that representations of structure necessary for the identification of objects crucially rely on bilateral, distributed coding of shape features. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effects of rearranged vision on event-related lateralizations of the EEG during pointing.

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Berndt, Isabelle; Franz, Volker H; Bülthoff, Heinrich H; Gotz, Karl G; Wascher, Edmund

2005-01-01

We used event-related lateralizations of the EEG (ERLs) and reversed vision to study visuomotor processing with conflicting proprioceptive and visual information during pointing. Reversed vision decreased arm-related lateralization, probably reflecting the simultaneous activity of left and right arm specific neurons: neurons in the hemisphere contralateral to the observed action were probably activated by visual feedback, neurons in the hemisphere contralateral to the response side by the somatomotor feedback. Lateralization related to the target in parietal cortex increased, indicating that visual to motor transformation in parietal cortex required additional time and resources with reversed vision. A short period of adaptation to an additional lateral displacement of the visual field increased arm-contralateral activity in parietal cortex during the movement. This is in agreement with the, which showed that adaptation to a lateral displacement of the visual field is reflected in increased parietal involvement during pointing.

Spatial Frequency Selectivity Is Impaired in Dopamine D2 Receptor Knockout Mice

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Souza, Bruno Oliveira Ferreira; Abou Rjeili, Mira; Quintana, Clémentine; Beaulieu, Jean M.; Casanova, Christian

2018-01-01

Dopamine is a neurotransmitter implicated in several brain functions, including vision. In the present study, we investigated the impacts of the lack of D2 dopamine receptors on the structure and function of the primary visual cortex (V1) of D2-KO mice using optical imaging of intrinsic signals. Retinotopic maps were generated in order to measure anatomo-functional parameters such as V1 shape, cortical magnification factor, scatter, and ocular dominance. Contrast sensitivity and spatial frequency selectivity (SF) functions were computed from responses to drifting gratings. When compared to control mice, none of the parameters of the retinotopic maps were affected by D2 receptor loss of function. While the contrast sensitivity function of D2-KO mice did not differ from their wild-type counterparts, SF selectivity function was significantly affected as the optimal SF and the high cut-off frequency (p D2-KO than in WT mice. These findings show that the lack of function of D2 dopamine receptors had no influence on cortical structure whereas it had a significant impact on the spatial frequency selectivity and high cut-off. Taken together, our results suggest that D2 receptors play a specific role on the processing of spatial features in early visual cortex while they do not seem to participate in its development. PMID:29379422

Functional imaging of the sensorimotor cortex using an ultra-fast MR imaging method

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Tsunoda, Akira; Nakajima, Yasoichi; Sato, Kiyoshi; Katayama, Jin; Machida, Yoshio; Nozaki, Seiji; Makita, Jun-ichi.

1996-01-01

The aim of this study was to assess changes in brain activity during a motor task and variable sensory stimulation using echo planar imaging, which represents the fastest clinically useful imaging technique available. The subjects of this study were 11 healthy volunteers, 4 males and 11 females, with an average of 26.4 years. The subjects were instructed to tap the fingers of one hand as the motor task. Compressed air was applied 5 times a second as 'simple' sensory stimulation. Simple figures were drawn on the subjects palm as 'complex' sensory stimulation. In all cases, functional imaging was performed by T 2 * -weighted echo planar imaging (TE=53 msec, TR=3000 msec, flip angle=90 degrees, matrix 64 x 64, FOV=205 mm, slice thickness=8 mm) alternately at rest and during the task (intervals: 30 sec). A total of 60 images was collected in 3 minutes. Images obtained by subtracting images at rest and during the task were analyzed. Almost all subjects showed a transient signal increase in the contralateral paracentral region during simple sensory stimulation. Continuous signal increases in the contra- and/or ipsi-lateral para-central region were observed durirg complex sensory stimulation. Some exhibited signal increases in the parietal or frontal association cortex, but they disappeared when subject's attention was distracted during stimulation. All subjects displayed signal increases in the contralateral para-central region during the motor task. Some of them exhibited signal increases in the medial frontal area (supplementary motor area) and ipsilateral para-central region. These results suggest that the signal increases of functional MRI reflect not only simple reactions to stimulation but higher cerebral function as well. (J.P.N.)

[Neuroanatomy of Frontal Association Cortex].

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Takada, Masahiko

2016-11-01

The frontal association cortex is composed of the prefrontal cortex and the motor-related areas except the primary motor cortex (i.e., the so-called higher motor areas), and is well-developed in primates, including humans. The prefrontal cortex receives and integrates large bits of diverse information from the parietal, temporal, and occipital association cortical areas (termed the posterior association cortex), and paralimbic association cortical areas. This information is then transmitted to the primary motor cortex via multiple motor-related areas. Given these facts, it is likely that the prefrontal cortex exerts executive functions for behavioral control. The functional input pathways from the posterior and paralimbic association cortical areas to the prefrontal cortex are classified primarily into six groups. Cognitive signals derived from the prefrontal cortex are conveyed to the rostral motor-related areas to transform them into motor signals, which finally enter the primary motor cortex via the caudal motor-related areas. Furthermore, it has been shown that, similar to the primary motor cortex, areas of the frontal association cortex form individual networks (known as "loop circuits") with the basal ganglia and cerebellum via the thalamus, and hence are extensively involved in the expression and control of behavioral actions.

Combined Ipsilateral Oculomotor Nerve Palsy and Contralateral Downbeat Nystagmus in a Case of Cerebral Infarction

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Kosuke Matsuzono

2014-04-01

Full Text Available We report a patient with acute cerebral infarction of the left paramedian thalamus, upper mesencephalon and cerebellum who exhibited ipsilateral oculomotor nerve palsy and contralateral downbeat nystagmus. The site of the infarction was considered to be the paramedian thalamopeduncular and cerebellar regions, which are supplied by the superior cerebellar artery containing direct perforating branches or both the superior cerebellar artery and the superior mesencephalic and posterior thalamosubthalamic arteries. Contralateral and monocular downbeat nystagmus is very rare. Our case suggests that the present downbeat nystagmus was due to dysfunction of cerebellar-modulated crossed oculovestibular fibers of the superior cerebellar peduncle or bilateral downbeat nystagmus with one-sided oculomotor nerve palsy.

Electrocorticographic activity over sensorimotor cortex and motor function in awake behaving rats.

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Boulay, Chadwick B; Chen, Xiang Yang; Wolpaw, Jonathan R

2015-04-01

Sensorimotor cortex exerts both short-term and long-term control over the spinal reflex pathways that serve motor behaviors. Better understanding of this control could offer new possibilities for restoring function after central nervous system trauma or disease. We examined the impact of ongoing sensorimotor cortex (SMC) activity on the largely monosynaptic pathway of the H-reflex, the electrical analog of the spinal stretch reflex. In 41 awake adult rats, we measured soleus electromyographic (EMG) activity, the soleus H-reflex, and electrocorticographic activity over the contralateral SMC while rats were producing steady-state soleus EMG activity. Principal component analysis of electrocorticographic frequency spectra before H-reflex elicitation consistently revealed three frequency bands: μβ (5-30 Hz), low γ (γ1; 40-85 Hz), and high γ (γ2; 100-200 Hz). Ongoing (i.e., background) soleus EMG amplitude correlated negatively with μβ power and positively with γ1 power. In contrast, H-reflex size correlated positively with μβ power and negatively with γ1 power, but only when background soleus EMG amplitude was included in the linear model. These results support the hypothesis that increased SMC activation (indicated by decrease in μβ power and/or increase in γ1 power) simultaneously potentiates the H-reflex by exciting spinal motoneurons and suppresses it by decreasing the efficacy of the afferent input. They may help guide the development of new rehabilitation methods and of brain-computer interfaces that use SMC activity as a substitute for lost or impaired motor outputs. Copyright © 2015 the American Physiological Society.

Contralateral Occlusion Test: The effect of external ear canal occlusion on hearing thresholds.

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Reis, Luis Roque; Fernandes, Paulo; Escada, Pedro

Bedside testing with tuning forks may decrease turnaround time and improve decision making for a quick qualitative assessment of hearing loss. The purpose of this study was to quantify the effects of ear canal occlusion on hearing, in order to decide which tuning fork frequency is more appropriate to use for quantifying hearing loss with the Contralateral Occlusion Test. Twenty normal-hearing adults (forty ears) underwent sound field pure tone audiometry with and without ear canal occlusion. Each ear was tested with the standard frequencies. The contralateral ear was suppressed with by masking. Ear occlusion was performed by two examiners. Participants aged between 21 and 30 years (25.6±3.03 years) showed an increase in hearing thresholds with increasing frequencies from 19.94dB (250Hz) to 39.25dB (2000Hz). The threshold difference between occluded and unoccluded conditions was statistically significant and increased from 10.69dB (250Hz) to 32.12dB (2000Hz). There were no statistically significant differences according to gender or between the examiners. The occlusion effect increased the hearing thresholds and became more evident with higher frequencies. The occlusion method as performed demonstrated reproducibility. In the Contralateral Occlusion Test, 256Hz or 512Hz tuning forks should be used for diagnosis of mild hearing loss, and a 2048Hz tuning fork should be used for moderate hearing loss. Copyright © 2017 Elsevier España, S.L.U. and Sociedad Española de Otorrinolaringología y Cirugía de Cabeza y Cuello. All rights reserved.

Cellular Mechanisms Underlying Behavioral State-Dependent Bidirectional Modulation of Motor Cortex Output

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Julia Schiemann

2015-05-01

Full Text Available Neuronal activity in primary motor cortex (M1 correlates with behavioral state, but the cellular mechanisms underpinning behavioral state-dependent modulation of M1 output remain largely unresolved. Here, we performed in vivo patch-clamp recordings from layer 5B (L5B pyramidal neurons in awake mice during quiet wakefulness and self-paced, voluntary movement. We show that L5B output neurons display bidirectional (i.e., enhanced or suppressed firing rate changes during movement, mediated via two opposing subthreshold mechanisms: (1 a global decrease in membrane potential variability that reduced L5B firing rates (L5Bsuppressed neurons, and (2 a coincident noradrenaline-mediated increase in excitatory drive to a subpopulation of L5B neurons (L5Benhanced neurons that elevated firing rates. Blocking noradrenergic receptors in forelimb M1 abolished the bidirectional modulation of M1 output during movement and selectively impaired contralateral forelimb motor coordination. Together, our results provide a mechanism for how noradrenergic neuromodulation and network-driven input changes bidirectionally modulate M1 output during motor behavior.

Differentiation of Brain Tumor Recurrence from Post-Radiotherapy Necrosis with 11C-Methionine PET: Visual Assessment versus Quantitative Assessment.

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Ryogo Minamimoto

Full Text Available The aim of this multi-center study was to assess the diagnostic capability of visual assessment in L-methyl-11C-methionine positron emission tomography (MET-PET for differentiating a recurrent brain tumor from radiation-induced necrosis after radiotherapy, and to compare it to the accuracy of quantitative analysis.A total of 73 brain lesions (glioma: 31, brain metastasis: 42 in 70 patients who underwent MET-PET were included in this study. Visual analysis was performed by comparison of MET uptake in the brain lesion with MET uptake in one of four regions (around the lesion, contralateral frontal lobe, contralateral area, and contralateral cerebellar cortex. The concordance rate and logistic regression analysis were used to evaluate the diagnostic ability of visual assessment. Receiver-operating characteristic curve analysis was used to compare visual assessment with quantitative assessment based on the lesion-to-normal (L/N ratio of MET uptake.Interobserver and intraobserver κ-values were highest at 0.657 and 0.714, respectively, when assessing MET uptake in the lesion compared to that in the contralateral cerebellar cortex. Logistic regression analysis showed that assessing MET uptake in the contralateral cerebellar cortex with brain metastasis was significantly related to the final result. The highest area under the receiver-operating characteristic curve (AUC with visual assessment for brain metastasis was 0.85, showing no statistically significant difference with L/Nmax of the contralateral brain (AUC = 0.89 or with L/Nmean of the contralateral cerebellar cortex (AUC = 0.89, which were the areas that were the highest in the quantitative assessment. For evaluation of gliomas, no specific candidate was confirmed among the four areas used in visual assessment, and no significant difference was seen between visual assessment and quantitative assessment.The visual assessment showed no significant difference from quantitative assessment of MET

Whisker motor cortex reorganization after superior colliculus output suppression in adult rats.

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Veronesi, Carlo; Maggiolini, Emma; Franchi, Gianfranco

2013-10-01

The effect of unilateral superior colliculus (SC) output suppression on the ipsilateral whisker motor cortex (WMC) was studied at different time points after tetrodotoxin and quinolinic acid injections, in adult rats. The WMC output was assessed by mapping the movement evoked by intracortical microstimulation (ICMS) and by recording the ICMS-evoked electromyographic (EMG) responses from contralateral whisker muscles. At 1 h after SC injections, the WMC showed: (i) a strong decrease in contralateral whisker sites, (ii) a strong increase in ipsilateral whisker sites and in ineffective sites, and (iii) a strong increase in threshold current values. At 6 h after injections, the WMC size had shrunk to 60% of the control value and forelimb representation had expanded into the lateral part of the normal WMC. Thereafter, the size of the WMC recovered, returning to nearly normal 12 h later (94% of control) and persisted unchanged over time (1-3 weeks). The ICMS-evoked EMG response area decreased at 1 h after SC lesion and had recovered its baseline value 12 h later. Conversely, the latency of ICMS-evoked EMG responses had increased by 1 h and continued to increase for as long as 3 weeks following the lesion. These findings provide physiological evidence that SC output suppression persistently withdrew the direct excitatory drive from whisker motoneurons and induced changes in the WMC. We suggest that the changes in the WMC are a form of reversible short-term reorganization that is induced by SC lesion. The persistent latency increase in the ICMS-evoked EMG response suggested that the recovery of basic WMC excitability did not take place with the recovery of normal explorative behaviour. © 2013 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Is NAA reduction in normal contralateral cerebral tissue in stroke patients dependent on underlying risk factors?

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Walker, P M; Ben Salem, D; Giroud, M; Brunotte, F

2006-05-01

This retrospective study investigated the dependence of N-acetyl aspartate (NAA) ratios on risk factors for cerebral vasculopathy such as sex, age, hypertension, diabetes mellitus, carotid stenosis, and dyslipidaemia, which may have affected brain vessels and induced metabolic brain abnormalities prior to stroke. We hypothesise that in stroke patients metabolic alterations in the apparently normal contralateral brain are dependent on the presence or not of such risk factors. Fifty nine patients (31 male, 28 female: 58.8+/-16.1 years old) with cortical middle cerebral artery (MCA) territory infarction were included. Long echo time chemical shift imaging spectroscopy was carried out on a Siemens 1.5 T Magnetom Vision scanner using a multi-voxel PRESS technique. Metabolite ratios (NAA/choline, NAA/creatine, lactate/choline, etc) were studied using uni- and multivariate analyses with respect to common risk factors. The influence of age, stroke lesion size, and time since stroke was studied using a linear regression approach. Age, sex, and hypertension all appeared to individually influence metabolite ratios, although only hypertension was significant after multivariate analysis. In both basal ganglia and periventricular white matter regions in apparently normal contralateral brain, the NAA/choline ratio was significantly lower in hypertensive (1.37+/-0.16 and 1.50+/-0.19, respectively) than in normotensive patients (1.72+/-0.19 and 1.85+/-0.15, respectively). Regarding MCA infarction, contralateral tissue remote from the lesion behaves abnormally in the presence of hypertension, the NAA ratios in hypertensive patients being significantly lower. These data suggest that hypertension may compromise the use of contralateral tissue data as a reference for comparison with ischaemic tissue.

Endoscopic contralateral transmaxillary approach for pterygoid process osteotomy in total maxillectomy: A technical case report.

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Hanazawa, Toyoyuki; Yamasaki, Kazuki; Chazono, Hideaki; Okamoto, Yoshitaka

2018-06-01

An approach for total maxillectomy with endoscopic transection of the pterygoid process via the contralateral maxillary sinus is described. In total maxillectomy, the resection of the pterygoid process of the sphenoid is a key step for successful resection. However, a conventional craniofacial approach requires extensive incision in the face, elevation of the lateral cheek flap. Even after elevation of the lateral cheek flap, visualization of this region is not good. An endoscopic approach through the contralateral maxillary sinus improved visualization of the pterygoid process, and osteotomy using a diamond-drilling bar was successfully performed. This technique has the potential to widen the indication for total maxillectomy in malignant neoplasms of the maxillary sinus. Copyright © 2017 Elsevier B.V. All rights reserved.

Predictors for contralateral prophylactic mastectomy in breast cancer patients

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Fu, Yun; Zhuang, Zhigang; Dewing, Michelle; Apple, Sophia; Chang, Helena

2015-01-01

Background: In recent years, radical breast cancer surgery has been largely replaced by breast conservation treatment, due to early diagnosis and more effective adjuvant treatment. While breast conservation is mostly preferred, the trend of bilateral mastectomy has risen in the United States. The aim of this study is to determine factors influencing patients’ choice for having contralateral prophylactic mastectomy (CPM). Methods: This is a retrospective study of 373 patients diagnosed with primary invasive breast cancer who were treated by bilateral or unilateral mastectomy (BM or UM) at the Revlon/UCLA Breast Center between Jan. 2002 and Dec. 2010. In the BM group, only those with unilateral breast cancer who chose CPM were included in the analysis. Results: When compared with the UM group, the following factors were found to be associated with BM: younger age, pre-menopausal, a family history of breast/ovarian cancer, BRCA mutation, more breast biopsies, history of breast augmentation, having MRI study within 6 months before the surgery, more likely to have reconstruction and sentinel lymph node biopsy (SLNB) and fewer had neoadjuvant/adjuvant chemotherapy/radiation. When patients with bilateral breast cancer were excluded, multivariate logistic regression analysis indicated younger patients with negative nodes, SLNB as the only nodal surgery and positive family history were significant factors predicting CPM and immediate reconstruction using tissue expanders or implants. Conclusion: Younger age, lower TN stage, requiring only SLNB and high risk family history predict contralateral prophylactic mastectomy. Tissue expander/implant-based reconstructions were more frequently chosen by patients with BM. PMID:26097557

Role of the right inferior parietal cortex in auditory selective attention: An rTMS study.

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Bareham, Corinne A; Georgieva, Stanimira D; Kamke, Marc R; Lloyd, David; Bekinschtein, Tristan A; Mattingley, Jason B

2018-02-01

Selective attention is the process of directing limited capacity resources to behaviourally relevant stimuli while ignoring competing stimuli that are currently irrelevant. Studies in healthy human participants and in individuals with focal brain lesions have suggested that the right parietal cortex is crucial for resolving competition for attention. Following right-hemisphere damage, for example, patients may have difficulty reporting a brief, left-sided stimulus if it occurs with a competitor on the right, even though the same left stimulus is reported normally when it occurs alone. Such "extinction" of contralesional stimuli has been documented for all the major sense modalities, but it remains unclear whether its occurrence reflects involvement of one or more specific subregions of the temporo-parietal cortex. Here we employed repetitive transcranial magnetic stimulation (rTMS) over the right hemisphere to examine the effect of disruption of two candidate regions - the supramarginal gyrus (SMG) and the superior temporal gyrus (STG) - on auditory selective attention. Eighteen neurologically normal, right-handed participants performed an auditory task, in which they had to detect target digits presented within simultaneous dichotic streams of spoken distractor letters in the left and right channels, both before and after 20 min of 1 Hz rTMS over the SMG, STG or a somatosensory control site (S1). Across blocks, participants were asked to report on auditory streams in the left, right, or both channels, which yielded focused and divided attention conditions. Performance was unchanged for the two focused attention conditions, regardless of stimulation site, but was selectively impaired for contralateral left-sided targets in the divided attention condition following stimulation of the right SMG, but not the STG or S1. Our findings suggest a causal role for the right inferior parietal cortex in auditory selective attention. Copyright © 2017 Elsevier Ltd. All rights

Benefits of awake uniportal pulmonary resection in a patient with a previous contralateral lobectomy.

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Galvez, Carlos; Navarro-Martinez, Jose; Bolufer, Sergio; Lirio, Francisco; Mafe, Juan Jose; Rivera, Maria Jesus; Roca, Joaquin; Baschwitz, Benno

2014-09-01

Surgical resection of a contralateral recurrence of non-small cell lung cancer (NSCLC) is indicated in patients without evidence of disseminated disease and considered functionally operable. General anesthesia and double-lumen intubation involves one lobe ventilation in a patient treated with a previous lobectomy, thus increasing the risks of ventilator-induced injuries and the morbidity. Awake procedures facilitate the surgery decreasing the anesthetic and surgical times, keeping the diaphragm motion and diminishing the ventilator-induced injuries into the remaining contralateral lobe. We present a 43-year-old woman with a previous left-lower lobectomy for a 3.1-cm mucinous adenocarcinoma 15 months before without nodal involvement, who presents a right-lower lobe 8-mm cavitated nodule, with evident radiological growth and fine-needle aspiration concordant with mucinous adenocarcinoma. We suggest an awake procedure with locoregional epidural anesthesia.

Evidence for proteolytic cleavage of brevican by the ADAMTSs in the dentate gyrus after excitotoxic lesion of the mouse entorhinal cortex

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Gottschall Paul E

2005-08-01

Full Text Available Abstract Background Brevican is a member of the lectican family of aggregating extracellular matrix (ECM proteoglycans that bear chondroitin sulfate (CS chains. It is highly expressed in the central nervous system (CNS and is thought to stabilize synapses and inhibit neural plasticity and as such, neuritic or synaptic remodeling would be less likely to occur in regions with intact and abundant, lectican-containing, ECM complexes. Neural plasticity may occur more readily when these ECM complexes are broken down by endogenous proteases, the ADAMTSs (adisintegrin and metalloproteinase with thrombospondin motifs, that selectively cleave the lecticans. The purpose of these experiments was to determine whether the production of brevican or the ADAMTS-cleaved fragments of brevican were altered after deafferentation and reinnervation of the dentate gyrus via entorhinal cortex lesion (ECL. Results In the C57Bl6J mouse, synaptic density in the molecular layer of the dentate gyrus, as measured by synaptophysin levels in ELISA, was significantly attenuated 2 days (nearly 50% of contralateral and 7 days after lesion and returned to levels not different from the contralateral region at 30 days. Immunoreactive brevican in immunoblot was elevated 2 days after lesion, whereas there was a significant increase in the proteolytic product at 7, but not 30 days post-lesion. ADAMTS activity, estimated using the ratio of the specific ADAMTS-derived brevican fragment and intact brevican levels was increased at 7 days, but was not different from the contralateral side at 2 or 30 days after deafferentation. Conclusion These findings indicate that ADAMTS activity in the dentate outer molecular layer (OML is elevated during the initial synaptic reinnervation period (7 days after lesion. Therefore, proteolytic processing of brevican appears to be a significant extracellular event in the remodeling of the dentate after EC lesion, and may modulate the process of sprouting and

Single-Lung Ventilation with Contralateral Lung Deflation

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Dallan, Luís Alberto O.; Lisboa, Luiz Augusto F.; Platania, Fernando; Oliveira, Sérgio A.; Stolf, Noedir A.

2007-01-01

There are many new alternative methods of minimally invasive myocardial revascularization that can be applied in selected patients who have multivessel coronary artery disease. However, these techniques often require new and expensive equipment. Most multivessel myocardial revascularization is performed via median sternotomy and involves the use of a conventional endotracheal tube. Both lungs are ventilated, and frequently the left pleural cavity is opened. In contrast, single-lung deflation naturally moves the mediastinum within the thorax toward the collapsed lung, without the need to open the pleural cavities. Herein, we describe a simple alternative procedure that facilitates off-pump multivessel coronary artery bypass grafting via complete median sternotomy: single-lung ventilation with contralateral lung deflation. This technique better exposes the more distal right and circumflex coronary artery branches with or without the opening of the pleural cavities. PMID:17622364

Increased GABA-A receptor binding and reduced connectivity at the motor cortex in children with hemiplegic cerebral palsy: a multimodal investigation using 18F-fluoroflumazenil PET, immunohistochemistry, and MR imaging.

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Park, Hae-Jeong; Kim, Chul Hoon; Park, Eun Sook; Park, Bumhee; Oh, So Ra; Oh, Maeng-Keun; Park, Chang Il; Lee, Jong Doo

2013-08-01

γ-aminobutyric acid (GABA)-A receptor-mediated neural transmission is important to promote practice-dependent plasticity after brain injury. This study investigated alterations in GABA-A receptor binding and functional and anatomic connectivity within the motor cortex in children with cerebral palsy (CP). We conducted (18)F-fluoroflumazenil PET on children with hemiplegic CP to investigate whether in vivo GABA-A receptor binding is altered in the ipsilateral or contralateral hemisphere of the lesion site. To evaluate changes in the GABA-A receptor subunit after prenatal brain injury, we performed GABA-A receptor immunohistochemistry using rat pups with a diffuse hypoxic ischemic insult. We also performed diffusion tensor MR imaging and resting-state functional MR imaging on the same children with hemiplegic CP to investigate alterations in anatomic and functional connectivity at the motor cortex with increased GABA-A receptor binding. In children with hemiplegic CP, the (18)F-fluoroflumazenil binding potential was increased within the ipsilateral motor cortex. GABA-A receptors with the α1 subunit were highly expressed exclusively within cortical layers III, IV, and VI of the motor cortex in rat pups. The motor cortex with increased GABA-A receptor binding in children with hemiplegic CP had reduced thalamocortical and corticocortical connectivity, which might be linked to increased GABA-A receptor distribution in cortical layers in rats. Increased expression of the GABA-A receptor α1 subunit within the ipsilateral motor cortex may be an important adaptive mechanism after prenatal brain injury in children with CP but may be associated with improper functional connectivity after birth and have adverse effects on the development of motor plasticity.

[Glomerular changes in the contralateral kidney in the rat with experimental hydronephrosis].

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Castillo Bernabéu, R; Gázquez Ortiz, A; Bonillo Morales, A; Sierra Planas, M A; Ocaña Losa, J M; Romanos Lezcano, A

1985-10-31

We have studied under optic and electronmicroscopes the alterations of glomeruli in contralateral kidneys of rats with experimental hydronephrosis. Forty-eight Wistar rats, divided into two groups (control and experimental) were used. They were sacrificed 3, 6, 9 and 12 days after ureteral obstruction. There was a slight hypertrophy of glomeruli and hiperplasia of other components accompanied by a increased development of podocytes.

Funtional MRI of cerebral motor cortex: comparison between 1.0 T and 1.5 T

International Nuclear Information System (INIS)

Jang, Hyun Jung; Yu, In Kyu; Song, In Chan; Han, Moon Hee; Lee, Heung Kyu; Chang, Kee Hyun

1997-01-01

To evaluate the feasibility of functional MR imaging(fMRI) with a 1.0 T scanner, fMRI of normal cerebral motor cortex at 1.0 T was compared with that at 1.5 T. FMRI of bilateral cerebral motor cortices (left, seven; right, six) was performed in seven healthy male volunteers aged 26-34 (mean 29) years,with BOLD contrast at both 1.0 T and 1.5 T units(Siemens MR scanners). Using both these systems,two-dimensional(2D) FLASH images were obtained with TR/TE of 90/56, flip angle of 40 deg, matrix size 128 * 128, slice thickness of 5mm, and FOV 23cm. A sequence consisting of five-image-off phase(rest phase) followed by five-image-on phase(activation with finger movement) was repeated four times without pause at a single plane. The same study was perfomed for the contralateral motor cortex in each volunteer. Using the z-test, activation images were obtained for the signal difference between on-and off-phases (p<0.05) and were then superimposed on 2D FLASH anatomic images at the same plane. Percentage changes of signal intensities(PCSIs) and numbers of activated pixels were compared, using the non-paramatric t-test, and periodicity of signal changes was compared, using the Mentel-Haenszel Chi-square test. Mean PCSIs at 1.5 T and 1.0 T in the left motor cortex were 3.13 ±1.20% and 1.43±0.56%, respectively(p=0.009),and in the right, 1.78±0.95% and 1.34±0.28%, respectively(p=0.32). The mean number of activated pixels at 1.5 T and 1.0 T in the left cortex was 21.14±10.67 and 19.86±11.36, respectively (p=0.83), and in the right, 22.5±6.47 and 16.8±8.47, respectively (p=0.22). At 1.5 T, periodicity of signal changes was seen in the left cortex in six of seven volunteers, and in the right cortex, in four of six. At 1.0 T, all showed periodicity (left:p=0.32;right:p=0.14). PCSIs in the dominant hemispheres were significantly higher at 1.5 T, but no other indicators showed significant differences between 1.0 T and 1.5 T. Acceptable fMRI can therefore be carried out with a 1

Surveillance mammography for detecting ipsilateral breast tumour recurrence and metachronous contralateral breast cancer: a systematic review

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Robertson, Clare; Boachie, Charles; Fraser, Cynthia; MacLennan, Graeme; Mowatt, Graham; Thomas, Ruth E. [University of Aberdeen, Health Services Research Unit, Aberdeen (United Kingdom); Ragupathy, Senthil Kumar Arcot [NHS Grampian, Radiology Department, Aberdeen Royal Infirmary, Aberdeen (United Kingdom); Heys, Steve D. [University of Aberdeen and Aberdeen Royal Infirmary, NHS Grampian, Division of Applied Medicine, School of Medicine and Dentistry, Aberdeen (United Kingdom); Gilbert, Fiona J. [University of Aberdeen and Aberdeen Royal Infirmary, NHS Grampian, Aberdeen Biomedical Imaging Centre, Aberdeen (United Kingdom)

2011-12-15

To determine the diagnostic accuracy of surveillance mammography for detecting ipsilateral breast tumour recurrence and metachronous contralateral breast cancer in women previously treated for primary breast cancer. A systematic review of surveillance mammography compared with ultrasound, magnetic resonance imaging (MRI), specialist-led clinical examination or unstructured primary care follow-up, using histopathological assessment for test positives and follow-up for test negatives as the reference standard. Nine studies met our inclusion criteria. Variations in study comparisons precluded meta-analysis. For routine ipsilateral breast tumour detection, surveillance mammography sensitivity ranged from 64-67% and specificity ranged from 85-97%. For MRI, sensitivity ranged from 86-100% and specificity was 93%. For non-routine ipsilateral breast tumour detection, sensitivity and specificity for surveillance mammography ranged from 50-83% and 57-75% and for MRI 93-100% and 88-96%. For routine metachronous contralateral breast cancer detection, one study reported sensitivity of 67% and specificity of 50% for both surveillance mammography and MRI. Although mammography is associated with high sensitivity and specificity, MRI is the most accurate test for detecting ipsilateral breast tumour recurrence and metachronous contralateral breast cancer in women previously treated for primary breast cancer. Results should be interpreted with caution because of the limited evidence base. (orig.)

Improving visual perception through neurofeedback

Science.gov (United States)

Scharnowski, Frank; Hutton, Chloe; Josephs, Oliver; Weiskopf, Nikolaus; Rees, Geraint

2012-01-01

Perception depends on the interplay of ongoing spontaneous activity and stimulus-evoked activity in sensory cortices. This raises the possibility that training ongoing spontaneous activity alone might be sufficient for enhancing perceptual sensitivity. To test this, we trained human participants to control ongoing spontaneous activity in circumscribed regions of retinotopic visual cortex using real-time functional MRI based neurofeedback. After training, we tested participants using a new and previously untrained visual detection task that was presented at the visual field location corresponding to the trained region of visual cortex. Perceptual sensitivity was significantly enhanced only when participants who had previously learned control over ongoing activity were now exercising control, and only for that region of visual cortex. Our new approach allows us to non-invasively and non-pharmacologically manipulate regionally specific brain activity, and thus provide ‘brain training’ to deliver particular perceptual enhancements. PMID:23223302

CE-Magnetic Resonance mammography for the evaluation of the contralateral breast in patients with diagnosed breast cancer

International Nuclear Information System (INIS)

Pediconi, Federica; Venditti, Fiammetta; Padula, Simona; Roselli, Antonella; Moriconi, Enrica; Catalano, Carlo; Passariello, Roberto; Giacomelli, Laura

2005-01-01

Purpose. To evaluate the role of contrast-enhanced Magnetic Resonance Mammography (MRM) in the evaluation of the contralateral breast in patients with recently diagnosed breast cancer. Materials and methods. Fifty patients with proved unilateral breast cancer, with a negative contralateral breast at physical examination, ultrasound and mammography, were studied with a 1.5 T magnet (Siemens, Vision Plus, Germany). A bilateral breast surface coil was used. Dynamic 3D Flash T1-weighted sequences were acquired in the axial plane before and 0, 2, 4, 6 and 8 minutes after the administration of 0.1 mmol/kg of Gd-BOPTA at a flow rate of 2 ml/s followed by 10 ml of saline. The level of suspicion was reported on a scale from 0 to 5 following the BI-RADS classification, based on lesion morphology and kinetic features. The results were compared with the histological findings after biopsy or surgery. Results. Fourteen out of 50 patients (28%) had contralateral lesions identified on MRM. Biopsy was performed in four of them for suspicious lesions (BI-RADS 4) while 10 patients underwent surgery because of highly suggestive malignant lesions (BI-RADS 5). Histology diagnosed three fibroadenomas, 5 ductal carcinoma in situ, 2 lobular carcinomas in situ, 3 invasive ductal carcinomas and 1 invasive lobular carcinoma. Contrast enhanced MRM yielded no false negative and three false positives. Conclusions. Our results demonstrate a very good accuracy of Magnetic Resonance Mammography in the detection of synchronous contralateral cancer in patients with newly diagnosed breast cancer. Therefore, contrast-enhanced MRM could be introduced to screen patients with proven breast cancer before they under-go surgery [it

Carotid endarterectomy in cervical block anesthesia in patients with occluded contralateral internal carotid artery

Directory of Open Access Journals (Sweden)

Ilijevski Nenad

2006-01-01

Full Text Available Introduction: The goal of modern carotid surgery is relief of symptoms, stroke prevention, improvement in quality of life, prevention of vascular dementia, and prolongation of lifetime. OBJECTIVE: The objective of this paper was to compare the outcome of carotid endarterectomy in cervical block vs. general anesthesia in patients with occluded contralateral internal carotid artery (ICA. METHOD: One hundred patients (76 male, 24 female, mean age 60.81 years with occluded contralateral ICA were operated from 1997-2000. Neurological symptomatology, deficiency and stroke incidence were preoperatively analyzed in two groups. Duplex-scanning, angiograms and CT-scan confirmed the diagnosis. Risk factors analysis included hypertension, diabetes, lipid metabolism disorders, smoking and history of CAD, CABG and PAOD. Morbidity and mortality were used to compare the outcome of surgery in two groups. RESULTS There was no difference of age, gender and symptomatology between the groups. Paresis, TIA and dysphasia were most frequent. 70%-90% of ICA stenosis was seen in the majority of patients. Hypertension and smoking were dominant risk factors in these two groups. Eversion carotid end arterectomy was the most frequent technique used. In three cases out of nine that were operated under cervical block, the neurological symptoms developed just after clamping, so the intra-luminal shunt was placed. Postoperative morbidity was 12% and mortality was 8%. Conclusion: There was no difference of preoperative parameters, surgical technique and outcome in these two groups. Without other intraoperative monitoring, cervical block anesthesia might be an option in patients with the occlusion of the contralateral ICA. However, prospective studies involving more patients are needed.

Stimulus uncertainty enhances long-term potentiation-like plasticity in human motor cortex.

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Sale, Martin V; Nydam, Abbey S; Mattingley, Jason B

2017-03-01

Plasticity can be induced in human cortex using paired associative stimulation (PAS), which repeatedly and predictably pairs a peripheral electrical stimulus with transcranial magnetic stimulation (TMS) to the contralateral motor region. Many studies have reported small or inconsistent effects of PAS. Given that uncertain stimuli can promote learning, the predictable nature of the stimulation in conventional PAS paradigms might serve to attenuate plasticity induction. Here, we introduced stimulus uncertainty into the PAS paradigm to investigate if it can boost plasticity induction. Across two experimental sessions, participants (n = 28) received a modified PAS paradigm consisting of a random combination of 90 paired stimuli and 90 unpaired (TMS-only) stimuli. Prior to each of these stimuli, participants also received an auditory cue which either reliably predicted whether the upcoming stimulus was paired or unpaired (no uncertainty condition) or did not predict the upcoming stimulus (maximum uncertainty condition). Motor evoked potentials (MEPs) evoked from abductor pollicis brevis (APB) muscle quantified cortical excitability before and after PAS. MEP amplitude increased significantly 15 min following PAS in the maximum uncertainty condition. There was no reliable change in MEP amplitude in the no uncertainty condition, nor between post-PAS MEP amplitudes across the two conditions. These results suggest that stimulus uncertainty may provide a novel means to enhance plasticity induction with the PAS paradigm in human motor cortex. To provide further support to the notion that stimulus uncertainty and prediction error promote plasticity, future studies should further explore the time course of these changes, and investigate what aspects of stimulus uncertainty are critical in boosting plasticity. Copyright © 2016 Elsevier Ltd. All rights reserved.

Influence of position and stimulation parameters on intracortical inhibition and facilitation in human tongue motor cortex

DEFF Research Database (Denmark)

Kothari, Mohit; Svensson, Peter; Nielsen, Jørgen Feldbæk

2014-01-01

Paired-pulse transcranial magnetic stimulation (ppTMS) can be used to assess short-interval intracortical inhibitory (SICI) and facilitatory (ICF) networks. Many methodological parameters may however influence the outcome. The aim of the study was to examine the influence of body positions (recline...... motor cortex and motor evoked potentials (MEPs) were recorded from contralateral tongue muscles. In study 1, single pulse and three ppTMS ISIs: 2, 10, 15 ms were applied 8 times each in three blocks (TS: 120%, 140% and 160% of resting motor threshold (rMT); CS: 80% of rMT) in two different body...... positions (recline and supine) randomly. In study 2, single pulse and four ppTMS ISIs: 2, 2.5, 3, 3.5 ms were applied 8 times each in randomized order in two blocks (CS: 70% and 80% of rMT; TS: 120% of rMT). There was a significant effect of body position (P=0.049), TS intensities (P

On the Relationship Between Musicianship and Contralateral Suppression of Transient-Evoked Otoacoustic Emissions.

Science.gov (United States)

Stuart, Andrew; Daughtrey, Emma R

2016-04-01

The medial olivocochlear (MOC) efferent reflex that modulates outer hair cell function has been shown to be more robust in musicians versus nonmusicians as evidenced in greater contralateral suppression of transient-evoked otoacoustic emissions (TEOAEs). All previous research comparing musical ability and MOC efferent strength has defined musicianship dichotomously (i.e., high-level music students or professional classical musicians versus nonmusicians). The objective of the study was to further explore contralateral suppression of TEOAEs among adults with a full spectrum of musicianship ranging from no history of musicianship to professional musicians. Musicianship was defined by both self-report and with an objective test to quantify individual differences in perceptual music skills. A single-factor between-subjects and correlational research designs were employed. Forty-five normal-hearing young adults participated. Participants completed a questionnaire concerning their music experience and completed the Brief Profile of Music Perception Skills (PROMS) to quantify perceptual musical skills across multiple musical domains (i.e., accent, melody, tempo, and tuning). TEOAEs were evaluated with 60 dB peak equivalent sound pressure level click stimuli with and without a contralateral 65 dB sound pressure level white noise suppressor. TEOAE suppression was expressed in two ways, absolute TEOAE suppression in dB and a normalized index of TEOAE suppression (i.e., percentage of suppression). Participants who considered themselves musicians scored significantly higher on all subscales and total Brief PROMS score (p 0.05). There were no statistically significant correlations or linear predictive relationships between subscale or total Brief PROMS scores with absolute and percentage of TEOAE suppression (p > 0.05). The findings do not support the notion of a graded enhancement of MOC efferent suppression among adults with varied degrees of musicianship from nonmusicians to

SU-F-T-536: Contra-Lateral Breast Study for Prone Versus Supine Patients

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Marrero, M; Joseph, K; Klein, E [Northwell Health, Lake Success, NY (United States)

2016-06-15

Purpose: There are several advantages to utilizing the prone technique for intact breast cancer patients. However, as the topography changes, accompanied by the influence of a supporting breast board and patient treatment couch, the question that arises is to whether there is a concern for contralateral breast dose for intact breast cancer patients being treated with this technique. Methods: An anthropomorphic phantom with breast mounds to duplicate intact breast cancer treatment was planned in prone and supine position. Two tangential beams were executed in the similar manner for as the radiotherapy planning system. For the prone setup, a breast dense foam board was used to support the phantom. A grid of 24 OSL nanodots was placed at 6cm, 4cm, and 2cm apart from the medial border for both prone and supine setups. The phantom was set up using megavoltage imaging and treated as per plan. Additional, a similar study was performed on a patient treated in prone position. Results: Overall, the contralateral breast dose was generally higher for prone setups at all locations especially when close to the medial border. The average mean dose was found to be 1.8%, 2.5% of the prescribed dose for supine respectively prone position. The average of the standard deviation is 1.04%, 1.38% for supine respectively prone position. As for patient treated in prone position average mean dose was found to be 1.165% of the prescribed dose and average of the standard deviation is 9.456%. Conclusion: There is minimal influence of scatter from the breast board. It appears that the volatility of the setup could lead to higher doses than expected from the planning system to the contralateral breast when the patient is in the prone position.

Functional MR imaging of the motor cortex in healthy volunteers and patients with brain tumours: qualitative and quantitative results

Energy Technology Data Exchange (ETDEWEB)

Fellner, C. [Friedrich-Alexander-Univ., Erlangen-Nuernberg (Germany). Inst. of Medical Physics]|[Friedrich-Alexander-Univ., Erlangen-Nuernberg (Germany). Dept. of Diagnostic Radiology; Schlaier, J.; Schwerdtner, J.; Brawanski, A. [Regensburg Univ. (Germany). Dept. of Radiology; Fellner, F. [Regensburg Univ. (Germany). Dept. of Neurosurgery]|[Oberoesterreichische Landesnervenklinik, Linz (Austria). Dept. of Neuroradiology; Held, P. [Friedrich-Alexander-Univ., Erlangen-Nuernberg (Germany). Dept. of Diagnostic Radiology; Blank, M.; Kalender, W.A. [Friedrich-Alexander-Univ., Erlangen-Nuernberg (Germany). Inst. of Medical Physics

1999-06-01

The purpose of this study was to compare functional magnetic resonance (MR) imaging of the motor cortex in healthy volunteers and patients with brain tumours. Functional MR imaging was performed in 14 healthy volunteers and 14 patients with tumours in or near the primary motor cortex with groups being matched for age, sex, and handedness. Functional images were acquired during motion of the right and left hand. Time courses of signal intensity within the contralateral, ipsilateral, and supplementary motor cortex as well as z-maps were calculated, their quality being assessed visually. Mean signal increase between activation and rest were evaluated within the contralateral, ipsilateral, and supplementary motor cortex, the activated area in those regions of interest was measured using z-maps. The quality of functional MR experiments was generally lower in patients than in volunteers. The quantitative results showed a trend towards increased ipsilateral activation in volunteers during left hand compared to right hand motion and in patients during motion of the affected compared to the non-affected hand. Considering quantitative and qualitative results, significantly increased ipsilateral activation was found in patients compared to healthy volunteers. In conclusion, functional MR imaging quality was significantly reduced in patient studies compared to healthy volunteers, even if influences of age, sex, and handedness were excluded. Increased ipsilateral activation was found in patients with brain tumours which can be interpreted by an improved connectivity between both hemispheres. (orig.) [Deutsch] Das Ziel der vorliegenden Studie war ein Vergleich der funktionellen MR-Bildgebung (fMRI: Functional magnetic resonance imaging) des Motorkortex bei gesunden Probanden und Patienten mit Hirntumor. Die funktionelle MR-Bildgebung wurde bei 14 gesunden Probanden und bei 14 Patienten mit einem Tumor im oder nahe des primaeren Motorkortex durchgefuehrt, wobei beide Kollektive

Increased growth rate of vestibular schwannoma after resection of contralateral tumor in neurofibromatosis type 2

Science.gov (United States)

Peyre, Matthieu; Goutagny, Stephane; Imbeaud, Sandrine; Bozorg-Grayeli, Alexis; Felce, Michele; Sterkers, Olivier; Kalamarides, Michel

2011-01-01

Surgical management of bilateral vestibular schwannomas (VS) in neurofibromatosis type 2 (NF2) is often difficult, especially when both tumors threaten the brainstem. When the largest tumor has been removed, the management of the contralateral VS may become puzzling. To give new insights into the growth pattern of these tumors and to determine the best time point for treatment (surgery or medical treatment), we studied radiological growth in 11 VS (11 patients with NF2) over a long period (mean duration, 7.6 years), before and after removal of the contralateral tumor while both were threatening the brainstem. We used a quantitative approach of the radiological velocity of diametric expansion (VDE) on consecutive magnetic resonance images. Before first surgery, growth patterns of both tumors were similar in 9 of 11 cases. After the first surgery, VDE of the remaining VS was significantly elevated, compared with the preoperative period (2.5 ± 2.2 vs 4.4 ± 3.4 mm/year; P = .01, by Wilcoxon test). Decrease in hearing function was associated with increased postoperative growth in 3 cases. Growth pattern of coexisting intracranial meningiomas was not modified by VS surgery on the first side. In conclusion, removal of a large VS in a patient with NF2 might induce an increase in the growth rate of the contralateral medium or large VS. This possibility should be integrated in NF2 patient management to adequately treat the second VS. PMID:21798887

Lateralization of cortical negative motor areas.

Science.gov (United States)

Borggraefe, Ingo; Catarino, Claudia B; Rémi, Jan; Vollmar, Christian; Peraud, Aurelia; Winkler, Peter A; Noachtar, Soheyl

2016-10-01

The lateral and mesial aspects of the central and frontal cortex were studied by direct electrical stimulation of the cortex in epilepsy surgery candidates in order to determine the localization of unilateral and bilateral negative motor responses. Results of electrical cortical stimulation were examined in epilepsy surgery candidates in whom invasive electrodes were implanted. The exact localization of subdural electrodes was defined by fusion of 3-dimensional reconstructed MRI and CT images in 13 patients and by analysis of plane skull X-rays and intraoperative visual localization of the electrodes in another 7 patients. Results of electrical stimulation of the cortex were evaluated in a total of 128 patients in whom invasive electrodes were implanted for planning resective epilepsy surgery. Twenty patients, in whom negative motor responses were obtained, were included in the study. Bilateral upper limb negative motor responses were more often elicited from stimulation of the mesial frontal cortex whereas stimulation of the lateral central cortex leads to contralateral upper limb negative motor responses (pfrontal gyrus whereas contralateral negative motor responses localized predominantly in the anterior part of the precentral gyrus (pgyrus and the mesial fronto-central cortex showing functional differences with regard to unilateral and bilateral upper limb representation. The lateral fronto-central negative motor area serves predominantly contralateral upper limb motor control whereas the mesial frontal negative motor area represents bilateral upper limb movement control. Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Sperm Concentration, Testicular Volume and Age Predict Risk of Carcinoma In Situ in Contralateral Testis of Men with Testicular Germ Cell Cancer

DEFF Research Database (Denmark)

Rud, Camilla Nymann; Daugaard, Gedske; Rajpert-De Meyts, Ewa

2013-01-01

We investigated whether semen quality or some easily attainable clinical parameters might be used to estimate the risk of contralateral carcinoma in situ in patients with unilateral testicular germ cell tumors.......We investigated whether semen quality or some easily attainable clinical parameters might be used to estimate the risk of contralateral carcinoma in situ in patients with unilateral testicular germ cell tumors....

Cooperation Not Competition: Bihemispheric tDCS and fMRI Show Role for Ipsilateral Hemisphere in Motor Learning.

Science.gov (United States)

Waters, Sheena; Wiestler, Tobias; Diedrichsen, Jörn

2017-08-02

What is the role of ipsilateral motor and premotor areas in motor learning? One view is that ipsilateral activity suppresses contralateral motor cortex and, accordingly, that inhibiting ipsilateral regions can improve motor learning. Alternatively, the ipsilateral motor cortex may play an active role in the control and/or learning of unilateral hand movements. We approached this question by applying double-blind bihemispheric transcranial direct current stimulation (tDCS) over both contralateral and ipsilateral motor cortex in a between-group design during 4 d of unimanual explicit sequence training in human participants. Independently of whether the anode was placed over contralateral or ipsilateral motor cortex, bihemispheric stimulation yielded substantial performance gains relative to unihemispheric or sham stimulation. This performance advantage appeared to be supported by plastic changes in both hemispheres. First, we found that behavioral advantages generalized strongly to the untrained hand, suggesting that tDCS strengthened effector-independent representations. Second, functional imaging during speed-matched execution of trained sequences conducted 48 h after training revealed sustained, polarity-independent increases in activity in both motor cortices relative to the sham group. These results suggest a cooperative rather than competitive interaction of the two motor cortices during skill learning and suggest that bihemispheric brain stimulation during unimanual skill learning may be beneficial because it harnesses plasticity in the ipsilateral hemisphere. SIGNIFICANCE STATEMENT Many neurorehabilitation approaches are based on the idea that is beneficial to boost excitability in the contralateral hemisphere while attenuating that of the ipsilateral cortex to reduce interhemispheric inhibition. We observed that bihemispheric transcranial direct current stimulation (tDCS) with the excitatory anode either over contralateral or ipsilateral motor cortex

Cerebral cortex modulation of pain

Institute of Scientific and Technical Information of China (English)

Yu-feng XIE; Fu-quan HUO; Jing-shi TANG

2009-01-01

Pain is a complex experience encompassing sensory-discriminative, affective-motivational and cognitiv e-emotional com-ponents mediated by different mechanisms. Contrary to the traditional view that the cerebral cortex is not involved in pain perception, an extensive cortical network associated with pain processing has been revealed using multiple methods over the past decades. This network consistently includes, at least, the anterior cingulate cortex, the agranular insular cortex, the primary (SⅠ) and secondary somatosensory (SⅡ) cortices, the ventrolateral orbital cortex and the motor cortex. These corti-cal structures constitute the medial and lateral pain systems, the nucleus submedius-ventrolateral orbital cortex-periaque-ductal gray system and motor cortex system, respectively. Multiple neurotransmitters, including opioid, glutamate, GABA and dopamine, are involved in the modulation of pain by these cortical structures. In addition, glial cells may also be in-volved in cortical modulation of pain and serve as one target for pain management research. This review discusses recent studies of pain modulation by these cerebral cortical structures in animals and human.

PROJECTIONS OF THE PARVOCELLULAR RETICULAR-FORMATION TO THE CONTRALATERAL MESENCEPHALIC TRIGEMINAL NUCLEUS IN THE RAT

NARCIS (Netherlands)

MINKELS, RF; JUCH, PJW; TERHORST, GJ; VANWILLIGEN, JD

1991-01-01

Projections of the parvocellular reticular nucleus (PCRt) to the contralateral mesencephalic trigeminal nucleus (Me5) were studied in the rat with neurophysiological and neuroanatomical techniques. Three types of responses (classified by latencies) were recorded extracellularly in the Me5 area after

Increased transient Na+ conductance and action potential output in layer 2/3 prefrontal cortex neurons of the fmr1-/y mouse.

Science.gov (United States)

Routh, Brandy N; Rathour, Rahul K; Baumgardner, Michael E; Kalmbach, Brian E; Johnston, Daniel; Brager, Darrin H

2017-07-01

Layer 2/3 neurons of the prefrontal cortex display higher gain of somatic excitability, responding with a higher number of action potentials for a given stimulus, in fmr1 -/y mice. In fmr1 -/y L2/3 neurons, action potentials are taller, faster and narrower. Outside-out patch clamp recordings revealed that the maximum Na + conductance density is higher in fmr1 -/y L2/3 neurons. Measurements of three biophysically distinct K + currents revealed a depolarizing shift in the activation of a rapidly inactivating (A-type) K + conductance. Realistic neuronal simulations of the biophysical observations recapitulated the elevated action potential and repetitive firing phenotype. Fragile X syndrome is the most common form of inherited mental impairment and autism. The prefrontal cortex is responsible for higher order cognitive processing, and prefrontal dysfunction is believed to underlie many of the cognitive and behavioural phenotypes associated with fragile X syndrome. We recently demonstrated that somatic and dendritic excitability of layer (L) 5 pyramidal neurons in the prefrontal cortex of the fmr1 -/y mouse is significantly altered due to changes in several voltage-gated ion channels. In addition to L5 pyramidal neurons, L2/3 pyramidal neurons play an important role in prefrontal circuitry, integrating inputs from both lower brain regions and the contralateral cortex. Using whole-cell current clamp recording, we found that L2/3 pyramidal neurons in prefrontal cortex of fmr1 -/y mouse fired more action potentials for a given stimulus compared with wild-type neurons. In addition, action potentials in fmr1 -/y neurons were significantly larger, faster and narrower. Voltage clamp of outside-out patches from L2/3 neurons revealed that the transient Na + current was significantly larger in fmr1 -/y neurons. Furthermore, the activation curve of somatic A-type K + current was depolarized. Realistic conductance-based simulations revealed that these biophysical changes in Na

Screening for carcinoma in situ in the contralateral testicle in patients with testicular cancer: a population-based study.

Science.gov (United States)

Kier, M G G; Lauritsen, J; Almstrup, K; Mortensen, M S; Toft, B G; Rajpert-De Meyts, E; Skakkebaek, N E; Rørth, M; von der Maase, H; Agerbaek, M; Holm, N V; Andersen, K K; Dalton, S O; Johansen, C; Daugaard, G

2015-04-01

Screening programmes for contralateral carcinoma in situ (CIS) testis in patients with unilateral germ-cell cancer (GCC) have never been evaluated. We investigated the effect of screening for contralateral CIS in a large nation-wide, population-based study. A contralateral single-site biopsy was offered to 4130 patients in whom GCC had been diagnosed in 1984-2007 (screened cohort); 462 patients in whom GCC was diagnosed in 1984-1988 comprised the unscreened cohort. Cases with CIS were offered radiotherapy. Initially CIS-negative biopsies in patients with metachronous GCC were revised according to today's standards. Risk for metachronous GCC was estimated using cumulative incidence and the Cox proportional hazards model. In the screened cohort, contralateral CIS was found in 181 (4.4%) patients. The cumulative incidence of metachronous GCC after 20 years was 1.9% in the screened cohort and 3.1% in the unscreened cohort (P = 0.097), hazard ratio (HR) for the unscreened cohort: 1.59 (P = 0.144). Expert revision with contemporary methodology of CIS-negative biopsy samples from patients with metachronous cancer revealed CIS in 17 out of 45 (38%) cases. Decreased risks for metachronous GCC were related to older age at diagnosis (HR 0.52 per 10 years, P testicular cancer showed no significant difference in the risk for metachronous GCC between a screened and an unscreened cohort. Single-site biopsy including modern immunohistochemistry does not identify all cases of CIS. © The Author 2014. Published by Oxford University Press on behalf of the European Society for Medical Oncology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

The functional neuroanatomy of object agnosia: a case study.

Science.gov (United States)

Konen, Christina S; Behrmann, Marlene; Nishimura, Mayu; Kastner, Sabine

2011-07-14

Cortical reorganization of visual and object representations following neural injury was examined using fMRI and behavioral investigations. We probed the visual responsivity of the ventral visual cortex of an agnosic patient who was impaired at object recognition following a lesion to the right lateral fusiform gyrus. In both hemispheres, retinotopic mapping revealed typical topographic organization and visual activation of early visual cortex. However, visual responses, object-related, and -selective responses were reduced in regions immediately surrounding the lesion in the right hemisphere, and also, surprisingly, in corresponding locations in the structurally intact left hemisphere. In contrast, hV4 of the right hemisphere showed expanded response properties. These findings indicate that the right lateral fusiform gyrus is critically involved in object recognition and that an impairment to this region has widespread consequences for remote parts of cortex. Finally, functional neural plasticity is possible even when a cortical lesion is sustained in adulthood. Copyright © 2011 Elsevier Inc. All rights reserved.

Anterior transarticular C1-C2 fixation with contralateral screw insertion: a report of two cases and technical note.

Science.gov (United States)

Lvov, Ivan; Grin, Andrey; Kaykov, Aleksandr; Smirnov, Vladimir; Krylov, Vladimir

2017-08-08

Anterior transarticular fixation of the C1-C2 vertebrae is a well-known technique that involves screw insertion through the body of the C2 vertebra into the lateral masses of the atlas through an anterior transcervical approach. Meanwhile, contralateral screw insertion has been previously described only in anatomical studies. We describe two case reports of the clinical application of this new technique. In Case 1, the patient was diagnosed with an unstable C1 fracture. The clinical features of the case did not allow for any type of posterior atlantoaxial fusion, Halo immobilization, or routine anterior fixation using the Reindl and Koller techniques. The possible manner of screw insertion into the anterior third of the right lateral mass was via a contralateral trajectory, which was performed in this case. Case 2 involved a patient with neglected posteriorly dislocated dens fracture who could not lie in the prone position due to concomitant cardiac pathology. Reduction of atlantoaxial dislocation was insufficient, even after scar tissue resection at the fracture, while transdental fusion was not possible. Considering the success of the previous case, atlantoaxial fixation was performed through the small approach, using the Reindl technique and contralateral screw insertion. These two cases demonstrate the potential of anterior transarticular fixation of C1-C2 vertebrae in cases where posterior atlantoaxial fusion is not achievable. This type of fixation can be performed through a single approach if one screw is inserted using the Reindl technique and another is inserted via a contralateral trajectory.

Imaging dose in breast radiotherapy: does breast size affect the dose to the organs at risk and the risk of secondary cancer to the contralateral breast?

International Nuclear Information System (INIS)

Batumalai, Vikneswary; Quinn, Alexandra; Jameson, Michael; Delaney, Geoff; Holloway, Lois

2015-01-01

Correct target positioning is crucial for accurate dose delivery in breast radiotherapy resulting in utilisation of daily imaging. However, the radiation dose from daily imaging is associated with increased probability of secondary induced cancer. The aim of this study was to quantify doses associated with three imaging modalities and investigate the correlation of dose and varying breast size in breast radiotherapy. Planning computed tomography (CT) data sets of 30 breast cancer patients were utilised to simulate the dose received by various organs from a megavoltage computed tomography (MV-CT), megavoltage electronic portal image (MV-EPI) and megavoltage cone-beam computed tomography (MV-CBCT). The mean dose to organs adjacent to the target volume (contralateral breast, lungs, spinal cord and heart) were analysed. Pearson correlation analysis was performed to determine the relationship between imaging dose and primary breast volume and the lifetime attributable risk (LAR) of induced secondary cancer was calculated for the contralateral breast. The highest contralateral breast mean dose was from the MV-CBCT (1.79 Gy), followed by MV-EPI (0.22 Gy) and MV-CT (0.11 Gy). A similar trend was found for all organs at risk (OAR) analysed. The primary breast volume inversely correlated with the contralateral breast dose for all three imaging modalities. As the primary breast volume increases, the likelihood of a patient developing a radiation-induced secondary cancer to the contralateral breast decreases. MV-CBCT showed a stronger relationship between breast size and LAR of developing a radiation-induced contralateral breast cancer in comparison with the MV-CT and MV-EPI. For breast patients, imaging dose to OAR depends on imaging modality and treated breast size. When considering the use of imaging during breast radiotherapy, the patient's breast size and contralateral breast dose should be taken into account

Encoding and retrieval of artificial visuoauditory memory traces in the auditory cortex requires the entorhinal cortex.

Science.gov (United States)

Chen, Xi; Guo, Yiping; Feng, Jingyu; Liao, Zhengli; Li, Xinjian; Wang, Haitao; Li, Xiao; He, Jufang

2013-06-12

Damage to the medial temporal lobe impairs the encoding of new memories and the retrieval of memories acquired immediately before the damage in human. In this study, we demonstrated that artificial visuoauditory memory traces can be established in the rat auditory cortex and that their encoding and retrieval depend on the entorhinal cortex of the medial temporal lobe in the rat. We trained rats to associate a visual stimulus with electrical stimulation of the auditory cortex using a classical conditioning protocol. After conditioning, we examined the associative memory traces electrophysiologically (i.e., visual stimulus-evoked responses of auditory cortical neurons) and behaviorally (i.e., visual stimulus-induced freezing and visual stimulus-guided reward retrieval). The establishment of a visuoauditory memory trace in the auditory cortex, which was detectable by electrophysiological recordings, was achieved over 20-30 conditioning trials and was blocked by unilateral, temporary inactivation of the entorhinal cortex. Retrieval of a previously established visuoauditory memory was also affected by unilateral entorhinal cortex inactivation. These findings suggest that the entorhinal cortex is necessary for the encoding and involved in the retrieval of artificial visuoauditory memory in the auditory cortex, at least during the early stages of memory consolidation.

Organization of visual cortical projections to the claustrum in the cat

International Nuclear Information System (INIS)

Jayaraman, A.; Updyke, B.V.

1979-01-01

The projection patterns from different visual areas of the parieto-occipital cortex to the claustrum were studied autoradiographically in cats. When [ 3 H] was injected into 17, 18, 19 or Clare-Bishop areas, the label was transported to an area restricted to the dorsal and caudal parts of the claustrum without any suggestion of retinotopic organization. Injection in each of these visual areas resulted in individual patterns of projection but with overlapping fields of termination, a pattern similar to corticocaudate projection. When injected into area 7, a region shown to have neurons involved in visuomotor mechanisms, the label was transported to the same area as that of the visual projection. These and other findings suggest that claustrum may be reciprocally and topographically connected with the cerebral cortex. (Auth.)

Contralateral lumbo-umbilical flap: A versatile technique for volar finger coverage

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Akram Hussain Bijli

2017-01-01

Full Text Available Background: While contemplating any difficult soft tissue reconstruction, patient comfort and compliance is of paramount importance. Reconstruction of the volar aspect of fingers and hand by the ipsilateral pedicled flaps (groin flap, abdominal flaps is demanding as the flap inset is difficult for the surgeon and very uncomfortable for the patient. This often leads to flap complications. For the comfort of the patient, better compliance and ease of complete inset, we planned to manage soft tissue defects of the volar aspect of fingers and hand by a new contralateral pedicled lumbo-umbilical flap. This flap is based on the paraumbilical perforators of deep inferior epigastric artery. Materials and Methods: The contralateral pedicled lumbo-umbilical flap was used in eight patients with high-tension electrical burn injuries involving the volar aspect of fingers and hand. The patients were closely observed for first 6 weeks for any flap or donor site complications and then followed monthly to assess donor and recipient site characteristics for 6 months to 2 years. Results and Conclusion: Large flaps up to 8 cm × 16 cm were raised. All but one flaps survived completely. All patients were mobilised within 48 h and five were discharged in less than a week after initial inset. The flap is reliable, easy to harvest and easy to inset on the volar aspect of fingers. The arm is positioned in a very comfortable position. The main disadvantage, however, is a conspicuous abdominal scar.

Contralateral breast cancer adjacent to a fibroadenoma: report of a case.

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Iwamoto, Miki; Takei, Hiroyuki; Iida, Shinya; Yamashita, Kouji; Yanagihara, Keiko; Kurita, Tomoko; Tsuchiya, Shinichi; Kanazawa, Yoshikazu; Uchida, Eiji

2014-01-01

A 64-year-old woman noticed a lump of the right breast and consulted our outpatient clinic. She had undergone multiple excisional biopsies of fibroadenomas in both breasts and mastectomy for invasive ductal carcinoma (IDC) of the left breast. After completing 5 years of treatment with adjuvant tamoxifen, she had undergone screening with annual physical examinations and occasional computed tomography. She was declared recurrence-free 13 years after breast cancer surgery, although lumps were detected in the right breast, probably due to fibroadenomas. Mammography, ultrasonography, and magnetic resonance imaging revealed that the lump was irregularly shaped, 2 cm in diameter, and adjacent to a fibroadenoma with macrocalcification. Two axillary lymph nodes were enlarged and suggestive of metastasis. A core needle biopsy revealed IDC of the right breast. She underwent a right partial mastectomy with axillary lymph node dissection. The IDC was 2 cm in diameter, of nuclear grade 2, and adjacent to a 0.7-cm fibroadenoma with a macrocalcification. The margins of the IDC close to the fibroadenoma were clearly demarcated by the fibrous capsule of the fibroadenoma. Four axillary lymph nodes were positive for metastasis. In the present case the presence of fibroadenoma might have interfered with the early detection of the contralateral IDC. The history of multiple excisions of fibroadenomas and mastectomy for breast cancer suggests an increased risk of contralateral breast cancer for the patient's entire life; therefore, regular annual follow-up, such as physical examinations and mammography, is recommended.

Outcomes of an anatomic total shoulder arthroplasty with a contralateral reverse total shoulder arthroplasty.

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Cox, Ryan M; Padegimas, Eric M; Abboud, Joseph A; Getz, Charles L; Lazarus, Mark D; Ramsey, Matthew L; Williams, Gerald R; Horneff, John G

2018-06-01

It is common for patients to require staged bilateral shoulder arthroplasties. There is a unique cohort of patients who require an anatomic total shoulder arthroplasty (TSA) and a contralateral reverse shoulder arthroplasty (RSA). This study compared the outcomes of patients with a TSA in 1 shoulder and an RSA in the contralateral shoulder. Our institutional database was queried to identify all patients with a TSA and a contralateral RSA. Data collection included patient demographics, preoperative and latest follow-up shoulder range of motion, radiographic analysis, and postoperative complications. Identified patients were assessed at follow-up visits or contacted by phone for functional outcome scores. Nineteen patients met our inclusion/exclusion criteria. There was statistically significant greater internal rotation in the TSA shoulder (P= .044) but no significant difference in forward elevation (P = .573) or external rotation (P= .368). There was no radiographic evidence of humeral or glenoid component loosening of any arthroplasty implants. There were no significant differences between TSA and RSA shoulders for the American Shoulder and Elbow Surgeons Standardized Shoulder Assessment (P= .381), Simple Shoulder Test (P = .352), Single Assessment Numerical Evaluation (P = .709), and visual analog scale satisfaction (P= .448) or pain scores (P= .305). Thirteen patients (68.4%) preferred the RSA side, 1 patient (5.3%; z = 4.04, P < .001) patient preferred the TSA side, and 5 patients expressed no preference. Despite known limitations and differences between TSA and RSA designs, patients who have received both implants are highly satisfied with both. The only parameter in which the TSA had superior outcomes was internal rotation. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Space representation for eye movements is more contralateral in monkeys than in humans

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Kagan, Igor; Iyer, Asha; Lindner, Axel; Andersen, Richard A.

2010-01-01

Contralateral hemispheric representation of sensory inputs (the right visual hemifield in the left hemisphere and vice versa) is a fundamental feature of primate sensorimotor organization, in particular the visuomotor system. However, many higher-order cognitive functions in humans show an asymmetric hemispheric lateralization—e.g., right brain specialization for spatial processing—necessitating a convergence of information from both hemifields. Electrophysiological studies in monkeys and fun...

Task-Relevant Information Modulates Primary Motor Cortex Activity Before Movement Onset.

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Calderon, Cristian B; Van Opstal, Filip; Peigneux, Philippe; Verguts, Tom; Gevers, Wim

2018-01-01

Monkey neurophysiology research supports the affordance competition hypothesis (ACH) proposing that cognitive information useful for action selection is integrated in sensorimotor areas. In this view, action selection would emerge from the simultaneous representation of competing action plans, in parallel biased by relevant task factors. This biased competition would take place up to primary motor cortex (M1). Although ACH is plausible in environments affording choices between actions, its relevance for human decision making is less clear. To address this issue, we designed an functional magnetic resonance imaging (fMRI) experiment modeled after monkey neurophysiology studies in which human participants processed cues conveying predictive information about upcoming button presses. Our results demonstrate that, as predicted by the ACH, predictive information (i.e., the relevant task factor) biases activity of primary motor regions. Specifically, first, activity before movement onset in contralateral M1 increases as the competition is biased in favor of a specific button press relative to activity in ipsilateral M1. Second, motor regions were more tightly coupled with fronto-parietal regions when competition between potential actions was high, again suggesting that motor regions are also part of the biased competition network. Our findings support the idea that action planning dynamics as proposed in the ACH are valid both in human and non-human primates.

Motor cortex and spinal cord neuromodulation promote corticospinal tract axonal outgrowth and motor recovery after cervical contusion spinal cord injury.

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Zareen, N; Shinozaki, M; Ryan, D; Alexander, H; Amer, A; Truong, D Q; Khadka, N; Sarkar, A; Naeem, S; Bikson, M; Martin, J H

2017-11-01

Cervical injuries are the most common form of SCI. In this study, we used a neuromodulatory approach to promote skilled movement recovery and repair of the corticospinal tract (CST) after a moderately severe C4 midline contusion in adult rats. We used bilateral epidural intermittent theta burst (iTBS) electrical stimulation of motor cortex to promote CST axonal sprouting and cathodal trans-spinal direct current stimulation (tsDCS) to enhance spinal cord activation to motor cortex stimulation after injury. We used Finite Element Method (FEM) modeling to direct tsDCS to the cervical enlargement. Combined iTBS-tsDCS was delivered for 30min daily for 10days. We compared the effect of stimulation on performance in the horizontal ladder and the Irvine Beattie and Bresnahan forepaw manipulation tasks and CST axonal sprouting in injury-only and injury+stimulation animals. The contusion eliminated the dorsal CST in all animals. tsDCS significantly enhanced motor cortex evoked responses after C4 injury. Using this combined spinal-M1 neuromodulatory approach, we found significant recovery of skilled locomotion and forepaw manipulation skills compared with injury-only controls. The spared CST axons caudal to the lesion in both animal groups derived mostly from lateral CST axons that populated the contralateral intermediate zone. Stimulation enhanced injury-dependent CST axonal outgrowth below and above the level of the injury. This dual neuromodulatory approach produced partial recovery of skilled motor behaviors that normally require integration of posture, upper limb sensory information, and intent for performance. We propose that the motor systems use these new CST projections to control movements better after injury. Copyright © 2017 Elsevier Inc. All rights reserved.

Adaptive changes in the motor cortex during and after longterm forelimb immobilization in adult rats.

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Viaro, Riccardo; Budri, Mirco; Parmiani, Pierantonio; Franchi, Gianfranco

2014-05-15

Experimental and clinical studies have attempted to evaluate the changes in cortical activity seen after immobilization-induced longterm sensorimotor restriction, although results remain controversial. We used intracortical microstimulation (ICMS), which provides topographic movement representations of the motor areas in both hemispheres with optimal spatial characterization, combined with behavioural testing to unravel the effects of limb immobilization on movement representations in the rat primary motor cortex (M1). Unilateral forelimb immobilization in rats was achieved by casting the entire limb and leaving the cast in place for 15 or 30 days. Changes in M1 were bilateral and specific for the forelimb area, but were stronger in the contralateral-to-cast hemisphere. The threshold current required to evoke forelimb movement increased progressively over the period in cast, whereas the forelimb area size decreased and the non-excitable area size increased. Casting resulted in a redistribution of proximal/distal movement representations: proximal forelimb representation increased, whereas distal representation decreased in size. ICMS after cast removal showed a reversal of changes, which remained partial at 15 days. Local application of the GABAA-antagonist bicuculline revealed the impairment of cortical synaptic connectivity in the forelimb area during the period of cast and for up to 15 days after cast removal. Six days of rehabilitation using a rotarod performance protocol after cast removal did not advance map size normalization in the contralateral-to-cast M1 and enabled the cortical output towards the distal forelimb only in sites that had maintained their excitability. These results are relevant to our understanding of adult M1 plasticity during and after sensorimotor deprivation, and to new approaches to conditions that require longterm limb immobilization. © 2014 The Authors. The Journal of Physiology © 2014 The Physiological Society.

Primary infiltrating ductal carcinoma of the axillary breast with metastasis to the contralateral chest wall

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Li-Min Sun

2013-06-01

Full Text Available Primary infiltrating ductal carcinoma of the axillary breast is rare and has a high frequency of lymph node (LN involvement. We report a woman with primary infiltrating ductal carcinoma arising from the right axillary breast with metastasis to the contralateral chest wall. Excisional biopsy of the left chest wall nodule and the right axillary mass was carried out and both showed invasive ductal carcinomas histologically. The lesion of the right axillary mass arose from the breast tissue, rather than the LN. Further surgery proved the right axillary LN metastasis. After further review, a primary infiltrating ductal carcinoma of the right axillary breast with metastasis to axillary LNs and contralateral chest wall was diagnosed. The patient also received chemotherapy and radiation and there was no evidence of tumor recurrence after treatment. The present report demonstrated a rare case with uncommon manifestation. Lesions of uncertain origin around the periphery of the breast should be suspected for breast carcinoma.

Hip dislocation in cerebral palsy: evolution of the contralateral side after reconstructive surgery

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João Caetano Munhoz Abdo

2016-06-01

Full Text Available ABSTRACT OBJECTIVE: To evaluate the progression of the contralateral hip after unilateral reconstruction of hip dislocation in patients classified as GMFCS IV-V; and to identify potential prognostic factors for their evolution. METHODS: This was a retrospective study on 17 patients with spastic cerebral palsy, who were classified on the GMFCS scale (Gross Motor Functional Classification System as degrees IV and V, and who underwent unilateral reconstruction surgery to treat hip dislocation (adductor release, femoral varus osteotomy and acetabuloplasty. The minimum postoperative follow-up was 30 months. The clinical parameters evaluated were sex, age at time of surgery, length of follow-up after surgery and range of abduction. The treatment parameters were use/nonuse of femoral shortening, application of botulinum toxin and any previous muscle releases. The radiographic parameters were Reimer's extrusion index (REI, acetabular angle (AA and the continuity of Shenton's line. RESULTS: Among the 17 patients evaluated, eight presented dislocation (group I and nine did not (group II. Group I comprised three males and five females; group II comprised one male and eight females. The mean age at the time of surgery among the group I patients was 62 months and the mean follow-up was 62 months. In group II, these were 98 and 83 months, respectively. There was a trend in which patients of greater age did not evolve with contralateral dislocation. Among the nine patients with the combination of REI < 30% and AA < 25°, only one presented dislocation during the follow-up. Contralateral subluxation occurred within the first two years after the surgery. CONCLUSION: Hips presenting REI < 30° and AA < 25° do not tend to evolve to subluxation and can be kept under observation. Preoperative clinical and radiographic measurements alone are not useful for indicating the natural evolution of non- operated hips. The critical period for subluxation is the first two

Contralateral Vocal Fold Reactive Lesions: Nomenclature, Treatment Choice, and Outcome.

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Koss, Shira L; Kidwai, Sarah M; Pitman, Michael J

2016-06-01

Contralateral reactive lesions (RLs) represent a distinct entity among benign bilateral vocal fold (VF) lesions. Lack of uniform nomenclature and a myriad of surgical options have hampered attempts to develop treatment guidelines. The objective of this study is to better define RLs and their prognosis, through the development of a standard nomenclature, with an aim to guide treatment and delineate the role of phonosurgery. Case series with chart review. Tertiary care center. Analysis was performed on patients with Current Procedural Terminology code 31545. Operative reports with a primary lesion and contralateral RL were included. Outcomes included the Voice Handicap Index-10 (VHI-10) and GRBAS (grade, roughness, breathiness, asthenia, and strain) scale, lesion persistence/recurrence, mucosal wave, and edge character based on blinded videostroboscopy review. A nomenclature was developed based on intraoperative RLs (n = 30), defined by lesion consistency (fibrous or polypoid) and relationship to normal VF edge (gradual or steep). Reactive lesion treatment included no intervention, excision, potassium titanyl phosphate laser, steroid injection, or a combination thereof. Observations included the following: inconsistent treatment modalities were employed, excision of RLs did not yield better outcomes, fibrous RLs were more likely to persist and polypoid lesions more likely to recur, gradual lesions were more likely to remain disease free, and most treatments showed improved mucosal wave, VHI-10, and GRBAS. Reactive lesions have not been well classified, and treatments are based on subjective intraoperative decision making with unpredictable outcomes. The nomenclature proposed will allow for a better definition of the RL and provide a framework for future research to identify optimal treatment. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2016.

Chemosensory Learning in the Cortex

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Edmund eRolls

2011-09-01

Full Text Available Taste is a primary reinforcer. Olfactory-taste and visual-taste association learning takes place in the primate including human orbitofrontal cortex to build representations of flavour. Rapid reversal of this learning can occur using a rule-based learning system that can be reset when an expected taste or flavour reward is not obtained, that is by negative reward prediction error, to which a population of neurons in the orbitofrontal cortex responds. The representation in the orbitofrontal cortex but not the primary taste or olfactory cortex is of the reward value of the visual / olfactory / taste / input as shown by devaluation experiments in which food is fed to satiety, and by correlations with the activations with subjective pleasantness ratings in humans. Sensory-specific satiety for taste, olfactory, visual, and oral somatosensory inputs produced by feeding a particular food to satiety are implemented it is proposed by medium-term synaptic adaptation in the orbitofrontal cortex. Cognitive factors, including word-level descriptions, modulate the representation of the reward value of food in the orbitofrontal cortex, and this effect is learned it is proposed by associative modification of top-down synapses onto neurons activated by bottom-up taste and olfactory inputs when both are active in the orbitofrontal cortex. A similar associative synaptic learning process is proposed to be part of the mechanism for the top-down attentional control to the reward value vs the sensory properties such as intensity of taste and olfactory inputs in the orbitofrontal cortex, as part of a biased activation theory of selective attention.

Figure-ground processing during fixational saccades in V1: indication for higher-order stability.

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Gilad, Ariel; Pesoa, Yair; Ayzenshtat, Inbal; Slovin, Hamutal

2014-02-26

In a typical visual scene we continuously perceive a "figure" that is segregated from the surrounding "background" despite ongoing microsaccades and small saccades that are performed when attempting fixation (fixational saccades [FSs]). Previously reported neuronal correlates of figure-ground (FG) segregation in the primary visual cortex (V1) showed enhanced activity in the "figure" along with suppressed activity in the noisy "background." However, it is unknown how this FG modulation in V1 is affected by FSs. To investigate this question, we trained two monkeys to detect a contour embedded in a noisy background while simultaneously imaging V1 using voltage-sensitive dyes. During stimulus presentation, the monkeys typically performed 1-3 FSs, which displaced the contour over the retina. Using eye position and a 2D analytical model to map the stimulus onto V1, we were able to compute FG modulation before and after each FS. On the spatial cortical scale, we found that, after each FS, FG modulation follows the stimulus retinal displacement and "hops" within the V1 retinotopic map, suggesting visual instability. On the temporal scale, FG modulation is initiated in the new retinotopic position before it disappeared from the old retinotopic position. Moreover, the FG modulation developed faster after an FS, compared with after stimulus onset, which may contribute to visual stability of FG segregation, along the timeline of stimulus presentation. Therefore, despite spatial discontinuity of FG modulation in V1, the higher-order stability of FG modulation along time may enable our stable and continuous perception.

Generalized seizures and transient contralateral hemiparesis following retrobulbar anesthesia: a case report.

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Dettoraki, Maria; Dimitropoulou, Chrisafoula; Nomikarios, Nikolaos; Moschos, Marilita M; Brοuzas, Dimitrios

2015-07-28

Retrobulbar block is a local anesthetic technique widely used for intraocular surgery. Although retrobulbar anesthesia is considered to be relatively safe, a number of serious adverse events have been reported. To our knowledge, immediate onset of generalized seizures with contralateral hemiparesis after retrobulbar anesthesia has not been reported. A 62-year-old Caucasian healthy male with a right eye retinal detachment was admitted for pars plana vitrectomy. During retrobulbar anesthesia with ropivacaine and before needle withdrawal, the patient developed twitching of the face which rapidly progressed to generalized tonic-clonic seizures. Arterial oxygen saturation decreased to 75 %. Chin lift was performed and 100 % oxygen was administrated via face mask, which increased saturation to 99 %. Midazolam 2 mg was administrated intravenously to control seizures. After cessation of seizures, left-sided hemiparesis was evident. Brain computed tomography and electroencephalogram were normal 3 h later. The patient underwent pars plana vitrectomy under general anesthesia 4 days later. Serious complications of local anesthesia for ophthalmic surgery are uncommon. We present a case in which generalized tonic-clonic seizures developed during retrobulbar anesthesia, followed by transient contralateral hemiparesis. The early onset of seizures indicated intra-arterial injection of the anesthetic. Our case suggested the need for close monitoring during the performance of retrobulbar anesthesia and the presence of well-trained personnel for early recognition and immediate management of the complications.

Emphysema lung lobe volume reduction: effects on the ipsilateral and contralateral lobes

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Brown, Matthew S.; Kim, Hyun J.; Abtin, Fereidoun G.; Galperin-Aizenberg, Maya; Pais, Richard; Da Costa, Irene G.; Ordookhani, Arash; Chong, Daniel; Ni, Chiayi; McNitt-Gray, Michael F.; Goldin, Jonathan G. [David Geffen School of Medicine at UCLA, Center for Computer Vision and Imaging Biomarkers, Department of Radiological Sciences, Los Angeles, CA (United States); Strange, Charlie [Medical University of South Carolina, Department of Pulmonary and Critical Care Medicine, Columbia, SC (United States); Tashkin, Donald P. [David Geffen School of Medicine at UCLA, Division of Pulmonary and Critical Care Medicine, Los Angeles, CA (United States)

2012-07-15

To investigate volumetric and density changes in the ipsilateral and contralateral lobes following volume reduction of an emphysematous target lobe. The study included 289 subjects with heterogeneous emphysema, who underwent bronchoscopic volume reduction of the most diseased lobe with endobronchial valves and 132 untreated controls. Lobar volume and low-attenuation relative area (RA) changes post-procedure were measured from computed tomography images. Regression analysis (Spearman's rho) was performed to test the association between change in the target lobe volume and changes in volume and density variables in the other lobes. The target lobe volume at full inspiration in the treatment group had a mean reduction of -0.45 L (SE = 0.034, P < 0.0001), and was associated with volume increases in the ipsilateral lobe (rho = -0.68, P < 0.0001) and contralateral lung (rho = -0.16, P = 0.006), and overall reductions in expiratory RA (rho = 0.31, P < 0.0001) and residual volume (RV)/total lung capacity (TLC) (rho = 0.13, P = 0.03). When the volume of an emphysematous target lobe is reduced, the volume is redistributed primarily to the ipsilateral lobe, with an overall reduction. Image-based changes in lobar volumes and densities indicate that target lobe volume reduction is associated with statistically significant overall reductions in air trapping, consistent with expansion of the healthier lung. (orig.)

Emphysema lung lobe volume reduction: effects on the ipsilateral and contralateral lobes

International Nuclear Information System (INIS)

Brown, Matthew S.; Kim, Hyun J.; Abtin, Fereidoun G.; Galperin-Aizenberg, Maya; Pais, Richard; Da Costa, Irene G.; Ordookhani, Arash; Chong, Daniel; Ni, Chiayi; McNitt-Gray, Michael F.; Goldin, Jonathan G.; Strange, Charlie; Tashkin, Donald P.

2012-01-01

To investigate volumetric and density changes in the ipsilateral and contralateral lobes following volume reduction of an emphysematous target lobe. The study included 289 subjects with heterogeneous emphysema, who underwent bronchoscopic volume reduction of the most diseased lobe with endobronchial valves and 132 untreated controls. Lobar volume and low-attenuation relative area (RA) changes post-procedure were measured from computed tomography images. Regression analysis (Spearman's rho) was performed to test the association between change in the target lobe volume and changes in volume and density variables in the other lobes. The target lobe volume at full inspiration in the treatment group had a mean reduction of -0.45 L (SE = 0.034, P < 0.0001), and was associated with volume increases in the ipsilateral lobe (rho = -0.68, P < 0.0001) and contralateral lung (rho = -0.16, P = 0.006), and overall reductions in expiratory RA (rho = 0.31, P < 0.0001) and residual volume (RV)/total lung capacity (TLC) (rho = 0.13, P = 0.03). When the volume of an emphysematous target lobe is reduced, the volume is redistributed primarily to the ipsilateral lobe, with an overall reduction. Image-based changes in lobar volumes and densities indicate that target lobe volume reduction is associated with statistically significant overall reductions in air trapping, consistent with expansion of the healthier lung. (orig.)

Distinct timescales of population coding across cortex.

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Runyan, Caroline A; Piasini, Eugenio; Panzeri, Stefano; Harvey, Christopher D

2017-08-03

The cortex represents information across widely varying timescales. For instance, sensory cortex encodes stimuli that fluctuate over few tens of milliseconds, whereas in association cortex behavioural choices can require the maintenance of information over seconds. However, it remains poorly understood whether diverse timescales result mostly from features intrinsic to individual neurons or from neuronal population activity. This question remains unanswered, because the timescales of coding in populations of neurons have not been studied extensively, and population codes have not been compared systematically across cortical regions. Here we show that population codes can be essential to achieve long coding timescales. Furthermore, we find that the properties of population codes differ between sensory and association cortices. We compared coding for sensory stimuli and behavioural choices in auditory cortex and posterior parietal cortex as mice performed a sound localization task. Auditory stimulus information was stronger in auditory cortex than in posterior parietal cortex, and both regions contained choice information. Although auditory cortex and posterior parietal cortex coded information by tiling in time neurons that were transiently informative for approximately 200 milliseconds, the areas had major differences in functional coupling between neurons, measured as activity correlations that could not be explained by task events. Coupling among posterior parietal cortex neurons was strong and extended over long time lags, whereas coupling among auditory cortex neurons was weak and short-lived. Stronger coupling in posterior parietal cortex led to a population code with long timescales and a representation of choice that remained consistent for approximately 1 second. In contrast, auditory cortex had a code with rapid fluctuations in stimulus and choice information over hundreds of milliseconds. Our results reveal that population codes differ across cortex

Expression of glial fibrillar acidic protein in the sensorimotor cortex of the cerebral hemispheres in the modeling of transient ischemia against the background of previous sensitization by brain antigen and immunocorrection

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L. M. Yaremenko

2017-12-01

Full Text Available Aim. In order to analyze the dynamics of expression of glial fibrillar acidic protein in the sensorimotor cortex of the large hemispheres in the simulation of transient ischemia against the background of previous sensitization by brain antigen and immunocorrection. Materials and methods. The study is conducted on 185 male mature white rats from Wistar line weighing 260-290 g, in which the damage of the brain was modulated. The brain for study was taken on the 1st, 3rd, 10th, 30th and 90th days after the start of the experiment. The histological, immunohistochemical, morphometric and statistical methods were used. Results. Observations have shown that sensitization by the brain antigen causes neurodegenerative changes in the sensorimotor cortex and a moderate increase in the number of GFAP+-gliocytes, which is gradually increasing. The discirculatory changes that occurred with PO and BCA against the background of previous sensitization practically do not lead to changes in the number of GFAP+-cells. Against the background of sensitization by brain antigen, brain ischemia leads to an increase in the number of gliocytes that are GFAP labeled. In the affected hemisphere, their number reaches a maximum in the end of the acute period of ischemia, after which it decreases. But even in 3 months after transient vascular lesion, there are almost twice as many as in conditionally intact rats. This can be a factor that will significantly affect the function of brain regions after a vascular accident. The increase in the number of GFAP+-gliocytes in the contralateral hemisphere allows us to speak about a certain systemic response of astrocytic glia after ischemic trauma. An early reaction to increase of the number of labeled astrocytes just a day after ischemic attack suggests that some of this type of gliocytes does not expresses GFAP under normal conditions. The action of Imunofan in MEAs results in a less significant decrease in manifestations of

Electrical stimulation of the insular cortex as a novel target for the relief of refractory pain: An experimental approach in rodents.

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Dimov, Luiz Fabio; Toniolo, Elaine Flamia; Alonso-Matielo, Heloísa; de Andrade, Daniel Ciampi; Garcia-Larrea, Luis; Ballester, Gerson; Teixeira, Manoel Jacobsen; Dale, Camila Squarzoni

2018-07-02

Cortical electrical stimulation (CES) has shown to be an effective therapeutic alternative for neuropathic pain refractory to pharmacological treatment. The primary motor cortex(M1) was the main cortical target used in the vast majority of both invasive and non-invasive studies. Despite positive results M1-based approaches still fail to relieve pain in a significant proportion of individuals. It has been advocated that the direct stimulation of cortical areas directly implicated in the central integration of pain could increase the efficacy of analgesic brain stimulation. Here, we evaluated the behavioral effects of electrical stimulation of the insular cortex (ESI) on pain sensitivity in an experimental rat model of peripheral neuropathy, and have described the pathways involved. Animals underwent chronic constriction of the sciatic nerve in the right hind limb and had concentric electrodes implanted in the posterior dysranular insular cortex. Mechanical nociception responses were evaluated before and at the end of a 15-min session of ESI (60Hz, 210μs, 1V). ESI reversed mechanical hypersensitivity in the paw contralateral to the brain hemisphere stimulated, without inducing motor impairment in the open-field test. Pharmacological blockade of μ-opioid (MOR) or type 1-cannabinoid receptors (CB1R) abolished ESI-induced antinociceptive effects. Evaluation of CB1R and MOR spatial expression demonstrated differential modulation of CB1R and MOR in the periaqueductal gray matter (PAG) of ESI-treated rats in sub-areas involved in pain processing/modulation. These results indicate that ESI induces antinociception by functionally modulating opioid and cannabinoid systems in the PAG pain circuitry in rats with experimentally induced neuropathic pain. Copyright © 2017 Elsevier B.V. All rights reserved.

Motor skills training promotes motor functional recovery and induces synaptogenesis in the motor cortex and striatum after intracerebral hemorrhage in rats.

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Tamakoshi, Keigo; Ishida, Akimasa; Takamatsu, Yasuyuki; Hamakawa, Michiru; Nakashima, Hiroki; Shimada, Haruka; Ishida, Kazuto

2014-03-01

We investigated the effects of motor skills training on several types of motor function and synaptic plasticity following intracerebral hemorrhage (ICH) in rats. Male Wistar rats were injected with collagenase into the left striatum to induce ICH, and they were randomly assigned to the ICH or sham groups. Each group was divided into the motor skills training (acrobatic training) and control (no exercise) groups. The acrobatic group performed acrobatic training from 4 to 28 days after surgery. Motor functions were assessed by motor deficit score, the horizontal ladder test and the wide or narrow beam walking test at several time points after ICH. The number of ΔFosB-positive cells was counted using immunohistochemistry to examine neuronal activation, and the PSD95 protein levels were analyzed by Western blotting to examine synaptic plasticity in the bilateral sensorimotor cortices and striata at 14 and 29 days after ICH. Motor skills training following ICH significantly improved gross motor function in the early phase after ICH and skilled motor coordinated function in the late phase. The number of ΔFosB-positive cells in the contralateral sensorimotor cortex in the acrobatic group significantly increased compared to the control group. PSD95 protein expression in the motor cortex significantly increased in the late phase, and in the striatum, the protein level significantly increased in the early phase by motor skills training after ICH compared to no training after ICH. We demonstrated that motor skills training improved motor function after ICH in rats and enhanced the neural activity and synaptic plasticity in the striatum and sensorimotor cortex. Copyright © 2013 Elsevier B.V. All rights reserved.

Risks of subsequent contralateral fractures of the trochanteric region in elderly.

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Pogliacomi, Francesco; Pellegrini, Andrea; Tacci, Fabrizio; Pedrini, Martina Francesca; Costantino, Cosimo; Pedrazzini, Alessio; Pedrazzi, Giuseppe; Lauretani, Fulvio; Vaienti, Enrico; Ceccarelli, Francesco

2017-01-16

Fractures in elderly are always a dramatic event and the healing is often not complete. In a context of bone fragility, repeated fractures are a growing problem in the industrialized world, in which the mean age of population is increasing. The aim of this study was to identify those general factors which may increase the risk of subsequent trochanteric fractures after an initial lesion. Three-hundred and thirty-one patients who underwent intramedullary fixation for trochanteric fractures between January 2012 and December 2013 were studied. Forty subjects yet alive (group 1), affected by a subsequent contralateral hip fracture, were compared with 202 patients (group 2) affected by isolated trochanteric fracture. Days of hospitalization before surgery, hospitalization, period of rehabilitation, type of discharge and comorbidities, that are reported in literature as possible risk factors for hip refracture, were analyzed. In addition, all patients were interviewed in order to assess if a therapy for osteoporosis was prescribed after the initial fracture and how their gait had been modified by fractures. Days of hospitalization before surgery, hospitalization, period of rehabilitation and type of discharge were not predictive factors for subsequent fractures, as well as diabetes mellitus, hypertension and cardiac diseases. The presence of neurologic and respiratory diseases were associated to a higher risk of refractures, as well as the absence of specific medical treatment for osteoporosis. Neurologic and respiratory comorbidities and the absence of osteoporosis medical treatment are the variables associated to a higher risk of contralateral fractures. Physicians can do more in terms of prevention and strategies must consider these risk factors.

Effect of epileptogenic agents on the incorporation of /sup 3/H-glycine into proteins in the cat's cerebral cortex

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Rojik, I.; Feher, O.

1982-06-01

Filter paper strips soaked in /sup 3/H-glycine solution were applied to acoustic cortex of cats, anaesthetized with Nembutal and pretreated with epileptogenic agents (Metrazol, G-penicillin, and 3-amino-pyridine) and cycloheximide. The untreated contralateral hemisphere served as control. After 1 h incubation, both cortical samples were excised simultaneously and fixed in Bouin solution for autoradiography. Incorporation was blocked by cycloheximide. There was no glycine incorporation on the penicillin-treated side, while pyramidal cells were intensively labelled in layers II-V of the mirror focus. 3-Aminopyridine produced the same result. Metrazol as convulsant proved to be far weaker than the previous two. The intensity of incorporation was significantly more intensive in the mirror focus than in the primary one. Penicillin and 3-aminopyridine, while provoking cortical seizures, seem to inhibit glycine incorporation into a neuron-specific, function-dependent protein contained by the labelled cells in the autoradiogram.

Benefit of a Contralateral Routing of Signal Device for Unilateral Cochlear Implant Users.

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Weder, Stefan; Kompis, Martin; Caversaccio, Marco; Stieger, Christof

2014-01-01

Objective: To investigate objective and subjective effects of an adjunctive contralateral routing of signal (CROS) device at the untreated ear in patients with a unilateral cochlear implant (CI). Design: Prospective study of 10 adult experienced unilateral CI users with bilateral severe-to-profound hearing loss. Speech in noise reception (SNR) and sound localization were measured with and without the additional CROS device. SNR was measured by applying speech signals at the untreated/CROS sid...

Altered contralateral sensorimotor system organization after experimental hemispherectomy: a structural and functional connectivity study.

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Otte, Willem M; van der Marel, Kajo; van Meer, Maurits P A; van Rijen, Peter C; Gosselaar, Peter H; Braun, Kees P J; Dijkhuizen, Rick M

2015-08-01

Hemispherectomy is often followed by remarkable recovery of cognitive and motor functions. This reflects plastic capacities of the remaining hemisphere, involving large-scale structural and functional adaptations. Better understanding of these adaptations may (1) provide new insights in the neuronal configuration and rewiring that underlies sensorimotor outcome restoration, and (2) guide development of rehabilitation strategies to enhance recovery after hemispheric lesioning. We assessed brain structure and function in a hemispherectomy model. With MRI we mapped changes in white matter structural integrity and gray matter functional connectivity in eight hemispherectomized rats, compared with 12 controls. Behavioral testing involved sensorimotor performance scoring. Diffusion tensor imaging and resting-state functional magnetic resonance imaging were acquired 7 and 49 days post surgery. Hemispherectomy caused significant sensorimotor deficits that largely recovered within 2 weeks. During the recovery period, fractional anisotropy was maintained and white matter volume and axial diffusivity increased in the contralateral cerebral peduncle, suggestive of preserved or improved white matter integrity despite overall reduced white matter volume. This was accompanied by functional adaptations in the contralateral sensorimotor network. The observed white matter modifications and reorganization of functional network regions may provide handles for rehabilitation strategies improving functional recovery following large lesions.

Positron computed tomography studies of cerebral metabolic responses to complex motor tasks

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Phelps, M.E.; Mazziotta, J.C.

1984-01-01

Human motor system organization was explored in 8 right-handed male subjects using /sup 18/F-fluorodeoxyglucose and positron computed tomography to measure cerebral glucose metabolism. Five subjects had triple studies (eyes closed) including: control (hold pen in right hand without moving), normal size writing (subject repeatedly writes name) and large (10-15 X normal) name writing. In these studies normal and large size writing had a similar distribution of metabolic responses when compared to control studies. Activations (percent change from control) were in the range of 12-20% and occurred in the striatum bilaterally > contralateral Rolandic cortex > contralateral thalamus. No significant activations were observed in the ipsilateral thalamus, Rolandic cortex or cerebellum (supplementary motor cortex was not examined). The magnitude of the metabolic response in the striatum was greater with the large versus normal sized writing. This differential response may be due to an increased number and topographic distribution of neurons responding with the same average activity between tasks or an increase in the functional activity of the same neuronal population between the two tasks (present spatial resolution inadequate to differentiate). When subjects (N=3) performed novel sequential finger movements, the maximal metabolic response was in the contralateral Rolandic cortex > striatum. Such studies provide a means of exploring human motor system organization, motor learning and provide a basis for examining patients with motor system disorders

Contralateral delay activity provides a neural measure of the number of representations in visual working memory.

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Ikkai, Akiko; McCollough, Andrew W; Vogel, Edward K

2010-04-01

Visual working memory (VWM) helps to temporarily represent information from the visual environment and is severely limited in capacity. Recent work has linked various forms of neural activity to the ongoing representations in VWM. One piece of evidence comes from human event-related potential studies, which find a sustained contralateral negativity during the retention period of VWM tasks. This contralateral delay activity (CDA) has previously been shown to increase in amplitude as the number of memory items increases, up to the individual's working memory capacity limit. However, significant alternative hypotheses remain regarding the true nature of this activity. Here we test whether the CDA is modulated by the perceptual requirements of the memory items as well as whether it is determined by the number of locations that are being attended within the display. Our results provide evidence against these two alternative accounts and instead strongly support the interpretation that this activity reflects the current number of objects that are being represented in VWM.

Assessment of contralateral neck failure in 229 cases of carcinoma of the tonsillar region treated with techniques designed to spare contralateral parotid function

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O'Sullivan, B.; Warde, P.; Grice, B.; Goh, C.; Keane, T.; Payne, D.; Liu, F-F.; McLean, M.; Waldron, J.; Cummings, B.

1996-01-01

Purpose/Objective: Radiation-induced xerostomia is a frequent cause of morbidity in head and neck cancer patients. To minimize this complication unilateral techniques (UT) designed to treat the primary tumor and ipsilateral neck have been used for many years in selected cases at our institution. Although such techniques exclude the contralateral parotid from the high dose target volume, they also leave the contralateral neck nodes untreated. The purpose of the study was to evaluate the risk of failure in the opposite neck. Materials and Methods: We identified 229 patients treated with UT from a series of 641 cases with carcinoma of the tonsillar region treated with curative intent between 1970 and 1991. Detailed documentation of the tumor, the radiation dosimetry, the sites of failure, and outcome including local, regional, and distant failure, and late complications, were performed. Actuarial 5-year plots were used to calculate local control, regional control, and survival rates. Results: Median age was 61 years (74 females/155 males); median follow-up 8 years (range 6 months to 21 years). AJCC (1992) T categories were T1:73, T2:120, T3:30, T4:6. The N category distribution was: N0:136, N1:53, N2a:29, N2b:8, and N3:8 cases. Base of tongue and palate were involved in 49 and 82 cases respectively. Irradiation techniques consisted of ipsilateral wedge pairs with Cobalt of 6MV photons in 210 cases (92%), while the remainder were electrons with or without photons. Customized compensators were used in the majority of cases in addition to the use of wedge filters. 75% received 50 Gy in 4 weeks, 10% received 60 Gy in 6 weeks, while the remainder received other doses intended to be curative. A radioactive implant was also used in 20 patients. The 5-year actuarial rates were as follows: overall local control: 76%, regional node control: 80%; cause specific survival: 80%. A total of 7 patients manifested regional disease in the opposite neck (crude rate of 3% or 7 of 229

Contralateral white noise attenuates 40-Hz auditory steady-state fields but not N100m in auditory evoked fields.

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Kawase, Tetsuaki; Maki, Atsuko; Kanno, Akitake; Nakasato, Nobukazu; Sato, Mika; Kobayashi, Toshimitsu

2012-01-16

The different response characteristics of the different auditory cortical responses under conventional central masking conditions were examined by comparing the effects of contralateral white noise on the cortical component of 40-Hz auditory steady state fields (ASSFs) and the N100 m component in auditory evoked fields (AEFs) for tone bursts using a helmet-shaped magnetoencephalography system in 8 healthy volunteers (7 males, mean age 32.6 years). The ASSFs were elicited by monaural 1000 Hz amplitude modulation tones at 80 dB SPL, with the amplitude modulated at 39 Hz. The AEFs were elicited by monaural 1000 Hz tone bursts of 60 ms duration (rise and fall times of 10 ms, plateau time of 40 ms) at 80 dB SPL. The results indicated that continuous white noise at 70 dB SPL presented to the contralateral ear did not suppress the N100 m response in either hemisphere, but significantly reduced the amplitude of the 40-Hz ASSF in both hemispheres with asymmetry in that suppression of the 40-Hz ASSF was greater in the right hemisphere. Different effects of contralateral white noise on these two responses may reflect different functional auditory processes in the cortices. Copyright © 2011 Elsevier Inc. All rights reserved.

Rod-like microglia are restricted to eyes with laser-induced ocular hypertension but absent from the microglial changes in the contralateral untreated eye.

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Rosa de Hoz

Full Text Available In the mouse model of unilateral laser-induced ocular hypertension (OHT the microglia in both the treated and the normotensive untreated contralateral eye have morphological signs of activation and up-regulation of MHC-II expression in comparison with naïve. In the brain, rod-like microglia align to less-injured neurons in an effort to limit damage. We investigate whether: i microglial activation is secondary to laser injury or to a higher IOP and; ii the presence of rod-like microglia is related to OHT. Three groups of mice were used: age-matched control (naïve, n=15; and two lasered: limbal (OHT, n=15; and non-draining portion of the sclera (scleral, n=3. In the lasered animals, treated eyes as well as contralateral eyes were analysed. Retinal whole-mounts were immunostained with antibodies against, Iba-1, NF-200, MHC-II, CD86, CD68 and Ym1. In the scleral group (normal ocular pressure no microglial signs of activation were found. Similarly to naïve eyes, OHT-eyes and their contralateral eyes had ramified microglia in the nerve-fibre layer related to the blood vessel. However, only eyes with OHT had rod-like microglia that aligned end-to-end, coupling to form trains of multiple cells running parallel to axons in the retinal surface. Rod-like microglia were CD68+ and were related to retinal ganglion cells (RGCs showing signs of degeneration (NF-200+RGCs. Although MHC-II expression was up-regulated in the microglia of the NFL both in OHT-eyes and their contralateral eyes, no expression of CD86 and Ym1 was detected in ramified or in rod-like microglia. After 15 days of unilateral lasering of the limbal and the non-draining portion of the sclera, activated microglia was restricted to OHT-eyes and their contralateral eyes. However, rod-like microglia were restricted to eyes with OHT and degenerated NF-200+RGCs and were absent from their contralateral eyes. Thus, rod-like microglia seem be related to the neurodegeneration associated with HTO.

Long-Term Potentiation in the Motor Cortex

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Iriki, Atsushi; Pavlides, Constantine; Keller, Asaf; Asanuma, Hiroshi

1989-09-01

Long-term potentiation (LTP) is a model for learning and memory processes. Tetanic stimulation of the sensory cortex produces LTP in motor cortical neurons, whereas tetanization of the ventrolateral nucleus of the thalamus, which also projects to the motor cortex, does not. However, after simultaneous high-frequency stimulation of both the sensory cortex and the ventrolateral nucleus of the thalamus, LTP of thalamic input to motor cortical neurons is induced. This associative LTP occurs only in neurons in the superficial layers of the motor cortex that receive monosynaptic input from both the sensory cortex and the ventrolateral nucleus of the thalamus. Associative LTP in the motor cortex may constitute a basis for the retention of motor skills.

Prefrontal cortex and somatosensory cortex in tactile crossmodal association: an independent component analysis of ERP recordings.

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Yixuan Ku

2007-08-01

Full Text Available Our previous studies on scalp-recorded event-related potentials (ERPs showed that somatosensory N140 evoked by a tactile vibration in working memory tasks was enhanced when human subjects expected a coming visual stimulus that had been paired with the tactile stimulus. The results suggested that such enhancement represented the cortical activities involved in tactile-visual crossmodal association. In the present study, we further hypothesized that the enhancement represented the neural activities in somatosensory and frontal cortices in the crossmodal association. By applying independent component analysis (ICA to the ERP data, we found independent components (ICs located in the medial prefrontal cortex (around the anterior cingulate cortex, ACC and the primary somatosensory cortex (SI. The activity represented by the IC in SI cortex showed enhancement in expectation of the visual stimulus. Such differential activity thus suggested the participation of SI cortex in the task-related crossmodal association. Further, the coherence analysis and the Granger causality spectral analysis of the ICs showed that SI cortex appeared to cooperate with ACC in attention and perception of the tactile stimulus in crossmodal association. The results of our study support with new evidence an important idea in cortical neurophysiology: higher cognitive operations develop from the modality-specific sensory cortices (in the present study, SI cortex that are involved in sensation and perception of various stimuli.

Intraoperative Recurrent Laryngeal Nerve Monitoring in a Patient with Contralateral Vocal Fold Palsy

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Bub-Se Na

2017-10-01

Full Text Available Recurrent laryngeal nerve injury can develop following cervical or thoracic surgery; however, few reports have described intraoperative recurrent laryngeal nerve monitoring. Consensus regarding the use of this technique during thoracic surgery is lacking. We used intraoperative recurrent laryngeal nerve monitoring in a patient with contralateral vocal cord paralysis who was scheduled for completion pneumonectomy. This case serves as an example of intraoperative recurrent laryngeal nerve monitoring during thoracic surgery and supports this indication for its use.

Periodontal status of teeth restored with crowns and its contralateral homologue, Valdivia- Chile.

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Israel Antonio Juárez; Sofía Larroulet; Makarena Ojeda; Cristian Rosas

2015-01-01

ABSTRACT Aim: To determine periodontal status of fixes single prostheses (FSP) made during the year 2013 in Austral University of Chile, and its contralateral homologue (CH).Methods: All patients with FSP made during 2013, that met the selection criteria and agreed to participate were evaluated. During the year 2014 was measured: probing depth, attachment level; bleeding on probing and dental plaque index for each FSP and CH; and consigned biological width invasion. Were measured one FSP...

Estimated risk for secondary cancer in the contra-lateral breast following radiation therapy of breast cancer

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Johansen, Safora; Danielsen, Turi; Olsen, Dag Rune

2008-01-01

Purpose. To facilitate a discussion about the impact of dose heterogeneity on the risk for secondary contralateral breast (CB) cancer predicted with linear and non linear models associated with primary breast irradiation. Methods and materials. Dose volume statistics of the CB calculated for eight patients using a collapsed cone algorithm were used to predict the excess relative risk (ERR) for cancer induction in CB. Both linear and non-linear models were employed. A sensitivity analysis demonstrating the impact of different parameter values on calculated ERR for the eight patients was also included in this study. Results. A proportionality assumption was established to make the calculations with a linear and non-linear model comparable. ERR of secondary cancer predicted by the linear model varied considerably between the patients, while the predicted ERR for the same patients using the non-linear model showed very small variation. The predicted ERRs by the two models were indistinguishable for small doses, i.e. below ∼3 Gy. The sensitivity analysis showed that the quadratic component of the radiation-induction pre-malignant cell term is negligible for lower dose level. The ERR is highly sensitive to the value of agr1 and agr2. Conclusions. Optimization of breast cancer radiation therapy, where also the risk for radiation induced secondary malignancies in the contralateral breast is taken into account, requires robust and valid risk assessment. The linear dose-risk model does not account for the complexity in the mechanisms underlying the development of secondary malignancies following exposure to radiation; this is particularly important when estimating risk associated with highly heterogeneous dose distributions as is the case in the contralateral breast of women receiving breast cancer irradiation

The Functions of the Orbitofrontal Cortex

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Rolls, Edmund T.

2004-01-01

The orbitofrontal cortex contains the secondary taste cortex, in which the reward value of taste is represented. It also contains the secondary and tertiary olfactory cortical areas, in which information about the identity and also about the reward value of odours is represented. The orbitofrontal cortex also receives information about the sight…

Cerebral cortex activation mapping upon electrical muscle stimulation by 32-channel time-domain functional near-infrared spectroscopy.

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Re, Rebecca; Muthalib, Makii; Contini, Davide; Zucchelli, Lucia; Torricelli, Alessandro; Spinelli, Lorenzo; Caffini, Matteo; Ferrari, Marco; Quaresima, Valentina; Perrey, Stephane; Kerr, Graham

2013-01-01

The application of different EMS current thresholds on muscle activates not only the muscle but also peripheral sensory axons that send proprioceptive and pain signals to the cerebral cortex. A 32-channel time-domain fNIRS instrument was employed to map regional cortical activities under varied EMS current intensities applied on the right wrist extensor muscle. Eight healthy volunteers underwent four EMS at different current thresholds based on their individual maximal tolerated intensity (MTI), i.e., 10 % < 50 % < 100 % < over 100 % MTI. Time courses of the absolute oxygenated and deoxygenated hemoglobin concentrations primarily over the bilateral sensorimotor cortical (SMC) regions were extrapolated, and cortical activation maps were determined by general linear model using the NIRS-SPM software. The stimulation-induced wrist extension paradigm significantly increased activation of the contralateral SMC region according to the EMS intensities, while the ipsilateral SMC region showed no significant changes. This could be due in part to a nociceptive response to the higher EMS current intensities and result also from increased sensorimotor integration in these cortical regions.

Perilesional and contralateral white matter evolution and integrity in patients with periventricular nodular heterotopia and epilepsy: a longitudinal diffusion tensor imaging study.

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Liu, W; Yan, B; An, D; Niu, R; Tang, Y; Tong, X; Gong, Q; Zhou, D

2017-12-01

This study aimed to assess the evolution of perinodular and contralateral white matter abnormalities in patients with periventricular nodular heterotopia (PNH) and epilepsy. Diffusion tensor imaging (DTI) (64 directions) and 3 T structural magnetic resonance imaging were performed in 29 PNH patients (mean age 27.3 years), and 16 patients underwent a second scan (average time between the two scans 1.1 years). Fractional anisotropy and mean diffusivity were measured within the perilesional and contralateral white matter. Longitudinal analysis showed that white matter located 10 mm from the focal nodule displayed characteristics intermediate to tissue 5 mm away, and normal-appearing white matter (NAWM) also established evolution profiles of perinodular white matter in different cortical lobes. Compared to 29 age- and sex-matched healthy controls, significant decreased fractional anisotropy and elevated mean diffusivity values were observed in regions 5 and 10 mm from nodules (P < 0.01), whilst DTI metrics of the remaining NAWM did not differ significantly from controls. Additionally, normal DTI metrics were shown in the contralateral region in patients with unilateral PNH. Periventricular nodular heterotopia is associated with microstructural abnormalities within the perilesional white matter and the extent decreases with increasing distance from the nodule. In the homologous contralateral region, white matter diffusion metrics were unchanged in unilateral PNH. These findings have clinical implications with respect to the medical and surgical interventions of PNH-related epilepsy. © 2017 EAN.

Experience-induced plasticity of cutaneous maps in the primary somatosensory cortex of adult monkeys and rats.

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Xerri, C; Coq, J O; Merzenich, M M; Jenkins, W M

1996-01-01

In a first study, the representations of skin surfaces of the hand in the primary somatosensory cortex, area 3b, were reconstructed in owl monkeys and squirrel monkeys trained to pick up food pellets from small, shallow wells, a task which required skilled use of the digits. Training sessions included limited manual exercise over a total period of a few hours of practice. From an early clumsy performance in which many retrieval attempts were required for each successful pellet retrieval, the monkeys exhibited a gradual improvement. Typically, the animals used various combinations of digits before developing a successful retrieval strategy. As the behavior came to be stereotyped, monkeys consistently engaged surfaces of the distal phalanges of one or two digits in the palpation and capture of food pellets from the smallest wells. Microelectrode mapping of the hand surfaces revealed that the glabrous skin of the fingertips predominantly involved in the dexterity task was represented over topographically expanded cortical sectors. Furthermore, cutaneous receptive fields which covered the most frequently stimulated digital tip surfaces were less than half as large as were those representing the corresponding surfaces of control digits. In a second series of experiments, Long-Evans rats were assigned to environments promoting differential tactile experience (standard, enriched, and impoverished) for 80 to 115 days from the time of weaning. A fourth group of young adult rat experienced a severe restriction of forepaw exploratory movement for either 7 or 15 days. Cortical maps derived in the primary somatosensory cortex showed that environmental enrichment induced a substantial enlargement of the cutaneous forepaw representation, and improved its spatial resolution (smaller glabrous receptive fields). In contrast, tactile impoverishment resulted in a degradation of the forepaw representation that was characterized by larger cutaneous receptive fields and the emergence of

TMS-induced neural noise in sensory cortex interferes with short-term memory storage in prefrontal cortex.

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Bancroft, Tyler D; Hogeveen, Jeremy; Hockley, William E; Servos, Philip

2014-01-01

In a previous study, Harris et al. (2002) found disruption of vibrotactile short-term memory after applying single-pulse transcranial magnetic stimulation (TMS) to primary somatosensory cortex (SI) early in the maintenance period, and suggested that this demonstrated a role for SI in vibrotactile memory storage. While such a role is compatible with recent suggestions that sensory cortex is the storage substrate for working memory, it stands in contrast to a relatively large body of evidence from human EEG and single-cell recording in primates that instead points to prefrontal cortex as the storage substrate for vibrotactile memory. In the present study, we use computational methods to demonstrate how Harris et al.'s results can be reproduced by TMS-induced activity in sensory cortex and subsequent feedforward interference with memory traces stored in prefrontal cortex, thereby reconciling discordant findings in the tactile memory literature.

Prevalence of Contralateral Hearing Aid Use in Adults with Cochlear Implants

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Yamaguchi, Cintia Tizue

2013-09-01

Full Text Available Introduction: The exclusive use of a cochlear implant (CI in one ear allows patients to effectively hear speech in a quiet environment. However, in environments with competing noise, the processing of multiple sounds becomes complex. In an attempt to promote binaural hearing in a noninvasive manner, the use of a hearing aid in the nonimplanted ear is suggested for patients with a unilateral CI. Aims: To identify the prevalence of hearing aid use in the contralateral ear in adults who already have a CI; to determine the reasons why some patients do not use contralateral hearing aids (CHAs; and to analyze the effects of residual hearing in CHA users. Materials and Methods: This is a clinical study in 82 adult patients with CI implants who responded to a questionnaire designed to determine current use of CHA. Results: In our patient sample, 70 CHA nonusers were identified. The prevalence of CHA users was determined to be 12% with a 95% confidence interval of 11 to 13%. About 58.2% of the CHA nonusers reported a lack of noticeable benefit even after wearing hearing aids, and 23.6% reported not having received the option to use a CHA. CHA users had a pure tone average of 107-dB hearing level, whereas CHA nonusers had a pure tone average of 117-dB hearing level. Conclusion: The prevalence of the use of a CHA is low in our study. We attribute the low use of a CHA to either a lack of residual hearing or to a lack of benefit from the amplification.

Cytoarchitectonical analysis and probabilistic mapping of two extrastriate areas of the human posterior fusiform gyrus.

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Caspers, Julian; Zilles, Karl; Eickhoff, Simon B; Schleicher, Axel; Mohlberg, Hartmut; Amunts, Katrin

2013-03-01

The human extrastriate visual cortex comprises numerous functionally defined areas, which are not identified in the widely used cytoarchitectonical map of Brodmann. The ventral part of the extrastriate cortex is particularly devoted to the identification of visual objects, faces and word forms. We analyzed the region immediately antero-lateral to hOc4v in serially sectioned (20 μm) and cell body-stained human brains using a quantitative observer-independent cytoarchitectonical approach to further identify the anatomical organization of the extrastriate cortex. Two novel cytoarchitectonical areas, FG1 and FG2, were identified on the posterior fusiform gyrus. The results of ten postmortem brains were then registered to their MRI volumes (acquired before histological processing), 3D reconstructed, and spatially normalized to the Montreal Neurological Institute reference brain. Finally, probabilistic maps were generated for each cytoarchitectonical area by superimposing the areas of the individual brains in the reference space. Comparison with recent functional imaging studies yielded that both areas are located within the object-related visual cortex. FG1 fills the gap between the retinotopically mapped area VO-1 and a posterior fusiform face patch. FG2 is probably the correlate of this face patch.

Anticipation increases tactile stimulus processing in the ipsilateral primary somatosensory cortex.

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van Ede, Freek; de Lange, Floris P; Maris, Eric

2014-10-01

Stimulus anticipation improves perception. To account for this improvement, we investigated how stimulus processing is altered by anticipation. In contrast to a large body of previous work, we employed a demanding perceptual task and investigated sensory responses that occur beyond early evoked activity in contralateral primary sensory areas: Stimulus-induced modulations of neural oscillations. For this, we recorded magnetoencephalography in 19 humans while they performed a cued tactile identification task involving the identification of either a proximal or a distal stimulation on the fingertips. We varied the cue-target interval between 0 and 1000 ms such that tactile targets occurred at various degrees of anticipation. This allowed us to investigate the influence of anticipation on stimulus processing in a parametric fashion. We observed that anticipation increases the stimulus-induced response (suppression of beta-band oscillations) originating from the ipsilateral primary somatosensory cortex. This occurs in the period in which the tactile memory trace is analyzed and is correlated with the anticipation-induced improvement in tactile perception. We propose that this ipsilateral response indicates distributed processing across bilateral primary sensory cortices, of which the extent increases with anticipation. This constitutes a new and potentially important mechanism contributing to perception and its improvement following anticipation. © The Author 2013. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Patterns of Occurrence and Outcomes of Contralateral Breast Cancer: Analysis of SEER Data

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Zhenchong Xiong

2018-05-01

Full Text Available Population-based estimates are lacking for the temporal trends in the contralateral breast cancer (CBC risk for patients with breast cancer (BC. Data for BC patients diagnosed with CBC were collected from the Surveillance, Epidemiology, and End Results database. CBC incidence was calculated using the Kaplan-Meier method and the temporal trend in CBC incidence was assessed using joinpoint regression. Survival analysis was calculated using propensity scoring (PS and multivariate Cox regression with a competing risk model. We found that 10,944 of 212,630 patients with early-stage BC were subsequently diagnosed with secondary BC in the contralateral breast. The 5-, 10-, 15-, and 20-year cumulative CBC incidences were 1.9, 4.6, 7.6, and 10.5%, respectively. Being younger (<40 years, black, hormone receptor-negative, and having undergone radiotherapy were correlated with a high risk of CBC occurrence. CBC incidence increased continuously in the first 11 years after the initial cancer diagnosis, and the upward trend slowed from years 11 to 21, and tended to decline from years 21 to 24. CBC diagnosis was significantly and negatively associated with survival. We reported population-based estimates of the CBC occurrence pattern and risk factors. Patients are at high risk of developing CBC in the first 21 years after the initial BC diagnosis.

Seeing touch in the somatosensory cortex: a TMS study of the visual perception of touch.

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Bolognini, Nadia; Rossetti, Angela; Maravita, Angelo; Miniussi, Carlo

2011-12-01

Recent studies suggest the existence of a visuo-tactile mirror system, comprising the primary (SI) and secondary (SII) somatosensory cortices, which matches observed touch with felt touch. Here, repetitive transcranial magnetic stimulation (rTMS) was used to determine whether SI or SII play a functional role in the visual processing of tactile events. Healthy participants performed a visual discrimination task with tactile stimuli (a finger touching a hand) and a control task (a finger moving without touching). During both tasks, rTMS was applied over either SI or SII, and to the occipital cortex. rTMS over SI selectively reduced subject performance for interpreting whether a contralateral visual tactile stimulus contains a tactile event, whereas SII stimulation impaired visual processing regardless of the tactile component. These findings provide evidence for a multimodal sensory-motor system with mirror properties, where somatic and visual properties of action converge. SI, a cortical area traditionally viewed as modality-specific, is selectively implicated in the visual processing of touch. These results are in line with the existence of a sensory mirror system mediating the embodied simulation concept. Copyright © 2010 Wiley Periodicals, Inc.

Chronic motor cortex stimulation in patients with advanced Parkinson's disease and effects on striatal dopaminergic transmission as assessed by 123I-FP-CIT SPECT: a preliminary report.

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Di Giuda, Daniela; Calcagni, Maria L; Totaro, Manuela; Cocciolillo, Fabrizio; Piano, Carla; Soleti, Francesco; Fasano, Alfonso; Cioni, Beatrice; Bentivoglio, Anna R; Giordano, Alessandro

2012-09-01

The objective of this study was to assess striatal dopamine transporter availability in patients with advanced Parkinson's disease (PD) before and after 13 months of unilateral extradural motor cortex stimulation (EMCS) with [123I]N-ω-fluoropropyl-2-β-carbo-methoxy-3-β-(4-iodophenyl)nortropane single photon emission computed tomography (123I-FP-CIT SPECT). Six PD patients (five women and one man, aged 63.2 ± 5.6 years) underwent 123I-FP-CIT SPECT and clinical evaluation [Unified Parkinson's Disease Rating Scale (UPDRS) and Parkinson's Disease Quality of Life Scale (PDQL)] preoperatively, 8 and 13 months after EMCS. Striatum-to-occipital cortex, caudate-to-occipital cortex and putamen-to-occipital cortex 123I-FP-CIT uptake ratios were calculated using the region of interest method. Total and part III UPDRS scores significantly decreased at 8 and 13 months after stimulation (P=0.02 and 0.04, respectively); UPDRS part II and PDQL scores improved after 13 months (P=0.02 and 0.04, respectively). No significant differences in 123I-FP-CIT uptake ratios between baseline and follow-up were found in the examined regions. However, a progressive reduction in 123I-FP-CIT uptake ratios in the striatum contralateral to the implant was found. In contrast, no further decrease in 123I-FP-CIT uptake ratios was detected in the striatum ipsilateral to the implant. There were no correlations between changes in 123I-FP-CIT uptake ratios with disease duration, changes in medication dosage and motor UPDRS scores. Despite a small but highly selected sample of advanced PD patients, our results showed that no further dopamine transporter reduction occurred in the striatum ipsilateral to the implant side. This finding could lead to the hypothesis that EMCS might elicit a 'neuroprotective' effect, as suggested by significant clinical benefits.

fMRI Evidence of Acupoints Specificity in Two Adjacent Acupoints

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Hua Liu

2013-01-01

Full Text Available Objectives. Acupoint specificity is the foundation of acupuncture treatment. The aim of this study is to investigate whether the acupoint specificity exists in two adjacent acupoints. Design and Setting. Two adjacent real acupoints, LR3 (Taichong and ST44 (Neiting, and a nearby nonacupoint were selected. Thirty-three health volunteers were divided into three groups in random order, and each group only received acupuncture at one of the three points. While they received acupuncture, fMRI scan was performed. Results. The common cerebral activated areas responding to LR3 and ST44 included the contralateral primary somatosensory area (SI and ipsilateral cerebellum. Acupuncture at LR3 specifically activated contralateral middle occipital gyrus, ipsilateral medial frontal gyrus, superior parietal lobe, middle temporal gyrus, rostral anterior cingulate cortex (rACC, lentiform nucleus, insula, and contralateral thalamus. Stimulation at ST44 selectively activated ipsilateral secondary somatosensory area (SII, contralateral middle frontal gyrus, inferior frontal gyrus, lingual gyrus, lentiform nucleus, and bilateral posterior cingulate cortex (PCC. Conclusions. Acupuncture at adjacent acupoints elicits distinct cerebral activation patterns, and those specific patterns might be involved in the mechanism of the specific therapeutic effects of different acupoints.

Intravaginal testicular torsion in newborns. To fix or not to fix the contralateral testis?

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G. Bordin

2013-10-01

Full Text Available Scrotal swelling suggesting testicular torsion is a rare urological emergency which requires a clinical urgent evaluation and most of the times must be managed surgically. In newborns it can occur in the postnatal period, usually within the twenty-eighth day of life, or more frequently in utero, during the descent of the testis into the scrotum. Usually its poor fixedness allows the testis an abnormal mobility inside the scrotum, configuring the framework of extravaginal torsion. On the contrary during the perinatal period a twist that takes place inside the tunica vaginalis, known as intravaginal torsion, is extremely uncommon and only few cases are well documented in the literature. Authors present a rare case of intravaginal testicular torsion occurred in perinatal period. In this situation only the early surgical exploration of the scrotum may allow the rescue of the gonad, although in rare cases. Timing of surgical treatment and need for contralateral testicular fixation remain controversial. However since the anatomical defect of the tunica vaginalis can be bilateral the surgical fixation even of the contralateral testis is important, now or later, in order to prevent any future torsion of this gonad. The authors also present a brief review of recent literature on the subject.

Metastasis of Ciliary Body Melanoma to the Contralateral Eye: A Case Report and Review of Uveal Melanoma Literature

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Nouritza M. Torossian

2015-01-01

Full Text Available Many types of cancers metastasize to the eye. However, uveal melanoma metastasizing to the contralateral choroid is very rare. We report the case of a 68-year-old man with history of treated uveal melanoma of the right eye that developed metastasis to the liver and the choroid of the left eye. Ten years earlier, he was diagnosed to have uveal melanoma of the right eye and was initially treated with plaque radiotherapy. Two years later, upon progression of the disease in the right eye he had enucleation of the eye. We describe the patient’s clinical history, the diagnosis of recurrent disease in the contralateral eye, therapy of the left eye, and systemic metastasis. In addition, we reviewed the published medical literature and described the recent advances in the management of uveal melanoma.

Visual Categorization and the Parietal Cortex

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Jamie K Fitzgerald

2012-05-01

Full Text Available The primate brain is adept at rapidly grouping items and events into functional classes, or categories, in order to recognize the significance of stimuli and guide behavior. Higher cognitive functions have traditionally been considered the domain of frontal areas. However, increasing evidence suggests that parietal cortex is also involved in categorical and associative processes. Previous work showed that the parietal cortex is highly involved in spatial processing, attention and saccadic eye movement planning, and more recent studies have found decision-making signals in LIP. We recently found that a subdivision of parietal cortex, the lateral intraparietal area (LIP, reflects learned categories for multiple types of visual stimuli. Additionally, a comparison of categorization signals in parietal and frontal areas found stronger and earlier categorization signals in parietal cortex, arguing that parietal abstract association or category signals are unlikely to arise via feedback from prefrontal cortex (PFC.

Radiation induced cancer risk estimation for contralateral breast in 3D conformal treatments of post mastectomy cancer patients: based on OED

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Hemalatha, A.; Athiyaman, M.; Kumar, H.S.; Chougule, Arun

2016-01-01

A global comparison of breast cancer in India with other countries like US/China in 2012 gave a data that collectively the above countries including India account for almost one third of global breast cancer burden. According to this report for every two women newly diagnosed with breast cancer in India, one lady is dying of it. The curative radiotherapy for breast cancer treatment associated with scattered and leakage radiation exposure to critical organs like contralateral breast, lung etc. Radiation is one of the well known carcinogen of breast due its high radiosensititvity. The study done by Stovall et al concluded that the contralateral breast cancer risk is elevated for breast cancer patients of age less than 40 years if dose to health breast is greater than 1 Gy. So its necessary to evaluate dose to Contralateral Breast (ClB) for breast cancer patients for more than 1 Gy. The aim of this study is to compare the risks of secondary breast cancer from conventional wedge field and forward IMRT technique using the concept of OED-Organ Equivalent Dose/for chest wall irradiation of post mastectomy breast cancer patients

Occipital cortex of blind individuals is functionally coupled with executive control areas of frontal cortex.

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Deen, Ben; Saxe, Rebecca; Bedny, Marina

2015-08-01

In congenital blindness, the occipital cortex responds to a range of nonvisual inputs, including tactile, auditory, and linguistic stimuli. Are these changes in functional responses to stimuli accompanied by altered interactions with nonvisual functional networks? To answer this question, we introduce a data-driven method that searches across cortex for functional connectivity differences across groups. Replicating prior work, we find increased fronto-occipital functional connectivity in congenitally blind relative to blindfolded sighted participants. We demonstrate that this heightened connectivity extends over most of occipital cortex but is specific to a subset of regions in the inferior, dorsal, and medial frontal lobe. To assess the functional profile of these frontal areas, we used an n-back working memory task and a sentence comprehension task. We find that, among prefrontal areas with overconnectivity to occipital cortex, one left inferior frontal region responds to language over music. By contrast, the majority of these regions responded to working memory load but not language. These results suggest that in blindness occipital cortex interacts more with working memory systems and raise new questions about the function and mechanism of occipital plasticity.

Laparoscopic adrenal cortex

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Peyrolou, A.; Salom, A.; Harguindeguy; Taroco, L.; Ardao, G.; Broli, F. . E mail: andresssss@adinet.com.uy

2005-01-01

The paper presents the case of a female patient who carried an aldosterone-secreting tumor of adrenal cortex.In the analysis of diagnosis and para clinical examinations there is particular reference to the laparoscopic surgery mode of treatment.Diagnosis should be established on the basis of clinical and laboratory tests (hypopotassemia and hyperaldosteronism).Tumor topography was confirmed through CT scan, MRI and Scintiscan in left adrenal cortex.Resection was consequently made through laparoscopic surgery.The patients evolution was excellent from the surgical viewpoint,with I levels of blood pressure, potassium and aldosterone returned to normal

Esophagus and contralateral lung-sparing IMRT for locally advanced lung cancer in the community hospital setting

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Johnny eKao

2015-06-01

Full Text Available Background: The optimal technique for performing lung IMRT remains poorly defined. We hypothesize that improved dose distributions associated with normal tissue sparing IMRT can allow for safe dose escalation resulting in decreased acute and late toxicity. Methods: We performed a retrospective analysis of 82 consecutive lung cancer patients treated with curative intent from 1/10 to 9/14. From 1/10 to 4/12, 44 patients were treated with the community standard of 3-dimensional conformal radiotherapy or IMRT without specific esophagus or contralateral lung constraints (standard RT. From 5/12 to 9/14, 38 patients were treated with normal tissue-sparing IMRT with selective sparing of contralateral lung and esophagus. The study endpoints were dosimetry, toxicity and overall survival.Results: Despite higher mean prescribed radiation doses in the normal tissue-sparing IMRT cohort (64.5 Gy vs. 60.8 Gy, p=0.04, patients treated with normal tissue-sparing IMRT had significantly lower lung V20, V10, V5, mean lung, maximum esophagus and mean esophagus doses compared to patients treated with standard RT (p≤0.001. Patients in the normal tissue-sparing IMRT group had reduced acute grade ≥3 esophagitis (0% vs. 11%, p<0.001, acute grade ≥2 weight loss (2% vs. 16%, p=0.04, late grade ≥2 pneumonitis (7% vs. 21%, p=0.02. The 2-year overall survival was 52% with normal tissue-sparing IMRT arm compared to 28% for standard RT (p=0.015.Conclusion: These data provide proof of principle that suboptimal radiation dose distributions are associated with significant acute and late lung and esophageal toxicity that may result in hospitalization or even premature mortality. Strict attention to contralateral lung and esophageal dose volume constraints are feasible in the community hospital setting without sacrificing disease control.

Contralateral regional recurrence after elective unilateral neck irradiation in oropharyngeal carcinoma: A literature-based critical review.

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Al-Mamgani, Abrahim; van Werkhoven, Erik; Navran, Arash; Karakullukcu, Baris; Hamming-Vrieze, Olga; Machiels, Melanie; van der Velden, Lilly-Ann; Vogel, Wouter V; Klop, W Martin

2017-09-01

The head and neck region has rich regional lymphatic network, with a theoretical risk on contralateral metastasis from oropharyngeal cancer (OPC). There is a long-standing convention to irradiate the great majority of these tumors electively to both sides of the neck to reduce the risk of contralateral regional failure (cRF), but this can induce significant toxicity. We aimed to identify patient groups where elective contralateral irradiation may safely be omitted. PubMed and EMBASE were searched for original full-text articles in English with a combination of search terms related to the end points: cRF in OPC primarily treated by radiotherapy only to the ipsilateral neck and identifying predictive factors for increased incidence of cRF. The data from the identified studies were pooled, the incidence of cRF was calculated and the correlation with different predictive factors was investigated. Eleven full-text articles met the inclusion criteria. In these studies, 1116 patients were treated to the ipsilateral neck alone. The mean incidence of cRF was 2.42% (range 0-5.9%, 95% CI 1.6-3.5%). The incidence of cRF correlated only with T-stage (p=0.008), and involvement of midline (p=0.001). However, the significant correlation with T-stage can be explained by the very low incidence of cRF among T1 (0.77%), and disappeared when the incidence of cRF was compared between T2, T3,and T4 (p=0.344). The incidence of cRF in patients with OPC is very low, with involvement of midline providing the most significant prognosticator. These results call for trials on unilateral elective irradiation in selected groups. Copyright © 2017 Elsevier Ltd. All rights reserved.

[Amaurosis and contralateral cranial nerve pairs III and VI paralysis after peribulbar block - Case report].

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Leme, Fábio Caetano Oliveira; Moro, Eduardo Toshiyuki; Ferraz, Alexandre Alberto Fontana

2016-08-20

Peribulbar anesthesia (PBA) has emerged as a safer option compared with intraconal retrobulbar block. Still, PBA may not be considered without risk. Numerous complications have been described when performing this technique. This report aims to describe a rare case of amaurosis and contralateral paralysis while attempting to perform a PBA. Male patient, 75-year old, physical status ASA II, undergoing cataract surgery by phacoemulsification with intraocular lens implantation. Sedated with fentanyl and midazolam and subjected to PBA. There were no complications during surgery. After finishing the procedure, the patient reported lack of vision in the contralateral eye. Akinesia of the muscles innervated by the cranial nerve pairs III and VI, ptosis, and medium-sized pupils unresponsive to light stimulus were observed. Four hours after anesthesia, complete recovery of vision and eyelid and eyeball movements was seen in the non-operated eye. During PBA, structures located in the intraconal space can be accidentally hit leading to complications such as described in the above report. Following the technical guidelines and using appropriate size needles may reduce the risk of such complication, but not completely. Copyright © 2016. Publicado por Elsevier Editora Ltda.

Acute L5 pedicle fracture and contralateral spondylolysis in a 12-year-old boy: a case report

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Mary, Pierre; de Carvalho, Antonio; Pointe, Hubert Ducou le; Damsin, Jean-Paul; Filipe, Georges

2007-01-01

Acute unilateral L5 pedicle fracture associated with a pre-existing contralateral spondylolysis is a rare lesion. We report a case in a non-competitive 12-year-old boy. We present the clinical, radiological and specific management of this rare condition. The clinical and radiological draft of this patient was reviewed. The follow-up was 30 months after fracture healing. Some cases reported in the literature were analyzed and our clinical findings and therapeutic strategy was compared and discussed. Non-operative treatment was done including full-time bracing in a modified Boston brace incorporating one thigh for 3 months. Plain radiographs and computed tomographic (CT)-scan performed at 3 and 6 months showed progressive healing of the pedicle fracture and no modification of the contralateral isthmic spondylolytic lesion. At final follow-up, the patient was asymptomatic and resumed all his activities. In skeletally immature patients, we think that conservative treatment should be considered as a treatment option for this unusual injury. PMID:17520295

Bilateral implantation of +2.5 D multifocal intraocular lens and contralateral implantation of +2.5 D and +3.0 D multifocal intraocular lenses: Clinical outcomes.

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Nuijts, Rudy M M A; Jonker, Soraya M R; Kaufer, Robert A; Lapid-Gortzak, Ruth; Mendicute, Javier; Martinez, Cristina Peris; Schmickler, Stefanie; Kohnen, Thomas

2016-02-01

To assess the clinical visual outcomes of bilateral implantation of Restor +2.5 diopter (D) multifocal intraocular lenses (IOLs) and contralateral implantation of a Restor +2.5 D multifocal IOL in the dominant eye and Restor +3.0 D multifocal IOL in the fellow eye. Multicenter study at 8 investigative sites. Prospective randomized parallel-group patient-masked 2-arm study. This study comprised adults requiring bilateral cataract extraction followed by multifocal IOL implantation. The primary endpoint was corrected intermediate visual acuity (CIVA) at 60 cm, and the secondary endpoint was corrected near visual acuity (CNVA) at 40 cm. Both endpoints were measured 3 months after implantation with a noninferiority margin of Δ = 0.1 logMAR. In total, 103 patients completed the study (53 bilateral, 50 contralateral). At 3 months, the mean CIVA at 60 cm was 0.13 logMAR and 0.10 logMAR in the bilateral group and contralateral group, respectively (difference 0.04 logMAR), achieving noninferiority. Noninferiority was not attained for CNVA at 40 cm; mean values at 3 months for bilateral and contralateral implantation were 0.26 logMAR and 0.11 logMAR, respectively (difference 0.15 logMAR). Binocular defocus curves suggested similar performance in distance vision between the 2 groups. Treatment-emergent ocular adverse events rates were similar between the groups. Bilateral implantation of the +2.5 D multifocal IOL resulted in similar distance as contralateral implantation of the +2.5 D multifocal IOL and +3.0 D multifocal IOL for intermediate vision (60 cm), while noninferiority was not achieved for near distances (40 cm). Copyright © 2016 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Cortical inhibition effect in musicians and non-musicians using P300 with and without contralateral stimulation

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Camila Maia Rabelo

2015-02-01

Full Text Available Introduction: Musicians have more robust and efficient neural responses in the cortical and sub-cortical regions, demonstrating that musical experience benefits the processing of both non-linguistic and linguistic stimuli. Objective: This study aimed to verify P300's latency and amplitude behavioral using contralateral stimulation in musicians and non-musicians. Methods: This was a case-control study. Subjects were divided in two groups: musicians, comprising 30 professional musicians, and non-musicians, comprising 25 subjects without musical experience. Results: The present study showed that the musicians had lower latencies and higher amplitudes than the non-musicians in the P300 without contralateral noise. For the P300 amplitude values, the difference between groups persisted, and the musicians presented significantly higher amplitude values compared with the non-musicians; additionally, the analysis of the noise effect on the P300 response showed that the latency values were significantly increased in the musicians. Conclusion: The central auditory nervous system of musicians presents peculiar characteristics of electrophysiological responses probably due to the plasticity imposed by musical practice.

LIN7A depletion disrupts cerebral cortex development, contributing to intellectual disability in 12q21-deletion syndrome.

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Ayumi Matsumoto

Full Text Available Interstitial deletion of 12q21 has been reported in four cases, which share several common clinical features, including intellectual disability (ID, low-set ears, and minor cardiac abnormalities. Comparative genomic hybridization (CGH analysis using the Agilent Human Genome CGH 180K array was performed with the genomic DNA from a two-year-old Japanese boy with these symptoms, as well as hypoplasia of the corpus callosum. Consequently, a 14 Mb deletion at 12q21.2-q21.33 (nt. 77 203 574-91 264 613 bp, which includes 72 genes, was detected. Of these, we focused on LIN7A, which encodes a scaffold protein that is important for synaptic function, as a possible responsible gene for ID, and we analyzed its role in cerebral cortex development. Western blotting analyses revealed that Lin-7A is expressed on embryonic day (E 13.5, and gradually increases in the mouse brain during the embryonic stage. Biochemical fractionation resulted in the enrichment of Lin-7A in the presynaptic fraction. Suppression of Lin-7A expression by RNAi, using in utero electroporation on E14.5, delayed neuronal migration on postnatal day (P 2, and Lin-7A-deficient neurons remained in the lower zone of the cortical plate and the intermediate zone. In addition, when Lin-7A was silenced in cortical neurons in one hemisphere, axonal growth in the contralateral hemisphere was delayed; development of these neurons was disrupted such that one half did not extend into the contralateral hemisphere after leaving the corpus callosum. Taken together, LIN7A is a candidate gene responsible for 12q21-deletion syndrome, and abnormal neuronal migration and interhemispheric axon development may contribute to ID and corpus callosum hypoplasia, respectively.

Adjuvant radiotherapy and risk of contralateral breast cancer

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Storm, H.H.; Blettner, M.; Pedersen, J.

1992-01-01

To evaluate the relationship between high-dose radiotherapy and secondary breast cancer, a nested and matched case-control study in the cohort of breast cancer patients in Denmark was conducted. Radiation dose to the contralateral breast was reconstructed by medical physicists for each of the 529 cases and 529 controls, 82.4% of each group was treated with radiation. The average breast dose was 2.51 Gy, and a 20% increased risk was expected for this population at average age 51 years. There was no evidence that radiotherapy increased the overall risk of second breast cancer (RR=1.04), although the possibility of a RR as high as 1.46 could not be excluded. There was little indication that the risk varied over categories of radiation dose, time since exposure, or age at exposure. Thus, data provides additional evidence that there is little if any risk of radiation induced breast cancer associated with exposure of breast tissue to low-dose radiation (e.g., from mammographic X-rays or adjuvant radiotherapy) in later life. (author). 9 refs., 1 fig., 1 tab

Interhemispheric claustral circuits coordinate somatomotor and visuomotor cortical areas that regulate exploratory behaviors

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Jared Brent Smith

2014-05-01

Full Text Available The claustrum has a role in the interhemispheric transfer of certain types of sensorimotor information. Whereas the whisker region in rat motor (M1 cortex sends dense projections to the contralateral claustrum, the M1 forelimb representation does not. The claustrum sends strong ipsilateral projections to the whisker regions in M1 and somatosensory (S1 cortex, but its projections to the forelimb cortical areas are weak. These distinctions suggest that one function of the M1 projections to the contralateral claustrum is to coordinate the cortical areas that regulate peripheral sensor movements during behaviors that depend on bilateral sensory acquisition. If this hypothesis is true, then similar interhemispheric circuits should interconnect the frontal eye fields (FEF with the contralateral claustrum and its network of projections to vision-related cortical areas. To test this hypothesis, anterograde and retrograde tracers were placed in physiologically-defined parts of the FEF and primary visual cortex (V1 in rats. We observed dense FEF projections to the contralateral claustrum that terminated in the midst of claustral neurons that project to both FEF and V1. While the FEF inputs to the claustrum come predominantly from the contralateral hemisphere, the claustral projections to FEF and V1 are primarily ipsilateral. Detailed comparison of the present results with our previous studies on somatomotor claustral circuitry revealed a well-defined functional topography in which the ventral claustrum is connected with visuomotor cortical areas and the dorsal regions are connected with somatomotor areas. These results suggest that subregions within the claustrum play a critical role in coordinating the cortical areas that regulate the acquisition of modality-specific sensory information during exploration and other behaviors that require sensory attention.

Significance of X-ray examination in the diagnosis of contralateral pneumonia in closed chest trauma

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Anan'ina, G.V.; Parizhskij, Z.M.; Abramova, T.T.

1986-01-01

It is shown that after unilateral closed chest traumas X-ray examination of both lungs should be conducted to except traumatic pneumonia as at the side of the trauma as in contralateral lung and to exclude pneumonia complications. Special attention must be paid to the patients with traumatic rib fractures and to those who has chromic nonspecific diseases of lungs and abused with alcochol

Mapping of functional activity in brain with 18F-fluoro-deoxyglucose

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Alavi, A.; Reivich, M.; Greenberg, J.

1981-01-01

The efficacy of using the 18 F-fluoro-deoxyglucose ( 18 F-DG) for measuring regional cerebral glucose utilization in man during functional activation is demonstrated. Normal male volunteers subjected to sensory stimuli (visual, auditory, tactile) exhibited focal increases in glucose metabolism in response to the stimulus. Unilateral visual hemifield stimulation caused the contralateral striate cortex to become more active metabolically than the striate cortex ipsilateral to the stimulated hemifield. Similarly, stroking of the fingers and hand of one arm with a brush produced an increase in metabolism in the contralateral postcentral gyrus compared to the homologous ipsilateral region. The auditory stimulus, which consisted of monaural listening to either a meaningful or nonmeaningful story, caused an increase in glucose metabolism in the right temporal cortex independent of which ear was stimulated. These results demonstrate that the 18 F-DG technique is capable of providing functional maps in vivo in the human brain

Computer-aided detection system performance on current and previous digital mammograms in patients with contralateral metachronous breast cancer

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Kim, Seung Ja; Moon, Woo Kyung; Cho, Nariya; Chang, Jung Min

2012-01-01

Background: The computer-aided detection (CAD) system is widely used for screening mammography. The performance of the CAD system for contralateral breast cancer has not been reported for women with a history of breast cancer. Purpose: To retrospectively evaluate the performance of a CAD system on current and previous mammograms in patients with contralateral metachronous breast cancer. Material and Methods: During a 3-year period, 4945 postoperative patients had follow-up examinations, from whom we selected 55 women with contralateral breast cancers. Among them, 38 had visible malignant signs on the current mammograms. We analyzed the sensitivity and false-positive marks of the system on the current and previous mammograms according to lesion type and breast density. Results: The total visible lesion components on the current mammograms included 27 masses and 14 calcifications in 38 patients. The case-based sensitivity for all lesion types was 63.2% (24/38) with false-positive marks of 0.71 per patient. The lesion-based sensitivity for masses and calcifications was 59.3% (16/27) and 71.4% (10/14), respectively. The lesion-based sensitivity for masses in fatty and dense breasts was 68.8% (11/16) and 45.5% (5/11), respectively. The lesion-based sensitivity for calcifications in fatty and dense breasts was 100.0% (3/3) and 63.6% (7/11), respectively. The total visible lesion components on the previous mammograms included 13 masses and three calcifications in 16 patients, and the sensitivity for all lesion types was 31.3% (5/16) with false-positive marks of 0.81 per patient. On these mammograms, the sensitivity for masses and calcifications was 30.8% (4/13) and 33.3% (1/3), respectively. The sensitivity in fatty and dense breasts was 28.6% (2/7) and 33.3% (3/9), respectively. Conclusion: In the women with a history of breast cancer, the sensitivity of the CAD system in visible contralateral breast cancer was lower than in most previous reports using the same CAD

Misconceptions about mirror-induced motor cortex activation.

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Praamstra, P.; Torney, L.; Rawle, C.J.; Miall, R.C.

2011-01-01

Observation of self-produced hand movements through a mirror, creating an illusion of the opposite hand moving, was recently reported to induce ipsilateral motor cortex activation, that is, motor cortex activation for the hand in rest. The reported work goes far beyond earlier work on motor cortex

Motor Improvement of Skilled Forelimb Use Induced by Treatment with Growth Hormone and Rehabilitation Is Dependent on the Onset of the Treatment after Cortical Ablation

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Margarita Heredia

2018-01-01

Full Text Available We previously demonstrated that the administration of GH immediately after severe motor cortex injury, in rats, followed by rehabilitation, improved the functionality of the affected limb and reexpressed nestin in the contralateral motor cortex. Here, we analyze whether these GH effects depend on a time window after the injury and on the reexpression of nestin and actin. Injured animals were treated with GH (0.15 mg/kg/day or vehicle, at days 7, 14, and 35 after cortical ablation. Rehabilitation was applied at short and long term (LTR after the lesion and then sacrificed. Nestin and actin were analyzed by immunoblotting in the contralateral motor cortex. Giving GH at days 7 or 35 after the lesion, but not 14 days after it, led to a remarkable improvement in the functionality of the affected paw. Contralateral nestin and actin reexpression was clearly higher in GH-treated animals, probably because compensatory brain plasticity was established. GH and immediate rehabilitation are key for repairing brain injuries, with the exception of a critical time period: GH treatment starting 14 days after the lesion. Our data also indicate that there is not a clear plateau in the recovery from a brain injury in agreement with our data in human patients.

Word Recognition in Auditory Cortex

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DeWitt, Iain D. J.

2013-01-01

Although spoken word recognition is more fundamental to human communication than text recognition, knowledge of word-processing in auditory cortex is comparatively impoverished. This dissertation synthesizes current models of auditory cortex, models of cortical pattern recognition, models of single-word reading, results in phonetics and results in…

Maps of the Auditory Cortex.

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Brewer, Alyssa A; Barton, Brian

2016-07-08

One of the fundamental properties of the mammalian brain is that sensory regions of cortex are formed of multiple, functionally specialized cortical field maps (CFMs). Each CFM comprises two orthogonal topographical representations, reflecting two essential aspects of sensory space. In auditory cortex, auditory field maps (AFMs) are defined by the combination of tonotopic gradients, representing the spectral aspects of sound (i.e., tones), with orthogonal periodotopic gradients, representing the temporal aspects of sound (i.e., period or temporal envelope). Converging evidence from cytoarchitectural and neuroimaging measurements underlies the definition of 11 AFMs across core and belt regions of human auditory cortex, with likely homology to those of macaque. On a macrostructural level, AFMs are grouped into cloverleaf clusters, an organizational structure also seen in visual cortex. Future research can now use these AFMs to investigate specific stages of auditory processing, key for understanding behaviors such as speech perception and multimodal sensory integration.

Cellular properties of principal neurons in the rat entorhinal cortex. I. The lateral entorhinal cortex

NARCIS (Netherlands)

Canto, C.B.; Witter, M.P.

2012-01-01

The lateral entorhinal cortex (LEC) provides a major cortical input to the hippocampal formation, equaling that of the medial entorhinal cortex (MEC). To understand the functional contributions made by LEC, basic knowledge of individual neurons, in the context of the intrinsic network, is needed.

Transcranial magnetic stimulation of the dorsal lateral prefrontal cortex inhibits medial orbitofrontal activity in smokers.

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Li, Xingbao; Sahlem, Gregory L; Badran, Bashar W; McTeague, Lisa M; Hanlon, Colleen A; Hartwell, Karen J; Henderson, Scott; George, Mark S

2017-12-01

Several studies have shown that repetitive transcranial magnetic stimulation (rTMS), applied to the dorsolateral prefrontal cortex (DLPFC), can reduce cue-elicited craving in smokers. Currently, the mechanism of this effect is unknown. We used functional magnetic resonance imaging (fMRI) to explore the effect of a single treatment of rTMS on cortical and sub-cortical neural activity in non-treatment seeking nicotine-dependent participants. We conducted a randomized, counterbalanced, crossover trial in which participants attended two experimental visits separated by at least 1 week. On the first visit, participants received either active, or sham rTMS (10 Hz, 5 s-on, 10 s-off, 100% motor threshold, 3,000 pulses) over the left DLPFC, and on the second visit they received the opposite condition (active or sham). Cue craving fMRI scans were completed before and after each rTMS session. A total of 11 non-treatment seeking nicotine-dependent cigarette smokers were enrolled in the study [six female, average age 39.7 ± 13.2, average cigarettes per day 17.3 ± 5.9]. Active rTMS decreased activity in the contralateral medial orbitofrontal cortex (mOFC) and ipsilateral nucleus accumbens (NAc) compared to sham rTMS. This preliminary data suggests that one session of rTMS applied to the DLPFC decreases brain activity in the NAc and mOFC in smokers. rTMS may exert its anti-craving effect by decreasing activity in the NAc and mOFC in smokers. Despite a small sample size, these findings warrant future rTMS/fMRI studies in addictions. (Am J Addict 2017;26:788-794). © 2017 American Academy of Addiction Psychiatry.

Reduced GABAA receptor density contralateral to a potentially epileptogenic MRI abnormality in a patient with complex partial seizures

International Nuclear Information System (INIS)

Kuwert, T.; Stodieck, S.R.G.; Puskas, C.; Diehl, B.; Puskas, Z.; Schuierer, G.; Vollet, B.; Schober, O.

1996-01-01

Imaging cerebral GABA A receptor density (GRD) with single-photon emission tomography (SPET) and iodine-123 iomazenil is highly accurate in lateralizing epileptogenic foci in patients with complex partial seizures of temporal origin. Limited knowledge exists on how iomazenil SPET compares with magnetic resonance imaging (MRI) in this regard. We present a patient with complex partial seizures in whom MRI had identified an arachnoid cyst anterior to the tip of the left temporal lobe. Contralaterally to this structural abnormality, interictal electroencephalography (EEG) performed after sleep deprivation disclosed an intermittent frontotemporal dysrhythmic focus with slow and sharp waves. On iomazenil SPET images GRD was significantly reduced in the right temporal lobe and thus contralaterally to the MRI abnormality, but ipsilaterally to the pathological EEG findings. These data suggest that iomazenil SPET may significantly contribute to the presurgical evaluation of epileptic patients even when MRI identifies potentialy epileptogenic structural lesions. (orig.)

Assessment of contralateral breast dose reduction in post mastectomy patients using superflab during EBRT

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Akanksha, S.; Athiyaman, M.; Hemalatha, A.; Kumar, H.S.

2016-01-01

Breast cancer (BC) is most common cancer in women worldwide. External beam radiotherapy (EBRT) is used as adjuvant in most post operative BC cases for loco-regional control. Present study is concerned about dose received by contralateral breast (CLB) during EBRT which results due to scatter from treatment head. Dose to CLB in 18 post operative BC patients were evaluated using CaSO_4-Dy thermoluminiscence dosimeters (TLDs) and effect of superflab is also investigated for dose reduction

Evidence for a Specific Integrative Mechanism for Episodic Memory Mediated by AMPA/kainate Receptors in a Circuit Involving Medial Prefrontal Cortex and Hippocampal CA3 Region.

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de Souza Silva, Maria A; Huston, Joseph P; Wang, An-Li; Petri, David; Chao, Owen Yuan-Hsin

2016-07-01

We asked whether episodic-like memory requires neural mechanisms independent of those that mediate its component memories for "what," "when," and "where," and if neuronal connectivity between the medial prefrontal cortex (mPFC) and the hippocampus (HPC) CA3 subregion is essential for episodic-like memory. Unilateral lesion of the mPFC was combined with unilateral lesion of the CA3 in the ipsi- or contralateral hemispheres in rats. Episodic-like memory was tested using a task, which assesses the integration of memories for "what, where, and when" concomitantly. Tests for novel object recognition (what), object place (where), and temporal order memory (when) were also applied. Bilateral disconnection of the mPFC-CA3 circuit by N-methyl-d-aspartate (NMDA) lesions disrupted episodic-like memory, but left the component memories for object, place, and temporal order, per se, intact. Furthermore, unilateral NMDA lesion of the CA3 plus injection of (6-cyano-7-nitroquinoxaline-2,3-dione) (CNQX) (AMPA/kainate receptor antagonist), but not AP-5 (NMDA receptor antagonist), into the contralateral mPFC also disrupted episodic-like memory, indicating the mPFC AMPA/kainate receptors as critical for this circuit. These results argue for a selective neural system that specifically subserves episodic memory, as it is not critically involved in the control of its component memories for object, place, and time. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Ultra-fast speech comprehension in blind subjects engages primary visual cortex, fusiform gyrus, and pulvinar – a functional magnetic resonance imaging (fMRI) study

Science.gov (United States)

2013-01-01

Background Individuals suffering from vision loss of a peripheral origin may learn to understand spoken language at a rate of up to about 22 syllables (syl) per second - exceeding by far the maximum performance level of normal-sighted listeners (ca. 8 syl/s). To further elucidate the brain mechanisms underlying this extraordinary skill, functional magnetic resonance imaging (fMRI) was performed in blind subjects of varying ultra-fast speech comprehension capabilities and sighted individuals while listening to sentence utterances of a moderately fast (8 syl/s) or ultra-fast (16 syl/s) syllabic rate. Results Besides left inferior frontal gyrus (IFG), bilateral posterior superior temporal sulcus (pSTS) and left supplementary motor area (SMA), blind people highly proficient in ultra-fast speech perception showed significant hemodynamic activation of right-hemispheric primary visual cortex (V1), contralateral fusiform gyrus (FG), and bilateral pulvinar (Pv). Conclusions Presumably, FG supports the left-hemispheric perisylvian “language network”, i.e., IFG and superior temporal lobe, during the (segmental) sequencing of verbal utterances whereas the collaboration of bilateral pulvinar, right auditory cortex, and ipsilateral V1 implements a signal-driven timing mechanism related to syllabic (suprasegmental) modulation of the speech signal. These data structures, conveyed via left SMA to the perisylvian “language zones”, might facilitate – under time-critical conditions – the consolidation of linguistic information at the level of verbal working memory. PMID:23879896

The prefrontal cortex shows context-specific changes in effective connectivity to motor or visual cortex during the selection of action or colour

DEFF Research Database (Denmark)

Rowe, James B.; Stephan, Klaas E.; Friston, Karl

2005-01-01

The role of the prefrontal cortex remains controversial. Neuroimaging studies support modality-specific and process-specific functions related to working memory and attention. Its role may also be defined by changes in its influence over other brain regions including sensory and motor cortex. We...... used functional magnetic imaging (fMRI) to study the free selection of actions and colours. Control conditions used externally specified actions and colours. The prefrontal cortex was activated during free selection, regardless of modality, in contrast to modality-specific activations outside...... included high-order interactions between modality, selection and regional activity. There was greater coupling between prefrontal cortex and motor cortex during free selection and action tasks, and between prefrontal cortex and visual cortex during free selection of colours. The results suggest...

External root resorption during orthodontic treatment in root-filled teeth and contralateral teeth with vital pulp: A clinical study of contributing factors.

Science.gov (United States)

Lee, Yun Ju; Lee, Tae Yeon

2016-01-01

There is a lack of research to support the belief that root canal treatment can be considered for stopping or decreasing external apical root resorption (EARR). There is conflicting evidence as to whether root-filled teeth are more or less likely to experience EARR after orthodontic treatment. The purpose of this study was to compare the degree of EARR of root-filled teeth with that of contralateral teeth with vital pulp after fixed orthodontic treatment. The study sample consisted of 35 patients aged 25.23 ± 4.92 years who had at least 1 root-filled tooth before orthodontic treatment. Digital panoramic radiographs of each patient taken before and after orthodontic treatment were used to measure the EARR. The Student t test for matched pairs and the Pearson correlation analysis were applied. The mean EARR values were 0.22 (0.14, 0.35) for root-filled teeth and 0.87 (0.59, 1.31) for contralateral teeth with vital pulp, indicating significantly less EARR for root-filled teeth compared with the contralateral teeth with vital pulp after orthodontic treatment. EARR was influenced by the patient's age, treatment duration, treatment type, and periapical pathosis, but not by tooth type and sex. Root-filled teeth appear to be associated with significantly less EARR than are contralateral teeth with vital pulp. This study suggests that the possible complication of EARR in root-filled teeth may not be an important consideration in orthodontic treatment planning, and root canal treatment can be considered for stopping or decreasing EARR when severe EARR occurs during orthodontic treatment. Copyright © 2016 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

Food related processes in the insular cortex

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Sabine eFrank

2013-08-01

Full Text Available The insular cortex is a multimodal brain region with regional cytoarchitectonic differences indicating various functional specializations. As a multisensory neural node, the insular cortex integrates perception, emotion, interoceptive awareness, cognition, and gustation. Regarding the latter, predominantly the anterior part of the insular cortex is regarded as the primary taste cortex.In this review, we will specifically focus on the involvement of the insula in food processing and on multimodal integration of food-related items. Influencing factors of insular activation elicited by various foods range from calorie-content to the internal physiologic state, body mass index or eating behavior. Sensory perception of food-related stimuli including seeing, smelling, and tasting elicits increased activation in the anterior and mid-dorsal part of the insular cortex. Apart from the pure sensory gustatory processing, there is also a strong association with the rewarding/hedonic aspects of food items, which is reflected in higher insular activity and stronger connections to other reward-related areas. Interestingly, the processing of food items has been found to elicit different insular activation in lean compared to obese subjects and in patients suffering from an eating disorder (anorexia nervosa, bulimia nervosa. The knowledge of functional differences in the insular cortex opens up the opportunity for possible noninvasive treatment approaches for obesity and eating disorders. To target brain functions directly, real-time functional magnetic resonance imaging neurofeedback offers a state-of-the-art tool to learn to control the anterior insular cortex activity voluntarily. First evidence indicates that obese adults have an enhanced ability to regulate the anterior insular cortex.

System Identification Algorithm Analysis of Acupuncture Effect on Mean Blood Flux of Contralateral Hegu Acupoint

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Guangjun Wang

2012-01-01

Full Text Available Background. Acupoints (belonging to 12 meridians which have the same names are symmetrically distributed on the body. It has been proved that acupoints have certain biological specificities different from the normal parts of the body. However, there is little evidence that acupoints which have the same name and are located bilaterally and symmetrically have lateralized specificity. Thus, researching the lateralized specificity and the relationship between left-side and right-side acupuncture is of special importance. Methodology and Principal Findings. The mean blood flux (MBF in both Hegu acupoints was measured by Moor full-field laser perfusion imager. With the method of system identification algorithm, the output distribution in different groups was acquired, based on different acupoint stimulation and standard signal input. It is demonstrated that after stimulation of the right Hegu acupoint by needle, the output value of MBF in contralateral Hegu acupoint was strongly amplified, while after acupuncturing the left Hegu acupoint, the output value of MBF in either side Hegu acupoint was amplified moderately. Conclusions and Significance. This paper indicates that the Hegu acupoint has lateralized specificity. After stimulating the ipsilateral Hegu acupoint, symmetry breaking will be produced in contrast to contralateral Hegu acupoint stimulation.

MRI volumetry of prefrontal cortex

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Sheline, Yvette I.; Black, Kevin J.; Lin, Daniel Y.; Pimmel, Joseph; Wang, Po; Haller, John W.; Csernansky, John G.; Gado, Mokhtar; Walkup, Ronald K.; Brunsden, Barry S.; Vannier, Michael W.

1995-05-01

Prefrontal cortex volumetry by brain magnetic resonance (MR) is required to estimate changes postulated to occur in certain psychiatric and neurologic disorders. A semiautomated method with quantitative characterization of its performance is sought to reliably distinguish small prefrontal cortex volume changes within individuals and between groups. Stereological methods were tested by a blinded comparison of measurements applied to 3D MR scans obtained using an MPRAGE protocol. Fixed grid stereologic methods were used to estimate prefrontal cortex volumes on a graphic workstation, after the images are scaled from 16 to 8 bits using a histogram method. In addition images were resliced into coronal sections perpendicular to the bicommissural plane. Prefrontal cortex volumes were defined as all sections of the frontal lobe anterior to the anterior commissure. Ventricular volumes were excluded. Stereological measurement yielded high repeatability and precision, and was time efficient for the raters. The coefficient of error was volumetry by stereology can yield accurate and repeatable measurements. Small frontal lobe volume reductions in patients with brain disorders such as depression and schizophrenia can be efficiently assessed using this method.

Cortical inhibition effect in musicians and non-musicians using P300 with and without contralateral stimulation.

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Rabelo, Camila Maia; Neves-Lobo, Ivone Ferreira; Rocha-Muniz, Caroline Nunes; Ubiali, Thalita; Schochat, Eliane

2015-01-01

Musicians have more robust and efficient neural responses in the cortical and sub-cortical regions, demonstrating that musical experience benefits the processing of both non-linguistic and linguistic stimuli. This study aimed to verify P300's latency and amplitude behavioral using contralateral stimulation in musicians and non-musicians. This was a case-control study. Subjects were divided in two groups: musicians, comprising 30 professional musicians, and non-musicians, comprising 25 subjects without musical experience. The present study showed that the musicians had lower latencies and higher amplitudes than the non-musicians in the P300 without contralateral noise. For the P300 amplitude values, the difference between groups persisted, and the musicians presented significantly higher amplitude values compared with the non-musicians; additionally, the analysis of the noise effect on the P300 response showed that the latency values were significantly increased in the musicians. The central auditory nervous system of musicians presents peculiar characteristics of electrophysiological responses probably due to the plasticity imposed by musical practice. Copyright © 2014 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Clinical Application of Foci Contralateral Facial Artery Myomucosal Flap for Tongue Defect Repair

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Mengxiong Pan, MS

2018-02-01

Full Text Available Summary:. This study aims to investigate the clinical efficacy of foci contralateral facial artery myomucosal flap (FAMF in repairing the defect of tongue after tumor resection. There were 10 cases who received the operation to repair tongue tissue defects caused by tumor resection from January 2010 to January 2016. FAMF flap size ranged from 2.5 × 3 cm to 5 × 5 cm. All flaps survived after surgery, and no local necrosis occurred. For the donor and receptor sites of 10 cases, 8 cases got wounds healed at stage I, wound dehiscence of donor site occurred in 2 cases, and the dehisced wounds were healed after local cleaning. All 10 patients were followed up for 13 months to 5 years, with an average of 2 years and 4 months. No obvious deformity appeared on face after surgery, and there was no mouth floor leakage. After surgery, 3 cases had clinical manifestations of facial nerve marginal mandibular branch injury and returned to normal in 3 months. All patients had a limitation for mouth opening after surgery, 9 cases returned to normal after 1 year, and 1 case still had a mild limitation for mouth opening. There was no impact on patients’ eating, swallowing, language, or other functions. The foci contralateral FAMF surgery is simple and brings ideal plastic effect, high survival rate of flap, less donor site lesion, simple postoperative care, no breaking after surgery, and no impact on radical cure of tumor, which is suitable for repairing defect of tongue.

Retinotopic Patterns of Correlated Fluctuations in Visual Cortex Reflect the Dynamics of Spontaneous Perceptual Suppression

NARCIS (Netherlands)

Donner, T.H.; Sagi, D.; Bonneh, Y.S.; Heeger, D.J.

2013-01-01

While viewing certain stimuli, perception changes spontaneously in the face of constant input. For example, during "motion-induced blindness" (MIB), a small salient target spontaneously disappears and reappears when surrounded by a moving mask. Models of such bistable perceptual phenomena posit

Contralateral lesions detected by preoperative MRI in patients with recently diagnosed breast cancer: Application of MR CAD in differentiation of benign and malignant lesions

International Nuclear Information System (INIS)

Cho, Nariya; Kim, Sun Mi; Park, Jeong Seon; Jang, Mijung; Kim, Soo-Yeon; Chang, Jung Min; Moon, Woo Kyung

2012-01-01

Objectives: To retrospectively investigate the added value of kinetic features measured by computer-aided diagnosis (CAD) for differentiating benign and malignant contralateral breast lesions detected by preoperative MRI in breast cancer patients. Methods: This study was approved by our institutional review board, and the requirement for informed consent was waived. Fifty-two breast MR images and their CAD kinetic features were obtained for 52 consecutive breast cancer patients with contralateral breast lesions detected by preoperative MRI and confirmed by excision (23 cancers and 29 benign lesions). Three experienced radiologists independently reviewed the MR images without CAD information and assessed probabilities of malignancy. Four weeks later, these probabilities were reanalyzed using stored CAD data. Diagnostic performances and detection rates of delayed washout components were compared between interpretations without and with CAD for each reader. Results: Use of MR CAD increased detection of washout component by 2.4- to 3.7-fold than visual assessment for enhancing contralateral lesions, which increased sensitivity (91% vs. 87% in reader 1; 96% vs. 74% in reader 2; 91% vs. 70% in reader 3) and decreased specificity, but statistical significance was only found for decreased specificity in one reader (52% vs. 28%, P = 0.039), and overall performance (areas under ROC curves 0.672 vs. 0.616 in reader 1; 0.624 vs. 0.603 in reader 2; 0.706 vs. 0.590 in reader 3) remained unimproved. Conclusion: Addition of MR CAD increased sensitivity and decreased specificity than radiologist's assessment alone for differentiating benign and malignant contralateral lesions in breast cancer patients and overall performance remained unimproved.

Case-control study of risk factors for the development of laminitis in the contralateral limb in Equidae with unilateral lameness

International Nuclear Information System (INIS)

Peloso, J.G.; Cohen, N.D.; Walker, M.A.; Watkins, J.P.; Gayle, J.M.; Moyer, W.

1996-01-01

To identify risk factors associated with development of laminitis of the supporting limb in Equidae with unilateral laminitis and to determine the radiographic appearance of this type of laminitis. Retrospective analysis of medical records. 20 Equidae with unilateral lameness that developed laminitis of the contralateral limb. Case animals were compared with matched and unmatched populations of control animals that did not develop contralateral limb laminitis. Lateromedial radiographic projections of affected feet were evaluated for evidence of laminitis. Body weight of case animals was not significantly different from that of control animals, but number of days that control animals were lame prior to recovery was significantly less than number of days that case animals were lame prior to the onset of laminitis. Lateromedial radiographic projections of the foot of the support limb were available for 16 of the 20 case animals. For all 16, thickness of the soft tissue dorsal to the distal phalanx was > 29% of the palmar cortical length of the distal phalanx, but only 1 had evidence of rotation of the distal phalanx. The proportion of case animals that were euthanatized was significantly greater than the proportion of control animals that were euthanatized. Duration of lameness, but not body weight, was a risk factor for development of laminitis in the contralateral limb in Equidae with unilateral lameness, and animals that developed this complication were more likely to be euthanatized than were animals that did not

IS PAIN IN ONE KNEE ASSOCIATED WITH ISOMETRIC MUSCLE STRENGTH IN THE CONTRALATERAL LIMB? - DATA FROM THE OSTEOARTHRITIS INITIATIVE (OAI)

Science.gov (United States)

Steidle, E.; Wirth, W.; Glass, N.; Ruhdorfer, A.; Cotofana, S.; Eckstein, F.; Segal, N. A.

2014-01-01

Objective Knee pain and muscle weakness confer risk for knee osteoarthritis incidence and progression. The purpose of this study was to determine whether unilateral knee pain influences contralateral thigh muscle strength. Design Of 4796 Osteoarthritis Initiative participants, 224 (mean±SD age 63.9±8.9 years) cases could be matched to a control. Cases were defined as having unilateral knee pain (numerical rating scale (NRS)≥4/10; ≥infrequent pain) and one pain-free knee (NRS 0–1; ≤infrequent pain; WOMAC≤1). Controls were defined as having bilaterally pain-free knees (NRS 0–1; ≤infrequent pain; WOMAC≤1). Maximal isometric muscle strength [N] was compared between limbs in participants with unilateral pain (cases), and between pain-free limbs of cases and controls. Results Knee extensor/flexor strength in pain-free limbs of cases was lower than in bilaterally pain-free controls (−5.5%/–8.4%; p=0.043/p=0.022). Within cases, maximum extensor/flexor strength was significantly lower in the painful than in the pain-free limb (−6.4%/4.1%; pstrength in limbs without knee pain is associated with the pain status of the contralateral knee. The strength difference between unilateral pain-free cases and matched bilateral pain-free controls was similar to that between limbs in persons with unilateral knee pain. Lower strength due to contralateral knee pain might be centrally mediated. PMID:25768069

Study of external root resorption during orthodontic treatment in root filled teeth compared with their contralateral teeth with vital pulps.

Science.gov (United States)

Llamas-Carreras, J M; Amarilla, A; Solano, E; Velasco-Ortega, E; Rodríguez-Varo, L; Segura-Egea, J J

2010-08-01

To determine whether root filled teeth and those with vital pulps exhibit a similar degree of external root resorption (ERR) as a consequence of orthodontic treatment. The study sample consisted of 77 patients, with a mean age of 32.7 +/- 10.7 years, who had one root filled tooth before completion of multiband/bracket orthodontic therapy for at least 1 year. For each patient, digital panoramic radiographs taken before and after orthodontic treatment were used to determine the proportion of external root resorption (PRR), defined as the ratio between the root resorption in the root filled tooth and that in its contralateral tooth with a vital pulp. The student's t-test, anova and logistic regression analysis were used to determine statistical significance. The mean PRR was 1.00 +/- 0.13, indicating that, in the total sample, there were no significant differences in root resorption in the root filled teeth and their contralateral teeth with vital pulps. Multivariate logistic regression analysis suggested that PRR was significantly greater in incisors (P = 0.0014; odds ratio = 6.2885, C.I. 95% = 2.0-19.4), compared to other teeth, and in women (P = 0.0255; odds ratio = 4.2, C.I. 95% = 1.2-14.6), compared to men. There was no significant difference in the amount or severity of external root resorption during orthodontic movement between root filled teeth and their contralateral teeth with vital pulps.

Changes in Nitric Oxide Releases of the Contralateral Acupoint during and after Laser Acupuncture at Bilateral Same-Name Acupoints in Human

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Wan-Ling Jiang

2017-01-01

Full Text Available Objective. The purpose of the study was to examine the effects of laser acupuncture (LA at right Neiguan (RPC6/left Neiguan (LPC6 acupoints on the releases of nitric oxide (NO in the treated and contralateral/nontreated PC6, compared to the nonacupoint control area. Methods. 24 mW LA at RPC6, LPC6, and nonacupoint in 22 healthy subjects for 40 min: sterilized dialysis tube was taped to the nontreated PC6/nonacupoint during the treatment and immediately taped to the treated and nontreated PC6/nonacupoint after LA removal. NO-scavenging compound was injected into the tube for 40 min to absorb the molecular which was tested by spectrophotometry in a blinded fashion. Results. LA-induced NO releases over PC6 acupoints for the nontreated and treated sides all significantly increased after LA removal, but for the nontreated acupoints they did not change during LA stimulation. LA at RPC6 induced the more release of the NO at contralateral side than stimulating LPC6, but not on nonacupoints. The results suggest that LA-induced NO release over contralateral acupoint and NO release resulting from the lateralized specificity all are different and specific to the acupoint within different time course. Conclusions. LA-evoked NO release over acupoints could improve the neurogenic, endothelial activity of the vessel wall to further facilitate microcirculation.

GE-42INTEGRATED RADIOGRAPHIC AND PHYLOGENETIC CASE STUDY OF A PRIMARY AND CONTRALATERAL RECURRENT GLIOMA

OpenAIRE

Nagarajan, Raman; Barajas, Ramon; Mazor, Tali; Phillips, Joanna; Ma, Jianhui; Hong, Chibo; Johnson, Brett; Dayal, Manisha; Cha, Soonmee; Nakamura, Jean; Berger, Mitchel; Chang, Susan; Furnari, Frank; Taylor, Barry; Costello, Joseph

2014-01-01

Extensive neuropil invasion is a hallmark of glioma growth and a subset of tumors demonstrate recurrence in the contralateral hemisphere without a path of tumor spread detected by MR imaging. We used an integrated genomic and radiographic approach to study a patient with a right nonenhancing insular mass histologically diagnosed as IDH1/2 wild-type anaplastic astrocytoma (AA) and a punctate nonenhancing T2 hyperintense focus within the left middle frontal gyrus subcortical white matter. Follo...

Mammographic findings after reshaping with autoprosthesis in women undergoing contralateral breast reconstruction and mastectomy.

Science.gov (United States)

Scaperrotta, Gianfranco; Capalbo, Emanuela; Ferranti, Claudio; Falco, Giuseppe; Nava, Maurizio B; Di Leo, Gianni; Marchesini, Monica; Suman, Laura; Panizza, Pietro

2016-01-01

Breast reduction and mastopexy combined with inferior dermo-lipo-glandular flap (autoprosthesis) gives good breast shape, long-term projection, and upper pole fullness. We assess the impact on breast oncologic surveillance compared to other techniques. A total of 105 patients who underwent mastectomy and reconstruction were divided into 3 groups of 35 patients each: groups 1 and 2 include patients with contralateral breast symmetrization performed with and without autoprosthesis technique, respectively. Group 3 is a control group without contralateral breast reshaping. On mammography, edema, skin thickening, architectural distortion, and calcifications were recorded, as well as further diagnostic examinations, biopsies, and surgical treatments required. Statistically significant differences (p<0.001) in the first follow-up mammography between groups 1 and 2 were stromal edema (6% vs 51%) and architectural distortion (74% vs 63%). The latest findings meant architectural distortion also have significant difference (p<0.001) in the last mammography (79% vs 66%). Microcalcification has statistically significant difference (p<0.001) in the latest postsurgical mammography, increased in group 1. Skin thickening had a similar course in either group. Mammography follow-up was not impaired in most cases notwithstanding the parenchyma distortion as compared with mammography after breast-conserving surgery. Four core biopsies were performed in both groups: 3 new breast cancers and 1 benign epithelial hyperplasia were found. No difficulties were found impairing mammographic evaluation in patients treated with autoprosthesis as compared to other techniques.

Stent assisted coil embolization of a dissecting aneurysm of the vertebral artery: a case involving a patient with hypoplasia of the contralateral vertebral artery

International Nuclear Information System (INIS)

Kim, Hyun Jin; Jeong, Hae Woong; Cho, Jae Kwoeng; Park, Jeong Hoon; Koo, Yong Woon; Baik, Seung Kug

2002-01-01

A dissecting aneurysm of the vertebral artery may be treated conservatively, surgically, or using an endovascular approach. Proximal clipping, wrapping or trapping are surgical treatment methods, and endovascular treatment with coils and balloons is performed where a dissecting aneurysm is located near the midline or the appropriate surgical manipulation is difficult. As the contralateral vertebral artery of this patient was hypoplastic, the stent-assisted coil embolization technique was employed to preserve the ipsilateral vertebral artery. We describe a clinical case of dissecting aneurysm of the vertebral artery occurring in a patient in whom a hypoplastic contralateral vertebral artery was successfully treated

Medial cortex activity, self-reflection and depression.

Science.gov (United States)

Johnson, Marcia K; Nolen-Hoeksema, Susan; Mitchell, Karen J; Levin, Yael

2009-12-01

Using functional magnetic resonance imaging, we investigated neural activity associated with self-reflection in depressed [current major depressive episode (MDE)] and healthy control participants, focusing on medial cortex areas previously shown to be associated with self-reflection. Both the MDE and healthy control groups showed greater activity in anterior medial cortex (medial frontal gyrus, anterior cingulate gyrus) when cued to think about hopes and aspirations compared with duties and obligations, and greater activity in posterior medial cortex (precuneus, posterior cingulate) when cued to think about duties and obligations (Experiment 1). However, the MDE group showed less activity than controls in the same area of medial frontal cortex when self-referential cues were more ambiguous with respect to valence (Experiment 2), and less deactivation in a non-self-referential condition in both experiments. Furthermore, individual differences in rumination were positively correlated with activity in both anterior and posterior medial cortex during non-self-referential conditions. These results provide converging evidence for a dissociation of anterior and posterior medial cortex depending on the focus of self-relevant thought. They also provide neural evidence consistent with behavioral findings that depression is associated with disruption of positively valenced thoughts in response to ambiguous cues, and difficulty disengaging from self-reflection when it is appropriate to do so.

MEG reveals a fast pathway from somatosensory cortex to occipital areas via posterior parietal cortex in a blind subject.

Science.gov (United States)

Ioannides, Andreas A; Liu, Lichan; Poghosyan, Vahe; Saridis, George A; Gjedde, Albert; Ptito, Maurice; Kupers, Ron

2013-01-01

Cross-modal activity in visual cortex of blind subjects has been reported during performance of variety of non-visual tasks. A key unanswered question is through which pathways non-visual inputs are funneled to the visual cortex. Here we used tomographic analysis of single trial magnetoencephalography (MEG) data recorded from one congenitally blind and two sighted subjects after stimulation of the left and right median nerves at three intensities: below sensory threshold, above sensory threshold and above motor threshold; the last sufficient to produce thumb twitching. We identified reproducible brain responses in the primary somatosensory (S1) and motor (M1) cortices at around 20 ms post-stimulus, which were very similar in sighted and blind subjects. Time-frequency analysis revealed strong 45-70 Hz activity at latencies of 20-50 ms in S1 and M1, and posterior parietal cortex Brodmann areas (BA) 7 and 40, which compared to lower frequencies, were substantially more pronounced in the blind than the sighted subjects. Critically, at frequencies from α-band up to 100 Hz we found clear, strong, and widespread responses in the visual cortex of the blind subject, which increased with the intensity of the somatosensory stimuli. Time-delayed mutual information (MI) revealed that in blind subject the stimulus information is funneled from the early somatosensory to visual cortex through posterior parietal BA 7 and 40, projecting first to visual areas V5 and V3, and eventually V1. The flow of information through this pathway occurred in stages characterized by convergence of activations into specific cortical regions. In sighted subjects, no linked activity was found that led from the somatosensory to the visual cortex through any of the studied brain regions. These results provide the first evidence from MEG that in blind subjects, tactile information is routed from primary somatosensory to occipital cortex via the posterior parietal cortex.

Analysis of Time-Dependent Brain Network on Active and MI Tasks for Chronic Stroke Patients.

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Da-Hye Kim

Full Text Available Several researchers have analyzed brain activities by investigating brain networks. However, there is a lack of the research on the temporal characteristics of the brain network during a stroke by EEG and the comparative studies between motor execution and imagery, which became known to have similar motor functions and pathways. In this study, we proposed the possibility of temporal characteristics on the brain networks of a stroke. We analyzed the temporal properties of the brain networks for nine chronic stroke patients by the active and motor imagery tasks by EEG. High beta band has a specific role in the brain network during motor tasks. In the high beta band, for the active task, there were significant characteristics of centrality and small-worldness on bilateral primary motor cortices at the initial motor execution. The degree centrality significantly increased on the contralateral primary motor cortex, and local efficiency increased on the ipsilateral primary motor cortex. These results indicate that the ipsilateral primary motor cortex constructed a powerful subnetwork by influencing the linked channels as compensatory effect, although the contralateral primary motor cortex organized an inefficient network by using the connected channels due to lesions. For the MI task, degree centrality and local efficiency significantly decreased on the somatosensory area at the initial motor imagery. Then, there were significant correlations between the properties of brain networks and motor function on the contralateral primary motor cortex and somatosensory area for each motor execution/imagery task. Our results represented that the active and MI tasks have different mechanisms of motor acts. Based on these results, we indicated the possibility of customized rehabilitation according to different motor tasks. We expect these results to help in the construction of the customized rehabilitation system depending on motor tasks by understanding temporal

Decreased resting functional connectivity after traumatic brain injury in the rat.

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Asht Mangal Mishra

Full Text Available Traumatic brain injury (TBI contributes to about 10% of acquired epilepsy. Even though the mechanisms of post-traumatic epileptogenesis are poorly known, a disruption of neuronal networks predisposing to altered neuronal synchrony remains a viable candidate mechanism. We tested a hypothesis that resting state BOLD-fMRI functional connectivity can reveal network abnormalities in brain regions that are connected to the lesioned cortex, and that these changes associate with functional impairment, particularly epileptogenesis. TBI was induced using lateral fluid-percussion injury in seven adult male Sprague-Dawley rats followed by functional imaging at 9.4T 4 months later. As controls we used six sham-operated animals that underwent all surgical operations but were not injured. Electroencephalogram (EEG-functional magnetic resonance imaging (fMRI was performed to measure resting functional connectivity. A week after functional imaging, rats were implanted with bipolar skull electrodes. After recovery, rats underwent pentyleneterazol (PTZ seizure-susceptibility test under EEG. For image analysis, four pairs of regions of interests were analyzed in each hemisphere: ipsilateral and contralateral frontal and parietal cortex, hippocampus, and thalamus. High-pass and low-pass filters were applied to functional imaging data. Group statistics comparing injured and sham-operated rats and correlations over time between each region were calculated. In the end, rats were perfused for histology. None of the rats had epileptiform discharges during functional imaging. PTZ-test, however revealed increased seizure susceptibility in injured rats as compared to controls. Group statistics revealed decreased connectivity between the ipsilateral and contralateral parietal cortex and between the parietal cortex and hippocampus on the side of injury as compared to sham-operated animals. Injured animals also had abnormal negative connectivity between the ipsilateral and

Ipsilateral hemiparesis and contralateral lower limb paresis caused by anterior cerebral artery territory infarct.

Science.gov (United States)

Xu, Yongfeng; Liu, Lan

2016-07-01

Ipsilateral hemiparesis is rare after a supratentorial stroke, and the role of reorganization in the motor areas of unaffected hemisphere is important for the rehabilitation of the stroke patients. In this study, we present a patient who had a subclinical remote infarct in the right pons developed ipsilateral hemiparesis and contralateral lower limb paresis caused by a new infarct in the left anterior cerebral artery territory. Our case suggests that the motor areas of the unaffected hemisphere might be reorganized after stroke, which is important for the rehabilitation of stroke patients.

Induced renal artery stenosis in rabbits: magnetic resonance imaging, angiography, and radionuclide determination of blood volume and blood flow

International Nuclear Information System (INIS)

Mitchell, D.G.; Tobin, M.; LeVeen, R.; Tomaczewski, J.; Alavi, A.; Staum, M.; Kundel, H.

1988-01-01

To investigate the ability of MRI to detect alterations due to renal ischemia, a rabbit renal artery stenosis (RAS) model was developed. Seven rabbits had RAS induced by surgically encircling the artery with a polyethylene band which had a lumen of 1 mm, 1 to 2 weeks prior to imaging. The stenosis was confirmed by angiography, and the rabbits were then imaged in a 1.4 T research MRI unit. T1 was calculated using four inversion recovery sequences with different inversion times. Renal blood flow, using 113 Sn-microspheres, and regional water content by drying were then measured. The average T1 of the inner medulla was shorter for the ischemia (1574 msec) than for the contralateral kidney (1849 msec), while no change ws noted in the cortex. Ischemic kidneys had less distinct outer medullary zones on IR images with TI = 600 msec than did contralateral or control kidneys. Blood flow to both the cortex and medulla were markedly reduced in ischemic kidneys compared with contralateral kidneys (119.5 vs. 391 ml/min/100 gm for cortex and 19.8 vs. 50.8 ml/min/100 gm for medulla). Renal water and blood content were less affected. Our rabbit model of renal artery stenosis with MRI, radionuclide, and angiographic correlation has the potential to increase our understanding of MR imaging of the rabbit kidney

Glucose consumption and rate constants for sup 18 F-fluorodeoxyglucose in human gliomas

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Ishikawa, Masatsune; Kikuchi, Haruhiko; Nagata, Izumi; Yamagata, Sen; Taki, Waro; Yonekura, Yoshiharu; Nishizawa, Sadahiko; Iwasaki, Yasushi; Mukai, Takao [Kyoto Univ. (Japan). Faculty of Medicine

1990-06-01

To investigate the value of direct measurement of the rate constants by performing {sup 18}F-labeled fluorodeoxyglucose (FDG) studies of glucose consumption in human gliomas in vivo, a kinetic method with 3- and 4-parameter rate constant models for FDG uptake was used to analyze data from dynamic scans obtained by positron emission tomography after injection of FDG into 14 patients with glioma. The results were compared with those obtained by the autoradiographic method using 3- and 4-parameter rate constant models. There were no significant differences in the glucose consumption calculated by the four different methods both in the gliomas and in the contralateral intact cortex. It was found that the rate constant k4 could be neglected in calculation of glucose consumption in gliomas as well as in the contralateral intact cortex. The rate constant k3, an index of hexokinase function, was higher in malignant gliomas than in benign gliomas and was close to that in the contralateral cortex. This study indicates that the 3-parameter autoradiographic method, which is the most common one used in clinical practice, is reliable for the calculation of glucose consumption in human gliomas. Furthermore, direct measurement of the regional rate constants for FDG by the kinetic method was found to be useful for evaluation of the biochemical and physiological characteristics of human gliomas in vivo. (author).

Glucose consumption and rate constants for 18F-fluorodeoxyglucose in human gliomas

International Nuclear Information System (INIS)

Ishikawa, Masatsune; Kikuchi, Haruhiko; Nagata, Izumi; Yamagata, Sen; Taki, Waro; Yonekura, Yoshiharu; Nishizawa, Sadahiko; Iwasaki, Yasushi; Mukai, Takao

1990-01-01

To investigate the value of direct measurement of the rate constants by performing 18 F-labeled fluorodeoxyglucose (FDG) studies of glucose consumption in human gliomas in vivo, a kinetic method with 3- and 4-parameter rate constant models for FDG uptake was used to analyze data from dynamic scans obtained by positron emission tomography after injection of FDG into 14 patients with glioma. The results were compared with those obtained by the autoradiographic method using 3- and 4-parameter rate constant models. There were no significant differences in the glucose consumption calculated by the four different methods both in the gliomas and in the contralateral intact cortex. It was found that the rate constant k4 could be neglected in calculation of glucose consumption in gliomas as well as in the contralateral intact cortex. The rate constant k3, an index of hexokinase function, was higher in malignant gliomas than in benign gliomas and was close to that in the contralateral cortex. This study indicates that the 3-parameter autoradiographic method, which is the most common one used in clinical practice, is reliable for the calculation of glucose consumption in human gliomas. Furthermore, direct measurement of the regional rate constants for FDG by the kinetic method was found to be useful for evaluation of the biochemical and physiological characteristics of human gliomas in vivo. (author)

Auditory intensity processing: Effect of MRI background noise.

Science.gov (United States)

Angenstein, Nicole; Stadler, Jörg; Brechmann, André

2016-03-01

Studies on active auditory intensity discrimination in humans showed equivocal results regarding the lateralization of processing. Whereas experiments with a moderate background found evidence for right lateralized processing of intensity, functional magnetic resonance imaging (fMRI) studies with background scanner noise suggest more left lateralized processing. With the present fMRI study, we compared the task dependent lateralization of intensity processing between a conventional continuous echo planar imaging (EPI) sequence with a loud background scanner noise and a fast low-angle shot (FLASH) sequence with a soft background scanner noise. To determine the lateralization of the processing, we employed the contralateral noise procedure. Linearly frequency modulated (FM) tones were presented monaurally with and without contralateral noise. During both the EPI and the FLASH measurement, the left auditory cortex was more strongly involved than the right auditory cortex while participants categorized the intensity of FM tones. This was shown by a strong effect of the additional contralateral noise on the activity in the left auditory cortex. This means a massive reduction in background scanner noise still leads to a significant left lateralized effect. This suggests that the reversed lateralization in fMRI studies with loud background noise in contrast to studies with softer background cannot be fully explained by the MRI background noise. Copyright © 2016 Elsevier B.V. All rights reserved.

Functional relationship between the cerebrum and cerebellum in normal subjects

International Nuclear Information System (INIS)

Hanyu, Haruo; Arai, Hisayuki; Hatano, Nobuyoshi; Abe, Shinei; Katsunuma, Hideyo

1991-01-01

To determine whether a functional relationship between the cerebrum and cerebellum exists in normal subjects, the correlation between asymmetry in cerebral blood flow and asymmetry in cerebellar blood flow was investigated. Twenty-one healthy right-handed subjects were studied using SPECT with N-isopropyl-p-( 123 I)iodoamphetamine while in a resting state. The asymmetry index (AI) for both the cerebral and cerebellar hemisphere was calculated as follows. AI=right side - left side/right side + left side/200 (%). A negative correlation was found between AI in the cerebellum and AI in the cerebrum. Especially, AI in the cerebellar hemisphere was significantly correlated with AIs in the upper frontal cortex (r=-0.58, p<0.01), middle frontal cortex (r=-0.55, p<0.02), lower frontal cortex (r=-0.49, p<0.05), and mean cerebral hemisphere (r=-0.52, p<0.02). These results suggest the existence of a functional relationship between the cerebral hemisphere and the contralateral cerebellar hemisphere in the resting state of normal subjects. We strongly suspect that the frontal cortex exert an influence on the function in the contralateral cerebellum, probably due to a transneuronal mechanism, mainly through the corticopontocerebellar pathway. (author)

Metoclopramide unmasks potentially misleading contralateral suppression in patients undergoing adrenal vein sampling for primary aldosteronism.

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Rossitto, Giacomo; Miotto, Diego; Battistel, Michele; Barbiero, Giulio; Maiolino, Giuseppe; Bisogni, Valeria; Sanga, Viola; Rossi, Gian Paolo

2016-11-01

As metoclopramide stimulates aldosterone secretion, we tested its usefulness in the assessment of lateralization of primary aldosteronism by adrenal vein sampling (AVS). Prospective within-patient study in consecutive patients undergoing AVS for primary aldosteronism subtyping. We compared the diagnostic accuracy of baseline and postmetoclopramide lateralization index and relative (to cortisol) aldosterone secretion indices (RASI) for each adrenal gland with aldosterone-producing adenoma (APA) determined by the four corners criteria as the reference diagnosis. We recruited 93 consecutive patients (mean age: 52 years; women 31%). Metoclopramide increased plasma aldosterone in the inferior vena cava and in both adrenal veins. The postmetoclopramide lateralization index was accurate in identifying APA, but did not increase diagnostic accuracy over baseline lateralization index, because the RASI increased similarly in both sides. Conversely, metoclopramide raised RASI to values more than 0.90 bilaterally in non-APA patients allowing accurate identification of factitious aldosterone suppression. In contrast, RASI was 0.90 or less in 48% contralateral to the tumor in APA patients. Regression analysis showed the APA patients with persistent suppression of RASI contralaterally showed a more florid primary aldosteronism phenotype. Metoclopramide does not enhance lateralization of aldosterone excess in APA, but consistently increased the value of RASI in non-APA cases, thus unmasking potentially misleading suppression of aldosterone. Postmetoclopramide RASI may therefore allow a more precise diagnosis when AVS can be achieved only unilaterally.

Is hemiplegic cerebral palsy equivalent to amblyopia of the corticospinal system?

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Eyre, Janet A; Smith, Martin; Dabydeen, Lyvia; Clowry, Gavin J; Petacchi, Eliza; Battini, Roberta; Guzzetta, Andrea; Cioni, Giovanni

2007-11-01

Subjects with severe hemiplegic cerebral palsy have increased ipsilateral corticospinal projections from their noninfarcted cortex. We investigated whether their severe impairment might, in part, be caused by activity-dependent, competitive displacement of surviving contralateral corticospinal projections from the affected cortex by more active ipsilateral corticospinal projections from the nonaffected cortex, thereby compounding the impairment. Transcranial magnetic stimulation (TMS) characterized corticospinal tract development from each hemisphere over the first 2 years in 32 healthy children, 14 children with unilateral stroke, and 25 with bilateral lesions. Magnetic resonance imaging and anatomic studies compared corticospinal tract growth in 13 patients with perinatal stroke with 46 healthy subjects. Infants with unilateral lesions initially had responses after TMS of the affected cortex, which became progressively more abnormal, and seven were eventually lost. There was associated hypertrophy of the ipsilateral corticospinal axons projecting from the noninfarcted cortex. Magnetic resonance imaging and anatomic studies demonstrated hypertrophy of the corticospinal tract from the noninfarcted hemisphere. TMS findings soon after the stroke did not predict impairment; subsequent loss of responses and hypertrophy of ipsilateral corticospinal axons from the noninfarcted cortex predicted severe impairment at 2 years. Infants with bilateral lesions maintained responses to TMS from both hemispheres with a normal pattern of development. Rather than representing "reparative plasticity," increased ipsilateral projections from the noninfarcted cortex compound disability by competitively displacing surviving contralateral corticospinal projections from the infarcted cortex. This may provide a pathophysiological explanation for why signs of hemiplegic cerebral palsy appear late and progress over the first 2 years of life.

Orbitofrontal cortex contribution to working memory. N-back ERP study

International Nuclear Information System (INIS)

Nakao, Yoshiaki; Tamura, Toshiyo; Kodabashi, Atsushi; Fujimoto, Toshiro; Yarita, Masaru

2011-01-01

Remarkable progress in cognitive neuroscience has revealed the involvement of the prefrontal cortex and the orbitofrontal cortex in human working memory, but the orbitofrontal cortex is still one of the least understood regions in the human brain. To elucidate the contribution of the orbitofrontal cortex to human working memory, we studied electroencephalography (EEG) P300 activity in n-back task. We elicited early P3 around 300 ms and late P3 around 360 ms of P300 components in n-back event related potentials (ERP). The amplitudes of the respective peaks changed depending on the working memory load (0-back, 1-back, 2-back, 3-back). We used source analysis to evaluate the orbitofrontal cortex in P3 components. A source model was constructed with the sources seeded from fMRI meta-analysis of n-back task and additional sources in the orbitofrontal cortex and the visual cortex estimated with P100 and late P3 components in the n-back ERP. This source model had more than 99% of GOF (goodness of fit) in n-back ERP. It gave us an insight of brain activity at the positions where sources existed. Early P3 was mainly produced by the dorsolateral prefrontal cortex, the ventrolateral prefrontal cortex, the inferior parietal lobule, the medial posterior parietal and the visual cortex. Late P3 was mainly produced by the medial premotor, the lateral premotor, the frontal pole and the orbitofrontal cortex. The contribution of the frontal pole and the orbitofrontal cortex had peaks around 390 ms which were later than late P3 component. In this study, the method to evaluate the orbitofrontal cortex activity in n-back ERP was provided. Our results elicited the involvement of the orbitofrontal cortex in late P3 component of n-back ERP. (author)

Auditory cortex involvement in emotional learning and memory.

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Grosso, A; Cambiaghi, M; Concina, G; Sacco, T; Sacchetti, B

2015-07-23

Emotional memories represent the core of human and animal life and drive future choices and behaviors. Early research involving brain lesion studies in animals lead to the idea that the auditory cortex participates in emotional learning by processing the sensory features of auditory stimuli paired with emotional consequences and by transmitting this information to the amygdala. Nevertheless, electrophysiological and imaging studies revealed that, following emotional experiences, the auditory cortex undergoes learning-induced changes that are highly specific, associative and long lasting. These studies suggested that the role played by the auditory cortex goes beyond stimulus elaboration and transmission. Here, we discuss three major perspectives created by these data. In particular, we analyze the possible roles of the auditory cortex in emotional learning, we examine the recruitment of the auditory cortex during early and late memory trace encoding, and finally we consider the functional interplay between the auditory cortex and subcortical nuclei, such as the amygdala, that process affective information. We conclude that, starting from the early phase of memory encoding, the auditory cortex has a more prominent role in emotional learning, through its connections with subcortical nuclei, than is typically acknowledged. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

Retropharyngeal Contralateral C7 Nerve Transfer to the Lower Trunk for Brachial Plexus Birth Injury: Technique and Results.

Science.gov (United States)

Vu, Anthony T; Sparkman, Darlene M; van Belle, Christopher J; Yakuboff, Kevin P; Schwentker, Ann R

2018-05-01

Brachial plexus birth injuries with multiple nerve root avulsions present a particularly difficult reconstructive challenge because of the limited availability of donor nerves. The contralateral C7 has been described for brachial plexus reconstruction in adults but has not been well-studied in the pediatric population. We present our technique and results for retropharyngeal contralateral C7 nerve transfer to the lower trunk for brachial plexus birth injury. We performed a retrospective review. Any child aged less than 2 years was included. Charts were analyzed for patient demographic data, operative variables, functional outcomes, complications, and length of follow-up. We had a total of 5 patients. Average nerve graft length was 3 cm. All patients had return of hand sensation to the ulnar nerve distribution as evidenced by a pinch test, unprompted use of the recipient limb without mirror movement, and an Active Movement Scale (AMS) of at least 2/7 for finger and thumb flexion; one patient had an AMS of 7/7 for finger and thumb flexion. Only one patient had return of ulnar intrinsic hand function with an AMS of 3/7. Two patients had temporary triceps weakness in the donor limb and one had clinically insignificant temporary phrenic nerve paresis. No complications were related to the retropharyngeal nerve dissection in any patient. Average follow-up was 3.3 years. The retropharyngeal contralateral C7 nerve transfer is a safe way to supply extra axons to the severely injured arm in brachial plexus birth injuries with no permanent donor limb deficits. Early functional recovery in these patients, with regard to hand function and sensation, is promising. Therapeutic V. Copyright © 2018 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

Substance P signalling in primary motor cortex facilitates motor learning in rats.

Directory of Open Access Journals (Sweden)

Benjamin Hertler

Full Text Available Among the genes that are up-regulated in response to a reaching training in rats, Tachykinin 1 (Tac1-a gene that encodes the neuropeptide Substance P (Sub P-shows an especially strong expression. Using Real-Time RT-PCR, a detailed time-course of Tac1 expression could be defined: a significant peak occurs 7 hours after training ended at the first and second training session, whereas no up-regulation could be detected at a later time-point (sixth training session. To assess the physiological role of Sub P during movement acquisition, microinjections into the primary motor cortex (M1 contralateral to the trained paw were performed. When Sub P was injected before the first three sessions of a reaching training, effectiveness of motor learning became significantly increased. Injections at a time-point when rats already knew the task (i.e. training session ten and eleven had no effect on reaching performance. Sub P injections did not influence the improvement of performance within a single training session, but retention of performance between sessions became strengthened at a very early stage (i.e. between baseline-training and first training session. Thus, Sub P facilitates motor learning in the very early phase of skill acquisition by supporting memory consolidation. In line with these findings, learning related expression of the precursor Tac1 occurs at early but not at later time-points during reaching training.

Substance P signalling in primary motor cortex facilitates motor learning in rats.

Science.gov (United States)

Hertler, Benjamin; Hosp, Jonas Aurel; Blanco, Manuel Buitrago; Luft, Andreas Rüdiger

2017-01-01

Among the genes that are up-regulated in response to a reaching training in rats, Tachykinin 1 (Tac1)-a gene that encodes the neuropeptide Substance P (Sub P)-shows an especially strong expression. Using Real-Time RT-PCR, a detailed time-course of Tac1 expression could be defined: a significant peak occurs 7 hours after training ended at the first and second training session, whereas no up-regulation could be detected at a later time-point (sixth training session). To assess the physiological role of Sub P during movement acquisition, microinjections into the primary motor cortex (M1) contralateral to the trained paw were performed. When Sub P was injected before the first three sessions of a reaching training, effectiveness of motor learning became significantly increased. Injections at a time-point when rats already knew the task (i.e. training session ten and eleven) had no effect on reaching performance. Sub P injections did not influence the improvement of performance within a single training session, but retention of performance between sessions became strengthened at a very early stage (i.e. between baseline-training and first training session). Thus, Sub P facilitates motor learning in the very early phase of skill acquisition by supporting memory consolidation. In line with these findings, learning related expression of the precursor Tac1 occurs at early but not at later time-points during reaching training.

The orbitofrontal cortex and beyond: from affect to decision-making.

Science.gov (United States)

Rolls, Edmund T; Grabenhorst, Fabian

2008-11-01

The orbitofrontal cortex represents the reward or affective value of primary reinforcers including taste, touch, texture, and face expression. It learns to associate other stimuli with these to produce representations of the expected reward value for visual, auditory, and abstract stimuli including monetary reward value. The orbitofrontal cortex thus plays a key role in emotion, by representing the goals for action. The learning process is stimulus-reinforcer association learning. Negative reward prediction error neurons are related to this affective learning. Activations in the orbitofrontal cortex correlate with the subjective emotional experience of affective stimuli, and damage to the orbitofrontal cortex impairs emotion-related learning, emotional behaviour, and subjective affective state. With an origin from beyond the orbitofrontal cortex, top-down attention to affect modulates orbitofrontal cortex representations, and attention to intensity modulates representations in earlier cortical areas of the physical properties of stimuli. Top-down word-level cognitive inputs can bias affective representations in the orbitofrontal cortex, providing a mechanism for cognition to influence emotion. Whereas the orbitofrontal cortex provides a representation of reward or affective value on a continuous scale, areas beyond the orbitofrontal cortex such as the medial prefrontal cortex area 10 are involved in binary decision-making when a choice must be made. For this decision-making, the orbitofrontal cortex provides a representation of each specific reward in a common currency.

Alcohol intake and cigarette smoking and risk of a contralateral breast cancer: The Women's Environmental Cancer and Radiation Epidemiology Study

DEFF Research Database (Denmark)

Knight, J.A.; Bernstein, L.; Largent, J.

2009-01-01

Women with primary breast cancer are at increased risk of developing second primary breast cancer. Few studies have evaluated risk factors for the development of asynchronous contralateral breast cancer in women with breast cancer. In the Women's Environmental Cancer and Radiation Epidemiology St...

Does Contralateral Delay Activity Reflect Working Memory Storage or the Current Focus of Spatial Attention within Visual Working Memory?

Science.gov (United States)

Berggren, Nick; Eimer, Martin

2016-12-01

During the retention of visual information in working memory, event-related brain potentials show a sustained negativity over posterior visual regions contralateral to the side where memorized stimuli were presented. This contralateral delay activity (CDA) is generally believed to be a neural marker of working memory storage. In two experiments, we contrasted this storage account of the CDA with the alternative hypothesis that the CDA reflects the current focus of spatial attention on a subset of memorized items set up during the most recent encoding episode. We employed a sequential loading procedure where participants memorized four task-relevant items that were presented in two successive memory displays (M1 and M2). In both experiments, CDA components were initially elicited contralateral to task-relevant items in M1. Critically, the CDA switched polarity when M2 displays appeared on the opposite side. In line with the attentional activation account, these reversed CDA components exclusively reflected the number of items that were encoded from M2 displays, irrespective of how many M1 items were already held in working memory. On trials where M1 and M2 displays were presented on the same side and on trials where M2 displays appeared nonlaterally, CDA components elicited in the interval after M2 remained sensitive to a residual trace of M1 items, indicating that some activation of previously stored items was maintained across encoding episodes. These results challenge the hypothesis that CDA amplitudes directly reflect the total number of stored objects and suggest that the CDA is primarily sensitive to the activation of a subset of working memory representations within the current focus of spatial attention.

Reproductive Status at First Diagnosis Influences Risk of Radiation-Induced Second Primary Contralateral Breast Cancer in the WECARE Study

Energy Technology Data Exchange (ETDEWEB)

Brooks, Jennifer D., E-mail: brooksj@mskcc.org [Department of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Boice, John D. [International Epidemiology Institute, Rockville, MD and Department of Medicine, Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Vanderbilt School of Medicine, Nashville, TN (United States); Stovall, Marilyn [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Reiner, Anne S. [Department of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Bernstein, Leslie [Division of Cancer Etiology, Department of Population Sciences, Beckman Research Institute and City of Hope Comprehensive Cancer Center, Duarte, CA (United States); John, Esther M. [Cancer Prevention Institute of California, Fremont, CA, and Stanford University School of Medicine and Stanford Cancer Institute, Stanford, CA (United States); Lynch, Charles F. [Department of Epidemiology, University of Iowa, Iowa City, IA (United States); Mellemkjaer, Lene [Institute of Cancer Epidemiology, Danish Cancer Society, Copenhagen (Denmark); Knight, Julia A. [Dalla Lana School of Public Health, University of Toronto and Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario (Canada); Thomas, Duncan C.; Haile, Robert W. [Department of Preventive Medicine, University of Southern California, Los Angeles, CA (United States); Smith, Susan A. [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Capanu, Marinela; Bernstein, Jonine L. [Department of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Shore, Roy E. [Department of Environmental Medicine, New York University, New York, NY (United States); Radiation Effects Research Foundation, Hiroshima (Japan)

2012-11-15

Purpose: Our study examined whether reproductive and hormonal factors before, at the time of, or after radiation treatment for a first primary breast cancer modify the risk of radiation-induced second primary breast cancer. Methods and Materials: The Women's Environmental, Cancer and Radiation Epidemiology (WECARE) Study is a multicenter, population-based study of 708 women (cases) with asynchronous contralateral breast cancer (CBC) and 1399 women (controls) with unilateral breast cancer. Radiotherapy (RT) records, coupled with anthropomorphic phantom simulations, were used to estimate quadrant-specific radiation dose to the contralateral breast for each patient. Rate ratios (RR) and 95% confidence intervals (CI) were computed to assess the relationship between reproductive factors and risk of CBC. Results: Women who were nulliparous at diagnosis and exposed to {>=}1 Gy to the contralateral breast had a greater risk for CBC than did matched unexposed nulliparous women (RR = 2.2; 95% CI, 1.2-4.0). No increased risk was seen in RT-exposed parous women (RR = 1.1; 95% CI, 0.8-1.4). Women treated with RT who later became pregnant (8 cases and 9 controls) had a greater risk for CBC (RR = 6.0; 95% CI, 1.3-28.4) than unexposed women (4 cases and 7 controls) who also became pregnant. The association of radiation with risk of CBC did not vary by number of pregnancies, history of breastfeeding, or menopausal status at the time of first breast cancer diagnosis. Conclusion: Nulliparous women treated with RT were at an increased risk for CBC. Although based on small numbers, women who become pregnant after first diagnosis also seem to be at an increased risk for radiation-induced CBC.

Risk of second primary cancers after testicular cancer in East and West Germany: A focus on contralateral testicular cancers

Science.gov (United States)

Rusner, Carsten; Streller, Brigitte; Stegmaier, Christa; Trocchi, Pietro; Kuss, Oliver; McGlynn, Katherine A; Trabert, Britton; Stang, Andreas

2014-01-01

Testicular cancer survival rates improved dramatically after cisplatin-based therapy was introduced in the 1970s. However, chemotherapy and radiation therapy are potentially carcinogenic. The purpose of this study was to estimate the risk of developing second primary cancers including the risk associated with primary histologic type (seminoma and non-seminoma) among testicular cancer survivors in Germany. We identified 16 990 and 1401 cases of testicular cancer in population-based cancer registries of East Germany (1961–1989 and 1996–2008) and Saarland (a federal state in West Germany; 1970–2008), respectively. We estimated the risk of a second primary cancer using standardized incidence ratios (SIRs) with 95% confidence intervals (95% CIs). To determine trends, we plotted model-based estimated annual SIRs. In East Germany, a total of 301 second primary cancers of any location were observed between 1961 and 1989 (SIR: 1.9; 95% CI: 1.7–2.1), and 159 cancers (any location) were observed between 1996 and 2008 (SIR: 1.7; 95% CI: 1.4–2.0). The SIRs for contralateral testicular cancer were increased in the registries with a range from 6.0 in Saarland to 13.9 in East Germany. The SIR for seminoma, in particular, was higher in East Germany compared to the other registries. We observed constant trends in the model-based SIRs for contralateral testicular cancers. The majority of reported SIRs of other cancer sites including histology-specific risks showed low precisions of estimated effects, likely due to small sample sizes. Testicular cancer patients are at increased risk especially for cancers of the contralateral testis and should receive intensive follow-ups. PMID:24407180

Reduced GABA{sub A} receptor density contralateral to a potentially epileptogenic MRI abnormality in a patient with complex partial seizures

Energy Technology Data Exchange (ETDEWEB)

Kuwert, T. [Dept. of Nuclear Medicine, Muenster Univ. (Germany); Stodieck, S.R.G. [Dept. of Neurology, Muenster Univ. (Germany); Puskas, C. [Dept. of Nuclear Medicine, Muenster Univ. (Germany); Diehl, B. [Dept. of Neurology, Muenster Univ. (Germany); Puskas, Z. [Inst. of Clinical Radiology, Muenster Univ. (Germany); Schuierer, G. [Inst. of Clinical Radiology, Muenster Univ. (Germany); Vollet, B. [Dept. of Nuclear Medicine, Muenster Univ. (Germany); Schober, O. [Dept. of Nuclear Medicine, Muenster Univ. (Germany)

1996-01-01

Imaging cerebral GABA{sub A} receptor density (GRD) with single-photon emission tomography (SPET) and iodine-123 iomazenil is highly accurate in lateralizing epileptogenic foci in patients with complex partial seizures of temporal origin. Limited knowledge exists on how iomazenil SPET compares with magnetic resonance imaging (MRI) in this regard. We present a patient with complex partial seizures in whom MRI had identified an arachnoid cyst anterior to the tip of the left temporal lobe. Contralaterally to this structural abnormality, interictal electroencephalography (EEG) performed after sleep deprivation disclosed an intermittent frontotemporal dysrhythmic focus with slow and sharp waves. On iomazenil SPET images GRD was significantly reduced in the right temporal lobe and thus contralaterally to the MRI abnormality, but ipsilaterally to the pathological EEG findings. These data suggest that iomazenil SPET may significantly contribute to the presurgical evaluation of epileptic patients even when MRI identifies potentialy epileptogenic structural lesions. (orig.)

Brain regions involved in voluntary movements as revealed by radioisotopic mapping of CBF or CMR-glucose changes

DEFF Research Database (Denmark)

Lassen, N A; Ingvar, D H

1990-01-01

Mapping of cortical and subcortical grey matter active during voluntary movements by means of measurements of local increases of CBF or CMR-Glucose is reviewed. Most of the studies concern observations in man during hand movements using the intracarotid Xenon-133 injection technique, an approach...... that only allows to image the cortex of the hemisphere on one side (the injected side) of the brain. The results show that simple static or repetitive movements mainly activate the contralateral primary hand area (MI and SI); complex preprogrammed or spontaneous purposeful movements the supplementary motor...... area SMA on both sides increase in CBF/CMR-glucose and even internally ("mentally") going through the trained movements, causes such changes; complex purposeful movements also activate the premotor cortex, a response that is bilateral with greatest response contralaterally. Studies in patients...

MEG reveals a fast pathway from somatosensory cortex to occipital areas via posterior parietal cortex in a blind subject

Directory of Open Access Journals (Sweden)

Andreas A Ioannides

2013-08-01

Full Text Available Cross-modal activity in visual cortex of blind subjects has been reported during performance of variety of non-visual tasks. A key unanswered question is through which pathways non-visual inputs are funneled to the visual cortex. Here we used tomographic analysis of single trial magnetoencephalography (MEG data recorded from one congenitally blind and two sighted subjects after stimulation of the left and right median nerves at three intensities: below sensory threshold, above sensory threshold and above motor threshold; the last sufficient to produce thumb twitching. We identified reproducible brain responses in the primary somatosensory (S1 and motor (M1 cortices at around 20 ms post-stimulus, which were very similar in sighted and blind subjects. Time-frequency analysis revealed strong 45 to 70 Hz activity at latencies of 20 to 50 ms in S1 and M1, and posterior parietal cortex Brodmann areas (BA 7 and 40, which compared to lower frequencies, were substantially more pronounced in the blind than the sighted subjects. Critically, at frequencies from α-band up to 100 Hz we found clear, strong and widespread responses in the visual cortex of the blind subject, which increased with the intensity of the somatosensory stimuli. Time-delayed mutual information (MI revealed that in blind subject the stimulus information is funneled from the early somatosensory to visual cortex through posterior parietal BA 7 and 40, projecting first to visual areas V5 and V3, and eventually V1. The flow of information through this pathway occured in stages characterized by convergence of activations into specific cortical regions. In sighted subjects, no linked activity was found that led from the somatosensory to the visual cortex through any of the studied brain regions. These results provide the first evidence from MEG that in blind subjects, tactile information is routed from primary somatosensory to occipital cortex via the posterior parietal cortex.

Transverse vs torsional ultrasound: prospective randomized contralaterally controlled study comparing two phacoemulsification-system handpieces.

Science.gov (United States)

Assil, Kerry K; Harris, Lindsay; Cecka, Jeannie

2015-01-01

To compare surgical efficiency and multiple early clinical outcome variables in eyes undergoing phacoemulsification using either transversal or torsional ultrasound systems. Assil Eye Institute, Beverly Hills, CA, USA. Prospective, randomized, clinician-masked, contralaterally controlled single-center evaluation. Patients seeking cataract removal in both eyes with implantation of multifocal intraocular lenses were randomly assigned to one of two treatment rooms for phacoemulsification with either a transverse ultrasound system or torsional handpiece system. The contralateral eye was treated at a later date with the alternate device. A total of 54 eyes of 27 patients having similar degrees of cataract, astigmatism, and visual potential were included. All operative data were collected for analysis, and patients were followed for 3 months after surgery. Similar visual acuity was reported at all postoperative visits between the two groups. Mean phacoemulsification time and total power required were both significantly lower with the transverse system than with the torsional technique (Ptransverse system vs torsional (Ptransverse vs torsional. Macular swelling was less at 1 week, 1 month, and 3 months with transverse vs torsional, although the difference did not achieve significance (P=0.1) at any single time point. Clinically detectable corneal edema was reported less frequently at all postoperative time points with the transverse system. The transverse ultrasound system was found to be possibly associated with less balanced salt-solution use, less phacoemulsification time, and less power required than the torsional phaco system. Postoperative data suggested that improved phaco efficiency may translate to a better overall safety profile for the patient.

Auditory Connections and Functions of Prefrontal Cortex

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Bethany ePlakke

2014-07-01

Full Text Available The functional auditory system extends from the ears to the frontal lobes with successively more complex functions occurring as one ascends the hierarchy of the nervous system. Several areas of the frontal lobe receive afferents from both early and late auditory processing regions within the temporal lobe. Afferents from the early part of the cortical auditory system, the auditory belt cortex, which are presumed to carry information regarding auditory features of sounds, project to only a few prefrontal regions and are most dense in the ventrolateral prefrontal cortex (VLPFC. In contrast, projections from the parabelt and the rostral superior temporal gyrus (STG most likely convey more complex information and target a larger, widespread region of the prefrontal cortex. Neuronal responses reflect these anatomical projections as some prefrontal neurons exhibit responses to features in acoustic stimuli, while other neurons display task-related responses. For example, recording studies in non-human primates indicate that VLPFC is responsive to complex sounds including vocalizations and that VLPFC neurons in area 12/47 respond to sounds with similar acoustic morphology. In contrast, neuronal responses during auditory working memory involve a wider region of the prefrontal cortex. In humans, the frontal lobe is involved in auditory detection, discrimination, and working memory. Past research suggests that dorsal and ventral subregions of the prefrontal cortex process different types of information with dorsal cortex processing spatial/visual information and ventral cortex processing non-spatial/auditory information. While this is apparent in the non-human primate and in some neuroimaging studies, most research in humans indicates that specific task conditions, stimuli or previous experience may bias the recruitment of specific prefrontal regions, suggesting a more flexible role for the frontal lobe during auditory cognition.

Auditory connections and functions of prefrontal cortex

Science.gov (United States)

Plakke, Bethany; Romanski, Lizabeth M.

2014-01-01

The functional auditory system extends from the ears to the frontal lobes with successively more complex functions occurring as one ascends the hierarchy of the nervous system. Several areas of the frontal lobe receive afferents from both early and late auditory processing regions within the temporal lobe. Afferents from the early part of the cortical auditory system, the auditory belt cortex, which are presumed to carry information regarding auditory features of sounds, project to only a few prefrontal regions and are most dense in the ventrolateral prefrontal cortex (VLPFC). In contrast, projections from the parabelt and the rostral superior temporal gyrus (STG) most likely convey more complex information and target a larger, widespread region of the prefrontal cortex. Neuronal responses reflect these anatomical projections as some prefrontal neurons exhibit responses to features in acoustic stimuli, while other neurons display task-related responses. For example, recording studies in non-human primates indicate that VLPFC is responsive to complex sounds including vocalizations and that VLPFC neurons in area 12/47 respond to sounds with similar acoustic morphology. In contrast, neuronal responses during auditory working memory involve a wider region of the prefrontal cortex. In humans, the frontal lobe is involved in auditory detection, discrimination, and working memory. Past research suggests that dorsal and ventral subregions of the prefrontal cortex process different types of information with dorsal cortex processing spatial/visual information and ventral cortex processing non-spatial/auditory information. While this is apparent in the non-human primate and in some neuroimaging studies, most research in humans indicates that specific task conditions, stimuli or previous experience may bias the recruitment of specific prefrontal regions, suggesting a more flexible role for the frontal lobe during auditory cognition. PMID:25100931

Kainate receptors in the rat hippocampus: A distribution and time course of changes in response to unilateral lesions of the entorhinal cortex

International Nuclear Information System (INIS)

Ulas, J.; Monaghan, D.T.; Cotman, C.W.

1990-01-01

The response of kainate receptors to deafferentation and subsequent reinnervation following unilateral entorhinal cortex lesions was studied in the rat hippocampus using quantitative in vitro autoradiography. The binding levels of [3H]kainic acid (KA) and changes in the distribution of KA sites were investigated in the dentate gyrus molecular layer (ML) and in various terminal zones in the CA1 field at 1, 3, 7, 14, 21, 30, and 60 d postlesion. The data from both the ipsilateral and contralateral hippocampus were compared with those from unoperated controls. The first changes in KA receptor distribution were observed 21 d postlesion when the dense band of KA receptors occupying the inner one-third of the ML expanded into the denervated outer two-thirds of the ipsilateral ML. The spreading of the KA receptor field into previously unoccupied zones continued 30 and 60 d postlesion. At these time points, the zone enriched in [3H]KA binding sites became significantly (on average 50%) wider than in unoperated controls. No changes were observed in either the distribution or binding levels in other hippocampal areas or in the contralateral hippocampus at any studied time point. Saturation analysis of binding in the ipsilateral ML 60 d postlesion revealed changes in the maximum number of receptor sites (Bmax) without changes in KA receptor affinity (Kd). The data suggest that the elevation of the [3H]KA binding in the outer two-thirds of the ML reflects an increase in the number of both low and high affinity receptor binding sites. The pattern of KA receptor redistribution was similar to the well-characterized pattern of sprouting of commissural/associational systems from the inner one-third into the outer two-thirds of the ML after entorhinal lesions

Connectivity changes underlying neurofeedback training of visual cortex activity.

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Frank Scharnowski

Full Text Available Neurofeedback based on real-time functional magnetic resonance imaging (fMRI is a new approach that allows training of voluntary control over regionally specific brain activity. However, the neural basis of successful neurofeedback learning remains poorly understood. Here, we assessed changes in effective brain connectivity associated with neurofeedback training of visual cortex activity. Using dynamic causal modeling (DCM, we found that training participants to increase visual cortex activity was associated with increased effective connectivity between the visual cortex and the superior parietal lobe. Specifically, participants who learned to control activity in their visual cortex showed increased top-down control of the superior parietal lobe over the visual cortex, and at the same time reduced bottom-up processing. These results are consistent with efficient employment of top-down visual attention and imagery, which were the cognitive strategies used by participants to increase their visual cortex activity.

Pathologic implications of severely stenotic carotid artery in disparity to the contralateral asymptomatic artery

International Nuclear Information System (INIS)

Cacayorin, E.D.; Schwartz, R.A.; Park, S.H.

1989-01-01

In 15 patients (eight women, seven men; age range 56-67 years), arteriography showed severely stenotic internal carotid artery in contrast to the contralateral asymptomatic carotid artery. The patients with recent neurologic manifestations of transient ischemic attack and amaurosis fugax underwent carotid endarterectomy and were subsequently proved to have hemorrhagic atheromatous plaques on gross and histologic examinations. The disparity was unusually significant: 80%-95% stenosis for the symptomatic side, and 0%-20% stenosis for the asymptomatic side. The authors conclude that this arteriographic finding suggests high likelihood of focal subintimal hemorrhage occurring locally; such pathologic change might actually precipitate a cerebroembolic event

Lesions of entorhinal cortex produce a calpain-mediated degradation of brain spectrin in dentate gyrus. I. Biochemical studies.

Science.gov (United States)

Seubert, P; Ivy, G; Larson, J; Lee, J; Shahi, K; Baudry, M; Lynch, G

1988-09-06

Lesions of the rat entorhinal cortex cause extensive synaptic restructuring and perturbation of calcium regulation in the dentate gyrus of hippocampus. Calpain is a calcium-activated protease which has been implicated in degenerative phenomena in muscles and in peripheral nerves. In addition, calpain degrades several major structural neuronal proteins and has been proposed to play a critical role in the morphological changes observed following deafferentation. In this report we present evidence that lesions of the entorhinal cortex produce a marked increase in the breakdown of brain spectrin, a substrate for calpain, in the dentate gyrus. Two lines of evidence indicate that this effect is due to calpain activation: (i) the spectrin breakdown products observed following the lesion are indistinguishable from calpain-generated spectrin fragments in vitro; and (ii) their appearance can be reduced by prior intraventricular in fusion of leupeptin, a calpain inhibitor. Levels of spectrin breakdown products are increased as early as 4 h post-lesion, reach maximal values at 2 days, and remain above normal to some degree for at least 27 days. In addition, a small but significant increase in spectrin proteolysis is also observed in the hippocampus contralateral to the lesioned side in the first week postlesion. At 2 days postlesion the total spectrin immunoreactivity (native polypeptide plus breakdown products) increases by 40%, suggesting that denervation of the dentate gyrus produces not only an increased rate of spectrin degradation but also an increased rate of spectrin synthesis. These results indicate that calpain activation and spectrin degradation are early biochemical events following deafferentation and might well participate in the remodelling of postsynaptic structures. Finally, the magnitude of the observed effects as well as the stable nature of the breakdown products provide a sensitive assay for neuronal pathology.

Shrinkage of ipsilateral taste buds and hyperplasia of contralateral taste buds following chorda tympani nerve transection

OpenAIRE

Li, Yi-ke; Yang, Juan-mei; Huang, Yi-bo; Ren, Dong-dong; Chi, Fang-lu

2015-01-01

The morphological changes that occur in the taste buds after denervation are not well understood in rats, especially in the contralateral tongue epithelium. In this study, we investigated the time course of morphological changes in the taste buds following unilateral nerve transection. The role of the trigeminal component of the lingual nerve in maintaining the structural integrity of the taste buds was also examined. Twenty-four Sprague-Dawley rats were randomly divided into three groups: co...

Spontaneous Transient Lateral Thoracic Lung Herniation Resulting in Systemic Inflammatory Response Syndrome (SIRS and Subsequent Contralateral Lung Injury

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Antony Kaliyadan

2011-01-01

Full Text Available Lung herniation is a relatively rare clinical entity that is most commonly either congenital or acquired traumatically. We describe a case of spontaneous lung herniation secondary to acute cough in an obese male smoker complicated by contralateral acute lung injury and systemic inflammatory response syndrome (SIRS. Mechanisms of lung herniation, classification, diagnosis, and management will be discussed.

Trunk Muscle Function Deficit in Youth Baseball Pitchers With Excessive Contralateral Trunk Tilt During Pitching.

Science.gov (United States)

Oyama, Sakiko; Waldhelm, Andrew G; Sosa, Araceli R; Patel, Ravina R; Kalinowski, Derick L

2017-09-01

Pitching technique is one of many factors that affect injury risk. Exhibiting excessive contralateral trunk tilt (CLT) during pitching has been linked to higher ball speed but also to increased joint loading. Deficit in trunk muscle strength has been suggested as an underlying cause of this movement pattern. The purpose of the study was to compare trunk muscle strength between youth baseball pitchers with varying degree of CLT during pitching. Cross-sectional study. Baseball practice fields. Twenty-eight youth baseball pitchers. Pitching technique was captured using a video camera. Based on the 2-dimensional trunk contralateral flexion angle, pitchers were categorized into low (30 degrees) CLT groups. Maximum isometric strength tests for trunk flexion, extension, and bilateral rotation, measured using a dynamometer. The pitchers with high CLT (n = 10) had longer pitching experience (P = 0.014), produced higher ball speed (P = 0.003) compared with the pitchers with moderate (n = 10) and low (n = 8) CLT, but demonstrated greater asymmetry in trunk rotation strength (relative weakness in rotation strength toward dominant side) compared with the pitchers with low CLT (P = 0.015). Excessive CLT may be a strategy that young pitchers learn to achieve higher ball velocity but also may be associated with imbalance between the oblique muscles on dominant and nondominant side, which may be acquired from repetitive pitching. Strengthening and emphasizing the use of dominant side oblique muscles may keep pitchers from leaning excessively during pitching and thus decrease joint loading.

Unilateral hearing during development: hemispheric specificity in plastic reorganizations.

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Kral, Andrej; Heid, Silvia; Hubka, Peter; Tillein, Jochen

2013-01-01

The present study investigates the hemispheric contributions of neuronal reorganization following early single-sided hearing (unilateral deafness). The experiments were performed on ten cats from our colony of deaf white cats. Two were identified in early hearing screening as unilaterally congenitally deaf. The remaining eight were bilaterally congenitally deaf, unilaterally implanted at different ages with a cochlear implant. Implanted animals were chronically stimulated using a single-channel portable signal processor for two to five months. Microelectrode recordings were performed at the primary auditory cortex under stimulation at the hearing and deaf ear with bilateral cochlear implants. Local field potentials (LFPs) were compared at the cortex ipsilateral and contralateral to the hearing ear. The focus of the study was on the morphology and the onset latency of the LFPs. With respect to morphology of LFPs, pronounced hemisphere-specific effects were observed. Morphology of amplitude-normalized LFPs for stimulation of the deaf and the hearing ear was similar for responses recorded at the same hemisphere. However, when comparisons were performed between the hemispheres, the morphology was more dissimilar even though the same ear was stimulated. This demonstrates hemispheric specificity of some cortical adaptations irrespective of the ear stimulated. The results suggest a specific adaptation process at the hemisphere ipsilateral to the hearing ear, involving specific (down-regulated inhibitory) mechanisms not found in the contralateral hemisphere. Finally, onset latencies revealed that the sensitive period for the cortex ipsilateral to the hearing ear is shorter than that for the contralateral cortex. Unilateral hearing experience leads to a functionally-asymmetric brain with different neuronal reorganizations and different sensitive periods involved.

Cell-Specific Cholinergic Modulation of Excitability of Layer 5B Principal Neurons in Mouse Auditory Cortex

Science.gov (United States)

Joshi, Ankur; Kalappa, Bopanna I.; Anderson, Charles T.

2016-01-01

The neuromodulator acetylcholine (ACh) is crucial for several cognitive functions, such as perception, attention, and learning and memory. Whereas, in most cases, the cellular circuits or the specific neurons via which ACh exerts its cognitive effects remain unknown, it is known that auditory cortex (AC) neurons projecting from layer 5B (L5B) to the inferior colliculus, corticocollicular neurons, are required for cholinergic-mediated relearning of sound localization after occlusion of one ear. Therefore, elucidation of the effects of ACh on the excitability of corticocollicular neurons will bridge the cell-specific and cognitive properties of ACh. Because AC L5B contains another class of neurons that project to the contralateral cortex, corticocallosal neurons, to identify the cell-specific mechanisms that enable corticocollicular neurons to participate in sound localization relearning, we investigated the effects of ACh release on both L5B corticocallosal and corticocollicular neurons. Using in vitro electrophysiology and optogenetics in mouse brain slices, we found that ACh generated nicotinic ACh receptor (nAChR)-mediated depolarizing potentials and muscarinic ACh receptor (mAChR)-mediated hyperpolarizing potentials in AC L5B corticocallosal neurons. In corticocollicular neurons, ACh release also generated nAChR-mediated depolarizing potentials. However, in contrast to the mAChR-mediated hyperpolarizing potentials in corticocallosal neurons, ACh generated prolonged mAChR-mediated depolarizing potentials in corticocollicular neurons. These prolonged depolarizing potentials generated persistent firing in corticocollicular neurons, whereas corticocallosal neurons lacking mAChR-mediated depolarizing potentials did not show persistent firing. We propose that ACh-mediated persistent firing in corticocollicular neurons may represent a critical mechanism required for learning-induced plasticity in AC. SIGNIFICANCE STATEMENT Acetylcholine (ACh) is crucial for cognitive

Dynamic Modulation of Sensory Cortex by Top-Down Spatial Attention

Science.gov (United States)

2015-04-15

Farwell LA, Donchin E (1988) Talking off the top of your head: toward a mental prosthesis utilizing event-related brain potentials...analyzed our switching conditions independently, we feel the resultant ipsilateral/contralateral signals are sufficiently similar in their gross

Shrinkage of ipsilateral taste buds and hyperplasia of contralateral taste buds following chorda tympani nerve transection.

Science.gov (United States)

Li, Yi-Ke; Yang, Juan-Mei; Huang, Yi-Bo; Ren, Dong-Dong; Chi, Fang-Lu

2015-06-01

The morphological changes that occur in the taste buds after denervation are not well understood in rats, especially in the contralateral tongue epithelium. In this study, we investigated the time course of morphological changes in the taste buds following unilateral nerve transection. The role of the trigeminal component of the lingual nerve in maintaining the structural integrity of the taste buds was also examined. Twenty-four Sprague-Dawley rats were randomly divided into three groups: control, unilateral chorda tympani nerve transection and unilateral chorda tympani nerve transection + lingual nerve transection. Rats were allowed up to 42 days of recovery before being euthanized. The taste buds were visualized using a cytokeratin 8 antibody. Taste bud counts, volumes and taste receptor cell numbers were quantified and compared among groups. No significant difference was detected between the chorda tympani nerve transection and chorda tympani nerve transection + lingual nerve transection groups. Taste bud counts, volumes and taste receptor cell numbers on the ipsilateral side all decreased significantly compared with control. On the contralateral side, the number of taste buds remained unchanged over time, but they were larger, and taste receptor cells were more numerous postoperatively. There was no evidence for a role of the trigeminal branch of the lingual nerve in maintaining the structural integrity of the anterior taste buds.

Shrinkage of ipsilateral taste buds and hyperplasia of contralateral taste buds following chorda tympani nerve transection

Directory of Open Access Journals (Sweden)

Yi-ke Li

2015-01-01

Full Text Available The morphological changes that occur in the taste buds after denervation are not well understood in rats, especially in the contralateral tongue epithelium. In this study, we investigated the time course of morphological changes in the taste buds following unilateral nerve transection. The role of the trigeminal component of the lingual nerve in maintaining the structural integrity of the taste buds was also examined. Twenty-four Sprague-Dawley rats were randomly divided into three groups: control, unilateral chorda tympani nerve transection and unilateral chorda tympani nerve transection + lingual nerve transection. Rats were allowed up to 42 days of recovery before being euthanized. The taste buds were visualized using a cytokeratin 8 antibody. Taste bud counts, volumes and taste receptor cell numbers were quantified and compared among groups. No significant difference was detected between the chorda tympani nerve transection and chorda tympani nerve transection + lingual nerve transection groups. Taste bud counts, volumes and taste receptor cell numbers on the ipsilateral side all decreased significantly compared with control. On the contralateral side, the number of taste buds remained unchanged over time, but they were larger, and taste receptor cells were more numerous postoperatively. There was no evidence for a role of the trigeminal branch of the lingual nerve in maintaining the structural integrity of the anterior taste buds.

Distribution of catecholamines and serotonin in the rat cerebral cortex:

International Nuclear Information System (INIS)

Reader, T.A.

1981-01-01

The rat cerebral cortex was dissected in five regions and analyzed for the catecholamines noradrenaline, adrenaline and dopamine, and for the indoleamine seroton in using sensitive radioenzymatic assay methods with thin-layer-chromatography. The noradrenaline concentration was highest in the ventral cortex, lateral to the hypothalamus, had intermediate values for the prefrontal, frontal and parietal cortical areas and was lowest in the occipital cortex. Dopamine levels were also highest in the cortex lateral to the hypothalamus, and moderate in the prefrontal and frontal cortical areas, with the lowest values measured for the occipital cortex. The ratios dopamine/noradrenaline further support the hypothesis that they are independent transmitters. Traces of adrenaline were measured in all regions examined. The serotonin distribution was found to be non-homogeneous, with the highest values for the prefrontal cortex and ventral cortex lateral to the hypothalamus. The functional significance of these amines and their ratios are discussed in relation to their role as putative modulators of cortical neuronal excitability. (author)

Convergence of ipsi- and contralateral muscle afferents on common interneurons mediating reciprocal inhibition of ankle plantarflexors in humans

DEFF Research Database (Denmark)

Mrachacz-Kersting, Natalie; Geertsen, Svend S.; Stevenson, Andrew James Thomas

2017-01-01

reciprocal Ia inhibition of the opposite limb. This study was designed to investigate whether this pathway is similar in humans to that described in animals. Thirteen healthy volunteers participated in one of two experiments. In experiment 1, the effects of ipsilateral posterior tibial nerve (i......PTN) stimulation were assessed on the reciprocal Ia inhibition of the contralateral soleus (cSOL) motoneuronal pool (n = 8). Across all participants, iPTN stimulation intensity was 1.69 ± 0.3 × Motor Threshold (MT) and contralateral common peroneal (cCPN) stimulation intensity was 0.86 ± 0.16 × MT. iPTN and c...... used during the H-reflex conditioning experiment were 1.79 ± 0.4 × MT for the iPTN stimulation and 0.88 ± 0.16 × MT for cCPN stimulation. Across all participants, the onset of the cSOL EMG suppression was 42 ± 4, 44 ± 3 and 44 ± 3 ms for iPTN, cCPN and iPTN + cCPN conditions, respectively...

Metástasis cervical contralateral en el carcinoma epidermoide de la cavidad oral: Estudio clínico analítico retrospectivo en 315 pacientes primariamente tratados con cirugía Contralateral neck metastasis in squamous cell carcinoma of the oral cavity: An analytical retrospective clinical study of 315 patients primarily treated with surgery

Directory of Open Access Journals (Sweden)

R. González-García

2008-06-01

Full Text Available Objetivos. Existen en la literatura numerosos estudios en relación con los factores pronósticos implicados en la aparición de metástasis cervicales ipsilaterales en el carcinoma epidermoide de cavidad oral. Sin embargo, no existen estudios clínicos amplios acerca de la asociación de factores clínico-patológicos y la aparición de metástasis cervicales contralaterales tras la resección quirúrgica del tumor primario. El propósito de este estudio es el análisis de los factores implicados en la aparición de metástasis cervical contralateral en pacientes con carcinoma epidermoide de cavidad oral primariamente tratados con cirugía. Pacientes y métodos. Se analizó una serie de 315 pacientes consecutivos con carcinoma epidermoide de la cavidad oral no tratados previamente. Se realizó un estudio complementario del subgrupo de 203 pacientes con carcinoma epidermoide del borde lateral de la lengua libre, por tratarse de un grupo muy prevalente en la serie analizada. Todos los pacientes recibieron tratamiento quirúrgico con o sin tratamiento radioterápico adyuvante. Varias fueron las variables clínicas e histopatológicas analizadas, como son: las características clínicas del tumor, el estadio tumoral, el grado de diferenciación histológica, el tipo de disección cervical, la supervivencia enfermedad- específica, los márgenes quirúrgicos en la pieza resecada, la extensión ganglionar extracapsular, la diseminación perineural y la afectación ósea. Resultados. La duración media del seguimiento de los pacientes que sobrevivieron fue de 70,9 ± 49,6 meses. Ochenta y tres pacientes murieron a causa de la enfermedad a lo largo del seguimiento. Cuarenta y siete de estos pertenecían al subgrupo de pacientes con carcinoma epidermoide de lengua. Un total de 147 pacientes permanecía vivo sin evidencias de recurrencia de la enfermedad al final del periodo de seguimiento, 116 de los cuales correspondían al subgrupo de pacientes con

Beta activity in the premotor cortex is increased during stabilized as compared to normal walking

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Sjoerd M. Bruijn

2015-10-01

Full Text Available Walking on two legs is inherently unstable. Still, we humans perform remarkable well at it, mostly without falling. To gain more understanding of the role of the brain in controlling gait stability we measured brain activity using electro-encephalography (EEG during stabilized and normal walking.Subjects walked on a treadmill in two conditions, each lasting 10 minutes; normal, and while being laterally stabilized by elastic cords. Kinematics of trunk and feet, electro-myography (EMG of neck muscles, as well as 64-channel EEG were recorded. To assess gait stability the local divergence exponent, step width, and trunk range of motion were calculated from the kinematic data. We used independent component analysis to remove movement, EMG, and eyeblink artifacts from the EEG, after which dynamic imaging of coherent sources beamformers were determined to identify cortical sources that showed a significant difference between conditions. Stabilized walking led to a significant increase in gait stability, i.e. lower local divergence exponents. Beamforming analysis of the beta band activity revealed significant sources in bilateral pre-motor cortices. Projection of sensor data on these sources showed a significant difference only in the left premotor area, with higher beta power during stabilized walking, specifically around push-off, although only significant around contralateral push-off. It appears that even during steady gait the cortex is involved in the control of stability.

The correlation of background parenchymal enhancement in the contralateral breast with patient and tumor characteristics of MRI-screen detected breast cancers.

Science.gov (United States)

Vreemann, Suzan; Gubern-Mérida, Albert; Borelli, Cristina; Bult, Peter; Karssemeijer, Nico; Mann, Ritse M

2018-01-01

Higher background parenchymal enhancement (BPE) could be used for stratification of MRI screening programs since it might be related to a higher breast cancer risk. Therefore, the purpose of this study is to correlate BPE to patient and tumor characteristics in women with unilateral MRI-screen detected breast cancer who participated in an intermediate and high risk screening program. As BPE in the affected breast may be difficult to discern from enhancing cancer, we assumed that BPE in the contralateral breast is a representative measure for BPE in women with unilateral breast cancer. This retrospective study was approved by our local institutional board and a waiver for consent was granted. MR-examinations of women with unilateral breast cancers screen-detected on breast MRI were evaluated by two readers. BPE in the contralateral breast was rated according to BI-RADS. Univariate analyses were performed to study associations. Observer variability was computed. Analysis included 77 breast cancers in 76 patients (age: 48±9.8 years), including 62 invasive and 15 pure ductal carcinoma in-situ cases. A negative association between BPE and tumor grade (p≤0.016) and a positive association with progesterone status (p≤0.021) was found. The correlation was stronger when only considering invasive disease. Inter-reader agreement was substantial. Lower BPE in the contralateral breast in women with unilateral breast cancer might be associated to higher tumor grade and progesterone receptor negativity. Great care should be taken using BPE for stratification of patients to tailored screening programs.

Probing the Effects and Mechanisms of Electroacupuncture at Ipsilateral or Contralateral ST36–ST37 Acupoints on CFA-induced Inflammatory Pain

Science.gov (United States)

Lu, Kung-Wen; Hsu, Chao-Kuei; Hsieh, Ching-Liang; Yang, Jun; Lin, Yi-Wen

2016-01-01

Transient receptor potential vanilloid 1 (TRPV1) and associated signaling pathways have been reported to be increased in inflammatory pain signaling. There are accumulating evidences surrounding the therapeutic effect of electroacupuncture (EA). EA can reliably attenuate the increase of TRPV1 in mouse inflammatory pain models with unclear signaling mechanisms. Moreover, the difference in the clinical therapeutic effects between using the contralateral and ipsilateral acupoints has been rarely studied. We found that inflammatory pain, which was induced by injecting the complete Freund’s adjuvant (CFA), (2.14 ± 0.1, p < 0.05, n = 8) can be alleviated after EA treatment at either ipsilateral (3.91 ± 0.21, p < 0.05, n = 8) or contralateral acupoints (3.79 ± 0.25, p < 0.05, n = 8). EA may also reduce nociceptive Nav sodium currents in dorsal root ganglion (DRG) neurons. The expression of TRPV1 and associated signaling pathways notably increased after the CFA injection; this expression can be further attenuated significantly in EA treatment. TRPV1 and associated signaling pathways can be prevented in TRPV1 knockout mice, suggesting that TRPV1 knockout mice are resistant to inflammatory pain. Through this study, we have increased the understanding of the mechanism that both ipsilateral and contralateral EA might alter TRPV1 and associated signaling pathways to reduce inflammatory pain. PMID:26906464

More target features in visual working memory leads to poorer search guidance: Evidence from contralateral delay activity

OpenAIRE

Schmidt, Joseph; MacNamara, Annmarie; Proudfit, Greg Hajcak; Zelinsky, Gregory J.

2014-01-01

The visual-search literature has assumed that the top-down target representation used to guide search resides in visual working memory (VWM). We directly tested this assumption using contralateral delay activity (CDA) to estimate the VWM load imposed by the target representation. In Experiment 1, observers previewed four photorealistic objects and were cued to remember the two objects appearing to the left or right of central fixation; Experiment 2 was identical except that observers previewe...

Correlation of Respiratory Activity of Contralateral Diaphragm Muscles for Evaluation of Recovery Following Hemiparesis

Science.gov (United States)

Dow, Douglas E.; Zhan, Wen-Zhi; Sieck, Gary C.; Mantilla, Carlos B.

2014-01-01

Respiration is impaired by disruption of the central drive for inspiration to the diaphragm muscle (DIAm). Some function may recover involving nerve regeneration, reinnervation or neuroplasticity. A research animal model involves inducing hemiparesis of the DIAm and monitoring any recovery under different conditions. Methods to accurately track the level of functional recovery are needed. In this study, an algorithm was developed and tested to quantify the relative amount of electromyogram (EMG) activity that temporally correlated for an experimental (EXP) hemi-DIAm with its intact contralateral hemi-DIAm. An average rectified value (ARV) trace was calculated. A template was formed of the ARV trace of the intact hemi-DIAm, with higher positive values corresponding with periods of inspirations and lower negative values corresponding with quiet periods. This template was multiplied by the EXP ARV trace to reward (more positive) periods of correlating activity, and punish (more negative) periods of high activity on the EXP side that corresponded with quiet periods on the intact side. The average integrated value was the index of correlating contralateral activity (ICCA). A negative ICCA value indicated no net correlation of activity, and a positive value indicated a net correlation of activity. The algorithm was tested on rats having the conditions of control or hemi-paresis induced by denervatation (DNV), tetrodotoxin administration (TTX) or cervical spinal hemi-section (SH). Control had high positive ICCA values, and DNV had negative values. TTX maintained negative ICCA values at 3, 7 and 14 days, indicating a lack of functional recovery. SH maintained negative values at 3 and 7 days, but a subset had positive values at 14 days indicating some functional recovery. PMID:19965125

Brain activity during bilateral rapid alternate finger tapping measured with magnetoencephalography

Science.gov (United States)

Fukuda, Hiroshi; Odagaki, Masato; Hiwaki, Osamu; Kodabashi, Atsushi; Fujimoto, Toshiro

2009-04-01

Using magnetoencephalography (MEG), brain regions involved in an alternate bimanual tapping task by index fingers triggered with spontaneous timing were investigated. The tapping mode in which both index fingers moved simultaneously was interlaced during the task. The groups of the alternate tapping (AL mode) and the simultaneous tapping (SI mode) were extracted from the successive alternating taps with a histogram of intervals between the right and left index fingers. MEG signals in each mode were averaged separately before and after the tapping initiation of the dominant index finger. The activities of the contralateral sensorimotor cortex before and after the tapping initiation in the AL mode were larger than that in the SI mode. The result indicates that the activity of the contralateral sensorimotor cortex depends on the degree of achievement in the difficult motor task such as the voluntary alternate tapping movements.

Spatiotopic coding of BOLD signal in human visual cortex depends on spatial attention.

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Sofia Crespi

Full Text Available The neural substrate of the phenomenological experience of a stable visual world remains obscure. One possible mechanism would be to construct spatiotopic neural maps where the response is selective to the position of the stimulus in external space, rather than to retinal eccentricities, but evidence for these maps has been inconsistent. Here we show, with fMRI, that when human subjects perform concomitantly a demanding attentive task on stimuli displayed at the fovea, BOLD responses evoked by moving stimuli irrelevant to the task were mostly tuned in retinotopic coordinates. However, under more unconstrained conditions, where subjects could attend easily to the motion stimuli, BOLD responses were tuned not in retinal but in external coordinates (spatiotopic selectivity in many visual areas, including MT, MST, LO and V6, agreeing with our previous fMRI study. These results indicate that spatial attention may play an important role in mediating spatiotopic selectivity.

Functional Magnetic Resonance Imaging in the Presurgical Evaluation of Brain Vascular Malformations

International Nuclear Information System (INIS)

Montes, Natalia; Herrera, Diego A; Vargas Sergio A

2010-01-01

Objective: To describe our experience in presurgical evaluation of intracranial vascular malformations by means of functional magnetic resonance (fMRI). Method: To evaluate eight patients with cerebral vascular malformations (seven arterio-venous malformation [AVM ] and one cavernous malformation) to send to the eloquent cortex with RMf pre-surgical mapping is assessed. Used a technique that is dependent on the level of oxygen (BOLD) to locate these areas in the cerebral vascular malformation, by applying different paradigms. Results: We found one AVM at the right temporal lobe with activation of the parahipocampal gyrus at the contralateral side using a memory paradigm; another patient with an AVM at the right mesotemporal lobe showed activation of visual and spatial memory of the contralateral hippocampus and parahippocampus. One patient with an AVM at the left parietal lobe without compromise of sensorial and motor cortex; a cavernous malformation at the left angular gyrus with hemispheric language dominance in that side; one right thalamic AVM, one periventricular AVM bilateral language dominance; one left occipital AVM with decreased activation in visual association cortex; one temporoccipital AVM with left language dominance and neurovascular uncoupling. Conclusion: fMRI can delineate anatomically the relationship between the lesion and eloquent cortex, providing useful information for presurgical planning and allowing risk estimation of intervention.

Entorhinal Cortex: Antemortem Cortical Thickness and Postmortem Neurofibrillary Tangles and Amyloid Pathology.

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Thaker, A A; Weinberg, B D; Dillon, W P; Hess, C P; Cabral, H J; Fleischman, D A; Leurgans, S E; Bennett, D A; Hyman, B T; Albert, M S; Killiany, R J; Fischl, B; Dale, A M; Desikan, R S

2017-05-01

The entorhinal cortex, a critical gateway between the neocortex and hippocampus, is one of the earliest regions affected by Alzheimer disease-associated neurofibrillary tangle pathology. Although our prior work has automatically delineated an MR imaging-based measure of the entorhinal cortex, whether antemortem entorhinal cortex thickness is associated with postmortem tangle burden within the entorhinal cortex is still unknown. Our objective was to evaluate the relationship between antemortem MRI measures of entorhinal cortex thickness and postmortem neuropathological measures. We evaluated 50 participants from the Rush Memory and Aging Project with antemortem structural T1-weighted MR imaging and postmortem neuropathologic assessments. Here, we focused on thickness within the entorhinal cortex as anatomically defined by our previously developed MR imaging parcellation system (Desikan-Killiany Atlas in FreeSurfer). Using linear regression, we evaluated the association between entorhinal cortex thickness and tangles and amyloid-β load within the entorhinal cortex and medial temporal and neocortical regions. We found a significant relationship between antemortem entorhinal cortex thickness and entorhinal cortex ( P = .006) and medial temporal lobe tangles ( P = .002); we found no relationship between entorhinal cortex thickness and entorhinal cortex ( P = .09) and medial temporal lobe amyloid-β ( P = .09). We also found a significant association between entorhinal cortex thickness and cortical tangles ( P = .003) and amyloid-β ( P = .01). We found no relationship between parahippocampal gyrus thickness and entorhinal cortex ( P = .31) and medial temporal lobe tangles ( P = .051). Our findings indicate that entorhinal cortex-associated in vivo cortical thinning may represent a marker of postmortem medial temporal and neocortical Alzheimer disease pathology. © 2017 by American Journal of Neuroradiology.

Effects of Arousal on Mouse Sensory Cortex Depend on Modality

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Daisuke Shimaoka

2018-03-01

Full Text Available Summary: Changes in arousal modulate the activity of mouse sensory cortex, but studies in different mice and different sensory areas disagree on whether this modulation enhances or suppresses activity. We measured this modulation simultaneously in multiple cortical areas by imaging mice expressing voltage-sensitive fluorescent proteins (VSFP. VSFP imaging estimates local membrane potential across large portions of cortex. We used temporal filters to predict local potential from running speed or from pupil dilation, two measures of arousal. The filters provided good fits and revealed that the effects of arousal depend on modality. In the primary visual cortex (V1 and auditory cortex (Au, arousal caused depolarization followed by hyperpolarization. In the barrel cortex (S1b and a secondary visual area (LM, it caused only hyperpolarization. In all areas, nonetheless, arousal reduced the phasic responses to trains of sensory stimuli. These results demonstrate diverse effects of arousal across sensory cortex but similar effects on sensory responses. : Shimaoka et al. use voltage-sensitive imaging to show that the effects of arousal on the mouse cortex are markedly different across areas and over time. In all the sensory areas studied, nonetheless, arousal reduced the phasic voltage responses to trains of sensory stimuli. Keywords: cerebral cortex, cortical state, locomotion, sensory processing, widefield imaging

Magnetic Resonance Imaging based Cartilage Loss in Painful Contra-Lateral Knees with and without Radiographic Joint Space Narrowing – Data from the Osteoarthritis Initiative (OAI)

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Eckstein, Felix; Benichou, Olivier; Wirth, Wolfgang; Nelson, David R; Maschek, Susanne; Hudelmaier, Martin; Kwoh, C. Kent; Guermazi, Ali; Hunter, David

2010-01-01

Objective Magnetic resonance imaging (MRI) was used to assess whether knees with advanced radiographic disease (medial joint space narrowing = mJSN) encounter greater longitudinal cartilage loss than contra-lateral knees with earlier disease (no or less mJSN). Methods Participants were selected from 2678 cases in the Osteoarthritis Initiative, based on exhibition of bilateral pain, BMI>25, mJSN in one knee, no or less mJSN in the contra-lateral knee, and no lateral JSN in both knees. 80 participants (age 60.6±9.1 yrs) fulfilled these criteria. Medial tibial and femoral cartilage morphology was analyzed from baseline and 1-year follow-up sagittal DESSwe 3 Tesla MRI of both knees, by experienced readers blinded to the timepoint and mJSN status. Results Knees with more radiographic mJSN displayed greater medial cartilage loss (-80 μm), assessed by MRI, than contra-lateral knees with less mJSN (-57μm). The difference reached statistical significance in participants with mJSN grade 2 or 3 (p=0.005 to p=0.08), but not in participants with mJSN grade 1 (p=0.28 to 0.98). In knees with more mJSN, cartilage loss increased with higher grades of mJSN (p=0.003 in the medial femur). Knees with mJSN grade 2 or 3 displayed greater cartilage loss in the weight-bearing medial femur than in the posterior femur or in the medial tibia (p=0.048). Conclusion Knees with advanced mJSN displayed greater cartilage loss than contra-lateral knees with less mJSN. These data suggest that radiography can be used to stratify fast structural progressors, and that MRI cartilage thickness loss is more pronounced at advanced radiographic disease stage. PMID:19714595

TMS-induced neural noise in sensory cortex interferes with short-term memory storage in prefrontal cortex

OpenAIRE

Bancroft, Tyler D.; Hogeveen, Jeremy; Hockley, William E.; Servos, Philip

2014-01-01

In a previous study, Harris et al. (2002) found disruption of vibrotactile short-term memory after applying single-pulse transcranial magnetic stimulation (TMS) to primary somatosensory cortex (SI) early in the maintenance period, and suggested that this demonstrated a role for SI in vibrotactile memory storage. While such a role is compatible with recent suggestions that sensory cortex is the storage substrate for working memory, it stands in contrast to a relatively large body of evidence f...

The significance of memory in sensory cortex

OpenAIRE

Muckli, Lars; Petro, Lucy S.

2017-01-01

Early sensory cortex is typically investigated in response to sensory stimulation, masking the contribution of internal signals. Recently, van Kerkoerle and colleagues reported that attention and memory signals segregate from sensory signals within specific layers of primary visual cortex, providing insight into the role of internal signals in sensory processing.

Probing the Effects and Mechanisms of Electroacupuncture at Ipsilateral or Contralateral ST36-ST37 Acupoints on CFA-induced Inflammatory Pain.

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Lu, Kung-Wen; Hsu, Chao-Kuei; Hsieh, Ching-Liang; Yang, Jun; Lin, Yi-Wen

2016-02-24

Transient receptor potential vanilloid 1 (TRPV1) and associated signaling pathways have been reported to be increased in inflammatory pain signaling. There are accumulating evidences surrounding the therapeutic effect of electroacupuncture (EA). EA can reliably attenuate the increase of TRPV1 in mouse inflammatory pain models with unclear signaling mechanisms. Moreover, the difference in the clinical therapeutic effects between using the contralateral and ipsilateral acupoints has been rarely studied. We found that inflammatory pain, which was induced by injecting the complete Freund's adjuvant (CFA), (2.14 ± 0.1, p CFA injection; this expression can be further attenuated significantly in EA treatment. TRPV1 and associated signaling pathways can be prevented in TRPV1 knockout mice, suggesting that TRPV1 knockout mice are resistant to inflammatory pain. Through this study, we have increased the understanding of the mechanism that both ipsilateral and contralateral EA might alter TRPV1 and associated signaling pathways to reduce inflammatory pain.

[Contralateral Recession of the Inferior Oblique Muscle in Grave's Disease Patients with Mild M. rectus inferior fibrosis].

Science.gov (United States)

Eckstein, A; Raczynski, S; Dekowski, D; Esser, J

2015-10-01

The aim of this study was to evaluate the dose effect and the resulting binocular single vision for inferior oblique muscle recession in patients with Grave's orbitopathy. The evaluation covered all patients (n = 13) between 2010-2013 treated with recession of the inferior oblique muscle for vertical deviation caused by inferior fibrosis of the contralateral eye. The inclusion criterion was a small vertical squint angle with excyclotorsion. The corrected vertical squint angle was 3.75° [7 pdpt] (median, min 1.5° [3 pdpt], max 8° [16 pdpt]) in primary position and 5.5° in adduction [11pdpt] (median, min 3°[6 pdpt], max 9°[18pdpt]). Excyclotorsion was 4° [8 pdpt] (median, min 1° [2 pdpt], max 9° [18 pdpt]). Elevation was only slightly impaired and the side difference was 5° (median). The recession distance was preoperatively determined: 0.5° squint angle reduction per mm recession distance (calculation from patients who received surgery before 2010). Inferior oblique recession generated a good field of binocular single vision (BSV) for all patients. All patients reached BSV in the central area (20°) and within 30° of downgaze. Sixty nine percent of the patients were completely diplopia free in downgaze. Diplopia persisted in more than half of the patients in up gaze outside 15°. Squint reduction was 0.5° [1 pdpt] [0.45-0.67]/per mm recession distance in primary position and 0.65° [1.3 pdpt] [0.55-0.76]/per mm for the vertical deviation in adduction. Excyclotorsion was reduced to ≤ 2° in 77 % of the patients. Inferior oblique muscle recession can be very successfully performed on the contralateral eye in patients with mild inferior rectus muscle fibrosis. Surgery at the contralateral yoke muscle prevents the risk of overeffect with resulting diplopia in downgaze, which could occur if small distance recession had been performed at the inferior rectus muscle. An overeffect in relation to inferior oblique recession will only

Functional organization and visual representations in human ventral lateral prefrontal cortex

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Annie Wai Yiu Chan

2013-07-01

Full Text Available Recent neuroimaging studies in both human and non-human primates have identified face selective activation in the ventral lateral prefrontal cortex even in the absence of working memory demands. Further, research has suggested that this face-selective response is largely driven by the presence of the eyes. However, the nature and origin of visual category responses in the ventral lateral prefrontal cortex remain unclear. Further, in a broader sense, how do these findings relate to our current understandings of lateral prefrontal cortex? What do these findings tell us about the underlying function and organization principles of the ventral lateral prefrontal cortex? What is the future direction for investigating visual representations in this cortex? This review focuses on the function, topography, and circuitry of the ventral lateral prefrontal cortex to enhance our understanding of the evolution and development of this cortex.

Focal Stroke in the Developing Rat Motor Cortex Induces Age- and Experience-Dependent Maladaptive Plasticity of Corticospinal System.

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Gennaro, Mariangela; Mattiello, Alessandro; Mazziotti, Raffaele; Antonelli, Camilla; Gherardini, Lisa; Guzzetta, Andrea; Berardi, Nicoletta; Cioni, Giovanni; Pizzorusso, Tommaso

2017-01-01

Motor system development is characterized by an activity-dependent competition between ipsilateral and contralateral corticospinal tracts (CST). Clinical evidence suggests that age is crucial for developmental stroke outcome, with early lesions inducing a "maladaptive" strengthening of ipsilateral projections from the healthy hemisphere and worse motor impairment. Here, we investigated in developing rats the relation between lesion timing, motor outcome and CST remodeling pattern. We induced a focal ischemia into forelimb motor cortex (fM1) at two distinct pre-weaning ages: P14 and P21. We compared long-term motor outcome with changes in axonal sprouting of contralesional CST at red nucleus and spinal cord level using anterograde tracing. We found that P14 stroke caused a more severe long-term motor impairment than at P21, and induced a strong and aberrant contralesional CST sprouting onto denervated spinal cord and red nucleus. The mistargeted sprouting of CST, and the worse motor outcome of the P14 stroke rats were reversed by an early skilled motor training, underscoring the potential of early activity-dependent plasticity in modulating lesion outcome. Thus, changes in the mechanisms controlling CST plasticity occurring during the third postnatal week are associated with age-dependent regulation of the motor outcome after stroke.

Monocular Visual Deprivation Suppresses Excitability in Adult Human Visual Cortex

DEFF Research Database (Denmark)

Lou, Astrid Rosenstand; Madsen, Kristoffer Hougaard; Paulson, Olaf Bjarne

2011-01-01

The adult visual cortex maintains a substantial potential for plasticity in response to a change in visual input. For instance, transcranial magnetic stimulation (TMS) studies have shown that binocular deprivation (BD) increases the cortical excitability for inducing phosphenes with TMS. Here, we...... of visual deprivation has a substantial impact on experience-dependent plasticity of the human visual cortex.......The adult visual cortex maintains a substantial potential for plasticity in response to a change in visual input. For instance, transcranial magnetic stimulation (TMS) studies have shown that binocular deprivation (BD) increases the cortical excitability for inducing phosphenes with TMS. Here, we...... employed TMS to trace plastic changes in adult visual cortex before, during, and after 48 h of monocular deprivation (MD) of the right dominant eye. In healthy adult volunteers, MD-induced changes in visual cortex excitability were probed with paired-pulse TMS applied to the left and right occipital cortex...

Left prefrontal neuronavigated electrode localization in tDCS : 10–20 EEG system versus MRI-guided neuronavigation

NARCIS (Netherlands)

De Witte, Sara; Klooster, Debby; Dedoncker, Josefien; Duprat, Romain; Remue, Jonathan; Baeken, Chris

2018-01-01

Transcranial direct current stimulation (tDCS) involves positioning two electrodes at specifically targeted locations on the human scalp. In neuropsychiatric research, the anode is often placed over the left dorsolateral prefrontal cortex (DLPFC), while the cathode is positioned over a contralateral

Area 5 influences excitability within the primary motor cortex in humans.

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Azra Premji

Full Text Available In non-human primates, Brodmann's area 5 (BA 5 has direct connectivity with primary motor cortex (M1, is largely dedicated to the representation of the hand and may have evolved with the ability to perform skilled hand movement. Less is known about human BA 5 and its interaction with M1 neural circuits related to hand control. The present study examines the influence of BA 5 on excitatory and inhibitory neural circuitry within M1 bilaterally before and after continuous (cTBS, intermittent (iTBS, and sham theta-burst stimulation (sham TBS over left hemisphere BA 5. Using single and paired-pulse TMS, measurements of motor evoked potentials (MEPs, short interval intracortical inhibition (SICI, and intracortical facilitation (ICF were quantified for the representation of the first dorsal interosseous muscle. Results indicate that cTBS over BA 5 influences M1 excitability such that MEP amplitudes are increased bilaterally for up to one hour. ITBS over BA 5 results in an increase in MEP amplitude contralateral to stimulation with a delayed onset that persists up to one hour. SICI and ICF were unaltered following TBS over BA 5. Similarly, F-wave amplitude and latency were unaltered following cTBS over BA 5. The data suggest that BA 5 alters M1 output directed to the hand by influencing corticospinal neurons and not interneurons that mediate SICI or ICF circuitry. Targeting BA 5 via cTBS and iTBS is a novel mechanism to powerfully modulate activity within M1 and may provide an avenue for investigating hand control in healthy populations and modifying impaired hand function in clinical populations.

Characterizing synaptic protein development in human visual cortex enables alignment of synaptic age with rat visual cortex

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Pinto, Joshua G. A.; Jones, David G.; Williams, C. Kate; Murphy, Kathryn M.

2015-01-01

Although many potential neuroplasticity based therapies have been developed in the lab, few have translated into established clinical treatments for human neurologic or neuropsychiatric diseases. Animal models, especially of the visual system, have shaped our understanding of neuroplasticity by characterizing the mechanisms that promote neural changes and defining timing of the sensitive period. The lack of knowledge about development of synaptic plasticity mechanisms in human cortex, and about alignment of synaptic age between animals and humans, has limited translation of neuroplasticity therapies. In this study, we quantified expression of a set of highly conserved pre- and post-synaptic proteins (Synapsin, Synaptophysin, PSD-95, Gephyrin) and found that synaptic development in human primary visual cortex (V1) continues into late childhood. Indeed, this is many years longer than suggested by neuroanatomical studies and points to a prolonged sensitive period for plasticity in human sensory cortex. In addition, during childhood we found waves of inter-individual variability that are different for the four proteins and include a stage during early development (visual cortex and identified a simple linear equation that provides robust alignment of synaptic age between humans and rats. Alignment of synaptic ages is important for age-appropriate targeting and effective translation of neuroplasticity therapies from the lab to the clinic. PMID:25729353

Effects of training programs based on ipsilateral voluntary and stimulated contractions on muscle strength and monopedal postural control of the contralateral limb.

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Kadri, Mohamed Abdelhafid; Noé, Frederic; Nouar, Merbouha Boulahbel; Paillard, Thierry

2017-09-01

To compare the effects of unilateral strength training by stimulated and voluntary contractions on muscle strength and monopedal postural control of the contralateral limb. 36 non-active healthy male subjects were recruited and split randomly into three groups. Two groups of 12 subjects took part in a strength-training program (3 sessions a week over 8 weeks) comprising 43 contractions of the quadriceps femoris of the ipsilateral limb (at 20% of the MVC). One group carried out voluntary contractions exclusively (VOL group), while the other group benefited exclusively from electro-induced contractions (NMES group). The other 12 subjects formed the control (CON) group. Assessments of MVC and monopedal postural control in static and dynamic postural tasks were performed with the ipsilateral (ISPI) and contralateral (CONTRA) limbs before (PRE) and after (POST) completion of the training program. After the training program, the MVC of the IPSI and CONTRA limbs increased similarly for both experimental groups (VOL and NMES). There were no significant improvements of monopedal postural control for the IPSI or CONTRA limbs in either the VOL or NMES experimental group. No change was observed for the CON group over the protocol period. The purposed training program with NMES vs VOL contractions induced strength gains but did not permit any improvement of contralateral monopedal postural control in healthy young subjects. This has potential for therapeutic application and allows clinicians to focus their training programs on dynamic and poly-articular exercises to improve the postural control in young subjects.

Abnormal Functional Connectivity of Anterior Cingulate Cortex in Patients With Primary Insomnia: A Resting-State Functional Magnetic Resonance Imaging Study

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Chao-Qun Yan

2018-06-01

Full Text Available Background: Recently, there have been many reports about abnormalities regarding structural and functional brain connectivity of the patients with primary insomnia. However, the alterations in functional interaction between the left and right cerebral hemispheres have not been well understood. The resting-state fMRI approach, which reveals spontaneous neural fluctuations in blood-oxygen-level-dependent signals, offers a method to quantify functional interactions between the hemispheres directly.Methods: We compared interhemispheric functional connectivity (FC between 26 patients with primary insomnia (48.85 ± 12.02 years and 28 healthy controls (49.07 ± 11.81 years using a voxel-mirrored homotopic connectivity (VMHC method. The patients with primary insomnia and healthy controls were matched for age, gender, and education. Brain regions, which had significant differences in VMHC maps between the primary insomnia and healthy control groups, were defined as seed region of interests. A seed-based approach was further used to reveal significant differences of FC between the seeds and the whole contralateral hemisphere.Results: The patients with primary insomnia showed higher VMHC than healthy controls in the anterior cingulate cortex (ACC bilaterally. The seed-based analyses demonstrated increased FC between the left ACC and right thalamus (and the right ACC and left orbitofrontal cortex in patients with primary insomnia, revealing abnormal connectivity between the two cerebral hemispheres. The VMHC values in the ACC were positively correlated with the time to fall asleep and Self-Rating Depression Scale scores (SDS.Conclusions: The results demonstrate that there is abnormal interhemispheric resting-state FC in the brain regions of patients with primary insomnia, especially in the ACC. Our finding demonstrates valid evidence that the ACC is an area of interest in the neurobiology of primary insomnia.

The medial prefrontal cortex-lateral entorhinal cortex circuit is essential for episodic-like memory and associative object-recognition.

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Chao, Owen Y; Huston, Joseph P; Li, Jay-Shake; Wang, An-Li; de Souza Silva, Maria A

2016-05-01

The prefrontal cortex directly projects to the lateral entorhinal cortex (LEC), an important substrate for engaging item-associated information and relaying the information to the hippocampus. Here we ask to what extent the communication between the prefrontal cortex and LEC is critically involved in the processing of episodic-like memory. We applied a disconnection procedure to test whether the interaction between the medial prefrontal cortex (mPFC) and LEC is essential for the expression of recognition memory. It was found that male rats that received unilateral NMDA lesions of the mPFC and LEC in the same hemisphere, exhibited intact episodic-like (what-where-when) and object-recognition memories. When these lesions were placed in the opposite hemispheres (disconnection), episodic-like and associative memories for object identity, location and context were impaired. However, the disconnection did not impair the components of episodic memory, namely memory for novel object (what), object place (where) and temporal order (when), per se. Thus, the present findings suggest that the mPFC and LEC are a critical part of a neural circuit that underlies episodic-like and associative object-recognition memory. © 2015 Wiley Periodicals, Inc.

Unilateral hearing during development: hemispheric specificity in plastic reorganizations

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Andrej eKral

2013-11-01

Full Text Available The present study investigates the hemispheric contributions of neuronal reorganization following early single-sided hearing (unilateral deafness. The experiments were performed on ten cats from our colony of deaf white cats. Two were identified in early hearing screening as unilaterally congenitally deaf. The remaining eight were bilaterally congenitally deaf, unilaterally implanted at different ages with a cochlear implant. Implanted animals were chronically stimulated using a single-channel portable signal processor for two to five months. Microelectrode recordings were performed at the primary auditory cortex under stimulation at the hearing and deaf ear with bilateral cochlear implants. Local field potentials (LFPs were compared at the cortex ipsilateral and contralateral to the hearing ear. The focus of the study was on the morphology and the onset latency of the LFPs. The data revealed that effects of hearing experience were more pronounced when stimulating the hearing ear. With respect to morphology of LFPs, pronounced hemisphere-specific effects were observed. Morphology of amplitude-normalized LFPs for stimulation of the deaf and the hearing ear was similar for responses recorded at the same hemisphere. However, when comparisons were performed between the hemispheres, the morphology was more dissimilar even though the same ear was stimulated. This demonstrates hemispheric specificity of some cortical adaptations irrespective of the ear stimulated. The results suggest a specific adaptation process at the hemisphere ipsilateral to the hearing ear, involving specific (down-regulated inhibitory mechanisms not found in the contralateral hemisphere. Finally, onset latencies revealed that the sensitive period for the cortex ipsilateral to the hearing ear is shorter than that for the contralateral cortex. Unilateral hearing experience leads to a functionally-asymmetric brain with different neuronal reorganizations and different sensitive

Bilateral contributions of the cerebellum to the complex motor tasks on EPI fMRI

International Nuclear Information System (INIS)

Chung, Eun Chul; Youn, Eun Kyung; Lee, Young Rae; Kim, Yoo Kyung; Park, Kee Duk

1999-01-01

To demonstrate activation signals within the cerebellar cortex and to determine the side of the cerebellar cortex eliciting activation signals in response to complex motor tasks, as seen on EPI fMRI. Seven right-handed subjects (M : F=3 : 4; mean age, 30.3 years) underwent repetitive finger apposition with the dominant right hand. Using a 1.5 T MRI scanner, EPI fMR images were obtained. MR parameters used for EPI fMRI were TR/TE/Flip angle : 0.96 msec/64msec/90 deg FOV 22cm, 128 X 128 matrix, 10 slices, 10mm thickness while those for SE T1 weighted localized images were TR/TE : 450/16, FOV 23cm, 256 X 256 matrix. The paradigm was three sets of alternate resting and moving fingers for six cycles, resulting in times of 360 seconds (10 slices X 15 EPI X 6 cycles = 900 images). Image processing involved the use of a 200mHz Dual Pentium PC with homemade software. T-testing (p < 0.005 approx.= p < 0.0005) and time series analysis were performed, and to verify the locations of activated regions, resulting images were analyzed in a color-coded overlay to reference T1-weighted spin echo coronal images. Percentage change in signal intensity (PCSI) was calculated from the processed data. All normal subjects showed significant activation signals in both the contralateral (left) primary motor cortex (PCSI = 3.12% 0.96) and ipsilateral (right) cerebellar cortex (PCSI = 3.09% ±1.14). Signal activation was detected in the contralateral supplemental motor area (2.91% ±0.82), and motor activation in the anterior upper half of the contralateral cerebellum (PCSI 2.50% ±0.69). The difference in activation signals between both sides of the cerebellar cortex was not statistically significant. All data were matched with time-series analysis. Bilateral cerebellar activation is associated with unilateral complex finger movements, as seen on fMRI. This result may support the recent neurological observation that the cerebellum may exert bilateral effects on motor performance

Carotid endarterectomy in patients with occlusion of the contralateral carotid artery. Perioperative risk and late results

DEFF Research Database (Denmark)

Sillesen, H; Schroeder, T; Rasmussen, L

1987-01-01

severe strokes when compared to patients with only minor reduction in CPP. In addition, the internal carotid artery blood flow following endarterectomy was significantly higher in the low pressure group (P less than 0.02). No patients were lost during follow-up, for a mean of 34 months. The cumulative....... Compared with a complication rate of about 5% previously reported from this institution, this clearly indicates contralateral carotid occlusion as a major risk factor in carotid surgery. Though not statistically significant, patients with severely reduced cerebral perfusion pressure (CPP) had suffered more...

Self-Reported Usage, Functional Benefit, and Audiologic Characteristics of Cochlear Implant Patients Who Use a Contralateral Hearing Aid

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Arlene C. Neuman

2017-03-01

Full Text Available Ninety-four unilateral CI patients with bimodal listening experience (CI plus HA in contralateral ear completed a questionnaire that focused on attitudes toward hearing aid use postimplantation, patterns of usage, and perceived bimodal benefits in daily life. Eighty participants continued HA use and 14 discontinued HA use at the time of the questionnaire. Participant responses provided useful information for counseling patients both before and after implantation. The majority of continuing bimodal (CI plus HA participants reported adapting to using both devices within 3 months and also reported that they heard better bimodally in quiet, noisy, and reverberant conditions. They also perceived benefits including improved sound quality, better music enjoyment, and sometimes a perceived sense of acoustic balance. Those who discontinued HA use found either that using the HA did not provide additional benefit over the CI alone or that using the HA degraded the signal from the CI. Because there was considerable overlap in the audiograms and in speech recognition performance in the unimplanted ear between the two groups, we recommend that unilateral CI recipients are counseled to continue to use the HA in the contralateral ear postimplantation in order to determine whether or not they receive functional or perceived benefit from using both devices together.

Sparing of contralateral major salivary glands has a significant effect on oral health in patients treated with radical radiotherapy of head and neck tumors

International Nuclear Information System (INIS)

Beer, K.T.; Greiner, R.H.; Zehnder, D.; Lussi, A.

2002-01-01

Background: Has a conscious exclusion of the contralateral major salivary glands (parotid, submandibular, and sublingual glands) a significant impact on the milieu of the oral cavity (saliva flow, pH, buffer capacity, and colonisation with Streptococcus mutans) in patients with ENT tumors receiving radical radiotherapy? Patients and Methods: 20 consecutive consentient patients with ENT tumors were evaluated once before, weekly during, and 6 weeks after the end of treatment in regard to saliva flow, pH, buffer capacity, and colonisation with Streptococcus mutans. In 13 patients the major salivary glands on both sides were included in the treated volume, in seven patients the treatment portals excluded consciously the contralateral major salivary glands. Results: The stimulated saliva flow decreases already during the 1st week of radiotherapy, the decrease follows the dose exponentially; the saliva flow is further reduced in the weeks after the end of treatment. The effect is less pronounced in patients with sparing of contralateral major salivary glands. The majority of patients with unilateral sparing of the major salivary glands retain the baseline value of buffer capacity, whereas buffer capacity of all patients with inclusion of all major salivary glands is markedly reduced with 20 Gy already, without signs of recovery when treatment has stopped. With unilateral salivary gland sparing the pH always remains basic, in bilaterally irradiated patients the pH changes from a mean of 7.3 to 5.8 during treatment. The colonisation with Streptococcus mutans varies little in both groups during the radiotherapy; after the end of therapy, it is higher in bilaterally irradiated patients. Conclusions: The conscious arrangement of irradiation portals in order to spare contralateral major salivary glands in patients with radical radiotherapy of ENT tumors has a significant influence on the oral environment: the stimulated saliva flow is higher, the buffer capacity retains the

Physical therapy in the conservative treatment for anterior cruciate ligament rupture followed by contralateral rupture: case report

OpenAIRE

Almeida, Gabriel Peixoto Leão; Arruda, Gilvan de Oliveira; Marques, Amélia Pasqual

2014-01-01

Although the surgical reconstruction be the obvious indication for the anterior cruciate ligament (ACL) lesion, there is no consensus on whether the results of surgery are superior to those obtained with nonsurgical management. The objective of this report was to describe a case of nonsurgical treatment for ACL rupture followed by a contralateral rupture. A 28-year-old female practitioner of muay-thai and handball suffered a non-contact ACL rupture in the left knee, and three months after the...

The Contralateral Connections of Optical Pathway in Chick Brain%鸡脑光信息通路的对侧联系

Institute of Scientific and Technical Information of China (English)

刘春凌; 胡满; 王鹏; 张利卫; 杨昊; 刘振斌

2012-01-01

　　Purpose:In order to further understand the nerve regulation mechanism in affect of light on chick pro-duction performance so as to provide some theoretical basis for the application on the using of light to improve the chick production performance and on the veterinary nerve surgery, the contralateral connections of optical pathway in chick brain were observed using HRP tracing method. Methods: Small amount of 3% WGA-HRP was injected into Rt in chicken brain using the stereotaxic instrument. After survival period of 30 hours, the chicks were per-fused to fix the animals. The brains were removed and were sectioned by the cryostat. The HRP labeled nervous cells projecting to contralateral side in the optical pathway were tested using TMB method. Results: After injecting WGA-HRP into nucleus rotundus, besides the numerous labled nervous cells in the ipsilateral SGC and SP/IPS of the chicken tectofugal optical pathway, some HRP labeled nervous cells and fibers were also observed in the con-tralateral SGC, SP/IPS and nucleus rotundus. Their number is fewer than those of the ipsilateral side, having smaller distributing area. The locations of the labeled nervous cells and fibers are different with the regions of the contralateral nucleus rotundus. Their labeled extent showed a spindlye shape from the anterior to the posterior part of the nucleus rotundus. Discussion: The results indicated that the ipsilateral projection is the main projection in the tectofugal optical pathway. There are also some contralateral projections in it. The contralateral projections may play a role by assistant and inhibition process. The projection could make the specific units combined and man-aged the messages came from binoculus, being helpful for the cerebrum to gain more exact and overall messages.%　　目的：为了进一步阐明光照对鸡生产性能的神经调节机制,为养鸡生产科学利用光照和兽医神经外科学提供一定的理论依据,用 HRP �

Single-session tDCS over the dominant hemisphere affects contralateral spectral EEG power, but does not enhance neurofeedback-guided event-related desynchronization of the non-dominant hemisphere's sensorimotor rhythm.

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Mondini, Valeria; Mangia, Anna Lisa; Cappello, Angelo

2018-01-01

Transcranial direct current stimulation (tDCS) and neurofeedback-guided motor imagery (MI) have attracted considerable interest in neurorehabilitation, given their ability to influence neuroplasticity. As tDCS has been shown to modulate event-related desynchronization (ERD), the neural signature of motor imagery detected for neurofeedback, a combination of the techniques was recently proposed. One limitation of this approach is that the area targeted for stimulation is the same from which the signal for neurofeedback is acquired. As tDCS may interfere with proximal electroencephalographic (EEG) electrodes, in this study our aim was to test whether contralateral tDCS could have interhemispheric effects on the spectral power of the unstimulated hemisphere, possibly mediated by transcallosal connection, and whether such effects could be used to enhance ERD magnitudes. A contralateral stimulation approach would indeed facilitate co-registration, as the stimulation electrode would be far from the recording sites. Twenty right-handed healthy volunteers (aged 21 to 32) participated in the study: ten assigned to cathodal, ten to anodal versus sham stimulation. We applied stimulation over the dominant (left) hemisphere, and assessed ERD and spectral power over the non-dominant (right) hemisphere. The effect of tDCS was evaluated over time. Spectral power was assessed in theta, alpha and beta bands, under both rest and MI conditions, while ERD was evaluated in alpha and beta bands. Two main findings emerged: (1) contralateral alpha-ERD was reduced after anodal (p = 0.0147), but not enhanced after cathodal tDCS; (2) both stimulations had remote effects on the spectral power of the contralateral hemisphere, particularly in theta and alpha (significant differences in the topographical t-value maps). The absence of contralateral cathodal ERD enhancement suggests that the protocol is not applicable in the context of MI training. Nevertheless, ERD results of anodal and spectral

Activity in the primary somatosensory cortex induced by reflexological stimulation is unaffected by pseudo-information: a functional magnetic resonance imaging study.

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Miura, Naoki; Akitsuki, Yuko; Sekiguchi, Atsushi; Kawashima, Ryuta

2013-05-27

Reflexology is an alternative medical practice that produces beneficial effects by applying pressure to specific reflex areas. Our previous study suggested that reflexological stimulation induced cortical activation in somatosensory cortex corresponding to the stimulated reflex area; however, we could not rule out the possibility of a placebo effect resulting from instructions given during the experimental task. We used functional magnetic resonance imaging (fMRI) to investigate how reflexological stimulation of the reflex area is processed in the primary somatosensory cortex when correct and pseudo-information about the reflex area is provided. Furthermore, the laterality of activation to the reflexological stimulation was investigated. Thirty-two healthy Japanese volunteers participated. The experiment followed a double-blind design. Half of the subjects received correct information, that the base of the second toe was the eye reflex area, and pseudo-information, that the base of the third toe was the shoulder reflex area. The other half of the subjects received the opposite information. fMRI time series data were acquired during reflexological stimulation to both feet. The experimenter stimulated each reflex area in accordance with an auditory cue. The fMRI data were analyzed using a conventional two-stage approach. The hemodynamic responses produced by the stimulation of each reflex area were assessed using a general linear model on an intra-subject basis, and a two-way repeated-measures analysis of variance was performed on an intersubject basis to determine the effect of reflex area laterality and information accuracy. Our results indicated that stimulation of the eye reflex area in either foot induced activity in the left middle postcentral gyrus, the area to which tactile sensation to the face projects, as well as in the postcentral gyrus contralateral foot representation area. This activity was not affected by pseudo information. The results also indicate

Activity in the primary somatosensory cortex induced by reflexological stimulation is unaffected by pseudo-information: a functional magnetic resonance imaging study

Science.gov (United States)

2013-01-01

Background Reflexology is an alternative medical practice that produces beneficial effects by applying pressure to specific reflex areas. Our previous study suggested that reflexological stimulation induced cortical activation in somatosensory cortex corresponding to the stimulated reflex area; however, we could not rule out the possibility of a placebo effect resulting from instructions given during the experimental task. We used functional magnetic resonance imaging (fMRI) to investigate how reflexological stimulation of the reflex area is processed in the primary somatosensory cortex when correct and pseudo-information about the reflex area is provided. Furthermore, the laterality of activation to the reflexological stimulation was investigated. Methods Thirty-two healthy Japanese volunteers participated. The experiment followed a double-blind design. Half of the subjects received correct information, that the base of the second toe was the eye reflex area, and pseudo-information, that the base of the third toe was the shoulder reflex area. The other half of the subjects received the opposite information. fMRI time series data were acquired during reflexological stimulation to both feet. The experimenter stimulated each reflex area in accordance with an auditory cue. The fMRI data were analyzed using a conventional two-stage approach. The hemodynamic responses produced by the stimulation of each reflex area were assessed using a general linear model on an intra-subject basis, and a two-way repeated-measures analysis of variance was performed on an intersubject basis to determine the effect of reflex area laterality and information accuracy. Results Our results indicated that stimulation of the eye reflex area in either foot induced activity in the left middle postcentral gyrus, the area to which tactile sensation to the face projects, as well as in the postcentral gyrus contralateral foot representation area. This activity was not affected by pseudo information

Neural correlates of mirth and laughter: a direct electrical cortical stimulation study.

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Yamao, Yukihiro; Matsumoto, Riki; Kunieda, Takeharu; Shibata, Sumiya; Shimotake, Akihiro; Kikuchi, Takayuki; Satow, Takeshi; Mikuni, Nobuhiro; Fukuyama, Hidenao; Ikeda, Akio; Miyamoto, Susumu

2015-05-01

Laughter consists of both motor and emotional aspects. The emotional component, known as mirth, is usually associated with the motor component, namely, bilateral facial movements. Previous electrical cortical stimulation (ES) studies revealed that mirth was associated with the basal temporal cortex, inferior frontal cortex, and medial frontal cortex. Functional neuroimaging implicated a role for the left inferior frontal and bilateral temporal cortices in humor processing. However, the neural origins and pathways linking mirth with facial movements are still unclear. We hereby report two cases with temporal lobe epilepsy undergoing subdural electrode implantation in whom ES of the left basal temporal cortex elicited both mirth and laughter-related facial muscle movements. In one case with normal hippocampus, high-frequency ES consistently caused contralateral facial movement, followed by bilateral facial movements with mirth. In contrast, in another case with hippocampal sclerosis (HS), ES elicited only mirth at low intensity and short duration, and eventually laughter at higher intensity and longer duration. In both cases, the basal temporal language area (BTLA) was located within or adjacent to the cortex where ES produced mirth. In conclusion, the present direct ES study demonstrated that 1) mirth had a close relationship with language function, 2) intact mesial temporal structures were actively engaged in the beginning of facial movements associated with mirth, and 3) these emotion-related facial movements had contralateral dominance. Copyright © 2014 Elsevier Ltd. All rights reserved.

Intraoperative functional MRI as a new approach to monitor deep brain stimulation in Parkinson's disease

International Nuclear Information System (INIS)

Hesselmann, Volker; Sorger, Bettina; Girnus, Ralf; Lasek, Kathrin; Schulte, Oliver; Krug, Barbara; Lackner, Klaus; Maarouf, Mohammad; Sturm, Volker; Wedekind, Christoph; Bunke, Juergen

2004-01-01

This article deals with technical aspects of intraoperative functional magnetic resonance imaging (fMRI) for monitoring the effect of deep brain stimulation (DBS) in a patient with Parkinson's disease. Under motor activation, therapeutic high-frequency stimulation of the subthalamic nucleus was accompanied by an activation decrease in the contralateral primary sensorimotor cortex and the ipsilateral cerebellum. Furthermore, an activation increase in the contralateral basal ganglia and insula region were detected. These findings demonstrate that fMRI constitutes a promising clinical application for investigating brain activity changes induced by DBS. (orig.)

Magnetoencephalographic study of hand and foot sensorimotor organization in 325 consecutive patients evaluated for tumor or epilepsy surgery

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Ronald B. Willemse

2016-01-01

Conclusions: MEG localization of sensorimotor cortex activation was more successful for the hand compared to the foot. In patients with neural lesions, there were signs of brain reorganization as measured by more frequent ipsilateral motor cortical activation of the foot in addition to the traditional sensory and motor activation patterns in the contralateral hemisphere. The presence of ipsilateral neural reorganization, especially around the foot motor area, suggests that careful mapping of the hand and foot in both contralateral and ipsilateral hemispheres prior to surgery might minimize postoperative deficits.

The Significance of Memory in Sensory Cortex.

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Muckli, Lars; Petro, Lucy S

2017-05-01

Early sensory cortex is typically investigated in response to sensory stimulation, masking the contribution of internal signals. Recently, van Kerkoerle and colleagues reported that attention and memory signals segregate from sensory signals within specific layers of primary visual cortex, providing insight into the role of internal signals in sensory processing. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Non-Invasive Brain Stimulation to Enhance Post-Stroke Recovery.

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Kubis, Nathalie

2016-01-01

Brain plasticity after stroke remains poorly understood. Patients may improve spontaneously within the first 3 months and then more slowly in the coming year. The first day, decreased edema and reperfusion of the ischemic penumbra may possibly account for these phenomena, but the improvement during the next weeks suggests plasticity phenomena and cortical reorganization of the brain ischemic areas and of more remote areas. Indeed, the injured ischemic motor cortex has a reduced cortical excitability at the acute phase and a suspension of the topographic representation of affected muscles, whereas the contralateral motor cortex has an increased excitability and an enlarged somatomotor representation; furthermore, contralateral cortex exerts a transcallosal interhemispheric inhibition on the ischemic cortex. This results from the imbalance of the physiological reciprocal interhemispheric inhibition of each hemisphere on the other, contributing to worsening of neurological deficit. Cortical excitability is measurable through transcranial magnetic stimulation (TMS) and prognosis has been established according to the presence of motor evoked potentials (MEP) at the acute phase of stroke, which is predictive of better recovery. Conversely, the lack of response to early stimulation is associated with a poor functional outcome. Non-invasive stimulation techniques such as repetitive TMS (rTMS) or transcranial direct current stimulation (tDCS) have the potential to modulate brain cortical excitability with long lasting effects. In the setting of cerebrovascular disease, around 1000 stroke subjects have been included in placebo-controlled trials so far, most often with an objective of promoting motor recovery of the upper limb. High frequency repetitive stimulation (>3 Hz) rTMS, aiming to increase excitability of the ischemic cortex, or low frequency repetitive stimulation (≤1 Hz), aiming to reduce excitability of the contralateral homonymous cortex, or combined therapies

Non invasive brain stimulation to enhance post-stroke recovery

Directory of Open Access Journals (Sweden)

Nathalie Kubis

2016-07-01

Full Text Available Brain plasticity after stroke remains poorly understood. Patients may improve spontaneously within the first 3 months and then more slowly in the coming year. The first days, decreased edema and reperfusion of the ischemic penumbra may possibly account for these phenomena, but the improvement during the next weeks suggests plasticity phenomena and cortical reorganization of the brain ischemic areas and of more remote areas. Indeed, the injured ischemic motor cortex has a reduced cortical excitability at the acute phase and a suspension of the topographic representation of affected muscles, whereas the contralateral motor cortex has an increased excitability and an enlarged somatomotor representation; furthermore, contralateral cortex exerts a transcallosal interhemispheric inhibition on the ischemic cortex. This results from the imbalance of the physiological reciprocal interhemispheric inhibition of each hemisphere on the other, contributing to worsening of neurological deficit. Cortical excitability is measurable through transcranial magnetic stimulation (TMS and prognosis has been established according to the presence of motor evoked potentials (MEP at the acute phase of stroke, which is predictive of better recovery. Conversely, the lack of response to early stimulation is associated with a poor functional outcome. Non-invasive stimulation techniques such as repetitive TMS (rTMS or transcranial direct current stimulation (tDCS have the potential to modulate brain cortical excitability with long lasting effects. In the setting of cerebrovascular disease, around 1000 stroke subjects have been included in placebo-controlled trials so far, most often with an objective of promoting motor recovery of the upper limb. High frequency repetitive stimulation (> 3 Hz rTMS, aiming to increase excitability of the ischemic cortex, or low frequency repetitive stimulation (≤ 1 Hz, aiming to reduce excitability of the contralateral homonymous cortex, or

Short-term retention of visual information: Evidence in support of feature-based attention as an underlying mechanism.

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Sneve, Markus H; Sreenivasan, Kartik K; Alnæs, Dag; Endestad, Tor; Magnussen, Svein

2015-01-01

Retention of features in visual short-term memory (VSTM) involves maintenance of sensory traces in early visual cortex. However, the mechanism through which this is accomplished is not known. Here, we formulate specific hypotheses derived from studies on feature-based attention to test the prediction that visual cortex is recruited by attentional mechanisms during VSTM of low-level features. Functional magnetic resonance imaging (fMRI) of human visual areas revealed that neural populations coding for task-irrelevant feature information are suppressed during maintenance of detailed spatial frequency memory representations. The narrow spectral extent of this suppression agrees well with known effects of feature-based attention. Additionally, analyses of effective connectivity during maintenance between retinotopic areas in visual cortex show that the observed highlighting of task-relevant parts of the feature spectrum originates in V4, a visual area strongly connected with higher-level control regions and known to convey top-down influence to earlier visual areas during attentional tasks. In line with this property of V4 during attentional operations, we demonstrate that modulations of earlier visual areas during memory maintenance have behavioral consequences, and that these modulations are a result of influences from V4. Copyright © 2014 Elsevier Ltd. All rights reserved.

Olfactocentric paralimbic cortex morphology in adolescents with bipolar disorder

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Wang, Fei; Kalmar, Jessica H.; Womer, Fay Y.; Edmiston, Erin E.; Chepenik, Lara G.; Chen, Rachel; Spencer, Linda; Blumberg, Hilary P.

2011-01-01

The olfactocentric paralimbic cortex plays a critical role in the regulation of emotional and neurovegetative functions that are disrupted in core features of bipolar disorder. Adolescence is thought to be a critical period in both the maturation of the olfactocentric paralimbic cortex and in the emergence of bipolar disorder pathology. Together, these factors implicate a central role for the olfactocentric paralimbic cortex in the development of bipolar disorder and suggest that abnormalitie...

Brain imaging during seizure: ictal brain SPECT

International Nuclear Information System (INIS)

Kottamasu, Sambasiva Rao

1997-01-01

The role of single photon computed tomography (SPECT) in presurgical localization of medically intractable complex partial epilepsy (CPE) in children is reviewed. 99m Technetium neurolite, a newer lipophylic agent with a high first pass brain extraction and little or no redistribution is injected during a seizure, while the child is monitored with a video recording and continuous EEG and SPECT imaging is performed in the next 1-3 hours with the images representing regional cerebral profusion at the time of injection. On SPECT studies performed with radiopharmaceutical injected during a seizure, ictal focus is generally hypervascular. Other findings on ictal brain SPECT include hypoperfusion of adjacent cerebral cortex and white matter, hyperperfusion of contralateral motor cortex, hyperperfusion of ipsilateral basal ganglia and thalamus, brain stem and contralateral cerebellum. Ictal brain SPECT is non-invasive, cost effective and highly sensitive for localization of epileptic focus in patients with intractable CPE. (author)

Contextual modulation of primary visual cortex by auditory signals.

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Petro, L S; Paton, A T; Muckli, L

2017-02-19

Early visual cortex receives non-feedforward input from lateral and top-down connections (Muckli & Petro 2013 Curr. Opin. Neurobiol. 23, 195-201. (doi:10.1016/j.conb.2013.01.020)), including long-range projections from auditory areas. Early visual cortex can code for high-level auditory information, with neural patterns representing natural sound stimulation (Vetter et al. 2014 Curr. Biol. 24, 1256-1262. (doi:10.1016/j.cub.2014.04.020)). We discuss a number of questions arising from these findings. What is the adaptive function of bimodal representations in visual cortex? What type of information projects from auditory to visual cortex? What are the anatomical constraints of auditory information in V1, for example, periphery versus fovea, superficial versus deep cortical layers? Is there a putative neural mechanism we can infer from human neuroimaging data and recent theoretical accounts of cortex? We also present data showing we can read out high-level auditory information from the activation patterns of early visual cortex even when visual cortex receives simple visual stimulation, suggesting independent channels for visual and auditory signals in V1. We speculate which cellular mechanisms allow V1 to be contextually modulated by auditory input to facilitate perception, cognition and behaviour. Beyond cortical feedback that facilitates perception, we argue that there is also feedback serving counterfactual processing during imagery, dreaming and mind wandering, which is not relevant for immediate perception but for behaviour and cognition over a longer time frame.This article is part of the themed issue 'Auditory and visual scene analysis'. © 2017 The Authors.

Higher-order Brain Areas Associated with Real-time Functional MRI Neurofeedback Training of the Somato-motor Cortex.

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Auer, Tibor; Dewiputri, Wan Ilma; Frahm, Jens; Schweizer, Renate

2018-05-15

Neurofeedback (NFB) allows subjects to learn self-regulation of neuronal brain activation based on information about the ongoing activation. The implementation of real-time functional magnetic resonance imaging (rt-fMRI) for NFB training now facilitates the investigation into underlying processes. Our study involved 16 control and 16 training right-handed subjects, the latter performing an extensive rt-fMRI NFB training using motor imagery. A previous analysis focused on the targeted primary somato-motor cortex (SMC). The present study extends the analysis to the supplementary motor area (SMA), the next higher brain area within the hierarchy of the motor system. We also examined transfer-related functional connectivity using a whole-volume psycho-physiological interaction (PPI) analysis to reveal brain areas associated with learning. The ROI analysis of the pre- and post-training fMRI data for motor imagery without NFB (transfer) resulted in a significant training-specific increase in the SMA. It could also be shown that the contralateral SMA exhibited a larger increase than the ipsilateral SMA in the training and the transfer runs, and that the right-hand training elicited a larger increase in the transfer runs than the left-hand training. The PPI analysis revealed a training-specific increase in transfer-related functional connectivity between the left SMA and frontal areas as well as the anterior midcingulate cortex (aMCC) for right- and left-hand trainings. Moreover, the transfer success was related with training-specific increase in functional connectivity between the left SMA and the target area SMC. Our study demonstrates that NFB training increases functional connectivity with non-targeted brain areas. These are associated with the training strategy (i.e., SMA) as well as with learning the NFB skill (i.e., aMCC and frontal areas). This detailed description of both the system to be trained and the areas involved in learning can provide valuable information

Remapping high-capacity, pre-Attentive, fragile sensory memory

NARCIS (Netherlands)

Zerr, Paul; Gayet, Surya; Mulder, Kees; Pinto, Yaïr; Sligte, Ilja; Van Der Stigchel, Stefan

2017-01-01

Humans typically make several saccades per second. This provides a challenge for the visual system as locations are largely coded in retinotopic (eye-centered) coordinates. Spatial remapping, the updating of retinotopic location coordinates of items in visuospatial memory, is typically assumed to be

Remapping high-capacity, pre-attentive, fragile sensory memory

NARCIS (Netherlands)

Zerr, P.; Gayet, S.; Mulder, K.T.; Pinto, Y.; Sligte, I.G.; Stigchel, S. van der

2017-01-01

Humans typically make several saccades per second. This provides a challenge for the visual system as locations are largely coded in retinotopic (eye-centered) coordinates. Spatial remapping, the updating of retinotopic location coordinates of items in visuospatial memory, is typically assumed to be

Role of the ventrolateral orbital cortex and medial prefrontal cortex in incentive downshift situations.

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Ortega, Leonardo A; Glueck, Amanda C; Uhelski, Megan; Fuchs, Perry N; Papini, Mauricio R

2013-05-01

The present research evaluated the role of two prefrontal cortex areas, the ventrolateral orbital cortex (VLO) and the medial prefrontal cortex (mPFC), on two situations involving incentive downshifts, consummatory successive negative contrast (cSNC) with sucrose solutions and Pavlovian autoshaping following continuous vs. partial reinforcement with food pellets. Animals received electrolytic lesions and then were tested on cSNC, autoshaping, open-field activity, and sucrose sensitivity. Lesions of the VLO reduced suppression of consummatory behavior after the incentive downshift, but only during the first downshift trial, and also eliminated the enhancement of anticipatory behavior during partial reinforcement, relative to continuous reinforcement, in autoshaping. There was no evidence of specific effects of mPFC lesions on incentive downshifts. Open-field activity was also reduced by VLO lesions, but only in the central area, whereas mPFC lesions had no observable effects on activity. Animals with mPFC lesions exhibited decreased consumption of the lowest sucrose concentration, whereas no effects were observed in animals with VLO lesions. These results suggest that the VLO may exert nonassociative (i.e., motivational, emotional) influences on behavior in situations involving incentive downshifts. No clear role on incentive downshift was revealed by mPFC lesions. Copyright © 2013 Elsevier B.V. All rights reserved.

A non-invasive, quantitative study of broadband spectral responses in human visual cortex.

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Eline R Kupers

Full Text Available Currently, non-invasive methods for studying the human brain do not routinely and reliably measure spike-rate-dependent signals, independent of responses such as hemodynamic coupling (fMRI and subthreshold neuronal synchrony (oscillations and event-related potentials. In contrast, invasive methods-microelectrode recordings and electrocorticography (ECoG-have recently measured broadband power elevation in field potentials (~50-200 Hz as a proxy for locally averaged spike rates. Here, we sought to detect and quantify stimulus-related broadband responses using magnetoencephalography (MEG. Extracranial measurements like MEG and EEG have multiple global noise sources and relatively low signal-to-noise ratios; moreover high frequency artifacts from eye movements can be confounded with stimulus design and mistaken for signals originating from brain activity. For these reasons, we developed an automated denoising technique that helps reveal the broadband signal of interest. Subjects viewed 12-Hz contrast-reversing patterns in the left, right, or bilateral visual field. Sensor time series were separated into evoked (12-Hz amplitude and broadband components (60-150 Hz. In all subjects, denoised broadband responses were reliably measured in sensors over occipital cortex, even in trials without microsaccades. The broadband pattern was stimulus-dependent, with greater power contralateral to the stimulus. Because we obtain reliable broadband estimates with short experiments (~20 minutes, and with sufficient signal-to-noise to distinguish responses to different stimuli, we conclude that MEG broadband signals, denoised with our method, offer a practical, non-invasive means for characterizing spike-rate-dependent neural activity for addressing scientific questions about human brain function.

Interpretation of the function of the striate cortex

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Garner, Bernardette M.; Paplinski, Andrew P.

2000-04-01

Biological neural networks do not require retraining every time objects move in the visual field. Conventional computer neural networks do not share this shift-invariance. The brain compensates for movements in the head, body, eyes and objects by allowing the sensory data to be tracked across the visual field. The neurons in the striate cortex respond to objects moving across the field of vision as is seen in many experiments. It is proposed, that the neurons in the striate cortex allow continuous angle changes needed to compensate for changes in orientation of the head, eyes and the motion of objects in the field of vision. It is hypothesized that the neurons in the striate cortex form a system that allows for the translation, some rotation and scaling of objects and provides a continuity of objects as they move relative to other objects. The neurons in the striate cortex respond to features which are fundamental to sight, such as orientation of lines, direction of motion, color and contrast. The neurons that respond to these features are arranged on the cortex in a way that depends on the features they are responding to and on the area of the retina from which they receive their inputs.

Portal vein ligation is as effective as sequential portal vein and hepatic artery ligation in inducing contralateral liver hypertrophy in a rat model

NARCIS (Netherlands)

Veteläinen, Reeta; Dinant, Sander; van Vliet, Arlène; van Gulik, Thomas M.

2006-01-01

PURPOSE: Dual embolization of the hepatic artery and portal vein (PV) has been proposed to enhance contralateral liver regeneration before resection. The aim of this study was to evaluate the effect of PV ligation compared with simultaneous or sequential dual ligation on regeneration,

The primary motor and premotor areas of the human cerebral cortex.

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Chouinard, Philippe A; Paus, Tomás

2006-04-01

Brodmann's cytoarchitectonic map of the human cortex designates area 4 as cortex in the anterior bank of the precentral sulcus and area 6 as cortex encompassing the precentral gyrus and the posterior portion of the superior frontal gyrus on both the lateral and medial surfaces of the brain. More than 70 years ago, Fulton proposed a functional distinction between these two areas, coining the terms primary motor area for cortex in Brodmann area 4 and premotor area for cortex in Brodmann area 6. The parcellation of the cortical motor system has subsequently become more complex. Several nonprimary motor areas have been identified in the brain of the macaque monkey, and associations between anatomy and function in the human brain are being tested continuously using brain mapping techniques. In the present review, the authors discuss the unique properties of the primary motor area (M1), the dorsal portion of the premotor cortex (PMd), and the ventral portion of the premotor cortex (PMv). They end this review by discussing how the premotor areas influence M1.

Collateral Projections Innervate the Mammillary Bodies and Retrosplenial Cortex: A New Category of Hippocampal Cells

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O’Mara, Shane M.

2018-01-01

To understand the hippocampus, it is necessary to understand the subiculum. Unlike other hippocampal subfields, the subiculum projects to almost all distal hippocampal targets, highlighting its critical importance for external networks. The present studies, in male rats and mice, reveal a new category of dorsal subiculum neurons that innervate both the mammillary bodies (MBs) and the retrosplenial cortex (RSP). These bifurcating neurons comprise almost half of the hippocampal cells that project to RSP. The termination of these numerous collateral projections was visualized within the medial mammillary nucleus and the granular RSP (area 29). These collateral projections included subiculum efferents that cross to the contralateral MBs. Within the granular RSP, the collateral projections form a particularly dense plexus in deep Layer II and Layer III. This retrosplenial termination site colocalized with markers for VGluT2 and neurotensin. While efferents from the hippocampal CA fields standardly collateralize, subiculum projections often have only one target site. Consequently, the many collateral projections involving the RSP and the MBs present a relatively unusual pattern for the subiculum, which presumably relates to how both targets have complementary roles in spatial processing. Furthermore, along with the anterior thalamic nuclei, the MBs and RSP are key members of a memory circuit, which is usually described as both starting and finishing in the hippocampus. The present findings reveal how the hippocampus simultaneously engages different parts of this circuit, so forcing an important revision of this network. PMID:29527569

Auditory and visual connectivity gradients in frontoparietal cortex.

Science.gov (United States)

Braga, Rodrigo M; Hellyer, Peter J; Wise, Richard J S; Leech, Robert

2017-01-01

A frontoparietal network of brain regions is often implicated in both auditory and visual information processing. Although it is possible that the same set of multimodal regions subserves both modalities, there is increasing evidence that there is a differentiation of sensory function within frontoparietal cortex. Magnetic resonance imaging (MRI) in humans was used to investigate whether different frontoparietal regions showed intrinsic biases in connectivity with visual or auditory modalities. Structural connectivity was assessed with diffusion tractography and functional connectivity was tested using functional MRI. A dorsal-ventral gradient of function was observed, where connectivity with visual cortex dominates dorsal frontal and parietal connections, while connectivity with auditory cortex dominates ventral frontal and parietal regions. A gradient was also observed along the posterior-anterior axis, although in opposite directions in prefrontal and parietal cortices. The results suggest that the location of neural activity within frontoparietal cortex may be influenced by these intrinsic biases toward visual and auditory processing. Thus, the location of activity in frontoparietal cortex may be influenced as much by stimulus modality as the cognitive demands of a task. It was concluded that stimulus modality was spatially encoded throughout frontal and parietal cortices, and was speculated that such an arrangement allows for top-down modulation of modality-specific information to occur within higher-order cortex. This could provide a potentially faster and more efficient pathway by which top-down selection between sensory modalities could occur, by constraining modulations to within frontal and parietal regions, rather than long-range connections to sensory cortices. Hum Brain Mapp 38:255-270, 2017. © 2016 Wiley Periodicals, Inc. © 2016 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.

Development of rat female genital cortex and control of female puberty by sexual touch.

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Constanze Lenschow

2017-09-01

Full Text Available Rat somatosensory cortex contains a large sexually monomorphic genital representation. Genital cortex undergoes an unusual 2-fold expansion during puberty. Here, we investigate genital cortex development and female rat sexual maturation. Ovariectomies and estradiol injections suggested sex hormones cause the pubertal genital cortex expansion but not its maintenance at adult size. Genital cortex expanded by thalamic afferents invading surrounding dysgranular cortex. Genital touch was a dominant factor driving female sexual maturation. Raising female rats in contact with adult males promoted genital cortex expansion, whereas contact to adult females or nontactile (audio-visual-olfactory male cues did not. Genital touch imposed by human experimenters powerfully advanced female genital cortex development and sexual maturation. Long-term blocking of genital cortex by tetrodotoxin in pubescent females housed with males prevented genital cortex expansion and decelerated vaginal opening. Sex hormones, sexual experience, and neural activity shape genital cortex, which contributes to the puberty promoting effects of sexual touch.

Development of rat female genital cortex and control of female puberty by sexual touch.

Science.gov (United States)

Lenschow, Constanze; Sigl-Glöckner, Johanna; Brecht, Michael

2017-09-01

Rat somatosensory cortex contains a large sexually monomorphic genital representation. Genital cortex undergoes an unusual 2-fold expansion during puberty. Here, we investigate genital cortex development and female rat sexual maturation. Ovariectomies and estradiol injections suggested sex hormones cause the pubertal genital cortex expansion but not its maintenance at adult size. Genital cortex expanded by thalamic afferents invading surrounding dysgranular cortex. Genital touch was a dominant factor driving female sexual maturation. Raising female rats in contact with adult males promoted genital cortex expansion, whereas contact to adult females or nontactile (audio-visual-olfactory) male cues did not. Genital touch imposed by human experimenters powerfully advanced female genital cortex development and sexual maturation. Long-term blocking of genital cortex by tetrodotoxin in pubescent females housed with males prevented genital cortex expansion and decelerated vaginal opening. Sex hormones, sexual experience, and neural activity shape genital cortex, which contributes to the puberty promoting effects of sexual touch.

Engagement of the Rat Hindlimb Motor Cortex across Natural Locomotor Behaviors.

Science.gov (United States)

DiGiovanna, Jack; Dominici, Nadia; Friedli, Lucia; Rigosa, Jacopo; Duis, Simone; Kreider, Julie; Beauparlant, Janine; van den Brand, Rubia; Schieppati, Marco; Micera, Silvestro; Courtine, Grégoire

2016-10-05

Contrary to cats and primates, cortical contribution to hindlimb locomotor movements is not critical in rats. However, the importance of the motor cortex to regain locomotion after neurological disorders in rats suggests that cortical engagement in hindlimb motor control may depend on the behavioral context. To investigate this possibility, we recorded whole-body kinematics, muscle synergies, and hindlimb motor cortex modulation in freely moving rats performing a range of natural locomotor procedures. We found that the activation of hindlimb motor cortex preceded gait initiation. During overground locomotion, the motor cortex exhibited consistent neuronal population responses that were synchronized with the spatiotemporal activation of hindlimb motoneurons. Behaviors requiring enhanced muscle activity or skilled paw placement correlated with substantial adjustment in neuronal population responses. In contrast, all rats exhibited a reduction of cortical activity during more automated behavior, such as stepping on a treadmill. Despite the facultative role of the motor cortex in the production of locomotion in rats, these results show that the encoding of hindlimb features in motor cortex dynamics is comparable in rats and cats. However, the extent of motor cortex modulations appears linked to the degree of volitional engagement and complexity of the task, reemphasizing the importance of goal-directed behaviors for motor control studies, rehabilitation, and neuroprosthetics. We mapped the neuronal population responses in the hindlimb motor cortex to hindlimb kinematics and hindlimb muscle synergies across a spectrum of natural locomotion behaviors. Robust task-specific neuronal population responses revealed that the rat motor cortex displays similar modulation as other mammals during locomotion. However, the reduced motor cortex activity during more automated behaviors suggests a relationship between the degree of engagement and task complexity. This relationship

Opponent Coding of Sound Location (Azimuth) in Planum Temporale is Robust to Sound-Level Variations.

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Derey, Kiki; Valente, Giancarlo; de Gelder, Beatrice; Formisano, Elia

2016-01-01

Coding of sound location in auditory cortex (AC) is only partially understood. Recent electrophysiological research suggests that neurons in mammalian auditory cortex are characterized by broad spatial tuning and a preference for the contralateral hemifield, that is, a nonuniform sampling of sound azimuth. Additionally, spatial selectivity decreases with increasing sound intensity. To accommodate these findings, it has been proposed that sound location is encoded by the integrated activity of neuronal populations with opposite hemifield tuning ("opponent channel model"). In this study, we investigated the validity of such a model in human AC with functional magnetic resonance imaging (fMRI) and a phase-encoding paradigm employing binaural stimuli recorded individually for each participant. In all subjects, we observed preferential fMRI responses to contralateral azimuth positions. Additionally, in most AC locations, spatial tuning was broad and not level invariant. We derived an opponent channel model of the fMRI responses by subtracting the activity of contralaterally tuned regions in bilateral planum temporale. This resulted in accurate decoding of sound azimuth location, which was unaffected by changes in sound level. Our data thus support opponent channel coding as a neural mechanism for representing acoustic azimuth in human AC. © The Author 2015. Published by Oxford University Press.

Visual Information Present in Infragranular Layers of Mouse Auditory Cortex.

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Morrill, Ryan J; Hasenstaub, Andrea R

2018-03-14

The cerebral cortex is a major hub for the convergence and integration of signals from across the sensory modalities; sensory cortices, including primary regions, are no exception. Here we show that visual stimuli influence neural firing in the auditory cortex of awake male and female mice, using multisite probes to sample single units across multiple cortical layers. We demonstrate that visual stimuli influence firing in both primary and secondary auditory cortex. We then determine the laminar location of recording sites through electrode track tracing with fluorescent dye and optogenetic identification using layer-specific markers. Spiking responses to visual stimulation occur deep in auditory cortex and are particularly prominent in layer 6. Visual modulation of firing rate occurs more frequently at areas with secondary-like auditory responses than those with primary-like responses. Auditory cortical responses to drifting visual gratings are not orientation-tuned, unlike visual cortex responses. The deepest cortical layers thus appear to be an important locus for cross-modal integration in auditory cortex. SIGNIFICANCE STATEMENT The deepest layers of the auditory cortex are often considered its most enigmatic, possessing a wide range of cell morphologies and atypical sensory responses. Here we show that, in mouse auditory cortex, these layers represent a locus of cross-modal convergence, containing many units responsive to visual stimuli. Our results suggest that this visual signal conveys the presence and timing of a stimulus rather than specifics about that stimulus, such as its orientation. These results shed light on both how and what types of cross-modal information is integrated at the earliest stages of sensory cortical processing. Copyright © 2018 the authors 0270-6474/18/382854-09$15.00/0.

Elevated blood lactate is associated with increased motor cortex excitability.

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Coco, Marinella; Alagona, Giovanna; Rapisarda, Giuseppe; Costanzo, Erminio; Calogero, Roberto Antonio; Perciavalle, Valentina; Perciavalle, Vincenzo

2010-01-01