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Sample records for attention-related cortical functional

  1. Intraoperative determination and display of cortical function

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    Bass, W. Andrew; Galloway, Robert L., Jr.; Dawant, Benoit M.; Maciunas, Robert J.

    1997-05-01

    One of the most important issues in neurosurgical lesion resection is margin definition. And while there is still some effort required to exactly determine lesion boundaries from tomographic images, the lesions are at least perceptible on the scans. What is not visible is the location of function. Functional imaging such as PET and fMRI hold some promise for cortical function localization; however, intraoperative cortical mapping can provide exact localization of function without ambiguity. Since tomographic images can provide lesion margin definition and cortical mapping can provide functional information we have developed a system for combining the two in our Interactive, Image-Guided system. For cortical surface mapping we need a surface description. Brain contours are extracted from a MRI volume using a deformable model approach and rendered from multiple angular positions. As the surgeon moves a probe, its position is displayed on the view closes to the angular position of the probe. During functional mapping, positive response to stimulation result in a color overlay 'dot' added to the cortical surface display. Different colored dots are used to distinguish between motor function and language function. And a third color is used to display overlapping functionality. This information is used to guide the resection around functionally eloquent areas of the cortex.

  2. Functional rehabilitation of partial cortical blindness?

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    Stoerig, Petra

    2008-01-01

    The current doctrine regards fields of partial cortical blindness as permanent once a temporally restricted window for spontaneous recovery has passed. Accordingly, neuropsychological rehabilitation mainly applies compensatory procedures that train patients to make better use of their sighted field. The more ambitious goal of functional recovery depends on the survival of pathways that continue to transmit retinal information from the blind field. Although wide-spread antero- and retrograde degeneration follows lesions that destroy or denervate the primary visual cortex and cause partial cortical blindness, several retinofugal pathways survive in cats, monkeys, and humans. In all three species, they subserve a variety of visual functions which develop and improve with practice. Post lesion plasticity is greater when the lesion occurs early in life, but changes in behavioural performance and brain responses have also been demonstrated in late lesion subjects. Although the extent of functional improvement is variable, and the most effective approaches still need to be established across cohorts, the evidence for perceptual learning in fields of cortical blindness indicates that the visual processes mediated by the surviving parts of the visual system can be harnessed to improve functional outcome.

  3. Functional properties of human auditory cortical fields

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    David L Woods

    2010-12-01

    Full Text Available While auditory cortex in non-human primates has been subdivided into multiple functionally-specialized auditory cortical fields (ACFs, the boundaries and functional specialization of human ACFs have not been defined. In the current study, we evaluated whether a widely accepted primate model of auditory cortex could explain regional tuning properties of fMRI activations on the cortical surface to attended and nonattended tones of different frequency, location, and intensity. The limits of auditory cortex were defined by voxels that showed significant activations to nonattended sounds. Three centrally-located fields with mirror-symmetric tonotopic organization were identified and assigned to the three core fields of the primate model while surrounding activations were assigned to belt fields following procedures similar to those used in macaque fMRI studies. The functional properties of core, medial belt, and lateral belt field groups were then analyzed. Field groups were distinguished by tonotopic organization, frequency selectivity, intensity sensitivity, contralaterality, binaural enhancement, attentional modulation, and hemispheric asymmetry. In general, core fields showed greater sensitivity to sound properties than did belt fields, while belt fields showed greater attentional modulation than core fields. Significant distinctions in intensity sensitivity and contralaterality were seen between adjacent core fields A1 and R, while multiple differences in tuning properties were evident at boundaries between adjacent core and belt fields. The reliable differences in functional properties between fields and field groups suggest that the basic primate pattern of auditory cortex organization is preserved in humans. A comparison of the sizes of functionally-defined ACFs in humans and macaques reveals a significant relative expansion in human lateral belt fields implicated in the processing of speech.

  4. Dopaminergic modulation of cortical function in patients with Parkinson's disease.

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    Mattay, Venkata S; Tessitore, Alessandro; Callicott, Joseph H; Bertolino, Alessandro; Goldberg, Terry E; Chase, Thomas N; Hyde, Thomas M; Weinberger, Daniel R

    2002-02-01

    Patients with idiopathic Parkinson's disease suffer not only from classic motor symptoms, but from deficits in cognitive function, primarily those subserved by the prefrontal cortex as well. The aim of the current study was to investigate the modulatory effects of dopaminergic therapy on neural systems subserving working memory and motor function in patients with Parkinson's disease. Ten patients with stage I and II Parkinson's disease were studied with functional magnetic resonance imaging, during a relatively hypodopaminergic state (ie, 12 hours after a last dose of dopamimetic treatment), and again during a dopamine-replete state. Functional magnetic resonance imaging was performed under three conditions: a working memory task, a cued sensorimotor task and rest. Consistent with prior data, the cortical motor regions activated during the motor task showed greater activation during the dopamine-replete state; however, the cortical regions subserving working memory displayed greater activation during the hypodopaminergic state. Interestingly, the increase in cortical activation during the working memory task in the hypodopaminergic state positively correlated with errors in task performance, and the increased activation in the cortical motor regions during the dopamine-replete state was positively correlated with improvement in motor function. These results support evidence from basic research that dopamine modulates cortical networks subserving working memory and motor function via two distinct mechanisms: nigrostriatal projections facilitate motor function indirectly via thalamic projections to motor cortices, whereas the mesocortical dopaminergic system facilitates working memory function via direct inputs to prefrontal cortex. The results are also consistent with evidence that the hypodopaminergic state is associated with decreased efficiency of prefrontal cortical information processing and that dopaminergic therapy improves the physiological efficiency of

  5. Impaired cortical mitochondrial function following TBI precedes behavioral changes

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    William Doster Watson

    2014-02-01

    Full Text Available Traumatic brain injury (TBI pathophysiology can be attributed to either the immediate, primary physical injury or the delayed, secondary injury which begins minutes to hours after the initial injury and can persist for several months or longer. Because these secondary cascades are delayed and last for a significant time period post TBI, they are primary research targets for new therapeutics. To investigate changes in mitochondrial function after a brain injury, both the cortical impact site and ipsilateral hippocampus of adult male rats 7 and 17 days after a controlled cortical impact (CCI injury were examined. State 3, state 4 and uncoupler-stimulated rates of oxygen consumption, respiratory control ratios were measured and membrane potential quantified, and all were significantly decreased in 7 day post-TBI cortical mitochondria. By contrast, hippocampal mitochondria at 7 days showed only nonsignificant decreases in rates of oxygen consumption and membrane potential. NADH oxidase activities measured in disrupted mitochondria were normal in both injured cortex and hippocampus at 7 days post-CCI. Respiratory and phosphorylation capacities at 17 days post-CCI were comparable to naïve animals for both cortical and hippocampus mitochondria. However, unlike oxidative phosphorylation, membrane potential of mitochondria in the cortical lining of the impact site did not recover at 17 days, suggesting that while diminished cortical membrane potential at 17 days does not adversely affect mitochondrial capacity to synthesize ATP, it may negatively impact other membrane potential-sensitive mitochondrial functions. Memory status, as assessed by a passive avoidance paradim, was not significantly impaired until 17 days after injury. These results indicate pronounced disturbances in cortical mitochondrial function 7 days after CCI which precede the behavioral impairment observed at 17 days.

  6. Functional imaging of cortical feedback projections to the olfactory bulb

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    Markus eRothermel

    2014-07-01

    Full Text Available Processing of sensory information is substantially shaped by centrifugal, or feedback, projections from higher cortical areas, yet the functional properties of these projections are poorly characterized. Here, we used genetically-encoded calcium sensors (GCaMPs to functionally image activation of centrifugal projections targeting the olfactory bulb (OB. The OB receives massive centrifugal input from cortical areas but there has been as yet no characterization of their activity in vivo. We focused on projections to the OB from the anterior olfactory nucleus (AON, a major source of cortical feedback to the OB. We expressed GCaMP selectively in AON projection neurons using a mouse line expressing Cre recombinase (Cre in these neurons and Cre-dependent viral vectors injected into AON, allowing us to image GCaMP fluorescence signals from their axon terminals in the OB. Electrical stimulation of AON evoked large fluorescence signals that could be imaged from the dorsal OB surface in vivo. Surprisingly, odorants also evoked large signals that were transient and coupled to odorant inhalation both in the anesthetized and awake mouse, suggesting that feedback from AON to the OB is rapid and robust across different brain states. The strength of AON feedback signals increased during wakefulness, suggesting a state-dependent modulation of cortical feedback to the OB. Two-photon GCaMP imaging revealed that different odorants activated different subsets of centrifugal AON axons and could elicit both excitation and suppression in different axons, indicating a surprising richness in the representation of odor information by cortical feedback to the OB. Finally, we found that activating neuromodulatory centers such as basal forebrain drove AON inputs to the OB independent of odorant stimulation. Our results point to the AON as a multifunctional cortical area that provides ongoing feedback to the OB and also serves as a descending relay for other neuromodulatory

  7. Functional neural substrates of posterior cortical atrophy patients.

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    Shames, H; Raz, N; Levin, Netta

    2015-07-01

    Posterior cortical atrophy (PCA) is a neurodegenerative syndrome in which the most pronounced pathologic involvement is in the occipito-parietal visual regions. Herein, we aimed to better define the cortical reflection of this unique syndrome using a thorough battery of behavioral and functional MRI (fMRI) tests. Eight PCA patients underwent extensive testing to map their visual deficits. Assessments included visual functions associated with lower and higher components of the cortical hierarchy, as well as dorsal- and ventral-related cortical functions. fMRI was performed on five patients to examine the neuronal substrate of their visual functions. The PCA patient cohort exhibited stereopsis, saccadic eye movements and higher dorsal stream-related functional impairments, including simultant perception, image orientation, figure-from-ground segregation, closure and spatial orientation. In accordance with the behavioral findings, fMRI revealed intact activation in the ventral visual regions of face and object perception while more dorsal aspects of perception, including motion and gestalt perception, revealed impaired patterns of activity. In most of the patients, there was a lack of activity in the word form area, which is known to be linked to reading disorders. Finally, there was evidence of reduced cortical representation of the peripheral visual field, corresponding to the behaviorally assessed peripheral visual deficit. The findings are discussed in the context of networks extending from parietal regions, which mediate navigationally related processing, visually guided actions, eye movement control and working memory, suggesting that damage to these networks might explain the wide range of deficits in PCA patients.

  8. [Research advances on cortical functional and structural deficits of amblyopia].

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    Wu, Y; Liu, L Q

    2017-05-11

    Previous studies have observed functional deficits in primary visual cortex. With the development of functional magnetic resonance imaging and electrophysiological technique, the research of the striate, extra-striate cortex and higher-order cortical deficit underlying amblyopia reaches a new stage. The neural mechanisms of amblyopia show that anomalous responses exist throughout the visual processing hierarchy, including the functional and structural abnormalities. This review aims to summarize the current knowledge about structural and functional deficits of brain regions associated with amblyopia. (Chin J Ophthalmol, 2017, 53: 392-395).

  9. The enemy within: propagation of aberrant corticostriatal learning to cortical function in Parkinson's disease

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    Jeff A Beeler

    2013-09-01

    Full Text Available Motor dysfunction in Parkinson’s disease is believed to arise primarily from pathophysiology in the dorsal striatum and its related corticostriatal and thalamostriatal circuits during progressive dopamine denervation. One function of these circuits is to provide a filter that selectively facilitates or inhibits cortical activity to optimize cortical processing, making motor responses rapid and efficient. Corticostriatal synaptic plasticity mediates the learning that underlies this performance-optimizing filter. Under dopamine denervation, corticostriatal plasticity is altered, resulting in aberrant learning that induces inappropriate basal ganglia filtering that impedes rather than optimizes cortical processing. Human imaging suggests that increased cortical activity may compensate for striatal dysfunction in PD patients. In this Perspective article, we consider how aberrant learning at corticostriatal synapses may impair cortical processing and learning and undermine potential cortical compensatory mechanisms. Blocking or remediating aberrant corticostriatal plasticity may protect cortical function and support cortical compensatory mechanisms mitigating the functional decline associated with progressive dopamine denervation.

  10. Functional Connectivity of the Cortical Swallowing Network in Humans

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    Babaei, Arash; Ward, B. Douglas; Siwiec, Robert; Ahmad, Shahryar; Kern, Mark; Nencka, Andrew; Li, Shi-Jiang; Shaker, Reza

    2014-01-01

    Introduction Coherent fluctuations of blood oxygenation level dependent (BOLD) signal have been referred as “functional connectivity” (FC). Our aim was to systematically characterize FC of underlying neural network involved in swallowing, and to evaluate its reproducibility and modulation during rest or task performance. Methods Activated seed regions within known areas of the cortical swallowing network (CSN) were independently identified in 16 healthy volunteers. Subjects swallowed using a paradigm driven protocol, and the data analyzed using an event-related technique. Then, in the same 16 volunteers, resting and active state data were obtained for 540 seconds in three conditions: 1) swallowing task; 2) control visual task; and 3) resting state; all scans were performed twice. Data was preprocessed according to standard FC pipeline. We determined the correlation coefficient values of member regions of the CSN across the three aforementioned conditions and compared between two sessions using linear regression. Average FC matrices across conditions were then compared. Results Swallow activated twenty-two positive BOLD and eighteen negative BOLD regions distributed bilaterally within cingulate, insula, sensorimotor cortex, prefrontal and parietal cortices. We found that: 1) Positive BOLD regions were highly connected to each other during all test conditions while negative BOLD regions were tightly connected amongst themselves; 2) Positive and negative BOLD regions were anti-correlated at rest and during task performance; 3) Across all three test conditions, FC among the regions was reproducible (r > 0.96, p<10-5); and 4) The FC of sensorimotor region to other regions of the CSN increased during swallowing scan. Conclusions 1) Swallow activated cortical substrates maintain a consistent pattern of functional connectivity; 2) FC of sensorimotor region is significantly higher during swallow scan than that observed during a non-swallow visual task or at rest. PMID

  11. [Preoperative direct cortical and sub-cortical electric stimulation during cerebral surgery in functional areas].

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    Duffau, H; Capelle, L; Sichez, J P; Bitar, A; Faillot, T; Arthuis, F; Van Effenterre, R; Fohanno, D

    1999-09-01

    Indications of surgical treatment for lesions in functional cerebral areas depend on the ratio between the definitive neurological deficit and the beneficial effect of resection. Detection of eloquent cortex is difficult because of important individual variability. Peroperative direct cortical and subcortical electrical stimulations (DCS) provide the most precise and reliable method currently available allowing identification and preservation of neurons essential for motricity, sensitivity++ and language. We report our preliminary experience with DCS in surgery of intracerebral infiltrative tumors with a consecutive series of 15 patients operated from November 96 through September 97 in our institution. Presenting symptoms in the 15 patients (8 males, 7 females, mean age 43 years) were seizures in 11 cases (73%) and neurological deficit in 4 cases (27%). Clinical examination was normal in 11 patients and revealed hemiparesia in 4. Magnetic resonance imaging (MRI) with three-dimensional reconstruction showed a precentral tumor in 10 cases, central lesion in one patient, postcentral lesion in two cases, right insular tumor (non-dominant hemisphere) in one case. All patients underwent surgical resection using DCS with detection in 13 cases of motor cortex and subcortical pathways under genera anesthesia, in one case of somatosensory area under local anesthesia, and in one case of language areas also under local anesthesia. The tumor was recurrent in two patients had been operated earlier but without DCS. Resection, verified by postoperative MRI, was total in 12 cases (80%) and estimated at 80% in 3 patients. Histological examination revealed an infiltrative glioma in 12 cases (8 low grade astrocytomas, 3 low grade oligodendrogliomas, and one anaplastic oligodendroglioma), and metastases in 3 cases. Eight patients had no postoperative deficit, while the other 7 patients were impaired, with, in all cases except one, complete recovery in 15 days to 2 months. Direct

  12. Mitochondrial activity and brain functions during cortical depolarization

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    Mayevsky, Avraham; Sonn, Judith

    2008-12-01

    Cortical depolarization (CD) of the cerebral cortex could be developed under various pathophysiological conditions. In animal models, CD was recorded under partial or complete ischemia as well as when cortical spreading depression (SD) was induced externally or by internal stimulus. The development of CD in patients and the changes in various metabolic parameters, during CD, was rarely reported. Brain metabolic, hemodynamic, ionic and electrical responses to the CD event are dependent upon the O2 balance in the tissue. When the O2 balance is negative (i.e. ischemia), the CD process will be developed due to mitochondrial dysfunction, lack of energy and the inhibition of Na+-K+-ATPase. In contradiction, when oxygen is available (i.e. normoxia) the development of CD after induction of SD will accelerate mitochondrial respiration for retaining ionic homeostasis and normal brain functions. We used the multiparametric monitoring approach that enable real time monitoring of mitochondrial NADH redox state, microcirculatory blood flow and oxygenation, extracellular K+, Ca2+, H+ levels, DC steady potential and electrocorticogram (ECoG). This monitoring approach, provide a unique tool that has a significant value in analyzing the pathophysiology of the brain when SD developed under normoxia, ischemia, or hypoxia. We applied the same monitoring approach to patients suffered from severe head injury or exposed to neurosurgical procedures.

  13. Functional cortical network in alpha band correlates with social bargaining.

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    Pablo Billeke

    Full Text Available Solving demanding tasks requires fast and flexible coordination among different brain areas. Everyday examples of this are the social dilemmas in which goals tend to clash, requiring one to weigh alternative courses of action in limited time. In spite of this fact, there are few studies that directly address the dynamics of flexible brain network integration during social interaction. To study the preceding, we carried out EEG recordings while subjects played a repeated version of the Ultimatum Game in both human (social and computer (non-social conditions. We found phase synchrony (inter-site-phase-clustering modulation in alpha band that was specific to the human condition and independent of power modulation. The strength and patterns of the inter-site-phase-clustering of the cortical networks were also modulated, and these modulations were mainly in frontal and parietal regions. Moreover, changes in the individuals' alpha network structure correlated with the risk of the offers made only in social conditions. This correlation was independent of changes in power and inter-site-phase-clustering strength. Our results indicate that, when subjects believe they are participating in a social interaction, a specific modulation of functional cortical networks in alpha band takes place, suggesting that phase synchrony of alpha oscillations could serve as a mechanism by which different brain areas flexibly interact in order to adapt ongoing behavior in socially demanding contexts.

  14. An anatomical and functional topography of human auditory cortical areas

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    Michelle eMoerel

    2014-07-01

    Full Text Available While advances in magnetic resonance imaging (MRI throughout the last decades have enabled the detailed anatomical and functional inspection of the human brain non-invasively, to date there is no consensus regarding the precise subdivision and topography of the areas forming the human auditory cortex. Here, we propose a topography of the human auditory areas based on insights on the anatomical and functional properties of human auditory areas as revealed by studies of cyto- and myelo-architecture and fMRI investigations at ultra-high magnetic field (7 Tesla. Importantly, we illustrate that - whereas a group-based approach to analyze functional (tonotopic maps is appropriate to highlight the main tonotopic axis - the examination of tonotopic maps at single subject level is required to detail the topography of primary and non-primary areas that may be more variable across subjects. Furthermore, we show that considering multiple maps indicative of anatomical (i.e. myelination as well as of functional properties (e.g. broadness of frequency tuning is helpful in identifying auditory cortical areas in individual human brains. We propose and discuss a topography of areas that is consistent with old and recent anatomical post mortem characterizations of the human auditory cortex and that may serve as a working model for neuroscience studies of auditory functions.

  15. Control of Somatosensory Cortical Processing by Thalamic Posterior Medial Nucleus: A New Role of Thalamus in Cortical Function.

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    Carlos Castejon

    Full Text Available Current knowledge of thalamocortical interaction comes mainly from studying lemniscal thalamic systems. Less is known about paralemniscal thalamic nuclei function. In the vibrissae system, the posterior medial nucleus (POm is the corresponding paralemniscal nucleus. POm neurons project to L1 and L5A of the primary somatosensory cortex (S1 in the rat brain. It is known that L1 modifies sensory-evoked responses through control of intracortical excitability suggesting that L1 exerts an influence on whisker responses. Therefore, thalamocortical pathways targeting L1 could modulate cortical firing. Here, using a combination of electrophysiology and pharmacology in vivo, we have sought to determine how POm influences cortical processing. In our experiments, single unit recordings performed in urethane-anesthetized rats showed that POm imposes precise control on the magnitude and duration of supra- and infragranular barrel cortex whisker responses. Our findings demonstrated that L1 inputs from POm imposed a time and intensity dependent regulation on cortical sensory processing. Moreover, we found that blocking L1 GABAergic inhibition or blocking P/Q-type Ca2+ channels in L1 prevents POm adjustment of whisker responses in the barrel cortex. Additionally, we found that POm was also controlling the sensory processing in S2 and this regulation was modulated by corticofugal activity from L5 in S1. Taken together, our data demonstrate the determinant role exerted by the POm in the adjustment of somatosensory cortical processing and in the regulation of cortical processing between S1 and S2. We propose that this adjustment could be a thalamocortical gain regulation mechanism also present in the processing of information between cortical areas.

  16. Population spikes in cortical networks during different functional states.

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    Shirley eMark

    2012-07-01

    Full Text Available Brain computational challenges vary between behavioral states. Engaged animals react according to incoming sensory information, while in relaxed and sleeping states consolidation of the learned information is believed to take place. Different states are characterized by different forms of cortical activity. We study a possible neuronal mechanism for generating these diverse dynamics and suggest their possible functional significance. Previous studies demonstrated that brief synchronized increase in a neural firing (Population Spikes can be generated in homogenous recurrent neural networks with short-term synaptic depression. Here we consider more realistic networks with clustered architecture. We show that the level of synchronization in neural activity can be controlled smoothly by network parameters. The network shifts from asynchronous activity to a regime in which clusters synchronized separately, then, the synchronization between the clusters increases gradually to fully synchronized state. We examine the effects of different synchrony levels on the transmission of information by the network. We find that the regime of intermediate synchronization is preferential for the flow of information between sparsely connected areas. Based on these results, we suggest that the regime of intermediate synchronization corresponds to engaged behavioral state of the animal, while global synchronization is exhibited during relaxed and sleeping states.

  17. Refractory hypoglycemia in a patient with functional adrenal cortical carcinoma

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    Katia Regina Marchetti

    2016-11-01

    Full Text Available Adrenacarcinomas are rare, and hypoglycemic syndrome resulting from the secretion of insulin-like growth factor II (IGF-II by these tumors have been described infrequently. This study describes the case of a young woman with severe persistent hypoglycemia and a large adrenal tumor and discusses the physiopathological mechanisms involved in hypoglycemia. The case is described as a 21-year-old woman who presented with 8 months of general symptoms and, in the preceding 3 months, with episodes of mental confusion and visual blurring secondary to hypoglycemia. A functional assessment of the adrenal cortex revealed ACTH-independent hypercortisolism and hyperandrogenism. Hypoglycemia, hypoinsulinemia, low C-peptide and no ketones were also detected. An evaluation of the GH–IGF axis revealed GH blockade (0.03; reference: up to 4.4 ng/mL, greatly reduced IGF-I levels (9.0 ng/mL; reference: 180–780 ng/mL, slightly reduced IGF-II levels (197 ng/mL; reference: 267–616 ng/mL and an elevated IGF-II/IGF-I ratio (21.9; reference: ~3. CT scan revealed a large expansive mass in the right adrenal gland and pulmonary and liver metastases. During hospitalization, the patient experienced frequent difficult-to-control hypoglycemia and hypokalemia episodes. Octreotide was ineffective in controlling hypoglycemia. Due to unresectability, chemotherapy was tried, but after 3 months, the patient’s condition worsened and progressed to death. In conclusion, our patient presented with a functional adrenal cortical carcinoma, with hyperandrogenism associated with hypoinsulinemic hypoglycemia and blockage of the GH–IGF-I axis. Patient’s data suggested a diagnosis of hypoglycemia induced by an IGF-II or a large IGF-II-producing tumor (low levels of GH, greatly decreased IGF-I, slightly decreased IGF-II and an elevated IGF-II/IGF-I ratio.

  18. Intra-operative multi-site stimulation: Expanding methodology for cortical brain mapping of language functions.

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    Gonen, Tal; Gazit, Tomer; Korn, Akiva; Kirschner, Adi; Perry, Daniella; Hendler, Talma; Ram, Zvi

    2017-01-01

    Direct cortical stimulation (DCS) is considered the gold-standard for functional cortical mapping during awake surgery for brain tumor resection. DCS is performed by stimulating one local cortical area at a time. We present a feasibility study using an intra-operative technique aimed at improving our ability to map brain functions which rely on activity in distributed cortical regions. Following standard DCS, Multi-Site Stimulation (MSS) was performed in 15 patients by applying simultaneous cortical stimulations at multiple locations. Language functioning was chosen as a case-cognitive domain due to its relatively well-known cortical organization. MSS, performed at sites that did not produce disruption when applied in a single stimulation point, revealed additional language dysfunction in 73% of the patients. Functional regions identified by this technique were presumed to be significant to language circuitry and were spared during surgery. No new neurological deficits were observed in any of the patients following surgery. Though the neuro-electrical effects of MSS need further investigation, this feasibility study may provide a first step towards sophistication of intra-operative cortical mapping.

  19. Cognitive function, P3a/P3b brain potentials, and cortical thickness in aging.

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    Fjell, Anders M; Walhovd, Kristine B; Fischl, Bruce; Reinvang, Ivar

    2007-11-01

    The purpose of the study was to assess the relationship between the P3a/P3b brain potentials, cortical thickness, and cognitive function in aging. Thirty-five younger and 37 older healthy participants completed a visual three-stimuli oddball ERP (event-related potential)-paradigm, a battery of neuropsychological tests, and MRI scans. Groups with short vs. long latency, and low vs. high amplitude, were compared on a point by point basis across the entire cortical mantle. In the young, thickness was only weakly related to P3. In the elderly, P3a amplitude effects were found in parietal areas, the temporoparietal junction, and parts of the posterior cingulate cortex. P3b latency was especially related to cortical thickness in large frontal regions. Path models with the whole sample pooled together were constructed, demonstrating that cortical thickness in the temporoparietal cortex predicted P3a amplitude, which in turn predicted executive function, and that thickness in orbitofrontal cortex predicted P3b latency, which in turn predicted fluid function. When age was included in the model, the relationship between P3 and cognitive function vanished, while the relationship between regional cortical thickness and P3 remained. It is concluded that thickness in specific cortical areas correlates with scalp recorded P3a/P3b in elderly, and that these relationships differentially mediate higher cognitive function. Copyright 2007 Wiley-Liss, Inc.

  20. Structural and functional evaluation of cortical motor areas in Amyotrophic Lateral Sclerosis.

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    Cosottini, Mirco; Pesaresi, Ilaria; Piazza, Selina; Diciotti, Stefano; Cecchi, Paolo; Fabbri, Serena; Carlesi, Cecilia; Mascalchi, Mario; Siciliano, Gabriele

    2012-03-01

    The structural and functional data gathered with Magnetic Resonance Imaging (MRI) techniques about the brain cortical motor damage in Amyotrophic Lateral Sclerosis (ALS) are controversial. In fact some structural MRI studies showed foci of gray matter (GM) atrophy in the precentral gyrus, even in the early stage, while others did not. Most functional MRI (fMRI) studies in ALS reported hyperactivation of extra-primary motor cortices, while contradictory results were obtained on the activation of the primary motor cortex. We aimed to investigate the cortical motor circuitries in ALS patients by a combined structural and functional approach. Twenty patients with definite ALS and 16 healthy subjects underwent a structural examination with acquisition of a 3D T1-weighted sequence and fMRI examination during a maximal force handgrip task executed with the right-hand, the left-hand and with both hands simultaneously. The T1-weighted images were analyzed with Voxel-Based Morphometry (VBM) that showed several clusters of reduced cortical GM in ALS patients compared to controls including the pre and postcentral gyri, the superior, middle and inferior frontal gyri, the supplementary motor area, the superior and inferior parietal cortices and the temporal lobe, bilaterally but more extensive on the right side. In ALS patients a significant hypoactivation of the primary sensory motor cortex and frontal dorsal premotor areas as compared to controls was observed. The hypoactivated areas matched with foci of cortical atrophy demonstrated by VBM. The fMRI analysis also showed an enhanced activation in the ventral premotor frontal areas and in the parietal cortex pertaining to the fronto-parietal motor circuit which paralleled with disease progression rate and matched with cortical regions of atrophy. The hyperactivation of the fronto-parietal circuit was asymmetric and prevalent in the left hemisphere. VBM and fMRI identified structural and functional markers of an extended

  1. The Reliability of the CVI Range: A Functional Vision Assessment for Children with Cortical Visual Impairment

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    Newcomb, Sandra

    2010-01-01

    Children who are identified as visually impaired frequently have a functional vision assessment as one way to determine how their visual impairment affects their educational performance. The CVI Range is a functional vision assessment for children with cortical visual impairment. The purpose of the study presented here was to examine the…

  2. Distribution of neurons in functional areas of the mouse cerebral cortex reveals quantitatively different cortical zones

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    Herculano-Houzel, Suzana; Watson, Charles; Paxinos, George

    2013-01-01

    How are neurons distributed along the cortical surface and across functional areas? Here we use the isotropic fractionator (Herculano-Houzel and Lent, 2005) to analyze the distribution of neurons across the entire isocortex of the mouse, divided into 18 functional areas defined anatomically. We find that the number of neurons underneath a surface area (the N/A ratio) varies 4.5-fold across functional areas and neuronal density varies 3.2-fold. The face area of S1 contains the most neurons, followed by motor cortex and the primary visual cortex. Remarkably, while the distribution of neurons across functional areas does not accompany the distribution of surface area, it mirrors closely the distribution of cortical volumes—with the exception of the visual areas, which hold more neurons than expected for their volume. Across the non-visual cortex, the volume of individual functional areas is a shared linear function of their number of neurons, while in the visual areas, neuronal densities are much higher than in all other areas. In contrast, the 18 functional areas cluster into three different zones according to the relationship between the N/A ratio and cortical thickness and neuronal density: these three clusters can be called visual, sensory, and, possibly, associative. These findings are remarkably similar to those in the human cerebral cortex (Ribeiro et al., 2013) and suggest that, like the human cerebral cortex, the mouse cerebral cortex comprises two zones that differ in how neurons form the cortical volume, and three zones that differ in how neurons are distributed underneath the cortical surface, possibly in relation to local differences in connectivity through the white matter. Our results suggest that beyond the developmental divide into visual and non-visual cortex, functional areas initially share a common distribution of neurons along the parenchyma that become delimited into functional areas according to the pattern of connectivity established later

  3. Distribution of neurons in functional areas of the mouse cerebral cortex reveals quantitatively different cortical zones

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    Suzana eHerculano-Houzel

    2013-10-01

    Full Text Available How are neurons distributed along the cortical surface and across functional areas? Here we use the isotropic fractionator (Herculano-Houzel and Lent, 2005 to analyze the distribution of neurons across the entire isocortex of the mouse, divided into 18 functional areas defined anatomically. We find that the number of neurons underneath a surface area (the N/A ratio varies 4.5-fold across functional areas and neuronal density varies 3.2-fold. The face area of S1 contains the most neurons, followed by motor cortex and the primary visual cortex. Remarkably, while the distribution of neurons across functional areas does not accompany the distribution of surface area, it mirrors closely the distribution of cortical volumes – with the exception of the visual areas, which hold more neurons than expected for their volume. Across the non-visual cortex, the volume of individual functional areas is a shared linear function of their number of neurons, while in the visual areas, neuronal densities are much higher than in all other areas. In contrast, the 18 functional areas cluster into three different zones according to the relationship between the N/A ratio and cortical thickness and neuronal density: these three clusters can be called visual, sensory, and, possibly, associative. These findings are remarkably similar to those in the human cerebral cortex (see companion paper and suggest that, like the human cerebral cortex, the mouse cerebral cortex comprises two zones that differ in how neurons form the cortical volume, and three zones that differ in how neurons are distributed underneath the cortical surface, possibly in relation to local differences in connectivity through the white matter. Our results suggest that beyond the developmental divide into visual and non-visual cortex, functional areas initially share a common distribution of neurons along the parenchyma that become delimited into functional areas according to the pattern of connectivity

  4. Brain functional connectome abnormalities in amyotrophic lateral sclerosis are associated with disability and cortical hyperexcitability.

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    Geevasinga, N; Korgaonkar, M S; Menon, P; Van den Bos, M; Gomes, L; Foster, S; Kiernan, M C; Vucic, S

    2017-12-01

    The present study utilized a multimodal approach encompassing connectome networks combined with brain volume analysis, and assessment of cortical excitability to provide novel insights into amyotrophic lateral sclerosis (ALS) pathogenesis. Magnetic resonance images were acquired using a 3.0-Tesla Signa HDx scanner (GE Healthcare, Milwaukee, WI, USA), using an eight-channel head coil. Magnetic resonance images for the resting-state scan were acquired using an echo-planar imaging magnetic resonance sequence, acquiring 40 contiguous axial/oblique slices. Structural magnetic resonance imaging three-dimensional T1-weighted images were acquired in the sagittal plane using three-dimensional spoiled gradient echo sequences. For structural imaging, a T1-weighted high-resolution (3.0-Tesla) magnetic resonance imaging scan was used. Cortical excitability was assessed by using the threshold-tracking transcranial magnetic stimulation paradigm. Network-based statistics and whole-brain functional topology (using graph theoretical approaches) assessed functional connectivity. Using a global network-based statistical analysis approach, functional connectivity was increased in 12 network edges connecting 14 nodes (P < 0.05) within the frontal, temporal, parietal and subcortical regions. Analysis of local connectedness disclosed dichotomous effects with reduced connectivity in frontal regions and increased connectivity in occipital regions in ALS. Cortical hyperexcitability was evident in patients with ALS, negatively correlated with functional connectivity changes in the pre-central gyrus (P < 0.01). Connectivity changes in the frontal regions were negatively associated with functional disability (P < 0.05). Multimodal assessment of cortical function in patients with ALS identified deficits in functional connectivity associated with cortical hyperexcitability that correlated with patient disability. Novel integration of functional brain assessment further contributes to the

  5. Cortical arousal in children and adolescents with functional neurological symptoms during the auditory oddball task

    Directory of Open Access Journals (Sweden)

    Kasia Kozlowska, MBBS., PhD. FRANZCP

    2017-01-01

    Conclusions: Our findings add to a growing literature indicating that a baseline state of high arousal may be a precondition for generating functional neurological symptoms, a finding that helps explain why a range of psychological and physiological stressors can trigger functional neurological symptoms in some patients. Interventions that target cortical arousal may be central to the treatment of paediatric patients with functional neurological symptom disorder.

  6. The Role of Cortical Plasticity in Recovery of Function Following Allogeneic Hand Transplantation

    Science.gov (United States)

    2016-10-01

    frontal cortical networks involved in visually- guided grasping of objects, and these patterns appear related to recovery of functional hand use. 4...decade following hand transplantation, long after the expected completion of peripheral nerve regeneration . Developing a more complete...composite tissue transplantation. This project will yield new insights of fundamental relevance to improving the care and rehabilitation of transplant

  7. Cortical plasticity and olfactory function in early blindness.

    Directory of Open Access Journals (Sweden)

    Rodrigo Araneda

    2016-08-01

    Full Text Available Over the last decade, functional brain imaging has provided insight in the maturation processes and has helped elucidate the pathophysiological mechanisms involved in brain plasticity in the absence of vision. In case of congenital blindness, drastic changes occur within the deafferented visual cortex that starts receiving and processing nonvisual inputs, including olfactory stimuli. This functional reorganization of the occipital cortex gives rise to compensatory perceptual and cognitive mechanisms that help blind persons to achieve perceptual tasks, leading to superior olfactory abilities in these subjects. This view receives support from psychophysical testing, volumetric measurements and functional brain imaging studies in humans, which are presented here.

  8. Personality functioning and the cortical midline structures--an exploratory FMRI study.

    Directory of Open Access Journals (Sweden)

    Stephan Doering

    Full Text Available OBJECTIVE: Recent neuroscience studies explored the neuronal mechanisms underlying our sense of self. Thereby the cortical midline structures and their anterior and posterior regions have been shown to be central. What remains unclear though is how both, self and cortical midline structures, are related to the identity of the self which is of central importance in especially personality disorders. METHODS: Conducting an exploratory study with a dimensional approach, we here compared subjects with high and low level of personality functioning and identity integration as measured in a standardized way in fMRI during both, emotion- and reward-related tasks. RESULTS: Low levels of personality functioning and identity integration were predicted by significantly decreased degrees of deactivation in the anterior and posterior cortical midline structures. CONCLUSIONS: Though exploratory our results show for the first time direct relationship between cortical midline structures and personality functioning in terms of identity integration. This does not only contribute to our understanding of the neuronal mechanism underlying self and identity but carries also major implications for the treatment of patients with personality disorders.

  9. Cortical Mechanisms of Tongue Sensorimotor Functions in Humans: A Review of the Magnetoencephalography Approach

    Science.gov (United States)

    Maezawa, Hitoshi

    2017-01-01

    The tongue plays important roles in a variety of critical human oral functions, including speech production, swallowing, mastication and respiration. These sophisticated tongue movements are in part finely regulated by cortical entrainment. Many studies have examined sensorimotor processing in the limbs using magnetoencephalography (MEG), which has high spatiotemporal resolution. Such studies have employed multiple methods of analysis, including somatosensory evoked fields (SEFs), movement-related cortical fields (MRCFs), event-related desynchronization/synchronization (ERD/ERS) associated with somatosensory stimulation or movement and cortico-muscular coherence (CMC) during sustained movement. However, the cortical mechanisms underlying the sensorimotor functions of the tongue remain unclear, as contamination artifacts induced by stimulation and/or muscle activity within the orofacial region complicates MEG analysis in the oral region. Recently, several studies have obtained MEG recordings from the tongue region using improved stimulation methods and movement tasks. In the present review, we provide a detailed overview of tongue sensorimotor processing in humans, based on the findings of recent MEG studies. In addition, we review the clinical applications of MEG for sensory disturbances of the tongue caused by damage to the lingual nerve. Increased knowledge of the physiological and pathophysiological mechanisms underlying tongue sensorimotor processing may improve our understanding of the cortical entrainment of human oral functions. PMID:28400725

  10. Mind the blind brain to understand the sighted one! Is there a supramodal cortical functional architecture?

    Science.gov (United States)

    Ricciardi, Emiliano; Bonino, Daniela; Pellegrini, Silvia; Pietrini, Pietro

    2014-04-01

    While most of the research in blind individuals classically has focused on the compensatory plastic rearrangements that follow loss of sight, novel behavioral, anatomical and functional brain studies in individuals born deprived of sight represent a powerful tool to understand to what extent the brain functional architecture is programmed to develop independently from any visual experience. Here we review work from our lab and others, conducted in sighted and congenitally blind individuals, whose results indicate that vision is not a mandatory prerequisite for the brain cortical organization to develop and function. Similar cortical networks subtend visual and/or non-visual perception of form, space and movement, as well as action recognition, both in sighted and in congenitally blind individuals. These findings support the hypothesis of a modality independent, supramodal cortical organization. Visual experience, however, does play a role in shaping specific cortical sub-regions, as loss of sight is accompanied also by cross-modal plastic phenomena. Altogether, studying the blind brain is opening our eyes on how the brain develops and works. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. The value of preoperative functional cortical mapping using navigated TMS.

    Science.gov (United States)

    Lefaucheur, Jean-Pascal; Picht, Thomas

    2016-04-01

    The surgical removal of brain tumours in so-called eloquent regions is frequently associated with a high risk of causing disabling postoperative deficits. Among the preoperative techniques proposed to help neurosurgical planning and procedure, navigated transcranial magnetic stimulation (nTMS) is increasingly performed. A high level of evidence is now available in the literature regarding the anatomical and functional accuracy of this mapping technique. This article presents the principles and facts demonstrating the value of using nTMS in clinical practice to preserve motor or language functions from deleterious lesions secondary to brain tumour resection or epilepsy surgery. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  12. Cortical functional hyperconnectivity in a mouse model of depression and selective network effects of ketamine.

    Science.gov (United States)

    McGirr, Alexander; LeDue, Jeffrey; Chan, Allen W; Xie, Yicheng; Murphy, Timothy H

    2017-08-01

    See Huang and Liston (doi:10.1093/awx166) for a scientific commentary on this article.Human depression is associated with glutamatergic dysfunction and alterations in resting state network activity. However, the indirect nature of human in vivo glutamate and activity assessments obscures mechanistic details. Using the chronic social defeat mouse model of depression, we determine how mesoscale glutamatergic networks are altered after chronic stress, and in response to the rapid acting antidepressant, ketamine. Transgenic mice (Ai85) expressing iGluSnFR (a recombinant protein sensor) permitted real-time in vivo selective characterization of extracellular glutamate and longitudinal imaging of mesoscale cortical glutamatergic functional circuits. Mice underwent chronic social defeat or a control condition, while spontaneous cortical activity was longitudinally sampled. After chronic social defeat, we observed network-wide glutamate functional hyperconnectivity in defeated animals, which was confirmed with voltage sensitive dye imaging in an independent cohort. Subanaesthetic ketamine has unique effects in defeated animals. Acutely, subanaesthetic ketamine induces large global cortical glutamate transients in defeated animals, and an elevated subanaesthetic dose resulted in sustained global increase in cortical glutamate. Local cortical inhibition of glutamate transporters in naïve mice given ketamine produced a similar extracellular glutamate phenotype, with both glutamate transients and a dose-dependent accumulation of glutamate. Twenty-four hours after ketamine, normalization of depressive-like behaviour in defeated animals was accompanied by reduced glutamate functional connectivity strength. Altered glutamate functional connectivity in this animal model confirms the central role of glutamate dynamics as well as network-wide changes after chronic stress and in response to ketamine. © The Author (2017). Published by Oxford University Press on behalf of the

  13. Altered Cortical Swallowing Processing in Patients with Functional Dysphagia: A Preliminary Study

    Science.gov (United States)

    Wollbrink, Andreas; Warnecke, Tobias; Winkels, Martin; Pantev, Christo; Dziewas, Rainer

    2014-01-01

    Objective Current neuroimaging research on functional disturbances provides growing evidence for objective neuronal correlates of allegedly psychogenic symptoms, thereby shifting the disease concept from a psychological towards a neurobiological model. Functional dysphagia is such a rare condition, whose pathogenetic mechanism is largely unknown. In the absence of any organic reason for a patient's persistent swallowing complaints, sensorimotor processing abnormalities involving central neural pathways constitute a potential etiology. Methods In this pilot study we measured cortical swallow-related activation in 5 patients diagnosed with functional dysphagia and a matched group of healthy subjects applying magnetoencephalography. Source localization of cortical activation was done with synthetic aperture magnetometry. To test for significant differences in cortical swallowing processing between groups, a non-parametric permutation test was afterwards performed on individual source localization maps. Results Swallowing task performance was comparable between groups. In relation to control subjects, in whom activation was symmetrically distributed in rostro-medial parts of the sensorimotor cortices of both hemispheres, patients showed prominent activation of the right insula, dorsolateral prefrontal cortex and lateral premotor, motor as well as inferolateral parietal cortex. Furthermore, activation was markedly reduced in the left medial primary sensory cortex as well as right medial sensorimotor cortex and adjacent supplementary motor area (pdysphagia - a condition with assumed normal brain function - seems to be associated with distinctive changes of the swallow-related cortical activation pattern. Alterations may reflect exaggerated activation of a widely distributed vigilance, self-monitoring and salience rating network that interferes with down-stream deglutition sensorimotor control. PMID:24586948

  14. Excitability of motor cortices as a function of emotional sounds.

    Science.gov (United States)

    Komeilipoor, Naeem; Pizzolato, Fabio; Daffertshofer, Andreas; Cesari, Paola

    2013-01-01

    We used transcranial magnetic stimulation (TMS) to clarify how non-verbal emotionally-characterized sounds modulate the excitability of the corticospinal motor tract (CST). While subjects were listening to sounds (monaurally and binaurally), single TMS pulses were delivered to either left or right primary motor cortex (M1), and electromyographic activities were recorded from the contralateral abductor pollicis brevis muscle. We found a significant increase in CST excitability in response to unpleasant as compared to neutral sounds. The increased excitability was lateralized as a function of stimulus valence: Unpleasant stimuli resulted in a significantly higher facilitation of motor potentials evoked in the left hemisphere, while pleasant stimuli yielded a greater CST excitability in the right one. Furthermore, TMS induced higher motor evoked potentials when listening to unpleasant sounds with the left than with the right ear. Taken together, our findings provide compelling evidence for an asymmetric modulation of CST excitability as a function of emotional sounds along with ear laterality.

  15. [Cortical blindness].

    Science.gov (United States)

    Chokron, S

    2014-02-01

    Cortical blindness refers to a visual loss induced by a bilateral occipital lesion. The very strong cooperation between psychophysics, cognitive psychology, neurophysiology and neuropsychology these latter twenty years as well as recent progress in cerebral imagery have led to a better understanding of neurovisual deficits, such as cortical blindness. It thus becomes possible now to propose an earlier diagnosis of cortical blindness as well as new perspectives for rehabilitation in children as well as in adults. On the other hand, studying complex neurovisual deficits, such as cortical blindness is a way to infer normal functioning of the visual system. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  16. Non-concomitant cortical structural and functional alterations in sensorimotor areas following incomplete spinal cord injury.

    Science.gov (United States)

    Pan, Yu; Dou, Wei-Bei; Wang, Yue-Heng; Luo, Hui-Wen; Ge, Yun-Xiang; Yan, Shu-Yu; Xu, Quan; Tu, Yuan-Yuan; Xiao, Yan-Qing; Wu, Qiong; Zheng, Zhuo-Zhao; Zhao, Hong-Liang

    2017-12-01

    Brain plasticity, including anatomical changes and functional reorganization, is the physiological basis of functional recovery after spinal cord injury (SCI). The correlation between brain anatomical changes and functional reorganization after SCI is unclear. This study aimed to explore whether alterations of cortical structure and network function are concomitant in sensorimotor areas after incomplete SCI. Eighteen patients with incomplete SCI (mean age 40.94 ± 14.10 years old; male:female, 7:11) and 18 healthy subjects (37.33 ± 11.79 years old; male:female, 7:11) were studied by resting state functional magnetic resonance imaging. Gray matter volume (GMV) and functional connectivity were used to evaluate cortical structure and network function, respectively. There was no significant alteration of GMV in sensorimotor areas in patients with incomplete SCI compared with healthy subjects. Intra-hemispheric functional connectivity between left primary somatosensory cortex (BA1) and left primary motor cortex (BA4), and left BA1 and left somatosensory association cortex (BA5) was decreased, as well as inter-hemispheric functional connectivity between left BA1 and right BA4, left BA1 and right BA5, and left BA4 and right BA5 in patients with SCI. Functional connectivity between both BA4 areas was also decreased. The decreased functional connectivity between the left BA1 and the right BA4 positively correlated with American Spinal Injury Association sensory score in SCI patients. The results indicate that alterations of cortical anatomical structure and network functional connectivity in sensorimotor areas were non-concomitant in patients with incomplete SCI, indicating the network functional changes in sensorimotor areas may not be dependent on anatomic structure. The strength of functional connectivity within sensorimotor areas could serve as a potential imaging biomarker for assessment and prediction of sensory function in patients with incomplete SCI. This trial

  17. Research on acupuncture points and cortical functional activation position in cats by infrared imaging detection

    Science.gov (United States)

    Chen, Shuwang; Sha, Zhanyou; Wang, Shuhai; Wen, Huanming

    2007-12-01

    The research of the brain cognition is mainly to find out the activation position in brain according to the stimulation at present in the world. The research regards the animals as the experimental objects and explores the stimulation response on the cerebral cortex of acupuncture. It provides a new method, which can detect the activation position on the creatural cerebral cortex directly by middle-far infrared imaging. According to the theory of local temperature situation, the difference of cortical temperature maybe associate with the excitement of cortical nerve cells, the metabolism of local tissue and the local hemal circulation. Direct naked detection of temperature variety on cerebral cortex is applied by middle and far infrared imaging technology. So the activation position is ascertained. The effect of stimulation response is superior to other indirect methods. After removing the skulls on the head, full of cerebral cortex of a cat are exposed. By observing the infrared images and measuring the temperatures of the visual cerebral cortex during the process of acupuncturing, the points are used to judge the activation position. The variety in the cortical functional sections is corresponding to the result of the acupuncture points in terms of infrared images and temperatures. According to experimental results, we know that the variety of a cortical functional section is corresponding to a special acupuncture point exactly.

  18. FURTHER WORK ON THE SHAPING OF CORTICAL DEVELOPMENT AND FUNCTION BY SYNCHRONY AND METABOLIC COMPETITION

    Directory of Open Access Journals (Sweden)

    James Joseph Wright

    2016-12-01

    Full Text Available This paper furthers our attempts to resolve two major controversies – whether gamma synchrony plays a role in cognition, and whether cortical columns are functionally important. We have previously argued that the configuration of cortical cells that emerges in development is that which maximizes the magnitude of synchronous oscillation and minimizes metabolic cost. Here we analyze the separate effects in development of minimization of axonal lengths, and of early Hebbian learning and selective distribution of resources to growing synapses, by showing in simulations that these effects are partially antagonistic, but their interaction during development produces accurate anatomical and functional properties for both columnar and non-columnar cortex. The resulting embryonic anatomical order can provide a cortex-wide scaffold for postnatal learning that is dimensionally consistent with the representation of moving sensory objects, and, as learning progressively overwrites the embryonic order, further associations also occur in a dimensionally consistent framework. The role ascribed to cortical synchrony does not demand specific frequency, amplitude or phase variation of pulses to mediate feature linking. Instead, the concerted interactions of pulse synchrony with short-term synaptic dynamics and synaptic resource competition can further explain cortical information processing in analogy to Hopfield networks and quantum computation.

  19. Renal functional outcomes after surgery for renal cortical tumors

    Directory of Open Access Journals (Sweden)

    Danny Lascano

    2015-03-01

    Full Text Available Historically, radical nephrectomy represented the gold standard for the treatment of small (≤ 4cm as well as larger renal masses.  Recently, for small renal masses, the risk of ensuing chronic kidney disease and end stage renal disease has largely favored nephron-sparing surgical techniques, mainly partial nephrectomy. In this review, we surveyed the literature on renal functional outcomes after partial nephrectomy for renal tumors. The largest randomized control trial comparing radical and partial nephrectomy failed to show a survival benefit for partial nephrectomy. With regards to overall survival, surgically induced chronic kidney disease (GFR < 60 ml/min/ 1.73m2 caused by nephrectomy might not be as deleterious as medically induced chronic kidney disease. In evaluating patients who underwent donor nephrectomy, transplant literature further validates that surgically induced reductions in GFR may not affect patient survival, unlike medically induced GFR declines.  Yet, because patients who present with a renal mass tend to be elderly with multiple comorbidities, many develop a mixed picture of medically, and surgically-induced renal disease after extirpative renal surgery.  In this population, we believe that nephron sparing surgery optimizes oncological control while protecting renal function

  20. Functional Specialization of Seven Mouse Visual Cortical Areas

    Science.gov (United States)

    Marshel, James H.; Garrett, Marina E.; Nauhaus, Ian; Callaway, Edward M.

    2011-01-01

    SUMMARY To establish the mouse as a genetically-tractable model for high-order visual processing, we characterized fine-scale retinotopic organization of visual cortex, and determined functional specialization of layer 2/3 neuronal populations in seven retinotopically-identified areas. Each area contains a distinct visuotopic representation and encodes a unique combination of spatiotemporal features. Areas LM, AL, RL, and AM prefer up to three times faster temporal frequencies and significantly lower spatial frequencies than V1, while V1 and PM prefer high spatial and low temporal frequencies. LI prefers both high spatial and temporal frequencies. All extrastriate areas except LI increase orientation selectivity compared to V1, and three areas are significantly more direction selective (AL, RL, AM). Specific combinations of spatiotemporal representations further distinguish areas. These results reveal that mouse higher visual areas are functionally distinct, and separate groups of areas may be specialized for motion-related versus pattern-related computations perhaps forming pathways analogous to dorsal and ventral streams in other species. PMID:22196338

  1. Excitability of motor cortices as a function of emotional sounds.

    Directory of Open Access Journals (Sweden)

    Naeem Komeilipoor

    Full Text Available We used transcranial magnetic stimulation (TMS to clarify how non-verbal emotionally-characterized sounds modulate the excitability of the corticospinal motor tract (CST. While subjects were listening to sounds (monaurally and binaurally, single TMS pulses were delivered to either left or right primary motor cortex (M1, and electromyographic activities were recorded from the contralateral abductor pollicis brevis muscle. We found a significant increase in CST excitability in response to unpleasant as compared to neutral sounds. The increased excitability was lateralized as a function of stimulus valence: Unpleasant stimuli resulted in a significantly higher facilitation of motor potentials evoked in the left hemisphere, while pleasant stimuli yielded a greater CST excitability in the right one. Furthermore, TMS induced higher motor evoked potentials when listening to unpleasant sounds with the left than with the right ear. Taken together, our findings provide compelling evidence for an asymmetric modulation of CST excitability as a function of emotional sounds along with ear laterality.

  2. Functional role for cortical-striatal circuitry in modulating alcohol self-administration.

    Science.gov (United States)

    Jaramillo, Anel A; Randall, Patrick A; Stewart, Spencer; Fortino, Brayden; Van Voorhies, Kalynn; Besheer, Joyce

    2018-03-01

    The cortical-striatal brain circuitry is heavily implicated in drug-use. As such, the present study investigated the functional role of cortical-striatal circuitry in modulating alcohol self-administration. Given that a functional role for the nucleus accumbens core (AcbC) in modulating alcohol-reinforced responding has been established, we sought to test the role of cortical brain regions with afferent projections to the AcbC: the medial prefrontal cortex (mPFC) and the insular cortex (IC). Long-Evans rats were trained to self-administer alcohol (15% alcohol (v/v)+2% sucrose (w/v)) during 30 min sessions. To test the functional role of the mPFC or IC, we utilized a chemogenetic technique (hM4D i -Designer Receptors Activation by Designer Drugs) to silence neuronal activity prior to an alcohol self-administration session. Additionally, we chemogenetically silenced mPFC→AcbC or IC→AcbC projections, to investigate the role of cortical-striatal circuitry in modulating alcohol self-administration. Chemogenetically silencing the mPFC decreased alcohol self-administration, while silencing the IC increased alcohol self-administration, an effect absent in mCherry-Controls. Interestingly, silencing mPFC→AcbC projections had no effect on alcohol self-administration. In contrast, silencing IC→AcbC projections decreased alcohol self-administration, in a reinforcer-specific manner as there was no effect in rats trained to self-administer sucrose (0.8%, w/v). Additionally, no change in self-administration was observed in the mCherry-Controls. Together these data demonstrate the complex role of the cortical-striatal circuitry while implicating a role for the insula-striatal circuit in modulating ongoing alcohol self-administration. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Psychophysiology and Imaging of Visual Cortical Functions in the Blind: A Review

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    Stephanie L. Simon-Dack

    2008-01-01

    Full Text Available Imaging, transcranial magnetic stimulation, and psychophysiological recordings of the congenitally blind have confirmed functional activation of the visual cortex but have not extensively explained the functional significance of these activation patterns in detail. This review systematically examines research on the role of the visual cortex in processing spatial and non-visual information, highlighting research on individuals with early and late onset blindness. Here, we concentrate on the methods utilized in studying visual cortical activation in early blind participants, including positron emissions tomography (PET, functional magnetic resonance imaging (fMRI, transcranial magnetic stimulation (TMS, and electrophysiological data, specifically event-related potentials (ERPs. This paper summarizes and discusses findings of these studies. We hypothesize how mechanisms of cortical plasticity are expressed in congenitally in comparison to adventitiously blind and short-term visually deprived sighted participants and discuss potential approaches for further investigation of these mechanisms in future research.

  4. Increased Executive Functioning, Attention, and Cortical Thickness in White-Collar Criminals

    Science.gov (United States)

    Raine, Adrian; Laufer, William S.; Yang, Yaling; Narr, Katherine L.; Thompson, Paul; Toga, Arthur W.

    2011-01-01

    Very little is known on white collar crime and how it differs to other forms of offending. This study tests the hypothesis that white collar criminals have better executive functioning, enhanced information processing, and structural brain superiorities compared to offender controls. Using a case-control design, executive functioning, orienting, and cortical thickness was assessed in 21 white collar criminals matched with 21 controls on age, gender, ethnicity, and general level of criminal offending. White collar criminals had significantly better executive functioning, increased electrodermal orienting, increased arousal, and increased cortical gray matter thickness in the ventromedial prefrontal cortex, inferior frontal gyrus, somatosensory cortex, and the temporal-parietal junction compared to controls. Results, while initial, constitute the first findings on neurobiological characteristics of white-collar criminals It is hypothesized that white collar criminals have information-processing and brain superiorities that give them an advantage in perpetrating criminal offenses in occupational settings. PMID:22002326

  5. The renal cortical interstitium: morphological and functional aspects.

    Science.gov (United States)

    Kaissling, Brigitte; Le Hir, Michel

    2008-08-01

    The renal interstitial compartment, situated between basement membranes of epithelia and vessels, contains two contiguous cellular networks. One network is formed by interstitial fibroblasts, the second one by dendritic cells. Both are in intimate contact with each other. Fibroblasts are interconnected by junctions and connected to basement membranes of vessels and tubules by focal adhesions. Fibroblasts constitute the "skeleton" of the kidney. In the renal cortex, fibroblasts produce erythropoietin and are distinguished from other interstitial cells by their prominent F-actin cytoskeleton, abundance of rough endoplasmic reticulum, and by ecto-5'-nucleotidase expression in their plasma membrane. The resident dendritic cells belong to the mononuclear phagocyte system and fulfil a sentinel function. They are characterized by their expression of MHC class II and CD11c. The central situation of fibroblasts suggests that signals from tubules, vessels, and inflammatory cells converge in fibroblasts and elicit an integrated response. Following tubular damage and inflammatory signals fibroblasts proliferate, change to the myofibroblast phenotype and increase their collagen production, potentially resulting in renal fibrosis. The acquisition of a profibrotic phenotype by fibroblasts in renal diseases is generally considered a main causal event in the progression of chronic renal failure. However, it might also be seen as a repair process.

  6. Gustatory Imagery Reveals Functional Connectivity from the Prefrontal to Insular Cortices Traced with Magnetoencephalography

    OpenAIRE

    Masayuki Kobayashi; Tetsuya Sasabe; Yoshihito Shigihara; Masaaki Tanaka; Yasuyoshi Watanabe

    2011-01-01

    Our experience and prejudice concerning food play an important role in modulating gustatory information processing; gustatory memory stored in the central nervous system influences gustatory information arising from the peripheral nervous system. We have elucidated the mechanism of the 'top-down" modulation of taste perception in humans using functional magnetic resonance imaging (fMRI) and demonstrated that gustatory imagery is mediated by the prefrontal (PFC) and insular cortices (IC). Howe...

  7. Asymmetric function of theta and gamma activity in syllable processing: an intra-cortical study

    Directory of Open Access Journals (Sweden)

    Benjamin eMorillon

    2012-07-01

    Full Text Available Low-gamma (25-45 Hz and theta (4-8 Hz oscillations are proposed to underpin the integration of phonemic and syllabic information, respectively. How these two scales of analysis split functions across hemispheres is unclear. We analyzed cortical responses from an epileptic patient with a rare bilateral electrode implantation (stereotactic EEG in primary (A1/BA41 and A2/BA42 and association auditory cortices (BA22. Using time-frequency analyses, we confirmed the dominance of a 5-6 Hz theta activity in right and of a low-gamma (25-45 Hz activity in left primary auditory cortices (A1/A2, during both resting state and syllable processing. We further detected high-theta (7-8 Hz resting activity in left primary, but also associative auditory regions. In left BA22, its phase correlated with high-gamma induced power. Such a hierarchical relationship across theta and gamma frequency bands (theta/gamma phase-amplitude coupling could index the process by which the neural code shifts from stimulus feature- to phonological- encoding, and is associated with the transition from evoked to induced power responses. These data suggest that theta and gamma activity in right and left auditory cortices bear different functions. They support a scheme where slow parsing of the acoustic information dominates in right-hemisphere at a syllabic (5-6 Hz rate, and left auditory cortex exhibits a more complex cascade of oscillations, reflecting the possible extraction of transient acoustic cues at a fast (~25-45 Hz rate, subsequently integrated at a slower, e.g. syllabic one. Slow oscillations could functionally participate to speech processing by structuring gamma activity in left BA22, where abstract percepts emerge.

  8. Functionally aberrant electrophysiological cortical connectivities in first episode medication-naive schizophrenics from three psychiatry centers

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    Dietrich eLehmann‡

    2014-08-01

    Full Text Available Functional dissociation between brain processes is widely hypothesized to account for aberrations of thought and emotions in schizophrenic patients. The typically small groups of analyzed schizophrenic patients yielded different neurophysiological findings, probably because small patient groups are likely to comprise different schizophrenia subtypes. We analyzed multichannel eyes-closed resting EEG from three small groups of acutely ill, first episode productive schizophrenic patients before start of medication (from three centers: Bern N=9; Osaka N=9; Berlin N=12 and their controls. Low resolution brain electromagnetic tomography (LORETA was used to compute intracortical source model-based lagged functional connectivity not biased by volume conduction effects between 19 cortical regions of interest (ROIs. The connectivities were compared between controls and patients of each group. Conjunction analysis determined six aberrant cortical functional connectivities that were the same in the three patient groups. Four of these six concerned the facilitating EEG alpha 1 frequency activity; they were decreased in the patients. Another two of these six connectivities concerned the inhibiting EEG delta frequency activity; they were increased in the patients. The principal orientation of the six aberrant cortical functional connectivities was sagittal; five of them involved both hemispheres. In sum, activity in the posterior brain areas of preprocessing functions and the anterior brain areas of evaluation and behavior control functions were compromised by either decreased coupled activation or increased coupled inhibition, common across schizophrenia subtypes in the three patient groups. These results of the analyzed three independent groups of schizophrenics support the concept of functional dissociation.

  9. Modulating epigenetic mechanisms: the diverse functions of Ski during cortical development.

    Science.gov (United States)

    Baranek, Constanze; Atanasoski, Suzana

    2012-07-01

    In the developing forebrain, neural stem and progenitor cells generate a large variety of neurons with specific functions in the mature cortex. A central issue is to understand the roles of transcriptional networks and regulatory pathways that control these complex developmental processes. The proto-oncogene Ski is a transcriptional regulator linked to the human 1p36 deletion syndrome, which involves a set of phenotypes including nervous system defects. Ski shows a dynamic expression pattern during cortical development and, accordingly, the phenotype of Ski-deficient cortices is complex, involving altered cell cycle characteristics of neural progenitors, disturbed timing of neurogenesis and mis-specification of projection neurons. Ski is likely to play a role in various pathways by virtue of its ability to interact with a range of signaling molecules, thereby modulating transcriptional activity of corresponding target genes. Ski regulates proliferation and differentiation of various cell types, and more recent data from my laboratory demonstrates that Ski is also involved in the specification of cortical projection neurons. This Point-of-View elucidates the role of Ski as an essential linker between sequence-specific transcription factors and non-DNA binding cofactors with chromatin modifying activities. In particular, it puts forward the hypothesis that the diverse functions of Ski as a co-repressor might be related to its association with distinct HDAC-complexes.

  10. Conservation of sequence and function in fertilization of the cortical granule serine protease in echinoderms.

    Science.gov (United States)

    Oulhen, Nathalie; Xu, Dongdong; Wessel, Gary M

    2014-08-01

    Conservation of the cortical granule serine protease during fertilization in echinoderms was tested both functionally in sea stars, and computationally throughout the echinoderm phylum. We find that the inhibitor of serine protease (soybean trypsin inhibitor) effectively blocks proper transition of the sea star fertilization envelope into a protective sperm repellent, whereas inhibitors of the other main types of proteases had no effect. Scanning the transcriptomes of 15 different echinoderm ovaries revealed sequences of high conservation to the originally identified sea urchin cortical serine protease, CGSP1. These conserved sequences contained the catalytic triad necessary for enzymatic activity, and the tandemly repeated LDLr-like repeats. We conclude that the protease involved in the slow block to polyspermy is an essential and conserved element of fertilization in echinoderms, and may provide an important reagent for identification and testing of the cell surface proteins in eggs necessary for sperm binding. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. Visual function and cortical organization in carriers of blue cone monochromacy.

    Directory of Open Access Journals (Sweden)

    Ethan A Rossi

    Full Text Available Carriers of blue cone monochromacy have fewer cone photoreceptors than normal. Here we examine how this disruption at the level of the retina affects visual function and cortical organization in these individuals. Visual resolution and contrast sensitivity was measured at the preferred retinal locus of fixation and visual resolution was tested at two eccentric locations (2.5° and 8° with spectacle correction only. Adaptive optics corrected resolution acuity and cone spacing were simultaneously measured at several locations within the central fovea with adaptive optics scanning laser ophthalmoscopy (AOSLO. Fixation stability was assessed by extracting eye motion data from AOSLO videos. Retinotopic mapping using fMRI was carried out to estimate the area of early cortical regions, including that of the foveal confluence. Without adaptive optics correction, BCM carriers appeared to have normal visual function, with normal contrast sensitivity and visual resolution, but with AO-correction, visual resolution was significantly worse than normal. This resolution deficit is not explained by cone loss alone and is suggestive of an associated loss of retinal ganglion cells. However, despite evidence suggesting a reduction in the number of retinal ganglion cells, retinotopic mapping showed no reduction in the cortical area of the foveal confluence. These results suggest that ganglion cell density may not govern the foveal overrepresentation in the cortex. We propose that it is not the number of afferents, but rather the content of the information relayed to the cortex from the retina across the visual field that governs cortical magnification, as under normal viewing conditions this information is similar in both BCM carriers and normal controls.

  12. A cortical sparse distributed coding model linking mini- and macrocolumn-scale functionality

    Directory of Open Access Journals (Sweden)

    Gerard J Rinkus

    2010-06-01

    Full Text Available No generic function for the minicolumn—i.e., one that would apply equally well to all cortical areas and species—has yet been proposed. I propose that the minicolumn does have a generic functionality, which only becomes clear when seen in the context of the function of the higher-level, subsuming unit, the macrocolumn. I propose that: a a macrocolumn’s function is to store sparse distributed representations of its inputs and to be a recognizer of those inputs; and b the generic function of the minicolumn is to enforce macrocolumnar code sparseness. The minicolumn, defined here as a physically localized pool of ~20 L2/3 pyramidals, does this by acting as a winner-take-all (WTA competitive module, implying that macrocolumnar codes consist of ~70 active L2/3 cells, assuming ~70 minicolumns per macrocolumn. I describe an algorithm for activating these codes during both learning and retrievals, which causes more similar inputs to map to more highly intersecting codes, a property which yields ultra-fast (immediate, first-shot storage and retrieval. The algorithm achieves this by adding an amount of randomness (noise into the code selection process, which is inversely proportional to an input’s familiarity. I propose a possible mapping of the algorithm onto cortical circuitry, and adduce evidence for a neuromodulatory implementation of this familiarity-contingent noise mechanism. The model is distinguished from other recent columnar cortical circuit models in proposing a generic minicolumnar function in which a group of cells within the minicolumn, the L2/3 pyramidals, compete (WTA to be part of the macrocolumnar code.

  13. Abnormal reorganization of functional cortical small-world networks in focal hand dystonia.

    Directory of Open Access Journals (Sweden)

    Seung-Hyun Jin

    Full Text Available We investigated the large-scale functional cortical connectivity network in focal hand dystonia (FHD patients using graph theoretic measures to assess efficiency. High-resolution EEGs were recorded in 15 FHD patients and 15 healthy volunteers at rest and during a simple sequential finger tapping task. Mutual information (MI values of wavelet coefficients were estimated to create an association matrix between EEG electrodes, and to produce a series of adjacency matrices or graphs, G, by thresholding with network cost. Efficiency measures of small-world networks were assessed. As a result, we found that FHD patients have economical small-world properties in their brain functional networks in the alpha and beta bands. During a motor task, in the beta band network, FHD patients have decreased efficiency of small-world networks, whereas healthy volunteers increase efficiency. Reduced efficient beta band network in FHD patients during the task was consistently observed in global efficiency, cost-efficiency, and maximum cost-efficiency. This suggests that the beta band functional cortical network of FHD patients is reorganized even during a task that does not induce dystonic symptoms, representing a loss of long-range communication and abnormal functional integration in large-scale brain functional cortical networks. Moreover, negative correlations between efficiency measures and duration of disease were found, indicating that the longer duration of disease, the less efficient the beta band network in FHD patients. In regional efficiency analysis, FHD patients at rest have high regional efficiency at supplementary motor cortex (SMA compared with healthy volunteers; however, it is diminished during the motor task, possibly reflecting abnormal inhibition in FHD patients. The present study provides the first evidence with graph theory for abnormal reconfiguration of brain functional networks in FHD during motor task.

  14. Transcranial Magnetic Stimulation: A Neuroscientific Probe of Cortical Function in Schizophrenia

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    McClintock, Shawn M.; Freitas, Catarina; Oberman, Lindsay; Lisanby, Sarah H.; Pascual-Leone, Alvaro

    2012-01-01

    Transcranial magnetic stimulation (TMS) is a neuropsychiatric tool that can serve as a useful method to better understand the neurobiology of cognitive function, behavior, and emotional processing. The purpose of this paper is to examine the utility of TMS as a means of measuring neocortical function in neuropsychiatric disorders in general, and schizophrenia in particular, for the Cognitive Neuroscience Treatment Research to Improve Cognition in Schizophrenia (CNTRICS) initiative. When incorporating TMS paradigms in research studies, methodological considerations include technical aspects of TMS, cohort selection and confounding factors, and subject safety. Available evidence suggests benefits of TMS alone or in combination with neurophysiologic and neuroimaging methods, including positron emission tomography (PET), single photon emission computed tomography (SPECT), magnetic resonance imaging (MRI), functional MRI (fMRI), functional near infrared spectroscopy (fNIRS), magnetoencephalography (MEG), and electroencephalography (EEG), to explore neocortical function. With the multiple TMS techniques including single-pulse, paired-pulse, paired associative stimulation, and repetitive TMS and theta burst stimulation, combined with neurophysiologic and neuroimaging methods, there exists a plethora of TMS experimental paradigms to modulate different neocortical physiologic processes. Specifically, TMS can measure cortical excitability, intracortical inhibitory and excitatory mechanisms, and local and network cortical plasticity. Coupled with functional and electrophysiological modalities, TMS can provide insight into the mechanisms underlying healthy neurodevelopment and aging, as well as neuropsychiatric pathology. Thus, TMS could be a useful tool in the CNTRICS armamentarium of biomarker methods. Future investigations are warranted to optimize TMS methodologies for this purpose. PMID:21571254

  15. A survey on stimuli for visual cortical function assessment in infants.

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    Daneshvarfard, Farveh; Maarefi, Nasrin; Abrishami Moghaddam, Hamid; Wallois, Fabrice

    2018-01-01

    Visual processing, as a significant and complex functionality of the human brain, changes during the life span with the most developmental changes in the infancy. Different types of visual stimuli are needed for evaluating different functionalities of the infants' visual system. Selecting appropriate visual stimuli is an important issue in evaluating visual cortical functions in infants. Properties of stimulation influence responses of visual system and must be adjusted according to the age and specific function which is going to be investigated. In this review, the most commonly used stimuli to elicit visual evoked potentials (VEPs) are evaluated and characteristics of VEPs extracted by these stimulations are studied. Furthermore, various studies investigating different functionalities such as selectivity for orientation and directional motion are presented. Valuable results regarding emerging and maturation times of different functions and normative data for clinical diagnosis are provided by these studies. Copyright © 2017 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

  16. Cortical reorganization during PASAT task in MS patients with preserved working memory functions.

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    Forn, C; Barros-Loscertales, A; Escudero, J; Belloch, V; Campos, S; Parcet, M A; Avila, C

    2006-06-01

    Cortical reorganization in multiple sclerosis (MS) is defined as a compensatory mechanism which requires MS patients to overactivate specific brain areas in order to perform the task as controls. To investigate this process with the Paced Auditory Serial Addition Test (PASAT) task, we selected 15 MS patients who performed the PASAT task within-normal limits and 10 healthy controls. Once selected, we used functional magnetic resonance imaging (fMRI) to investigate brain areas involved in PASAT performance in both groups. Results showed that the task activated the left frontal (BA6 and 9) and parietal cortex (BA7 and 40) in both groups, but MS patients showed a stronger activation in the left prefrontal cortex (BA9, 44 and 45) when compared with controls. These results confirmed those obtained post hoc by Audoin et al. [Audoin, B., Ibarrola, D., Ranjeva, J.P., Confort-Gouny, S., Malikova, I., Ali-Chérif, A.M., Pelletier, J., Cozzone, P., et al., 2003. Compensatory cortical activation observed by fMRI during cognitive task at the earliest stage of MS. Hum. Brain Mapp. 20, 51-58], and we interpreted this as showing true cortical reorganization.

  17. Regional cortical thinning and cerebrospinal biomarkers predict worsening daily functioning across the Alzheimer disease spectrum

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    Marshall, Gad A.; Lorius, Natacha; Locascio, Joseph J.; Hyman, Bradley T.; Rentz, Dorene M.; Johnson, Keith A.; Sperling, Reisa A.

    2014-01-01

    Background Impairment in instrumental activities of daily living (IADL) heralds the transition from mild cognitive impairment (MCI) to dementia and is a major source of burden for both the patient and caregiver. Objective To investigate the relationship between IADL and regional cortical thinning and cerebrospinal fluid (CSF) Alzheimer disease (AD) biomarkers cross-sectionally and longitudinally in clinically normal (CN) elderly, MCI, and mild AD dementia subjects. Methods Two hundred and twenty nine CN, 395 MCI, and 188 AD dementia subjects participating in the Alzheimer's Disease Neuroimaging Initiative underwent baseline magnetic resonance imaging, baseline lumbar puncture, and clinical assessments, including the Functional Activities Questionnaire used to measure IADL, every 6 to 12 months up to 3 years. General linear regression and mixed effects models were employed. Results IADL impairment was associated with the interactions between lower inferior temporal cortical thickness and diagnosis (p<0.0001), greater lateral occipital cortical thickness and diagnosis (p<0.0001), and greater amyloid-beta 1-42 (Aβ1-42) and diagnosis (p=0.0002) at baseline (driven by AD dementia). Lower baseline supramarginal (p=0.02) and inferior temporal (p=0.05) cortical thickness, lower Aβ1-42 (p<0.0001), and greater total tau (t-tau) (p=0.02) were associated with greater rate of IADL impairment over time. Conclusions Temporal atrophy is associated with IADL impairment in mild AD dementia at baseline, while baseline parietal and temporal atrophy, lower CSF Aβ1-42, and greater t-tau predict worsening IADL impairment over time across the AD spectrum. These results emphasize the importance of assessing IADL at the stage of MCI and even at the transition from CN to MCI. PMID:24685624

  18. Differentiation of Attention-Related Problems in Childhood Absence Epilepsy

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    Vega, Clemente; Vestal, Matthew; DeSalvo, Matthew; Berman, Rachel; Chung, MiHae; Blumenfeld, Hal; Spann, Marisa N.

    2010-01-01

    The current study examined the specific types of attention-related problems CAE children experience and the role of disease factors on the development of attention-related problems. Thirty-eight subjects with CAE and 46 healthy controls, ages 6 to 16 participated in the study. The Behavior Assessment System for Children (BASC) was completed by parents, and the Attention Problems and Hyperactivity subscales were used to characterize CAE children’s problems. Item analysis within the subscales revealed that CAE children demonstrated higher rates of hyperactive (overactivity and fidgetiness) and inattentive (forgetfulness and distractibility) problems, and required more supervision. Within CAE analyses revealed that those who were actively having seizures were more impatient and those with a longer duration of illness were less proficient in completing homework. Children with CAE are at risk for certain inattentive and hyperactive problems, which can differ depending on duration of illness and active seizure status. PMID:20674507

  19. Cortical and subcortical functional neuroanatomy for low-grade glioma surgery.

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    Chenin, L; Lefranc, M; Velut, S; Foulon, P; Havet, E; Peltier, J

    2017-06-01

    Knowledge of the encephalon anatomy is crucial for neurosurgical practice, especially the main cortical functional structures and their connections. General organisation of the encephalon is presented with frontal, parietal, occipital, temporal, limbic and insular lobes and their Brodmann correspondence. Secondly, subcortical anatomy will be presented with main white matter fasciculi in three separated categories: association, commissural and projection fibers. Main association fibers are inferior occipitofrontal fasciculus, superior longitudinal fasciculus, arcuate fasciculus, inferior longitudinal fasciculus, uncinate fasciculus, and cingulum. Commissural fibers include anterior commissure, corpus callosum and fornix. Projection fibers are internal capsule and optic radiations. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  20. Functions of gamma-band synchronization in cognition: from single circuits to functional diversity across cortical and subcortical systems.

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    Bosman, Conrado A; Lansink, Carien S; Pennartz, Cyriel M A

    2014-06-01

    Gamma-band activity (30-90 Hz) and the synchronization of neural activity in the gamma-frequency range have been observed in different cortical and subcortical structures and have been associated with different cognitive functions. However, it is still unknown whether gamma-band synchronization subserves a single universal function or a diversity of functions across the full spectrum of cognitive processes. Here, we address this question reviewing the mechanisms of gamma-band oscillation generation and the functions associated with gamma-band activity across several cortical and subcortical structures. Additionally, we raise a plausible explanation of why gamma rhythms are found so ubiquitously across brain structures. Gamma band activity originates from the interplay between inhibition and excitation. We stress that gamma oscillations, associated with this interplay, originate from basic functional motifs that conferred advantages for low-level system processing and multiple cognitive functions throughout evolution. We illustrate the multifunctionality of gamma-band activity by considering its role in neural systems for perception, selective attention, memory, motivation and behavioral control. We conclude that gamma-band oscillations support multiple cognitive processes, rather than a single one, which, however, can be traced back to a limited set of circuit motifs which are found universally across species and brain structures. © 2014 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  1. Inferring deep-brain activity from cortical activity using functional near-infrared spectroscopy

    Science.gov (United States)

    Liu, Ning; Cui, Xu; Bryant, Daniel M.; Glover, Gary H.; Reiss, Allan L.

    2015-01-01

    Functional near-infrared spectroscopy (fNIRS) is an increasingly popular technology for studying brain function because it is non-invasive, non-irradiating and relatively inexpensive. Further, fNIRS potentially allows measurement of hemodynamic activity with high temporal resolution (milliseconds) and in naturalistic settings. However, in comparison with other imaging modalities, namely fMRI, fNIRS has a significant drawback: limited sensitivity to hemodynamic changes in deep-brain regions. To overcome this limitation, we developed a computational method to infer deep-brain activity using fNIRS measurements of cortical activity. Using simultaneous fNIRS and fMRI, we measured brain activity in 17 participants as they completed three cognitive tasks. A support vector regression (SVR) learning algorithm was used to predict activity in twelve deep-brain regions using information from surface fNIRS measurements. We compared these predictions against actual fMRI-measured activity using Pearson’s correlation to quantify prediction performance. To provide a benchmark for comparison, we also used fMRI measurements of cortical activity to infer deep-brain activity. When using fMRI-measured activity from the entire cortex, we were able to predict deep-brain activity in the fusiform cortex with an average correlation coefficient of 0.80 and in all deep-brain regions with an average correlation coefficient of 0.67. The top 15% of predictions using fNIRS signal achieved an accuracy of 0.7. To our knowledge, this study is the first to investigate the feasibility of using cortical activity to infer deep-brain activity. This new method has the potential to extend fNIRS applications in cognitive and clinical neuroscience research. PMID:25798327

  2. The quality of cortical network function recovery depends on localization and degree of axonal demyelination.

    Science.gov (United States)

    Cerina, Manuela; Narayanan, Venu; Göbel, Kerstin; Bittner, Stefan; Ruck, Tobias; Meuth, Patrick; Herrmann, Alexander M; Stangel, Martin; Gudi, Viktoria; Skripuletz, Thomas; Daldrup, Thiemo; Wiendl, Heinz; Seidenbecher, Thomas; Ehling, Petra; Kleinschnitz, Christoph; Pape, Hans-Christian; Budde, Thomas; Meuth, Sven G

    2017-01-01

    Myelin loss is a severe pathological hallmark common to a number of neurodegenerative diseases, including multiple sclerosis (MS). Demyelination in the central nervous system appears in the form of lesions affecting both white and gray matter structures. The functional consequences of demyelination on neuronal network and brain function are not well understood. Current therapeutic strategies for ameliorating the course of such diseases usually focus on promoting remyelination, but the effectiveness of these approaches strongly depends on the timing in relation to the disease state. In this study, we sought to characterize the time course of sensory and behavioral alterations induced by de- and remyelination to establish a rational for the use of remyelination strategies. By taking advantage of animal models of general and focal demyelination, we tested the consequences of myelin loss on the functionality of the auditory thalamocortical system: a well-studied neuronal network consisting of both white and gray matter regions. We found that general demyelination was associated with a permanent loss of the tonotopic cortical organization in vivo, and the inability to induce tone-frequency-dependent conditioned behaviors, a status persisting after remyelination. Targeted, focal lysolecithin-induced lesions in the white matter fiber tract, but not in the gray matter regions of cortex, were fully reversible at the morphological, functional and behavioral level. These findings indicate that remyelination of white and gray matter lesions have a different functional regeneration potential, with the white matter being able to regain full functionality while cortical gray matter lesions suffer from permanently altered network function. Therefore therapeutic interventions aiming for remyelination have to consider both region- and time-dependent strategies. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  3. Functional MRI characteristics of a focal region of cortical malformation not associated with seizure onset.

    Science.gov (United States)

    Danckert, James; Mirsattari, Seyed M; Bihari, Frank; Danckert, Stacey; Allman, Ava-Ann; Janzen, Laura

    2007-06-01

    Neuroimaging studies have demonstrated that heterotopic tissue of patients with "double cortex" is activated during motor and somatosensory tasks. Activation in patients with malformations of cortical development (MCD) has been variable, likely due to the heterogeneity of the disorder. We examined clinical, electroencephalography (EEG), neuropsychological, and functional MRI findings in a patient with intractable epilepsy secondary to MCD in the left temporal cortex. Invasive EEG monitoring revealed that the dysplastic tissue was not involved in ictal onset of seizures. Functional MRI tests of motion and object processing, memory encoding, and language demonstrated no activation within dysplastic tissue. Hemispheric asymmetries in activation for motion and object processing were evident, favoring the right hemisphere--a pattern not evident in controls. These weaker activations in the patient were present in tissue proximal to the seizure focus. Thus, nonepileptogenic dysplastic tissue may not support cognitive functions, with abnormal processing evident in epileptogenic tissue.

  4. Light up ADHD: I. Cortical hemodynamic responses measured by functional Near Infrared Spectroscopy (fNIRS).

    Science.gov (United States)

    Mauri, Maddalena; Nobile, Maria; Bellina, Monica; Crippa, Alessandro; Brambilla, Paolo

    2017-11-21

    Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by deficits in cognitive and emotional self-control. Optical technique acquisitions, such as near infrared spectroscopy (NIRS), seem to be very promising during developmental ages, as they are non- invasive techniques and less influenced by body movements than other neuroimaging methods. Recently, these new techniques are being widely used to measure neural correlates underlying neuropsychological deficits in children with ADHD. In a short series of articles, we will review the results of functional NIRS (fNIRS) studies in children with ADHD. The present brief review will focus on the results of the fNIRS studies that investigate cortical activity during neuropsychological and/or emotional tasks. According to the reviewed studies, children and adolescents with ADHD show peculiar cortical activation both during neurological and emotional tasks, and the majority of the reviewed studies revealed lower prefrontal cortex activation in patients compared to typically developmental controls. a consistent interpretation of these results is limited by the substantial methodological heterogeneity including patients' medication status and washout period, explored cerebral regions, neuropsychological tasks, number of channels and sampling temporal resolutions. fNIRS seems to be a promising tool for investigating neural substrates of emotional dysregulation and executive function deficits in individuals with ADHD during developmental ages. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Coregistering functional near-infrared spectroscopy with underlying cortical areas in infants

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    Lloyd-Fox, Sarah; Richards, John E.; Blasi, Anna; Murphy, Declan G. M.; Elwell, Clare E.; Johnson, Mark H.

    2014-01-01

    Abstract. Functional near-infrared spectroscopy (fNIRS) is becoming a popular tool in developmental neuroscience for mapping functional localized brain responses. However, as it cannot provide information about underlying anatomy, researchers have begun to conduct spatial registration of fNIRS channels to cortical anatomy in adults. The current work investigated this issue with infants by coregistering fNIRS and magnetic resonance imaging (MRI) data from 55 individuals. Our findings suggest that fNIRS channels can be reliably registered with regions in the frontal and temporal cortex of infants from 4 to 7 months of age. Although some macro-anatomical regions are difficult to consistently define, others are more stable and fNIRS channels on an age-appropriate MRI template are often consistent with individual infant MRIs. We have generated a standardized scalp surface map of fNIRS channel locators to reliably locate cortical regions for fNIRS developmental researchers. This new map can be used to identify the inferior frontal gyrus, superior temporal sulcus (STS) region [which includes the superior and middle temporal gyri (MTG) nearest to the STS], and MTG and temporal-parietal regions in 4- to 7-month-old infants. Future work will model data for the whole head, taking into account the properties of light transport in tissue, and expanding to different ages across development. PMID:25558463

  6. Juxtasomal biocytin labeling to study the structure-function relationship of individual cortical neurons.

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    Narayanan, Rajeevan T; Mohan, Hemanth; Broersen, Robin; de Haan, Roel; Pieneman, Anton W; de Kock, Christiaan P J

    2014-02-25

    The cerebral cortex is characterized by multiple layers and many distinct cell-types that together as a network are responsible for many higher cognitive functions including decision making, sensory-guided behavior or memory. To understand how such intricate neuronal networks perform such tasks, a crucial step is to determine the function (or electrical activity) of individual cell types within the network, preferentially when the animal is performing a relevant cognitive task. Additionally, it is equally important to determine the anatomical structure of the network and the morphological architecture of the individual neurons to allow reverse engineering the cortical network. Technical breakthroughs available today allow recording cellular activity in awake, behaving animals with the valuable option of post hoc identifying the recorded neurons. Here, we demonstrate the juxtasomal biocytin labeling technique, which involves recording action potential spiking in the extracellular (or loose-patch) configuration using conventional patch pipettes. The juxtasomal recording configuration is relatively stable and applicable across behavioral conditions, including anesthetized, sedated, awake head-fixed, and even in the freely moving animal. Thus, this method allows linking cell-type specific action potential spiking during animal behavior to reconstruction of the individual neurons and ultimately, the entire cortical microcircuit. In this video manuscript, we show how individual neurons in the juxtasomal configuration can be labeled with biocytin in the urethane-anaesthetized rat for post hoc identification and morphological reconstruction.

  7. Language and motor function thresholds during pediatric extra-operative electrical cortical stimulation brain mapping.

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    Zea Vera, Alonso; Aungaroon, Gewalin; Horn, Paul S; Byars, Anna W; Greiner, Hansel M; Tenney, Jeffrey R; Arthur, Todd M; Crone, Nathan E; Holland, Katherine D; Mangano, Francesco T; Arya, Ravindra

    2017-10-01

    To examine current thresholds and their determinants for language and motor mapping with extra-operative electrical cortical stimulation (ECS). ECS electrocorticograph recordings were reviewed to determine functional thresholds. Predictors of functional thresholds were found with multivariable analyses. In 122 patients (age 11.9±5.4years), average minimum, frontal, and temporal language thresholds were 7.4 (± 3.0), 7.8 (± 3.0), and 7.4 (± 3.1) mA respectively. Average minimum, face, upper and lower extremity motor thresholds were 5.4 (± 2.8), 6.1 (± 2.8), 4.9 (± 2.3), and 5.3 (± 3.3) mA respectively. Functional and after-discharge (AD)/seizure thresholds were significantly related. Minimum, frontal, and temporal language thresholds were higher than AD thresholds at all ages. Minimum motor threshold was higher than minimum AD threshold up to 8.0years of age, face motor threshold was higher than frontal AD threshold up to 11.8years age, and lower subsequently. UE motor thresholds remained below frontal AD thresholds throughout the age range. Functional thresholds are frequently above AD thresholds in younger children. These findings raise concerns about safety and neurophysiologic validity of ECS mapping. Functional and AD/seizure thresholds relationships suggest individual differences in cortical excitability which cannot be explained by clinical variables. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

  8. Right frontal pole cortical thickness and executive functioning in children with traumatic brain injury: the impact on social problems.

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    Levan, Ashley; Black, Garrett; Mietchen, Jonathan; Baxter, Leslie; Brock Kirwan, C; Gale, Shawn D

    2016-12-01

    Cognitive and social outcomes may be negatively affected in children with a history of traumatic brain injury (TBI). We hypothesized that executive function would mediate the association between right frontal pole cortical thickness and problematic social behaviors. Child participants with a history of TBI were recruited from inpatient admissions for long-term follow-up (n = 23; average age = 12.8, average time post-injury =3.2 years). Three measures of executive function, the Trail Making Test, verbal fluency test, and the Conners' Continuous Performance Test-Second edition (CPT-II), were administered to each participant while caregivers completed the Childhood Behavior Checklist (CBCL). All participants underwent brain magnetic resonance imaging following cognitive testing. Regression analysis demonstrated right frontal pole cortical thickness significantly predicted social problems. Measures of executive functioning also significantly predicted social problems; however, the mediation model testing whether executive function mediated the relationship between cortical thickness and social problems was not statistically significant. Right frontal pole cortical thickness and omission errors on the CPT-II predicted Social Problems on the CBCL. Results did not indicate that the association between cortical thickness and social problems was mediated by executive function.

  9. [The amplitude principle of the structural-functional classification of cortical neurons].

    Science.gov (United States)

    Gasanov, U G

    1986-01-01

    Some literature and author's experimental data are presented on functional and morphological characteristics of nerve cells by their electrophysiological parameters. The proposition is substantiated that in multineuron discharges reflecting the activity of microgroups of neighbouring cells, the absolute size of impulses indicates the distance of cortical neurones from the tip of the electrode, while amplitudes correlation may characterize the size of the cell and some of its functional properties. Arguments for this proposition are: latencies of impulse responses to afferent and antidromic stimulations and amplitude changes of multineuronal activity during movement of the electrode through the cortex thickness in acute experiments. As the electrode (with the tip diameter of 50 mcm) approaches a microgroup of neurons, the amplitude of the recorded impulse discharges increases, while the relation of big spikes to small ones remains almost the same.

  10. Cortical substrates and functional correlates of auditory deviance processing deficits in schizophrenia

    Directory of Open Access Journals (Sweden)

    Anthony J. Rissling

    2014-01-01

    Full Text Available Although sensory processing abnormalities contribute to widespread cognitive and psychosocial impairments in schizophrenia (SZ patients, scalp-channel measures of averaged event-related potentials (ERPs mix contributions from distinct cortical source-area generators, diluting the functional relevance of channel-based ERP measures. SZ patients (n = 42 and non-psychiatric comparison subjects (n = 47 participated in a passive auditory duration oddball paradigm, eliciting a triphasic (Deviant−Standard tone ERP difference complex, here termed the auditory deviance response (ADR, comprised of a mid-frontal mismatch negativity (MMN, P3a positivity, and re-orienting negativity (RON peak sequence. To identify its cortical sources and to assess possible relationships between their response contributions and clinical SZ measures, we applied independent component analysis to the continuous 68-channel EEG data and clustered the resulting independent components (ICs across subjects on spectral, ERP, and topographic similarities. Six IC clusters centered in right superior temporal, right inferior frontal, ventral mid-cingulate, anterior cingulate, medial orbitofrontal, and dorsal mid-cingulate cortex each made triphasic response contributions. Although correlations between measures of SZ clinical, cognitive, and psychosocial functioning and standard (Fz scalp-channel ADR peak measures were weak or absent, for at least four IC clusters one or more significant correlations emerged. In particular, differences in MMN peak amplitude in the right superior temporal IC cluster accounted for 48% of the variance in SZ-subject performance on tasks necessary for real-world functioning and medial orbitofrontal cluster P3a amplitude accounted for 40%/54% of SZ-subject variance in positive/negative symptoms. Thus, source-resolved auditory deviance response measures including MMN may be highly sensitive to SZ clinical, cognitive, and functional characteristics.

  11. Language functional MRI and direct cortical stimulation in epilepsy preoperative planning.

    Science.gov (United States)

    Austermuehle, Alison; Cocjin, John; Reynolds, Richard; Agrawal, Shubhi; Sepeta, Leigh; Gaillard, William D; Zaghloul, Kareem A; Inati, Sara; Theodore, William H

    2017-04-01

    Presurgical language assessment can help minimize damage to eloquent cortex during resective epilepsy surgery. Two methods for presurgical language mapping are functional MRI (fMRI) and direct cortical stimulation (DCS) of implanted subdural electrodes. We compared fMRI results to DCS to help optimize noninvasive language localization and assess its validity. We studied 19 patients referred for presurgical evaluation of drug-resistant epilepsy. Patients completed four language tasks during preoperative fMRI. After subdural electrode implantation, we used DCS to localize language areas. For each stimulation site, we determined whether language positive electrode pairs intersected with significant fMRI activity clusters for language tasks. Sensitivity and specificity depended on electrode region of interest radii and statistical thresholding. For patients with at least one language positive stimulation site, an auditory description decision task provided the best trade-off between sensitivity and specificity. For patients with no language positive stimulation sites, fMRI was a dependable method of excluding eloquent language processing. Language fMRI is an effective tool for determining language lateralization before electrode implantation and is especially useful for excluding unexpected critical language areas. It can help guide subdural electrode implantation and narrow the search for eloquent cortical areas by DCS. Ann Neurol 2017;81:526-537. © 2017 American Neurological Association.

  12. [The outlook for the experimental study of the network functions of cortical cells during learning].

    Science.gov (United States)

    Gasanov, U G

    1992-01-01

    The main outcome of the experiments described in the paper is an idea on the gnostic cortical microset. Multineuronal activity recorded from the motor cortex of cats with a conditioned response to time and the following cross-correlation analysis revealed a strict distribution of interneuronal connections within the microsystems (between the adjacent neurons) and variable connections between the remote neurons during the active waiting stage of two minute interval. Additional analysis of the narrow (0.5 ms) peaks of the histograms allowed to form a view on the synaptic interaction in time. It was found that there was different temporal distribution of the spikes in the peak obtained due to correlograms of neuronal pairs. Some cortical neurons demonstrated a visible synaptic activation at the end of the waiting period when other signs of the temporary behaviour were absent. Pharmacological testing functional interneuronal connections with acetylcholine and Ca(2+)-suppressing drug EGTA have raised a question on the neurochemical specificity of the intra- and extracortical synapses.

  13. fNIRS: An Emergent Method to Document Functional Cortical Activity during Infant Movements.

    Science.gov (United States)

    Nishiyori, Ryota

    2016-01-01

    The neural basis underlying the emergence of goal-directed actions in infants has been severely understudied, with minimal empirical evidence for hypotheses proposed. This was largely due to the technological constraints of traditional neuroimaging techniques. Recently, functional near-infrared spectroscopy (fNIRS) technology has emerged as a tool developmental scientists are finding useful to examine cortical activity, particularly in young children and infants due to its greater tolerance to movements than other neuroimaging techniques. fNIRS provides an opportunity to finally begin to examine the neural underpinnings as infants develop goal-directed actions. In this methodological paper, I will outline the utility, challenges, and outcomes of using fNIRS to measure the changes in cortical activity as infants reach for an object. I will describe the advantages and limitations of the technology, the setup I used to study primary motor cortex activity during infant reaching, and example steps in the analyses processes. I will present exemplar data to illustrate the feasibility of this technique to quantify changes in hemodynamic activity as infants move. The viability of this research method opens the door to expanding studies of the development of neural activity related to goal-directed actions in infants. I encourage others to share details of techniques used, as well, including analyticals, to help this neuroimaging technology grow as others, such as EEG and fMRI have.

  14. fNIRS: An emergent method to document functional cortical activity during infant movements

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    Ryota eNishiyori

    2016-04-01

    Full Text Available The neural basis underlying the emergence of goal-directed actions in infants has been severely understudied, with minimal empirical evidence for hypotheses proposed. This was largely due to the technological constraints of traditional neuroimaging techniques. Recently, functional near-infrared spectroscopy (fNIRS technology has emerged as a tool developmental scientists are finding useful to examine cortical activity, particularly in young children and infants due to its greater tolerance to movements than other neuroimaging techniques. fNIRS provides an opportunity to finally begin to examine the neural underpinnings as infants develop goal-directed actions.In this methodological paper, I will outline the utility, challenges, and outcomes of using fNIRS to measure the changes in cortical activity as infants reach for an object. I will describe the advantages and limitations of the technology, the setup I used to study primary motor cortex activity during infant reaching, and example steps in the analyses processes. I will present exemplar data to illustrate the feasibility of this technique to quantify changes in hemodynamic activity as infants move. The viability of this research method opens the door to expanding studies of the development of neural activity related to goal-directed actions in infants. I encourage others to share details of techniques used, as well, including analyticals, to help this neuroimaging technology grow as others, such as EEG and fMRI have.

  15. The cortical activation pattern by a rehabilitation robotic hand : A functional NIRS study

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    Pyung Hun eChang

    2014-02-01

    Full Text Available Introduction: Clarification of the relationship between external stimuli and brain response has been an important topic in neuroscience and brain rehabilitation. In the current study, using functional near infrared spectroscopy (fNIRS, we attempted to investigate cortical activation patterns generated during execution of a rehabilitation robotic hand. Methods: Ten normal subjects were recruited for this study. Passive movements of the right fingers were performed using a rehabilitation robotic hand at a frequency of 0.5 Hz. We measured values of oxy-hemoglobin(HbO, deoxy-hemoglobin(HbR and total-hemoglobin(HbT in five regions of interest: the primary sensory-motor cortex (SM1, hand somatotopy of the contralateral SM1, supplementary motor area (SMA, premotor cortex (PMC, and prefrontal cortex (PFC. Results: HbO and HbT values indicated significant activation in the left SM1, left SMA, left PMC, and left PFC during execution of the rehabilitation robotic hand(uncorrected, pConclusions: Our results appear to indicate that execution of the rehabilitation robotic hand could induce cortical activation.

  16. Impact of Transcranial Magnetic Stimulation on Functional Movement Disorders: Cortical Modulation or a Behavioral Effect?

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    Béatrice Garcin

    2017-07-01

    Full Text Available IntroductionRecent studies suggest that repeated transcranial magnetic stimulation (TMS improves functional movement disorders (FMDs, but the underlying mechanisms are unclear. The objective was to determine whether the beneficial action of TMS in patients with FMDs is due to cortical neuromodulation or rather to a cognitive-behavioral effect.MethodConsecutive patients with FMDs underwent repeated low-frequency (0.25 Hz magnetic stimulation over the cortex contralateral to the symptoms or over the spinal roots [root magnetic stimulation (RMS] homolateral to the symptoms. The patients were randomized into two groups: group 1 received RMS on day 1 and TMS on day 2, while group 2 received the same treatments in reverse order. We blindly assessed the severity of movement disorders before and after each stimulation session.ResultsWe studied 33 patients with FMDs (dystonia, tremor, myoclonus, Parkinsonism, or stereotypies. The median symptom duration was 2.9 years. The magnetic stimulation sessions led to a significant improvement (>50% in 22 patients (66%. We found no difference between TMS and RMS.ConclusionWe suggest that the therapeutic benefit of TMS in patients with FMDs is due more to a cognitive-behavioral effect than to cortical neuromodulation.

  17. Cortical cross-modal plasticity following deafness measured using functional near-infrared spectroscopy.

    Science.gov (United States)

    Dewey, Rebecca S; Hartley, Douglas E H

    2015-07-01

    Evidence from functional neuroimaging studies suggests that the auditory cortex can become more responsive to visual and somatosensory stimulation following deafness, and that this occurs predominately in the right hemisphere. Extensive cross-modal plasticity in prospective cochlear implant recipients is correlated with poor speech outcomes following implantation, highlighting the potential impact of central auditory plasticity on subsequent aural rehabilitation. Conversely, the effects of hearing restoration with a cochlear implant on cortical plasticity are less well understood, since the use of most neuroimaging techniques in CI recipients is either unsafe or problematic due to the electromagnetic artefacts generated by CI stimulation. Additionally, techniques such as functional magnetic resonance imaging (fMRI) are confounded by acoustic noise produced by the scanner that will be perceived more by hearing than by deaf individuals. Subsequently it is conceivable that auditory responses to acoustic noise produced by the MR scanner may mask auditory cortical responses to non-auditory stimulation, and render inter-group comparisons less significant. Uniquely, functional near-infrared spectroscopy (fNIRS) is a silent neuroimaging technique that is non-invasive and completely unaffected by the presence of a CI. Here, we used fNIRS to study temporal-lobe responses to auditory, visual and somatosensory stimuli in thirty profoundly-deaf participants and thirty normally-hearing controls. Compared with silence, acoustic noise stimuli elicited a significant group fNIRS response in the temporal region of normally-hearing individuals, which was not seen in profoundly-deaf participants. Visual motion elicited a larger group response within the right temporal lobe of profoundly-deaf participants, compared with normally-hearing controls. However, bilateral temporal lobe fNIRS activation to somatosensory stimulation was comparable in both groups. Using fNIRS these results

  18. Maternal pre-pregnancy obesity and child ADHD symptoms, executive function and cortical thickness

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    Claudia Buss

    2012-09-01

    Full Text Available Rationale/statement of the problem : Increasing evidence suggests exposure to adverse conditions in intrauterine life may increase the risk of developing attention-deficit/hyperactivity disorder (ADHD in childhood. High maternal pre-pregnancy body mass index (BMI has been shown to predict child ADHD symptoms; however, the neurocognitive processes underlying this relationship are not known. The aim of the present study was to test the hypothesis that this association is mediated by alterations in child executive function and cortical development. Methods : A population-based cohort of 174 children (mean age = 7.3±0.9 (SD years, 55% girls was evaluated for ADHD symptoms, using the Child Behavior Checklist, and for neurocognitive function, using the Go/No-go Task. This cohort had been followed prospectively from early gestation and birth through infancy and childhood with serial measures of maternal and child prenatal and postnatal factors. In 108 children, a structural MRI scan was acquired and the association between maternal obesity and child cortical thickness was investigated using Freesurfer software. Results : Maternal pre-pregnancy BMI was a significant predictor of child ADHD symptoms (F (1,158=4.80, p = 0.03 and of child performance on the Go/No-go Task (F (1,157=8.37, p=0.004 after controlling for key potential confounding variables. A test of the mediation model revealed that the association between higher maternal pre-pregnancy BMI and child ADHD symptoms was mediated by impaired executive function (inefficient/less attentive processing; Sobel test: t=2.39 (±0.002, SEM; p=0.02. Interestingly, after controlling for key potential confounding variables pre-pregnancy obesity was furthermore associated with region-specific thinner cortices, including regions previously reported to be thinner in children with ADHD, like the prefrontal cortex. Conclusion : To the best of our knowledge, this is the first study to report the

  19. Cortical Signatures of Dyslexia and Remediation: An Intrinsic Functional Connectivity Approach

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    Koyama, Maki S.; Di Martino, Adriana; Kelly, Clare; Jutagir, Devika R.; Sunshine, Jessica; Schwartz, Susan J.; Castellanos, Francisco X.; Milham, Michael P.

    2013-01-01

    This observational, cross-sectional study investigates cortical signatures of developmental dyslexia, particularly from the perspective of behavioral remediation. We employed resting-state fMRI, and compared intrinsic functional connectivity (iFC) patterns of known reading regions (seeds) among three dyslexia groups characterized by (a) no remediation (current reading and spelling deficits), (b) partial remediation (only reading deficit remediated), and (c) full remediation (both reading and spelling deficits remediated), and a group of age- and IQ-matched typically developing children (TDC) (total N = 44, age range = 7–15 years). We observed significant group differences in iFC of two seeds located in the left posterior reading network – left intraparietal sulcus (L.IPS) and left fusiform gyrus (L.FFG). Specifically, iFC between L.IPS and left middle frontal gyrus was significantly weaker in all dyslexia groups, irrespective of remediation status/literacy competence, suggesting that persistent dysfunction in the fronto-parietal attention network characterizes dyslexia. Additionally, relative to both TDC and the no remediation group, the remediation groups exhibited stronger iFC between L.FFG and right middle occipital gyrus (R.MOG). The full remediation group also exhibited stronger negative iFC between the same L.FFG seed and right medial prefrontal cortex (R.MPFC), a core region of the default network These results suggest that behavioral remediation may be associated with compensatory changes anchored in L.FFG, which reflect atypically stronger coupling between posterior visual regions (L.FFG-R.MOG) and greater functional segregation between task-positive and task-negative regions (L.FFG-R.MPFC). These findings were bolstered by significant relationships between the strength of the identified functional connections and literacy scores. We conclude that examining iFC can reveal cortical signatures of dyslexia with particular promise for monitoring

  20. WNT4-like protein is a cortical granule component in mouse oocytes and functions in regulating preimplantation embryogenesis.

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    Liu, Min; Yang, Huei-Ting

    2016-01-01

    Mammalian cortical granules (CG) are membrane-bound organelles located in the cortex of the unfertilized oocytes. Upon fertilization, CG undergo exocytosis to function in blocking polyspermy. While cortical granules are important in fertilization, their exact biochemical composition and reproductive function have not been fully defined. In the present study, a 66 kDa wingless-type MMTV integration site family, member 4 (WNT4)-like protein, with mouse CG origin was identified. Oocytes that were double labeled with lectin Lens culinaris agglutinin (LCA) and WNT4 antibody showed colocalization of the WNT4 molecules and cortical granules. The disappearance of WNT4 molecules in the artificially activated oocytes that were devoid of cortical granules confirmed their granule origin. Following fertilization, WNT4 remained associated with zygotes and blastomeres of 2-cell and 8-cell embryos; however the amount of protein present was reduced more than 2-fold as embryos developed. Prior to implantation, WNT4 appeared to be detectable only in the trophoblast cells. Our functional study revealed that WNT4 molecules were involved in regulating zygotic cleavage and early embryogenesis. To our knowledge, this is the first study demonstrating mammalian cortical granules contain signaling molecules that are involved in the regulation of the first phase of embryonic development.

  1. The theta-syllable: a unit of speech information defined by cortical function

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    Oded eGhitza

    2013-03-01

    Full Text Available A recent commentary (Oscillators and syllables: a cautionary note. Cummins, 2012 questions the validity of a class of speech perception models inspired by the possible role of neuronal oscillations in decoding speech (e.g., Ghitza 2011, Giraud & Poeppel 2012. In arguing against the approach, Cummins raises a cautionary flag from a phonetician’s point of view. Here we respond to his arguments from an auditory processing viewpoint, referring to a phenomenological model of Ghitza (2011 taken as a representative of the criticized approach. We shall conclude by proposing the theta-syllable as an information unit defined by cortical function – an alternative to the conventional, ambiguously defined syllable. In the large context, the resulting discussion debate should be viewed as a subtext of acoustic and auditory phonetics vs. articulatory and motor theories of speech reception.

  2. Functional changes in inter- and intra-hemispheric cortical processing underlying degraded speech perception.

    Science.gov (United States)

    Bidelman, Gavin M; Howell, Megan

    2016-01-01

    Previous studies suggest that at poorer signal-to-noise ratios (SNRs), auditory cortical event-related potentials are weakened, prolonged, and show a shift in the functional lateralization of cerebral processing from left to right hemisphere. Increased right hemisphere involvement during speech-in-noise (SIN) processing may reflect the recruitment of additional brain resources to aid speech recognition or alternatively, the progressive loss of involvement from left linguistic brain areas as speech becomes more impoverished (i.e., nonspeech-like). To better elucidate the brain basis of SIN perception, we recorded neuroelectric activity in normal hearing listeners to speech sounds presented at various SNRs. Behaviorally, listeners obtained superior SIN performance for speech presented to the right compared to the left ear (i.e., right ear advantage). Source analysis of neural data assessed the relative contribution of region-specific neural generators (linguistic and auditory brain areas) to SIN processing. We found that left inferior frontal brain areas (e.g., Broca's areas) partially disengage at poorer SNRs but responses do not right lateralize with increasing noise. In contrast, auditory sources showed more resilience to noise in left compared to right primary auditory cortex but also a progressive shift in dominance from left to right hemisphere at lower SNRs. Region- and ear-specific correlations revealed that listeners' right ear SIN advantage was predicted by source activity emitted from inferior frontal gyrus (but not primary auditory cortex). Our findings demonstrate changes in the functional asymmetry of cortical speech processing during adverse acoustic conditions and suggest that "cocktail party" listening skills depend on the quality of speech representations in the left cerebral hemisphere rather than compensatory recruitment of right hemisphere mechanisms. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Sustained delivery of nicotinamide limits cortical injury and improves functional recovery following traumatic brain injury.

    Science.gov (United States)

    Goffus, Andrea M; Anderson, Gail D; Hoane, Michael

    2010-01-01

    Previously, we have demonstrated that nicotinamide (NAM), a neuroprotective soluble B-group vitamin, improves recovery of function following traumatic brain injury (TBI). However, no prior studies have examined whether NAM is beneficial following continuous infusions over 7 days post-TBI. The purpose of this study was to investigate the preclinical efficacy of NAM treatment as it might be delivered clinically; over several days by slow infusion. Rats were prepared with either unilateral controlled cortical impact (CCI) injuries or sham procedures and divided into three groups: CCI-NAM, CCI-vehicle, and sham. Thirty minutes following CCI, Alzet osmotic mini-pumps were implanted subcutaneously. NAM was delivered at a rate of 50 mg/kg/day for 7 days immediately post-CCI. On day 7 following injury, the pumps were removed and blood draws were collected for serum NAM and nicotinamide adenine dinucleotide (NAD+) analyses. Starting on day 2 post-CCI, animals were tested on a battery of sensorimotor tests (bilateral tactile adhesive removal, locomotor placing, and limb-use asymmetry). Continuous infusion of NAM resulted in a significant serum elevation in NAM, but not NAD+. Statistical analyses of the tactile removal and locomotor placing data revealed that continuous administration of NAM significantly reduced the initial magnitude of the injury deficit and improved overall recovery compared to the vehicle-treated animals. NAM treatment also significantly decreased limb-use asymmetries compared to vehicle-treated animals. The overall extent of the cortical damage was also reduced by NAM treatment. No detrimental effects were seen following continuous infusion. The present results suggest that NAM delivered via a clinically relevant therapeutic regimen may truncate behavioral damage following TBI. Thus our results offer strong support for translation into the clinical population.

  4. Sustained Delivery of Nicotinamide Limits Cortical Injury and Improves Functional Recovery Following Traumatic Brain Injury

    Directory of Open Access Journals (Sweden)

    Andrea M. Goffus

    2010-01-01

    Full Text Available Previously, we have demonstrated that nicotinamide (NAM, a neuroprotective soluble B-group vitamin, improves recovery of function following traumatic brain injury (TBI. However, no prior studies have examined whether NAM is beneficial following continuous infusions over 7 days post-TBI. The purpose of this study was to investigate the preclinical efficacy of NAM treatment as it might be delivered clinically; over several days by slow infusion. Rats were prepared with either unilateral controlled cortical impact (CCI injuries or sham procedures and divided into three groups: CCI-NAM, CCI-vehicle and sham. Thirty minutes following CCI, Alzet osmotic mini-pumps were implanted subcutaneously. NAM was delivered at a rate of 50 mg/kg/day for 7 days immediately post-CCI. On day 7 following injury, the pumps were removed and blood draws were collected for serum NAM and nicotinamide adenine dinucleotide (NAD+ analyses. Starting on day 2 post-CCI, animals were tested on a battery of sensorimotor tests (bilateral tactile adhesive removal, locomotor placing and limb-use asymmetry. Continuous infusion of NAM resulted in a significant serum elevation in NAM, but not NAD+. Statistical analyses of the tactile removal and locomotor placing data revealed that continuous administration of NAM significantly reduced the initial magnitude of the injury deficit and improved overall recovery compared to the vehicle-treated animals. NAM treatment also significantly decreased limb-use asymmetries compared to vehicle-treated animals. The overall extent of the cortical damage was also reduced by NAM treatment. No detrimental effects were seen following continuous infusion. The present results suggest that NAM delivered via a clinically relevant therapeutic regimen may truncate behavioral damage following TBI. Thus our results offer strong support for translation into the clinical population.

  5. The slow oscillation in cortical and thalamic networks: mechanisms and functions

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    Garrett T. Neske

    2016-01-01

    Full Text Available During even the most quiescent behavioral periods, the cortex and thalamus express rich spontaneous activity in the form of slow (<1 Hz, synchronous network state transitions. Throughout this so-called slow oscillation, cortical and thalamic neurons fluctuate between periods of intense synaptic activity (Up states and almost complete silence (Down states. The two decades since the original characterization of the slow oscillation in the cortex and thalamus have seen considerable advances in deciphering the cellular and network mechanisms associated with this pervasive phenomenon. There are, nevertheless, many questions regarding the slow oscillation that await more thorough illumination, particularly the mechanisms by which Up states initiate and terminate, the functional role of the rhythmic activity cycles in unconscious or minimally conscious states, and the precise relation between Up states and the activated states associated with waking behavior. Given the substantial advances in multineuronal recording and imaging methods in both in vivo and in vitro preparations, the time is ripe to take stock of our current understanding of the slow oscillation and pave the way for future investigations of its mechanisms and functions. My aim in this Review is to provide a comprehensive account of the mechanisms and functions of the slow oscillation, and to suggest avenues for further exploration.

  6. Abnormal functional brain network in epilepsy patients with focal cortical dysplasia.

    Science.gov (United States)

    Jeong, Woorim; Jin, Seung-Hyun; Kim, Museong; Kim, June Sic; Chung, Chun Kee

    2014-11-01

    Focal cortical dysplasia (FCD) is the second most common pathological entity in surgically treated neocortical focal epilepsy. Despite the recent increase of interest in network approaches derived from graph theory on epilepsy, resting state network analysis of the FCD brain has not been adequately investigated. In this study, we investigated the difference in the resting state functional network between epilepsy patients with FCD and healthy controls using whole-brain magnetoencephalography (MEG) recordings. Global mutual information (MIglob) and global efficiency (Eglob) were calculated for theta (4-7 Hz), alpha (8-12 Hz), beta (13-30 Hz), and gamma (31-45 Hz) bands in 35 epilepsy patients with FCD and 23 healthy controls. Resting state FCD brains had stronger functional connectivity (MIglob) in the beta and gamma bands and higher functional efficiency (Eglob) in the beta and gamma bands than those of the controls (ptype I and II brains in the beta band were higher than those of healthy control brains (ptype II brains were higher than those of control and FCD type I brains (ptype of FCD. The resting state network analysis could be useful in a clinical setting because we observed network differences even when there was no prominent interictal spike activity. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. A Preliminary Transcranial Magnetic Stimulation Study of Cortical Inhibition and Excitability in High-Functioning Autism and Asperger Disorder

    Science.gov (United States)

    Enticott, Peter G.; Rinehart, Nicole J.; Tonge, Bruce J.; Bradshaw, John L.; Fitzgerald, Paul B.

    2010-01-01

    Aim: Controversy surrounds the distinction between high-functioning autism (HFA) and Asperger disorder, but motor abnormalities are associated features of both conditions. This study examined motor cortical inhibition and excitability in HFA and Asperger disorder using transcranial magnetic stimulation (TMS). Method: Participants were diagnosed by…

  8. Reprint of "Cortical Reorganization of Language Functioning Following Perinatal Left MCA Stroke" [Brain and Language 105 (2008) 99-111

    Science.gov (United States)

    Tillema, Jan-Mendelt; Byars, Anna W.; Jacola, Lisa M.; Schapiro, Mark B.; Schmithorst, Vince J.; Szaflarski, Jerzy P.; Holland, Scott K.

    2008-01-01

    Objective: Functional MRI was used to determine differences in patterns of cortical activation between children who suffered perinatal left middle cerebral artery (MCA) stroke and healthy children performing a silent verb generation task. Methods: Ten children with prior perinatal left MCA stroke (age 6-16 years) and ten healthy age matched…

  9. Cortical Bone Stem Cell Therapy Preserves Cardiac Structure and Function After Myocardial Infarction.

    Science.gov (United States)

    Sharp, Thomas E; Schena, Giana J; Hobby, Alexander R; Starosta, Timothy; Berretta, Remus M; Wallner, Markus; Borghetti, Giulia; Gross, Polina; Yu, Daohai; Johnson, Jaslyn; Feldsott, Eric; Trappanese, Danielle M; Toib, Amir; Rabinowitz, Joseph E; George, Jon C; Kubo, Hajime; Mohsin, Sadia; Houser, Steven R

    2017-11-10

    Cortical bone stem cells (CBSCs) have been shown to reduce ventricular remodeling and improve cardiac function in a murine myocardial infarction (MI) model. These effects were superior to other stem cell types that have been used in recent early-stage clinical trials. However, CBSC efficacy has not been tested in a preclinical large animal model using approaches that could be applied to patients. To determine whether post-MI transendocardial injection of allogeneic CBSCs reduces pathological structural and functional remodeling and prevents the development of heart failure in a swine MI model. Female Göttingen swine underwent left anterior descending coronary artery occlusion, followed by reperfusion (ischemia-reperfusion MI). Animals received, in a randomized, blinded manner, 1:1 ratio, CBSCs (n=9; 2×10 7 cells total) or placebo (vehicle; n=9) through NOGA-guided transendocardial injections. 5-ethynyl-2'deoxyuridine (EdU)-a thymidine analog-containing minipumps were inserted at the time of MI induction. At 72 hours (n=8), initial injury and cell retention were assessed. At 3 months post-MI, cardiac structure and function were evaluated by serial echocardiography and terminal invasive hemodynamics. CBSCs were present in the MI border zone and proliferating at 72 hours post-MI but had no effect on initial cardiac injury or structure. At 3 months, CBSC-treated hearts had significantly reduced scar size, smaller myocytes, and increased myocyte nuclear density. Noninvasive echocardiographic measurements showed that left ventricular volumes and ejection fraction were significantly more preserved in CBSC-treated hearts, and invasive hemodynamic measurements documented improved cardiac structure and functional reserve. The number of EdU + cardiac myocytes was increased in CBSC- versus vehicle- treated animals. CBSC administration into the MI border zone reduces pathological cardiac structural and functional remodeling and improves left ventricular functional reserve

  10. Cortical network dynamics with time delays reveals functional connectivity in the resting brain.

    NARCIS (Netherlands)

    Ghosh, A.; Rho, Y.; McIntosh, A.R.; Kotter, R.; Jirsa, V.K.

    2008-01-01

    In absence of all goal-directed behavior, a characteristic network of cortical regions involving prefrontal and cingulate cortices consistently shows temporally coherent fluctuations. The origin of these fluctuations is unknown, but has been hypothesized to be of stochastic nature. In the present

  11. Joint cross-correlation analysis reveals complex, time-dependent functional relationship between cortical neurons and arm electromyograms

    Science.gov (United States)

    Zhuang, Katie Z.; Lebedev, Mikhail A.

    2014-01-01

    Correlation between cortical activity and electromyographic (EMG) activity of limb muscles has long been a subject of neurophysiological studies, especially in terms of corticospinal connectivity. Interest in this issue has recently increased due to the development of brain-machine interfaces with output signals that mimic muscle force. For this study, three monkeys were implanted with multielectrode arrays in multiple cortical areas. One monkey performed self-timed touch pad presses, whereas the other two executed arm reaching movements. We analyzed the dynamic relationship between cortical neuronal activity and arm EMGs using a joint cross-correlation (JCC) analysis that evaluated trial-by-trial correlation as a function of time intervals within a trial. JCCs revealed transient correlations between the EMGs of multiple muscles and neural activity in motor, premotor and somatosensory cortical areas. Matching results were obtained using spike-triggered averages corrected by subtracting trial-shuffled data. Compared with spike-triggered averages, JCCs more readily revealed dynamic changes in cortico-EMG correlations. JCCs showed that correlation peaks often sharpened around movement times and broadened during delay intervals. Furthermore, JCC patterns were directionally selective for the arm-reaching task. We propose that such highly dynamic, task-dependent and distributed relationships between cortical activity and EMGs should be taken into consideration for future brain-machine interfaces that generate EMG-like signals. PMID:25210153

  12. Cortical gene expression in spinal cord injury and repair: insight into the functional complexity of the neural regeneration program

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    Fabian eKruse

    2011-09-01

    Full Text Available Traumatic spinal cord injury (SCI results in the formation of a fibrous scar acting as a growth barrier for regenerating axons at the lesion site. We have previously shown (Klapka et al., 2005 that transient suppression of the inhibitory lesion scar in rat spinal cord leads to long distance axon regeneration, retrograde rescue of axotomized cortical motoneurons and improvement of locomotor function. Here we applied a systemic approach to investigate for the first time specific and dynamic alterations in the cortical gene expression profile following both thoracic SCI and regeneration-promoting anti-scarring treatment (AST. In order to monitor cortical gene expression we carried out microarray analyses using total RNA isolated from layer V/VI of rat sensorimotor cortex at 1-60 days post-operation (dpo. We demonstrate that cortical neurons respond to injury by massive changes in gene expression, starting as early as 1 dpo. AST, in turn, results in profound modifications of the lesion-induced expression profile. The treatment attenuates SCI-triggered transcriptional changes of genes related to inhibition of axon growth and impairment of cell survival, while upregulating the expression of genes associated with axon outgrowth, cell protection and neural development. Thus, AST not only modifies the local environment impeding spinal cord regeneration by reduction of fibrous scarring in the injured spinal cord, but, in addition, strikingly changes the intrinsic capacity of cortical pyramidal neurons towards enhanced cell maintenance and axonal regeneration.

  13. Renal cortical volume measured using automatic contouring software for computed tomography and its relationship with BMI, age and renal function

    Energy Technology Data Exchange (ETDEWEB)

    Muto, Natalia Sayuri, E-mail: nataliamuto@gmail.com [Department of Radiology, Hokkaido University Hospital, N15 W7, kita-ku, Sapporo City, 0608638 (Japan); Kamishima, Tamotsu, E-mail: ktamotamo2@yahoo.co.jp [Department of Radiology, Hokkaido University Hospital, N15 W7, kita-ku, Sapporo City, 0608638 (Japan); Harris, Ardene A., E-mail: ardene_b@yahoo.com [Department of Radiology, Hokkaido University Hospital, N15 W7, kita-ku, Sapporo City, 0608638 (Japan); Kato, Fumi, E-mail: fumikato@med.hokudai.ac.jp [Department of Radiology, Hokkaido University Hospital, N15 W7, kita-ku, Sapporo City, 0608638 (Japan); Onodera, Yuya, E-mail: yuyaonodera@med.hokudai.ac.jp [Department of Radiology, Hokkaido University Hospital, N15 W7, kita-ku, Sapporo City, 0608638 (Japan); Terae, Satoshi, E-mail: saterae@yahoo.co.jp [Department of Radiology, Hokkaido University Hospital, N15 W7, kita-ku, Sapporo City, 0608638 (Japan); Shirato, Hiroki, E-mail: shirato@med.hokudai.ac.jp [Department of Radiology, Hokkaido University Hospital, N15 W7, kita-ku, Sapporo City, 0608638 (Japan)

    2011-04-15

    Purpose: To evaluate the relationship between renal cortical volume, measured by an automatic contouring software, with body mass index (BMI), age and renal function. Materials and methods: The study was performed in accordance to the institutional guidelines at our hospital. Sixty-four patients (34 men, 30 women), aged 19 to 79 years had their CT scans for diagnosis or follow-up of hepatocellular carcinoma retrospectively examined by a computer workstation using a software that automatically contours the renal cortex and the renal parenchyma. Body mass index and estimated glomerular filtration rate (eGFR) were calculated based on data collected. Statistical analysis was done using the Student t-test, multiple regression analysis, and intraclass correlation coefficient (ICC). Results: The ICC for total renal and renal cortical volumes were 0.98 and 0.99, respectively. Renal volume measurements yielded a mean cortical volume of 105.8 cm{sup 3} {+-} 28.4 SD, mean total volume of 153 cm{sup 3} {+-} 39 SD and mean medullary volume of 47.8 cm{sup 3} {+-} 19.5 SD. The correlation between body weight/height/BMI and both total renal and cortical volumes presented r = 0.6, 0.6 and 0.4, respectively, p < 0.05, while the correlation between renal cortex and age was r = -0.3, p < 0.05. eGFR showed correlation with renal cortical volume r = 0.6, p < 0.05. Conclusion: This study demonstrated that renal cortical volume had a moderate positive relationship with BMI, moderate negative relationship with age, and a strong positive relationship with the renal function, and provided a new method to routinely produce volumetric assessment of the kidney.

  14. Malnutrition and brain function: experimental studies using the phenomenon of cortical spreading depression.

    Science.gov (United States)

    Guedes, R C; Monteiro, J S; Teodósio, N R

    1996-12-01

    Depending on its intensity and duration, nutritional deficiency can disrupt the structure and function of the nervous system of humans and other mammals, with consequences more or less devastating for the whole organism, particularly in the early postnatal life, when body growth is very rapid and the need for proteins, calories and other nutrients is greatest. In this review, electrophysiological data are presented regarding the use of the phenomenon of cortical spreading depression (CSD) to study effects of malnutrition on the brain. Several conditions of clinical importance and that are known to alter brain function are shown also to influence CSD features in experimental animals. Some of these conditions, (e.g., pharmacological manipulation of neurotransmitter systems, dietary treatment with Lithium, acute hyperglycemia, hypothyroidism, aging and environmental stimulation) decrease CSD susceptibility, while other conditions increase it, as, for example, systemic reduction of extracellular chloride levels, deprivation of REM-sleep, acute hypoglycemia, treatment with diazepam, consumption of ethanol and malnutrition. Particular emphasis is laid on the effect of early environmental enrichment on CSD in normal and malnourished animals. Our results suggest that such effect is more evident in the malnourished brain, as compared to the well-nourished one. The data also show that malnutrition alters the brain responsivity to some CSD-facilitatory or inhibitory agents. The underlying mechanisms to explain the observed effects are discussed.

  15. Long-lasting enhancements of memory and hippocampal-cortical functional connectivity following multiple-day targeted noninvasive stimulation.

    Science.gov (United States)

    Wang, Jane X; Voss, Joel L

    2015-08-01

    Noninvasive stimulation can alter the function of brain networks, although the duration of neuroplastic changes are uncertain and likely vary for different networks and stimulation parameters. We have previously shown that multiple-day repetitive transcranial magnetic stimulation can influence targeted hippocampal-cortical networks, producing increased functional MRI connectivity of these networks and concomitant improvements in memory that outlast stimulation by ∼24 h. Here, we present new analyses showing that multiple-day targeted stimulation of hippocampal-cortical networks produces even longer-lasting enhancement. The ability to learn novel, arbitrary face-word pairings improved over five consecutive daily stimulation sessions, and this improvement remained robust at follow-up testing performed an average of 15 days later. Furthermore, stimulation increased functional MRI connectivity of the targeted portion of the hippocampus with distributed regions of the posterior hippocampal-cortical network, and these changes in connectivity remained robust at follow-up testing. Neuroplastic changes of hippocampal-cortical networks caused by multiple-day noninvasive stimulation therefore persist for extended periods. These findings have implications for the design of multiple-day stimulation experiments and for the development of stimulation-based interventions for memory disorders. © 2015 Wiley Periodicals, Inc.

  16. Mapping of cortical language function by functional magnetic resonance imaging and repetitive navigated transcranial magnetic stimulation in 40 healthy subjects.

    Science.gov (United States)

    Sollmann, Nico; Ille, Sebastian; Boeckh-Behrens, Tobias; Ringel, Florian; Meyer, Bernhard; Krieg, Sandro M

    2016-07-01

    Functional magnetic resonance imaging (fMRI) is considered to be the standard method regarding non-invasive language mapping. However, repetitive navigated transcranial magnetic stimulation (rTMS) gains increasing importance with respect to that purpose. However, comparisons between both methods are sparse. We performed fMRI and rTMS language mapping of the left hemisphere in 40 healthy, right-handed subjects in combination with the tasks that are most commonly used in the neurosurgical context (fMRI: word-generation = WGEN task; rTMS: object-naming = ON task). Different rTMS error rate thresholds (ERTs) were calculated, and Cohen's kappa coefficient and the cortical parcellation system (CPS) were used for systematic comparison of the two techniques. Overall, mean kappa coefficients were low, revealing no distinct agreement. We found the highest agreement for both techniques when using the 2-out-of-3 rule (CPS region defined as language positive in terms of rTMS if at least 2 out of 3 stimulations led to a naming error). However, kappa for this threshold was only 0.24 (kappa of <0, 0.01-0.20, 0.21-0.40, 0.41-0.60, 0.61-0.80 and 0.81-0.99 indicate less than chance, slight, fair, moderate, substantial and almost perfect agreement, respectively). Because of the inherent differences in the underlying physiology of fMRI and rTMS, the different tasks used and the impossibility of verifying the results via direct cortical stimulation (DCS) in the population of healthy volunteers, one must exercise caution in drawing conclusions about the relative usefulness of each technique for language mapping. Nevertheless, this study yields valuable insights into these two mapping techniques for the most common language tasks currently used in neurosurgical practice.

  17. Resting-State Functional Connectivity Changes Between Dentate Nucleus and Cortical Social Brain Regions in Autism Spectrum Disorders.

    Science.gov (United States)

    Olivito, Giusy; Clausi, Silvia; Laghi, Fiorenzo; Tedesco, Anna Maria; Baiocco, Roberto; Mastropasqua, Chiara; Molinari, Marco; Cercignani, Mara; Bozzali, Marco; Leggio, Maria

    2017-04-01

    Autism spectrum disorders (ASDs) are known to be characterized by restricted and repetitive behaviors and interests and by impairments in social communication and interactions mainly including "theory of mind" (ToM) processes. The cerebellum has emerged as one of the brain regions affected by ASDs. As the cerebellum is known to influence cerebral cortex activity via cerebello-thalamo-cortical (CTC) circuits, it has been proposed that cerebello-cortical "disconnection" could in part underlie autistic symptoms. We used resting-state (RS) functional magnetic resonance imaging (fMRI) to investigate the potential RS connectivity changes between the cerebellar dentate nucleus (DN) and the CTC circuit targets, that may contribute to ASD pathophysiology. When comparing ASD patients to controls, we found decreased connectivity between the left DN and cerebral regions known to be components of the ToM network and the default mode network, implicated in specific aspects of mentalizing, social cognition processing, and higher order emotional processes. Further, a pattern of overconnectivity was also detected between the left DN and the supramodal cerebellar lobules associated with the default mode network. The presented RS-fMRI data provide evidence that functional connectivity (FC) between the dentate nucleus and the cerebral cortex is altered in ASD patients. This suggests that the dysfunction reported within the cerebral cortical network, typically related to social features of ASDs, may be at least partially related to an impaired interaction between cerebellum and key cortical social brain regions.

  18. Cortical Neuroprosthesis Merges Visible and Invisible Light Without Impairing Native Sensory Function.

    Science.gov (United States)

    Thomson, Eric E; Zea, Ivan; Windham, William; Thenaisie, Yohann; Walker, Cameron; Pedowitz, Jason; França, Wendy; Graneiro, Ana L; Nicolelis, Miguel A L

    2017-01-01

    Adult rats equipped with a sensory prosthesis, which transduced infrared (IR) signals into electrical signals delivered to somatosensory cortex (S1), took approximately 4 d to learn a four-choice IR discrimination task. Here, we show that when such IR signals are projected to the primary visual cortex (V1), rats that are pretrained in a visual-discrimination task typically learn the same IR discrimination task on their first day of training. However, without prior training on a visual discrimination task, the learning rates for S1- and V1-implanted animals converged, suggesting there is no intrinsic difference in learning rate between the two areas. We also discovered that animals were able to integrate IR information into the ongoing visual processing stream in V1, performing a visual-IR integration task in which they had to combine IR and visual information. Furthermore, when the IR prosthesis was implanted in S1, rats showed no impairment in their ability to use their whiskers to perform a tactile discrimination task. Instead, in some rats, this ability was actually enhanced. Cumulatively, these findings suggest that cortical sensory neuroprostheses can rapidly augment the representational scope of primary sensory areas, integrating novel sources of information into ongoing processing while incurring minimal loss of native function.

  19. Cortical representation of facial and tongue movements: a task functional magnetic resonance imaging study.

    Science.gov (United States)

    Xiao, Fu-Long; Gao, Pei-Yi; Qian, Tian-Yi; Sui, Bin-Bin; Xue, Jing; Zhou, Jian; Lin, Yan

    2017-05-01

    Functional magnetic resonance imaging (fMRI) mapping can present the activated cortical area during movement, while little is known about precise location in facial and tongue movements. To investigate the representation of facial and tongue movements by task fMRI. Twenty right-handed healthy subjects were underwent block design task fMRI examination. Task movements included lip pursing, cheek bulging, grinning and vertical tongue excursion. Statistical parametric mapping (SPM8) was applied to analysis the data. One-sample t-test was used to calculate the common activation area between facial and tongue movements. Also, paired t-test was used to test for areas of over- or underactivation in tongue movement compared with each group of facial movements. The common areas within facial and tongue movements suggested the similar motor circuits of activation in both movements. Prior activation in tongue movement was situated laterally and inferiorly in sensorimotor area relative to facial movements. Prior activation of tongue movement was investigated in left superior parietal lobe relative to lip pursing. Also, prior activation in bilateral cuneus lobe in grinning compared with tongue movement was detected. © 2015 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  20. Family Nurture Intervention in preterm infants alters frontal cortical functional connectivity assessed by EEG coherence.

    Science.gov (United States)

    Myers, M M; Grieve, P G; Stark, R I; Isler, J R; Hofer, M A; Yang, J; Ludwig, R J; Welch, M G

    2015-07-01

    To assess the impact of Family Nurture Intervention (FNI) on cortical function in preterm infants at term age. Family Nurture Intervention is a NICU-based intervention designed to establish emotional connection between mothers and preterm infants. Infants born at 26-34 weeks postmenstrual age (PMA) were divided into two groups, standard care (SC, N = 49) and FNI (FNI, N = 56). Infants had EEG recordings of ~one hour duration with 124 lead nets between 37 and 44 weeks PMA. Coherence was measured between all pairs of electrodes in ten frequency bands. Data were summarised both within and between 12 regions during two sleep states (active, quiet). Coherence levels were negatively correlated with PMA age in both groups. As compared to SC infants, FNI infants showed significantly lower levels of EEG coherence (1-18 Hz) largely within and between frontal regions. Coherence in FNI infants was decreased in regions where we previously found robust increases in EEG power. As coherence decreases with age, results suggest that FNI may accelerate brain maturation particularly in frontal brain regions, which have been shown in research by others to be involved in regulation of attention, cognition and emotion regulation; domains deficient in preterm infants. ©2015 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.

  1. Left and Right Amygdala - Mediofrontal Cortical Functional Connectivity Is Differentially Modulated by Harm Avoidance

    Science.gov (United States)

    Baeken, Chris; Marinazzo, Daniele; Van Schuerbeek, Peter; Wu, Guo-Rong; De Mey, Johan; Luypaert, Robert; De Raedt, Rudi

    2014-01-01

    Background The left and right amygdalae are key regions distinctly involved in emotion-regulation processes. Individual differences, such as personality features, may affect the implicated neurocircuits. The lateralized amygdala affective processing linked with the temperament dimension Harm Avoidance (HA) remains poorly understood. Resting state functional connectivity imaging (rsFC) may provide more insight into these neuronal processes. Methods In 56 drug-naive healthy female subjects, we have examined the relationship between the personality dimension HA on lateralized amygdala rsFC. Results Across all subjects, left and right amygdalae were connected with distinct regions mainly within the ipsilateral hemisphere. Females scoring higher on HA displayed stronger left amygdala rsFC with ventromedial prefrontal cortical (vmPFC) regions involved in affective disturbances. In high HA scorers, we also observed stronger right amygdala rsFC with the dorsomedial prefrontal cortex (dmPFC), which is implicated in negative affect regulation. Conclusions In healthy females, left and right amygdalae seem implicated in distinct mPFC brain networks related to HA and may represent a vulnerability marker for sensitivity to stress and anxiety (disorders). PMID:24760033

  2. Combined structural and functional imaging reveals cortical deactivations in grapheme-colour synaesthesia

    Directory of Open Access Journals (Sweden)

    Erik eO'Hanlon

    2013-10-01

    Full Text Available Synaesthesia is a heritable condition in which particular stimuli generate specific and consistent sensory percepts or associations in another modality or processing stream. Functional neuroimaging studies have identified potential correlates of these experiences, including, in some but not all cases, the hyperactivation of visuotemporal areas and of parietal areas thought to be involved in perceptual binding. Structural studies have identified a similarly variable spectrum of differences between synaesthetes and controls. However, it remains unclear the extent to which these neural correlates reflect the synaesthetic experience itself or additional phenotypes associated with the condition. Here, we acquired both structural and functional neuroimaging data comparing thirteen grapheme-colour synaesthetes with eleven non-synaesthetes. Using voxel-based morphometry and diffusion tensor imaging, we identify a number of clusters of increased volume of grey matter, of white matter or of increased fractional anisotropy in synaesthetes versus controls. To assess the possible involvement of these areas in the synaesthetic experience, we used nine areas of increased grey matter volume as regions of interest in an fMRI experiment that characterised the contrast in response to stimuli which induced synaesthesia (i.e. letters versus those which did not (non-meaningful symbols. Two of these areas, in left lateral occipital cortex and in postcentral gyrus, showed sensitivity to this contrast in synaesthetes but not controls. Unexpectedly, in both regions, the letter stimuli produced a strong negative BOLD signal in synaesthetes. An additional whole-brain fMRI analysis identified fourteen areas, three of which were driven mainly by a negative BOLD response to letters in synaesthetes. Our findings suggest that cortical deactivations may be involved in the conscious experience of internally generated synaesthetic percepts

  3. Combined structural and functional imaging reveals cortical deactivations in grapheme-color synaesthesia.

    Science.gov (United States)

    O'Hanlon, Erik; Newell, Fiona N; Mitchell, Kevin J

    2013-01-01

    Synaesthesia is a heritable condition in which particular stimuli generate specific and consistent sensory percepts or associations in another modality or processing stream. Functional neuroimaging studies have identified potential correlates of these experiences, including, in some but not all cases, the hyperactivation of visuotemporal areas and of parietal areas thought to be involved in perceptual binding. Structural studies have identified a similarly variable spectrum of differences between synaesthetes and controls. However, it remains unclear the extent to which these neural correlates reflect the synaesthetic experience itself or additional phenotypes associated with the condition. Here, we acquired both structural and functional neuroimaging data comparing thirteen grapheme-color synaesthetes with eleven non-synaesthetes. Using voxel-based morphometry and diffusion tensor imaging, we identify a number of clusters of increased volume of gray matter, of white matter or of increased fractional anisotropy in synaesthetes vs. controls. To assess the possible involvement of these areas in the synaesthetic experience, we used nine areas of increased gray matter volume as regions of interest in an fMRI experiment that characterized the contrast in response to stimuli which induced synaesthesia (i.e., letters) vs. those which did not (non-meaningful symbols). Four of these areas showed sensitivity to this contrast in synaesthetes but not controls. Unexpectedly, in two of them, in left lateral occipital cortex and in postcentral gyrus, the letter stimuli produced a strong negative BOLD signal in synaesthetes. An additional whole-brain fMRI analysis identified 14 areas, three of which were driven mainly by a negative BOLD response to letters in synaesthetes. Our findings suggest that cortical deactivations may be involved in the conscious experience of internally generated synaesthetic percepts.

  4. Influence of cognitive strategies on the pattern of cortical activation during mental subtraction. A functional imaging study in human subjects.

    Science.gov (United States)

    Burbaud, P; Camus, O; Guehl, D; Bioulac, B; Caillé, J; Allard, M

    2000-06-16

    Functional magnetic resonance imaging (fMRI) at 1.5 T was used to investigate the influence of cognitive strategies on cortical activation during mental calculation. Twenty-nine right-handed subjects performed a serial subtraction of prime numbers. Even though a common corpus of brain areas was activated during this mental calculation, differences appeared between subjects in function of their spontaneous cognitive strategy. In subjects using a so called verbal strategy (n=15), the main activation was located in the whole left dorsolateral frontal cortex with a little activation of the inferior parietal cortex. In subjects using a so called visual strategy (n=14), a bilateral activation in the prefrontal cortex and a high activation in the left inferior parietal cortex were observed. These results demonstrate that numbers are processed through a distributed network of cortical areas, the lateralization of which is clearly influenced by subject strategy.

  5. Functional magnetic resonance imaging suggests automatization of the cortical response to inspiratory threshold loading in humans.

    Science.gov (United States)

    Raux, Mathieu; Tyvaert, Louise; Ferreira, Michael; Kindler, Félix; Bardinet, Eric; Karachi, Carine; Morelot-Panzini, Capucine; Gotman, Jean; Pike, G Bruce; Koski, Lisa; Similowski, Thomas

    2013-12-01

    Inspiratory threshold loading (ITL) induces cortical activation. It is sustained over time and is resistant to distraction, suggesting automaticity. We hypothesized that ITL-induced changes in cerebral activation may differ between single-breath ITL and continuous ITL, with differences resembling those observed after cortical automatization of motor tasks. We analyzed the brain blood oxygen level dependent (BOLD) signal of 11 naive healthy volunteers during 5 min of random, single-breath ITL and 5 min of continuous ITL. Single-breath ITL increased BOLD in many areas (premotor cortices, bilateral insula, cerebellum, reticular formation of the lateral mesencephalon) and decreased BOLD in regions co-localizing with the default mode network. Continuous ITL induced signal changes in a limited number of areas (supplementary motor area). These differences are comparable to those observed before and after overlearning of motor tasks. We conclude that the respiratory-related cortical activation observed in response to ITL is likely due to automated, attention-independent mechanisms. Also, ITL activates cortical circuits right from the first breath. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Using functional near-infrared spectroscopy (fNIRS) to detect the prefrontal cortical responses to deception under different motivations

    OpenAIRE

    Li, Fang; Zhu, Huilin; Gao, Qianqian; Xu, Guixiong; Li, Xinge; Hu, Ziqiang; He, Sailing

    2015-01-01

    In this study, functional near-infrared spectroscopy (fNIRS) was adopted to investigate the prefrontal cortical responses to deception under different motivations. By using a feigned memory impairment paradigm, 19 healthy adults were asked to deceive under the two different motivations: to obtain rewards and to avoid punishments. Results indicated that when deceiving for obtaining rewards, there was greater neural activation in the right inferior frontal gyrus (IFG) than the control condition...

  7. Exploring the cortical and subcortical functional magnetic resonance imaging changes associated with freezing in Parkinson's disease.

    Science.gov (United States)

    Shine, James M; Matar, Elie; Ward, Philip B; Bolitho, Samuel J; Gilat, Moran; Pearson, Mark; Naismith, Sharon L; Lewis, Simon J G

    2013-04-01

    Freezing of gait is a devastating symptom of advanced Parkinson's disease yet the neural correlates of this phenomenon remain poorly understood. In this study, severity of freezing of gait was assessed in 18 patients with Parkinson's disease on a series of timed 'up and go' tasks, in which all patients suffered from episodes of clinical freezing of gait. The same patients also underwent functional magnetic resonance imaging with a virtual reality gait paradigm, performance on which has recently been shown to correlate with actual episodes of freezing of gait. Statistical parametric maps were created that compared the blood oxygen level-dependent response associated with paroxysmal motor arrests (freezing) to periods of normal motor output. The results of a random effects analysis revealed that these events were associated with a decreased blood oxygen level-dependent response in sensorimotor regions and an increased response within frontoparietal cortical regions. These signal changes were inversely correlated with the severity of clinical freezing of gait. Motor arrests were also associated with decreased blood oxygen level-dependent signal bilaterally in the head of caudate nucleus, the thalamus and the globus pallidus internus. Utilizing a mixed event-related/block design, we found that the decreased blood oxygen level-dependent response in the globus pallidus and the subthalamic nucleus persisted even after controlling for the effects of cognitive load, a finding which supports the notion that paroxysmal increases in basal ganglia outflow are associated with the freezing phenomenon. This method also revealed a decrease in the blood oxygen level-dependent response within the mesencephalic locomotor region during motor arrests, the magnitude of which was positively correlated with the severity of clinical freezing of gait. These results provide novel insights into the pathophysiology underlying freezing of gait and lend support to models of freezing of gait that

  8. Distinct patterns of functional and effective connectivity between perirhinal cortex and other cortical regions in recognition memory and perceptual discrimination.

    Science.gov (United States)

    O'Neil, Edward B; Protzner, Andrea B; McCormick, Cornelia; McLean, D Adam; Poppenk, Jordan; Cate, Anthony D; Köhler, Stefan

    2012-01-01

    Traditionally, the medial temporal lobe (MTL) is thought to be dedicated to declarative memory. Recent evidence challenges this view, suggesting that perirhinal cortex (PrC), which interfaces the MTL with the ventral visual pathway, supports highly integrated object representations in recognition memory and perceptual discrimination. Even with comparable representational demands, perceptual and memory tasks differ in numerous task demands and the subjective experience they evoke. Here, we tested whether such differences are reflected in distinct patterns of connectivity between PrC and other cortical regions, including differential involvement of prefrontal control processes. We examined functional magnetic resonance imaging data for closely matched perceptual and recognition memory tasks for faces that engaged right PrC equivalently. Multivariate seed analyses revealed distinct patterns of interactions: Right ventrolateral prefrontal and posterior cingulate cortices exhibited stronger functional connectivity with PrC in recognition memory; fusiform regions were part of the pattern that displayed stronger functional connectivity with PrC in perceptual discrimination. Structural equation modeling revealed distinct patterns of effective connectivity that allowed us to constrain interpretation of these findings. Overall, they demonstrate that, even when MTL structures show similar involvement in recognition memory and perceptual discrimination, differential neural mechanisms are reflected in the interplay between the MTL and other cortical regions.

  9. Modelling and analysis of local field potentials for studying the function of cortical circuits.

    Science.gov (United States)

    Einevoll, Gaute T; Kayser, Christoph; Logothetis, Nikos K; Panzeri, Stefano

    2013-11-01

    The past decade has witnessed a renewed interest in cortical local field potentials (LFPs)--that is, extracellularly recorded potentials with frequencies of up to ~500 Hz. This is due to both the advent of multielectrodes, which has enabled recording of LFPs at tens to hundreds of sites simultaneously, and the insight that LFPs offer a unique window into key integrative synaptic processes in cortical populations. However, owing to its numerous potential neural sources, the LFP is more difficult to interpret than are spikes. Careful mathematical modelling and analysis are needed to take full advantage of the opportunities that this signal offers in understanding signal processing in cortical circuits and, ultimately, the neural basis of perception and cognition.

  10. Docosahexaenoic acid biostatus is associated with event-related functional connectivity in cortical attention networks of typically developing children.

    Science.gov (United States)

    Almeida, Daniel M; Jandacek, Ronald J; Weber, Wade A; McNamara, Robert K

    2017-05-01

    Although extant preclinical evidence suggests that the long-chain omega-3 fatty acid docosahexaenoic acid (DHA) is important for neurodevelopment, little is known about its role in human cortical structural and functional maturation. In the present cross-sectional study, we investigated the relationship between DHA biostatus and functional connectivity in cortical attention networks of typically developing children. Male children (aged 8-10 years, n = 36) were divided into 'low-DHA' (n = 18) and 'high-DHA' (n = 18) biostatus groups by a median split of erythrocyte DHA levels. Event-related functional connectivity during the performance of a sustained attention task (identical pairs continuous performance task (CPT-IP)) was conducted using functional magnetic resonance imaging. A voxelwise approach used the anterior cingulate cortex (ACC) as the seed-region. Erythrocyte DHA composition in the low-DHA group (2.6 ± 0.9%) was significantly lower than the high-DHA group (4.1 ± 1.1%, P ≤ 0.0001). Fish intake frequency was greater in the high-DHA group (P = 0.003) and was positively correlated with DHA levels among all subjects. The low-DHA group exhibited reduced functional connectivity between the ACC and the ventrolateral prefrontal cortex, insula, precuneus, superior parietal lobule, middle occipital gyrus, inferior temporal gyrus, and lingual gyrus compared with the high-DHA group (P DHA group did not exhibit greater ACC functional connectivity with any region compared with the high-DHA group. On the CPT-IP task, the low-DHA group had slower reaction time (P = 0.03) which was inversely correlated with erythrocyte DHA among all subjects. These data suggest that low-DHA biostatus is associated with reduced event-related functional connectivity in cortical attention networks of typically developing children.

  11. Functional connectivity changes between parietal and prefrontal cortices in primary insomnia patients: evidence from resting-state fMRI

    Science.gov (United States)

    2014-01-01

    Background Primary insomnia can severely impair daytime function by disrupting attention and working memory and imposes a danger to self and others by increasing the risk of accidents. We speculated that the neurobiological changes impeding working memory in primary insomnia patients would be revealed by resting-state functional MRI (R-fMRI), which estimates the strength of cortical pathways by measuring local and regional correlations in blood oxygen level dependent (BOLD) signs independent of specific task demands. Methods We compared the R-fMRI activity patterns of 15 healthy controls to 15 primary insomnia patients (all 30 participants were right-handed) using a 3.0 T MRI scanner. The SPM8 and REST1.7 software packages were used for preprocessing and analysis. Activity was expressed relative to the superior parietal lobe (SPL, the seed region) to reveal differences in functional connectivity to other cortical regions implicated in spatial working memory. Result In healthy controls, bilateral SPL activity was associated with activity in the posterior cingulate gyrus, precuneus, ventromedial prefrontal cortex, and superior frontal gyrus, indicating functional connectivity between these regions. Strong functional connectivity between the SPL and bilateral pre-motor cortex, bilateral supplementary motor cortex, and left dorsolateral prefrontal cortex was observed in both the control group and the primary insomnia group. However, the strength of several other functional connectivity pathways to the SPL exhibited significant group differences. Compared to healthy controls, connectivity in the primary insomnia group was stronger between the bilateral SPL and the right ventral anterior cingulate cortex, left ventral posterior cingulate cortex, right splenium of the corpus callosum, right pars triangularis (right inferior frontal gyrus/Broca’s area), and right insular lobe, while connectivity was weaker between the SPL and right superior frontal gyrus (dorsolateral

  12. Development of visual cortical function in infant macaques: A BOLD fMRI study.

    Directory of Open Access Journals (Sweden)

    Tom J Van Grootel

    Full Text Available Functional brain development is not well understood. In the visual system, neurophysiological studies in nonhuman primates show quite mature neuronal properties near birth although visual function is itself quite immature and continues to develop over many months or years after birth. Our goal was to assess the relative development of two main visual processing streams, dorsal and ventral, using BOLD fMRI in an attempt to understand the global mechanisms that support the maturation of visual behavior. Seven infant macaque monkeys (Macaca mulatta were repeatedly scanned, while anesthetized, over an age range of 102 to 1431 days. Large rotating checkerboard stimuli induced BOLD activation in visual cortices at early ages. Additionally we used static and dynamic Glass pattern stimuli to probe BOLD responses in primary visual cortex and two extrastriate areas: V4 and MT-V5. The resulting activations were analyzed with standard GLM and multivoxel pattern analysis (MVPA approaches. We analyzed three contrasts: Glass pattern present/absent, static/dynamic Glass pattern presentation, and structured/random Glass pattern form. For both GLM and MVPA approaches, robust coherent BOLD activation appeared relatively late in comparison to the maturation of known neuronal properties and the development of behavioral sensitivity to Glass patterns. Robust differential activity to Glass pattern present/absent and dynamic/static stimulus presentation appeared first in V1, followed by V4 and MT-V5 at older ages; there was no reliable distinction between the two extrastriate areas. A similar pattern of results was obtained with the two analysis methods, although MVPA analysis showed reliable differential responses emerging at later ages than GLM. Although BOLD responses to large visual stimuli are detectable, our results with more refined stimuli indicate that global BOLD activity changes as behavioral performance matures. This reflects an hierarchical development of

  13. Functional and spatial segregation within the inferior frontal and superior temporal cortices during listening, articulation imagery, and production of vowels.

    Science.gov (United States)

    Rampinini, Alessandra Cecilia; Handjaras, Giacomo; Leo, Andrea; Cecchetti, Luca; Ricciardi, Emiliano; Marotta, Giovanna; Pietrini, Pietro

    2017-12-05

    Classical models of language localize speech perception in the left superior temporal and production in the inferior frontal cortex. Nonetheless, neuropsychological, structural and functional studies have questioned such subdivision, suggesting an interwoven organization of the speech function within these cortices. We tested whether sub-regions within frontal and temporal speech-related areas retain specific phonological representations during both perception and production. Using functional magnetic resonance imaging and multivoxel pattern analysis, we showed functional and spatial segregation across the left fronto-temporal cortex during listening, imagery and production of vowels. In accordance with classical models of language and evidence from functional studies, the inferior frontal and superior temporal cortices discriminated among perceived and produced vowels respectively, also engaging in the non-classical, alternative function - i.e. perception in the inferior frontal and production in the superior temporal cortex. Crucially, though, contiguous and non-overlapping sub-regions within these hubs performed either the classical or non-classical function, the latter also representing non-linguistic sounds (i.e., pure tones). Extending previous results and in line with integration theories, our findings not only demonstrate that sensitivity to speech listening exists in production-related regions and vice versa, but they also suggest that the nature of such interwoven organisation is built upon low-level perception.

  14. Cortical and subcortical mapping of language areas: correlation of functional MRI and tractography in a 3T scanner with intraoperative cortical and subcortical stimulation in patients with brain tumors located in eloquent areas.

    Science.gov (United States)

    Jiménez de la Peña, M; Gil Robles, S; Recio Rodríguez, M; Ruiz Ocaña, C; Martínez de Vega, V

    2013-01-01

    To describe the detection of cortical areas and subcortical pathways involved in language observed in MRI activation studies and tractography in a 3T MRI scanner and to correlate the findings of these functional studies with direct intraoperative cortical and subcortical stimulation. We present a series of 14 patients with focal brain tumors adjacent to eloquent brain areas. All patients underwent neuropsychological evaluation before and after surgery. All patients underwent MRI examination including structural sequences, perfusion imaging, spectroscopy, functional imaging to determine activation of motor and language areas, and 3D tractography. All patients underwent cortical mapping through cortical and subcortical stimulation during the operation to resect the tumor. Postoperative follow-up studies were done 24 hours after surgery. The correlation of motor function and of the corticospinal tract determined by functional MRI and tractography with intraoperative mapping of cortical and subcortical motor areas was complete. The eloquent brain areas of language expression and reception were strongly correlated with intraoperative cortical mapping in all but two cases (a high grade infiltrating glioma and a low grade glioma located in the frontal lobe). 3D tractography identified the arcuate fasciculus, the lateral part of the superior longitudinal fasciculus, the subcallosal fasciculus, the inferior fronto-occipital fasciculus, and the optic radiations, which made it possible to mark the limits of the resection. The correlation with the subcortical mapping of the anatomic arrangement of the fasciculi with respect to the lesions was complete. The best treatment for brain tumors is maximum resection without associated deficits, so high quality functional studies are necessary for preoperative planning. Copyright © 2011 SERAM. Published by Elsevier Espana. All rights reserved.

  15. The natural hallucinogen 5-MeO-DMT, component of Ayahuasca, disrupts cortical function in rats: reversal by antipsychotic drugs.

    Science.gov (United States)

    Riga, Maurizio S; Soria, Guadalupe; Tudela, Raúl; Artigas, Francesc; Celada, Pau

    2014-08-01

    5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT) is a natural hallucinogen component of Ayahuasca, an Amazonian beverage traditionally used for ritual, religious and healing purposes that is being increasingly used for recreational purposes in US and Europe. 5MeO-DMT is of potential interest for schizophrenia research owing to its hallucinogenic properties. Two other psychotomimetic agents, phencyclidine and 2,5-dimethoxy-4-iodo-phenylisopropylamine (DOI), markedly disrupt neuronal activity and reduce the power of low frequency cortical oscillations (5-MeO-DMT on cortical function and its potential reversal by antipsychotic drugs. Moreover, regional brain activity was assessed by blood-oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI). 5-MeO-DMT disrupted mPFC activity, increasing and decreasing the discharge of 51 and 35% of the recorded pyramidal neurons, and reducing (-31%) the power of LFCO. The latter effect depended on 5-HT1A and 5-HT2A receptor activation and was reversed by haloperidol, clozapine, risperidone, and the mGlu2/3 agonist LY379268. Likewise, 5-MeO-DMT decreased BOLD responses in visual cortex (V1) and mPFC. The disruption of cortical activity induced by 5-MeO-DMT resembles that produced by phencyclidine and DOI. This, together with the reversal by antipsychotic drugs, suggests that the observed cortical alterations are related to the psychotomimetic action of 5-MeO-DMT. Overall, the present model may help to understand the neurobiological basis of hallucinations and to identify new targets in antipsychotic drug development.

  16. Altered basal ganglia-cortical functional connections in frontal lobe epilepsy: A resting-state fMRI study.

    Science.gov (United States)

    Dong, Li; Wang, Pu; Peng, Rui; Jiang, Sisi; Klugah-Brown, Benjamin; Luo, Cheng; Yao, Dezhong

    2016-12-01

    The purpose of this study was to investigate alterations of basal ganglia-cortical functional connections in patients with frontal lobe epilepsy (FLE). Resting-state functional magnetic resonance imaging (fMRI) data were gathered from 19 FLE patients and 19 age- and gender-matched healthy controls. Functional connectivity (FC) analysis was used to assess the functional connections between basal ganglia and cerebral cortex. Regions of interest, including the left/right caudate, putamen, pallidum and thalamus, were selected as the seeds. Two sample t-test was used to determine the difference between patients and controls, while controlling the age, gender and head motions. Compared with controls, FLE patients demonstrated increased FCs between basal ganglia and regions including the right fusiform gyrus, the bilateral cingulate gyrus, the precuneus and anterior cingulate gyrus. Reduced FCs were mainly located in a range of brain regions including the bilateral middle occipital gyrus, the ventral frontal lobe, the right putamen, the left fusiform gyrus and right rolandic operculum. In addition, the relationships between basal ganglia-cingulate connections and durations of epilepsy were also found. The alterations of functional integrity within the basal ganglia, as well as its connections to limbic and ventral frontal areas, indicate the important roles of the basal ganglia-cortical functional connections in FLE, and provide new insights in the pathophysiological mechanism of FLE. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Gustatory imagery reveals functional connectivity from the prefrontal to insular cortices traced with magnetoencephalography.

    Science.gov (United States)

    Kobayashi, Masayuki; Sasabe, Tetsuya; Shigihara, Yoshihito; Tanaka, Masaaki; Watanabe, Yasuyoshi

    2011-01-01

    Our experience and prejudice concerning food play an important role in modulating gustatory information processing; gustatory memory stored in the central nervous system influences gustatory information arising from the peripheral nervous system. We have elucidated the mechanism of the "top-down" modulation of taste perception in humans using functional magnetic resonance imaging (fMRI) and demonstrated that gustatory imagery is mediated by the prefrontal (PFC) and insular cortices (IC). However, the temporal order of activation of these brain regions during gustatory imagery is still an open issue. To explore the source of "top-down" signals during gustatory imagery tasks, we analyzed the temporal activation patterns of activated regions in the cerebral cortex using another non-invasive brain imaging technique, magnetoencephalography (MEG). Gustatory imagery tasks were presented by words (Letter G-V) or pictures (Picture G-V) of foods/beverages, and participants were requested to recall their taste. In the Letter G-V session, 7/9 (77.8%) participants showed activation in the IC with a latency of 401.7±34.7 ms (n = 7) from the onset of word exhibition. In 5/7 (71.4%) participants who exhibited IC activation, the PFC was activated prior to the IC at a latency of 315.2±56.5 ms (n = 5), which was significantly shorter than the latency to the IC activation. In the Picture G-V session, the IC was activated in 6/9 (66.7%) participants, and only 1/9 (11.1%) participants showed activation in the PFC. There was no significant dominance between the right and left IC or PFC during gustatory imagery. These results support those from our previous fMRI study in that the Letter G-V session rather than the Picture G-V session effectively activates the PFC and IC and strengthen the hypothesis that the PFC mediates "top-down" control of retrieving gustatory information from the storage of long-term memories and in turn activates the IC.

  18. Spinal Cord Stimulation (SCS) and Functional Magnetic Resonance Imaging (fMRI): Modulation of Cortical Connectivity With Therapeutic SCS.

    Science.gov (United States)

    Deogaonkar, Milind; Sharma, Mayur; Oluigbo, Chima; Nielson, Dylan M; Yang, Xiangyu; Vera-Portocarrero, Louis; Molnar, Gregory F; Abduljalil, Amir; Sederberg, Per B; Knopp, Michael; Rezai, Ali R

    2016-02-01

    The neurophysiological basis of pain relief due to spinal cord stimulation (SCS) and the related cortical processing of sensory information are not completely understood. The aim of this study was to use resting state functional magnetic resonance imaging (rs-fMRI) to detect changes in cortical networks and cortical processing related to the stimulator-induced pain relief. Ten patients with complex regional pain syndrome (CRPS) or neuropathic leg pain underwent thoracic epidural spinal cord stimulator implantation. Stimulation parameters associated with "optimal" pain reduction were evaluated prior to imaging studies. Rs-fMRI was obtained on a 3 Tesla, Philips Achieva MRI. Rs-fMRI was performed with stimulator off (300TRs) and stimulator at optimum (Opt, 300 TRs) pain relief settings. Seed-based analysis of the resting state functional connectivity was conducted using seeds in regions established as participating in pain networks or in the default mode network (DMN) in addition to the network analysis. NCUT (normalized cut) parcellation was used to generate 98 cortical and subcortical regions of interest in order to expand our analysis of changes in functional connections to the entire brain. We corrected for multiple comparisons by limiting the false discovery rate to 5%. Significant differences in resting state connectivity between SCS off and optimal state were seen between several regions related to pain perception, including the left frontal insula, right primary and secondary somatosensory cortices, as well as in regions involved in the DMN, such as the precuneus. In examining changes in connectivity across the entire brain, we found decreased connection strength between somatosensory and limbic areas and increased connection strength between somatosensory and DMN with optimal SCS resulting in pain relief. This suggests that pain relief from SCS may be reducing negative emotional processing associated with pain, allowing somatosensory areas to become more

  19. Estimation of Directed Effective Connectivity from fMRI Functional Connectivity Hints at Asymmetries of Cortical Connectome.

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    Matthieu Gilson

    2016-03-01

    Full Text Available The brain exhibits complex spatio-temporal patterns of activity. This phenomenon is governed by an interplay between the internal neural dynamics of cortical areas and their connectivity. Uncovering this complex relationship has raised much interest, both for theory and the interpretation of experimental data (e.g., fMRI recordings using dynamical models. Here we focus on the so-called inverse problem: the inference of network parameters in a cortical model to reproduce empirically observed activity. Although it has received a lot of interest, recovering directed connectivity for large networks has been rather unsuccessful so far. The present study specifically addresses this point for a noise-diffusion network model. We develop a Lyapunov optimization that iteratively tunes the network connectivity in order to reproduce second-order moments of the node activity, or functional connectivity. We show theoretically and numerically that the use of covariances with both zero and non-zero time shifts is the key to infer directed connectivity. The first main theoretical finding is that an accurate estimation of the underlying network connectivity requires that the time shift for covariances is matched with the time constant of the dynamical system. In addition to the network connectivity, we also adjust the intrinsic noise received by each network node. The framework is applied to experimental fMRI data recorded for subjects at rest. Diffusion-weighted MRI data provide an estimate of anatomical connections, which is incorporated to constrain the cortical model. The empirical covariance structure is reproduced faithfully, especially its temporal component (i.e., time-shifted covariances in addition to the spatial component that is usually the focus of studies. We find that the cortical interactions, referred to as effective connectivity, in the tuned model are not reciprocal. In particular, hubs are either receptors or feeders: they do not exhibit both

  20. Relationships Between Altered Functional Magnetic Resonance Imaging Activation and Cortical Thickness in Patients With Euthymic Bipolar I Disorder.

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    Joshi, Shantanu H; Vizueta, Nathalie; Foland-Ross, Lara; Townsend, Jennifer D; Bookheimer, Susan Y; Thompson, Paul M; Narr, Katherine L; Altshuler, Lori L

    2016-11-01

    Performance during cognitive control functional magnetic resonance imaging (fMRI) tasks are associated with frontal lobe hypoactivation in patients with bipolar disorder, even while euthymic. Here, we study the structural underpinnings for this functional abnormality simultaneously with brain activation data. In a sample of ninety adults (45 with inter-episode Bipolar I disorder and 45 healthy controls), we explored whether abnormal functional activation patterns in bipolar euthymic subjects during a Go-NoGo fMRI task are associated with regional deficits in cortical gray matter thickness in the same regions. Cross-sectional differences in fMRI activation were used to form a-priori hypotheses for region-of-interest cortical gray matter thickness analyses. fMRI BOLD to structural magnetic resonance imaging (sMRI) thickness correlations were conducted across the sample and within patients and controls separately. During response inhibition (NoGo minus Go), bipolar subjects showed significant hypoactivation and reduced thickness in the inferior frontal cortex (IFC), superior frontal gyrus and cingulate compared to controls. Cingulate hypoactivation corresponded with reduced regional thickness. A significant activation by disease state interaction was observed with thickness in left prefrontal areas. Reduced cingulate fMRI activation is associated with reduced cortical thickness. In the left frontal lobe, a thinner cortex was associated with increased fMRI activation in patients, but showed a reverse trend in controls. These findings suggest that reduced activation in the IFC and cingulate during a response inhibition task may have an underlying structural etiology, which may explain task-related functional hypoactivation that persists even when patients are euthymic.

  1. Cortical Map Plasticity as a Function of Vagus Nerve Stimulation Intensity.

    Science.gov (United States)

    Borland, M S; Vrana, W A; Moreno, N A; Fogarty, E A; Buell, E P; Sharma, P; Engineer, C T; Kilgard, M P

    2016-01-01

    Pairing sensory or motor events with vagus nerve stimulation (VNS) can reorganize sensory or motor cortex. Repeatedly pairing a tone with a brief period of VNS increases the proportion of primary auditory cortex (A1) responding to the frequency of the paired tone. However, the relationship between VNS intensity and cortical map plasticity is not known. The primary goal of this study was to determine the range of VNS intensities that can be used to direct cortical map plasticity. The rats were exposed to a 9 kHz tone paired with VNS at intensities of 0.4, 0.8, 1.2, or 1.6 mA. In rats that received moderate (0.4-0.8 mA) intensity VNS, 75% more cortical neurons were tuned to frequencies near the paired tone frequency. A two-fold effective range is broader than expected based on previous VNS studies. Rats that received high (1.2-1.6 mA) intensity VNS had significantly fewer neurons tuned to the same frequency range compared to the moderate intensity group. This result is consistent with previous results documenting that VNS is memory enhancing as a non-monotonic relationship of VNS intensity. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Drosophila Mtm and class II PI3K coregulate a PI(3)P pool with cortical and endolysosomal functions.

    Science.gov (United States)

    Velichkova, Michaella; Juan, Joe; Kadandale, Pavan; Jean, Steve; Ribeiro, Inês; Raman, Vignesh; Stefan, Chris; Kiger, Amy A

    2010-08-09

    Reversible phosphoinositide phosphorylation provides a dynamic membrane code that balances opposing cell functions. However, in vivo regulatory relationships between specific kinases, phosphatases, and phosphoinositide subpools are not clear. We identified myotubularin (mtm), a Drosophila melanogaster MTM1/MTMR2 phosphoinositide phosphatase, as necessary and sufficient for immune cell protrusion formation and recruitment to wounds. Mtm-mediated turnover of endosomal phosphatidylinositol 3-phosphate (PI(3)P) pools generated by both class II and III phosphatidylinositol 3-kinases (Pi3K68D and Vps34, respectively) is needed to down-regulate membrane influx, promote efflux, and maintain endolysosomal homeostasis. Endocytosis, but not endolysosomal size, contributes to cortical remodeling by mtm function. We propose that Mtm-dependent regulation of an endosomal PI(3)P pool has separable consequences for endolysosomal homeostasis and cortical remodeling. Pi3K68D depletion (but not Vps34) rescues protrusion and distribution defects in mtm-deficient immune cells and restores functions in other tissues essential for viability. The broad interactions between mtm and class II Pi3K68D suggest a novel strategy for rebalancing PI(3)P-mediated cell functions in MTM-related human disease.

  3. Alterations in the limbic/paralimbic cortices of Parkinson's disease patients with hyposmia under resting-state functional MRI by regional homogeneity and functional connectivity analysis.

    Science.gov (United States)

    Su, Meilan; Wang, Song; Fang, Weidong; Zhu, Yingcheng; Li, Rong; Sheng, Ke; Zou, Dezhi; Han, Yu; Wang, Xuefeng; Cheng, Oumei

    2015-07-01

    Hyposmia is a cardinal early symptom of Parkinson's disease (PD), but the pathophysiological mechanisms underlying it remain unclear. Resting-state functional MRI (RS-fMRI) demonstrates spontaneous neuronal activity. We hypothesized that there would be alterations in the olfaction-related regions of the limbic/paralimbic cortices in PD patients with obvious hyposmia by RS-fMRI. We used the "Five Odors for Olfactory Detection Arrays" to test the threshold of olfactory detection (TOD) for 54 PD patients and 22 age-matched controls. Using the mean TOD of the control group, patients were subdivided into two groups: PD with obvious hyposmia (OH-PD, n = 38) and PD with none/less obvious hyposmia (NOH-PD, n = 16). The regional brain activity of all subjects was investigated using RS-fMRI, in combination with regional homogeneity (ReHo) and functional connectivity (FC) analysis. There were different ReHo values in the limbic/paralimbic cortices between the OH-PD and NOH-PD groups. ReHo was significantly decreased in OH-PD patients in parts of the traditional olfactory regions (e.g. the amygdala, olfactory gyrus, orbital frontal cortex, parahippocampal gyrus and insula) and some non-traditional olfactory centers (e.g. the rectal gyrus and superior temporal pole), while increased in the left anterior/posterior cingulate cortex. FC analysis revealed decreased functional connectivity within the limbic/paralimbic cortices, especially in regions with reduced ReHo in the OH-PD group. PD with hyposmia is related to altered functional activity not only in the traditional olfactory center, but also in some non-traditional olfactory regions of the limbic/paralimbic cortices. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Presurgical language mapping in children with epilepsy: clinical usefulness of functional magnetic resonance imaging for the planning of cortical stimulation.

    Science.gov (United States)

    de Ribaupierre, Sandrine; Fohlen, Martine; Bulteau, Christine; Dorfmüller, Georg; Delalande, Olivier; Dulac, Olivier; Chiron, Catherine; Hertz-Pannier, Lucie

    2012-01-01

    Presurgical language mapping in dominant hemisphere epilepsy to evaluate the risk of postoperative deficit is particularly difficult in children. Extraoperative invasive cortical stimulation can show some areas critical to language, but not all of them, due to scarce sampling, poor cooperation, cortical immaturity, or network reorganization, whereas functional magnetic resonance imaging (fMRI) displays entire networks involved in, but not necessarily critical to, language. In a homogeneous series of children with epilepsy, we compared the contributions of language fMRI and depth electrode stimulations to optimize language mapping. Eight children (7.5-15.5 years) with left frontal or temporal epilepsy underwent language fMRI and language stimulation with depth electrodes as part of their comprehensive presurgical workup. fMRI data collected during sentence generation were analyzed using statistical parametric mapping (SPM2) (false discovery rate [FDR] p Bipolar stimulations were performed during language production tasks. By coregistering fMRI and postimplantation computed tomography (CT) images, we were able to directly compare the cortical areas identified by both investigations. fMRI during sentence generation robustly showed activation in the whole perisylvian regions with little reorganization (left hemisphere dominant in 7). Of the 184 electrode contacts tested for language, only 8 were positive (language disruption) in three of the seven patients with periictal language impairment and left language dominance. All of the positive contacts colocalized with an fMRI activated cluster, that is, fMRI did not miss any region critical to language (sensitivity = 100%). However, 54 of the 176 negative contacts were within activated clusters (low specificity). In children with epilepsy, the sensitivity of fMRI during sentence generation allows for the detection of all critical regions displayed by cortical stimulation within the large perisylvian language network, but

  5. Altered levels of the splicing factor muscleblind modifies cerebral cortical function in mouse models of myotonic dystrophy.

    Science.gov (United States)

    Chen, Gang; Carter, Russell E; Cleary, John D; Reid, Tammy S; Ranum, Laura P; Swanson, Maurice S; Ebner, Timothy J

    2018-01-10

    Myotonic dystrophy (DM) is a progressive, multisystem disorder affecting skeletal muscle, heart, and central nervous system. In both DM1 and DM2, microsatellite expansions of CUG and CCUG RNA repeats, respectively, accumulate and disrupt functions of alternative splicing factors, including muscleblind (MBNL) proteins. Grey matter loss and white matter changes, including the corpus callosum, likely underlie cognitive and executive function deficits in DM patients. However, little is known how cerebral cortical circuitry changes in DM. Here, flavoprotein optical imaging was used to assess local and contralateral responses to intracortical motor cortex stimulation in DM-related mouse models. In control mice, brief train stimulation generated ipsilateral and contralateral homotopic fluorescence increases, the latter mediated by the corpus callosum. Single pulse stimulation produced an excitatory response with an inhibitory-like surround response mediated by GABAA receptors. In a mouse model of DM2 (Mbnl2 KO), we observed prolonged and increased responsiveness to train stimulation and loss of the inhibition from single pulse stimulation. Conversely, mice overexpressing human MBNL1 (MBNL1-OE) exhibited decreased contralateral response to train stimulation and reduction of inhibitory-like surround to single pulse stimulation. Therefore, altering levels of two key DM-associated splicing factors modifies functions of local cortical circuits and contralateral responses mediated through the corpus callosum. Copyright © 2018. Published by Elsevier Inc.

  6. Routes of Motivation: Stable Psychological Dispositions Are Associated with Dynamic Changes in Cortico-Cortical Functional Connectivity

    Science.gov (United States)

    Viola, Vanda; Tosoni, Annalisa; Kruglanski, Arie W.; Galati, Gaspare; Mannetti, Lucia

    2014-01-01

    The present study provides a neurobiological framework to the theory of epistemic motivation that has been extensively studied for the last three decades in the domain of social cognition. Epistemic motivations affect the way people generate and validate hypotheses, and ultimately form and modify knowledge. Strong dispositional measures such as need for cognitive closure (NCC), the desire for a quick firm answer (any answer) to a question, show gross and stable inter-individual differences. The cognitive mechanisms and neural underpinnings of such differences, however, remain largely unexplored. Here we show that high (compared to low) levels of NCC, measured with need for cognitive closure scale, are associated with reduced online adjustment in cognitive control, as indexed by behavioral conflict adaptation. This behavioral effect is mediated by dynamic changes in cortico-cortical functional connectivity between prefrontal regions involved in conflict monitoring and implementation of cognitive control. In particular, these regions show increased functional connectivity after exposure to conflict in low but not high NCC individuals. These results demonstrate that the level of flexibility of functional cortico-cortical connections can mediate stable psychological dispositions. PMID:24892718

  7. Domiciliary VR-Based Therapy for Functional Recovery and Cortical Reorganization: Randomized Controlled Trial in Participants at the Chronic Stage Post Stroke

    OpenAIRE

    Ballester, Bel?n Rubio; Nirme, Jens; Camacho, Irene; Duarte, Esther; Rodr?guez, Susana; Cuxart, Ampar; Duff, Armin; Paul F M J Verschure

    2017-01-01

    Background Most stroke survivors continue to experience motor impairments even after hospital discharge. Virtual reality-based techniques have shown potential for rehabilitative training of these motor impairments. Here we assess the impact of at-home VR-based motor training on functional motor recovery, corticospinal excitability and cortical reorganization. Objective The aim of this study was to identify the effects of home-based VR-based motor rehabilitation on (1) cortical reorganization,...

  8. Turing-like structures in a functional model of cortical spreading depression

    Science.gov (United States)

    Verisokin, A. Yu.; Verveyko, D. V.; Postnov, D. E.

    2017-12-01

    Cortical spreading depression (CSD) along with migraine waves and spreading depolarization events with stroke or injures are the front-line examples of extreme physiological behaviors of the brain cortex which manifest themselves via the onset and spreading of localized areas of neuronal hyperactivity followed by their depression. While much is known about the physiological pathways involved, the dynamical mechanisms of the formation and evolution of complex spatiotemporal patterns during CSD are still poorly understood, in spite of the number of modeling studies that have been already performed. Recently we have proposed a relatively simple mathematical model of cortical spreading depression which counts the effects of neurovascular coupling and cerebral blood flow redistribution during CSD. In the present study, we address the main dynamical consequences of newly included pathways, namely, the changes in the formation and propagation speed of the CSD front and the pattern formation features in two dimensions. Our most notable finding is that the combination of vascular-mediated spatial coupling with local regulatory mechanisms results in the formation of stationary Turing-like patterns during a CSD event.

  9. Cortical networks for working memory and executive functions sustain the conscious resting state in man.

    Science.gov (United States)

    Mazoyer, B; Zago, L; Mellet, E; Bricogne, S; Etard, O; Houdé, O; Crivello, F; Joliot, M; Petit, L; Tzourio-Mazoyer, N

    2001-02-01

    The cortical anatomy of the conscious resting state (REST) was investigated using a meta-analysis of nine positron emission tomography (PET) activation protocols that dealt with different cognitive tasks but shared REST as a common control state. During REST, subjects were in darkness and silence, and were instructed to relax, refrain from moving, and avoid systematic thoughts. Each protocol contrasted REST to a different cognitive task consisting either of language, mental imagery, mental calculation, reasoning, finger movement, or spatial working memory, using either auditory, visual or no stimulus delivery, and requiring either vocal, motor or no output. A total of 63 subjects and 370 spatially normalized PET scans were entered in the meta-analysis. Conjunction analysis revealed a network of brain areas jointly activated during conscious REST as compared to the nine cognitive tasks, including the bilateral angular gyrus, the left anterior precuneus and posterior cingulate cortex, the left medial frontal and anterior cingulate cortex, the left superior and medial frontal sulcus, and the left inferior frontal cortex. These results suggest that brain activity during conscious REST is sustained by a large scale network of heteromodal associative parietal and frontal cortical areas, that can be further hierarchically organized in an episodic working memory parieto-frontal network, driven in part by emotions, working under the supervision of an executive left prefrontal network.

  10. Discontinuous Galerkin finite element method for solving population density functions of cortical pyramidal and thalamic neuronal populations.

    Science.gov (United States)

    Huang, Chih-Hsu; Lin, Chou-Ching K; Ju, Ming-Shaung

    2015-02-01

    Compared with the Monte Carlo method, the population density method is efficient for modeling collective dynamics of neuronal populations in human brain. In this method, a population density function describes the probabilistic distribution of states of all neurons in the population and it is governed by a hyperbolic partial differential equation. In the past, the problem was mainly solved by using the finite difference method. In a previous study, a continuous Galerkin finite element method was found better than the finite difference method for solving the hyperbolic partial differential equation; however, the population density function often has discontinuity and both methods suffer from a numerical stability problem. The goal of this study is to improve the numerical stability of the solution using discontinuous Galerkin finite element method. To test the performance of the new approach, interaction of a population of cortical pyramidal neurons and a population of thalamic neurons was simulated. The numerical results showed good agreement between results of discontinuous Galerkin finite element and Monte Carlo methods. The convergence and accuracy of the solutions are excellent. The numerical stability problem could be resolved using the discontinuous Galerkin finite element method which has total-variation-diminishing property. The efficient approach will be employed to simulate the electroencephalogram or dynamics of thalamocortical network which involves three populations, namely, thalamic reticular neurons, thalamocortical neurons and cortical pyramidal neurons. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Optimized gamma synchronization enhances functional binding of fronto-parietal cortices in mathematically gifted adolescents during deductive reasoning

    Directory of Open Access Journals (Sweden)

    Li eZhang

    2014-06-01

    Full Text Available As enhanced fronto-parietal network has been suggested to support reasoning ability of math-gifted adolescents, the main goal of this EEG source analysis is to investigate the temporal binding of the gamma-band (30-60Hz synchronization between frontal and parietal cortices in adolescents with exceptional mathematical ability, including the functional connectivity of gamma neurocognitive network, the temporal dynamics of fronto-parietal network (phase-locking durations and network lability in time domain, and the self-organized criticality of synchronizing oscillation. Compared with the average-ability subjects, the math-gifted adolescents show a highly integrated fronto-parietal network due to distant gamma phase-locking oscillations, which is indicated by lower modularity of the global network topology, more connector bridges between the frontal and parietal cortices and less connector hubs in the sensorimotor cortex. The time-domain analysis finds that, while maintaining more stable phase dynamics of the fronto-parietal coupling, the math-gifted adolescents are characterized by more extensive fronto-parietal connection reconfiguration. The results from sample fitting in the power-law model further find that the phase-locking durations in the math-gifted brain abides by a wider interval of the power-law distribution. This phase-lock distribution mechanism could represent a relatively optimized pattern for the functional binding of frontal-parietal network, which underlies stable fronto-parietal connectivity and increases flexibility of timely network reconfiguration.

  12. Aided cortical response, speech intelligibility, consonant perception and functional performance of young children using conventional amplification or nonlinear frequency compression.

    Science.gov (United States)

    Zhang, Vicky W; Ching, Teresa Y C; Van Buynder, Patricia; Hou, Sanna; Flynn, Christopher; Burns, Lauren; McGhie, Karen; Wong, Angela O C

    2014-10-01

    The aim of this study was to compare conventional processing with nonlinear frequency compression (NLFC) in hearing aids for young children with bilateral hearing loss. Sixty-four children aged between 2 and 7 years with bilateral hearing aids were recruited. Evaluations of cortical responses, speech intelligibility rating, consonant perception and functional performance were completed with the children wearing their personal hearing aids with conventional processing. The children were then refitted with new hearing aids with NLFC processing. Following a six-week familiarization period, they were evaluated again while using their hearing aids with NLFC activated. The mean speech intelligibility rating and the number of cortical responses present for /s/were significantly higher when children were using NLFC processing than conventional processing in their hearing aids (pspeech intelligibility and functional performance in real life by parents. On average, greater benefits from NLFC processing was associated with poorer hearing at 4 kHz. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  13. Cortical mechanics and myosin-II abnormalities associated with post-ovulatory aging: implications for functional defects in aged eggs

    Science.gov (United States)

    Mackenzie, Amelia C.L.; Kyle, Diane D.; McGinnis, Lauren A.; Lee, Hyo J.; Aldana, Nathalia; Robinson, Douglas N.; Evans, Janice P.

    2016-01-01

    STUDY HYPOTHESIS Cellular aging of the egg following ovulation, also known as post-ovulatory aging, is associated with aberrant cortical mechanics and actomyosin cytoskeleton functions. STUDY FINDING Post-ovulatory aging is associated with dysfunction of non-muscle myosin-II, and pharmacologically induced myosin-II dysfunction produces some of the same deficiencies observed in aged eggs. WHAT IS KNOWN ALREADY Reproductive success is reduced with delayed fertilization and when copulation or insemination occurs at increased times after ovulation. Post-ovulatory aged eggs have several abnormalities in the plasma membrane and cortex, including reduced egg membrane receptivity to sperm, aberrant sperm-induced cortical remodeling and formation of fertilization cones at the site of sperm entry, and reduced ability to establish a membrane block to prevent polyspermic fertilization. STUDY DESIGN, SAMPLES/MATERIALS, METHODS Ovulated mouse eggs were collected at 21–22 h post-human chorionic gonadotrophin (hCG) (aged eggs) or at 13–14 h post-hCG (young eggs), or young eggs were treated with the myosin light chain kinase (MLCK) inhibitor ML-7, to test the hypothesis that disruption of myosin-II function could mimic some of the effects of post-ovulatory aging. Eggs were subjected to various analyses. Cytoskeletal proteins in eggs and parthenogenesis were assessed using fluorescence microscopy, with further analysis of cytoskeletal proteins in immunoblotting experiments. Cortical tension was measured through micropipette aspiration assays. Egg membrane receptivity to sperm was assessed in in vitro fertilization (IVF) assays. Membrane topography was examined by low-vacuum scanning electron microscopy (SEM). MAIN RESULTS AND THE ROLE OF CHANCE Aged eggs have decreased levels and abnormal localizations of phosphorylated myosin-II regulatory light chain (pMRLC; P = 0.0062). Cortical tension, which is mediated in part by myosin-II, is reduced in aged mouse eggs when compared with

  14. Social vulnerability and prefrontal cortical function in elderly people: a report from the Canadian Study of Health and Aging.

    Science.gov (United States)

    Andrew, Melissa K; Fisk, John D; Rockwood, Kenneth

    2011-04-01

    Prefrontal cortical lobe function is related to social behavior in humans. We investigated whether performance on tests of prefrontal cortical function was associated with social vulnerability. Associations with non-frontal cognitive function were investigated for comparison. 1216 participants aged 70+ of the Canadian Study of Health and Aging-2 screening examination, who also underwent detailed neuropsychological testing, comprised the study sample. Performance on WAIS-R abstraction, WAIS-R comprehension, Trails B, FAS and category verbal fluency, Block construction, Token Test and Wechsler Memory Scale Information Subset was tested in relation to the participant's level of social vulnerability using regression models adjusted for age, education, sex, frailty, MMSE score, diagnosis of depression, and use of psychoactive medications. Social vulnerability was measured by an index comprising many social problems or "deficits". The most socially vulnerable group had worse performance on FAS verbal fluency, generating 4.1 fewer words (95% CI: 1.8-6.4, psocially vulnerable group; those with intermediate social vulnerability generated 2.6 fewer words (95% CI: 0.4-4.8, p = 0.02). Social vulnerability was also associated, though less strongly, with category verbal fluency. The most socially vulnerable people had impaired performance on the Trails B, taking 37 seconds longer (95% CI: 11-63, p = 0.005). These results were independent of age, education, sex, frailty, MMSE score, depression, and psychoactive medications. Social vulnerability was not associated with performance on WAIS-R abstraction, WAIS-R comprehension, Block Design, Token Test or Wechsler Memory Scale tests. High social vulnerability was associated with impaired performance on verbal fluency and set shifting but not with common sense judgment, abstraction, long-term memory, constructional ability, or language comprehension. The association between social functioning and the cognitive functions subserved by

  15. A Functional Switch of NuRD Chromatin Remodeling Complex Subunits Regulates Mouse Cortical Development

    Directory of Open Access Journals (Sweden)

    Justyna Nitarska

    2016-11-01

    Full Text Available Histone modifications and chromatin remodeling represent universal mechanisms by which cells adapt their transcriptional response to rapidly changing environmental conditions. Extensive chromatin remodeling takes place during neuronal development, allowing the transition of pluripotent cells into differentiated neurons. Here, we report that the NuRD complex, which couples ATP-dependent chromatin remodeling with histone deacetylase activity, regulates mouse brain development. Subunit exchange of CHDs, the core ATPase subunits of the NuRD complex, is required for distinct aspects of cortical development. Whereas CHD4 promotes the early proliferation of progenitors, CHD5 facilitates neuronal migration and CHD3 ensures proper layer specification. Inhibition of each CHD leads to defects of neuronal differentiation and migration, which cannot be rescued by expressing heterologous CHDs. Finally, we demonstrate that NuRD complexes containing specific CHDs are recruited to regulatory elements and modulate the expression of genes essential for brain development.

  16. When function mirrors structure: how slow waves are shaped by cortical layers

    Directory of Open Access Journals (Sweden)

    Cristiano Capone

    2015-04-01

    As the model predicted, we found that strips of early wave propagation reliably overlapped with the regions where maximum Up state duration and firing activity occurred, strengthening the duality between spontaneous activity and network structure. Finally, we matched the excitable strips with the slice cortical layers as identified by histology, finding a reliable overlap between such strips and L4 and L5 (see Figure 1E. Figure 1. A. Wavefronts for 2 modes of propagation. B. Average strips where wavefronts propagate earlier (black, and where Up states have maximum duration (green and magnitude (blue. C. Modulation of the connectivity parameter in the model. D. Nullclines under mean-field approximation varying levels of connectivity.  and C are average firing rate and fatigue level, respectively. Circles, fixed points. Dark to light gray, different excitability levels as in C, respectively. E. Example match between strip of early wave propagation and slice’s layers.

  17. Cortical brain connectivity evaluated by graph theory in dementia: a correlation study between functional and structural data.

    Science.gov (United States)

    Vecchio, Fabrizio; Miraglia, Francesca; Curcio, Giuseppe; Altavilla, Riccardo; Scrascia, Federica; Giambattistelli, Federica; Quattrocchi, Carlo Cosimo; Bramanti, Placido; Vernieri, Fabrizio; Rossini, Paolo Maria

    2015-01-01

    A relatively new approach to brain function in neuroscience is the "functional connectivity", namely the synchrony in time of activity in anatomically-distinct but functionally-collaborating brain regions. On the other hand, diffusion tensor imaging (DTI) is a recently developed magnetic resonance imaging (MRI)-based technique with the capability to detect brain structural connection with fractional anisotropy (FA) identification. FA decrease has been observed in the corpus callosum of subjects with Alzheimer's disease (AD) and mild cognitive impairment (MCI, an AD prodromal stage). Corpus callosum splenium DTI abnormalities are thought to be associated with functional disconnections among cortical areas. This study aimed to investigate possible correlations between structural damage, measured by MRI-DTI, and functional abnormalities of brain integration, measured by characteristic path length detected in resting state EEG source activity (40 participants: 9 healthy controls, 10 MCI, 10 mild AD, 11 moderate AD). For each subject, undirected and weighted brain network was built to evaluate graph core measures. eLORETA lagged linear connectivity values were used as weight of the edges of the network. Results showed that callosal FA reduction is associated to a loss of brain interhemispheric functional connectivity characterized by increased delta and decreased alpha path length. These findings suggest that "global" (average network shortest path length representing an index of how efficient is the information transfer between two parts of the network) functional measure can reflect the reduction of fiber connecting the two hemispheres as revealed by DTI analysis and also anticipate in time this structural loss.

  18. The PPAR-gamma agonist pioglitazone protects cortical neurons from inflammatory mediators via improvement in peroxisomal function

    Directory of Open Access Journals (Sweden)

    Gray Elizabeth

    2012-04-01

    Full Text Available Abstract Background Inflammation is known to play a pivotal role in mediating neuronal damage and axonal injury in a variety of neurodegenerative disorders. Among the range of inflammatory mediators, nitric oxide and hydrogen peroxide are potent neurotoxic agents. Recent evidence has suggested that oligodendrocyte peroxisomes may play an important role in protecting neurons from inflammatory damage. Methods To assess the influence of peroxisomal activation on nitric oxide mediated neurotoxicity, we investigated the effects of the peroxisomal proliferator activated receptor (PPAR gamma agonist, pioglitazone in primary cortical neurons that were either exposed to a nitric oxide donor or co-cultured with activated microglia. Results Pioglitazone protected neurons and axons against both nitric-oxide donor-induced and microglia-derived nitric oxide-induced toxicity. Moreover, cortical neurons treated with this compound showed a significant increase in the protein and gene expression of PPAR-gamma, which was associated with a concomitant increase in the enzymatic activity of catalase. In addition, the protection of neurons and axons against hydrogen peroxide-induced toxicity afforded by pioglitazone appeared to be dependent on catalase. Conclusions Collectively, these observations provide evidence that modulation of PPAR-gamma activity and peroxisomal function by pioglitazone attenuates both NO and hydrogen peroxide-mediated neuronal and axonal damage suggesting a new therapeutic approach to protect against neurodegenerative changes associated with neuroinflammation.

  19. Functional near-infrared spectroscopy maps cortical plasticity underlying altered motor performance induced by transcranial direct current stimulation.

    Science.gov (United States)

    Khan, Bilal; Hodics, Timea; Hervey, Nathan; Kondraske, George; Stowe, Ann M; Alexandrakis, George

    2013-11-01

    Transcranial direct current stimulation (tDCS) of the human sensorimotor cortex during physical rehabilitation induces plasticity in the injured brain that improves motor performance. Bi-hemispheric tDCS is a noninvasive technique that modulates cortical activation by delivering weak current through a pair of anodal-cathodal (excitation-suppression) electrodes, placed on the scalp and centered over the primary motor cortex of each hemisphere. To quantify tDCS-induced plasticity during motor performance, sensorimotor cortical activity was mapped during an event-related, wrist flexion task by functional near-infrared spectroscopy (fNIRS) before, during, and after applying both possible bi-hemispheric tDCS montages in eight healthy adults. Additionally, torque applied to a lever device during isometric wrist flexion and surface electromyography measurements of major muscle group activity in both arms were acquired concurrently with fNIRS. This multiparameter approach found that hemispheric suppression contralateral to wrist flexion changed resting-state connectivity from intra-hemispheric to inter-hemispheric and increased flexion speed (pincreased opposing muscle output resulting in a decrease in speed but an increase in accuracy (p<0.05 for both). The findings of this work suggest that tDCS with fNIRS and concurrent multimotor measurements can provide insights into how neuroplasticity changes muscle output, which could find future use in guiding motor rehabilitation.

  20. Altered Cortical Dynamics and Cognitive Function upon Haploinsufficiency of the Autism-Linked Excitatory Synaptic Suppressor MDGA2.

    Science.gov (United States)

    Connor, Steven A; Ammendrup-Johnsen, Ina; Chan, Allen W; Kishimoto, Yasushi; Murayama, Chiaki; Kurihara, Naokazu; Tada, Atsushi; Ge, Yuan; Lu, Hong; Yan, Ryan; LeDue, Jeffrey M; Matsumoto, Hirotaka; Kiyonari, Hiroshi; Kirino, Yutaka; Matsuzaki, Fumio; Suzuki, Toshiharu; Murphy, Timothy H; Wang, Yu Tian; Yamamoto, Tohru; Craig, Ann Marie

    2016-09-07

    Mutations in a synaptic organizing pathway contribute to autism. Autism-associated mutations in MDGA2 (MAM domain containing glycosylphosphatidylinositol anchor 2) are thought to reduce excitatory/inhibitory transmission. However, we show that mutation of Mdga2 elevates excitatory transmission, and that MDGA2 blocks neuroligin-1 interaction with neurexins and suppresses excitatory synapse development. Mdga2(+/-) mice, modeling autism mutations, demonstrated increased asymmetric synapse density, mEPSC frequency and amplitude, and altered LTP, with no change in measures of inhibitory synapses. Behavioral assays revealed an autism-like phenotype including stereotypy, aberrant social interactions, and impaired memory. In vivo voltage-sensitive dye imaging, facilitating comparison with fMRI studies in autism, revealed widespread increases in cortical spontaneous activity and intracortical functional connectivity. These results suggest that mutations in MDGA2 contribute to altered cortical processing through the dual disadvantages of elevated excitation and hyperconnectivity, and indicate that perturbations of the NRXN-NLGN pathway in either direction from the norm increase risk for autism. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Atrofia cortical posterior

    OpenAIRE

    Delgado D,Carolina; Donoso S,Archibaldo

    2009-01-01

    Posterior cortical atrophy (PCA) is a neurodegenerative syndrome, usually due to Alzheimer's disease. The first symptoms are progressive impairment of visuo spatial (Balint's and Gertsmann's syndromes) or visuo perceptive (visual agnosia, alexia) function. Episodic memory and executive function are spared until later stages. We report two males aged 51 and 55years and three females aged 50, 54 and 56 years, with posterior cortical atrophy. Ophthalmologic study was normal in all. Presenting si...

  2. Attenuation of cortical activity triggering descending pain inhibition in chronic low back pain patients: a functional magnetic resonance imaging study.

    Science.gov (United States)

    Matsuo, Yohei; Kurata, Jiro; Sekiguchi, Miho; Yoshida, Katsuhiro; Nikaido, Takuya; Konno, Shin-Ichi

    2017-08-01

    A considerable portion of chronic low back pain (cLBP) patients lack anatomical abnormality, resist conventional therapeutic interventions, and their symptoms are often complicated with psychological and social factors. Such patients have been reported to show cerebral abnormalities both in anatomy and function by neuroimaging studies. Here we examined differences in cerebral reactivity to a simulated low back pain stimulus between cLBP patients and healthy controls by functional magnetic resonance imaging (fMRI), and their behavioral correlates from a psychophysical questionnaire. Eleven cLBP patients and 13 healthy subjects (HS) were enrolled in this study. After psychophysical evaluation on-going pain with McGill Pain Questionnaire Short Form (MPQ), they underwent whole-brain fMRI in a 3-Tesla MRI scanner while receiving three blocks of 30-s mechanical pain stimuli at the left low back with a 30-s rest in between, followed by a three-dimensional anatomical imaging. Functional images were analyzed with a multi-subject general linear model for blood oxygenation level-dependent (BOLD) signal changes associated with pain. Individual BOLD signal amplitudes at activated clusters were examined for correlation with psychophysical variables. Two in the cLBP and five data sets in the HS groups were excluded from analysis because of deficient or artifactual data or mismatch in age. The HS group showed LBP-related activation at the right insular cortex, right dorsolateral prefrontal cortex (DLPFC), left anterior cingulate cortex (ACC), and left precuneus; and deactivation in a large area over the parietal and occipital cortices, including the bilateral superior parietal cortex. On the other hand, the cLBP group did not show any significant activation at those cortical areas, but showed similar deactivation at the bilateral superior parietal cortex and part of the premotor area. An HS > cLBP contrast revealed significantly less activity at the ACC and DLPFC in the c

  3. Neuronal Correlates of Individual Differences in the Big Five Personality Traits: Evidences from Cortical Morphology and Functional Homogeneity.

    Science.gov (United States)

    Li, Ting; Yan, Xu; Li, Yuan; Wang, Junjie; Li, Qiang; Li, Hong; Li, Junfeng

    2017-01-01

    There have been many neuroimaging studies of human personality traits, and it have already provided glimpse into the neurobiology of complex traits. And most of previous studies adopt voxel-based morphology (VBM) analysis to explore the brain-personality mechanism from two levels (vertex and regional based), the findings are mixed with great inconsistencies and the brain-personality relations are far from a full understanding. Here, we used a new method of surface-based morphology (SBM) analysis, which provides better alignment of cortical landmarks to generate about the associations between cortical morphology and the personality traits across 120 healthy individuals at both vertex and regional levels. While to further reveal local functional correlates of the morphology-personality relationships, we related surface-based functional homogeneity measures to the regions identified in the regional-based SBM correlation. Vertex-wise analysis revealed that people with high agreeableness exhibited larger areas in the left superior temporal gyrus. Based on regional parcellation we found that extroversion was negatively related with the volume of the left lateral occipito-temporal gyrus and agreeableness was negatively associated with the sulcus depth of the left superior parietal lobule. Moreover, increased regional homogeneity in the left lateral occipito-temporal gyrus is related to the scores of extroversion, and increased regional homogeneity in the left superior parietal lobule is related to the scores of agreeableness. These findings provide supporting evidence of a link between personality and brain structural mysteries with a method of SBM, and further suggest that local functional homogeneity of personality traits has neurobiological relevance that is likely based on anatomical substrates.

  4. Functional cortical reorganization after low-frequency repetitive transcranial magnetic stimulation plus intensive occupational therapy for upper limb hemiparesis: evaluation by functional magnetic resonance imaging in poststroke patients.

    Science.gov (United States)

    Yamada, Naoki; Kakuda, Wataru; Senoo, Atsushi; Kondo, Takahiro; Mitani, Sugao; Shimizu, Masato; Abo, Masahiro

    2013-08-01

    Low-frequency repetitive transcranial magnetic stimulation of the nonlesional hemisphere combined with occupational therapy significantly improves motor function of the affected upper limb in poststroke hemiparetic patients, but the recovery mechanism remains unclear. To investigate the recovery mechanism using functional magnetic resonance imaging. Forty-seven poststroke hemiparetic patients were hospitalized to receive 12 sessions of 40-min low-frequency repetitive transcranial magnetic stimulation over the nonlesional hemisphere and daily occupational therapy for 15 days. Motor function was evaluated with the Fugl-Meyer Assessment and Wolf Motor Function Test. The functional magnetic resonance imaging with motor tasks was performed at admission and discharge. The laterality index of activated voxel number in Brodmann areas 4 and 6 on functional magnetic resonance imaging was calculated (laterality index range of -1 to +1). Patients were divided into two groups based on functional magnetic resonance imaging findings before the intervention: group 1: patients who showed bilateral activation (n = 27); group 2: patients with unilateral activation (n = 20). Treatment resulted in improvement in Fugl-Meyer Assessment and Wolf Motor Function Test in the two groups (P functional magnetic resonance imaging indicated that our proposed treatment can induce functional cortical reorganization, leading to motor functional recovery of the affected upper limb. Especially, it seems that neural activation in the lesional hemisphere plays an important role in such recovery in poststroke hemiparetic patients. © 2013 The Authors. International Journal of Stroke © 2013 World Stroke Organization.

  5. The Effects of Acute and Chronic Ethanol Exposure on Presynaptic and Postsynaptic GABAA Receptor Function in Cultured Cortical and Hippocampal Neurons

    Science.gov (United States)

    Fleming, Rebekah L.; Manis, Paul B.; Morrow, A. Leslie

    2009-01-01

    Decades after ethanol was first described as a GABA mimetic, the precise mechanisms that produce the acute effects of ethanol and the physiological adaptations that underlie ethanol tolerance and dependence remain unclear. While a substantial body of evidence suggests that ethanol acts on GABAergic neurotransmission to enhance inhibition in the CNS, the precise mechanisms underlying the physiological effects of both acute and chronic ethanol exposure are still under investigation. We have used in vitro ethanol exposure followed by recording of miniature inhibitory postsynaptic currents (mIPSCs) to determine whether acute or chronic ethanol exposure directly alters synaptic GABAA receptor function or GABA release in cultured cortical and hippocampal neurons. Acute ethanol exposure slightly increased the duration of mIPSCs in hippocampal neurons but did not alter mIPSC kinetics in cortical neurons. Acute ethanol exposure did not change mIPSC frequency in either hippocampal or cortical neurons. One day of chronic ethanol exposure produced a transient decrease in mIPSC duration in cortical neurons but did not alter mIPSC kinetics in hippocampal neurons. Chronic ethanol exposure did not change mIPSC frequency in either hippocampal or cortical neurons. Chronic ethanol exposure also did not produce substantial cross-tolerance to a benzodiazepine in either hippocampal or cortical neurons. The results suggest that ethanol exposure in vitro has limited effects on synaptic GABAAR function and action-potential independent GABA release in cultured neurons and suggests that ethanol exposure in cultured cortical and hippocampal neurons may not reproduce all of the effects that occur in vivo and in acute brain slices. PMID:20004338

  6. Reciprocal Limbic-Cortical Function and Negative Mood: Converging PET Findings in Depression and Normal Sadness

    National Research Council Canada - National Science Library

    Mayberg, Helen S; Liotti, Mario; Brannan, Stephen K; McGinnis, Scott; Mahurin, Roderick K; Jerabek, Paul A; Silva, J. Arturo; Tekell, Janet L; Martin, Charles C; Lancaster, Jack L; Fox, Peter T

    1999-01-01

    .... Expanding on this theory, this study examined functional interactions between specific limbic and neocortical regions accompanying normal and disease-associated shifts in negative mood state. METHOD...

  7. The effects of a high-fat sucrose diet on functional outcome following cortical contusion injury in the rat.

    Science.gov (United States)

    Hoane, Michael R; Swan, Alicia A; Heck, Sarah E

    2011-09-30

    Traumatic brain injury (TBI) is a major public health issue affecting 1.7 million Americans each year, of which approximately 50,000 are fatal. High-fat sucrose (HFS) diets are another public health issue which can lead to obesity, hypertension, and many other debilitating disorders. These two disorders combined can lead to more complicated issues. It has recently been shown that HFS diets can reduce levels of brain-derived neurotrophic factor (BDNF) leading to reductions in neuronal and behavioral plasticity. This reduction in BDNF is suspected of increasing the susceptibility of the brain to injury. To test the effects of a HFS diet on recovery of function post-TBI, male Sprague-Dawley rats were used in this study. Eight weeks prior to TBI, rats were placed on a special HFS diet (n=14) or a standard rodent diet (n=14). Following this eight-week period, rats were prepared with bilateral frontal cortical contusion injuries (CCI) or sham procedures. Beginning two days post-TBI, animals were tested on a battery of behavioral tests to assess somatosensory dysfunction and spatial memory in the Morris water maze, with a reference memory and a working memory task. Following testing, animals were sacrificed and their brains processed for lesion analysis. The HFS diet worsened performance on the bilateral tactile adhesive removal test in sham animals. Injured animals on the Standard diet had a greater improvement in somatosensory performance in the adhesive removal test and had better performance on the working memory task compared to animals on the HFS diet. The HFS diet also resulted in significantly greater loss of cortical tissue post-CCI than in the Standard diet group. This study may aid in determining how nutritional characteristics or habits interact with damage to the brain. Copyright © 2011 Elsevier B.V. All rights reserved.

  8. Immediate cortical adaptation in visual and non-visual areas functions induced by monovision.

    Science.gov (United States)

    Zeri, Fabrizio; Berchicci, Marika; Naroo, Shehzad A; Pitzalis, Sabrina; Di Russo, Francesco

    2018-01-15

    Monovision is an optical correction for presbyopes that consists of correcting one eye for far distance and the other for near distance, creating a superimposition of an in-focus with a blurred image. Brain adaptation to monovision was studied in unexperienced observers by measuring visual evoked potentials from 64-channels. The first clear effect of monovision on visual evoked potentials was the C1 amplitude reduction, indicating that the unilateral blurring induced by monovision reduces feed-forward activity in primary visual area. Monovision led also to an increased amplitude of the P1 and pP1 components, with the latter originating in prefrontal regions. This effect probably works as an attentional compensatory activity used to compensate for the degraded V1 signal. A common and often successful option to correct presbyopia with contact lenses is monovision. This is an unbalanced correction across the two eyes where one eye is corrected for far vision and the other eye is corrected for near vision. Monovision is therefore a form of acquired anisometropia that causes a superimposition of an in-focus image with a blurred image. In spite of this visual anisometropia, monovision has been successfully used for many decadesl however the brain mechanism supporting monovision is not well understood. The present study aimed to measure the visual evoked potentials with a high-density electrode array (64-channel) in a group of presbyopes and to provide a detailed spatiotemporal analysis of the cortical activity after a short period of adaptation to monovision with contact lenses. When compared with a balanced eye near correction, monovision produced both a clear reduction of the earliest visual evoked potential components, the C1 and the N1, and an amplitude increase of the P1 and pP1. These results indicate that the unilateral blurring induced by wearing monovision contact lenses reduces feed-forward activity in the primary visual area and feedback activity in

  9. Autologous adult cortical cell transplantation enhances functional recovery following unilateral lesion of motor cortex in primates: a pilot study.

    Science.gov (United States)

    Kaeser, Mélanie; Brunet, Jean-François; Wyss, Alexander; Belhaj-Saif, Abderraouf; Liu, Yu; Hamadjida, Adjia; Rouiller, Eric M; Bloch, Jocelyne

    2011-05-01

    Although cell therapy is a promising approach after cerebral cortex lesion, few studies assess quantitatively its behavioral gain in nonhuman primates. Furthermore, implantations of fetal grafts of exogenous stem cells are limited by safety and ethical issues. To test in nonhuman primates the transplantation of autologous adult neural progenitor cortical cells with assessment of functional outcome. Seven adult macaque monkeys were trained to perform a manual dexterity task, before the hand representation in motor cortex was chemically lesioned unilaterally. Five monkeys were used as control, compared with 2 monkeys subjected to different autologous cells transplantation protocols performed at different time intervals. After lesion, there was a complete loss of manual dexterity in the contralesional hand. The 5 "control" monkeys recovered progressively and spontaneously part of their manual dexterity, reaching a unique and definitive plateau of recovery, ranging from 38% to 98% of prelesion score after 10 to 120 days. The 2 "treated" monkeys reached a first spontaneous recovery plateau at about 25 and 40 days postlesion, representing 35% and 61% of the prelesion performance, respectively. In contrast to the controls, a second recovery plateau took place 2 to 3 months after cell transplantation, corresponding to an additional enhancement of functional recovery, representing 24% and 37% improvement, respectively. These pilot data, derived from 2 monkeys treated differently, suggest that, in the present experimental conditions, autologous adult brain progenitor cell transplantation in a nonhuman primate is safe and promotes enhancement of functional recovery.

  10. No difference in frontal cortical activity during an executive functioning task after acute doses of aripiprazole and haloperidol

    Directory of Open Access Journals (Sweden)

    Ingeborg eBolstad

    2015-05-01

    Full Text Available Background: Aripiprazole is an atypical antipsychotic drug that is characterized by partial dopamine D2 receptor agonism. Its pharmacodynamic profile is proposed to be beneficial in the treatment of cognitive impairment, which is prevalent in psychotic disorders. This study compared brain activation characteristics produced by aripiprazole with that of haloperidol, a typical D2 receptor antagonist, during a task targeting executive functioning.Methods: Healthy participants received an acute oral dose of haloperidol, aripiprazole or placebo before performing an executive functioning task while blood-oxygen-level-dependent (BOLD functional magnetic resonance imaging (fMRI was carried out. Results: There was a tendency towards reduced performance in the aripiprazole group compared to the two other groups. The image analysis yielded a strong task-related BOLD-fMRI response within each group. An uncorrected between-group analysis showed that aripiprazole challenge resulted in stronger activation in the frontal and temporal gyri and the putamen compared with haloperidol challenge, but after correcting for multiple testing there was no significant group difference. Conclusion: No significant group differences between aripiprazole and haloperidol in frontal cortical activation were obtained when corrected for multiple comparisons.This study is registered in ClinicalTrials.gov (identifier: 2009-016222-14; https://clinicaltrials.gov/.

  11. Reduced functional connectivity between cortical sources in five meditation traditions detected with lagged coherence using EEG tomography.

    Science.gov (United States)

    Lehmann, Dietrich; Faber, Pascal L; Tei, Shisei; Pascual-Marqui, Roberto D; Milz, Patricia; Kochi, Kieko

    2012-04-02

    Brain functional states are established by functional connectivities between brain regions. In experienced meditators (13 Tibetan Buddhists, 15 QiGong, 14 Sahaja Yoga, 14 Ananda Marga Yoga, 15 Zen), 19-channel EEG was recorded before, during and after that meditation exercise which their respective tradition regards as route to the most desirable meditative state. The head surface EEG data were recomputed (sLORETA) into 19 cortical regional source model time series. All 171 functional connectivities between regions were computed as 'lagged coherence' for the eight EEG frequency bands (delta through gamma). This analysis removes ambiguities of localization, volume conduction-induced inflation of coherence, and reference-dependence. All significant differences (corrected for multiple testing) between meditation compared to no-task rest before and after meditation showed lower coherence during meditation, in all five traditions and eight (inhibitory as well as excitatory) frequency bands. Conventional coherence between the original head surface EEG time series very predominantly also showed reduced coherence during meditation. The topography of the functional connectivities was examined via PCA-based computation of principal connectivities. When going into and out of meditation, significantly different connectivities revealed clearly different topographies in the delta frequency band and minor differences in the beta-2 band. The globally reduced functional interdependence between brain regions in meditation suggests that interaction between the self process functions is minimized, and that constraints on the self process by other processes are minimized, thereby leading to the subjective experience of non-involvement, detachment and letting go, as well as of all-oneness and dissolution of ego borders during meditation. Copyright © 2011 Elsevier Inc. All rights reserved.

  12. Differentially disrupted functional connectivity in posteromedial cortical subregions in Alzheimer's disease.

    Science.gov (United States)

    Xia, Mingrui; Wang, Zhiqun; Dai, Zhengjia; Liang, Xia; Song, Haiqing; Shu, Ni; Li, Kuncheng; He, Yong

    2014-01-01

    Neuroimaging studies have demonstrated that patients with Alzheimer's disease (AD) have remarkable focal grey matter loss and hypometabolism in the posteromedial cortex (PMC), which is composed of the precuneus and posterior cingulate cortex, suggesting an important association of the PMC with AD pathophysiology. Studies have also shown that the PMC is a structurally and functionally heterogeneous structure containing various subregions with distinct connectivity profiles. However, whether these PMC subregions show differentially disrupted connectivity patterns in AD remains largely unknown. Here, we addressed this issue by collecting resting-state functional MRI data from 32 AD patients and 38 healthy controls. We automatically identified the PMC subregions using a graph-based module detection algorithm and then mapped the whole-brain functional connectivity pattern of each subregion. The functional connectivity analysis was followed by a hierarchical clustering analysis to classify each subregion. Three distinct spatial connectivity patterns were observed across the PMC subregions: the anterior dorsal zone was functionally connected with the sensorimotor cortex; the posterior dorsal zone was functionally connected with the frontoparietal cortex; and the central and ventral zones were functionally connected with the default-mode regions. Group comparison analysis revealed that all three functional systems were significantly disrupted in the AD patients compared to the controls and these disruptions were positively correlated with the patients' cognitive performance. Collectively, we showed that the subregions of the PMC exhibit differentially disrupted neuronal circuitry in AD patients, which provides new insight into the functional neuroanatomy of the human PMC and the alterations that may be relevant to disease.

  13. Cortical and Subcortical Coordination of Visual Spatial Attention Revealed by Simultaneous EEG-fMRI Recording.

    Science.gov (United States)

    Green, Jessica J; Boehler, Carsten N; Roberts, Kenneth C; Chen, Ling-Chia; Krebs, Ruth M; Song, Allen W; Woldorff, Marty G

    2017-08-16

    Visual spatial attention has been studied in humans with both electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) individually. However, due to the intrinsic limitations of each of these methods used alone, our understanding of the systems-level mechanisms underlying attentional control remains limited. Here, we examined trial-to-trial covariations of concurrently recorded EEG and fMRI in a cued visual spatial attention task in humans, which allowed delineation of both the generators and modulators of the cue-triggered event-related oscillatory brain activity underlying attentional control function. The fMRI activity in visual cortical regions contralateral to the cued direction of attention covaried positively with occipital gamma-band EEG, consistent with activation of cortical regions representing attended locations in space. In contrast, fMRI activity in ipsilateral visual cortical regions covaried inversely with occipital alpha-band oscillations, consistent with attention-related suppression of the irrelevant hemispace. Moreover, the pulvinar nucleus of the thalamus covaried with both of these spatially specific, attention-related, oscillatory EEG modulations. Because the pulvinar's neuroanatomical geometry makes it unlikely to be a direct generator of the scalp-recorded EEG, these covariational patterns appear to reflect the pulvinar's role as a regulatory control structure, sending spatially specific signals to modulate visual cortex excitability proactively. Together, these combined EEG/fMRI results illuminate the dynamically interacting cortical and subcortical processes underlying spatial attention, providing important insight not realizable using either method alone.SIGNIFICANCE STATEMENT Noninvasive recordings of changes in the brain's blood flow using functional magnetic resonance imaging and electrical activity using electroencephalography in humans have individually shown that shifting attention to a location in space

  14. Atypicalities in cortical structure, handedness, and functional lateralization for language in autism spectrum disorders.

    Science.gov (United States)

    Lindell, Annukka K; Hudry, Kristelle

    2013-09-01

    Language is typically a highly lateralized function, with atypically reduced or reversed lateralization linked to language impairments. Given the diagnostic and prognostic role of impaired language for autism spectrum disorders (ASDs), this paper reviews the growing body of literature that examines patterns of lateralization in individuals with ASDs. Including research from structural and functional imaging paradigms, and behavioral evidence from investigations of handedness, the review confirms that atypical lateralization is common in people with ASDs. The evidence indicates reduced structural asymmetry in fronto-temporal language regions, attenuated functional activation in response to language and pre-linguistic stimuli, and more ambiguous (mixed) hand preferences, in individuals with ASDs. Critically, the evidence emphasizes an intimate relationship between atypical lateralization and language impairment, with more atypical asymmetries linked to more substantive language impairment. Such evidence highlights opportunities for the identification of structural and functional biomarkers of ASDs, affording the potential for earlier diagnosis and intervention implementation.

  15. Reorganization of Functional Brain Maps After Exercise Training: Importance of Cerebellar-Thalamic-Cortical Pathway

    OpenAIRE

    Holschneider, DP; Yang, J; Guo, Y.; Maarek, J-M I

    2007-01-01

    Exercise training (ET) causes functional and morphologic changes in normal and injured brain. While studies have examined effects of short-term (same day) training on functional brain activation, less work has evaluated effects of long-term training, in particular treadmill running. An improved understanding is relevant as changes in neural reorganization typically require days to weeks, and treadmill training is a component of many neurorehabilitation programs.

  16. Transcranial Magnetic Stimulation: A Neuroscientific Probe of Cortical Function in Schizophrenia

    OpenAIRE

    McClintock, Shawn M.; Freitas, Catarina; Oberman, Lindsay; Lisanby, Sarah H.; Pascual-Leone, Alvaro

    2011-01-01

    Transcranial magnetic stimulation (TMS) is a neuropsychiatric tool that can serve as a useful method to better understand the neurobiology of cognitive function, behavior, and emotional processing. The purpose of this paper is to examine the utility of TMS as a means of measuring neocortical function in neuropsychiatric disorders in general, and schizophrenia in particular, for the Cognitive Neuroscience Treatment Research to Improve Cognition in Schizophrenia (CNTRICS) initiative. When incor...

  17. Anatomical coupling among distributed cortical regions in youth varies as a function of individual differences in vocabulary abilities.

    Science.gov (United States)

    Lee, Nancy Raitano; Raznahan, Armin; Wallace, Gregory L; Alexander-Bloch, Aaron; Clasen, Liv S; Lerch, Jason P; Giedd, Jay N

    2014-05-01

    Patient lesion and functional magnetic resonance imaging (fMRI) studies have provided convincing evidence that a distributed brain network subserves word knowledge. However, little is known about the structural correlates of this network within the context of typical development and whether anatomical coupling in linguistically relevant regions of cortex varies as a function of vocabulary skill. Here we investigate the association between vocabulary and anatomical coupling in 235 typically developing youth (ages 6-19 years) using structural MRI. The study's primary aim was to evaluate whether higher vocabulary performance was associated with greater vertex-level cortical thickness covariation in distributed regions of cortex known to be associated with word knowledge. Results indicate that better vocabulary skills are associated with greater anatomical coupling in several linguistically relevant regions of cortex, including the left inferior parietal (temporal-parietal junction), inferior temporal, middle frontal, and superior frontal gyri and the right inferior frontal and precentral gyri. Furthermore, in high vocabulary scorers, stronger coupling is found among these regions. Thus, complementing patient and fMRI studies, this is the first investigation to highlight the relevance of anatomical covariance within the cortex to vocabulary skills in typically developing youth, further elucidating the distributed nature of neural systems subserving word knowledge. Copyright © 2013 Wiley Periodicals, Inc.

  18. The Effect of Different Intensities of Treadmill Exercise on Cognitive Function Deficit Following a Severe Controlled Cortical Impact in Rats

    Directory of Open Access Journals (Sweden)

    Xiafeng Shen

    2013-10-01

    Full Text Available Exercise has been proposed for the treatment of traumatic brain injury (TBI. However, the proper intensity of exercise in the early phase following a severe TBI is largely unknown. To compare two different treadmill exercise intensities on the cognitive function following a severe TBI in its early phase, rats experienced a controlled cortical impact (CCI and were forced to treadmill exercise for 14 days. The results revealed that the rats in the low intensity exercise group had a shorter latency to locate a platform and a significantly better improvement in spatial memory in the Morris water maze (MWM compared to the control group (p 0.05. The brain-derived neurotrophic factor (BDNF and p-CREB protein levels in the contralateral hippocampus were increased significantly in the low intensity exercise group. Our results suggest that 2 weeks of low intensity of treadmill exercise is beneficial for improving cognitive function and increasing hippocampal BDNF expression after a severe TBI in its early phase.

  19. Glutamate concentration in the medial prefrontal cortex predicts resting-state cortical-subcortical functional connectivity in humans.

    Directory of Open Access Journals (Sweden)

    Niall W Duncan

    Full Text Available Communication between cortical and subcortical regions is integral to a wide range of psychological processes and has been implicated in a number of psychiatric conditions. Studies in animals have provided insight into the biochemical and connectivity processes underlying such communication. However, to date no experiments that link these factors in humans in vivo have been carried out. To investigate the role of glutamate in individual differences in communication between the cortex--specifically the medial prefrontal cortex (mPFC--and subcortical regions in humans, a combination of resting-state fMRI, DTI and MRS was performed. The subcortical target regions were the nucleus accumbens (NAc, dorsomedial thalamus (DMT, and periaqueductal grey (PAG. It was found that functional connectivity between the mPFC and each of the NAc and DMT was positively correlated with mPFC glutamate concentrations, whilst functional connectivity between the mPFC and PAG was negatively correlated with glutamate concentration. The correlations involving mPFC glutamate and FC between the mPFC and each of the DMT and PAG were mirrored by correlations with structural connectivity, providing evidence that the glutamatergic relationship may, in part, be due to direct connectivity. These results are in agreement with existing results from animal studies and may have relevance for MDD and schizophrenia.

  20. Graph theory reveals hyper-functionality in visual cortices of Seasonal Affective Disorder patients.

    Science.gov (United States)

    Borchardt, Viola; Krause, Anna Linda; Starck, Tuomo; Nissilä, Juuso; Timonen, Markku; Kiviniemi, Vesa; Walter, Martin

    2015-02-01

    Seasonal affective disorder (SAD) is a subtype of recurrent unipolar or bipolar depressive disorder with a higher prevalence in winter than in summer. The biological underpinnings of SAD are so far poorly understood. Studies examining SAD have found disturbances between the molecular and connectivity scales. The aim of the study was to explore changes in functional connectivity typical for SAD. We investigated unmedicated, untreated SAD patients and healthy controls using resting-state functional magnetic resonance imaging (rs-fMRI) utilizing graph theory, a data driven and hypothesis free approach, to model functional networks of the brain. Comparing whole brain network properties using graph theory we observed globally affected network topologies with increasing pathlength in SAD. Nodal changes, however, were highly restricted to bilateral inferior occipital cortex. Interestingly, we found a lateralization where hyper-connectedness was restricted to right inferior occipital cortex and hyper-efficiency was found in the left inferior occipital cortex. Furthermore, we found these nodes became more "hub like" in patients, suggesting a greater functional role. Our work stresses the importance of abnormal intrinsic processing during rest, primarily affecting visual areas and subsequently changing whole brain networks, and thus providing an important hint towards potential future therapeutic approaches.

  1. Quantitative basis for neuroimaging of cortical laminae with calibrated functional MRI

    OpenAIRE

    Herman, Peter; Sanganahalli, Basavaraju G.; Blumenfeld, Hal; Rothman, Douglas L.; Hyder, Fahmeed

    2013-01-01

    This work challenges the notion that conventional functional magnetic resonance imaging (fMRI), that is, blood oxygenation level-dependent signal alone, can accurately reflect laminar neural activity. Instead, we show that calibrated fMRI methods for metabolic and hemodynamic measurements can better reflect laminar neuronal activities.

  2. Comprehension Strategy Instruction for Two Students with Attention-Related Disabilities

    Science.gov (United States)

    Hedin, Laura R.; Mason, Linda H.; Gaffney, Janet S.

    2011-01-01

    Many students struggle to maintain the attention needed to comprehend while reading. One 4th-grade student and 5th-grade student, both with poor comprehension and attention-related disabilities, were taught to use a proven systematic reading comprehension strategy, TWA (Think Before Reading, Think While Reading, Think After Reading), when reading…

  3. Enhancement of Cortical Excitability and Lower Limb Motor Function in Patients With Stroke by Transcranial Direct Current Stimulation.

    Science.gov (United States)

    Chang, Min Cheol; Kim, Dae Yul; Park, Dae Hwan

    2015-01-01

    Motor dysfunction in the lower limbs is a common sequela in stroke patients. We used transcranial magnetic stimulation (TMS) to determine if applying transcranial direct current stimulation (tDCS) to the primary motor cortex helps enhance cortical excitability. Furthermore, we evaluate if combination anodal tDCS and conventional physical therapy improves motor function in the lower limbs. Twenty-four patients with early-stage stroke were randomly assigned to 2 groups: 1) the tDCS group, in which patients received 10 sessions of anodal tDCS and conventional physical therapy; and 2) the sham group, in which patients received 10 sessions of sham stimulation and conventional physical therapy. One day before and after intervention, the motor-evoked potential (MEP) of the affected tibialis anterior muscle was evaluated and motor function was assessed using the lower limb subscale of the Fugl-Meyer Assessment (FMA-LE), lower limb Motricity Index (MI-LE), Functional Ambulatory Category (FAC), Berg Balance Scale (BBS), and gait analysis. The MEPs in the tDCS group became shorter in latency and higher in amplitude after intervention in comparison with the sham group. Improvements in FMA-LE and MI-LE were greater in the tDCS group, but no significant differences in FAC or BBS scores were found. Also, the changes observed on the gait analyses did not significantly differ between the tDCS and sham groups. Combination anodal tDCS and conservative physical therapy appears to be a beneficial therapeutic modality for improving motor function in the lower limbs in patients with subacute stroke. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Severe motor disability affects functional cortical integration in the context of brain-computer interface (BCI) use.

    Science.gov (United States)

    Nam, Chang S; Woo, Jincheol; Bahn, Sangwoo

    2012-01-01

    The purpose of this study was to investigate cortical interaction between brain regions in people with and without severe motor disability during brain-computer interface (BCI) operation through coherence analysis. Eighteen subjects, including six patients with cerebral palsy (CP) and three patients with amyotrophic lateral sclerosis (ALS), participated. The results showed (1) the existence of BCI performance difference caused by severe motor disability; (2) different coherence patterns between participants with and without severe motor disability during BCI operation and (3) effects of motor disability on cortical connections varying in the brain regions for the different frequency bands, indicating reduced cortical differentiation and specialisation. Participants with severe neuromuscular impairments, as compared with the able-bodied group, recruited more cortical regions to compensate for the difficulties caused by their motor disability, reflecting a less efficient operating strategy for the BCI task. This study demonstrated that coherence analysis can be applied to examine the ways cortical networks cooperate with each other during BCI tasks. Few studies have investigated the electrophysiological underpinnings of differences in BCI performance. This study contributes by assessing neuronal synchrony among brain regions. Our findings revealed that severe motor disability causes more cortical areas to be recruited to perform the BCI task, indicating reduced cortical differentiation and specialisation.

  5. Sustained delivery of nicotinamide limits cortical injury and improves functional recovery following traumatic brain injury

    OpenAIRE

    Goffus, Andrea M.; Anderson, Gail D; Hoane, Michael R.

    2010-01-01

    Previously, we have demonstrated that nicotinamide (NAM), a neuroprotective soluble B-group vitamin, improves recovery of function following traumatic brain injury (TBI). However, no prior studies have examined whether NAM is beneficial following continuous infusions over 7 days post-TBI. The purpose of this study was to investigate the preclinical efficacy of NAM treatment as it might be delivered clinically; over several days by slow infusion. Rats were prepared with either unilateral contr...

  6. Sustained Delivery of Nicotinamide Limits Cortical Injury and Improves Functional Recovery Following Traumatic Brain Injury

    OpenAIRE

    Goffus, Andrea M.; Anderson, Gail D; Hoane, Michael R.

    2010-01-01

    Previously, we have demonstrated that nicotinamide (NAM), a neuroprotective soluble B-group vitamin, improves recovery of function following traumatic brain injury (TBI). However, no prior studies have examined whether NAM is beneficial following continuous infusions over 7 days post-TBI. The purpose of this study was to investigate the preclinical efficacy of NAM treatment as it might be delivered clinically; over several days by slow infusion. Rats were prepared with either unilateral contr...

  7. Altered cortical activation during action observation in amyotrophic lateral sclerosis patients: a parametric functional MRI study

    Energy Technology Data Exchange (ETDEWEB)

    Li, Haiqing; Li, Yuxin; Yin, Bo; Tang, Weijun; Yu, Xiangrong; Geng, Daoying [Huashan Hospital, Department of Radiology, Fudan University, Shanghai (China); Chen, Yan [Fudan University, Department of Neurology, Huashan Hospital, Shanghai (China); Huang, Weiyuan [People' s Hospital of Hainan Province, Department of Radiology, Haikou, Hainan Province (China); Zhang, Biyun [Nanjing University of Traditional Chinese Medicine, Department of radiotherapy, Affiliated Jiangsu Province Hospital of Traditional Chinese Medicine, Nanjing (China)

    2015-09-15

    To investigate functional cerebral abnormalities in patients with amyotrophic lateral sclerosis (ALS) using functional magnetic resonance imaging (fMRI) during action observation. Thirty patients with ALS and 30 matched healthy controls underwent fMRI with an experimental paradigm while observing a video of repetitive flexion-extension of the fingers at three frequency levels or three complexity levels, alternated with periods of a static hand. A parametric analysis was applied to determine the effects of each of the two factors. Action observation activated similar neural networks as the research on execution of action in the ALS patients and healthy subjects in several brain regions related to the mirror-neuron system (MNS). In the ALS patients, in particular, the dorsal lateral premotor cortex (dPMC), inferior parietal gyrus (IPG), and SMA, were more activated compared with the activation in the controls. Increased activation within the primary motor cortex (M1), dPMC, inferior frontal gyrus (IFG), and superior parietal gyrus (SPG) mainly correlated with hand movement frequency/complexity in the videos in the patients compared with controls. The findings indicated an ongoing compensatory process occurring within the higher order motor-processing system of ALS patients, likely to overcome the loss of function. (orig.)

  8. The effect of disruption of prefrontal cortical function with transcranial magnetic stimulation on visual working memory

    Directory of Open Access Journals (Sweden)

    Elizabeth S Lorenc

    2015-12-01

    Full Text Available It is proposed that feedback signals from the prefrontal cortex (PFC to extrastriate cortex are essential for goal-directed processing, maintenance, and selection of information in visual working memory (VWM. In a previous study, we found that disruption of PFC function with transcranial magnetic stimulation (TMS in healthy individuals impaired behavioral performance on a face/scene matching task and decreased category-specific tuning in extrastriate cortex as measured with functional magnetic resonance imaging (fMRI. In this study, we investigated the effect of disruption of left inferior frontal gyrus (IFG function on the fidelity of neural representations of two distinct information codes: (1 the stimulus category and (2 the goal-relevance of viewed stimuli. During fMRI scanning, subjects were presented face and scene images in pseudo-random order and instructed to remember either faces or scenes. Within both anatomical and functional regions of interest, a multi-voxel pattern classifier was used to quantitatively assess the fidelity of activity patterns representing stimulus category: whether a face or a scene was presented on each trial, and goal relevance, whether the presented image was task relevant (i.e. a face is relevant in a Remember Faces block, but irrelevant in a Remember Scenes block. We found a reduction in the fidelity of the stimulus category code in visual cortex after left IFG disruption, providing causal evidence that lateral PFC modulates object category codes in visual cortex during VWM. In addition, we found that IFG disruption caused a reduction in the fidelity of the goal relevance code in a distributed set of brain regions. These results suggest that the IFG is involved in determining the task-relevance of visual input and communicating that information to a network of regions involved in further processing during VWM. Finally, we found that participants who exhibited greater fidelity of the goal relevance code in the

  9. Functional reorganization of a prefrontal cortical network mediating consolidation of trace eyeblink conditioning.

    Science.gov (United States)

    Hattori, Shoai; Yoon, Taejib; Disterhoft, John F; Weiss, Craig

    2014-01-22

    The medial prefrontal cortex (mPFC) has been studied for its role in various cognitive functions, but the roles of its subregions remain unclear. We performed tetrode recordings simultaneously from prelimbic (PL) and rostral (rACC) and caudal (cACC) anterior cingulate subregions of the rabbit mPFC to understand their interactions during learning and tests of remote memory retention for whisker-signaled trace eyeblink conditioning. cACC neurons exhibited an innate response to the conditioning stimulus (CS) that rapidly decreased across sessions, suggesting an attentional role for facilitating CS-US associations. rACC neurons from conditioned rabbits exhibited robust responses to the CS that decreased within each session, possibly evaluating its emotional salience. PL neurons exhibited robust persistent activity during the trace interval during tests of remote memory retention, suggesting its involvement in retrieval and execution of a consolidated response. Mechanistically, conditioning was associated with a greater percentage of persistently responsive neurons than neurons from pseudoconditioned control rabbits, and responses differed significantly between trials with and without conditioned responses. Collectively, these responses reflect a functional reorganization of neural activity within the prefrontal network from an attentional mode to one that orchestrates the retrieval and execution of the learned response.

  10. Cortical activation during clock reading as a quadratic function of dementia state.

    Science.gov (United States)

    Saur, Ralf; Milian, Monika; Erb, Michael; Eschweiler, Gerhard W; Grodd, Wolfgang; Leyhe, Thomas

    2010-01-01

    In patients with Alzheimer's disease (AD), neuroimaging studies have demonstrated decreased brain activation, while increased activation was detected in patients with mild cognitive impairment (MCI). It can be hypothesized that increased cerebral activity seen in patients with MCI reflects neural compensation at the beginning of neurodegenerative processes. Later, as patients develop AD, neural integrity is increasingly impaired. This is accompanied by decreased neural activation. In this study we examined cognitive performance and functional magnetic resonance imaging activation on a Clock Reading task (CRT) and a Spatial Control task (SCT) in healthy controls, patients with MCI, and patients with early AD. Correlations between neural-functional activation and cognitive state, measured by the Mini Mental Status Examination, were determined using rank, linear and quadratic correlation models. It could be shown that CRT, in comparison to SCT, specifically activates brain regions in the ventral visual stream and precuneus known to be involved in conceptual processing and spatial imagery. The correlation between brain activity and cognitive state followed a quadratic rather than a linear pattern in several brain regions, including the lingual gyrus, cuneus, and precuneus. The strongest brain activity was found in patients with MCI and less severely impaired early AD subjects. These findings support the hypothesis that patients in early stages of dementia compensate for neuronal loss by the recruitment of additional neural resources reflected by increased neural activation, as measured by the blood oxygen level-dependent signal.

  11. Fast dynamics of cortical functional and effective connectivity during word reading.

    Directory of Open Access Journals (Sweden)

    Nicolas Bedo

    Full Text Available We describe for the first time the fast dynamics of functional and effective (causal connectivity during word reading. Independent component analysis of high-density EEG recorded during a word reading task recovered multiple sources of electrical brain activity previously identified by fMRI and PET. Results confirmed the ventral occipito-temporal cortex (vOT as a central hub for word reading, showing a progression of theta-band (3-7 Hz and gamma-band (30-50 Hz phase synchronization and directed theta-band and gamma-band information flow with both early visual areas and high-level language-processing areas. These results highlight the interplay between local and long-distance neural dynamics involved at each stage of the reading process. Moreover, these measures of functional and causal connectivity dynamics may be used as a benchmark for comparison with clinical populations (e.g. individuals with developmental dyslexia, such that disturbances in connectivity dynamics may provide insight as to underlying neurological problems with language processing, and their potential remediation.

  12. Functional connectivity change across multiple cortical networks relates to episodic memory changes in aging.

    Science.gov (United States)

    Fjell, Anders M; Sneve, Markus H; Grydeland, Håkon; Storsve, Andreas B; de Lange, Ann-Marie Glasø; Amlien, Inge K; Røgeberg, Ole J; Walhovd, Kristine B

    2015-12-01

    A major task of contemporary cognitive neuroscience of aging is to explain why episodic memory declines. Change in resting-state functional connectivity (rsFC) could be a mechanism accounting for reduced function. We addressed this through 3 studies. In study 1, 119 healthy participants (20-83 years) were followed for 3.5 years with verbal recall testing and magnetic resonance imaging. Independent of atrophy, recall change was related to change in rsFC in anatomically widespread areas. Striking age-effects were observed in that a positive relationship between rsFC and memory characterized older participants while a negative relationship was seen among the younger and middle-aged. This suggests that cognitive consequences of rsFC change are not stable across age. In study 2 and 3, the age-dependent differences in rsFC-memory relationship were replicated by use of a simulation model (study 2) and by a cross-sectional experimental recognition memory task (study 3). In conclusion, memory changes were related to altered rsFC in an age-dependent manner, and future research needs to detail the mechanisms behind age-varying relationships. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Cortical thinning, functional connectivity, and mood-related impulsivity in schizophrenia: relations to aggressive attitudes and behavior

    Science.gov (United States)

    Hoptman, Matthew J.; Antonius, Daniel; Mauro, Cristina J.; Parker, Emily M.; Javitt, Daniel C.

    2014-01-01

    Objective Aggression in schizophrenia is a major societal issue, leading to physical harm, stigmatization, patient distress, and higher healthcare costs. Impulsivity is associated with aggression in schizophrenia, but it is multidetermined. The subconstruct of urgency is likely to play an important role in this aggression, with positive urgency referring to rash action in context of positive emotion, and negative urgency to rash action in context of negative emotion. Method We examined urgency and its neural correlates in 33 patients with schizophrenia or schizoaffective disorder and 31 healthy controls. Urgency was measured using the Urgency, Premeditation, Perseverance and Sensation Seeking scale. Aggressive attitudes were measured using the Buss Perry Aggression Questionnaire. Results Positive urgency, negative urgency, and aggressive attitudes were significantly and selectively elevated in patients (1.21Aggression Questionnaire total score (rs>.48) and each uniquely accounted for a significant portion of the variance in aggression over and above the effect of group. Urgency measures correlated with reduced cortical thickness in ventral prefrontal regions including right frontal pole, medial and lateral orbitofrontal gyrus and inferior frontal gyri, and rostral anterior cingulate cortex. In patients, reduced resting state functional connectivity in some of these regions was associated with higher urgency. Conclusions Findings highlight the key role of urgency in aggressive attitudes in people with schizophrenia and suggest neural substrates of these behaviors. They also suggest behavioral and neural targets for interventions to remediate urgency and aggression. PMID:25073506

  14. Cortical oxygen consumption in mental arithmetic as a function of task difficulty: a near-infrared spectroscopy approach.

    Science.gov (United States)

    Verner, Martin; Herrmann, Martin J; Troche, Stefan J; Roebers, Claudia M; Rammsayer, Thomas H

    2013-01-01

    The present study investigated changes in cortical oxygenation during mental arithmetic using near-infrared spectroscopy (NIRS). Twenty-nine male volunteers were examined using a 52-channel continuous wave system for analyzing activity in prefrontal areas. With the help of a probabilistic mapping method, three regions of interest (ROIs) on each hemisphere were defined: The inferior frontal gyri (IFG), the middle frontal gyri (MFG), and the superior frontal gyri (SFG). Oxygenation as an indicator of functional brain activation was compared over the three ROI and two levels of arithmetic task difficulty (simple and complex additions). In contrast to most previous studies using fMRI or NIRS, in the present study arithmetic tasks were presented verbally in analogue to many daily life situations. With respect to task difficulty, more complex addition tasks led to higher oxygenation in all defined ROI except in the left IFG compared to simple addition tasks. When compared to the channel positions covering different gyri of the temporal lobe, the observed sensitivity to task complexity was found to be restricted to the specified ROIs. As to the comparison of ROIs, the highest oxygenation was found in the IFG, while MFG and SFG showed significantly less activation compared to IFG. The present cognitive-neuroscience approach demonstrated that NIRS is a suitable and highly feasible research tool for investigating and quantifying neural effects of increasing arithmetic task difficulty.

  15. The Optimal Speed for Cortical Activation of Passive Wrist Movements Performed by a Rehabilitation Robot: A Functional NIRS Study.

    Science.gov (United States)

    Bae, Sung Jin; Jang, Sung Ho; Seo, Jeong Pyo; Chang, Pyung Hun

    2017-01-01

    Objectives: To advance development of rehabilitation robots, the conditions to induce appropriate brain activation during rehabilitation performed by robots should be optimized, based on the concept of brain plasticity. In this study, we examined differences in cortical activation according to the speed of passive wrist movements performed by a rehabilitation robot. Methods: Twenty three normal subjects participated in this study. Passive movements of the right wrist were performed by the wrist rehabilitation robot at three different speeds: 0.25 Hz; slow, 0.5 Hz; moderate and 0.75 Hz; fast. We used functional near-infrared spectroscopy to measure the brain activity accompanying the passive movements performed by a robot. The relative changes in oxy-hemoglobin (HbO) were measured in two regions of interest (ROI): the primary sensory-motor cortex (SM1) and premotor area (PMA). Results: In the left SM1 the HbO value was significantly higher at 0.5 Hz, compared with movements performed at 0.25 Hz and 0.75 Hz (p 0.05). In the group analysis, the left SM1 was activated during passive movements at three speeds (uncorrected p rehabilitation robot. Therefore, our results might provide useful data for more effective and empirically-based robot rehabilitation therapy.

  16. Cortical-hippocampal functional connectivity during covert consolidation sub-serves associative learning: Evidence for an active "rest" state.

    Science.gov (United States)

    Ravishankar, Mathura; Morris, Alexandra; Burgess, Ashley; Khatib, Dalal; Stanley, Jeffrey A; Diwadkar, Vaibhav A

    2017-10-18

    We studied modulation of undirected functional connectivity (uFC) in cortical-hippocampal sub-networks during associative learning. Nineteen healthy individuals were studied (fMRI acquired on a Siemens Verio 3T), and uFC was studied between nodes in a network of regions identified by standard activation models based on bivariate correlational analyses of time series data. The paradigm alternated between Memory Encoding, Rest and Retrieval. "Rest" intervals promoted covert consolidation. Over the task, performance was broadly separable into linear (Early) and asymptomatic (Late) regimes, with late performance reflecting successful memory consolidation. Significant modulation of uFC was observed during periods of covert consolidation. The sub-networks which were modulated constituted connections between frontal regions such as the dorsal prefrontal cortex (dPFC) and dorsal anterior cingulate cortex (dACC), the medial temporal lobe (hippocampus, HPC), the superior parietal cortex (SPC) and the fusiform gyrus (FG). uFC patterns were dynamic in that sub-networks modulated during Early learning (dACC ↔ SPC, dACC ↔ FG, dPFC ↔ HPC) were not identical to those modulated during Late learning (dACC ↔ HPC, dPFC ↔ FG, FG ↔ SPC). Covert consolidation exerts systematic effects, and these results add to emerging evidence for the constructive role of the brain's "resting state" in potentiating action. Copyright © 2017. Published by Elsevier Inc.

  17. Array Focal Cortical Stimulation Enhances Motor Function Recovery and Brain Remodeling in a Rat Model of Ischemia.

    Science.gov (United States)

    Yang, Jing; Liu, Lu; Li, Tao; Li, Chengyan

    2017-03-01

    Using a new microelectrode array implanted into the cranial window employing a new stimulation protocol, we investigated the effects of the implanted electrode arrays on both motor map plasticity and neural regeneration in a rodent model of stroke. Rats were pretrained on single-pellet retrieval task, then received focal ischemic infarction and microelectrode arrays implantation. Rats in the cortical stimulation (CS) group received daily electrical stimulation (1 hour each day) for 14 days whereas animals in the no stimulation (NS) group did not receive electrical stimulation and only underwent motor mapping. Behavior data and residual electrophysiological mapping on stimulation days 2, 5, 8, 11, and 14 were statistically compared. Neural reorganization in pathological with glial fibrillary acidic protein and microtubule-associated protein-2 was performed. Rats in CS group showed greater increases in reaching accuracy and significantly decreased in motor threshold than rats in NS group. Immunohistochemical study has shown that array focal CS suppressed inflammatory response, and enhanced dendritic sprouting in the peri-infarction cortex. The present findings support the viability of epidural CS with microelectrode arrays for enhancing motor function after stroke and monitoring the neural reorganization of residual electrophysiological mapping after motor cortex injury. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  18. Functional connectivity in cortical regions in dementia with Lewy bodies and Alzheimer's disease.

    Science.gov (United States)

    Kenny, Eva R; Blamire, Andrew M; Firbank, Michael J; O'Brien, John T

    2012-02-01

    Using resting-state functional magnetic resonance imaging, spontaneous low-frequency fluctuations in the blood oxygenation level-dependent signal were measured to investigate connectivity between key brain regions hypothesized to be differentially affected in dementia with Lewy bodies compared with Alzheimer's disease and healthy controls. These included connections of the hippocampus, because of its role in learning, and parietal and occipital areas involved in memory, attention and visual processing. Connectivity was investigated in 47 subjects aged 60 years and over: 15 subjects with dementia with Lewy bodies, 16 subjects with Alzheimer's disease and 16 control subjects. Subjects were scanned using a 3 Tesla magnetic resonance imaging system. The mean blood oxygenation level-dependent signal time series was extracted from seed regions in the hippocampus, posterior cingulate cortex, precuneus and primary visual cortex and correlated with all other brain voxels to determine functional connectivity. Both subjects with dementia with Lewy bodies and Alzheimer's disease showed greater connectivity than control subjects. Compared with controls, the dementia with Lewy bodies group had greater connectivity between the right posterior cingulate cortex and other brain areas. In dementia with Lewy bodies, there were no significant differences in hippocampal connectivity compared with controls, but in Alzheimer's disease left hippocampal connectivity was greater compared with controls. There were no significant differences between groups for precuneus or primary visual cortex connectivity. No seed regions showed significantly less connectivity in subjects with dementia with Lewy bodies or Alzheimer's disease compared with controls. We found greater connectivity with the posterior cingulate in dementia with Lewy bodies and with the hippocampus in Alzheimer's disease. Consistent with the known relative preservation of memory in dementia with Lewy bodies compared with Alzheimer

  19. Functional connectivity in cortical regions in dementia with Lewy bodies and Alzheimer's disease

    Science.gov (United States)

    Blamire, Andrew M.; Firbank, Michael J.; O'Brien, John T.

    2012-01-01

    Using resting-state functional magnetic resonance imaging, spontaneous low-frequency fluctuations in the blood oxygenation level-dependent signal were measured to investigate connectivity between key brain regions hypothesized to be differentially affected in dementia with Lewy bodies compared with Alzheimer's disease and healthy controls. These included connections of the hippocampus, because of its role in learning, and parietal and occipital areas involved in memory, attention and visual processing. Connectivity was investigated in 47 subjects aged 60 years and over: 15 subjects with dementia with Lewy bodies, 16 subjects with Alzheimer's disease and 16 control subjects. Subjects were scanned using a 3 Tesla magnetic resonance imaging system. The mean blood oxygenation level-dependent signal time series was extracted from seed regions in the hippocampus, posterior cingulate cortex, precuneus and primary visual cortex and correlated with all other brain voxels to determine functional connectivity. Both subjects with dementia with Lewy bodies and Alzheimer's disease showed greater connectivity than control subjects. Compared with controls, the dementia with Lewy bodies group had greater connectivity between the right posterior cingulate cortex and other brain areas. In dementia with Lewy bodies, there were no significant differences in hippocampal connectivity compared with controls, but in Alzheimer's disease left hippocampal connectivity was greater compared with controls. There were no significant differences between groups for precuneus or primary visual cortex connectivity. No seed regions showed significantly less connectivity in subjects with dementia with Lewy bodies or Alzheimer's disease compared with controls. We found greater connectivity with the posterior cingulate in dementia with Lewy bodies and with the hippocampus in Alzheimer's disease. Consistent with the known relative preservation of memory in dementia with Lewy bodies compared with Alzheimer

  20. Functional connectivity and dynamics of cortical-thalamic networks co-cultured in a dual compartment device

    Science.gov (United States)

    Kanagasabapathi, Thirukumaran T.; Massobrio, Paolo; Barone, Rocco Andrea; Tedesco, Mariateresa; Martinoia, Sergio; Wadman, Wytse J.; Decré, Michel M. J.

    2012-06-01

    Co-cultures containing dissociated cortical and thalamic cells may provide a unique model for understanding the pathophysiology in the respective neuronal sub-circuitry. In addition, developing an in vitro dissociated co-culture model offers the possibility of studying the system without influence from other neuronal sub-populations. Here we demonstrate a dual compartment system coupled to microelectrode arrays (MEAs) for co-culturing and recording spontaneous activities from neuronal sub-populations. Propagation of electrical activities between cortical and thalamic regions and their interdependence in connectivity is verified by means of a cross-correlation algorithm. We found that burst events originate in the cortical region and drive the entire cortical-thalamic network bursting behavior while mutually weak thalamic connections play a relevant role in sustaining longer burst events in cortical cells. To support these experimental findings, a neuronal network model was developed and used to investigate the interplay between network dynamics and connectivity in the cortical-thalamic system.

  1. Morphological and behavioral evidence for impaired prefrontal cortical function in female CB1 receptor deficient mice.

    Science.gov (United States)

    Lee, Tiffany T-Y; Filipski, Sarah B; Hill, Matthew N; McEwen, Bruce S

    2014-09-01

    The medial prefrontal cortex (mPFC) is known to regulate higher order processes like cognitive flexibility. Accumulating behavioral evidence suggests that endocannabinoid (eCB) signaling regulates neuronal architecture within the PFC, as well as certain forms of cognitive flexibility; however, all of these studies have been performed in male rodents and it is currently unknown whether the eCB system performs a similar role in females. To this extent, dendritic morphology of layer II/III neurons in the infra- and prelimbic regions of the mPFC was analyzed and cognitive ability and flexibility in a fixed-platform Morris water maze task was assessed in adult female CB1 receptor knockout (CB1KO) mice. Similar to data generated in male mice, female mice exhibited no difference in acquisition relative to wildtype (WT); however, during reversal learning, CB1KO females spent more time in the original training quadrant and took significantly longer to learn the location of the new platform relative to WT. Within the mPFC, female mice had reduced length and complexity of layer II/III neurons within the prelimbic, but not infralimbic region of the PFC. Taken together, these findings indicate that the role of eCB signaling in cognitive flexibility is independent of sex and disrupted CB1 receptor signaling results in compromised structure and function of the PFC, at least within the prelimbic division. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Effects of Melatonin on Adrenal Cortical Functions of Indian Goats under Thermal Stress

    Directory of Open Access Journals (Sweden)

    Veerasamy Sejian

    2010-01-01

    Full Text Available The study was conducted with the primary objective to establish the influence of melatonin on adrenocortical functions to ameliorate thermal stress in goats. Endocrine secretions and several other blood biochemical parameters reflecting the animals adrenocortical stress response were determined over a one-week period after goats had been exposed to 40C∘ and 60%RH for 10 days. The study was conducted for a period of 17 days in psychrometric chamber. The animals served as self-controls prior to start of the experiment. Blood samples were drawn on day 10 to establish effect of thermal stress. Chemical adrenalectomy was achieved using metyrapone followed by exogenous melatonin treatment. 40C∘ of thermal stress which is quite normal in tropical zone significantly (P≤.05 influenced all parameters except plasma insulin. Metyrapone treatment significantly (P≤.05 affected plasma levels of glucose, total protein, total cholesterol, cortisol, and aldosterone. Metyrapone aggravated thermal stress by decreasing cortisol level in goats. Melatonin treatment at 11:00 AM significantly (P≤.05 influenced plasma levels of glucose, total protein, total cholesterol, cortisol, aldosterone and insulin. Metyrapone treatment aggravated thermal stress although administration of melatonin could ameliorate the condition. This establishes the role of melatonin in relieving thermal stress in goats.

  3. Coherence between brain cortical function and neurocognitive performance during changed gravity conditions.

    Science.gov (United States)

    Brümmer, Vera; Schneider, Stefan; Vogt, Tobias; Strüder, Heiko; Carnahan, Heather; Askew, Christopher D; Csuhaj, Roland

    2011-05-23

    Previous studies of cognitive, mental and/or motor processes during short-, medium- and long-term weightlessness have only been descriptive in nature, and focused on psychological aspects. Until now, objective observation of neurophysiological parameters has not been carried out--undoubtedly because the technical and methodological means have not been available--, investigations into the neurophysiological effects of weightlessness are in their infancy (Schneider et al. 2008). While imaging techniques such as positron emission tomography (PET) and magnetic resonance imaging (MRI) would be hardly applicable in space, the non-invasive near-infrared spectroscopy (NIRS) technique represents a method of mapping hemodynamic processes in the brain in real time that is both relatively inexpensive and that can be employed even under extreme conditions. The combination with electroencephalography (EEG) opens up the possibility of following the electrocortical processes under changing gravity conditions with a finer temporal resolution as well as with deeper localization, for instance with electrotomography (LORETA). Previous studies showed an increase of beta frequency activity under normal gravity conditions and a decrease under weightlessness conditions during a parabolic flight (Schneider et al. 2008a+b). Tilt studies revealed different changes in brain function, which let suggest, that changes in parabolic flight might reflect emotional processes rather than hemodynamic changes. However, it is still unclear whether these are effects of changed gravity or hemodynamic changes within the brain. Combining EEG/LORETA and NIRS should for the first time make it possible to map the effect of weightlessness and reduced gravity on both hemodynamic and electrophysiological processes in the brain. Initially, this is to be done as part of a feasibility study during a parabolic flight. Afterwards, it is also planned to use both techniques during medium- and long-term space flight. It

  4. Strategy-based reasoning training modulates cortical thickness and resting-state functional connectivity in adults with chronic traumatic brain injury.

    Science.gov (United States)

    Han, Kihwan; Davis, Rebecca A; Chapman, Sandra B; Krawczyk, Daniel C

    2017-05-01

    Prior studies have demonstrated training-induced changes in the healthy adult brain. Yet, it remains unclear how the injured brain responds to cognitive training months-to-years after injury. Sixty individuals with chronic traumatic brain injury (TBI) were randomized into either strategy-based (N = 31) or knowledge-based (N = 29) training for 8 weeks. We measured cortical thickness and resting-state functional connectivity (rsFC) before training, immediately posttraining, and 3 months posttraining. Relative to the knowledge-based training group, the cortical thickness of the strategy-based training group showed diverse temporal patterns of changes over multiple brain regions (pvertex training group induced only monotonic increases in connectivity, relative to the knowledge-based training group (|Z| > 1.96, pNBS training group yielded monotonic improvement in scores for the trail-making test (p brain-behavior relationships revealed that improvement in trail-making scores were associated with training-induced changes in cortical thickness (pvertex training group. These findings suggest that training-induced brain plasticity continues through chronic phases of TBI and that brain connectivity and cortical thickness may serve as markers of plasticity.

  5. Mapping cortical hand motor representation using TMS: A method to assess brain plasticity and a surrogate marker for recovery of function after stroke?

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    Lüdemann-Podubecká, Jitka; Nowak, Dennis Alexander

    2016-10-01

    Stroke is associated with reorganization within motor areas of both hemispheres. Mapping the cortical hand motor representation using transcranial magnetic stimulation may help to understand the relationship between motor cortex reorganization and motor recovery of the affected hand after stroke. A standardized review of the pertinent literature was performed. We identified 20 trials, which analyzed the relationship between the extent and/or location of cortical hand motor representation using transcranial magnetic stimulation and motor function and recovery of the affected hand. Several correlations were found between cortical reorganization and measures of hand motor impairment and recovery. A better understanding of the relationships between the extent and location of cortical hand motor representation and the motor impairment and motor recovery of the affected hand after stroke may contribute to a targeted use of non-invasive brain stimulation protocols. In the future motor mapping may help to guide brain stimulation techniques to the most effective motor area in an affected individual. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Best facilitated cortical activation during different stepping, treadmill, and robot-assisted walking training paradigms and speeds: A functional near-infrared spectroscopy neuroimaging study.

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    Kim, Ha Yeon; Yang, Sung Phil; Park, Gyu Lee; Kim, Eun Joo; You, Joshua Sung Hyun

    2016-01-01

    Robot-assisted and treadmill-gait training are promising neurorehabilitation techniques, with advantages over conventional gait training, but the neural substrates underpinning locomotor control remain unknown particularly during different gait training modes and speeds. The present optical imaging study compared cortical activities during conventional stepping walking (SW), treadmill walking (TW), and robot-assisted walking (RW) at different speeds. Fourteen healthy subjects (6 women, mean age 30.06, years ± 4.53) completed three walking training modes (SW, TW, and RW) at various speeds (self-selected, 1.5, 2.0, 2.5, and 3.0  km/h). A functional near-infrared spectroscopy (fNIRS) system determined cerebral hemodynamic changes associated with cortical locomotor network areas in the primary sensorimotor cortex (SMC), premotor cortex (PMC), supplementary motor area (SMA), prefrontal cortex (PFC), and sensory association cortex (SAC). There was increased cortical activation in the SMC, PMC, and SMA during different walking training modes. More global locomotor network activation was observed during RW than TW or SW. As walking speed increased, multiple locomotor network activations were observed, and increased activation power spectrum. This is the first empirical evidence highlighting the neural substrates mediating dynamic locomotion for different gait training modes and speeds. Fast, robot-assisted gait training best facilitated cortical activation associated with locomotor control.

  7. 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.

  8. [On the question of the organization of brain function: cortical associations, «disconnection» syndrome and higher brain functions].

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    Damulin, I V

    2015-01-01

    The review considers the structural/functional brain organization, the disturbance of which is accompanied by the development of cognitive and behavioral disorders. The significance of the disruption of parallel circuits connecting frontal lobes with subcortical structures (the basal ganglia, thalamus, cerebellum) is highlighted. This disruption is clinically described as "disconnection" syndrome. The associations between the basal ganglia and the cortex of the large cerebral hemispheres responsible for motor, cognitive and emotional/behavioral functions do not restricted to these spheres and is characteristic not only of frontal brain areas. There are circuits connecting other brain compartments and the basal ganglia that provide perception, and are involved in decision making on the basis of input information of different modalities.The improvement of understanding of the pathophysiology and neurochemistry of these structures opens new possibilities for selective action on some or other circuit to achieve the best therapeutic result.

  9. Neurophysiological Evidence of Compensatory Brain Mechanisms Underlying Attentional-Related Processes in Symptomatically Remitted Patients with Schizophrenia

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    Yansong Li

    2017-04-01

    Full Text Available A recent electrophysiological study suggests existing compensatory brain activity as a mechanism for functional recovery of visual attention detection (the capacity for detecting external cues in symptomatically remitted schizophrenia patients. Despite such evidence, little is known about other aspects of attentional-related processes in schizophrenia during clinical remission, such as their capacity to concentrate on the task at hands without being interfered by distracting information. To this end, we recorded event-related brain potentials (ERPs from 20 symptomatically remitted schizophrenia patients and 20 healthy controls while they engaged in a classic Stroop task. Symptomatically remitted patients showed comparable Stroop interference to healthy controls, indicating a degree of functional recovery of such a capacity in these patients. On the neural level, the N450 over the fronto-central and central regions, a component of the ERPs related to conflict detection, was found across both groups, although patients presented a reduced N450 relative to healthy controls. By contrast, the amplitude of the sustained potential (SP (600–800 ms over the parieto-central and parietal regions, a component of the ERPs related to conflict resolution, was significantly increased in patients relative to healthy controls. Furthermore, such increased SP amplitude correlated positively with improved behavioral accuracy in symptomatically remitted patients with schizophrenia. These findings reveal that symptomatically remitted patients with schizophrenia increasingly recruited the parietal activity involving successful conflict resolution to offset reduced conflict detection. Therefore, this provides further insight into compensatory mechanisms potentially involving a degree of functional recovery of attentional-related processes in schizophrenia during clinical remission.

  10. Cortical thinning, functional connectivity, and mood-related impulsivity in schizophrenia: relationship to aggressive attitudes and behavior.

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    Hoptman, Matthew J; Antonius, Daniel; Mauro, Cristina J; Parker, Emily M; Javitt, Daniel C

    2014-09-01

    Aggression in schizophrenia is a major societal issue, leading to physical harm, stigmatization, patient distress, and higher health care costs. Impulsivity is associated with aggression in schizophrenia, but it is multidetermined. The subconstruct of urgency is likely to play an important role in this aggression, with positive urgency referring to rash action in the context of positive emotion, and negative urgency referring to rash action in the context of negative emotion. The authors examined urgency and its neural correlates in 33 patients with schizophrenia or schizoaffective disorder and 31 healthy comparison subjects. Urgency was measured using the Urgency, Premeditation, Perseverance, and Sensation-Seeking scale. Aggressive attitudes were measured using the Buss-Perry Aggression Questionnaire. Positive urgency, negative urgency, and aggressive attitudes were significantly and selectively elevated in schizophrenia patients (Cohen's d values, 1.21-1.50). Positive and negative urgency significantly correlated with the Aggression Questionnaire total score (r>0.48 in all cases) and each uniquely accounted for a significant portion of the variance in aggression over and above the effect of group. Urgency scores correlated with reduced cortical thickness in ventral prefrontal regions including the right frontal pole, the medial and lateral orbitofrontal gyrus and inferior frontal gyri, and the rostral anterior cingulate cortex. In patients, reduced resting-state functional connectivity in some of these regions was associated with higher urgency. These findings highlight the key role of urgency in aggressive attitudes in people with schizophrenia and suggest neural substrates of these behaviors. The results also suggest behavioral and neural targets for interventions to remediate urgency and aggression.

  11. Quantitative Live Imaging of Human Embryonic Stem Cell Derived Neural Rosettes Reveals Structure-Function Dynamics Coupled to Cortical Development.

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    Ziv, Omer; Zaritsky, Assaf; Yaffe, Yakey; Mutukula, Naresh; Edri, Reuven; Elkabetz, Yechiel

    2015-10-01

    Neural stem cells (NSCs) are progenitor cells for brain development, where cellular spatial composition (cytoarchitecture) and dynamics are hypothesized to be linked to critical NSC capabilities. However, understanding cytoarchitectural dynamics of this process has been limited by the difficulty to quantitatively image brain development in vivo. Here, we study NSC dynamics within Neural Rosettes--highly organized multicellular structures derived from human pluripotent stem cells. Neural rosettes contain NSCs with strong epithelial polarity and are expected to perform apical-basal interkinetic nuclear migration (INM)--a hallmark of cortical radial glial cell development. We developed a quantitative live imaging framework to characterize INM dynamics within rosettes. We first show that the tendency of cells to follow the INM orientation--a phenomenon we referred to as radial organization, is associated with rosette size, presumably via mechanical constraints of the confining structure. Second, early forming rosettes, which are abundant with founder NSCs and correspond to the early proliferative developing cortex, show fast motions and enhanced radial organization. In contrast, later derived rosettes, which are characterized by reduced NSC capacity and elevated numbers of differentiated neurons, and thus correspond to neurogenesis mode in the developing cortex, exhibit slower motions and decreased radial organization. Third, later derived rosettes are characterized by temporal instability in INM measures, in agreement with progressive loss in rosette integrity at later developmental stages. Finally, molecular perturbations of INM by inhibition of actin or non-muscle myosin-II (NMII) reduced INM measures. Our framework enables quantification of cytoarchitecture NSC dynamics and may have implications in functional molecular studies, drug screening, and iPS cell-based platforms for disease modeling.

  12. The Optimal Speed for Cortical Activation of Passive Wrist Movements Performed by a Rehabilitation Robot: A Functional NIRS Study

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    Pyung Hun Chang

    2017-04-01

    Full Text Available Objectives: To advance development of rehabilitation robots, the conditions to induce appropriate brain activation during rehabilitation performed by robots should be optimized, based on the concept of brain plasticity. In this study, we examined differences in cortical activation according to the speed of passive wrist movements performed by a rehabilitation robot.Methods: Twenty three normal subjects participated in this study. Passive movements of the right wrist were performed by the wrist rehabilitation robot at three different speeds: 0.25 Hz; slow, 0.5 Hz; moderate and 0.75 Hz; fast. We used functional near-infrared spectroscopy to measure the brain activity accompanying the passive movements performed by a robot. The relative changes in oxy-hemoglobin (HbO were measured in two regions of interest (ROI: the primary sensory-motor cortex (SM1 and premotor area (PMA.Results: In the left SM1 the HbO value was significantly higher at 0.5 Hz, compared with movements performed at 0.25 Hz and 0.75 Hz (p < 0.05, while no significant differences were observed in the left PMA (p > 0.05. In the group analysis, the left SM1 was activated during passive movements at three speeds (uncorrected p < 0.05 and the greatest activation in the SM1 was observed at 0.5 Hz.Conclusions: In conclusion, the contralateral SM1 showed the greatest activation by a moderate speed (0.5 Hz rather than slow (0.25 Hz and fast (0.75 Hz speed. Our results suggest an ideal speed for execution of the wrist rehabilitation robot. Therefore, our results might provide useful data for more effective and empirically-based robot rehabilitation therapy.

  13. Prenatal exposure to cannabinoids evokes long-lasting functional alterations by targeting CB1 receptors on developing cortical neurons.

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    de Salas-Quiroga, Adán; Díaz-Alonso, Javier; García-Rincón, Daniel; Remmers, Floortje; Vega, David; Gómez-Cañas, María; Lutz, Beat; Guzmán, Manuel; Galve-Roperh, Ismael

    2015-11-03

    The CB1 cannabinoid receptor, the main target of Δ(9)-tetrahydrocannabinol (THC), the most prominent psychoactive compound of marijuana, plays a crucial regulatory role in brain development as evidenced by the neurodevelopmental consequences of its manipulation in animal models. Likewise, recreational cannabis use during pregnancy affects brain structure and function of the progeny. However, the precise neurobiological substrates underlying the consequences of prenatal THC exposure remain unknown. As CB1 signaling is known to modulate long-range corticofugal connectivity, we analyzed the impact of THC exposure on cortical projection neuron development. THC administration to pregnant mice in a restricted time window interfered with subcerebral projection neuron generation, thereby altering corticospinal connectivity, and produced long-lasting alterations in the fine motor performance of the adult offspring. Consequences of THC exposure were reminiscent of those elicited by CB1 receptor genetic ablation, and CB1-null mice were resistant to THC-induced alterations. The identity of embryonic THC neuronal targets was determined by a Cre-mediated, lineage-specific, CB1 expression-rescue strategy in a CB1-null background. Early and selective CB1 reexpression in dorsal telencephalic glutamatergic neurons but not forebrain GABAergic neurons rescued the deficits in corticospinal motor neuron development of CB1-null mice and restored susceptibility to THC-induced motor alterations. In addition, THC administration induced an increase in seizure susceptibility that was mediated by its interference with CB1-dependent regulation of both glutamatergic and GABAergic neuron development. These findings demonstrate that prenatal exposure to THC has long-lasting deleterious consequences in the adult offspring solely mediated by its ability to disrupt the neurodevelopmental role of CB1 signaling.

  14. Quantitative Live Imaging of Human Embryonic Stem Cell Derived Neural Rosettes Reveals Structure-Function Dynamics Coupled to Cortical Development.

    Directory of Open Access Journals (Sweden)

    Omer Ziv

    2015-10-01

    Full Text Available Neural stem cells (NSCs are progenitor cells for brain development, where cellular spatial composition (cytoarchitecture and dynamics are hypothesized to be linked to critical NSC capabilities. However, understanding cytoarchitectural dynamics of this process has been limited by the difficulty to quantitatively image brain development in vivo. Here, we study NSC dynamics within Neural Rosettes--highly organized multicellular structures derived from human pluripotent stem cells. Neural rosettes contain NSCs with strong epithelial polarity and are expected to perform apical-basal interkinetic nuclear migration (INM--a hallmark of cortical radial glial cell development. We developed a quantitative live imaging framework to characterize INM dynamics within rosettes. We first show that the tendency of cells to follow the INM orientation--a phenomenon we referred to as radial organization, is associated with rosette size, presumably via mechanical constraints of the confining structure. Second, early forming rosettes, which are abundant with founder NSCs and correspond to the early proliferative developing cortex, show fast motions and enhanced radial organization. In contrast, later derived rosettes, which are characterized by reduced NSC capacity and elevated numbers of differentiated neurons, and thus correspond to neurogenesis mode in the developing cortex, exhibit slower motions and decreased radial organization. Third, later derived rosettes are characterized by temporal instability in INM measures, in agreement with progressive loss in rosette integrity at later developmental stages. Finally, molecular perturbations of INM by inhibition of actin or non-muscle myosin-II (NMII reduced INM measures. Our framework enables quantification of cytoarchitecture NSC dynamics and may have implications in functional molecular studies, drug screening, and iPS cell-based platforms for disease modeling.

  15. Theory of cortical function.

    Science.gov (United States)

    Heeger, David J

    2017-02-21

    Most models of sensory processing in the brain have a feedforward architecture in which each stage comprises simple linear filtering operations and nonlinearities. Models of this form have been used to explain a wide range of neurophysiological and psychophysical data, and many recent successes in artificial intelligence (with deep convolutional neural nets) are based on this architecture. However, neocortex is not a feedforward architecture. This paper proposes a first step toward an alternative computational framework in which neural activity in each brain area depends on a combination of feedforward drive (bottom-up from the previous processing stage), feedback drive (top-down context from the next stage), and prior drive (expectation). The relative contributions of feedforward drive, feedback drive, and prior drive are controlled by a handful of state parameters, which I hypothesize correspond to neuromodulators and oscillatory activity. In some states, neural responses are dominated by the feedforward drive and the theory is identical to a conventional feedforward model, thereby preserving all of the desirable features of those models. In other states, the theory is a generative model that constructs a sensory representation from an abstract representation, like memory recall. In still other states, the theory combines prior expectation with sensory input, explores different possible perceptual interpretations of ambiguous sensory inputs, and predicts forward in time. The theory, therefore, offers an empirically testable framework for understanding how the cortex accomplishes inference, exploration, and prediction.

  16. Improved Diagnostic Accuracy of Alzheimer's Disease by Combining Regional Cortical Thickness and Default Mode Network Functional Connectivity: Validated in the Alzheimer's Disease Neuroimaging Initiative Set.

    Science.gov (United States)

    Park, Ji Eun; Park, Bumwoo; Kim, Sang Joon; Kim, Ho Sung; Choi, Choong Gon; Jung, Seung Chai; Oh, Joo Young; Lee, Jae-Hong; Roh, Jee Hoon; Shim, Woo Hyun

    2017-01-01

    To identify potential imaging biomarkers of Alzheimer's disease by combining brain cortical thickness (CThk) and functional connectivity and to validate this model's diagnostic accuracy in a validation set. Data from 98 subjects was retrospectively reviewed, including a study set (n = 63) and a validation set from the Alzheimer's Disease Neuroimaging Initiative (n = 35). From each subject, data for CThk and functional connectivity of the default mode network was extracted from structural T1-weighted and resting-state functional magnetic resonance imaging. Cortical regions with significant differences between patients and healthy controls in the correlation of CThk and functional connectivity were identified in the study set. The diagnostic accuracy of functional connectivity measures combined with CThk in the identified regions was evaluated against that in the medial temporal lobes using the validation set and application of a support vector machine. Group-wise differences in the correlation of CThk and default mode network functional connectivity were identified in the superior temporal (p functional connectivity combined with the CThk of those two regions were more accurate than that combined with the CThk of both medial temporal lobes (91.7% vs. 75%). Combining functional information with CThk of the superior temporal and supramarginal gyri in the left cerebral hemisphere improves diagnostic accuracy, making it a potential imaging biomarker for Alzheimer's disease.

  17. 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.)

  18. The cortical acto-myosin network: from diffusion barrier to functional gateway in the transport of neurosecretory vesicles to the plasma membrane

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    Andreas ePapadopulos

    2013-10-01

    Full Text Available Dysregulation of regulated exocytosis is linked to an array of pathological conditions, including neurodegenerative disorders, asthma and diabetes. Understanding the molecular mechanisms underpinning neuroexocytosis including the processes that allow neurosecretory vesicles to access and fuse with the plasma membrane and to recycle post-fusion, is therefore critical to the design of future therapeutic drugs that will efficiently tackle these diseases. Despite considerable efforts to determine the principles of vesicular fusion, the mechanisms controlling the approach of vesicles to the plasma membrane in order to undergo tethering, docking, priming, and fusion remain poorly understood. All these steps involve the cortical actin network, a dense mesh of actin filaments localized beneath the plasma membrane. Recent work overturned the long-held belief that the cortical actin network only plays a passive constraining role in neuroexocytosis functioning as a physical barrier that partly breaks down upon entry of Ca2+ to allow secretory vesicles to reach the plasma membrane. A multitude of new roles for the cortical actin network in regulated exocytosis have now emerged and point to highly dynamic novel functions of key myosin molecular motors. Myosins are not only believed to help bring about dynamic changes in the actin cytoskeleton, tethering and guiding vesicles to their fusion sites, but they also regulate the size and duration of the fusion pore, thereby directly contributing to the release of neurotransmitters and hormones.Here we discuss the functions of the cortical actin network, myosins and their effectors in controlling the processes that lead to tethering, directed transport, docking, and fusion of exocytotic vesicles in regulated exocytosis.

  19. [Cortical control in locomotion].

    Science.gov (United States)

    Mori, Futoshi; Nakajima, Katsumi

    2010-11-01

    Although simple in appearance, bipedal (Bp) and even quadrupedal (Qp) locomotion are highly tuned motor behaviors that require coordinated control in the spatial and temporal domains of head, neck, trunk, and limbs. Seamless integration of limb movements and accompanying posture is a crucial determinant for the execution of desired locomotor movements. Recent functional brain imaging studies have shown that multiple cerebral sensorimotor cortices and the cerebellum are highly activated during human BP locomotion, suggesting that humans depend on the cerebrum and cerebellum for the elaboration of Bp locomotion. We have found that a young Japanese monkey, Macaca fuscata, acquires novel Bp walking capability with a long-term locomotor task and physical maturation. This model animal has kinematic features that are common with those of humans. Our imaging study showed that multiple cortical motor related areas are activated during monkey Bp walking, similar to that observed in humans. Furthermore, cortical inactivation studies revealed that each cortical region has an assigned functional role for the elaboration and refinements of its locomotor task. All these results show that selective yet multiple involvement of cortical motor regions are necessary for the elaboration of Bp locomotion in both humans and non-human primate models. Presumably, such multi-faceted recruitment of motor cortices is required to accommodate the limb movement and postural demands for Bp upright standing and walking. To cure locomotor dysfunctions due to CNS impairments, it is necessary to understand the CNS mechanisms involved in fine-tuning of limb movements and accompanying posture. Multi-comparative interdisciplinary studies should be initiated to reveal the CNS mechanisms involved in the control of Bp upright standing and locomotion in humans and non-human primate models.

  20. Cortical and white matter mapping in the visual system- more than meets theeye: on the importance of functional imaging to understand visual systempathologies

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    Noa eRaz

    2014-08-01

    Full Text Available Information transmission within the visual system is highly organized with the ultimate goal of accomplishing higher-order, complex visuo-spatial and object identity processing. Perception is dependent on the intactness of the entire system and damage at each stage – in the eye itself, the visual pathways, or within cortical processing - might result in perception disturbance.Herein we will review several examples of lesions along the visual system, from the retina, via the optic nerve and chiasm and through the occipital cortex. We will address their clinical manifestation and their cortical substrate. The latter will be studied via functional magnetic resonance imaging (fMRI and Diffusion Tensor Imaging (DTI, enabling cortical and white matter mapping of the human brain. In contrast to traditional signal recording, these procedures enable simultaneous evaluation of the entire brain network engaged when subjects undertake a particular task or evaluate the entirety of associated white matter pathways.These examples provided will highlight the importance of using advanced imaging methods to better understand visual pathologies. We will argue that clinical manifestation cannot always be explained solely by structural damage and a functional view is required to understand the clinical symptom. In such cases we recommend using advanced imaging methods to better understand the neurological basis of visual phenomena.

  1. Value of renal cortical thickness as a predictor of renal function impairment in chronic renal disease patients

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    Samia Rafael Yamashita

    2015-02-01

    Full Text Available Objective: To determine the presence of linear relationship between renal cortical thickness, bipolar length, and parenchymal thickness in chronic kidney disease patients presenting with different estimated glomerular filtration rates (GFRs and to assess the reproducibility of these measurements using ultrasonography. Materials and Methods: Ultrasonography was performed in 54 chronic renal failure patients. The scans were performed by two independent and blinded radiologists. The estimated GFR was calculated using the Cockcroft-Gault equation. Interobserver agreement was calculated and a linear correlation coefficient (r was determined in order to establish the relationship between the different renal measurements and estimated GFR. Results: The correlation between GFR and measurements of renal cortical thickness, bipolar length, and parenchymal thickness was, respectively, moderate (r = 0.478; p < 0.001, poor (r = 0.380; p = 0.004, and poor (r = 0.277; p = 0.116. The interobserver agreement was considered excellent (0.754 for measurements of cortical thickness and bipolar length (0.833, and satisfactory for parenchymal thickness (0.523. Conclusion: The interobserver reproducibility for renal measurements obtained was good. A moderate correlation was observed between estimated GFR and cortical thickness, but bipolar length and parenchymal thickness were poorly correlated.

  2. Neuroimaging to detect cortical projection of vestibular response to caloric stimulation in young and older adults using functional near-infrared spectroscopy (fNIRS).

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    Karim, H T; Fuhrman, S I; Furman, J M; Huppert, T J

    2013-08-01

    Functional near-infrared spectroscopy (fNIRS) is a non-invasive and portable neuroimaging technique. The method uses non-ionizing laser light in the range of red to near-infrared to detect changes in cerebral blood oxygenation. In this study, we used fNIRS to investigate cortical hemodynamic changes in the temporo-parietal and frontal regions during caloric vestibular stimulation. Caloric stimulation has previously been investigated using functional magnetic resonance imaging (fMRI) and positron emission tomography (PET), which serves as a validation of the fNIRS imaging modality toward the measurement of vestibular related brain regions. To date, only a single study has used fNIRS during caloric irrigations, which observed blood volume changes in the temporal-parietal area in healthy younger subjects. In this current study, fNIRS was used to measure cortical vestibular activation in 10 right-handed younger subjects (5 male and 5 female, age 25+/-6 years) and 10 right-handed older subjects (6 male and 4 female, age 74+/-5 years). We investigated both warm (44 °C) and cool (30 °C) unilateral caloric vestibular stimulation. Consistent with previous reports, we found that warm (44 °C) caloric irrigation caused a bilateral activation. In addition, we found that cool (30 °C) caloric irrigation caused contralateral activation of the temporo-parietal area. This study is the first to investigate age effects of the caloric stimulation on brain activity. We found that the older subjects had stronger bilateral effects than the younger subjects. Our results confirm previous fMRI and PET studies that showed cortical activation during caloric vestibular irrigation is dependent on side of irrigation, and temperature of irrigation. Furthermore, our results demonstrate that fNIRS is a viable technique in measuring cortical effects during vestibular tasks. Copyright © 2013 Elsevier Inc. All rights reserved.

  3. Association between rostral prefrontal cortical activity and functional outcome in first-episode psychosis: a longitudinal functional near-infrared spectroscopy study.

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    Koike, Shinsuke; Satomura, Yoshihiro; Kawasaki, Shingo; Nishimura, Yukika; Takano, Yosuke; Iwashiro, Norichika; Kinoshita, Akihide; Nagai, Tatsuya; Natsubori, Tatsunobu; Tada, Mariko; Ichikawa, Eriko; Takizawa, Ryu; Kasai, Kiyoto

    2016-02-01

    Few biomarkers can be used easily and noninvasively to measure clinical condition and future outcome in patients with first-episode psychosis (FEP). To develop such biomarker using multichannel functional near-infrared spectroscopy (fNIRS), cortical function in the prefrontal cortex was longitudinally measured during a verbal fluency task. Sixty-nine fNIRS measurements and 77 clinical assessments were obtained from 31 patients with FEP at baseline, 6-month, and 12-month follow-ups. Sixty measurements were obtained from 30 healthy controls matched for age, sex, and premorbid IQ. We initially tested signal changes for 12 months, and then investigated the relationship between fNIRS signals and clinical assessments. Signal changes from baseline to 12-month follow-up were not evident in any group. Patients with FEP had significant positive correlation coefficients between 6-month fNIRS signals and the 12-month Global Assessment of Functioning (GAF) score in the left middle frontal gyrus (FDR-corrected p=.0016-.0052, r=.65-.59). fNIRS signals at the 12-month follow-up were associated with 12-month GAF score in the bilateral superior and middle frontal gyri (FDR-corrected p=.00085-.018, r=.72-.55), and with the difference between baseline and 12-month GAF scores in the right superior frontal gyrus (FDR-corrected p=.000067-.00012, r=.80-.78). These associations were significant even after controlling for demographic variables. No association between baseline fNIRS signals and later GAF scores was found. fNIRS measurement can potentially be used as a biomarker to aid sequential assessment of neuro-clinical conditions through the early stage of psychosis. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Impairment of preoperative language mapping by lesion location: a functional magnetic resonance imaging, navigated transcranial magnetic stimulation, and direct cortical stimulation study.

    Science.gov (United States)

    Ille, Sebastian; Sollmann, Nico; Hauck, Theresa; Maurer, Stefanie; Tanigawa, Noriko; Obermueller, Thomas; Negwer, Chiara; Droese, Doris; Boeckh-Behrens, Tobias; Meyer, Bernhard; Ringel, Florian; Krieg, Sandro M

    2015-08-01

    Language mapping by repetitive navigated transcranial magnetic stimulation (rTMS) is increasingly used and has already replaced functional MRI (fMRI) in some institutions for preoperative mapping of neurosurgical patients. Yet some factors affect the concordance of both methods with direct cortical stimulation (DCS), most likely by lesions affecting cortical oxygenation levels. Therefore, the impairment of the accuracy of rTMS and fMRI was analyzed and compared with DCS during awake surgery in patients with intraparenchymal lesions. Language mapping was performed by DCS, rTMS, and fMRI using an object-naming task in 27 patients with left-sided perisylvian lesions, and the induced language errors of each method were assigned to the cortical parcellation system. Subsequently, the receiver operating characteristics were calculated for rTMS and fMRI and compared with DCS as ground truth for regions with (w/) and without (w/o) the lesion in the mapped regions. The w/ subgroup revealed a sensitivity of 100% (w/o 100%), a specificity of 8% (w/o 5%), a positive predictive value of 34% (w/o: 53%), and a negative predictive value (NPV) of 100% (w/o: 100%) for the comparison of rTMS versus DCS. Findings for the comparison of fMRI versus DCS within the w/ subgroup revealed a sensitivity of 32% (w/o: 62%), a specificity of 88% (w/o: 60%), a positive predictive value of 56% (w/o: 62%), and a NPV of 73% (w/o: 60%). Although strengths and weaknesses exist for both rTMS and fMRI, the results show that rTMS is less affected by a brain lesion than fMRI, especially when performing mapping of language-negative cortical regions based on sensitivity and NPV.

  5. Domiciliary VR-Based Therapy for Functional Recovery and Cortical Reorganization: Randomized Controlled Trial in Participants at the Chronic Stage Post Stroke.

    Science.gov (United States)

    Ballester, Belén Rubio; Nirme, Jens; Camacho, Irene; Duarte, Esther; Rodríguez, Susana; Cuxart, Ampar; Duff, Armin; Verschure, Paul F M J

    2017-08-07

    Most stroke survivors continue to experience motor impairments even after hospital discharge. Virtual reality-based techniques have shown potential for rehabilitative training of these motor impairments. Here we assess the impact of at-home VR-based motor training on functional motor recovery, corticospinal excitability and cortical reorganization. The aim of this study was to identify the effects of home-based VR-based motor rehabilitation on (1) cortical reorganization, (2) corticospinal tract, and (3) functional recovery after stroke in comparison to home-based occupational therapy. We conducted a parallel-group, controlled trial to compare the effectiveness of domiciliary VR-based therapy with occupational therapy in inducing motor recovery of the upper extremities. A total of 35 participants with chronic stroke underwent 3 weeks of home-based treatment. A group of subjects was trained using a VR-based system for motor rehabilitation, while the control group followed a conventional therapy. Motor function was evaluated at baseline, after the intervention, and at 12-weeks follow-up. In a subgroup of subjects, we used Navigated Brain Stimulation (NBS) procedures to measure the effect of the interventions on corticospinal excitability and cortical reorganization. Results from the system's recordings and clinical evaluation showed significantly greater functional recovery for the experimental group when compared with the control group (1.53, SD 2.4 in Chedoke Arm and Hand Activity Inventory). However, functional improvements did not reach clinical significance. After the therapy, physiological measures obtained from a subgroup of subjects revealed an increased corticospinal excitability for distal muscles driven by the pathological hemisphere, that is, abductor pollicis brevis. We also observed a displacement of the centroid of the cortical map for each tested muscle in the damaged hemisphere, which strongly correlated with improvements in clinical scales. These

  6. Os efeitos da estimulação elétrica funcional na assimetria cortical inter-hemisférica The effects of functional electrical stimulation on cortical interhemispheric asymmetry

    Directory of Open Access Journals (Sweden)

    Letícia Ecard

    2007-09-01

    Full Text Available O objetivo do presente estudo foi avaliar os efeitos da estimulação elétrica funcional na assimetria cortical inter-hemisférica. Para tal, simultaneamente ao registro da atividade eletroencefalográfica, realizou-se eletroestimulação no antebraço direito para estimulação da extensão do indicador. A amostra consistiu de 45 sujeitos randomizados em 3 grupos de 15 sujeitos cada: grupo controle (submetido a 24 blocos de estimulação com intensidade de corrente zero, grupo 1 (24 blocos e grupo 2 (36 blocos. A assimetria entre os pares de eletrodos F3-F4, C3-C4 e P3-P4 foi analisada ao longo dos grupos através de uma Anova. Os resultados apontaram para uma interação grupo x eletrodo e uma tendência de diminuição da assimetria inter-hemisférica após a eletroestimulação.The aim of the present study was to assess the effects of functional electrical stimulation (FES on cortical interhemispheric asymmetry. Electrostimulation was performed on the right forearm to stimulate the extension of the index finger. EEG activity was recorded simultaneously. The sample included 45 subjects randomly divided into 3 groups of 15 subjects each: control group (submitted to 24 blocks of stimulation at a null intensity current, group 1 (24 blocks and group 2 (36 blocks. Interhemispheric asymmetry between F3-F4, C3-C4 and P3-P4 was analyzed through an Anova. Results pointed out to a group x electrode interaction and a general tendency of asymmetry decrease after stimulation.

  7. Combined DTI Tractography and Functional MRI Study of the Language Connectome in Healthy Volunteers: Extensive Mapping of White Matter Fascicles and Cortical Activations.

    Science.gov (United States)

    Vassal, François; Schneider, Fabien; Boutet, Claire; Jean, Betty; Sontheimer, Anna; Lemaire, Jean-Jacques

    2016-01-01

    Despite a better understanding of brain language organization into large-scale cortical networks, the underlying white matter (WM) connectivity is still not mastered. Here we combined diffusion tensor imaging (DTI) fiber tracking (FT) and language functional magnetic resonance imaging (fMRI) in twenty healthy subjects to gain new insights into the macroscopic structural connectivity of language. Eight putative WM fascicles for language were probed using a deterministic DTI-FT technique: the arcuate fascicle (AF), superior longitudinal fascicle (SLF), uncinate fascicle (UF), temporo-occipital fascicle, inferior fronto-occipital fascicle (IFOF), middle longitudinal fascicle (MdLF), frontal aslant fascicle and operculopremotor fascicle. Specific measurements (i.e. volume, length, fractional anisotropy) and precise cortical terminations were derived for each WM fascicle within both hemispheres. Connections between these WM fascicles and fMRI activations were studied to determine which WM fascicles are related to language. WM fascicle volumes showed asymmetries: leftward for the AF, temporoparietal segment of SLF and UF, and rightward for the frontoparietal segment of the SLF. The lateralization of the AF, IFOF and MdLF extended to differences in patterns of anatomical connections, which may relate to specific hemispheric abilities. The leftward asymmetry of the AF was correlated to the leftward asymmetry of fMRI activations, suggesting that the lateralization of the AF is a structural substrate of hemispheric language dominance. We found consistent connections between fMRI activations and terminations of the eight WM fascicles, providing a detailed description of the language connectome. WM fascicle terminations were also observed beyond fMRI-confirmed language areas and reached numerous cortical areas involved in different functional brain networks. These findings suggest that the reported WM fascicles are not exclusively involved in language and might be related to

  8. Intraoperative cortico-cortical evoked potentials for the evaluation of language function during brain tumor resection: initial experience with 13 cases.

    Science.gov (United States)

    Saito, Taiichi; Tamura, Manabu; Muragaki, Yoshihiro; Maruyama, Takashi; Kubota, Yuichi; Fukuchi, Satoko; Nitta, Masayuki; Chernov, Mikhail; Okamoto, Saori; Sugiyama, Kazuhiko; Kurisu, Kaoru; Sakai, Kuniyoshi L; Okada, Yoshikazu; Iseki, Hiroshi

    2014-10-01

    The objective in the present study was to evaluate the usefulness of cortico-cortical evoked potentials (CCEP) monitoring for the intraoperative assessment of speech function during resection of brain tumors. Intraoperative monitoring of CCEP was applied in 13 patients (mean age 34 ± 14 years) during the removal of neoplasms located within or close to language-related structures in the dominant cerebral hemisphere. For this purpose strip electrodes were positioned above the frontal language area (FLA) and temporal language area (TLA), which were identified with direct cortical stimulation and/or preliminary mapping with the use of implanted chronic subdural grid electrodes. The CCEP response was defined as the highest observed negative peak in either direction of stimulation. In 12 cases the tumor was resected during awake craniotomy. An intraoperative CCEP response was not obtained in one case because of technical problems. In the other patients it was identified from the FLA during stimulation of the TLA (7 cases) and from the TLA during stimulation of the FLA (5 cases), with a mean peak latency of 83 ± 15 msec. During tumor resection the CCEP response was unchanged in 5 cases, decreased in 4, and disappeared in 3. Postoperatively, all 7 patients with a decreased or absent CCEP response after lesion removal experienced deterioration in speech function. In contrast, in 5 cases with an unchanged intraoperative CCEP response, speaking abilities after surgery were preserved at the preoperative level, except in one patient who experienced not dysphasia, but dysarthria due to pyramidal tract injury. This difference was statistically significant (p brain tumors affecting language-related cerebral structures. In the intraoperative evaluation of speech function, it can be a helpful adjunct or can be used in its direct assessment with cortical and subcortical mapping during awake craniotomy. It can also be used to predict the prognosis of language disorders after surgery

  9. Is preoperative functional magnetic resonance imaging reliable for language areas mapping in brain tumor surgery? Review of language functional magnetic resonance imaging and direct cortical stimulation correlation studies.

    Science.gov (United States)

    Giussani, Carlo; Roux, Frank-Emmanuel; Ojemann, Jeffrey; Sganzerla, Erik Pietro; Pirillo, David; Papagno, Costanza

    2010-01-01

    Language functional magnetic resonance imaging (fMRI) has been used extensively in the past decade for both clinical and research purposes. Its integration in the preoperative imaging assessment of brain lesions involving eloquent areas is progressively more diffused in neurosurgical practice. Nevertheless, the reliability of language fMRI is unclear. To understand the reliability of preoperative language fMRI in patients operated on for brain tumors, the surgical studies that compared language fMRI with direct cortical stimulation (DCS) were reviewed. Articles comparing language fMRI with DCS of language areas were reviewed with attention to the lesion pathology, the magnetic field, the language tasks used pre- and intraoperatively, and the validation modalities adopted to establish the reliability of language fMRI. We tried to explore the effectiveness of language fMRI in gliomas. Nine language brain mapping studies compared the findings of fMRI with those of DCS. The studies are not homogeneous for tumor types, magnetic fields, pre- and intraoperative language tasks, intraoperative matching criteria, and results. Sensitivity and specificity were calculated in 5 studies (respectively ranging from 59% to 100% and from 0% to 97%). The contradictory results of these studies do not allow consideration of language fMRI as an alternative tool to DCS in brain lesions located in language areas, especially in gliomas because of the pattern of growth of these tumors. However, language fMRI conducted with high magnet fields is a promising brain mapping tool that must be validated by DCS in methodological robust studies.

  10. Sensory Gain Outperforms Efficient Readout Mechanisms in Predicting Attention-Related Improvements in Behavior

    Science.gov (United States)

    Ester, Edward F.; Deering, Sean

    2014-01-01

    Spatial attention has been postulated to facilitate perceptual processing via several different mechanisms. For instance, attention can amplify neural responses in sensory areas (sensory gain), mediate neural variability (noise modulation), or alter the manner in which sensory signals are selectively read out by postsensory decision mechanisms (efficient readout). Even in the context of simple behavioral tasks, it is unclear how well each of these mechanisms can account for the relationship between attention-modulated changes in behavior and neural activity because few studies have systematically mapped changes between stimulus intensity, attentional focus, neural activity, and behavioral performance. Here, we used a combination of psychophysics, event-related potentials (ERPs), and quantitative modeling to explicitly link attention-related changes in perceptual sensitivity with changes in the ERP amplitudes recorded from human observers. Spatial attention led to a multiplicative increase in the amplitude of an early sensory ERP component (the P1, peaking ∼80–130 ms poststimulus) and in the amplitude of the late positive deflection component (peaking ∼230–330 ms poststimulus). A simple model based on signal detection theory demonstrates that these multiplicative gain changes were sufficient to account for attention-related improvements in perceptual sensitivity, without a need to invoke noise modulation. Moreover, combining the observed multiplicative gain with a postsensory readout mechanism resulted in a significantly poorer description of the observed behavioral data. We conclude that, at least in the context of relatively simple visual discrimination tasks, spatial attention modulates perceptual sensitivity primarily by modulating the gain of neural responses during early sensory processing PMID:25274817

  11. Dysfunction and dysconnection in cortical-striatal networks during sustained attention: Genetic risk for schizophrenia or bipolar disorder and its impact on brain network function

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    Vaibhav A. Diwadkar

    2014-05-01

    Full Text Available Abnormalities in the brain’s attention network may represent early identifiable neurobiological impairments in individuals at increased risk for schizophrenia or bipolar disorder. Here we provide evidence of dysfunctional regional and network function in adolescents at higher genetic risk for schizophrenia or bipolar disorder (henceforth HGR. During fMRI, participants engaged in a sustained attention task with variable demands. The task alternated between attention (120 s, visual control (passive viewing; 120 s and rest (20 s epochs. Low and high demand attention conditions were created using the rapid presentation of 2- or 3-digit numbers. Subjects were required to detect repeated presentation of numbers. We demonstrate that the recruitment of cortical and striatal regions are disordered in HGR: Relative to typical controls (TC, HGR showed lower recruitment of the dorsal prefrontal cortex, but higher recruitment of the superior parietal cortex. This imbalance was more dramatic in the basal ganglia. There, a group by task demand interaction was observed, such that increased attention demand led to increased engagement in TC, but disengagement in HGR. These activation studies were complemented by network analyses using Dynamic Causal Modeling. Competing model architectures were assessed across a network of cortical-striatal regions, distinguished at a second level using random effects Bayesian model selection. In the winning architecture, HGR were characterized by significant reductions in coupling across both frontal-striatal and frontal-parietal pathways. The effective connectivity analyses indicate emergent network dysconnection, consistent with findings in patients with schizophrenia. Emergent patterns of regional dysfunction and disconnection in cortical-striatal pathways may provide functional biological signatures in the adolescent risk state for psychiatric illness.

  12. Cortical Visual Impairment

    Science.gov (United States)

    ... Frequently Asked Questions Español Condiciones Chinese Conditions Cortical Visual Impairment En Español Read in Chinese What is cortical visual impairment? Cortical visual impairment (CVI) is a decreased ...

  13. Prevalence, and Intellectual Outcome of Unilateral Focal Cortical Brain Damage as a Function of Age, Sex and Aetiology

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    C. M. J. Braun

    2002-01-01

    Full Text Available Neurologists and neuropsychologists are aware that aging men are more at risk than women for brain damage, principally because of the well known male-predominant risk for cardiovascular disease and related cerebrovascular accidents. However, a disproportion in prevalence of brain damage between the sexes in childhood may be less suspected. Furthermore, sex-specific risk for other aetiologies of brain damage may be little known, whether in the pediatric or adult populations. Proposals of a sex difference in cognitive recovery from brain damage have also been controversial. Six hundred and thirty five “consecutive” cases with cortical focal lesions including cases of all ages and both sexes were reviewed. Aetiology of the lesion was determined for each case as was postlesion IQ. Risk was highly male prevalent in all age groups, with a predominance of cardiovascular aetiology explaining much of the adult male prevalence. However, several other aetiological categories were significantly male prevalent in juveniles (mitotic, traumatic, dysplasic and adults (mitotic, traumatic. There was no sex difference in outcome (i.e., postlesion IQ of these cortical brain lesions for the cohort as a whole, after statistical removal of the influence of lesion extent, aetiology and presence of epilepsy. Mechanisms potentially responsible for sex differences in prevalence, aetiology of brain damage, and recovery, are reviewed and discussed.

  14. Trail making test performance in youth varies as a function of anatomical coupling between the prefrontal cortex and distributed cortical regions

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    Nancy Raitano Lee

    2014-07-01

    Full Text Available While researchers have gained a richer understanding of the neural correlates of executive function in adulthood, much less is known about how these abilities are represented in the developing brain and what structural brain networks underlie them. Thus, the current study examined how individual differences in executive function, as measured by the Trail Making Test (TMT, relate to structural covariance in the pediatric brain. The sample included 146 unrelated, typically developing youth (80 females, ages 9-14 years, who completed a structural MRI scan of the brain and the Halstead-Reitan TMT (intermediate form. TMT scores used to index executive function included those that evaluated set-shifting ability: Trails B time (number-letter sequencing and the difference in time between Trails B and A (number sequencing only. Anatomical coupling was measured by examining correlations between mean cortical thickness (MCT across the entire cortical ribbon and individual vertex thickness measured at ~81,000 vertices. To examine how TMT scores related to anatomical coupling strength, linear regression was utilized and the interaction between age-normed TMT scores and both age and sex-normed MCT was used to predict vertex thickness. Results revealed that stronger Trails B scores were associated with greater anatomical coupling between a large swath of prefrontal cortex and the rest of cortex. For the difference between Trails B and A, a network of regions in the frontal, temporal and parietal lobes was found to be more tightly coupled with the rest of cortex in stronger performers. This study is the first to highlight the importance of structural covariance in the prediction of individual differences in executive function skills in youth. Thus, it adds to the growing literature on the neural correlates of childhood executive functions and identifies neuroanatomic coupling as a biological substrate that may contribute to executive function and dysfunction in

  15. Enhancing motor performance improvement by personalizing non-invasive cortical stimulation with concurrent functional near-infrared spectroscopy and multi-modal motor measurements

    Science.gov (United States)

    Khan, Bilal; Hodics, Timea; Hervey, Nathan; Kondraske, George; Stowe, Ann; Alexandrakis, George

    2015-03-01

    Transcranial direct current stimulation (tDCS) is a non-invasive cortical stimulation technique that can facilitate task specific plasticity that can improve motor performance. Current tDCS interventions uniformly apply a chosen electrode montage to a subject population without personalizing electrode placement for optimal motor gains. We propose a novel perturbation tDCS (ptDCS) paradigm for determining a personalized electrode montage in which tDCS intervention yields maximal motor performance improvements during stimulation. PtDCS was applied to ten healthy adults and five stroke patients with upper hemiparesis as they performed an isometric wrist flexion task with their non-dominant arm. Simultaneous recordings of torque applied to a stationary handle, muscle activity by electromyography (EMG), and cortical activity by functional near-infrared spectroscopy (fNIRS) during ptDCS helped interpret how cortical activity perturbations by any given electrode montage related to changes in muscle activity and task performance quantified by a Reaction Time (RT) X Error product. PtDCS enabled quantifying the effect on task performance of 20 different electrode pair montages placed over the sensorimotor cortex. Interestingly, the electrode montage maximizing performance in all healthy adults did not match any of the ones being explored in current literature as a means of improving the motor performance of stroke patients. Furthermore, the optimal montage was found to be different in each stroke patient and the resulting motor gains were very significant during stimulation. This study supports the notion that task-specific ptDCS optimization can lend itself to personalizing the rehabilitation of patients with brain injury.

  16. Predictive timing functions of cortical beta oscillations are impaired in Parkinson's disease and influenced by L-DOPA and deep brain stimulation of the subthalamic nucleus

    Directory of Open Access Journals (Sweden)

    A. Gulberti

    2015-01-01

    Full Text Available Cortex-basal ganglia circuits participate in motor timing and temporal perception, and are important for the dynamic configuration of sensorimotor networks in response to exogenous demands. In Parkinson's disease (PD patients, rhythmic auditory stimulation (RAS induces motor performance benefits. Hitherto, little is known concerning contributions of the basal ganglia to sensory facilitation and cortical responses to RAS in PD. Therefore, we conducted an EEG study in 12 PD patients before and after surgery for subthalamic nucleus deep brain stimulation (STN-DBS and in 12 age-matched controls. Here we investigated the effects of levodopa and STN-DBS on resting-state EEG and on the cortical-response profile to slow and fast RAS in a passive-listening paradigm focusing on beta-band oscillations, which are important for auditory–motor coupling. The beta-modulation profile to RAS in healthy participants was characterized by local peaks preceding and following auditory stimuli. In PD patients RAS failed to induce pre-stimulus beta increases. The absence of pre-stimulus beta-band modulation may contribute to impaired rhythm perception in PD. Moreover, post-stimulus beta-band responses were highly abnormal during fast RAS in PD patients. Treatment with levodopa and STN-DBS reinstated a post-stimulus beta-modulation profile similar to controls, while STN-DBS reduced beta-band power in the resting-state. The treatment-sensitivity of beta oscillations suggests that STN-DBS may specifically improve timekeeping functions of cortical beta oscillations during fast auditory pacing.

  17. Neonatal mouse cortical but not isogenic human astrocyte feeder layers enhance the functional maturation of induced pluripotent stem cell-derived neurons in culture.

    Science.gov (United States)

    Lischka, Fritz W; Efthymiou, Anastasia; Zhou, Qiong; Nieves, Michael D; McCormack, Nikki M; Wilkerson, Matthew D; Sukumar, Gauthaman; Dalgard, Clifton L; Doughty, Martin L

    2018-04-01

    Human induced pluripotent stem (iPS) cell-derived neurons and astrocytes are attractive cellular tools for nervous system disease modeling and drug screening. Optimal utilization of these tools requires differentiation protocols that efficiently generate functional cell phenotypes in vitro. As nervous system function is dependent on networked neuronal activity involving both neuronal and astrocytic synaptic functions, we examined astrocyte effects on the functional maturation of neurons from human iPS cell-derived neural stem cells (NSCs). We first demonstrate human iPS cell-derived NSCs can be rapidly differentiated in culture to either neurons or astrocytes with characteristic cellular, molecular and physiological features. Although differentiated neurons were capable of firing multiple action potentials (APs), few cells developed spontaneous electrical activity in culture. We show spontaneous electrical activity was significantly increased by neuronal differentiation of human NSCs on feeder layers of neonatal mouse cortical astrocytes. In contrast, co-culture on feeder layers of isogenic human iPS cell-derived astrocytes had no positive effect on spontaneous neuronal activity. Spontaneous electrical activity was dependent on glutamate receptor-channel function and occurred without changes in I Na , I K , V m , and AP properties of iPS cell-derived neurons. These data demonstrate co-culture with neonatal mouse cortical astrocytes but not human isogenic iPS cell-derived astrocytes stimulates glutamatergic synaptic transmission between iPS cell-derived neurons in culture. We present RNA-sequencing data for an immature, fetal-like status of our human iPS cell-derived astrocytes as one possible explanation for their failure to enhance synaptic activity in our co-culture system. © 2017 Wiley Periodicals, Inc.

  18. Recording human electrocorticographic (ECoG) signals for neuroscientific research and real-time functional cortical mapping.

    Science.gov (United States)

    Hill, N Jeremy; Gupta, Disha; Brunner, Peter; Gunduz, Aysegul; Adamo, Matthew A; Ritaccio, Anthony; Schalk, Gerwin

    2012-06-26

    Neuroimaging studies of human cognitive, sensory, and motor processes are usually based on noninvasive techniques such as electroencephalography (EEG), magnetoencephalography or functional magnetic-resonance imaging. These techniques have either inherently low temporal or low spatial resolution, and suffer from low signal-to-noise ratio and/or poor high-frequency sensitivity. Thus, they are suboptimal for exploring the short-lived spatio-temporal dynamics of many of the underlying brain processes. In contrast, the invasive technique of electrocorticography (ECoG) provides brain signals that have an exceptionally high signal-to-noise ratio, less susceptibility to artifacts than EEG, and a high spatial and temporal resolution (i.e., communication and control. Nevertheless, human ECoG data are often hard to obtain because of the risks and limitations of the invasive procedures involved, and the need to record within the constraints of clinical settings. Still, clinical monitoring to localize epileptic foci offers a unique and valuable opportunity to collect human ECoG data. We describe our methods for collecting recording ECoG, and demonstrate how to use these signals for important real-time applications such as clinical mapping and brain-computer interfacing. Our example uses the BCI2000 software platform and the SIGFRIED method, an application for real-time mapping of brain functions. This procedure yields information that clinicians can subsequently use to guide the complex and laborious process of functional mapping by electrical stimulation. PREREQUISITES AND PLANNING: Patients with drug-resistant partial epilepsy may be candidates for resective surgery of an epileptic focus to minimize the frequency of seizures. Prior to resection, the patients undergo monitoring using subdural electrodes for two purposes: first, to localize the epileptic focus, and second, to identify nearby critical brain areas (i.e., eloquent cortex) where resection could result in long

  19. Probing the corticospinal link between the motor cortex and motoneurones: some neglected aspects of human motor cortical function

    DEFF Research Database (Denmark)

    Petersen, Nicolas Caesar; Butler, Jane E.; Taylor, Janet L.

    2010-01-01

    ABSTRACT This review considers the operation of the corticospinal system in primates. There is a relatively widespread cortical area containing corticospinal outputs to a single muscle and thus a motoneurone pool receives corticospinal input from a wide region of cortex. In addition, corticospinal...... cells themselves have divergent intraspinal branches which innervate more than one motoneuronal pool but the synergistic couplings involving the many hand muscles are likely to be more diverse than can be accommodated simply by fixed patterns of corticospinal divergence. Many studies using transcranial...... of the discharge of motor units have revealed that the rapidly conducting corticospinal axons (stimulated at higher intensities) contribute to drive motoneurones in normal voluntary contractions. There are also major non-linearities generated at a spinal level in the relation between corticospinal output...

  20. Improvement of spasticity following intermittent theta burst stimulation in multiple sclerosis is associated with modulation of resting-state functional connectivity of the primary motor cortices.

    Science.gov (United States)

    Boutière, Clémence; Rey, Caroline; Zaaraoui, Wafaa; Le Troter, Arnaud; Rico, Audrey; Crespy, Lydie; Achard, Sophie; Reuter, Françoise; Pariollaud, Fanelly; Wirsich, Jonathan; Asquinazi, Patrick; Confort-Gouny, Sylviane; Soulier, Elisabeth; Guye, Maxime; Pelletier, Jean; Ranjeva, Jean-Philippe; Audoin, Bertrand

    2017-05-01

    Intermittent theta burst stimulation (iTBS) of the primary motor cortex improves transiently lower limbs spasticity in multiple sclerosis (MS). However, the cerebral mechanisms underlying this effect have never been investigated. To assess whether modulation of spasticity induced by iTBS is underlined by functional reorganization of the primary motor cortices. A total of 17 patients with MS suffering from lower limbs spasticity were randomized to receive real iTBS or sham iTBS during the first half of a 5-week indoor rehabilitation programme. Spasticity was assessed using the Modified Ashworth Scale and the Visual Analogue Scale at baseline, after the stimulation session and at the end of the rehabilitation programme. Resting-state functional magnetic resonance imaging (fMRI) was performed at the three time points, and brain functional networks topology was analysed using graph-theoretical approach. At the end of stimulation, improvement of spasticity was greater in real iTBS group than in sham iTBS group ( p = 0.026). iTBS had a significant effect on the balance of the connectivity degree between the stimulated and the homologous primary motor cortex ( p = 0.005). Changes in inter-hemispheric balance were correlated with improvement of spasticity (rho = 0.56, p = 0.015). This longitudinal resting-state fMRI study evidences that functional reorganization of the primary motor cortices may underlie the effect of iTBS on spasticity in MS.

  1. Human Auditory and Adjacent Nonauditory Cerebral Cortices Are Hypermetabolic in Tinnitus as Measured by Functional Near-Infrared Spectroscopy (fNIRS).

    Science.gov (United States)

    Issa, Mohamad; Bisconti, Silvia; Kovelman, Ioulia; Kileny, Paul; Basura, Gregory J

    2016-01-01

    Tinnitus is the phantom perception of sound in the absence of an acoustic stimulus. To date, the purported neural correlates of tinnitus from animal models have not been adequately characterized with translational technology in the human brain. The aim of the present study was to measure changes in oxy-hemoglobin concentration from regions of interest (ROI; auditory cortex) and non-ROI (adjacent nonauditory cortices) during auditory stimulation and silence in participants with subjective tinnitus appreciated equally in both ears and in nontinnitus controls using functional near-infrared spectroscopy (fNIRS). Control and tinnitus participants with normal/near-normal hearing were tested during a passive auditory task. Hemodynamic activity was monitored over ROI and non-ROI under episodic periods of auditory stimulation with 750 or 8000 Hz tones, broadband noise, and silence. During periods of silence, tinnitus participants maintained increased hemodynamic responses in ROI, while a significant deactivation was seen in controls. Interestingly, non-ROI activity was also increased in the tinnitus group as compared to controls during silence. The present results demonstrate that both auditory and select nonauditory cortices have elevated hemodynamic activity in participants with tinnitus in the absence of an external auditory stimulus, a finding that may reflect basic science neural correlates of tinnitus that ultimately contribute to phantom sound perception.

  2. Human Auditory and Adjacent Nonauditory Cerebral Cortices Are Hypermetabolic in Tinnitus as Measured by Functional Near-Infrared Spectroscopy (fNIRS

    Directory of Open Access Journals (Sweden)

    Mohamad Issa

    2016-01-01

    Full Text Available Tinnitus is the phantom perception of sound in the absence of an acoustic stimulus. To date, the purported neural correlates of tinnitus from animal models have not been adequately characterized with translational technology in the human brain. The aim of the present study was to measure changes in oxy-hemoglobin concentration from regions of interest (ROI; auditory cortex and non-ROI (adjacent nonauditory cortices during auditory stimulation and silence in participants with subjective tinnitus appreciated equally in both ears and in nontinnitus controls using functional near-infrared spectroscopy (fNIRS. Control and tinnitus participants with normal/near-normal hearing were tested during a passive auditory task. Hemodynamic activity was monitored over ROI and non-ROI under episodic periods of auditory stimulation with 750 or 8000 Hz tones, broadband noise, and silence. During periods of silence, tinnitus participants maintained increased hemodynamic responses in ROI, while a significant deactivation was seen in controls. Interestingly, non-ROI activity was also increased in the tinnitus group as compared to controls during silence. The present results demonstrate that both auditory and select nonauditory cortices have elevated hemodynamic activity in participants with tinnitus in the absence of an external auditory stimulus, a finding that may reflect basic science neural correlates of tinnitus that ultimately contribute to phantom sound perception.

  3. Tactile stimulation after frontal or parietal cortical injury in infant rats facilitates functional recovery and produces synaptic changes in adjacent cortex.

    Science.gov (United States)

    Kolb, Bryan; Gibb, Robbin

    2010-12-06

    Rats with bilateral lesions (and sham controls) of the medial frontal or posterior parietal cortex on postnatal days 2-4 were treated with tactile stimulation for 15min three times daily for two weeks following injury. In adulthood they were trained in a spatial navigation task and a skilled reaching task, their brains were removed, and dendritic length and spine density were analyzed in layer III pyramidal neurons in area Par 1. Tactile stimulation significantly reduced the behavioral impairments after early cortical injury. Neonatal lesions decreased dendritic length and this was reversed by stimulation in rats with parietal, but not frontal, lesions. Both lesions decreased spine density and tactile stimulation reversed this loss in frontal but not parietal lesion animals. In addition, tactile stimulation decreased spine density in control animals. The results suggest that early intervention with tactile stimulation after cortical injury may be important for stimulating plastic changes in the cortex that can underlie functional recovery and that different mechanisms of synaptic change may occur after different injuries. Copyright 2010 Elsevier B.V. All rights reserved.

  4. CB1 augments mGluR5 function in medial prefrontal cortical neurons to inhibit amygdala hyperactivity in an arthritis pain model.

    Science.gov (United States)

    Ji, Guangchen; Neugebauer, Volker

    2014-02-01

    The medial prefrontal cortex (mPFC) serves executive control functions and forms direct connections with subcortical areas such as the amygdala. Our previous work showed abnormal inhibition of mPFC pyramidal cells and hyperactivity of amygdala output neurons in an arthritis pain model. To restore mPFC activity and hence control pain-related amygdala hyperactivity this study focused on CB1 and mGluR5 receptors, which are important modulators of cortical functions. Extracellular single-unit recordings of infralimbic mPFC pyramidal cells and of amygdala output neurons in the laterocapsular division of the central nucleus (CeLC) were made in anesthetised adult male rats. mPFC neurons were classified as 'excited' or 'inhibited' based on their response to brief innocuous and noxious test stimuli. After arthritis pain induction, background activity and evoked responses of excited neurons and background activity and inhibition of inhibited neurons decreased. Stereotaxic application of an mGluR5-positive allosteric modulator (N-cyclobutyl-6-((3-fluorophenyl)ethynyl) nicotinamide hydrochloride, VU0360172) into the mPFC increased background and evoked activity of excited, but not inhibited, mPFC neurons under normal conditions but not in arthritis. A selective CB1 receptor agonist (arachidonyl-2-chloroethylamide) alone had no effect but restored the facilitatory effects of VU0360172 in the pain model. Coactivation of CB1 and mGluR5 in the mPFC inhibited the pain-related activity increase of CeLC neurons but had no effect under normal conditions. The data suggest that excited mPFC neurons are inversely linked to amygdala output (CeLC) and that CB1 can increase mGluR5 function in this subset of mPFC neurons to engage cortical control of abnormally enhanced amygdala output in pain. © 2014 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  5. Reward- and attention-related biasing of sensory selection in visual cortex.

    Science.gov (United States)

    Buschschulte, Antje; Boehler, Carsten N; Strumpf, Hendrik; Stoppel, Christian; Heinze, Hans-Jochen; Schoenfeld, Mircea A; Hopf, Jens-Max

    2014-05-01

    Attention to task-relevant features leads to a biasing of sensory selection in extrastriate cortex. Features signaling reward seem to produce a similar bias, but how modulatory effects due to reward and attention relate to each other is largely unexplored. To address this issue, it is critical to separate top-down settings defining reward relevance from those defining attention. To this end, we used a visual search paradigm in which the target's definition (attention to color) was dissociated from reward relevance by delivering monetary reward on search frames where a certain task-irrelevant color was combined with the target-defining color to form the target object. We assessed the state of neural biasing for the attended and reward-relevant color by analyzing the neuromagnetic brain response to asynchronously presented irrelevant distractor probes drawn in the target-defining color, the reward-relevant color, and a completely irrelevant color as a reference. We observed that for the prospect of moderate rewards, the target-defining color but not the reward-relevant color produced a selective enhancement of the neuromagnetic response between 180 and 280 msec in ventral extrastriate visual cortex. Increasing reward prospect caused a delayed attenuation (220-250 msec) of the response to reward probes, which followed a prior (160-180 msec) response enhancement in dorsal ACC. Notably, shorter latency responses in dorsal ACC were associated with stronger attenuation in extrastriate visual cortex. Finally, an analysis of the brain response to the search frames revealed that the presence of the reward-relevant color in search distractors elicited an enhanced response that was abolished after increasing reward size. The present data together indicate that when top-down definitions of reward relevance and attention are separated, the behavioral significance of reward-associated features is still rapidly coded in higher-level cortex areas, thereby commanding effective top

  6. Cortical visual impairment

    OpenAIRE

    Koželj, Urša

    2013-01-01

    In this thesis we discuss cortical visual impairment, diagnosis that is in the developed world in first place, since 20 percent of children with blindness or low vision are diagnosed with it. The objectives of the thesis are to define cortical visual impairment and the definition of characters suggestive of the cortical visual impairment as well as to search for causes that affect the growing diagnosis of cortical visual impairment. There are a lot of signs of cortical visual impairment. ...

  7. Age-dependent effect of apolipoprotein E4 on functional outcome after controlled cortical impact in mice.

    Science.gov (United States)

    Mannix, Rebekah C; Zhang, Jimmy; Park, Juyeon; Zhang, Xuan; Bilal, Kiran; Walker, Kendall; Tanzi, Rudolph E; Tesco, Giuseppina; Whalen, Michael J

    2011-01-01

    The apolipoprotein E4 (APOE4) gene leads to increased brain amyloid beta (Aβ) and poor outcome in adults with traumatic brain injury (TBI); however, its role in childhood TBI is controversial. We hypothesized that the transgenic expression of human APOE4 worsens the outcome after controlled cortical impact (CCI) in adult but not immature mice. Adult and immature APOE4 mice had worse motor outcome after CCI (P<0.001 versus wild type (WT)), but the Morris water maze performance was worse only in adult APOE4 mice (P=0.028 at 2 weeks, P=0.019 at 6 months versus WT), because immature APOE4 mice had performance similar to WT for up to 1 year after injury. Brain lesion size was similar in adult APOE4 mice but was decreased (P=0.029 versus WT) in injured immature APOE4 mice. Microgliosis was similar in all groups. Soluble brain Aβ(40) was increased at 48 hours after CCI in adult and immature APOE4 mice and in adult WT (P<0.05), and was dynamically regulated during the chronic period by APOE4 in adults but not immature mice. The data suggest age-dependent effects of APOE4 on cognitive outcome after TBI, and that therapies targeting APOE4 may be more effective in adults versus children with TBI.

  8. Age-dependent effect of apolipoprotein E4 on functional outcome after controlled cortical impact in mice

    Science.gov (United States)

    Mannix, Rebekah C; Zhang, Jimmy; Park, Juyeon; Zhang, Xuan; Bilal, Kiran; Walker, Kendall; Tanzi, Rudolph E; Tesco, Giuseppina; Whalen, Michael J

    2011-01-01

    The apolipoprotein E4 (APOE4) gene leads to increased brain amyloid beta (Aβ) and poor outcome in adults with traumatic brain injury (TBI); however, its role in childhood TBI is controversial. We hypothesized that the transgenic expression of human APOE4 worsens the outcome after controlled cortical impact (CCI) in adult but not immature mice. Adult and immature APOE4 mice had worse motor outcome after CCI (P<0.001 versus wild type (WT)), but the Morris water maze performance was worse only in adult APOE4 mice (P=0.028 at 2 weeks, P=0.019 at 6 months versus WT), because immature APOE4 mice had performance similar to WT for up to 1 year after injury. Brain lesion size was similar in adult APOE4 mice but was decreased (P=0.029 versus WT) in injured immature APOE4 mice. Microgliosis was similar in all groups. Soluble brain Aβ40 was increased at 48 hours after CCI in adult and immature APOE4 mice and in adult WT (P<0.05), and was dynamically regulated during the chronic period by APOE4 in adults but not immature mice. The data suggest age-dependent effects of APOE4 on cognitive outcome after TBI, and that therapies targeting APOE4 may be more effective in adults versus children with TBI. PMID:20588316

  9. Manipulation of Ovarian Function Significantly Influenced Trabecular and Cortical Bone Volume, Architecture and Density in Mice at Death.

    Science.gov (United States)

    Mason, Jeffrey B; Terry, Boston C; Merchant, Samer S; Mason, Holly M; Nazokkarmaher, Mahdi

    2015-01-01

    Previously, transplantation of ovaries from young, cycling mice into old, postreproductive-age mice increased life span and decreased cardiomyopathy at death. We anticipated that the same factors that increased life span and decreased cardiomyopathy could also influence the progression of orthopedic disease. At 11 months of age, prepubertally ovariectomized and ovary-intact mice (including reproductively cycling and acyclic mice) received new 60-day-old ovaries. At death, epiphyseal bone in the proximal tibia and the distal femur and mid-shaft tibial and femoral diaphyseal bone was analyzed with micro-computed tomography. For qualitative analysis of osteophytosis, we also included mineralized connective tissue within the stifle joint. Prepubertal ovariectomy had the greatest influence on bone volume, ovarian transplantation had the greatest influence on bone architecture and both treatments influenced bone density. Ovarian transplantation increased cortical, but not trabecular bone density and tended to increase osteophytosis and heterotopic mineralization, except in acyclic recipients. These effects may have been dictated by the timing of the treatments, with ovariectomy appearing to influence early development and ovarian transplantation limited to influencing only the postreproductive period. However, major differences observed between cycling, acyclic and ovariectomized recipients of new ovaries may have been, in part due to differences in the levels of hormone receptors present and the responsiveness of specific bone processes to hormone signaling. Changes that resulted from these treatments may represent a compensatory response to normal age-associated, negative, orthopedic changes. Alternatively, differences between treatments may simply be the 'preservation' of unblemished orthopedic conditions, prior to the influence of negative, age-associated effects. These findings may suggest that in women, tailoring hormone replacement therapy to the patient's current

  10. Classification of cirrhotic patients with or without minimal hepatic encephalopathy and healthy subjects using resting-state attention-related network analysis.

    Directory of Open Access Journals (Sweden)

    Hua-Jun Chen

    Full Text Available BACKGROUND: Attention deficit is an early and key characteristic of minimal hepatic encephalopathy (MHE and has been used as indicator for MHE detection. The aim of this study is to classify the cirrhotic patients with or without MHE (NMHE and healthy controls (HC using the resting-state attention-related brain network analysis. METHODS AND FINDINGS: Resting-state fMRI was administrated to 20 MHE patients, 21 NMHE patients, and 17 HCs. Three attention-related networks, including dorsal attention network (DAN, ventral attention network (VAN, and default mode network (DMN, were obtained by independent component analysis. One-way analysis of covariance was performed to determine the regions of interest (ROIs showing significant functional connectivity (FC change. With FC strength of ROIs as indicators, Linear Discriminant Analysis (LDA was conducted to differentiate MHE from HC or NMHE. Across three groups, significant FC differences were found within DAN (left superior/inferior parietal lobule and right inferior parietal lobule, VAN (right superior parietal lobule, and DMN (bilateral posterior cingulate gyrus and precuneus, and left inferior parietal lobule. With FC strength of ROIs from three networks as indicators, LDA yielded 94.6% classification accuracy between MHE and HC (100% sensitivity and 88.2% specificity and 85.4% classification accuracy between MHE and NMHE (90.0% sensitivity and 81.0% specificity. CONCLUSIONS: Our results suggest that the resting-state attention-related brain network analysis can be useful in classification of subjects with MHE, NMHE, and HC and may provide a new insight into MHE detection.

  11. Communication and wiring in the cortical connectome

    Science.gov (United States)

    Budd, Julian M. L.; Kisvárday, Zoltán F.

    2012-01-01

    In cerebral cortex, the huge mass of axonal wiring that carries information between near and distant neurons is thought to provide the neural substrate for cognitive and perceptual function. The goal of mapping the connectivity of cortical axons at different spatial scales, the cortical connectome, is to trace the paths of information flow in cerebral cortex. To appreciate the relationship between the connectome and cortical function, we need to discover the nature and purpose of the wiring principles underlying cortical connectivity. A popular explanation has been that axonal length is strictly minimized both within and between cortical regions. In contrast, we have hypothesized the existence of a multi-scale principle of cortical wiring where to optimize communication there is a trade-off between spatial (construction) and temporal (routing) costs. Here, using recent evidence concerning cortical spatial networks we critically evaluate this hypothesis at neuron, local circuit, and pathway scales. We report three main conclusions. First, the axonal and dendritic arbor morphology of single neocortical neurons may be governed by a similar wiring principle, one that balances the conservation of cellular material and conduction delay. Second, the same principle may be observed for fiber tracts connecting cortical regions. Third, the absence of sufficient local circuit data currently prohibits any meaningful assessment of the hypothesis at this scale of cortical organization. To avoid neglecting neuron and microcircuit levels of cortical organization, the connectome framework should incorporate more morphological description. In addition, structural analyses of temporal cost for cortical circuits should take account of both axonal conduction and neuronal integration delays, which appear mostly of the same order of magnitude. We conclude the hypothesized trade-off between spatial and temporal costs may potentially offer a powerful explanation for cortical wiring patterns

  12. Distinct functional networks within the cerebellum and their relation to cortical systems assessed with independent component analysis

    NARCIS (Netherlands)

    Dobromyslin, V.I.; Salat, D.H.; Fortier, C.B.; Leritz, E.C.; Beckmann, Christian; Milberg, W.P.; McGlinchey, R.E.

    2012-01-01

    Cerebellar functional circuitry has been examined in several prior studies using resting fMRI data and seed-based procedures, as well as whole-brain independent component analysis (ICA). Here, we hypothesized that ICA applied to functional data from the cerebellum exclusively would provide increased

  13. Cortical vs. afferent stimulation as an adjunct to functional task practice training: a randomized, comparative pilot study in people with cervical spinal cord injury.

    Science.gov (United States)

    Gomes-Osman, Joyce; Field-Fote, Edelle C

    2015-08-01

    To assess single-session effects of three different types of stimuli known to increase cortical excitability when combined with functional task practice. Randomized cross-over trial. A total of 24 participants with chronic cervical spinal cord injury. One 30-minute session of each, applied concurrently with functional task practice: transcranial direct current stimulation, vibration, and transcutaneous electrical nerve stimulation. Nine-hole Peg Test, pinch force, visuomotor tracking, and cortical excitability were collected at pretest, posttest and late posttest (30 minutes after). Early effects (posttest minus pretest) and short-term persistence (late posttest minus pretest) were assessed using a general linear mixed model. Magnitude of effect size was assessed using the Cohen's d. Transcutaneous electrical nerve stimulation was associated with moderate, significant early effects and short-term persistence on Nine-hole Peg Test performance (1.8 ±1.8, p = 0.003, d = 0.59; 2.0 ±2.5, p stimulation (1.8 ±2.5, p = 0.003, Cohen's d = 0.52) was also associated with significant short-term persistence of moderate size on Nine-hole Peg Test performance (1.8 ±2.5, p = 0.003, Cohen's d = 0.52) and visuomotor tracking performance (p = 0.05, d = 0.51). Early effects on corticomotor excitability were significant for transcutaneous electrical nerve stimulation (p = 0.003), approached significance for transcranial direct current stimulation (p = 0.07), and only vibration was associated with significant short-term persistence (p = 0.006). Meaningful improvements in aspects of hand-related function that persisted at least 30 minutes after intervention were observed with transcutaneous electrical nerve stimulation and transcranial direct current stimulation, when combined with functional task practice. © The Author(s) 2014.

  14. Cross-species functional analyses reveal shared and separate roles for Sox11 in frog primary neurogenesis and mouse cortical neuronal differentiation

    Directory of Open Access Journals (Sweden)

    Chao Chen

    2016-04-01

    Full Text Available A well-functioning brain requires production of the correct number and types of cells during development; cascades of transcription factors are essential for cellular coordination. Sox proteins are transcription factors that affect various processes in the development of the nervous system. Sox11, a member of the SoxC family, is expressed in differentiated neurons and supports neuronal differentiation in several systems. To understand how generalizable the actions of Sox11 are across phylogeny, its function in the development of the frog nervous system and the mouse cerebral cortex were compared. Expression of Sox11 is largely conserved between these species; in the developing frog, Sox11 is expressed in the neural plate, neural tube and throughout the segmented brain, while in the mouse cerebral cortex, Sox11 is expressed in differentiated zones, including the preplate, subplate, marginal zone and cortical plate. In both frog and mouse, data demonstrate that Sox11 supports a role in promoting neuronal differentiation, with Sox11-positive cells expressing pan-neural markers and becoming morphologically complex. However, frog and mouse Sox11 cannot substitute for one another; a functional difference likely reflected in sequence divergence. Thus, Sox11 appears to act similarly in subserving neuronal differentiation but is species-specific in frog neural development and mouse corticogenesis.

  15. Alterations in the coupling functions between cortical and cardio-respiratory oscillations due to anaesthesia with propofol and sevoflurane

    Science.gov (United States)

    Stankovski, Tomislav; Petkoski, Spase; Raeder, Johan; Smith, Andrew F.; McClintock, Peter V. E.; Stefanovska, Aneta

    2016-05-01

    The precise mechanisms underlying general anaesthesia pose important and still open questions. To address them, we have studied anaesthesia induced by the widely used (intravenous) propofol and (inhalational) sevoflurane anaesthetics, computing cross-frequency coupling functions between neuronal, cardiac and respiratory oscillations in order to determine their mutual interactions. The phase domain coupling function reveals the form of the function defining the mechanism of an interaction, as well as its coupling strength. Using a method based on dynamical Bayesian inference, we have thus identified and analysed the coupling functions for six relationships. By quantitative assessment of the forms and strengths of the couplings, we have revealed how these relationships are altered by anaesthesia, also showing that some of them are differently affected by propofol and sevoflurane. These findings, together with the novel coupling function analysis, offer a new direction in the assessment of general anaesthesia and neurophysiological interactions, in general.

  16. Cortical Correlates of Fitts’ Law

    Directory of Open Access Journals (Sweden)

    Peter eIfft

    2011-12-01

    Full Text Available Fitts' law describes the fundamental trade-off between movement accuracy and speed: It states that the duration of reaching movements is a function of target size and distance. While Fitts' law has been extensively studied in ergonomics and has guided the design of human-computer interfaces, there have been few studies on its neuronal correlates. To elucidate sensorimotor cortical activity underlying Fitts’ law, we implanted two monkeys with multielectrode arrays in the primary motor (M1 and primary somatosensory (S1 cortices. The monkeys performed reaches with a joystick-controlled cursor towards targets of different size. The reaction time, movement time and movement velocity changed with target size, and M1 and S1 activity reflected these changes. Moreover, modifications of cortical activity could not be explained by changes of movement parameters alone, but required target size as an additional parameter. Neuronal representation of target size was especially prominent during the early reaction time period where it influenced the slope of the firing rate rise preceding movement initiation. During the movement period, cortical activity was mostly correlated with movement velocity. Neural decoders were applied to simultaneously decode target size and motor parameters from cortical modulations. We suggest using such classifiers to improve neuroprosthetic control.

  17. Modeling cortical circuits.

    Energy Technology Data Exchange (ETDEWEB)

    Rohrer, Brandon Robinson; Rothganger, Fredrick H.; Verzi, Stephen J.; Xavier, Patrick Gordon

    2010-09-01

    The neocortex is perhaps the highest region of the human brain, where audio and visual perception takes place along with many important cognitive functions. An important research goal is to describe the mechanisms implemented by the neocortex. There is an apparent regularity in the structure of the neocortex [Brodmann 1909, Mountcastle 1957] which may help simplify this task. The work reported here addresses the problem of how to describe the putative repeated units ('cortical circuits') in a manner that is easily understood and manipulated, with the long-term goal of developing a mathematical and algorithmic description of their function. The approach is to reduce each algorithm to an enhanced perceptron-like structure and describe its computation using difference equations. We organize this algorithmic processing into larger structures based on physiological observations, and implement key modeling concepts in software which runs on parallel computing hardware.

  18. Functional characterization of GABAA receptor-mediated modulation of cortical neuron network activity in microelectrode array recordings

    DEFF Research Database (Denmark)

    Bader, Benjamin M; Steder, Anne; Klein, Anders Bue

    2017-01-01

    The numerous γ-aminobutyric acid type A receptor (GABAAR) subtypes are differentially expressed and mediate distinct functions at neuronal level. In this study we have investigated GABAAR-mediated modulation of the spontaneous activity patterns of primary neuronal networks from murine frontal...

  19. The functional role of motor activation in language processing: Motor cortical oscillations support lexical-semantic retrieval

    NARCIS (Netherlands)

    Elk, M. van; Schie, H.T. van; Zwaan, R.A.; Bekkering, H.

    2010-01-01

    There is increasing experimental evidence that processing action-related language results in the automatic activation of associated regions of the motor and premotor cortex. However, the functional significance of motor activation in language processing is still under debate. In the present EEG

  20. The functional role of motor activation in language processing: Motor cortical oscillations support lexical-semantic retrieval

    NARCIS (Netherlands)

    M. van Elk (M.); H.T. van Schie (H.); R.A. Zwaan (Rolf); H. Bekkering (H.)

    2010-01-01

    textabstractThere is increasing experimental evidence that processing action-related language results in the automatic activation of associated regions of the motor and premotor cortex. However, the functional significance of motor activation in language processing is still under debate. In the

  1. Spatial attention related SEP amplitude modulations covary with BOLD signal in S1--a simultaneous EEG--fMRI study.

    Science.gov (United States)

    Schubert, Ruth; Ritter, Petra; Wüstenberg, Torsten; Preuschhof, Claudia; Curio, Gabriel; Sommer, Werner; Villringer, Arno

    2008-11-01

    Recent studies investigating the influence of spatial-selective attention on primary somatosensory processing have produced inconsistent results. The aim of this study was to explore the influence of tactile spatial-selective attention on spatiotemporal aspects of evoked neuronal activity in the primary somatosensory cortex (S1). We employed simultaneous electroencephalography (EEG)-functional magnetic resonance imaging (fMRI) in 14 right-handed subjects during bilateral index finger Braille stimulation to investigate the relationship between attentional effects on somatosensory evoked potential (SEP) components and the blood oxygenation level-dependent (BOLD) signal. The 1st reliable EEG response following left tactile stimulation (P50) was significantly enhanced by spatial-selective attention, which has not been reported before. FMRI analysis revealed increased activity in contralateral S1. Remarkably, the effect of attention on the P50 component as well as long-latency SEP components starting at 190 ms for left stimuli correlated with attentional effects on the BOLD signal in contralateral S1. The implications are 2-fold: First, the correlation between early and long-latency SEP components and the BOLD effect suggest that spatial-selective attention enhances processing in S1 at 2 time points: During an early passage of the signal and during a later passage, probably via re-entrant feedback from higher cortical areas. Second, attentional modulations of the fast electrophysiological signals and the slow hemodynamic response are linearly related in S1.

  2. Distinct functional networks within the cerebellum and their relation to cortical systems assessed with independent component analysis.

    Science.gov (United States)

    Dobromyslin, Vitaly I; Salat, David H; Fortier, Catherine B; Leritz, Elizabeth C; Beckmann, Christian F; Milberg, William P; McGlinchey, Regina E

    2012-05-01

    Cerebellar functional circuitry has been examined in several prior studies using resting fMRI data and seed-based procedures, as well as whole-brain independent component analysis (ICA). Here, we hypothesized that ICA applied to functional data from the cerebellum exclusively would provide increased sensitivity for detecting cerebellar networks compared to previous approaches. Consistency of group-level networks was assessed in two age- and sex-matched groups of twenty-five subjects each. Cerebellum-only ICA was compared to the traditional whole-brain ICA procedure to examine the potential gain in sensitivity of the novel method. In addition to replicating a number of previously identified cerebellar networks, the current approach revealed at least one network component that was not apparent with the application of whole brain ICA. These results demonstrate the gain in sensitivity attained through specifying the cerebellum as a target structure with regard to the identification of robust and reliable networks. The use of similar procedures could be important in further expanding on previously defined patterns of cerebellar functional anatomy, as well as provide information about unique networks that have not been explored in prior work. Such information may prove crucial for understanding the cognitive and behavioral importance of the cerebellum in health and disease. Published by Elsevier Inc.

  3. Functional near-infrared spectroscopy-based correlates of prefrontal cortical dynamics during a cognitive-motor executive adaptation task

    Directory of Open Access Journals (Sweden)

    Rodolphe J. Gentili

    2013-07-01

    Full Text Available This study investigated changes in brain hemodynamics, as measured by functional near infrared spectroscopy (fNIR, during performance of a cognitive-motor adaptation task. The adaptation task involved the learning of a novel visuo-motor transformation (a 60 degree counterclockwise screen-cursor rotation, which required inhibition of a pre-potent visuo-motor response. A control group experienced a familiar transformation and thus, did not face any executive challenge. Analysis of the experimental group hemodynamic responses revealed that the performance enhancement was associated with a monotonic reduction in the oxygenation level in the prefrontal cortex. This finding confirms and extends functional magnetic resonance imaging (fMRI and electroencephalography (EEG studies of visuo-motor adaptation and learning. The changes in prefrontal brain activation suggest an initial recruitment of frontal executive functioning to inhibit pre-potent visuo-motor mappings followed by a progressive de-recruitment of the same prefrontal regions. The prefrontal hemodynamic changes observed in the experimental group translated into enhanced motor performance revealed by a reduction in movement time, movement extent, root mean square error and the directional error. These kinematic adaptations are consistent with the acquisition of an internal model of the novel visuo-motor transformation. No comparable change was observed in the control group for either the hemodynamics or for the kinematics. This study 1 extends our understanding of the frontal executive processes from the cognitive to the cognitive-motor domain and 2 suggests that optical brain imaging can be employed to provide hemodynamic based-biomarkers to assess and monitor the level of adaptive cognitive-motor performance.

  4. Genetic targeting of NRXN2 in mice unveils role in excitatory cortical synapse function and social behaviors

    Directory of Open Access Journals (Sweden)

    Gesche eBorn

    2015-02-01

    Full Text Available Human genetics has identified rare copy number variations and deleterious mutations for all neurexin genes (NRXN1-3 in patients with neurodevelopmental diseases, and electrophysiological recordings in animal brains have shown that Nrxns are important for synaptic transmission. While several mouse models for Nrxn1α inactivation have previously been studied for behavioral changes, very little information is available for other variants. Here, we validate that mice lacking Nrxn2α exhibit behavioral abnormalities, characterized by social interaction deficits and increased anxiety-like behavior, which partially overlap, partially differ from Nrxn1α mutant behaviors. Using patch-clamp recordings in Nrxn2α knockout brains, we observe reduced spontaneous transmitter release at excitatory synapses in the neocortex. We also analyse at this cellular level a novel NRXN2 mouse model that carries a combined deletion of Nrxn2α and Nrxn2β. Electrophysiological analysis of this Nrxn2-mutant mouse shows surprisingly similar defects of excitatory release to Nrxn2α, indicating that the β-variant of Nrxn2 has no strong function in basic transmission at these synapses. Inhibitory transmission as well as synapse densities and ultrastructure remain unchanged in the neocortex of both models. Furthermore, at Nrxn2α and Nrxn2-mutant excitatory synapses we find an altered facilitation and N-methyl-D-aspartate receptor (NMDAR function because NMDAR-dependent decay time and NMDAR-mediated responses are reduced. As Nrxn can indirectly be linked to NMDAR via neuroligin and PSD-95, the trans-synaptic nature of this complex may help to explain occurrence of presynaptic and postsynaptic effects. Since excitatory/inhibitory imbalances and impairment of NMDAR function are alledged to have a role in autism and schizophrenia, our results support the idea of a related pathomechanism in these disorders.

  5. Prefrontal cortical-ventral striatal interactions involved in affective modulation of attentional performance: implications for corticostriatal circuit function.

    Science.gov (United States)

    Christakou, Anastasia; Robbins, Trevor W; Everitt, Barry J

    2004-01-28

    Anatomically segregated systems linking the frontal cortex and the striatum are involved in various aspects of cognitive, affective, and motor processing. In this study, we examined the effects of combined unilateral lesions of the medial prefrontal cortex (mPFC) and the core subregion of the nucleus accumbens (AcbC) in opposite hemispheres (disconnection) on a continuous performance, visual attention test [five-choice serial reaction-time task (5CSRTT)]. The disconnection lesion produced a set of specific changes in performance of the 5CSRTT, resembling changes that followed bilateral AcbC lesions while, in addition, comprising a subset of the behavioral changes after bilateral mPFC lesions previously reported using the same task. Specifically, both mPFC/AcbC disconnection and bilateral AcbC lesions markedly affected aspects of response control related to affective feedback, as indexed by perseverative responding in the 5CSRTT. These effects were comparable, although not identical, to those in animals with either bilateral AcbC or mPFC/AcbC disconnection lesions. The mPFC/AcbC disconnection resulted in a behavioral profile largely distinct from that produced by disconnection of a similar circuit described previously, between the mPFC and the dorsomedial striatum, which were shown to form a functional network underlying aspects of visual attention and attention to action. This distinction provides an insight into the functional specialization of corticostriatal circuits in similar behavioral contexts.

  6. Major depressive disorder and alterations in insular cortical activity: a review of current functional magnetic imaging (fMRI research.

    Directory of Open Access Journals (Sweden)

    Diane eSliz

    2012-12-01

    Full Text Available Major depressive disorder (MDD is characterized by a dysregulated fronto-limbic network. The hyperactivation of limbic regions leads to increased attention and processing of emotional information, with a bias toward negative stimuli. Pathological ruminative behavior is a common symptom of depressive disorder whereby the individual is unable to disengage from internal mental processing of emotionally-salient events. In fact, lower deactivations of the neural baseline resting state may account for the increased internal self-focus. The insular cortex, with its extensive connections to fronto-limbic and association areas has recently also been implicated to be a part of this network. Given its wide-reaching connectivity, it has been putatively implicated as an integration center of autonomic, visceromotor, emotional and interoceptive information. The following paper will review recent imaging findings of altered insular function and connectivity in depressive pathology.

  7. Superresolution improves MRI cortical segmentation with FACE

    DEFF Research Database (Denmark)

    Eskildsen, Simon Fristed; Manjón, José V.; Coupé, Pierrick

    Brain cortical surface extraction from MRI has applications for measurement of gray matter (GM) atrophy, functional mapping, source localization and preoperative neurosurgical planning. Accurate cortex segmentation requires high resolution morphological images and several methods for extracting...

  8. Acute aerobic exercise increases cortical activity during working memory: a functional MRI study in female college students.

    Science.gov (United States)

    Li, Lin; Men, Wei-Wei; Chang, Yu-Kai; Fan, Ming-Xia; Ji, Liu; Wei, Gao-Xia

    2014-01-01

    There is increasing evidence that acute aerobic exercise is associated with improved cognitive function. However, neural correlates of its cognitive plasticity remain largely unknown. The present study examined the effect of a session of acute aerobic exercise on working memory task-evoked brain activity as well as task performance. A within-subjects design with a counterbalanced order was employed. Fifteen young female participants (M = 19.56, SD = 0.81) were scanned using functional magnetic resonance imaging while performing a working memory task, the N-back task, both following an acute exercise session with 20 minutes of moderate intensity and a control rest session. Although an acute session of exercise did not improve behavioral performance, we observed that it had a significant impact on brain activity during the 2-back condition of the N-back task. Specifically, acute exercise induced increased brain activation in the right middle prefrontal gyrus, the right lingual gyrus, and the left fusiform gyrus as well as deactivations in the anterior cingulate cortexes, the left inferior frontal gyrus, and the right paracentral lobule. Despite the lack of an effect on behavioral measures, significant changes after acute exercise with activation of the prefrontal and occipital cortexes and deactivation of the anterior cingulate cortexes and left frontal hemisphere reflect the improvement of executive control processes, indicating that acute exercise could benefit working memory at a macro-neural level. In addition to its effects on reversing recent obesity and disease trends, our results provide substantial evidence highlighting the importance of promoting physical activity across the lifespan to prevent or reverse cognitive and neural decline.

  9. Cortical Odor Processing in Health and Disease

    Science.gov (United States)

    Wilson, Donald A.; Xu, Wenjin; Sadrian, Benjamin; Courtiol, Emmanuelle; Cohen, Yaniv; Barnes, Dylan C.

    2014-01-01

    The olfactory system has a rich cortical representation, including a large archicortical component present in most vertebrates, and in mammals neocortical components including the entorhinal and orbitofrontal cortices. Together, these cortical components contribute to normal odor perception and memory. They help transform the physicochemical features of volatile molecules inhaled or exhaled through the nose into the perception of odor objects with rich associative and hedonic aspects. This chapter focuses on how olfactory cortical areas contribute to odor perception and begins to explore why odor perception is so sensitive to disease and pathology. Odor perception is disrupted by a wide range of disorders including Alzheimer’s disease, Parkinson’s disease, schizophrenia, depression, autism, and early life exposure to toxins. This olfactory deficit often occurs despite maintained functioning in other sensory systems. Does the unusual network of olfactory cortical structures contribute to this sensitivity? PMID:24767487

  10. Effect of acute exercise and cardiovascular fitness on cognitive function: an event-related cortical desynchronization study.

    Science.gov (United States)

    Chang, Yu-Kai; Chu, Chien-Heng; Wang, Chun-Chih; Song, Tai-Fen; Wei, Gao-Xia

    2015-03-01

    This study aimed to clarify the effects of acute exercise and cardiovascular fitness on cognitive function using the Stroop test and event-related desynchronization (ERD) in an aged population. Old adults (63.10 ± 2.89 years) were first assigned to either a high-fitness or a low-fitness group, and they were then subjected to an acute exercise treatment and a reading control treatment in a counterbalanced order. Alpha ERD was recorded during the Stroop test, which was administered after both treatments. Acute exercise improved cognitive performance regardless of the level of cognition, and old adults with higher fitness levels received greater benefits from acute exercise. Additionally, acute exercise, rather than overall fitness, elicited greater lower and upper alpha ERDs relative to the control condition. These findings indirectly suggest that the beneficial effects of acute exercise on cognitive performance may result from exercise-induced attentional control observed during frontal neural excitation. © 2014 Society for Psychophysiological Research.

  11. Impaired Prefrontal Cortical Function and Disrupted Adaptive Cognitive Control in Methamphetamine Abusers: An fMRI Study

    Science.gov (United States)

    Salo, Ruth; Ursu, Stefan; Buonocore, Michael H.; Leamon, Martin H; Carter, Cameron

    2009-01-01

    Background Methamphetamine (MA) abuse is associated with neurotoxicity to frontostriatal brain regions with concomitant deleterious effects on cognitive processes. Deficits in behavioral control are thought to be one contributing factor to the sustainment of addictive behaviors in chronic MA abuse. Methods In order to examine patterns of behavioral control relevant to addiction, we employed a fast-event related fMRI design to examine trial to trial reaction time (RT) adjustments in 12 chronic MA abusers who met DSM-IV criteria for MA dependence and 16 non-substance abusing controls. A variant of the Stroop task was employed to contrast the groups on error rates, RT Stroop conflict effect and the level of trial-to-trial adjustments seen after incongruent trials. Results The MA abusers exhibited reduced RT adjustments along with reduced activation in the right prefrontal cortex compared to controls on conditions that measured the ability to use exposure to conflict situations (i.e., conflict trials) to regulate behavior. MA abusers did not differ from controls on accuracy rates or within-trial Stroop conflict effects. Conclusions The observed deficits in trial to trial RT adjustments suggest that the ability to adapt a behavioral response based on prior experience may be compromised in MA abusers. Such adjustments are critical to everyday functioning and deficits in modifying behavior based on prior events may reflect a key deficit that contributes to maladaptive drug seeking behavior. PMID:19136097

  12. Increased cortical activity in binge drinkers during working memory task: a preliminary assessment through a functional magnetic resonance imaging study.

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    Salvatore Campanella

    Full Text Available BACKGROUND: Cerebral dysfunction is a common feature of both chronic alcohol abusers and binge drinkers. Here, we aimed to study whether, at equated behavioral performance levels, binge drinkers exhibited increased neural activity while performing simple cognitive tasks. METHODS: Thirty-two participants (16 binge drinkers and 16 matched controls were scanned using functional magnetic resonance imaging (fMRI while performing an n-back working memory task. In the control zero-back (N0 condition, subjects were required to press a button with the right hand when the number "2" was displayed. In the two-back (N2 condition, subjects had to press a button when the displayed number was identical to the number shown two trials before. RESULTS: fMRI analyses revealed higher bilateral activity in the pre-supplementary motor area in binge drinkers than matched controls, even though behavioral performances were similar. Moreover, binge drinkers showed specific positive correlations between the number of alcohol doses consumed per occasion and higher activity in the dorsomedial prefrontal cortex, as well as between the number of drinking occasions per week and higher activity in cerebellum, thalamus and insula while performing the N2 memory task. CONCLUSIONS: Binge alcohol consumption leads to possible compensatory cerebral changes in binge drinkers that facilitate normal behavioral performance. These changes in cerebral responses may be considered as vulnerability factors for developing adult substance use disorders.

  13. Atrophy and Primary Somatosensory Cortical Reorganization after Unilateral Thoracic Spinal Cord Injury: A Longitudinal Functional Magnetic Resonance Imaging Study

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    Jia-Sheng Rao

    2013-01-01

    Full Text Available The effects of traumatic spinal cord injury (SCI on the changes in the central nervous system (CNS over time may depend on the dynamic interaction between the structural integrity of the spinal cord and the capacity of the brain plasticity. Functional magnetic resonance imaging (fMRI was used in a longitudinal study on five rhesus monkeys to observe cerebral activation during upper limb somatosensory tasks in healthy animals and after unilateral thoracic SCI. The changes in the spinal cord diameters were measured, and the correlations among time after the lesion, structural changes in the spinal cord, and primary somatosensory cortex (S1 reorganization were also determined. After SCI, activation of the upper limb in S1 shifted to the region which generally dominates the lower limb, and the rostral spinal cord transverse diameter adjacent to the lesion exhibited obvious atrophy, which reflects the SCI-induced changes in the CNS. A significant correlation was found among the time after the lesion, the spinal cord atrophy, and the degree of contralateral S1 reorganization. The results indicate the structural changes in the spinal cord and the dynamic reorganization of the cerebral activation following early SCI stage, which may help to further understand the neural plasticity in the CNS.

  14. Prefrontal cortical responses in children with prenatal alcohol-related neurodevelopmental impairment: A functional near-infrared spectroscopy study.

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    Kable, Julie A; Coles, Claire D

    2017-11-01

    Disruption in the neural activation of the prefrontal cortex (PFC) in modulating arousal was explored in children with heavy prenatal alcohol exposure (PAE), who have known neurobehavioral impairment. During a task that elicits frustration, functional near-infrared spectroscopy (fNIRS) was used to measure PFC activation, specifically levels of oxygenated (HBO) and deoxygenated (HBR) hemoglobin, in children with PAE (n=18) relative to typically developing Controls (n=12) and a Clinical Contrast group with other neurodevelopmental or behavioral problems (n=14). Children with PAE had less activation during conditions with positive emotional arousal, as indicated by lower levels of HBO in the medial areas of the PFC and higher levels of HBR in all areas of the PFC sampled relative to both other groups. Children in the Control group demonstrated greater differentiation of PFC activity than did children with PAE. Children in the Clinical Contrast group demonstrated the greatest differences in PFC activity between valences of task conditions. Specific patterns of PFC activation differentiated children with PAE from typically developing children and children with other clinical problems. FNIRS assessments of PFC activity provide new insights regarding the mechanisms of commonly seen neurobehavioral dysfunction in children with PAE. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

  15. Progressive posterior cortical dysfunction

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    Fábio Henrique de Gobbi Porto

    Full Text Available Abstract Progressive posterior cortical dysfunction (PPCD is an insidious syndrome characterized by prominent disorders of higher visual processing. It affects both dorsal (occipito-parietal and ventral (occipito-temporal pathways, disturbing visuospatial processing and visual recognition, respectively. We report a case of a 67-year-old woman presenting with progressive impairment of visual functions. Neurologic examination showed agraphia, alexia, hemispatial neglect (left side visual extinction, complete Balint's syndrome and visual agnosia. Magnetic resonance imaging showed circumscribed atrophy involving the bilateral parieto-occipital regions, slightly more predominant to the right . Our aim was to describe a case of this syndrome, to present a video showing the main abnormalities, and to discuss this unusual presentation of dementia. We believe this article can contribute by improving the recognition of PPCD.

  16. The Diversity of Cortical Inhibitory Synapses

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    Yoshiyuki eKubota

    2016-04-01

    Full Text Available The most typical and well known inhibitory action in the cortical microcircuit is a strong inhibition on the target neuron by axo-somatic synapses. However, it has become clear that synaptic inhibition in the cortex is much more diverse and complicated. Firstly, at least ten or more inhibitory non-pyramidal cell subtypes engage in diverse inhibitory functions to produce the elaborate activity characteristic of the different cortical states. Each distinct non-pyramidal cell subtype has its own independent inhibitory function. Secondly, the inhibitory synapses innervate different neuronal domains, such as axons, spines, dendrites and soma, and their IPSP size is not uniform. Thus cortical inhibition is highly complex, with a wide variety of anatomical and physiological modes. Moreover, the functional significance of the various inhibitory synapse innervation styles and their unique structural dynamic behaviors differ from those of excitatory synapses. In this review, we summarize our current understanding of the inhibitory mechanisms of the cortical microcircuit.

  17. Cortical Neural Computation by Discrete Results Hypothesis.

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    Castejon, Carlos; Nuñez, Angel

    2016-01-01

    One of the most challenging problems we face in neuroscience is to understand how the cortex performs computations. There is increasing evidence that the power of the cortical processing is produced by populations of neurons forming dynamic neuronal ensembles. Theoretical proposals and multineuronal experimental studies have revealed that ensembles of neurons can form emergent functional units. However, how these ensembles are implicated in cortical computations is still a mystery. Although cell ensembles have been associated with brain rhythms, the functional interaction remains largely unclear. It is still unknown how spatially distributed neuronal activity can be temporally integrated to contribute to cortical computations. A theoretical explanation integrating spatial and temporal aspects of cortical processing is still lacking. In this Hypothesis and Theory article, we propose a new functional theoretical framework to explain the computational roles of these ensembles in cortical processing. We suggest that complex neural computations underlying cortical processing could be temporally discrete and that sensory information would need to be quantized to be computed by the cerebral cortex. Accordingly, we propose that cortical processing is produced by the computation of discrete spatio-temporal functional units that we have called "Discrete Results" (Discrete Results Hypothesis). This hypothesis represents a novel functional mechanism by which information processing is computed in the cortex. Furthermore, we propose that precise dynamic sequences of "Discrete Results" is the mechanism used by the cortex to extract, code, memorize and transmit neural information. The novel "Discrete Results" concept has the ability to match the spatial and temporal aspects of cortical processing. We discuss the possible neural underpinnings of these functional computational units and describe the empirical evidence supporting our hypothesis. We propose that fast-spiking (FS

  18. Abnormal Left and Right Amygdala-Orbitofrontal Cortical Functional Connectivity to Emotional Faces: State Versus Trait Vulnerability Markers of Depression in Bipolar Disorder

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    Versace, Amelia; Thompson, Wesley K.; Zhou, Donli; Almeida, Jorge R.C.; Hassel, Stefanie; Klein, Crystal R.; Kupfer, David J.; Phillips, Mary L.

    2010-01-01

    Background Amygdala-orbitofrontal cortical (OFC) functional connectivity (FC) to emotional stimuli and relationships with white matter remain little examined in bipolar disorder individuals (BD). Methods Thirty-one BD (type I; n = 17 remitted; n = 14 depressed) and 24 age- and gender-ratio-matched healthy individuals (HC) viewed neutral, mild, and intense happy or sad emotional faces in two experiments. The FC was computed as linear and nonlinear dependence measures between amygdala and OFC time series. Effects of group, laterality, and emotion intensity upon amygdala-OFC FC and amygdala-OFC FC white matter fractional anisotropy (FA) relationships were examined. Results The BD versus HC showed significantly greater right amygdala-OFC FC (p ≤ .001) in the sad experiment and significantly reduced bilateral amygdala-OFC FC (p = .007) in the happy experiment. Depressed but not remitted female BD versus female HC showed significantly greater left amygdala-OFC FC (p = .001) to all faces in the sad experiment and reduced bilateral amygdala-OFC FC to intense happy faces (p = .01). There was a significant nonlinear relationship (p = .001) between left amygdala-OFC FC to sad faces and FA in HC. In BD, antidepressants were associated with significantly reduced left amygdala-OFC FC to mild sad faces (p = .001). Conclusions In BD, abnormally elevated right amygdala-OFC FC to sad stimuli might represent a trait vulnerability for depression, whereas abnormally elevated left amygdala-OFC FC to sad stimuli and abnormally reduced amygdala-OFC FC to intense happy stimuli might represent a depression state marker. Abnormal FC measures might normalize with antidepressant medications in BD. Nonlinear amygdala-OFC FC–FA relationships in BD and HC require further study. PMID:20159144

  19. Rab3A, a possible marker of cortical granules, participates in cortical granule exocytosis in mouse eggs.

    Science.gov (United States)

    Bello, Oscar Daniel; Cappa, Andrea Isabel; de Paola, Matilde; Zanetti, María Natalia; Fukuda, Mitsunori; Fissore, Rafael A; Mayorga, Luis S; Michaut, Marcela A

    2016-09-10

    Fusion of cortical granules with the oocyte plasma membrane is the most significant event to prevent polyspermy. This particular exocytosis, also known as cortical reaction, is regulated by calcium and its molecular mechanism is still not known. Rab3A, a member of the small GTP-binding protein superfamily, has been implicated in calcium-dependent exocytosis and is not yet clear whether Rab3A participates in cortical granules exocytosis. Here, we examine the involvement of Rab3A in the physiology of cortical granules, particularly, in their distribution during oocyte maturation and activation, and their participation in membrane fusion during cortical granule exocytosis. Immunofluorescence and Western blot analysis showed that Rab3A and cortical granules have a similar migration pattern during oocyte maturation, and that Rab3A is no longer detected after cortical granule exocytosis. These results suggested that Rab3A might be a marker of cortical granules. Overexpression of EGFP-Rab3A colocalized with cortical granules with a Pearson correlation coefficient of +0.967, indicating that Rab3A and cortical granules have almost a perfect colocalization in the egg cortical region. Using a functional assay, we demonstrated that microinjection of recombinant, prenylated and active GST-Rab3A triggered cortical granule exocytosis, indicating that Rab3A has an active role in this secretory pathway. To confirm this active role, we inhibited the function of endogenous Rab3A by microinjecting a polyclonal antibody raised against Rab3A prior to parthenogenetic activation. Our results showed that Rab3A antibody microinjection abolished cortical granule exocytosis in parthenogenetically activated oocytes. Altogether, our findings confirm that Rab3A might function as a marker of cortical granules and participates in cortical granule exocytosis in mouse eggs. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Mnemonic Encoding and Cortical Organization in Parietal and Prefrontal Cortices.

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    Masse, Nicolas Y; Hodnefield, Jonathan M; Freedman, David J

    2017-06-21

    Persistent activity within the frontoparietal network is consistently observed during tasks that require working memory. However, the neural circuit mechanisms underlying persistent neuronal encoding within this network remain unresolved. Here, we ask how neural circuits support persistent activity by examining population recordings from posterior parietal (PPC) and prefrontal (PFC) cortices in two male monkeys that performed spatial and motion direction-based tasks that required working memory. While spatially selective persistent activity was observed in both areas, robust selective persistent activity for motion direction was only observed in PFC. Crucially, we find that this difference between mnemonic encoding in PPC and PFC is associated with the presence of functional clustering: PPC and PFC neurons up to ∼700 μm apart preferred similar spatial locations, and PFC neurons up to ∼700 μm apart preferred similar motion directions. In contrast, motion-direction tuning similarity between nearby PPC neurons was much weaker and decayed rapidly beyond ∼200 μm. We also observed a similar association between persistent activity and functional clustering in trained recurrent neural network models embedded with a columnar topology. These results suggest that functional clustering facilitates mnemonic encoding of sensory information. SIGNIFICANCE STATEMENT Working memory refers to our ability to temporarily store and manipulate information. Numerous studies have observed that, during working memory, neurons in higher cortical areas, such as the parietal and prefrontal cortices, mnemonically encode the remembered stimulus. However, several recent studies have failed to observe mnemonic encoding during working memory, raising the question as to why mnemonic encoding is observed during some, but not all, conditions. In this study, we show that mnemonic encoding occurs when a cortical area is organized such that nearby neurons preferentially respond to the same

  1. Improved diagnostic accuracy of Alzheimer's disease by combining regional cortical thickness and default mode network functional connectivity: Validated in the Alzheimer's disease neuroimaging initiative set

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    Park, Ji Eun; Park, Bum Woo; Kim, Sang Joon; Kim, Ho Sung; Choi, Choong Gon; Jung, Seung Jung; Oh, Joo Young; Shim, Woo Hyun [Dept. of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul (Korea, Republic of); Lee, Jae Hong; Roh, Jee Hoon [University of Ulsan College of Medicine, Asan Medical Center, Seoul (Korea, Republic of)

    2017-11-15

    To identify potential imaging biomarkers of Alzheimer's disease by combining brain cortical thickness (CThk) and functional connectivity and to validate this model's diagnostic accuracy in a validation set. Data from 98 subjects was retrospectively reviewed, including a study set (n = 63) and a validation set from the Alzheimer's Disease Neuroimaging Initiative (n = 35). From each subject, data for CThk and functional connectivity of the default mode network was extracted from structural T1-weighted and resting-state functional magnetic resonance imaging. Cortical regions with significant differences between patients and healthy controls in the correlation of CThk and functional connectivity were identified in the study set. The diagnostic accuracy of functional connectivity measures combined with CThk in the identified regions was evaluated against that in the medial temporal lobes using the validation set and application of a support vector machine. Group-wise differences in the correlation of CThk and default mode network functional connectivity were identified in the superior temporal (p < 0.001) and supramarginal gyrus (p = 0.007) of the left cerebral hemisphere. Default mode network functional connectivity combined with the CThk of those two regions were more accurate than that combined with the CThk of both medial temporal lobes (91.7% vs. 75%). Combining functional information with CThk of the superior temporal and supramarginal gyri in the left cerebral hemisphere improves diagnostic accuracy, making it a potential imaging biomarker for Alzheimer's disease.

  2. Exercise training reinstates cortico-cortical sensorimotor functional connectivity following striatal lesioning: Development and application of a subregional-level analytic toolbox for perfusion autoradiographs of the rat brain

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    Peng, Yu-Hao; Heintz, Ryan; Wang, Zhuo; Guo, Yumei; Myers, Kalisa; Scremin, Oscar; Maarek, Jean-Michel; Holschneider, Daniel

    2014-12-01

    Current rodent connectome projects are revealing brain structural connectivity with unprecedented resolution and completeness. How subregional structural connectivity relates to subregional functional interactions is an emerging research topic. We describe a method for standardized, mesoscopic-level data sampling from autoradiographic coronal sections of the rat brain, and for correlation-based analysis and intuitive display of cortico-cortical functional connectivity (FC) on a flattened cortical map. A graphic user interface “Cx-2D” allows for the display of significant correlations of individual regions-of-interest, as well as graph theoretical metrics across the cortex. Cx-2D was tested on an autoradiographic data set of cerebral blood flow (CBF) of rats that had undergone bilateral striatal lesions, followed by 4 weeks of aerobic exercise training or no exercise. Effects of lesioning and exercise on cortico-cortical FC were examined during a locomotor challenge in this rat model of Parkinsonism. Subregional FC analysis revealed a rich functional reorganization of the brain in response to lesioning and exercise that was not apparent in a standard analysis focused on CBF of isolated brain regions. Lesioned rats showed diminished degree centrality of lateral primary motor cortex, as well as neighboring somatosensory cortex--changes that were substantially reversed in lesioned rats following exercise training. Seed analysis revealed that exercise increased positive correlations in motor and somatosensory cortex, with little effect in non-sensorimotor regions such as visual, auditory, and piriform cortex. The current analysis revealed that exercise partially reinstated sensorimotor FC lost following dopaminergic deafferentation. Cx-2D allows for standardized data sampling from images of brain slices, as well as analysis and display of cortico-cortical FC in the rat cerebral cortex with potential applications in a variety of autoradiographic and histologic

  3. Exercise training reinstates cortico-cortical sensorimotor functional connectivity following striatal lesioning: Development and application of a subregional-level analytic toolbox for perfusion autoradiographs of the rat brain

    Directory of Open Access Journals (Sweden)

    Yu-Hao ePeng

    2014-12-01

    Full Text Available Current rodent connectome projects are revealing brain structural connectivity with unprecedented resolution and completeness. How subregional structural connectivity relates to subregional functional interactions is an emerging research topic. We describe a method for standardized, mesoscopic-level data sampling from autoradiographic coronal sections of the rat brain, and for correlation-based analysis and intuitive display of cortico-cortical functional connectivity (FC on a flattened cortical map. A graphic user interface Cx-2D allows for the display of significant correlations of individual regions-of-interest, as well as graph theoretical metrics across the cortex. Cx-2D was tested on an autoradiographic data set of cerebral blood flow (CBF of rats that had undergone bilateral striatal lesions, followed by 4 weeks of aerobic exercise training or no exercise. Effects of lesioning and exercise on cortico-cortical FC were examined during a locomotor challenge in this rat model of Parkinsonism. Subregional FC analysis revealed a rich functional reorganization of the brain in response to lesioning and exercise that was not apparent in a standard analysis focused on CBF of isolated brain regions. Lesioned rats showed diminished degree centrality of lateral primary motor cortex, as well as neighboring somatosensory cortex–-changes that were substantially reversed in lesioned rats following exercise training. Seed analysis revealed that exercise increased positive correlations in motor and somatosensory cortex, with little effect in non-sensorimotor regions such as visual, auditory, and piriform cortex. The current analysis revealed that exercise partially reinstated sensorimotor FC lost following dopaminergic deafferentation. Cx-2D allows for standardized data sampling from images of brain slices, as well as analysis and display of cortico-cortical FC in the rat cerebral cortex with potential applications in a variety of autoradiographic and

  4. Rab3A, a possible marker of cortical granules, participates in cortical granule exocytosis in mouse eggs

    Energy Technology Data Exchange (ETDEWEB)

    Bello, Oscar Daniel; Cappa, Andrea Isabel; Paola, Matilde de; Zanetti, María Natalia [Instituto de Histología y Embriología, CONICET – Universidad Nacional de Cuyo, Av. Libertador 80, 5500 Mendoza (Argentina); Fukuda, Mitsunori [Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578 (Japan); Fissore, Rafael A. [Department of Veterinary and Animal Sciences, University of Massachusetts Amherst, 661 North Pleasant Street, Amherst, MA 01003 (United States); Mayorga, Luis S. [Instituto de Histología y Embriología, CONICET – Universidad Nacional de Cuyo, Av. Libertador 80, 5500 Mendoza (Argentina); Michaut, Marcela A., E-mail: mmichaut@gmail.com [Instituto de Histología y Embriología, CONICET – Universidad Nacional de Cuyo, Av. Libertador 80, 5500 Mendoza (Argentina); Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo (Argentina)

    2016-09-10

    Fusion of cortical granules with the oocyte plasma membrane is the most significant event to prevent polyspermy. This particular exocytosis, also known as cortical reaction, is regulated by calcium and its molecular mechanism is still not known. Rab3A, a member of the small GTP-binding protein superfamily, has been implicated in calcium-dependent exocytosis and is not yet clear whether Rab3A participates in cortical granules exocytosis. Here, we examine the involvement of Rab3A in the physiology of cortical granules, particularly, in their distribution during oocyte maturation and activation, and their participation in membrane fusion during cortical granule exocytosis. Immunofluorescence and Western blot analysis showed that Rab3A and cortical granules have a similar migration pattern during oocyte maturation, and that Rab3A is no longer detected after cortical granule exocytosis. These results suggested that Rab3A might be a marker of cortical granules. Overexpression of EGFP-Rab3A colocalized with cortical granules with a Pearson correlation coefficient of +0.967, indicating that Rab3A and cortical granules have almost a perfect colocalization in the egg cortical region. Using a functional assay, we demonstrated that microinjection of recombinant, prenylated and active GST-Rab3A triggered cortical granule exocytosis, indicating that Rab3A has an active role in this secretory pathway. To confirm this active role, we inhibited the function of endogenous Rab3A by microinjecting a polyclonal antibody raised against Rab3A prior to parthenogenetic activation. Our results showed that Rab3A antibody microinjection abolished cortical granule exocytosis in parthenogenetically activated oocytes. Altogether, our findings confirm that Rab3A might function as a marker of cortical granules and participates in cortical granule exocytosis in mouse eggs. - Highlights: • Rab3A has a similar migration pattern to cortical granules in mouse oocytes. • Rab3A can be a marker of

  5. Genetic Animal Models of Malformations of Cortical Development and Epilepsy

    Science.gov (United States)

    Wong, Michael; Roper, Steven N.

    2015-01-01

    Malformations of cortical development constitute a variety of pathological brain abnormalities that commonly cause severe, medically-refractory epilepsy, including focal lesions, such as focal cortical dysplasia, hetereotopias, and tubers of tuberous sclerosis complex, and diffuse malformations, such as lissencephaly. Although some cortical malformations result from environmental insults during cortical development in utero, genetic factors are increasingly recognized as primary pathogenic factors across the entire spectrum of malformations. Genes implicated in causing different cortical malformations are involved in a variety of physiological functions, but many are focused on regulation of cell proliferation, differentiation, and neuronal migration. Advances in molecular genetic methods have allowed the engineering of increasingly sophisticated animal models of cortical malformations and associated epilepsy. These animal models have identified some common mechanistic themes shared by a number of different cortical malformations, but also revealed the diversity and complexity of cellular and molecular mechanisms that lead to the development of the pathological lesions and resulting epileptogenesis. PMID:25911067

  6. Cortical Lewy Body Dementia

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    W. R. G. Gibb

    1990-01-01

    Full Text Available In cortical Lewy body dementia the distribution of Lewy bodies in the nervous system follows that of Parkinson's disease, except for their greater profusion in the cerebral cortex. The cortical tangles and plaques of Alzheimer pathology are often present, the likely explanation being that Alzheimer pathology provokes dementia in many patients. Pure cortical Lewy body dementia without Alzheimer pathology is uncommon. The age of onset reflects that of Parkinson's disease, and clinical features, though not diagnostic, include aphasias, apraxias, agnosias, paranoid delusions and visual hallucinations. Parkinsonism may present before or after the dementia, and survival duration is approximately half that seen in Parkinson's disease without dementia.

  7. Incomplete cortical reorganization in macular degeneration.

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    Liu, Tingting; Cheung, Sing-Hang; Schuchard, Ronald A; Glielmi, Christopher B; Hu, Xiaoping; He, Sheng; Legge, Gordon E

    2010-12-01

    Activity in regions of the visual cortex corresponding to central scotomas in subjects with macular degeneration (MD) is considered evidence for functional reorganization in the brain. Three unresolved issues related to cortical activity in subjects with MD were addressed: Is the cortical response to stimuli presented to the preferred retinal locus (PRL) different from other retinal loci at the same eccentricity? What effect does the role of age of onset and etiology of MD have on cortical responses? How do functional responses in an MD subject's visual cortex vary for task and stimulus conditions? Eight MD subjects-four with age-related onset (AMD) and four with juvenile onset (JMD)-and two age-matched normal vision controls, participated in three testing conditions while undergoing functional magnetic resonance imaging (fMRI). First, subjects viewed a small stimulus presented at the PRL compared with a non-PRL control location to investigate the role of the PRL. Second, they viewed a full-field flickering checkerboard compared with a small stimulus in the original fovea to investigate brain activation with passive viewing. Third, they performed a one-back task with scene images to investigate brain activation with active viewing. A small stimulus at the PRL generated more extensive cortical activation than at a non-PRL location, but neither yielded activation in the foveal cortical projection. Both passive and active viewing of full-field stimuli left a silent zone at the posterior pole of the occipital cortex, implying a lack of complete cortical reorganization. The silent zone was smaller in the task requiring active viewing compared with the task requiring passive viewing, especially in JMD subjects. The PRL for MD subjects has more extensive cortical representation than a retinal region with matched eccentricity. There is evidence for incomplete functional reorganization of early visual cortex in both JMD and AMD. Functional reorganization is more prominent

  8. Cortical Activation during Action Observation, Action Execution, and Interpersonal Synchrony in Adults: A functional Near-Infrared Spectroscopy (fNIRS Study

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    Anjana N. Bhat

    2017-09-01

    Full Text Available Introduction: Humans engage in Interpersonal Synchrony (IPS as they synchronize their own actions with that of a social partner over time. When humans engage in imitation/IPS behaviors, multiple regions in the frontal, temporal, and parietal cortices are activated including the putative Mirror Neuron Systems (Iacoboni, 2005; Buxbaum et al., 2014. In the present study, we compared fNIRS-based cortical activation patterns across three conditions of action observation (“Watch” partner, action execution (“Do” on your own, and IPS (move “Together”.Methods: Fifteen typically developing adults completed a reach and cleanup task with the right arm while cortical activation was examined using a 24-channel, Hitachi fNIRS system. Each adult completed 8 trials across three conditions (Watch, Do, and Together. For each fNIRS channel, we obtained oxy hemoglobin (HbO2 and deoxy hemoglobin (HHb profiles. Spatial registration methods were applied to localize the cortical regions underneath each channel and to define six regions of interest (ROIs, right and left supero-anterior (SA or pre/post-central gyri, infero-posterior (IP or angular/supramarginal gyri, and infero-anterior (IA or superior/middle temporal gyri regions.Results: In terms of task-related differences, the majority of the ROIs were more active during Do and Together compared to Watch. Only the right/ipsilateral fronto-parietal and inferior parietal cortices had greater activation during Together compared to Do.Conclusions: The similarities in cortical activation between action execution and IPS suggest that neural control of IPS is more similar to its execution than observational aspects. To be clear, the more complex the actions performed, the more difficult the IPS behaviors. Secondly, IPS behaviors required slightly more right-sided activation (vs. execution/observation suggesting that IPS is a higher-order process involving more bilateral activation compared to its sub

  9. Cortical Activation during Action Observation, Action Execution, and Interpersonal Synchrony in Adults: A functional Near-Infrared Spectroscopy (fNIRS) Study.

    Science.gov (United States)

    Bhat, Anjana N; Hoffman, Michael D; Trost, Susanna L; Culotta, McKenzie L; Eilbott, Jeffrey; Tsuzuki, Daisuke; Pelphrey, Kevin A

    2017-01-01

    Introduction: Humans engage in Interpersonal Synchrony (IPS) as they synchronize their own actions with that of a social partner over time. When humans engage in imitation/IPS behaviors, multiple regions in the frontal, temporal, and parietal cortices are activated including the putative Mirror Neuron Systems (Iacoboni, 2005; Buxbaum et al., 2014). In the present study, we compared fNIRS-based cortical activation patterns across three conditions of action observation ("Watch" partner), action execution ("Do" on your own), and IPS (move "Together"). Methods: Fifteen typically developing adults completed a reach and cleanup task with the right arm while cortical activation was examined using a 24-channel, Hitachi fNIRS system. Each adult completed 8 trials across three conditions (Watch, Do, and Together). For each fNIRS channel, we obtained oxy hemoglobin (HbO2) and deoxy hemoglobin (HHb) profiles. Spatial registration methods were applied to localize the cortical regions underneath each channel and to define six regions of interest (ROIs), right and left supero-anterior (SA or pre/post-central gyri), infero-posterior (IP or angular/supramarginal gyri), and infero-anterior (IA or superior/middle temporal gyri) regions. Results: In terms of task-related differences, the majority of the ROIs were more active during Do and Together compared to Watch. Only the right/ipsilateral fronto-parietal and inferior parietal cortices had greater activation during Together compared to Do. Conclusions: The similarities in cortical activation between action execution and IPS suggest that neural control of IPS is more similar to its execution than observational aspects. To be clear, the more complex the actions performed, the more difficult the IPS behaviors. Secondly, IPS behaviors required slightly more right-sided activation (vs. execution/observation) suggesting that IPS is a higher-order process involving more bilateral activation compared to its sub-components. These findings

  10. Cortical Activation during Action Observation, Action Execution, and Interpersonal Synchrony in Adults: A functional Near-Infrared Spectroscopy (fNIRS) Study

    Science.gov (United States)

    Bhat, Anjana N.; Hoffman, Michael D.; Trost, Susanna L.; Culotta, McKenzie L.; Eilbott, Jeffrey; Tsuzuki, Daisuke; Pelphrey, Kevin A.

    2017-01-01

    Introduction: Humans engage in Interpersonal Synchrony (IPS) as they synchronize their own actions with that of a social partner over time. When humans engage in imitation/IPS behaviors, multiple regions in the frontal, temporal, and parietal cortices are activated including the putative Mirror Neuron Systems (Iacoboni, 2005; Buxbaum et al., 2014). In the present study, we compared fNIRS-based cortical activation patterns across three conditions of action observation (“Watch” partner), action execution (“Do” on your own), and IPS (move “Together”). Methods: Fifteen typically developing adults completed a reach and cleanup task with the right arm while cortical activation was examined using a 24-channel, Hitachi fNIRS system. Each adult completed 8 trials across three conditions (Watch, Do, and Together). For each fNIRS channel, we obtained oxy hemoglobin (HbO2) and deoxy hemoglobin (HHb) profiles. Spatial registration methods were applied to localize the cortical regions underneath each channel and to define six regions of interest (ROIs), right and left supero-anterior (SA or pre/post-central gyri), infero-posterior (IP or angular/supramarginal gyri), and infero-anterior (IA or superior/middle temporal gyri) regions. Results: In terms of task-related differences, the majority of the ROIs were more active during Do and Together compared to Watch. Only the right/ipsilateral fronto-parietal and inferior parietal cortices had greater activation during Together compared to Do. Conclusions: The similarities in cortical activation between action execution and IPS suggest that neural control of IPS is more similar to its execution than observational aspects. To be clear, the more complex the actions performed, the more difficult the IPS behaviors. Secondly, IPS behaviors required slightly more right-sided activation (vs. execution/observation) suggesting that IPS is a higher-order process involving more bilateral activation compared to its sub

  11. Cortical Network for Reading Linear Words in an Alphasyllabary

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    Das, Tanusree; Bapi, Raju S.; Padakannaya, Prakash; Singh, Nandini C.

    2011-01-01

    Functional imaging studies have established cortical networks for reading alphabetic, syllabic and logographic scripts. There is little information about the different cortical areas that participate in reading an alphasyllabary. We use functional brain imaging to study the reading network for Devanagari, an alphasyllabary. Similar to syllabic…

  12. Changes in Motor-related Cortical Activity Following Deep Brain Stimulation for Parkinson's Disease Detected by Functional Near Infrared Spectroscopy: A Pilot Study

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    Takashi Morishita

    2016-12-01

    Full Text Available It remains unclear how deep brain stimulation (DBS modulates the global neuronal network involving cortical activity. We aimed to evaluate changes in cortical activity in six (two men; four women patients with Parkinson's disease (PD who underwent unilateral globus pallidus interna DBS surgery using a multi-channel near infrared spectroscopy (NIRS system. As five of the patients were right-handed, DBS was performed on the left in these five cases. The mean age was 66.8 ± 4.0 years. The unified Parkinson's disease rating scale (UPDRS motor scores were evaluated at baseline and 1- and 6-month follow-up. Task-related NIRS experiments applying the block design were performed at baseline and one-month follow-up. The mean of the total UPDRS motor score was 48.5 ± 11.1 in the off-medication state preoperatively. Postoperatively, total UPDRS motor scores improved to 26.8 ± 16.6 (p < 0.05 and 22.2 ± 8.6 (p < 0.05 at 1- and 6-month follow-up, respectively. A task-related NIRS experiment showed a postoperative increase in the cortical activity of the prefrontal cortex comparable to the preoperative state. To our knowledge, this is the first study to use a multi-channel NIRS system for PD patients treated with DBS. In this pilot study, we showed changes in motor-associated cortical activities following DBS surgery. Therapeutic DBS was concluded to have promoted the underlying neuronal network remodeling.

  13. Functional signature of recovering cortex: dissociation of local field potentials and spiking activity in somatosensory cortices of spinal cord injured monkeys.

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    Wang, Zheng; Qi, Hui-Xin; Kaas, Jon H; Roe, Anna W; Chen, Li Min

    2013-11-01

    After disruption of dorsal column afferents at high cervical spinal levels in adult monkeys, somatosensory cortical neurons recover responsiveness to tactile stimulation of the hand; this reactivation correlates with a recovery of hand use. However, it is not known if all neuronal response properties recover, and whether different cortical areas recover in a similar manner. To address this, we recorded neuronal activity in cortical area 3b and S2 in adult squirrel monkeys weeks after unilateral lesion of the dorsal columns. We found that in response to vibrotactile stimulation, local field potentials remained robust at all frequency ranges. However, neuronal spiking activity failed to follow at high frequencies (≥15 Hz). We suggest that the failure to generate spiking activity at high stimulus frequency reflects a changed balance of inhibition and excitation in both area 3b and S2, and that this mismatch in spiking and local field potential is a signature of an early phase of recovering cortex (

  14. Differential distribution and function of GABABRs in somato-dendritic and axonal compartments of principal cells and interneurons in cortical circuits.

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    Kulik, Ákos; Booker, Sam A; Vida, Imre

    2017-10-14

    GABABRs are highly expressed in cortical circuits, controlling neuronal excitability and synaptic transmission in both principal cells and inhibitory interneurons. Light and electron microscopic studies confirmed the wide distribution of receptors and revealed cell type-specific quantitative differences in their cellular and subcellular distributions. At the subcellular level, GABABRs are abundant at the peri- and extrasynaptic membrane of somato-dendritic compartments and to lower levels in the axon terminals of both cortical excitatory principal cells and inhibitory interneurons. Differences in the surface densities are particularly prominent between neurochemically-defined interneuron types. Whole-cell recordings further demonstrated that GABABRs differentially mediate post- and presynaptic inhibition in principal cells and various GABAergic interneurons by preferentially modulating postsynaptic G-protein-coupled inwardly rectifying K+ (Kir3) channels and presynaptic high voltage-activated Ca2+ (Cav) channels. These data convergently indicate that GABABRs not only control the overall level of neuronal excitability and activity, but can also fine tune the activation and interactions of excitatory and inhibitory neurons in cortical circuits. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Neurodynamics of somatosensory cortices studied by magnetoencephelography.

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    Kishida, Kuniharu

    2013-09-01

    From the viewpoint of statistical inverse problems, identification of transfer functions in feedback models is applied for neurodynamics of somatosensory cortices, and brain communication among active regions can be expressed in terms of transfer functions. However, brain activities have been investigated mainly by averaged waveforms in the conventional magnetoencephalography analysis, and thus brain communication among active regions has not yet been identified. It is shown that brain communication among two more than three brain regions is determined, when fluctuations related to concatenate averaged waveforms can be obtained by using a suitable blind source separation method. In blind identification of feedback model, some transfer functions or their impulse responses between output variables of current dipoles corresponding to active regions are identified from reconstructed time series data of fluctuations by the method of inverse problem. Neurodynamics of somatosensory cortices in 5 Hz median nerve stimuli can be shown by cerebral communication among active regions of somatosensory cortices in terms of impulse responses of feedback model.

  16. [Posterior cortical atrophy. Report of five cases].

    Science.gov (United States)

    Delgado D, Carolina; Donoso S, Archibaldo

    2009-11-01

    Posterior cortical atrophy (PCA) is a neurodegenerative syndrome, usually due to Alzheimer's disease. The first symptoms are progressive impairment of visuo spatial (Balint's and Gertsmann's syndromes) or visuo perceptive (visual agnosia, alexia) function. Episodic memory and executive function are spared until later stages. We report two males aged 51 and 55years and three females aged 50, 54 and 56 years, with posterior cortical atrophy. Ophthalmologic study was normal in all. Presenting signs and symptoms were visual ataxia, simultagnosia, agraphia, acalculia, spatial disorientation and unilateral neglect (Balint's and Gerstmann's syndromes). Apperceptive visual agnosia, aphasia, apraxia and alexia were also observed. One female had cortical blindness. Structural images were inconclusive, but PET scan and SPECT disclosed functional impairments in occipitotemporal or occipitoparietal areas.

  17. Functional mapping of thalamic nuclei and their integration into cortico-striatal-thalamo-cortical loops via ultra-high resolution imaging- From animal anatomy to in vivo imaging in humans

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    Coraline D. Metzger

    2013-05-01

    Full Text Available The thalamus, a crucial node in the well-described cortico-striatal-thalamo-cortical circuits, has been the focus of functional and structural imaging studies investigating human emotion, cognition and memory. Invasive work in animals and post-mortem investigations have revealed the rich cytoarchitectonics and functional specificity of the thalamus. Given current restrictions in the spatial resolution of non-invasive imaging modalities, there is, however, a translational gap between functional and structural information on these circuits in humans and animals as well as between histological and cellular evidence and their relationship to psychological functioning.With the advance of higher field strengths for MR approaches, better spatial resolution is now available promising to overcome this conceptual problem.We here review these two levels, which exist for both neuroscientific and clinical investigations, and then focus on current attempts to overcome conceptual boundaries of these observations with the help of high-resolution imaging.

  18. Decreased prefrontal cortical dopamine transmission in alcoholism.

    Science.gov (United States)

    Narendran, Rajesh; Mason, Neale Scott; Paris, Jennifer; Himes, Michael L; Douaihy, Antoine B; Frankle, W Gordon

    2014-08-01

    Basic studies have demonstrated that optimal levels of prefrontal cortical dopamine are critical to various executive functions such as working memory, attention, inhibitory control, and risk/reward decisions, all of which are impaired in addictive disorders such as alcoholism. Based on this and imaging studies of alcoholism that have demonstrated less dopamine in the striatum, the authors hypothesized decreased dopamine transmission in the prefrontal cortex in persons with alcohol dependence. To test this hypothesis, amphetamine and [11C]FLB 457 positron emission tomography were used to measure cortical dopamine transmission in 21 recently abstinent persons with alcohol dependence and 21 matched healthy comparison subjects. [11C]FLB 457 binding potential, specific compared to nondisplaceable uptake (BPND), was measured in subjects with kinetic analysis using the arterial input function both before and after 0.5 mg kg-1 of d-amphetamine. Amphetamine-induced displacement of [11C]FLB 457 binding potential (ΔBPND) was significantly smaller in the cortical regions in the alcohol-dependent group compared with the healthy comparison group. Cortical regions that demonstrated lower dopamine transmission in the alcohol-dependent group included the dorsolateral prefrontal cortex, medial prefrontal cortex, orbital frontal cortex, temporal cortex, and medial temporal lobe. The results of this study, for the first time, unambiguously demonstrate decreased dopamine transmission in the cortex in alcoholism. Further research is necessary to understand the clinical relevance of decreased cortical dopamine as to whether it is related to impaired executive function, relapse, and outcome in alcoholism.

  19. Cortical maturation and myelination in healthy toddlers and young children.

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    Deoni, Sean C L; Dean, Douglas C; Remer, Justin; Dirks, Holly; O'Muircheartaigh, Jonathan

    2015-07-15

    The maturation of cortical structures, and the establishment of their connectivity, are critical neurodevelopmental processes that support and enable cognitive and behavioral functioning. Measures of cortical development, including thickness, curvature, and gyrification have been extensively studied in older children, adolescents, and adults, revealing regional associations with cognitive performance, and alterations with disease or pathology. In addition to these gross morphometric measures, increased attention has recently focused on quantifying more specific indices of cortical structure, in particular intracortical myelination, and their relationship to cognitive skills, including IQ, executive functioning, and language performance. Here we analyze the progression of cortical myelination across early childhood, from 1 to 6 years of age, in vivo for the first time. Using two quantitative imaging techniques, namely T1 relaxation time and myelin water fraction (MWF) imaging, we characterize myelination throughout the cortex, examine developmental trends, and investigate hemispheric and gender-based differences. We present a pattern of cortical myelination that broadly mirrors established histological timelines, with somatosensory, motor and visual cortices myelinating by 1 year of age; and frontal and temporal cortices exhibiting more protracted myelination. Developmental trajectories, defined by logarithmic functions (increasing for MWF, decreasing for T1), were characterized for each of 68 cortical regions. Comparisons of trajectories between hemispheres and gender revealed no significant differences. Results illustrate the ability to quantitatively map cortical myelination throughout early neurodevelopment, and may provide an important new tool for investigating typical and atypical development. Copyright © 2015. Published by Elsevier Inc.

  20. Cortical Thickness Abnormalities in Late Adolescence with Online Gaming Addiction

    Science.gov (United States)

    Yuan, Kai; Cheng, Ping; Dong, Tao; Bi, Yanzhi; Xing, Lihong; Yu, Dahua; Zhao, Limei; Dong, Minghao; von Deneen, Karen M.; Liu, Yijun; Qin, Wei; Tian, Jie

    2013-01-01

    Online gaming addiction, as the most popular subtype of Internet addiction, had gained more and more attention from the whole world. However, the structural differences in cortical thickness of the brain between adolescents with online gaming addiction and healthy controls are not well unknown; neither was its association with the impaired cognitive control ability. High-resolution magnetic resonance imaging scans from late adolescence with online gaming addiction (n = 18) and age-, education- and gender-matched controls (n = 18) were acquired. The cortical thickness measurement method was employed to investigate alterations of cortical thickness in individuals with online gaming addiction. The color-word Stroop task was employed to investigate the functional implications of the cortical thickness abnormalities. Imaging data revealed increased cortical thickness in the left precentral cortex, precuneus, middle frontal cortex, inferior temporal and middle temporal cortices in late adolescence with online gaming addiction; meanwhile, the cortical thicknesses of the left lateral orbitofrontal cortex (OFC), insula, lingual gyrus, the right postcentral gyrus, entorhinal cortex and inferior parietal cortex were decreased. Correlation analysis demonstrated that the cortical thicknesses of the left precentral cortex, precuneus and lingual gyrus correlated with duration of online gaming addiction and the cortical thickness of the OFC correlated with the impaired task performance during the color-word Stroop task in adolescents with online gaming addiction. The findings in the current study suggested that the cortical thickness abnormalities of these regions may be implicated in the underlying pathophysiology of online gaming addiction. PMID:23326379

  1. Cortical thickness abnormalities in late adolescence with online gaming addiction.

    Science.gov (United States)

    Yuan, Kai; Cheng, Ping; Dong, Tao; Bi, Yanzhi; Xing, Lihong; Yu, Dahua; Zhao, Limei; Dong, Minghao; von Deneen, Karen M; Liu, Yijun; Qin, Wei; Tian, Jie

    2013-01-01

    Online gaming addiction, as the most popular subtype of Internet addiction, had gained more and more attention from the whole world. However, the structural differences in cortical thickness of the brain between adolescents with online gaming addiction and healthy controls are not well unknown; neither was its association with the impaired cognitive control ability. High-resolution magnetic resonance imaging scans from late adolescence with online gaming addiction (n = 18) and age-, education- and gender-matched controls (n = 18) were acquired. The cortical thickness measurement method was employed to investigate alterations of cortical thickness in individuals with online gaming addiction. The color-word Stroop task was employed to investigate the functional implications of the cortical thickness abnormalities. Imaging data revealed increased cortical thickness in the left precentral cortex, precuneus, middle frontal cortex, inferior temporal and middle temporal cortices in late adolescence with online gaming addiction; meanwhile, the cortical thicknesses of the left lateral orbitofrontal cortex (OFC), insula, lingual gyrus, the right postcentral gyrus, entorhinal cortex and inferior parietal cortex were decreased. Correlation analysis demonstrated that the cortical thicknesses of the left precentral cortex, precuneus and lingual gyrus correlated with duration of online gaming addiction and the cortical thickness of the OFC correlated with the impaired task performance during the color-word Stroop task in adolescents with online gaming addiction. The findings in the current study suggested that the cortical thickness abnormalities of these regions may be implicated in the underlying pathophysiology of online gaming addiction.

  2. Cortical thickness abnormalities in late adolescence with online gaming addiction.

    Directory of Open Access Journals (Sweden)

    Kai Yuan

    Full Text Available Online gaming addiction, as the most popular subtype of Internet addiction, had gained more and more attention from the whole world. However, the structural differences in cortical thickness of the brain between adolescents with online gaming addiction and healthy controls are not well unknown; neither was its association with the impaired cognitive control ability. High-resolution magnetic resonance imaging scans from late adolescence with online gaming addiction (n = 18 and age-, education- and gender-matched controls (n = 18 were acquired. The cortical thickness measurement method was employed to investigate alterations of cortical thickness in individuals with online gaming addiction. The color-word Stroop task was employed to investigate the functional implications of the cortical thickness abnormalities. Imaging data revealed increased cortical thickness in the left precentral cortex, precuneus, middle frontal cortex, inferior temporal and middle temporal cortices in late adolescence with online gaming addiction; meanwhile, the cortical thicknesses of the left lateral orbitofrontal cortex (OFC, insula, lingual gyrus, the right postcentral gyrus, entorhinal cortex and inferior parietal cortex were decreased. Correlation analysis demonstrated that the cortical thicknesses of the left precentral cortex, precuneus and lingual gyrus correlated with duration of online gaming addiction and the cortical thickness of the OFC correlated with the impaired task performance during the color-word Stroop task in adolescents with online gaming addiction. The findings in the current study suggested that the cortical thickness abnormalities of these regions may be implicated in the underlying pathophysiology of online gaming addiction.

  3. Cortical gyrification is abnormal in children with prenatal alcohol exposure.

    Science.gov (United States)

    Hendrickson, Timothy J; Mueller, Bryon A; Sowell, Elizabeth R; Mattson, Sarah N; Coles, Claire D; Kable, Julie A; Jones, Kenneth L; Boys, Christopher J; Lim, Kelvin O; Riley, Edward P; Wozniak, Jeffrey R

    2017-01-01

    Prenatal alcohol exposure (PAE) adversely affects early brain development. Previous studies have shown a wide range of structural and functional abnormalities in children and adolescents with PAE. The current study adds to the existing literature specifically on cortical development by examining cortical gyrification in a large sample of children with PAE compared to controls. Relationships between cortical development and intellectual functioning are also examined. Included were 92 children with PAE and 83 controls ages 9-16 from four sites in the Collaborative Initiative on FASD (CIFASD). All PAE participants had documented heavy PAE. All underwent a formal evaluation of physical anomalies and dysmorphic facial features. MRI data were collected using modified matched protocols on three platforms (Siemens, GE, and Philips). Cortical gyrification was examined using a semi-automated procedure. Whole brain group comparisons using Monte Carlo z-simulation for multiple comparisons showed significantly lower cortical gyrification across a large proportion of the cerebral cortex amongst PAE compared to controls. Whole brain comparisons and ROI based analyses showed strong positive correlations between cortical gyrification and IQ (i.e. less developed cortex was associated with lower IQ). Abnormalities in cortical development were seen across the brain in children with PAE compared to controls. Cortical gyrification and IQ were strongly correlated, suggesting that examining mechanisms by which alcohol disrupts cortical formation may yield clinically relevant insights and potential directions for early intervention.

  4. SLEEP AND OLFACTORY CORTICAL PLASTICITY

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    Dylan eBarnes

    2014-04-01

    Full Text Available In many systems, sleep plays a vital role in memory consolidation and synaptic homeostasis. These processes together help store information of biological significance and reset synaptic circuits to facilitate acquisition of information in the future. In this review, we describe recent evidence of sleep-dependent changes in olfactory system structure and function which contribute to odor memory and perception. During slow-wave sleep, the piriform cortex becomes hypo-responsive to odor stimulation and instead displays sharp-wave activity similar to that observed within the hippocampal formation. Furthermore, the functional connectivity between the piriform cortex and other cortical and limbic regions is enhanced during slow-wave sleep compared to waking. This combination of conditions may allow odor memory consolidation to occur during a state of reduced external interference and facilitate association of odor memories with stored hedonic and contextual cues. Evidence consistent with sleep-dependent odor replay within olfactory cortical circuits is presented. These data suggest that both the strength and precision of odor memories is sleep-dependent. The work further emphasizes the critical role of synaptic plasticity and memory in not only odor memory but also basic odor perception. The work also suggests a possible link between sleep disturbances that are frequently co-morbid with a wide range of pathologies including Alzheimer’s disease, schizophrenia and depression and the known olfactory impairments associated with those disorders.

  5. Spreading effect of tDCS in individuals with attention-deficit/hyperactivity disorder as shown by functional cortical networks: a randomized, double-blind, sham-controlled trial

    Directory of Open Access Journals (Sweden)

    Camila eCosmo

    2015-08-01

    Full Text Available Transcranial direct current stimulation (tDCS is known to modulate spontaneous neural network excitability. The cognitive improvement observed in previous trials raises the potential of this technique as a possible therapeutic tool for use in attention-deficit/hyperactivity disorder (ADHD population. However, to explore the potential of this technique as a treatment approach the functional parameters of brain connectivity and the extent of its effects need to be more fully investigated.The aim of this study was to investigate a functional cortical network model based on electroencephalographic activity for studying the dynamic patterns of brain connectivity modulated by tDCS and the distribution of its effects in individuals with attention-deficit/hyperactivity disorder (ADHD.Sixty ADHD patients participated in a parallel, randomized, double-blind, sham-controlled trial. Individuals underwent a single session of sham or anodal tDCS at 1 mA of current intensity over the left dorsolateral prefrontal cortex for 20 minutes. The acute effects of stimulation on brain connectivity were assessed using the functional cortical network model based on electroencephalography (EEG activity.Comparing the weighted node degree within groups prior to and following the intervention, a statistically significant difference was found in the electrodes located on the target and correlated areas in the active group (p<0.05, while no statistically significant results were found in the sham group (p ≥0.05; paired-sample Wilcoxon signed rank test. Anodal tDCS increased functional brain connectivity in individuals with ADHD compared to data recorded in the baseline resting state. In addition, although some studies have suggested that the effects of tDCS are selective, the present findings show that its modulatory activity spreads. Further studies need to be performed to investigate the dynamic patterns and physiological mechanisms underlying the modulatory effects of tDCS.

  6. Cortical Gyrification Patterns Associated with Trait Anxiety.

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    Tara A Miskovich

    Full Text Available Dispositional anxiety is a stable personality trait that is a key risk factor for internalizing disorders, and understanding the neural correlates of trait anxiety may help us better understand the development of these disorders. Abnormal cortical folding is thought to reflect differences in cortical connectivity occurring during brain development. Therefore, assessing gyrification may advance understanding of cortical development and organization associated with trait anxiety. Previous literature has revealed structural abnormalities in trait anxiety and related disorders, but no study to our knowledge has examined gyrification in trait anxiety. We utilized a relatively novel measure, the local gyrification index (LGI, to explore differences in gyrification as a function of trait anxiety. We obtained structural MRI scans using a 3T magnetic resonance scanner on 113 young adults. Results indicated a negative correlation between trait anxiety and LGI in the left superior parietal cortex, specifically the precuneus, reflecting less cortical complexity among those high on trait anxiety. Our findings suggest that aberrations in cortical gyrification in a key region of the default mode network is a correlate of trait anxiety and may reflect disrupted local parietal connectivity.

  7. Análise da distribuição de potência cortical em função do aprendizado de datilografia Analisis da distribuición de potencia cortical en función del aprendizado de dactilografia Analysis of cortical power distribution as a function of the typewriting skill

    Directory of Open Access Journals (Sweden)

    Victor Hugo Bastos

    2004-12-01

    Full Text Available O objetivo do presente estudo foi investigar alterações nos padrões eletroencefalográficos de sujeitos normais e destros durante o aprendizado motor de uma tarefa manual. Estudos recentes têm demonstrado que o córtex cerebral é suscetível a modificações em vários aspectos durante a aprendizagem e que tais alterações nos padrões eletrocorticais são resultado da aquisição de habilidades motoras e consolidação de memória. Para tal, a atividade elétrica cortical dos sujeitos foi analisada antes e depois da prática motora. Os dados foram captados pelo Braintech 3000 e analisados pelo programa Neurometrics. Para a análise estatística, variáveis comportamentais tais como tempo e erro foram observadas através de uma ANOVA one-way, blocos como efeito principal. Na variável neurofisiológica, potência absoluta, foi utilizado um teste t pareado a fim de detectar alterações entre os momentos pré e pós-aprendizagem, e diferentes eletrodos, CZ-C3/CZ-C4 em teta e alfa, e O1-P3/T3-F7 em beta. Os resultados principais demonstraram mudança na performance através das variáveis tempo e número de erros. Concomitantemente, foi verificado aumento de potência na banda alfa sobre áreas centrais (CZ-C3/CZ-C4 e diminuição em beta localizada na área temporoparietal esquerda (O1-P3/T3-F7. Alterações na banda teta, como demonstradas em outros experimentos, não ocorreram neste estudo. Tais resultados sugerem uma adaptação do córtex sensório-motor em que a alteração da atividade elétrica cortical é condizente com uma transição ao automatismo motor.El objetivo del presente estudio fue el de investigar alteraciones en los padrones electroencefalográficos de sujetos normales y diestros durante el aprendizaje motor de una tarea manual Estudios recientes tienen demostrado que en el cortex cervical es susceptible a varias modificaciones en varios aspectos durante el aprendizaje, y que tales alteraciones en los padrones

  8. Cushing, Penfield, and cortical stimulation.

    Science.gov (United States)

    Leblanc, Richard

    2018-01-26

    Harvey Cushing and Wilder Penfield enjoyed a unique professional and personal relationship. Shortly before his retirement from Harvard University in 1933, Cushing sent Penfield 8 sketches that he drew in 1902 and 1903 while he was at Johns Hopkins Hospital. The first series of 3 sketches illustrate the relationship between a cortical hemorrhagic lesion and the motor strip in a patient with focal motor seizures. The second series also comprises 3 sketches. These depict the operative findings in a patient in whom Cushing had electrically stimulated the precentral gyrus, before resecting the cortex subserving motility of the upper extremity to control painful dyskinetic movements. The third series consists of 2 sketches that illustrate the results of stimulation of the motor strip as an aid in the safe resection of an epileptogenic focus in a patient with Jacksonian seizures. These sketches are the subjects of this paper. They add to the relatively sparse record of Cushing's activities in cortical stimulation and in the treatment of functional disorders.

  9. Cortical and spinal assessment

    DEFF Research Database (Denmark)

    Fischer, I W; Gram, Mikkel; Hansen, T M

    2017-01-01

    BACKGROUND: Standardized objective methods to assess the analgesic effects of opioids, enable identification of underlying mechanisms of drug actions in the central nervous system. Opioids may exert their effect on both cortical and spinal levels. In this study actions of morphine at both levels...... were investigated, followed by analysis of a possible correlation between the cortical processing and spinal transmission. METHODS: The study was conducted after a double-blinded, two-way crossover design in thirty-nine healthy participants. Each participant received 30mg morphine or placebo as oral...... morphine administration (P>0.05). CONCLUSIONS: Cold pressor EEG and the nociceptive reflex were more sensitive to morphine analgesia than resting EEG and can be used as standardized objective methods to assess opioid effects. However, no correlation between the analgesic effect of morphine on the spinal...

  10. Early and phasic cortical metabolic changes in vestibular neuritis onset.

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    Marco Alessandrini

    Full Text Available Functional brain activation studies described the presence of separate cortical areas responsible for central processing of peripheral vestibular information and reported their activation and interactions with other sensory modalities and the changes of this network associated to strategic peripheral or central vestibular lesions. It is already known that cortical changes induced by acute unilateral vestibular failure (UVF are various and undergo variations over time, revealing different cortical involved areas at the onset and recovery from symptoms. The present study aimed at reporting the earliest change in cortical metabolic activity during a paradigmatic form of UVF such as vestibular neuritis (VN, that is, a purely peripheral lesion of the vestibular system, that offers the opportunity to study the cortical response to altered vestibular processing. This research reports [(18F]fluorodeoxyglucose positron emission tomography brain scan data concerning the early cortical metabolic activity associated to symptoms onset in a group of eight patients suffering from VN. VN patients' cortical metabolic activity during the first two days from symptoms onset was compared to that recorded one month later and to a control healthy group. Beside the known cortical response in the sensorimotor network associated to vestibular deafferentation, we show for the first time the involvement of Entorhinal (BAs 28, 34 and Temporal (BA 38 cortices in early phases of symptomatology onset. We interpret these findings as the cortical counterparts of the attempt to reorient oneself in space counteracting the vertigo symptom (Bas 28, 34 and of the emotional response to the new pathologic condition (BA 38 respectively. These interpretations were further supported by changes in patients' subjective ratings in balance, anxiety, and depersonalization/derealization scores when tested at illness onset and one month later. The present findings contribute in expanding

  11. Effect of age at onset on cortical thickness and cognition in posterior cortical atrophy.

    Science.gov (United States)

    Suárez-González, Aida; Lehmann, Manja; Shakespeare, Timothy J; Yong, Keir X X; Paterson, Ross W; Slattery, Catherine F; Foulkes, Alexander J M; Rabinovici, Gil D; Gil-Néciga, Eulogio; Roldán-Lora, Florinda; Schott, Jonathan M; Fox, Nick C; Crutch, Sebastian J

    2016-08-01

    Age at onset (AAO) has been shown to influence the phenotype of Alzheimer's disease (AD), but how it affects atypical presentations of AD remains unknown. Posterior cortical atrophy (PCA) is the most common form of atypical AD. In this study, we aimed to investigate the effect of AAO on cortical thickness and cognitive function in 98 PCA patients. We used Freesurfer (v5.3.0) to compare cortical thickness with AAO both as a continuous variable, and by dichotomizing the groups based on median age (58 years). In both the continuous and dichotomized analyses, we found a pattern suggestive of thinner cortex in precuneus and parietal areas in earlier-onset PCA, and lower cortical thickness in anterior cingulate and prefrontal cortex in later-onset PCA. These cortical thickness differences between PCA subgroups were consistent with earlier-onset PCA patients performing worse on cognitive tests involving parietal functions. Our results provide a suggestion that AAO may not only affect the clinico-anatomical characteristics in AD but may also affect atrophy patterns and cognition within atypical AD phenotypes. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  12. Early adolescent cortical thinning is related to better neuropsychological performance.

    Science.gov (United States)

    Squeglia, Lindsay M; Jacobus, Joanna; Sorg, Scott F; Jernigan, Terry L; Tapert, Susan F

    2013-10-01

    Adolescence is characterized by significant neuromaturation, including extensive cortical thinning, particularly in frontal regions. The goal of this study was to examine the behavioral correlates of neurostructural development in early adolescence. Participants were 185 healthy 12- to 14-year-olds (44% female) recruited from local schools. Participants completed a comprehensive neuropsychological test battery and magnetic resonance imaging session. Cortical surface reconstruction and thickness estimates were performed via FreeSurfer. Age and cortical thickness were negatively correlated in 10 brain regions, 7 of which were in frontal areas (β = −.15 to −.25, ps ≤ .05). Hierarchical linear regressions examined the influence of cortical thickness on working memory, attention, verbal learning and memory, visuospatial functioning, spatial planning and problem solving, and inhibition, controlling for age and intracranial volume. Thinner parietal cortices predicted better performances on tests of verbal learning and memory, visuospatial functioning, and spatial planning and problem solving (β = −.14 to −.24, ps ≤ .05). Age, spanning from 12 to 14 years, accounted for up to 6% of cortical thickness, suggesting substantial thinning during early adolescence, with males showing more accelerated thinning than females between ages 12 and 14. For both males and females, thinner parietal association cortices corresponded with better neurocognitive functioning above and beyond age alone.

  13. Lhx2 regulates the timing of β-catenin-dependent cortical neurogenesis.

    Science.gov (United States)

    Hsu, Lea Chia-Ling; Nam, Sean; Cui, Yi; Chang, Ching-Pu; Wang, Chia-Fang; Kuo, Hung-Chih; Touboul, Jonathan D; Chou, Shen-Ju

    2015-09-29

    The timing of cortical neurogenesis has a major effect on the size and organization of the mature cortex. The deletion of the LIM-homeodomain transcription factor Lhx2 in cortical progenitors by Nestin-cre leads to a dramatically smaller cortex. Here we report that Lhx2 regulates the cortex size by maintaining the cortical progenitor proliferation and delaying the initiation of neurogenesis. The loss of Lhx2 in cortical progenitors results in precocious radial glia differentiation and a temporal shift of cortical neurogenesis. We further investigated the underlying mechanisms at play and demonstrated that in the absence of Lhx2, the Wnt/β-catenin pathway failed to maintain progenitor proliferation. We developed and applied a mathematical model that reveals how precocious neurogenesis affected cortical surface and thickness. Thus, we concluded that Lhx2 is required for β-catenin function in maintaining cortical progenitor proliferation and controls the timing of cortical neurogenesis.

  14. Cerebellar cortical infarct cavities and vertebral artery disease

    Energy Technology Data Exchange (ETDEWEB)

    Cocker, Laurens J.L. de [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Kliniek Sint-Jan Radiologie, Brussels (Belgium); Compter, A.; Kappelle, L.J.; Worp, H.B. van der [University Medical Center Utrecht, Department of Neurology and Neurosurgery, Brain Center Rudolf Magnus, Utrecht (Netherlands); Luijten, P.R.; Hendrikse, J. [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands)

    2016-09-15

    Cerebellar cortical infarct cavities are a newly recognised entity associated with atherothromboembolic cerebrovascular disease and worse physical functioning. We aimed to investigate the relationship of cerebellar cortical infarct cavities with symptomatic vertebrobasilar ischaemia and with vascular risk factors. We evaluated the MR images of 46 patients with a recent vertebrobasilar TIA or stroke and a symptomatic vertebral artery stenosis ≥50 % from the Vertebral Artery Stenting Trial (VAST) for the presence of cerebellar cortical infarct cavities ≤1.5 cm. At inclusion in VAST, data were obtained on age, sex, history of vertebrobasilar TIA or stroke, and vascular risk factors. Adjusted risk ratios were calculated with Poisson regression analyses for the relation between cerebellar cortical infarct cavities and vascular risk factors. Sixteen out of 46 (35 %) patients showed cerebellar cortical infarct cavities on the initial MRI, and only one of these 16 patients was known with a previous vertebrobasilar TIA or stroke. In patients with symptomatic vertebrobasilar ischaemia, risk factor profiles of patients with cerebellar cortical infarct cavities were not different from patients without these cavities. Cerebellar cortical infarct cavities are seen on MRI in as much as one third of patients with recently symptomatic vertebral artery stenosis. Since patients usually have no prior history of vertebrobasilar TIA or stroke, cerebellar cortical infarct cavities should be added to the spectrum of common incidental brain infarcts visible on routine MRI. (orig.)

  15. The biology and dynamics of mammalian cortical granules

    Science.gov (United States)

    2011-01-01

    Cortical granules are membrane bound organelles located in the cortex of unfertilized oocytes. Following fertilization, cortical granules undergo exocytosis to release their contents into the perivitelline space. This secretory process, which is calcium dependent and SNARE protein-mediated pathway, is known as the cortical reaction. After exocytosis, the released cortical granule proteins are responsible for blocking polyspermy by modifying the oocytes' extracellular matrices, such as the zona pellucida in mammals. Mammalian cortical granules range in size from 0.2 um to 0.6 um in diameter and different from most other regulatory secretory organelles in that they are not renewed once released. These granules are only synthesized in female germ cells and transform an egg upon sperm entry; therefore, this unique cellular structure has inherent interest for our understanding of the biology of fertilization. Cortical granules are long thought to be static and awaiting in the cortex of unfertilized oocytes to be stimulated undergoing exocytosis upon gamete fusion. Not till recently, the dynamic nature of cortical granules is appreciated and understood. The latest studies of mammalian cortical granules document that this organelle is not only biochemically heterogeneous, but also displays complex distribution during oocyte development. Interestingly, some cortical granules undergo exocytosis prior to fertilization; and a number of granule components function beyond the time of fertilization in regulating embryonic cleavage and preimplantation development, demonstrating their functional significance in fertilization as well as early embryonic development. The following review will present studies that investigate the biology of cortical granules and will also discuss new findings that uncover the dynamic aspect of this organelle in mammals. PMID:22088197

  16. The biology and dynamics of mammalian cortical granules

    Directory of Open Access Journals (Sweden)

    Liu Min

    2011-11-01

    Full Text Available Abstract Cortical granules are membrane bound organelles located in the cortex of unfertilized oocytes. Following fertilization, cortical granules undergo exocytosis to release their contents into the perivitelline space. This secretory process, which is calcium dependent and SNARE protein-mediated pathway, is known as the cortical reaction. After exocytosis, the released cortical granule proteins are responsible for blocking polyspermy by modifying the oocytes' extracellular matrices, such as the zona pellucida in mammals. Mammalian cortical granules range in size from 0.2 um to 0.6 um in diameter and different from most other regulatory secretory organelles in that they are not renewed once released. These granules are only synthesized in female germ cells and transform an egg upon sperm entry; therefore, this unique cellular structure has inherent interest for our understanding of the biology of fertilization. Cortical granules are long thought to be static and awaiting in the cortex of unfertilized oocytes to be stimulated undergoing exocytosis upon gamete fusion. Not till recently, the dynamic nature of cortical granules is appreciated and understood. The latest studies of mammalian cortical granules document that this organelle is not only biochemically heterogeneous, but also displays complex distribution during oocyte development. Interestingly, some cortical granules undergo exocytosis prior to fertilization; and a number of granule components function beyond the time of fertilization in regulating embryonic cleavage and preimplantation development, demonstrating their functional significance in fertilization as well as early embryonic development. The following review will present studies that investigate the biology of cortical granules and will also discuss new findings that uncover the dynamic aspect of this organelle in mammals.

  17. Distinct expression/function of potassium and chloride channels contributes to the diverse volume regulation in cortical astrocytes of GFAP/EGFP mice.

    Directory of Open Access Journals (Sweden)

    Jana Benesova

    changes displayed by cortical astrocytes during OGD mainly result from their distinct expression patterns of ClC2 and K(2P channels.

  18. Cortical pathology in multiple sclerosis.

    Science.gov (United States)

    Stadelmann, Christine; Albert, Monika; Wegner, Christiane; Brück, Wolfgang

    2008-06-01

    Multiple sclerosis is the most common chronic, disabling central nervous system disease in young adults, characterized by inflammatory demyelinating white matter lesions with glial scar formation and axonal loss. Lately, evidence has accumulated that large areas of grey matter are affected in multiple sclerosis patients. Findings in post-mortem brain tissue support the notion that cortical demyelination is frequent and extensive, especially in patients with chronic multiple sclerosis. Cortical lesions differ from white matter lesions with respect to inflammatory cell infiltration, gliosis, and remyelination. Thus, differences in cortical and white matter lesion pathogenesis have been proposed. Experimental models suggest a decisive role for antimyelin antibodies in cortical demyelination. Topical studies focus on damage to neurons, dendrites, and synapses in cortical multiple sclerosis lesions. Improved imaging techniques for the detection of cortical lesions are currently developed and will provide the basis for future clinicopathological correlative studies. In summary, recent years have opened our eyes to the extensive grey matter involvement in multiple sclerosis. Studies on the pathogenesis of cortical demyelination, cortical damage, and repair will elucidate basic principles of multiple sclerosis lesion formation. However, more sensitive imaging tools are required to study the impact of cortical lesions on clinical symptoms, disability, and disease progression.

  19. Resection of cavernous angioma located in eloquent areas using functional cortical and subcortical mapping under awake conditions. Outcomes in a 50-case multicentre series.

    Science.gov (United States)

    Zanello, M; Wager, M; Corns, R; Capelle, L; Mandonnet, E; Fontaine, D; Reyns, N; Dezamis, E; Matsuda, R; Bresson, D; Duffau, H; Pallud, J

    2017-06-01

    Surgical resection of supratentorial cavernous angiomas located in eloquent areas poses a significant risk to the patient of postoperative neurological impairment and justifies intraoperative functional monitoring. Multicentre retrospective series of adult patients with cavernous angiomas located within eloquent areas and treated with functional-based surgical resection according to functional boundaries under intraoperative functional cortico-subcortical monitoring under awake conditions. Fifty patients (18 males, mean 36.3±10.8 year-old) underwent surgical resection with intraoperative cortico-subcortical functional mapping using direct electrostimulation under awake conditions for a cavernous angioma located in eloquent areas with a mean postoperative follow-up of 21.0±21.2 months. At presentation, the cavernous angioma had previously resulted in severe impairment (neurological deficit in 34%, seizures in 70%, uncontrolled seizures in 34%, reduced Karnofsky Performance Status score of 70 or less in 24%, inability to work in 52%). Functional-based surgical resection allowed complete removal of the cavernous angioma in 98% and of the haemosiderin rim in 82%. Postoperative seizures and other complications were rare, and similarly so across all centres included in this series. Postoperatively, we found functional improvement in 84% of patients (reduced Karnofsky Performance Status score of 70 or less in 6%, uncontrolled seizures in 16%, and inability to work in 11%). Functional-based surgical resection aids the safe and complete resection of cavernous angiomas located in eloquent areas while minimizing the surgical risks. Functional mapping has to be considered in such challenging cases. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  20. A Mechanistic Link from GABA to Cortical Architecture and Perception.

    Science.gov (United States)

    Kolasinski, James; Logan, John P; Hinson, Emily L; Manners, Daniel; Divanbeighi Zand, Amir P; Makin, Tamar R; Emir, Uzay E; Stagg, Charlotte J

    2017-06-05

    Understanding both the organization of the human cortex and its relation to the performance of distinct functions is fundamental in neuroscience. The primary sensory cortices display topographic organization, whereby receptive fields follow a characteristic pattern, from tonotopy to retinotopy to somatotopy [1]. GABAergic signaling is vital to the maintenance of cortical receptive fields [2]; however, it is unclear how this fine-grain inhibition relates to measurable patterns of perception [3, 4]. Based on perceptual changes following perturbation of the GABAergic system, it is conceivable that the resting level of cortical GABAergic tone directly relates to the spatial specificity of activation in response to a given input [5-7]. The specificity of cortical activation can be considered in terms of cortical tuning: greater cortical tuning yields more localized recruitment of cortical territory in response to a given input. We applied a combination of fMRI, MR spectroscopy, and psychophysics to substantiate the link between the cortical neurochemical milieu, the tuning of cortical activity, and variability in perceptual acuity, using human somatosensory cortex as a model. We provide data that explain human perceptual acuity in terms of both the underlying cellular and metabolic processes. Specifically, higher concentrations of sensorimotor GABA are associated with more selective cortical tuning, which in turn is associated with enhanced perception. These results show anatomical and neurochemical specificity and are replicated in an independent cohort. The mechanistic link from neurochemistry to perception provides a vital step in understanding population variability in sensory behavior, informing metabolic therapeutic interventions to restore perceptual abilities clinically. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  1. Adult Astrogenesis and the Etiology of Cortical Neurodegeneration

    Directory of Open Access Journals (Sweden)

    Tal C. Mohn

    2015-01-01

    Full Text Available As more evidence points to a clear role for astrocytes in synaptic processing, synaptogenesis and cognition, continuing research on astrocytic function could lead to strategies for neurodegenerative disease prevention. Reactive astrogliosis results in astrocyte proliferation early in injury and disease states and is considered neuroprotective, indicating a role for astrocytes in disease etiology. This review describes the different types of human cortical astrocytes and the current evidence regarding adult cortical astrogenesis in injury and degenerative disease. A role for disrupted astrogenesis as a cause of cortical degeneration, with a focus on the tauopathies and synucleinopathies, will also be considered.

  2. Cortico-cortical communication dynamics

    Directory of Open Access Journals (Sweden)

    Per E Roland

    2014-05-01

    Full Text Available IIn principle, cortico-cortical communication dynamics is simple: neurons in one cortical area communicate by sending action potentials that release glutamate and excite their target neurons in other cortical areas. In practice, knowledge about cortico-cortical communication dynamics is minute. One reason is that no current technique can capture the fast spatio-temporal cortico-cortical evolution of action potential transmission and membrane conductances with sufficient spatial resolution. A combination of optogenetics and monosynaptic tracing with virus can reveal the spatio-temporal cortico-cortical dynamics of specific neurons and their targets, but does not reveal how the dynamics evolves under natural conditions. Spontaneous ongoing action potentials also spread across cortical areas and are difficult to separate from structured evoked and intrinsic brain activity such as thinking. At a certain state of evolution, the dynamics may engage larger populations of neurons to drive the brain to decisions, percepts and behaviors. For example, successfully evolving dynamics to sensory transients can appear at the mesoscopic scale revealing how the transient is perceived. As a consequence of these methodological and conceptual difficulties, studies in this field comprise a wide range of computational models, large-scale measurements (e.g., by MEG, EEG, and a combination of invasive measurements in animal experiments. Further obstacles and challenges of studying cortico-cortical communication dynamics are outlined in this critical review.

  3. Environmental enrichment aides in functional recovery following unilateral controlled cortical impact of the forelimb sensorimotor area however intranasal administration of nerve growth factor does not.

    Science.gov (United States)

    Young, Jennica; Pionk, Timothy; Hiatt, Ivy; Geeck, Katalin; Smith, Jeffrey S

    2015-06-01

    An injury to the forelimb sensorimotor cortex results in the impairment of motor function in animals. Recent research has suggested that intranasal administration of nerve growth factor (NGF), a protein naturally found in the brain, and placement into enriched environments (EE) improves motor and cognitive function after traumatic brain injury (TBI). The purpose of this study was to determine whether NGF, EE, or the combination of both was beneficial in the recovery of motor function following TBI. Uninjured animals had fewer foot faults than injured animals, displaying a lesion effect. Injured animals housed in EE were shown to have fewer foot faults whether or not they received NGF. Injured animals also displayed an increased reliance on the non-impaired limb further validating a lesion effect. EE is an effective treatment on the recovery of motor function after a TBI. Intranasal administration of NGF was found to not be an effective treatment for functional motor recovery after a TBI. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Retrosplenial cortical thinning as a possible major contributor for cognitive impairment in HIV patients

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Na-Young [The Catholic University of Korea, Department of Radiology, College of Medicine, Seoul (Korea, Republic of); Hong, Jinwoo; Yoon, Uicheul [Catholic University of Daegu, Department of Biomedical Engineering, College of Health and Medical Science, Gyeongsan-si, Gyeongbuk (Korea, Republic of); Choi, Jun Yong [Yonsei University College of Medicine, Department of Internal Medicine and AIDS Research Institute, Seoul (Korea, Republic of); Lee, Seung-Koo [Yonsei University College of Medicine, Department of Radiology, Seoul (Korea, Republic of); Lim, Soo Mee [Ewha Womans University, School of Medicine, Department of Radiology, Seoul (Korea, Republic of)

    2017-11-15

    To identify brain cortical regions relevant to HIV-associated neurocognitive disorder (HAND) in HIV patients. HIV patients with HAND (n = 10), those with intact cognition (HIV-IC; n = 12), and age-matched, seronegative controls (n = 11) were recruited. All participants were male and underwent 3-dimensional T1-weighted imaging. Both vertex-wise and region of interest (ROI) analyses were performed to analyse cortical thickness. Compared to controls, both HIV-IC and HAND showed decreased cortical thickness mainly in the bilateral primary sensorimotor areas, extending to the prefrontal and parietal cortices. When directly comparing HIV-IC and HAND, HAND showed cortical thinning in the left retrosplenial cortex, left dorsolateral prefrontal cortex, left inferior parietal lobule, bilateral superior medial prefrontal cortices, right temporoparietal junction and left hippocampus, and cortical thickening in the left middle occipital cortex. Left retrosplenial cortical thinning showed significant correlation with slower information processing, declined verbal memory and executive function, and impaired fine motor skills. This study supports previous research suggesting the selective vulnerability of the primary sensorimotor cortices and associations between cortical thinning in the prefrontal and parietal cortices and cognitive impairment in HIV-infected patients. Furthermore, for the first time, we propose retrosplenial cortical thinning as a possible major contributor to HIV-associated cognitive impairment. (orig.)

  5. Atypical prefrontal cortical responses to joint/non-joint attention in children with autism spectrum disorder (ASD): A functional near-infrared spectroscopy study

    Science.gov (United States)

    Zhu, Huilin; Li, Jun; Fan, Yuebo; Li, Xinge; Huang, Dan; He, Sailing

    2015-01-01

    Autism spectrum disorder (ASD) is a neuro-developmental disorder, characterized by impairments in one’s capacity for joint attention. In this study, functional near-infrared spectroscopy (fNIRS) was applied to study the differences in activation and functional connectivity in the prefrontal cortex between children with autism spectrum disorder (ASD) and typically developing (TD) children. 21 ASD and 20 TD children were recruited to perform joint and non-joint attention tasks. Compared with TD children, children with ASD showed reduced activation and atypical functional connectivity pattern in the prefrontal cortex during joint attention. The atypical development of left prefrontal cortex might play an important role in social cognition defects of children with ASD. PMID:25798296

  6. Gradients of cortical hierarchy in Autism

    Directory of Open Access Journals (Sweden)

    Richard Bethlehem

    2017-05-01

    Full Text Available Autism is a developmental condition associated with altered functional connectivity. We propose to re-frame the functional connectivity alterations in terms of gradients that capture the functional hierarchy of cortical processing from sensory to default-mode network regions. We hypothesized that this hierarchy will be altered in ASD. To test that, we compared the scale of gradients in people with autism and healthy controls. The present results do not support our hypothesis. There are two alternative implications: either the processing hierarchies are preserved in autism or the scale of the gradients does not capture them. In the future we will attempt to settle which alternative is more likely.

  7. Cortical neural prosthetics.

    Science.gov (United States)

    Schwartz, Andrew B

    2004-01-01

    Control of prostheses using cortical signals is based on three elements: chronic microelectrode arrays, extraction algorithms, and prosthetic effectors. Arrays of microelectrodes are permanently implanted in cerebral cortex. These arrays must record populations of single- and multiunit activity indefinitely. Information containing position and velocity correlates of animate movement needs to be extracted continuously in real time from the recorded activity. Prosthetic arms, the current effectors used in this work, need to have the agility and configuration of natural arms. Demonstrations using closed-loop control show that subjects change their neural activity to improve performance with these devices. Adaptive-learning algorithms that capitalize on these improvements show that this technology has the capability of restoring much of the arm movement lost with immobilizing deficits.

  8. Cortical layers: Cyto-, myelo-, receptor- and synaptic architecture in human cortical areas.

    Science.gov (United States)

    Palomero-Gallagher, Nicola; Zilles, Karl

    2017-08-12

    Cortical layers have classically been identified by their distinctive and prevailing cell types and sizes, as well as the packing densities of cell bodies or myelinated fibers. The densities of multiple receptors for classical neurotransmitters also vary across the depth of the cortical ribbon, and thus determine the neurochemical properties of cyto- and myeloarchitectonic layers. However, a systematic comparison of the correlations between these histologically definable layers and the laminar distribution of transmitter receptors is currently lacking. We here analyze the densities of 17 different receptors of various transmitter systems in the layers of eight cytoarchitectonically identified, functionally (motor, sensory, multimodal) and hierarchically (primary and secondary sensory, association) distinct areas of the human cerebral cortex. Maxima of receptor densities are found in different layers when comparing different cortical regions, i.e. laminar receptor densities demonstrate differences in receptorarchitecture between isocortical areas, notably between motor and primary sensory cortices, specifically the primary visual and somatosensory cortices, as well as between allocortical and isocortical areas. Moreover, considerable differences are found between cytoarchitectonical and receptor architectonical laminar patterns. Whereas the borders of cyto- and myeloarchitectonic layers are well comparable, the laminar profiles of receptor densities rarely coincide with the histologically defined borders of layers. Instead, highest densities of most receptors are found where the synaptic density is maximal, i.e. in the supragranular layers, particularly in layers II-III. The entorhinal cortex as an example of the allocortex shows a peculiar laminar organization, which largely deviates from that of all the other cortical areas analyzed here. Copyright © 2017. Published by Elsevier Inc.

  9. Intensive cognitive training in schizophrenia enhances working memory and associated prefrontal cortical efficiency in a manner that drives long-term functional gains.

    Science.gov (United States)

    Subramaniam, Karuna; Luks, Tracy L; Garrett, Coleman; Chung, Cleo; Fisher, Melissa; Nagarajan, Srikantan; Vinogradov, Sophia

    2014-10-01

    We investigated whether intensive computerized cognitive training in schizophrenia could improve working memory performance and increase signal efficiency of associated middle frontal gyri (MFG) circuits in a functionally meaningful manner. Thirty schizophrenia participants and 13 healthy comparison participants underwent fMRI scanning during a letter N-back working memory task. Schizophrenia participants were then randomly assigned to either 80 h (16 weeks) of cognitive training or a computer games control condition. After this intervention, participants completed a second fMRI N-back scanning session. At baseline, during 2-back working memory trials, healthy participants showed the largest and most significant activation in bilateral MFG, which correlated with task performance. Schizophrenia participants showed impaired working memory, hypoactivation in left MFG, and no correlation between bilateral MFG signal and task performance. After training, schizophrenia participants improved their 2-back working memory performance and showed increased activation in left MFG. They also demonstrated a significant association between enhanced task performance and right MFG signal, similar to healthy participants. Both task performance and brain activity in right MFG after training predicted better generalized working memory at 6-month follow-up. Furthermore, task performance and brain activity within bilateral MFG predicted better occupational functioning at 6-month follow-up. No such findings were observed in the computer games control participants. Working memory impairments in schizophrenia and its underlying neural correlates in MFG can be improved by intensive computerized cognitive training; these improvements generalize beyond the trained task and are associated with enduring effects on cognition and functioning 6 months after the intervention. Published by Elsevier Inc.

  10. Neuregulin 3 Mediates Cortical Plate Invasion and Laminar Allocation of GABAergic Interneurons

    Directory of Open Access Journals (Sweden)

    Giorgia Bartolini

    2017-01-01

    Full Text Available Neural circuits in the cerebral cortex consist of excitatory pyramidal cells and inhibitory interneurons. These two main classes of cortical neurons follow largely different genetic programs, yet they assemble into highly specialized circuits during development following a very precise choreography. Previous studies have shown that signals produced by pyramidal cells influence the migration of cortical interneurons, but the molecular nature of these factors has remained elusive. Here, we identified Neuregulin 3 (Nrg3 as a chemoattractive factor expressed by developing pyramidal cells that guides the allocation of cortical interneurons in the developing cortical plate. Gain- and loss-of-function approaches reveal that Nrg3 modulates the migration of interneurons into the cortical plate in a process that is dependent on the tyrosine kinase receptor ErbB4. Perturbation of Nrg3 signaling in conditional mutants leads to abnormal lamination of cortical interneurons. Nrg3 is therefore a critical mediator in the assembly of cortical inhibitory circuits.

  11. Visual Dysfunction in Posterior Cortical Atrophy

    Science.gov (United States)

    Maia da Silva, Mari N.; Millington, Rebecca S.; Bridge, Holly; James-Galton, Merle; Plant, Gordon T.

    2017-01-01

    Posterior cortical atrophy (PCA) is a syndromic diagnosis. It is characterized by progressive impairment of higher (cortical) visual function with imaging evidence of degeneration affecting the occipital, parietal, and posterior temporal lobes bilaterally. Most cases will prove to have Alzheimer pathology. The aim of this review is to summarize the development of the concept of this disorder since it was first introduced. A critical discussion of the evolving diagnostic criteria is presented and the differential diagnosis with regard to the underlying pathology is reviewed. Emphasis is given to the visual dysfunction that defines the disorder, and the classical deficits, such as simultanagnosia and visual agnosia, as well as the more recently recognized visual field defects, are reviewed, along with the evidence on their neural correlates. The latest developments on the imaging of PCA are summarized, with special attention to its role on the differential diagnosis with related conditions. PMID:28861031

  12. Visual Dysfunction in Posterior Cortical Atrophy.

    Science.gov (United States)

    Maia da Silva, Mari N; Millington, Rebecca S; Bridge, Holly; James-Galton, Merle; Plant, Gordon T

    2017-01-01

    Posterior cortical atrophy (PCA) is a syndromic diagnosis. It is characterized by progressive impairment of higher (cortical) visual function with imaging evidence of degeneration affecting the occipital, parietal, and posterior temporal lobes bilaterally. Most cases will prove to have Alzheimer pathology. The aim of this review is to summarize the development of the concept of this disorder since it was first introduced. A critical discussion of the evolving diagnostic criteria is presented and the differential diagnosis with regard to the underlying pathology is reviewed. Emphasis is given to the visual dysfunction that defines the disorder, and the classical deficits, such as simultanagnosia and visual agnosia, as well as the more recently recognized visual field defects, are reviewed, along with the evidence on their neural correlates. The latest developments on the imaging of PCA are summarized, with special attention to its role on the differential diagnosis with related conditions.

  13. Visual Dysfunction in Posterior Cortical Atrophy

    Directory of Open Access Journals (Sweden)

    Mari N. Maia da Silva

    2017-08-01

    Full Text Available Posterior cortical atrophy (PCA is a syndromic diagnosis. It is characterized by progressive impairment of higher (cortical visual function with imaging evidence of degeneration affecting the occipital, parietal, and posterior temporal lobes bilaterally. Most cases will prove to have Alzheimer pathology. The aim of this review is to summarize the development of the concept of this disorder since it was first introduced. A critical discussion of the evolving diagnostic criteria is presented and the differential diagnosis with regard to the underlying pathology is reviewed. Emphasis is given to the visual dysfunction that defines the disorder, and the classical deficits, such as simultanagnosia and visual agnosia, as well as the more recently recognized visual field defects, are reviewed, along with the evidence on their neural correlates. The latest developments on the imaging of PCA are summarized, with special attention to its role on the differential diagnosis with related conditions.

  14. Abnormalities in emotion processing within cortical and subcortical regions in criminal psychopaths: evidence from a functional magnetic resonance imaging study using pictures with emotional content.

    Science.gov (United States)

    Müller, Jürgen L; Sommer, Monika; Wagner, Verena; Lange, Kirsten; Taschler, Heidrun; Röder, Christian H; Schuierer, Gerhardt; Klein, Helmfried E; Hajak, Göran

    2003-07-15

    Neurobiology of psychopathy is important for our understanding of current neuropsychiatric questions. Despite a growing interest in biological research in psychopathy, its neural underpinning remains obscure. We used functional magnetic resonance imaging to study the influence of affective contents on brain activation in psychopaths. Series containing positive and negative pictures from the International Affective Picture System were shown to six male psychopaths and six male control subjects while 100 whole-brain echo-planar-imaging measurements were acquired. Differences in brain activation were evaluated using BrainVoyager software 4.6. In psychopaths, increased activation through negative contents was found right-sided in prefrontal regions and amygdala. Activation was reduced right-sided in the subgenual cingulate and the temporal gyrus, and left-sided in the dorsal cingulate and the parahippocampal gyrus. Increased activation through positive contents was found left-sided in the orbitofrontal regions. Activation was reduced in right medial frontal and medial temporal regions. These findings underline the hypotheses that psychopathy is neurobiologically reflected by dysregulation and disturbed functional connectivity of emotion-related brain regions. These findings may be interpreted within a framework including prefrontal regions that provide top-down control to and regulate bottom-up signals from limbic areas. Because of the small sample size, the results of this study have to be regarded as preliminary.

  15. Evaluation of cortical plasticity in children with cerebral palsy undergoing constraint-induced movement therapy based on functional near-infrared spectroscopy

    Science.gov (United States)

    Cao, Jianwei; Khan, Bilal; Hervey, Nathan; Tian, Fenghua; Delgado, Mauricio R.; Clegg, Nancy J.; Smith, Linsley; Roberts, Heather; Tulchin-Francis, Kirsten; Shierk, Angela; Shagman, Laura; MacFarlane, Duncan; Liu, Hanli; Alexandrakis, George

    2015-04-01

    Sensorimotor cortex plasticity induced by constraint-induced movement therapy (CIMT) in six children (10.2±2.1 years old) with hemiplegic cerebral palsy was assessed by functional near-infrared spectroscopy (fNIRS). The activation laterality index and time-to-peak/duration during a finger-tapping task and the resting-state functional connectivity were quantified before, immediately after, and 6 months after CIMT. These fNIRS-based metrics were used to help explain changes in clinical scores of manual performance obtained concurrently with imaging time points. Five age-matched healthy children (9.8±1.3 years old) were also imaged to provide comparative activation metrics for normal controls. Interestingly, the activation time-to-peak/duration for all sensorimotor centers displayed significant normalization immediately after CIMT that persisted 6 months later. In contrast to this improved localized activation response, the laterality index and resting-state connectivity metrics that depended on communication between sensorimotor centers improved immediately after CIMT, but relapsed 6 months later. In addition, for the subjects measured in this work, there was either a trade-off between improving unimanual versus bimanual performance when sensorimotor activation patterns normalized after CIMT, or an improvement occurred in both unimanual and bimanual performance but at the cost of very abnormal plastic changes in sensorimotor activity.

  16. Perinatal cortical growth and childhood neurocognitive abilities.

    Science.gov (United States)

    Rathbone, R; Counsell, S J; Kapellou, O; Dyet, L; Kennea, N; Hajnal, J; Allsop, J M; Cowan, F; Edwards, A D

    2011-10-18

    This observational cohort study addressed the hypothesis that after preterm delivery brain growth between 24 and 44 weeks postmenstrual age (PMA) is related to global neurocognitive ability in later childhood. Growth rates for cerebral volume and cortical surface area were estimated in 82 infants without focal brain lesions born before 30 weeks PMA by using 217 magnetic resonance images obtained between 24 and 44 weeks PMA. Abilities were assessed at 2 years using the Griffiths Mental Development Scale and at 6 years using the Wechsler Preschool and Primary Scale of Intelligence-Revised (WPPSI-R), the Developmental Neuropsychological Assessment (NEPSY), and the Movement Assessment Battery for Children (MABC). Analysis was by generalized least-squares regression. Mean test scores approximated population averages. Cortical growth was directly related to the Griffiths Developmental Quotient (DQ), the WPPSI-R full-scale IQ, and a NEPSY summary score but not the MABC score and in exploration of subtests to attention, planning, memory, language, and numeric and conceptual abilities but not motor skills. The mean (95% confidence interval) estimated reduction in cortical surface area at term corrected age associated with a 1 SD fall in test score was as follows: DQ 7.0 (5.8-8.5); IQ 6.0 (4.9-7.3); and NEPSY 9.1 (7.5-11.0) % · SD(-1). Total brain volume growth was not correlated with any test score. The rate of cerebral cortical growth between 24 and 44 weeks PMA predicts global ability in later childhood, particularly complex cognitive functions but not motor functions.

  17. Cortical-Cortical Interactions And Sensory Information Processing in Autism

    Science.gov (United States)

    2008-04-30

    Additionally, these cortical areas have been implicated from significantly elevated TOJ thresholds (worse performance) in subjects with dyslexia [5...of the fact that above-average TOJ thresholds occur in subjects with known damage to these same cortical areas ( dyslexia [5], dystonia [6-8], and...volumes in autistic boys . Brain 2003, 126:1182-1192. 32. Hollander E, Anagnostou E, Chaplin W, Esposito K, Haznedar MM, Licalzi E, Wasserman S, Soorya L

  18. Heidelberg Neuro-Music Therapy Restores Attention-Related Activity in the Angular Gyrus in Chronic Tinnitus Patients

    Science.gov (United States)

    Krick, Christoph M.; Argstatter, Heike; Grapp, Miriam; Plinkert, Peter K.; Reith, Wolfgang

    2017-01-01

    Background: Tinnitus is the perception of a phantom sound without external acoustic stimulation. Recent tinnitus research suggests a relationship between attention processes and tinnitus-related distress. It has been found that too much focus on tinnitus comes at the expense of the visual domain. The angular gyrus (AG) seems to play a crucial role in switching attention to the most salient stimulus. This study aims to evaluate the involvement of the AG during visual attention tasks in tinnitus sufferers treated with Heidelberg Neuro-Music Therapy (HNMT), an intervention that has been shown to reduce tinnitus-related distress. Methods: Thirty-three patients with chronic tinnitus, 45 patients with recent-onset tinnitus, and 35 healthy controls were tested. A fraction of these (21/21/22) were treated with the “compact” version of the HNMT lasting 1 week with intense treatments, while non-treated participants were included as passive controls. Visual attention was evaluated during functional Magnet-Resonance Imaging (fMRI) by a visual Continous Performance Task (CPT) using letter-based alarm cues (“O” and “X”) appearing in a sequence of neutral letters, “A” through “H.” Participants were instructed to respond via button press only if the letter “O” was followed by the letter “X” (GO condition), but not to respond if a neutral letter appeared instead (NOGO condition). All participants underwent two fMRI sessions, before and after a 1-week study period. Results: The CPT results revealed a relationship between error rates and tinnitus duration at baseline whereby the occurrence of erroneous “GO omissions” and the reaction time increased with tinnitus duration. Patients with chronic tinnitus who were treated with HNMT had decreasing error rates (fewer GO omissions) compared to treated recent-onset patients. fMRI analyses confirmed greater activation of the AG during CPT in chronic patients after HNMT treatment compared to treated recent

  19. Heidelberg Neuro-Music Therapy Restores Attention-Related Activity in the Angular Gyrus in Chronic Tinnitus Patients

    Directory of Open Access Journals (Sweden)

    Christoph M. Krick

    2017-07-01

    Full Text Available Background: Tinnitus is the perception of a phantom sound without external acoustic stimulation. Recent tinnitus research suggests a relationship between attention processes and tinnitus-related distress. It has been found that too much focus on tinnitus comes at the expense of the visual domain. The angular gyrus (AG seems to play a crucial role in switching attention to the most salient stimulus. This study aims to evaluate the involvement of the AG during visual attention tasks in tinnitus sufferers treated with Heidelberg Neuro-Music Therapy (HNMT, an intervention that has been shown to reduce tinnitus-related distress.Methods: Thirty-three patients with chronic tinnitus, 45 patients with recent-onset tinnitus, and 35 healthy controls were tested. A fraction of these (21/21/22 were treated with the “compact” version of the HNMT lasting 1 week with intense treatments, while non-treated participants were included as passive controls. Visual attention was evaluated during functional Magnet-Resonance Imaging (fMRI by a visual Continous Performance Task (CPT using letter-based alarm cues (“O” and “X” appearing in a sequence of neutral letters, “A” through “H.” Participants were instructed to respond via button press only if the letter “O” was followed by the letter “X” (GO condition, but not to respond if a neutral letter appeared instead (NOGO condition. All participants underwent two fMRI sessions, before and after a 1-week study period.Results: The CPT results revealed a relationship between error rates and tinnitus duration at baseline whereby the occurrence of erroneous “GO omissions” and the reaction time increased with tinnitus duration. Patients with chronic tinnitus who were treated with HNMT had decreasing error rates (fewer GO omissions compared to treated recent-onset patients. fMRI analyses confirmed greater activation of the AG during CPT in chronic patients after HNMT treatment compared to treated

  20. Heidelberg Neuro-Music Therapy Restores Attention-Related Activity in the Angular Gyrus in Chronic Tinnitus Patients.

    Science.gov (United States)

    Krick, Christoph M; Argstatter, Heike; Grapp, Miriam; Plinkert, Peter K; Reith, Wolfgang

    2017-01-01

    Background: Tinnitus is the perception of a phantom sound without external acoustic stimulation. Recent tinnitus research suggests a relationship between attention processes and tinnitus-related distress. It has been found that too much focus on tinnitus comes at the expense of the visual domain. The angular gyrus (AG) seems to play a crucial role in switching attention to the most salient stimulus. This study aims to evaluate the involvement of the AG during visual attention tasks in tinnitus sufferers treated with Heidelberg Neuro-Music Therapy (HNMT), an intervention that has been shown to reduce tinnitus-related distress. Methods: Thirty-three patients with chronic tinnitus, 45 patients with recent-onset tinnitus, and 35 healthy controls were tested. A fraction of these (21/21/22) were treated with the "compact" version of the HNMT lasting 1 week with intense treatments, while non-treated participants were included as passive controls. Visual attention was evaluated during functional Magnet-Resonance Imaging (fMRI) by a visual Continous Performance Task (CPT) using letter-based alarm cues ("O" and "X") appearing in a sequence of neutral letters, "A" through "H." Participants were instructed to respond via button press only if the letter "O" was followed by the letter "X" (GO condition), but not to respond if a neutral letter appeared instead (NOGO condition). All participants underwent two fMRI sessions, before and after a 1-week study period. Results: The CPT results revealed a relationship between error rates and tinnitus duration at baseline whereby the occurrence of erroneous "GO omissions" and the reaction time increased with tinnitus duration. Patients with chronic tinnitus who were treated with HNMT had decreasing error rates (fewer GO omissions) compared to treated recent-onset patients. fMRI analyses confirmed greater activation of the AG during CPT in chronic patients after HNMT treatment compared to treated recent-onset patients. Conclusions: Our

  1. Posterior cortical atrophy.

    Science.gov (United States)

    Zakzanis, K K; Boulos, M I

    2001-11-01

    The term posterior cortical atrophy (PCA) was introduced in 1988 to describe five patients with fairly homogeneous, but otherwise unclassified, symptoms. These patients showed signs of a slowly progressive dementia bearing behavioral and physiologic similarities to Alzheimer's disease, but with notable distinctions. Specifically, PCA is characterized by an early onset of visual agnosia, followed by some or all components of Balint's syndrome, Gerstmann's syndrome, and transcortical sensory aphasia. In this review, the history, epidemiology, pathophysiology, neurobehavioral aspects, assessment (including neurologic and neuropsychologic), differential diagnosis, and treatment recommendations for this disorder are reviewed. As originally defined, PCA appears to be a clinically homogeneous syndrome. The cluster of symptoms that are common to virtually all examined cases evidences this. Although the behavioral and cognitive properties of the disorder are well established, many aspects of PCA remain unclear. Specifically, available research and understanding of PCA epidemiology and treatment are highly inadequate. In fact, the majority of such information regarding PCA is derived from studies of Alzheimer's disease. To a lesser extent, Pick's disease and Creutzfeldt-Jakob disease research have also provided insight into the underpinnings of PCA. Until PCA is categorically defined as a variant or subgroup of these other neurodegenerative disorders, however, such derivations are merely speculations.

  2. Decline of prefrontal cortical-mediated executive functions but attenuated delay discounting in aged Fischer 344 × brown Norway hybrid rats.

    Science.gov (United States)

    Hernandez, Caesar M; Vetere, Lauren M; Orsini, Caitlin A; McQuail, Joseph A; Maurer, Andrew P; Burke, Sara N; Setlow, Barry; Bizon, Jennifer L

    2017-12-01

    Despite the fact that prefrontal cortex (PFC) function declines with age, aged individuals generally show an enhanced ability to delay gratification, as evident by less discounting of delayed rewards in intertemporal choice tasks. The present study was designed to evaluate relationships between 2 aspects of PFC-dependent cognition (working memory and cognitive flexibility) and intertemporal choice in young (6 months) and aged (24 months) Fischer 344 × brown Norway F1 hybrid rats. Rats were also evaluated for motivation to earn rewards using a progressive ratio task. As previously reported, aged rats showed attenuated discounting of delayed rewards, impaired working memory, and impaired cognitive flexibility compared with young. Among aged rats, greater choice of delayed reward was associated with preserved working memory, impaired cognitive flexibility, and less motivation to work for food. These relationships suggest that age-related changes in PFC and incentive motivation contribute to variance in intertemporal choice within the aged population. Cognitive impairments mediated by PFC are unlikely, however, to fully account for the enhanced ability to delay gratification that accompanies aging. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Neuronal correlates to consciousness. The "Hall of Mirrors" metaphor describing consciousness as an epiphenomenon of multiple dynamic mosaics of cortical functional modules.

    Science.gov (United States)

    Agnati, Luigi Francesco; Guidolin, Diego; Cortelli, Pietro; Genedani, Susanna; Cela-Conde, Camilo; Fuxe, Kjell

    2012-10-02

    Humans share the common intuition of a self that has access to an inner 'theater of mind' (Baars, 2003). The problem is how this internal theater is formed. Moving from Cook's view (Cook, 2008), we propose that the 'sentience' present in single excitable cells is integrated into units of neurons and glial cells transiently assembled into "functional modules" (FMs) organized as systems of encased networks (from cell networks to molecular networks). In line with Hebb's proposal of 'cell assemblies', FMs can be linked to form higher-order mosaics by means of reverberating circuits. Brain-level subjective awareness results from the binding phenomenon that coordinates several FM mosaics. Thus, consciousness may be thought as the global result of integrative processes taking place at different levels of miniaturization in plastic mosaics. On the basis of these neurobiological data and speculations and of the evidence of 'mirror neurons' the 'Hall of Mirrors' is proposed as a significant metaphor of consciousness. This article is part of a Special Issue entitled: Brain Integration. Copyright © 2011 Elsevier B.V. All rights reserved.

  4. Classification of Cortical Brain Malformations

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2008-03-01

    Full Text Available Clinical, radiological, and genetic classifications of 113 cases of malformations of cortical development (MCD were evaluated at the Erasmus Medical Center-Sophia Children's Hospital, Rotterdam, the Netherlands.

  5. Disrupted modular organization of resting-state cortical functional connectivity in U.S. military personnel following concussive ‘mild’ blast-related traumatic brain injury†

    Science.gov (United States)

    Han, Kihwan; Mac Donald, Christine L.; Johnson, Ann M.; Barnes, Yolanda; Wierzechowski, Linda; Zonies, David; Oh, John; Flaherty, Stephen; Fang, Raymond; Raichle, Marcus E.; Brody, David L.

    2013-01-01

    Blast-related traumatic brain injury (TBI) has been one of the “signature injuries” of the wars in Iraq and Afghanistan. However, neuroimaging studies in concussive ‘mild’ blast-related TBI have been challenging due to the absence of abnormalities in computed tomography or conventional magnetic resonance imaging (MRI) and the heterogeneity of the blast-related injury mechanisms. The goal of this study was to address these challenges utilizing single-subject, module-based graph theoretic analysis of resting-state functional MRI (fMRI) data. We acquired 20 minutes of resting-state fMRI in 63 U.S. military personnel clinically diagnosed with concussive blast-related TBI and 21 U.S. military controls who had blast exposures but no diagnosis of TBI. All subjects underwent an initial scan within 90 days post-injury and 65 subjects underwent a follow-up scan 6 to 12 months later. A second independent cohort of 40 U.S. military personnel with concussive blast-related TBI patients served as a validation dataset. The second independent cohort underwent an initial scan within 30 days post-injury. 75% of scans were of good quality, with exclusions primarily due to excessive subject motion. Network analysis of the subset of these subjects in the first cohort with good quality scans revealed spatially localized reductions in participation coefficient, a measure of between-module connectivity, in the TBI patients relative to the controls at the time of the initial scan. These group differences were less prominent on the follow-up scans. The 15 brain areas with the most prominent reductions in participation coefficient were next used as regions of interest (ROIs) for single-subject analyses. In the first TBI cohort, more subjects than would be expected by chance (27/47 versus 2/47 expected, p single-subject, multivariate analysis by probabilistic principal component analysis of the between-module connectivity in the 15 identified ROIs, showed that 31/47 subjects in the

  6. Disrupted modular organization of resting-state cortical functional connectivity in U.S. military personnel following concussive 'mild' blast-related traumatic brain injury.

    Science.gov (United States)

    Han, Kihwan; Mac Donald, Christine L; Johnson, Ann M; Barnes, Yolanda; Wierzechowski, Linda; Zonies, David; Oh, John; Flaherty, Stephen; Fang, Raymond; Raichle, Marcus E; Brody, David L

    2014-01-01

    Blast-related traumatic brain injury (TBI) has been one of the "signature injuries" of the wars in Iraq and Afghanistan. However, neuroimaging studies in concussive 'mild' blast-related TBI have been challenging due to the absence of abnormalities in computed tomography or conventional magnetic resonance imaging (MRI) and the heterogeneity of the blast-related injury mechanisms. The goal of this study was to address these challenges utilizing single-subject, module-based graph theoretic analysis of resting-state functional MRI (fMRI) data. We acquired 20min of resting-state fMRI in 63 U.S. military personnel clinically diagnosed with concussive blast-related TBI and 21 U.S. military controls who had blast exposures but no diagnosis of TBI. All subjects underwent an initial scan within 90days post-injury and 65 subjects underwent a follow-up scan 6 to 12months later. A second independent cohort of 40 U.S. military personnel with concussive blast-related TBI served as a validation dataset. The second independent cohort underwent an initial scan within 30days post-injury. 75% of the scans were of good quality, with exclusions primarily due to excessive subject motion. Network analysis of the subset of these subjects in the first cohort with good quality scans revealed spatially localized reductions in the participation coefficient, a measure of between-module connectivity, in the TBI patients relative to the controls at the time of the initial scan. These group differences were less prominent on the follow-up scans. The 15 brain areas with the most prominent reductions in the participation coefficient were next used as regions of interest (ROIs) for single-subject analyses. In the first TBI cohort, more subjects than would be expected by chance (27/47 versus 2/47 expected, p<0.0001) had 3 or more brain regions with abnormally low between-module connectivity relative to the controls on the initial scans. On the follow-up scans, more subjects than expected by chance (5

  7. Hiperostosis cortical infantil

    Directory of Open Access Journals (Sweden)

    Salvador Javier Santos Medina

    2015-04-01

    Full Text Available La enfermedad de Caffey, o hiperostosis cortical infantil, es una rara enfermedad ósea autolimitada, que aparece de preferencia en lactantes con signos inespecíficos sistémicos; el más relevante es la reacción subperióstica e hiperostosis en varios huesos del cuerpo, con predilección en el 75-80 % de los casos por la mandíbula. Su pronóstico es bueno, la mayoría no deja secuelas. El propósito del presente trabajo es describir las características clínicas, presentes en un lactante de cinco meses de edad, atendido en el Hospital Pediátrico Provincial “Mártires de Las Tunas” con este diagnóstico, quien ingresó en el servicio de miscelánea B por una celulitis facial. Presentaba aumento de volumen en la región geniana izquierda, febrícola e inapetencia. Se impuso tratamiento con cefazolina y se egresó a los siete días. Acudió nuevamente con tumefacción blanda y difusa de ambas hemicaras, irritabilidad y fiebre. Se interconsultó con cirugía maxilofacial, se indicaron estudios sanguíneos y radiológicos. Se diagnosticó como enfermedad de Caffey, basado en la edad del niño, tumefacción facial sin signos inflamatorios agudos e hiperostosis en ambas corticales mandibulares a la radiografía AP mandíbula; unido a anemia ligera, leucocitosis y eritrosedimentación acelerada. El paciente se trató sintomáticamente y con antinflamatorios no esteroideos. Esta rara entidad se debe tener presente en casos de niños y lactantes con irritabilidad y fiebre inespecífica

  8. Left Renal Cortical Thickness Measured by Ultrasound Can Predict Early Progression of Chronic Kidney Disease.

    Science.gov (United States)

    Takata, Tomoaki; Koda, Masahiko; Sugihara, Takaaki; Sugihara, Shinobu; Okamoto, Toshiaki; Miyoshi, Kenichi; Hodotsuka, Masanori; Fujise, Yuki; Matono, Tomomitsu; Okano, Junichi; Hosho, Keiko; Iyama, Takuji; Fukui, Takeaki; Fukuda, Satoko; Munemura, Chishio; Isomoto, Hajime

    2016-01-01

    The kidney becomes atrophic in advanced chronic kidney disease, and renal size and parenchymal volume correlate with renal function. However, alterations in renal parenchymal volume have not been adequately studied in terms of the renal cortex and medulla. We investigated the relationship between the changes in the renal cortex and medulla and renal function. Renal ultrasound (US) parameters including renal length, parenchymal thickness, cortical thickness and medullary thickness were assessed in 176 subjects, who were categorized into 4 groups based on the estimated glomerular filtration rate (ml/min/1.73 m2): group 1, ≥ 90; group 2, ≥ 60 but < 90; group 3, ≥ 30 but < 60; and group 4, < 30. Renal US parameters in both kidneys were compared among the 4 groups. We found stepwise associations in renal length, cortical thickness and parenchymal thickness with decreased renal function. Medullary thickness showed no changes among groups 1-3. Multiple linear regression analysis including sex, age and renal US parameters showed that only renal length was an independent predictor of renal function. When analyzed in groups 1-3, cortical thickness was the strongest associated parameter. Lower cortical left/right ratio (left cortical thickness/right cortical thickness) showed a stepwise association with a decrease in renal function. Renal length and cortical thickness measured by US were correlated with renal function. In particular, left cortical thickness could help to detect early changes in renal function. © 2015 S. Karger AG, Basel.

  9. Age-related temporal and parietal cortical thinning in autism spectrum disorders

    OpenAIRE

    Wallace, Gregory L.; Dankner, Nathan; Kenworthy, Lauren; Giedd, Jay N.; Martin, Alex

    2010-01-01

    Studies of head size and brain volume in autism spectrum disorders have suggested that early cortical overgrowth may be followed by prematurely arrested growth. However, the few investigations quantifying cortical thickness have yielded inconsistent results, probably due to variable ages and/or small sample sizes. We assessed differences in cortical thickness between high-functioning adolescent and young adult males with autism spectrum disorders (n = 41) and matched typically developing male...

  10. Response variability in balanced cortical networks

    DEFF Research Database (Denmark)

    Lerchner, Alexander; Ursta, C.; Hertz, J.

    2006-01-01

    We study the spike statistics of neurons in a network with dynamically balanced excitation and inhibition. Our model, intended to represent a generic cortical column, comprises randomly connected excitatory and inhibitory leaky integrate-and-fire neurons, driven by excitatory input from an external...... population. The high connectivity permits a mean field description in which synaptic currents can be treated as gaussian noise, the mean and autocorrelation function of which are calculated self-consistently from the firing statistics of single model neurons. Within this description, a wide range of Fano...

  11. Cortical cartography reveals political and physical maps.

    Science.gov (United States)

    Loring, David W; Gaillard, William Davis; Bookheimer, Susan Y; Meador, Kimford J; Ojemann, Jeffrey G

    2014-05-01

    Advances in functional imaging have provided noninvasive techniques to probe brain organization of multiple constructs including language and memory. Because of high overall rates of agreements with older techniques, including Wada testing and cortical stimulation mapping (CSM), some have proposed that those approaches should be largely abandoned because of their invasiveness, and replaced with noninvasive functional imaging methods. High overall agreement, however, is based largely on concordant language lateralization in series dominated by cases of typical cerebral dominance. Advocating a universal switch from Wada testing and cortical stimulation mapping to functional magnetic resonance imaging (fMRI) or magnetoencephalography (MEG) ignores the differences in specific expertise across epilepsy centers, many of which often have greater skill with one approach rather than the other, and that Wada, CSM, fMRI, and MEG protocols vary across institutions resulting in different outcomes and reliability. Specific patient characteristics also affect whether Wada or CSM might influence surgical management, making it difficult to accept broad recommendations against currently useful clinical tools. Although the development of noninvasive techniques has diminished the frequency of more invasive approaches, advocating their use to replace Wada testing and CSM across all epilepsy surgery programs without consideration of the different skills, protocols, and expertise at any given center site is ill-advised. Wiley Periodicals, Inc. © 2014 International League Against Epilepsy.

  12. Ephaptic coupling in cortical neurons

    Directory of Open Access Journals (Sweden)

    Costas Anastassiou

    2014-03-01

    Full Text Available The electrochemical processes that underlie neural function manifest themselves in ceaseless spatial and temporal fluctuations in the extracellular electric field. The local field potential (LFP, used to study neural interactions during various brain states, is regarded as an epiphenomenon of coordinated neural activity. Yet the extracellular field activity feeds back onto the electrical potential across the neuronal membrane via ephaptic coupling (Jefferys et al, Physiol Rev, 1995. The extent to which such ephaptic coupling alters the functioning of individual neurons and neural assemblies under physiological conditions has remained largely speculative despite recent advances (Ozen et al, JNeurosci, 2010; Fröhlich & McCormick, Neuron, 2010, Anastassiou et al, JNeurosci, 2010. To address this question we use a 12-pipette setup that allows independent positioning of each pipette under visual control with μm accuracy, with the flexibility of using an arbitrary number of these as patching, extracellularly stimulating or extracellular recording pipettes only a few μm away from the cell body of patched neurons (Anastassiou et al, Nat Neurosci, 2011. We stimulated in rat somatosensory cortical slices a variety of layer 5 neural types and recorded inside and outside their cell bodies while pharmacologically silencing synaptic transmission. Pyramidal cells couple to the extracellular field distinctly different from interneurons. Ephaptic coupling strength depends both on the field strength (as measured at the neuron soma as well as the spike-history of neurons. In particular, we find that ephaptic coupling strength depends both on the field strength (as measured at the cell body as well as the spike-history of neurons. How do such effects manifest themselves in vivo? We address this question through detailed large-scale simulations from thousands of biophysically realistic and interconnected neurons (Reimann, Anastassiou et al, Neuron, 2013 emulating

  13. Glycine Receptor α2 Subunit Activation Promotes Cortical Interneuron Migration

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    Ariel Avila

    2013-08-01

    Full Text Available Glycine receptors (GlyRs are detected in the developing CNS before synaptogenesis, but their function remains elusive. This study demonstrates that functional GlyRs are expressed by embryonic cortical interneurons in vivo. Furthermore, genetic disruption of these receptors leads to interneuron migration defects. We discovered that extrasynaptic activation of GlyRs containing the α2 subunit in cortical interneurons by endogenous glycine activates voltage-gated calcium channels and promotes calcium influx, which further modulates actomyosin contractility to fine-tune nuclear translocation during migration. Taken together, our data highlight the molecular events triggered by GlyR α2 activation that control cortical tangential migration during embryogenesis.

  14. Impact of prenatal environmental stress on cortical development

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    Seiji eIshii

    2015-05-01

    Full Text Available Prenatal exposure of the developing brain to various types of environmental stress increases susceptibility to neuropsychiatric disorders such as autism, attention deficit hyperactivity disorder and schizophrenia. Given that even subtle perturbations by prenatal environmental stress in the cerebral cortex impair the cognitive and memory functions, this review focuses on underlying molecular mechanisms of pathological cortical development. We especially highlight recent works that utilized animal exposure models, human specimens or/and induced Pluripotent Stem (iPS cells to demonstrate: 1. molecular mechanisms shared by various types of environmental stressors, 2. the mechanisms by which the affected extracortical tissues indirectly impact the cortical development and function, and 3. interaction between prenatal environmental stress and the genetic predisposition of neuropsychiatric disorders. Finally, we discuss current challenges for achieving a comprehensive understanding of the role of environmentally disturbed molecular expressions in cortical maldevelopment, knowledge of which may eventually facilitate discovery of interventions for prenatal environment-linked neuropsychiatric disorders.

  15. Impact of prenatal environmental stress on cortical development.

    Science.gov (United States)

    Ishii, Seiji; Hashimoto-Torii, Kazue

    2015-01-01

    Prenatal exposure of the developing brain to various types of environmental stress increases susceptibility to neuropsychiatric disorders such as autism, attention deficit hyperactivity disorder and schizophrenia. Given that even subtle perturbations by prenatal environmental stress in the cerebral cortex impair the cognitive and memory functions, this review focuses on underlying molecular mechanisms of pathological cortical development. We especially highlight recent works that utilized animal exposure models, human specimens or/and induced Pluripotent Stem (iPS) cells to demonstrate: (1) molecular mechanisms shared by various types of environmental stressors, (2) the mechanisms by which the affected extracortical tissues indirectly impact the cortical development and function, and (3) interaction between prenatal environmental stress and the genetic predisposition of neuropsychiatric disorders. Finally, we discuss current challenges for achieving a comprehensive understanding of the role of environmentally disturbed molecular expressions in cortical maldevelopment, knowledge of which may eventually facilitate discovery of interventions for prenatal environment-linked neuropsychiatric disorders.

  16. Specialization of Binaural Responses in Ventral Auditory Cortices

    Science.gov (United States)

    Higgins, Nathan C.; Storace, Douglas A.; Escabí, Monty A.

    2010-01-01

    Accurate orientation to sound under challenging conditions requires auditory cortex, but it is unclear how spatial attributes of the auditory scene are represented at this level. Current organization schemes follow a functional division whereby dorsal and ventral auditory cortices specialize to encode spatial and object features of sound source, respectively. However, few studies have examined spatial cue sensitivities in ventral cortices to support or reject such schemes. Here Fourier optical imaging was used to quantify best frequency responses and corresponding gradient organization in primary (A1), anterior, posterior, ventral (VAF), and suprarhinal (SRAF) auditory fields of the rat. Spike rate sensitivities to binaural interaural level difference (ILD) and average binaural level cues were probed in A1 and two ventral cortices, VAF and SRAF. Continuous distributions of best ILDs and ILD tuning metrics were observed in all cortices, suggesting this horizontal position cue is well covered. VAF and caudal SRAF in the right cerebral hemisphere responded maximally to midline horizontal position cues, whereas A1 and rostral SRAF responded maximally to ILD cues favoring more eccentric positions in the contralateral sound hemifield. SRAF had the highest incidence of binaural facilitation for ILD cues corresponding to midline positions, supporting current theories that auditory cortices have specialized and hierarchical functional organization. PMID:20980610

  17. A mechanism for the cortical computation of hierarchical linguistic structure.

    Directory of Open Access Journals (Sweden)

    Andrea E Martin

    2017-03-01

    Full Text Available Biological systems often detect species-specific signals in the environment. In humans, speech and language are species-specific signals of fundamental biological importance. To detect the linguistic signal, human brains must form hierarchical representations from a sequence of perceptual inputs distributed in time. What mechanism underlies this ability? One hypothesis is that the brain repurposed an available neurobiological mechanism when hierarchical linguistic representation became an efficient solution to a computational problem posed to the organism. Under such an account, a single mechanism must have the capacity to perform multiple, functionally related computations, e.g., detect the linguistic signal and perform other cognitive functions, while, ideally, oscillating like the human brain. We show that a computational model of analogy, built for an entirely different purpose-learning relational reasoning-processes sentences, represents their meaning, and, crucially, exhibits oscillatory activation patterns resembling cortical signals elicited by the same stimuli. Such redundancy in the cortical and machine signals is indicative of formal and mechanistic alignment between representational structure building and "cortical" oscillations. By inductive inference, this synergy suggests that the cortical signal reflects structure generation, just as the machine signal does. A single mechanism-using time to encode information across a layered network-generates the kind of (decompositional representational hierarchy that is crucial for human language and offers a mechanistic linking hypothesis between linguistic representation and cortical computation.

  18. Muscle synergy patterns as physiological markers of motor cortical damage

    Science.gov (United States)

    Cheung, Vincent C. K.; Turolla, Andrea; Agostini, Michela; Silvoni, Stefano; Bennis, Caoimhe; Kasi, Patrick; Paganoni, Sabrina; Bonato, Paolo; Bizzi, Emilio

    2012-01-01

    The experimental findings herein reported are aimed at gaining a perspective on the complex neural events that follow lesions of the motor cortical areas. Cortical damage, whether by trauma or stroke, interferes with the flow of descending signals to the modular interneuronal structures of the spinal cord. These spinal modules subserve normal motor behaviors by activating groups of muscles as individual units (muscle synergies). Damage to the motor cortical areas disrupts the orchestration of the modules, resulting in abnormal movements. To gain insights into this complex process, we recorded myoelectric signals from multiple upper-limb muscles in subjects with cortical lesions. We used a factorization algorithm to identify the muscle synergies. Our factorization analysis revealed, in a quantitative way, three distinct patterns of muscle coordination—including preservation, merging, and fractionation of muscle synergies—that reflect the multiple neural responses that occur after cortical damage. These patterns varied as a function of both the severity of functional impairment and the temporal distance from stroke onset. We think these muscle-synergy patterns can be used as physiological markers of the status of any patient with stroke or trauma, thereby guiding the development of different rehabilitation approaches, as well as future physiological experiments for a further understanding of postinjury mechanisms of motor control and recovery. PMID:22908288

  19. Paroxysmal kinesigenic dyskinesia : Cortical or non-cortical origin

    NARCIS (Netherlands)

    van Strien, Teun W.; van Rootselaar, Anne-Fleur; Hilgevoord, Anthony A. J.; Linssen, Wim H. J. P.; Groffen, Alexander J. A.; Tijssen, Marina A. J.

    Paroxysmal kinesigenic dyskinesia (PKD) is characterized by involuntary dystonia and/or chorea triggered by a sudden movement. Cases are usually familial with an autosomal dominant inheritance. Hypotheses regarding the pathogenesis of PKD focus on the controversy whether PKD has a cortical or

  20. Development and aging of cortical thickness correspond to genetic organization patterns.

    Science.gov (United States)

    Fjell, Anders M; Grydeland, Håkon; Krogsrud, Stine K; Amlien, Inge; Rohani, Darius A; Ferschmann, Lia; Storsve, Andreas B; Tamnes, Christian K; Sala-Llonch, Roser; Due-Tønnessen, Paulina; Bjørnerud, Atle; Sølsnes, Anne Elisabeth; Håberg, Asta K; Skranes, Jon; Bartsch, Hauke; Chen, Chi-Hua; Thompson, Wesley K; Panizzon, Matthew S; Kremen, William S; Dale, Anders M; Walhovd, Kristine B

    2015-12-15

    There is a growing realization that early life influences have lasting impact on brain function and structure. Recent research has demonstrated that genetic relationships in adults can be used to parcellate the cortex into regions of maximal shared genetic influence, and a major hypothesis is that genetically programmed neurodevelopmental events cause a lasting impact on the organization of the cerebral cortex observable decades later. Here we tested how developmental and lifespan changes in cortical thickness fit the underlying genetic organizational principles of cortical thickness in a longitudinal sample of 974 participants between 4.1 and 88.5 y of age with a total of 1,633 scans, including 773 scans from children below 12 y. Genetic clustering of cortical thickness was based on an independent dataset of 406 adult twins. Developmental and adult age-related changes in cortical thickness followed closely the genetic organization of the cerebral cortex, with change rates varying as a function of genetic similarity between regions. Cortical regions with overlapping genetic architecture showed correlated developmental and adult age change trajectories and vice versa for regions with low genetic overlap. Thus, effects of genes on regional variations in cortical thickness in middle age can be traced to regional differences in neurodevelopmental change rates and extrapolated to further adult aging-related cortical thinning. This finding suggests that genetic factors contribute to cortical changes through life and calls for a lifespan perspective in research aimed at identifying the genetic and environmental determinants of cortical development and aging.

  1. A Laminar Organization for Selective Cortico-Cortical Communication

    Directory of Open Access Journals (Sweden)

    Rinaldo D. D’Souza

    2017-08-01

    Full Text Available The neocortex is central to mammalian cognitive ability, playing critical roles in sensory perception, motor skills and executive function. This thin, layered structure comprises distinct, functionally specialized areas that communicate with each other through the axons of pyramidal neurons. For the hundreds of such cortico-cortical pathways to underlie diverse functions, their cellular and synaptic architectures must differ so that they result in distinct computations at the target projection neurons. In what ways do these pathways differ? By originating and terminating in different laminae, and by selectively targeting specific populations of excitatory and inhibitory neurons, these “interareal” pathways can differentially control the timing and strength of synaptic inputs onto individual neurons, resulting in layer-specific computations. Due to the rapid development in transgenic techniques, the mouse has emerged as a powerful mammalian model for understanding the rules by which cortical circuits organize and function. Here we review our understanding of how cortical lamination constrains long-range communication in the mammalian brain, with an emphasis on the mouse visual cortical network. We discuss the laminar architecture underlying interareal communication, the role of neocortical layers in organizing the balance of excitatory and inhibitory actions, and highlight the structure and function of layer 1 in mouse visual cortex.

  2. Interhemispheric Connectivity Characterizes Cortical Reorganization in Motor-Related Networks After Cerebellar Lesions.

    Science.gov (United States)

    De Vico Fallani, Fabrizio; Clausi, Silvia; Leggio, Maria; Chavez, Mario; Valencia, Miguel; Maglione, Anton Giulio; Babiloni, Fabio; Cincotti, Febo; Mattia, Donatella; Molinari, Marco

    2017-04-01

    Although cerebellar-cortical interactions have been studied extensively in animal models and humans using modern neuroimaging techniques, the effects of cerebellar stroke and focal lesions on cerebral cortical processing remain unknown. In the present study, we analyzed the large-scale functional connectivity at the cortical level by combining high-density electroencephalography (EEG) and source imaging techniques to evaluate and quantify the compensatory reorganization of brain networks after cerebellar damage. The experimental protocol comprised a repetitive finger extension task by 10 patients with unilateral focal cerebellar lesions and 10 matched healthy controls. A graph theoretical approach was used to investigate the functional reorganization of cortical networks. Our patients, compared with controls, exhibited significant differences at global and local topological level of their brain networks. An abnormal rise in small-world network efficiency was observed in the gamma band (30-40 Hz) during execution of the task, paralleled by increased long-range connectivity between cortical hemispheres. Our findings show that a pervasive reorganization of the brain network is associated with cerebellar focal damage and support the idea that the cerebellum boosts or refines cortical functions. Clinically, these results suggest that cortical changes after cerebellar damage are achieved through an increase in the interactions between remote cortical areas and that rehabilitation should aim to reshape functional activation patterns. Future studies should determine whether these hypotheses are limited to motor tasks or if they also apply to cerebro-cerebellar dysfunction in general.

  3. Cortical morphometry and IQ in VLBW children without cerebral palsy born in 2003–2007

    Directory of Open Access Journals (Sweden)

    Anne Elisabeth Sølsnes

    2015-01-01

    We conclude that cortical deviations are evident in childhood even in VLBW children born in 2003–2007 who have received state of the art medical treatment in the perinatal period and who did not present with focal brain injuries on neonatal ultrasonography. The cortical deviations were associated with reduced cognitive functioning.

  4. Cortical control of normal gait and precision stepping: an fNIRS study

    NARCIS (Netherlands)

    Koenraadt, K.L.M.; Roelofsen, E.G.J.; Duysens, J.E.J.; Keijsers, N.L.W.

    2014-01-01

    Recently, real time imaging of the cortical control of gait became possible with functional near-infrared spectroscopy (fNIRS). So far, little is known about the activations of various cortical areas in more complex forms of gait, such as precision stepping. From previous work on animals and humans

  5. Inferring Cortical Variability from Local Field Potentials.

    Science.gov (United States)

    Cui, Yuwei; Liu, Liu D; McFarland, James M; Pack, Christopher C; Butts, Daniel A

    2016-04-06

    The responses of sensory neurons can be quite different to repeated presentations of the same stimulus. Here, we demonstrate a direct link between the trial-to-trial variability of cortical neuron responses and network activity that is reflected in local field potentials (LFPs). Spikes and LFPs were recorded with a multielectrode array from the middle temporal (MT) area of the visual cortex of macaques during the presentation of continuous optic flow stimuli. A maximum likelihood-based modeling framework was used to predict single-neuron spiking responses using the stimulus, the LFPs, and the activity of other recorded neurons. MT neuron responses were strongly linked to gamma oscillations (maximum at 40 Hz) as well as to lower-frequency delta oscillations (1-4 Hz), with consistent phase preferences across neurons. The predicted modulation associated with the LFP was largely complementary to that driven by visual stimulation, as well as the activity of other neurons, and accounted for nearly half of the trial-to-trial variability in the spiking responses. Moreover, the LFP model predictions accurately captured the temporal structure of noise correlations between pairs of simultaneously recorded neurons, and explained the variation in correlation magnitudes observed across the population. These results therefore identify signatures of network activity related to the variability of cortical neuron responses, and suggest their central role in sensory cortical function. The function of sensory neurons is nearly always cast in terms of representing sensory stimuli. However, recordings from visual cortex in awake animals show that a large fraction of neural activity is not predictable from the stimulus. We show that this variability is predictable given the simultaneously recorded measures of network activity, local field potentials. A model that combines elements of these signals with the stimulus processing of the neuron can predict neural responses dramatically better

  6. Cortical deafness in multiple sclerosis

    OpenAIRE

    Tabira, T; Tsuji, S; Nagashima, T.; Nakajima, T.; Kuroiwa, Y

    1981-01-01

    Cortical deafness in a patient with multiple sclerosis is reported. Complete recovery from total deafness was seen following stages of auditory agnosia and pure word deafness. The otological and neurophysiological studies suggested lesions in subcortical white matter. This report stresses the rarity of the condition, its subcortical origin and good prognosis.

  7. Cortical Basis for Dichotic Pitch Perception in Developmental Dyslexia

    Science.gov (United States)

    Partanen, Marita; Fitzpatrick, Kevin; Madler, Burkhard; Edgell, Dorothy; Bjornson, Bruce; Giaschi, Deborah E.

    2012-01-01

    The current study examined auditory processing deficits in dyslexia using a dichotic pitch stimulus and functional MRI. Cortical activation by the dichotic pitch task occurred in bilateral Heschl's gyri, right planum temporale, and right superior temporal sulcus. Adolescents with dyslexia, relative to age-matched controls, illustrated greater…

  8. Influence of spontaneous rhythm on movement-related cortical potential

    DEFF Research Database (Denmark)

    Yao, Lin; Chen, Mei Lin; Sheng, Xinjun

    2017-01-01

    We have recently developed an associative Brain-Computer Interface (BCI) for neuromodulation in chronic and acute stroke patients that leads to functional improvements. The control signal is the movement related cortical potential (MRCP) that develops prior to movement execution. The MRCP increases...

  9. Coexistence of tonic firing and bursting in cortical neurons

    Science.gov (United States)

    Fröhlich, Flavio; Bazhenov, Maxim

    2006-09-01

    Sustained neuronal activity can be broadly classified as either tonic firing or bursting. These two major patterns of neuronal oscillations are state dependent and may coexist. The dynamics and intracellular mechanisms of transitions between tonic firing and bursting in cortical networks remain poorly understood. Here we describe a detailed two-compartment conductance-based cortical neuron model which exhibits bistability with hysteresis between tonic firing and bursting for elevated extracellular potassium concentration. The study explains the ionic and dynamical mechanisms of burst generation and reveals the conditions underlying coexistence of two different oscillatory modes as a function of neuronal excitability.

  10. Tactile thermal oral stimulation increases the cortical representation of swallowing

    Directory of Open Access Journals (Sweden)

    Suntrup Sonja

    2009-06-01

    Full Text Available Abstract Background Dysphagia is a leading complication in stroke patients causing aspiration pneumonia, malnutrition and increased mortality. Current strategies of swallowing therapy involve on the one hand modification of eating behaviour or swallowing technique and on the other hand facilitation of swallowing with the use of pharyngeal sensory stimulation. Thermal tactile oral stimulation (TTOS is an established method to treat patients with neurogenic dysphagia especially if caused by sensory deficits. Little is known about the possible mechanisms by which this interventional therapy may work. We employed whole-head MEG to study changes in cortical activation during self-paced volitional swallowing in fifteen healthy subjects with and without TTOS. Data were analyzed by means of synthetic aperture magnetometry (SAM and the group analysis of individual SAM data was performed using a permutation test. Results Compared to the normal swallowing task a significantly increased bilateral cortical activation was seen after oropharyngeal stimulation. Analysis of the chronological changes during swallowing suggests facilitation of both the oral and the pharyngeal phase of deglutition. Conclusion In the present study functional cortical changes elicited by oral sensory stimulation could be demonstrated. We suggest that these results reflect short-term cortical plasticity of sensory swallowing areas. These findings facilitate our understanding of the role of cortical reorganization in dysphagia treatment and recovery.

  11. Tactile thermal oral stimulation increases the cortical representation of swallowing

    Science.gov (United States)

    Teismann, Inga K; Steinsträter, Olaf; Warnecke, Tobias; Suntrup, Sonja; Ringelstein, Erich B; Pantev, Christo; Dziewas, Rainer

    2009-01-01

    Background Dysphagia is a leading complication in stroke patients causing aspiration pneumonia, malnutrition and increased mortality. Current strategies of swallowing therapy involve on the one hand modification of eating behaviour or swallowing technique and on the other hand facilitation of swallowing with the use of pharyngeal sensory stimulation. Thermal tactile oral stimulation (TTOS) is an established method to treat patients with neurogenic dysphagia especially if caused by sensory deficits. Little is known about the possible mechanisms by which this interventional therapy may work. We employed whole-head MEG to study changes in cortical activation during self-paced volitional swallowing in fifteen healthy subjects with and without TTOS. Data were analyzed by means of synthetic aperture magnetometry (SAM) and the group analysis of individual SAM data was performed using a permutation test. Results Compared to the normal swallowing task a significantly increased bilateral cortical activation was seen after oropharyngeal stimulation. Analysis of the chronological changes during swallowing suggests facilitation of both the oral and the pharyngeal phase of deglutition. Conclusion In the present study functional cortical changes elicited by oral sensory stimulation could be demonstrated. We suggest that these results reflect short-term cortical plasticity of sensory swallowing areas. These findings facilitate our understanding of the role of cortical reorganization in dysphagia treatment and recovery. PMID:19566955

  12. Review: Cortical construction in autism spectrum disorder: columns, connectivity and the subplate.

    Science.gov (United States)

    Hutsler, Jeffrey J; Casanova, Manuel F

    2016-02-01

    The cerebral cortex undergoes protracted maturation during human development and exemplifies how biology and environment are inextricably intertwined in the construction of complex neural circuits. Autism spectrum disorders are characterized by a number of pathological changes arising from this developmental process. These include: (i) alterations to columnar structure that have significant implications for the organization of cortical circuits and connectivity; (ii) alterations to synaptic spines on individual cortical units that may underlie specific types of connectional changes; and (iii) alterations within the cortical subplate, a region that plays a role in proper cortical development and in regulating interregional communication in the mature brain. Although the cerebral cortex is not the only structure affected in the disorder, it is a fundamental contributor to the behaviours that characterize autism. These alterations to cortical circuitry likely underlie the behavioural phenotype in autism and contribute to the unique pattern of deficits and strengths that characterize cognitive functioning. Recent findings within the cortical subplate may indicate that alterations to cortical construction begin prenatally, before activity-dependent connections are established, and are in need of further study. A better understanding of cortical development in autism spectrum disorders will draw bridges between the microanatomical computational circuitry and the atypical behaviours that arise when that circuitry is modified. In addition, it will allow us to better exploit the constructional plasticity within the brain to design more targeted interventions that better manage atypical cortical construction and that can be applied very early in postnatal life. © 2015 British Neuropathological Society.

  13. Specificity of cortical synaptic connectivity: emphasis on perspectives gained from quantitative electron microscopy.

    Science.gov (United States)

    White, Edward L

    2002-01-01

    This report traces the historical development of concepts regarding the specificity of synaptic connectivity in the cerebral cortex as viewed primarily from the perspective of electron microscopy. The occurrence of stereotypical patterns of connection (e.g., contrasting synaptic patterns on the surfaces of spiny vs. non-spiny neurons, the general consistency with which axonal pathways impinge on and originate within specific cortical areas and layers, triadic synaptic relationships) implies that cortical connectivity is highly structured. The high degree of order characterizing many aspects of cortical organization is mirrored by an equally ordered arrangement of synaptic connections between specific types of neurons. This observation is based on quantitative electron microscopic studies of synapses between identified neurons and from the results of correlative anatomical/electrophysiological investigations. The recognition of recurring synaptic patterns and responses between specific neurons has generated increased support for the notion of specificity of synaptic connections at the expense of randomness, but the role of specificity in cortical function is an unresolved question. At the core of cortical processing lie myriad possibilities for computation provided by the wealth of synaptic connections involving each cortical neuron. Specificity, by limiting possibilities for connection, can impose an order on synaptic interactions even as processes of dynamic selection or synaptic remodeling ensure the constant formation and dissolution of cortical circuits. These operations make maximal use of the richness of cortical synaptic connections to produce a highly flexible system, irrespective of the degree of randomness or specificity that obtains for cortical wiring at any particular time.

  14. Otx2-PNN Interaction to Regulate Cortical Plasticity

    Directory of Open Access Journals (Sweden)

    Clémence Bernard

    2016-01-01

    Full Text Available The ability of the environment to shape cortical function is at its highest during critical periods of postnatal development. In the visual cortex, critical period onset is triggered by the maturation of parvalbumin inhibitory interneurons, which gradually become surrounded by a specialized glycosaminoglycan-rich extracellular matrix: the perineuronal nets. Among the identified factors regulating cortical plasticity in the visual cortex, extracortical homeoprotein Otx2 is transferred specifically into parvalbumin interneurons and this transfer regulates both the onset and the closure of the critical period of plasticity for binocular vision. Here, we review the interaction between the complex sugars of the perineuronal nets and homeoprotein Otx2 and how this interaction regulates cortical plasticity during critical period and in adulthood.

  15. Malformations of cortical development: current concepts and advanced neuroimaging review

    Directory of Open Access Journals (Sweden)

    Celi Santos Andrade

    2011-02-01

    Full Text Available Malformations of cortical development (MCD result from disruptions in the complex process of the human brain cortex formation and are highly associated to severe epilepsy, neurodevelopmental delay and motor dysfunction. Nowadays, magnetic resonance imaging (MRI is the cornerstone of the work-up of patients with epilepsy and modern advanced imaging techniques have improved not only our ability to detect and characterize cortical malformations, but also in identifying associated functional abnormalities that are far beyond the structural visualized lesions. Herein, we address the most currently used classifications of MCD and make a concise review of the embryological process of cortical development. Our main goal is to summarize recent advances and new trends in diagnostic imaging techniques concerning MCD. Thereafter, follows a brief discussion of specific disorders and their radiological features.

  16. Magnetoencephalography from signals to dynamic cortical networks

    CERN Document Server

    Aine, Cheryl

    2014-01-01

    "Magnetoencephalography (MEG) provides a time-accurate view into human brain function. The concerted action of neurons generates minute magnetic fields that can be detected---totally noninvasively---by sensitive multichannel magnetometers. The obtained millisecond accuracycomplements information obtained by other modern brain-imaging tools. Accurate timing is quintessential in normal brain function, often distorted in brain disorders. The noninvasiveness and time-sensitivityof MEG are great assets to developmental studies, as well. This multiauthored book covers an ambitiously wide range of MEG research from introductory to advanced level, from sensors to signals, and from focal sources to the dynamics of cortical networks. Written by active practioners of this multidisciplinary field, the book contains tutorials for newcomers and chapters of new challenging methods and emerging technologies to advanced MEG users. The reader will obtain a firm grasp of the possibilities of MEG in the study of audition, vision...

  17. Age-dependent cortical thinning of peripheral visual field representations in primary visual cortex

    Directory of Open Access Journals (Sweden)

    Joseph Caleb Griffis

    2016-10-01

    Full Text Available The cerebral cortex changes throughout the lifespan, and the cortical grey matter in many brain regions becomes thinner with advancing age. Effects of aging on cortical thickness have been observed in many brain regions, including areas involved in basic perceptual functions such as processing visual inputs. An important property of early visual cortices is their topographic organization – the cortical structure of early visual areas forms a topographic map of retinal inputs. Primary visual cortex (V1 is considered to be the most basic cortical area in the visual processing hierarchy, and is topographically organized from posterior (central visual representation to anterior (peripheral visual representation along the calcarine sulcus. Some studies have reported strong age-dependent cortical thinning in portions of V1 that likely correspond to peripheral visual representations, while there is less evidence of substantial cortical thinning in central V1. However, the effect of aging on cortical thickness in V1 as a function of its topography has not been directly investigated. To address this gap in the literature, we estimated the cortical thickness of different eccentricity sectors in V1 using T1-weighted MRI scans acquired from groups of healthy younger and older adults, and then assessed whether between-group differences in V1 cortical thickness depended on cortical eccentricity. These analyses revealed age-dependent cortical thinning specific to peripheral visual field representations in anterior portions of V1, but did not provide evidence for age-dependent cortical thinning in other portions of V1. Additional analyses found similar effects when analyses were restricted to the gyral crown, sulcul depth, and sulcul wall, indicating that these effects are not likely due to differences in gyral/sulcul contributions to our regions of interest. Importantly, this finding indicates that age-dependent changes in cortical structure may differ among

  18. Mapping effective connectivity within cortical networks with diffuse optical tomography.

    Science.gov (United States)

    Hassanpour, Mahlega S; Eggebrecht, Adam T; Peelle, Jonathan E; Culver, Joseph P

    2017-10-01

    Understanding how cortical networks interact in response to task demands is important both for providing insight into the brain's processing architecture and for managing neurological diseases and mental disorders. High-density diffuse optical tomography (HD-DOT) is a neuroimaging technique that offers the significant advantages of having a naturalistic, acoustically controllable environment and being compatible with metal implants, neither of which is possible with functional magnetic resonance imaging. We used HD-DOT to study the effective connectivity and assess the modulatory effects of speech intelligibility and syntactic complexity on functional connections within the cortical speech network. To accomplish this, we extend the use of a generalized psychophysiological interaction (PPI) analysis framework. In particular, we apply PPI methods to event-related HD-DOT recordings of cortical oxyhemoglobin activity during auditory sentence processing. We evaluate multiple approaches for selecting cortical regions of interest and for modeling interactions among these regions. Our results show that using subject-based regions has minimal effect on group-level connectivity maps. We also demonstrate that incorporating an interaction model based on estimated neural activity results in significantly stronger effective connectivity. Taken together our findings support the use of HD-DOT with PPI methods for noninvasively studying task-related modulations of functional connectivity.

  19. Shaken infant syndrome: developmental neuropathology, progressive cortical dysplasia, and epilepsy.

    Science.gov (United States)

    Marín-Padilla, Miguel; Parisi, Joseph E; Armstrong, Dawna L; Sargent, Steve K; Kaplan, James A

    2002-04-01

    This study describes the developmental neuropathology of two infants who survived 7 and 9 years, respectively, an episode of violent shaking (shaken infant syndrome) early in their lives. The shaking injuries include cortical and subcortical contusions, hemorrhages, hypoxic/ischemic and axonal damage, and severe edema. The types, distribution, and resolution of these shaking injuries are detailed by sequential radiographic studies and by pathologic examination at postmortem. Despite their severity and extent, these injuries resolved in a relatively short period of time. By 6 months, the original injuries are repaired and the resultant encephaloclastic encephalopathies (e.g., multicystic encephalomalacia, porencephaly, generalized white matter attenuation, diffuse cortical atrophy, microgyria, ulegyria, and hydrocephalus ex vacuo) are well established. No appreciable pathologic differences are detected when radiographic findings at 6 months of age are compared to postmortem observations. On the other hand, undamaged and/or partially damaged cortical regions survive the original insult and undergo post-injury reorganization that transforms the residual cortex structural and presumably functional organization. Prominent features of this post-injury reorganization include progressive cortical dysplasia with cytoarchitectural disorganization, laminar obliteration, morphologic and functional (synaptic reorganization) transformation of some neurons, preservation of layer 1 intrinsic fibers and Cajal-Retzius cells, and the presence of large (hypertrophic) intrinsic neurons with intense neurofilament immunoreactivity. We propose that this progressive dysplastic process modifies the residual cortex structural and functional organization, influences the child's neurological and psychological maturation, and may play a significant role in the pathogenesis of ensuing neurological and/or psychological sequelae.

  20. Comparative neuropsychology of cortical and subcortical dementia.

    Science.gov (United States)

    Freedman, M; Oscar-Berman, M

    1986-11-01

    The terms "cortical" and "subcortical" dementia are controversial; however, the clinical distinction between them is real. For example, although Alzheimer's and Parkinson's disease (prototypical of cortical and subcortical dementia, respectively) share clinical features, they differ in the presence of aphasia, apraxia, and agnosia in Alzheimer's disease but not in Parkinson's dementia. We review our studies aimed at clarifying the mechanisms underlying the differences between these neurological disorders. Experimental paradigms adopted from animal models were used to study the functional anatomy and neuropsychological characteristics of Alzheimer's and Parkinson's disease. The tasks administered include delayed alternation (DA) and delayed response (DR), which are sensitive to frontal system damage, and tactile discrimination learning (TOL) and reversal (TRL) paradigms sensitive to parietal system damage. Alzheimer's patients were significantly impaired on all tasks whereas Parkinsonians with dementia were impaired only on DR and TRL. Consideration of neuroanatomical and neuropsychological mechanisms involved in DA, DR, TOL, and TRL appears to have sharpened the distinction between Alzheimer's and Parkinson's dementia. Dementia in Alzheimer's disease may involve dorsolateral frontal, orbitofrontal and parietal systems. In contrast, dementia in Parkinson's disease may involve prominent dorsolateral frontal system damage.

  1. Imprinting and recalling cortical ensembles.

    Science.gov (United States)

    Carrillo-Reid, Luis; Yang, Weijian; Bando, Yuki; Peterka, Darcy S; Yuste, Rafael

    2016-08-12

    Neuronal ensembles are coactive groups of neurons that may represent building blocks of cortical circuits. These ensembles could be formed by Hebbian plasticity, whereby synapses between coactive neurons are strengthened. Here we report that repetitive activation with two-photon optogenetics of neuronal populations from ensembles in the visual cortex of awake mice builds neuronal ensembles that recur spontaneously after being imprinted and do not disrupt preexisting ones. Moreover, imprinted ensembles can be recalled by single- cell stimulation and remain coactive on consecutive days. Our results demonstrate the persistent reconfiguration of cortical circuits by two-photon optogenetics into neuronal ensembles that can perform pattern completion. Copyright © 2016, American Association for the Advancement of Science.

  2. mGluR5 in cortical excitatory neurons exerts both cell autonomous and nonautonomous influences on cortical somatosensory circuit formation

    OpenAIRE

    Ballester-Rosado, Carlos J.; Albright, Michael J.; Wu, Chia-Shan; Liao, Chun-Chieh; Zhu, Jie; Xu, Jian; Lee, Li-Jen; Lu, Hui-Chen

    2010-01-01

    Glutamatergic neurotransmission plays important roles in sensory map formation. The absence of the group I metabotropic glutamate receptor 5 (mGluR5) leads to abnormal sensory map formation throughout the mouse somatosensory pathway. To examine the role of cortical mGluR5 expression on barrel map formation, we generated cortex-specific mGluR5 KO mice. Eliminating mGluR5 function solely in cortical excitatory neurons, not only affects the whisker-related organization of cortical neurons (barre...

  3. rab3 mediates cortical granule exocytosis in the sea urchin egg.

    Science.gov (United States)

    Conner, S; Wessel, G M

    1998-11-15

    Egg activation at fertilization in the sea urchin results in the exocytosis of approximately 15,000 cortical granules that are docked at the plasma membrane. Previously, we reported that several integral membrane proteins modeled in the SNARE hypothesis, synaptotagmin, VAMP, and syntaxin, in addition to a small GTPase of the ras superfamily, rab3, were present on cortical granules (Conner, S., Leaf, D., and Wessel, G., Mol. Reprod. Dev. 48, 1-13, 1997). Here we report that rab3 is associated with cortical granules throughout oogenesis, during cortical granule translocation, and while docked at the egg plasma membrane. Following cortical granule exocytosis, however, rab3 reassociates with a different population of vesicles, at least some of which are of endocytic origin. Because of its selective association with cortical granules in eggs and oocytes, we hypothesize that rab3 functions in cortical granule exocytosis. To test this hypothesis, we used a strategy of interfering with rab3 function by peptide competition with its effector domain, a conserved region within specific rab types. We first identified the effector domain sequence in Lytechinus variegatus eggs and find the sequence 94% identical to the effector domain of rab3 in Stronglocentrotus purpuratus. Then, with synthetic peptides to different regions of the rab3 protein, we find that cortical granule exocytosis is inhibited in eggs injected with effector domain peptides, but not with peptides from the hypervariable region or with a scrambled effector peptide. Additionally, effector-peptide-injected eggs injected with IP3 are blocked in their ability to exocytose cortical granules, suggesting that the inhibition is directly on the membrane fusion event and not the result of interference with the signal transduction mechanism leading to calcium release. We interpret these results to mean that rab3 functions in the regulation of cortical granule exocytosis following vesicle docking. Copyright 1998 Academic

  4. Regional Cortical Grey Matter Loss in Parkinson's Disease Without Dementia is Independent from Visual Hallucinations

    NARCIS (Netherlands)

    Meppelink, Anne Marthe; de Jong, Bauke M.; Teune, Laura K.; van Laar, Teus

    In our previous functional magnetic resonance imaging study, Parkinson's disease (PD) patients with visual hallucinations (VH) showed reduced activations in ventral/ lateral visual association cortices preceding image recognition, compared with both PD patients without VH and healthy controls. The

  5. Delayed visual maturation: pupillary responses implicate subcortical and cortical visual systems

    National Research Council Canada - National Science Library

    Cocker, K D; Moseley, M J; Stirling, H F; Fielder, A R

    1998-01-01

    .... The improvement of vision in delayed visual maturation (DVM) occurs around this time, and this has given rise to the suggestion that the condition may have a subcortical basis that resolves with the appearance of cortical function...

  6. Intracranial cortical localization of the human K-complex.

    Science.gov (United States)

    Wennberg, Richard

    2010-08-01

    The K-complex was first identified in human sleep EEG more than 70years ago, but the localization of its intracranial generators is an unresolved issue. In this study, K-complexes recorded using simultaneous scalp and intracranial EEG were analyzed to discover the intracranial distribution of the human K-complex. Stereoelectroencephalographic recordings were performed in six patients with medically-refractory epilepsy. Full 10-20 scalp montages were used and intracranial macroelectrodes sampled medial, lateral and basal frontal and temporal cortices, medial and lateral parietal and occipital cortices, as well as the hippocampus and thalamus. Spontaneous K-complexes were visually identified in stage II sleep and averaged off-line. The intracranial K-complex field was maximal over the anterior and superior aspects of the medial and lateral frontal lobe cortices, consistent with the frontal midline scalp EEG maximum. The frontal maximum surface-negative field was volume conducted as an inverted, positive field posteriorly and inferiorly, the polarity reversing laterally above the inferior temporal region and medially above the cingulate cortex. As suggested by the scalp EEG topography, the intracranial distribution of the human K-complex is maximal over the anterior and superior frontal cortices. K-complex generation appears limited to cortical regions above the inferior temporal sulcus laterally, the cingulate sulcus medially and the parietooccipital junction posteriorly. The human K-complex is produced by synchronous cortical activity that appears maximal intracranially over the superior medial and lateral aspects of the frontal lobes. The cingulate cortex and functionally related mesial temporal structures appear uninvolved in human K-complex generation. Copyright 2010 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  7. Microtubules mediate changes in membrane cortical elasticity during contractile activation.

    Science.gov (United States)

    Al-Rekabi, Zeinab; Haase, Kristina; Pelling, Andrew E

    2014-03-10

    The mechanical properties of living cells are highly regulated by remodeling dynamics of the cytoarchitecture, and are linked to a wide variety of physiological and pathological processes. Microtubules (MT) and actomyosin contractility are both involved in regulating focal adhesion (FA) size and cortical elasticity in living cells. Although several studies have examined the effects of MT depolymerization or actomyosin activation on biological processes, very few have investigated the influence of both on the mechanical properties, FA assembly, and spreading of fibroblast cells. Here, we examine how activation of both processes modulates cortical elasticity as a function of time. Enhancement of contractility (calyculin A treatment) or the depolymerization of MTs (nocodazole treatment) individually caused a time-dependent increase in FA size, decrease in cell height and an increase in cortical elasticity. Surprisingly, sequentially stimulating both processes led to a decrease in cortical elasticity, loss of intact FAs and a concomitant increase in cell height. Our results demonstrate that loss of MTs disables the ability of fibroblast cells to maintain increased contractility and cortical elasticity upon activation of myosin-II. We speculate that in the absence of an intact MT network, a large amount of contractile tension is transmitted directly to FA sites resulting in their disassembly. This implies that tension-mediated FA growth may have an upper bound, beyond which disassembly takes place. The interplay between cytoskeletal remodeling and actomyosin contractility modulates FA size and cell height, leading to dynamic time-dependent changes in the cortical elasticity of fibroblast cells. Crown Copyright © 2014. Published by Elsevier Inc. All rights reserved.

  8. Cortical hyperexcitability and disease spread in amyotrophic lateral sclerosis.

    Science.gov (United States)

    Menon, P; Geevasinga, N; van den Bos, M; Yiannikas, C; Kiernan, M C; Vucic, S

    2017-06-01

    Amyotrophic lateral sclerosis (ALS) is characterized by focal disease onset with a predominantly contiguous pattern of disease spread. The pathophysiological mechanisms underlying disease progression in ALS have not been elucidated. Given that cortical hyperexcitability has been identified as an important pathogenic mechanism in ALS, the aim of the present study was to determine whether changes in cortical function could mediate disease spread in ALS. Threshold-tracking transcranial magnetic stimulation was undertaken in 50 patients with sporadic ALS with recording of responses over both abductor pollicis brevis muscles, with results matched to clinical assessments and concurrent neurophysiological investigation of lower motor neuron function. Subsequently, patients were followed longitudinally to map patterns of clinical disease progression. Cortical dysfunction was evident over both motor cortices, with hyperexcitability more prominent over the dominant motor cortex, contralateral to the site of disease onset, with reduction of resting motor threshold (F = 3.83, P side of symptom onset, and contributes to a contiguous pattern of spread in sporadic ALS. © 2017 EAN.

  9. The Unique Brain Anatomy of Meditation Practitioners: Alterations in Cortical Gyrification

    Directory of Open Access Journals (Sweden)

    Eileen eLuders

    2012-02-01

    Full Text Available Several cortical regions are reported to vary in meditation practitioners. However, since prior analyses were focused on examining gray matter or cortical thickness, additional effects with respect to other cortical features might have remained undetected. Gyrification (the pattern and degree of cortical folding is an important cerebral characteristic related to the geometry of the brain’s surface. Cortical folding occurs early in development and might be linked to behavioral traits. Thus, exploring cortical gyrification in long-term meditators may provide additional clues with respect to the underlying anatomical correlates of meditation. This study examined cortical gyrification in a large sample (n=100 of meditators and controls, carefully matched for sex and age. Cortical gyrification was established via calculating mean curvature across thousands of vertices on individual cortical surface models. Pronounced group differences indicating larger gyrification in meditators were evident within the left precentral gyrus, right fusiform gyrus, right cuneus, as well as left and right anterior dorsal insula (the latter representing the global significance maximum. Although the exact functional implications of larger cortical gyrification remain to be established, these findings suggest the insula to be a key structure involved in aspects of meditation. For example, variations in insular complexity could affect the regulation of well-known distractions in the process of meditation, such as daydreaming, mind-wandering, and projections into past or future. Moreover, given that meditators are masters in introspection, awareness, and emotional control, increased insular gyrification may reflect an ideal integration of autonomic, affective, and cognitive processes. Due to the cross-sectional nature of this study, further research is necessary determine the relative contribution of nature and nurture to links between cortical gyrification and meditation.

  10. Prenatal thalamic waves regulate cortical area size prior to sensory processing

    Science.gov (United States)

    Moreno-Juan, Verónica; Filipchuk, Anton; Antón-Bolaños, Noelia; Mezzera, Cecilia; Gezelius, Henrik; Andrés, Belen; Rodríguez-Malmierca, Luis; Susín, Rafael; Schaad, Olivier; Iwasato, Takuji; Schüle, Roland; Rutlin, Michael; Nelson, Sacha; Ducret, Sebastien; Valdeolmillos, Miguel; Rijli, Filippo M.; López-Bendito, Guillermina

    2017-01-01

    The cerebral cortex is organized into specialized sensory areas, whose initial territory is determined by intracortical molecular determinants. Yet, sensory cortical area size appears to be fine tuned during development to respond to functional adaptations. Here we demonstrate the existence of a prenatal sub-cortical mechanism that regulates the cortical areas size in mice. This mechanism is mediated by spontaneous thalamic calcium waves that propagate among sensory-modality thalamic nuclei up to the cortex and that provide a means of communication among sensory systems. Wave pattern alterations in one nucleus lead to changes in the pattern of the remaining ones, triggering changes in thalamic gene expression and cortical area size. Thus, silencing calcium waves in the auditory thalamus induces Rorβ upregulation in a neighbouring somatosensory nucleus preluding the enlargement of the barrel-field. These findings reveal that embryonic thalamic calcium waves coordinate cortical sensory area patterning and plasticity prior to sensory information processing. PMID:28155854

  11. Relationship between higher cortical dysfunction and the findings of magnetic resonance imaging in systemic lupus erythematosus

    Energy Technology Data Exchange (ETDEWEB)

    Maeshima, Etsuko; Maeshima, Shinichiro; Yamada, Yoichi; Yukawa, Susumu [Wakayama Medical Coll. (Japan)

    1996-04-01

    The relationship between systemic lupus erythematosus (SLE) and organic lesions was investigated by magnetic resonance imaging (MRI) to clarify the etiology of higher cortical dysfunction in SLE. The subjects were 10 patients with SLE, and higher cortical dysfunction was observed in 8 (80%) of the 10 patients. Five (82.5%) of the 8 patients showed abnormal MRI findings. The findings of higher cortical dysfunction were consistent with the MRI findings in 1 of the 5 patients, but not in the remaining four. MRI revealed no lesion despite the presence of higher cortical dysfunction in three patients. These results suggest that the association of organic changes and functional changes in cerebral nerve cells is important for etiology of higher cortical dysfunction in SLE. (author).

  12. Multilaminar networks of cortical neurons integrate common inputs from sensory thalamus.

    Science.gov (United States)

    Morgenstern, Nicolás A; Bourg, Jacques; Petreanu, Leopoldo

    2016-08-01

    Neurons in the thalamorecipient layers of sensory cortices integrate thalamic and recurrent cortical input. Cortical neurons form fine-scale, functionally cotuned networks, but whether interconnected cortical neurons within a column process common thalamocortical inputs is unknown. We tested how local and thalamocortical connectivity relate to each other by analyzing cofluctuations of evoked responses in cortical neurons after photostimulation of thalamocortical axons. We found that connected pairs of pyramidal neurons in layer (L) 4 of mouse visual cortex share more inputs from the dorsal lateral geniculate nucleus than nonconnected pairs. Vertically aligned connected pairs of L4 and L2/3 neurons were also preferentially contacted by the same thalamocortical axons. Our results provide a circuit mechanism for the observed amplification of sensory responses by L4 circuits. They also show that sensory information is concurrently processed in L4 and L2/3 by columnar networks of interconnected neurons contacted by the same thalamocortical axons.

  13. Sparse imaging of cortical electrical current densities via wavelet transforms

    Science.gov (United States)

    Liao, Ke; Zhu, Min; Ding, Lei; Valette, Sébastien; Zhang, Wenbo; Dickens, Deanna

    2012-11-01

    While the cerebral cortex in the human brain is of functional importance, functions defined on this structure are difficult to analyze spatially due to its highly convoluted irregular geometry. This study developed a novel L1-norm regularization method using a newly proposed multi-resolution face-based wavelet method to estimate cortical electrical activities in electroencephalography (EEG) and magnetoencephalography (MEG) inverse problems. The proposed wavelets were developed based on multi-resolution models built from irregular cortical surface meshes, which were realized in this study too. The multi-resolution wavelet analysis was used to seek sparse representation of cortical current densities in transformed domains, which was expected due to the compressibility of wavelets, and evaluated using Monte Carlo simulations. The EEG/MEG inverse problems were solved with the use of the novel L1-norm regularization method exploring the sparseness in the wavelet domain. The inverse solutions obtained from the new method using MEG data were evaluated by Monte Carlo simulations too. The present results indicated that cortical current densities could be efficiently compressed using the proposed face-based wavelet method, which exhibited better performance than the vertex-based wavelet method. In both simulations and auditory experimental data analysis, the proposed L1-norm regularization method showed better source detection accuracy and less estimation errors than other two classic methods, i.e. weighted minimum norm (wMNE) and cortical low-resolution electromagnetic tomography (cLORETA). This study suggests that the L1-norm regularization method with the use of face-based wavelets is a promising tool for studying functional activations of the human brain.

  14. [Posterior cortical atrophy with progressive visual agnosia].

    Science.gov (United States)

    Zarranz, J J; Lasa, A; Fernández, M; Lezcano, E; Pérez Bas, M; Varona, L; Ruiz, J; Beristain, X

    1995-03-01

    Interest in progressive focal cerebral syndromes associated with classical degenerative diseases has increased in recent years. Descriptions of posterior cortical atrophy with progressive visual agnosia are relatively rare. We present 5 patients (2 women) ranging in age between 57 and 72 years old. In all cases symptoms began and progressed with no known etiology. All cases were sporadic. The main clinical signs are difficulty in recognizing objects, colors, persons or places; topographical disorientation and visual memory alterations; alexia, simultagnosia, loss of ocular fixing and optic ataxia. Some patients presented other disturbances of praxis or memory and 2 progressed to global dementia. Language function was preserved and behavioral disturbances did not develop. The amplitude of the P100 visual evoked potential was low but latency was normal in 4 patients and prolonged in 1. Brain images showed atrophy and hypoperfusion in the parieto-occipital area. The neuropathology status of these patients is unknown.

  15. Association between age of disease-onset, cognitive performance and cortical thickness in bipolar disorders.

    Science.gov (United States)

    Oertel-Knöchel, Viola; Reuter, Johanna; Reinke, Britta; Marbach, Katharina; Feddern, Richard; Alves, Gilberto; Prvulovic, David; Linden, David E J; Knöchel, Christian

    2015-03-15

    Neuroimaging studies in patients with bipolar disorder (BD) have indicated a number of structural brain changes, including reduced cortical thickness. However, the effects of the course of illness, clinical and cognitive variables on cortical thickness in BD patients have not yet been evaluated. A total of 67 individuals (32 patients with euthymic BD and 35 healthy and age-matched controls) underwent 3D-anatomical magnetic resonance imaging (MRI). Whole-brain cortical thickness and group differences were assessed using the Freesurfer software. Course of disease variables, clinical and cognitive parameters were correlated with cortical thickness measures. We found reduced cortical thickness in BD patients compared with controls in the frontal and temporal lobes and in several limbic areas. We also report significant associations between cortical thickness and age of disease-onset, speed of cognitive processing, executive function and depression severity in BD patients. Cortical thickness reduction across frontal and limbic areas is a structural correlate of affective symptom severity and cognitive impairments in BD as well of age of disease-onset. We may assume that frontal lobe structural abnormalities are present in bipolar disorder, and might lead to dysfunctional cognitive functioning. The causality and functional relevance beyond mere correlation, however, is yet to be established. Our findings encourage further longitudinal studies in BD patients and in healthy at-risk subjects in order to discern the temporal order and development of morphological changes and clinical symptoms. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Regional quantitative analysis of cortical surface maps of FDG PET images

    CERN Document Server

    Protas, H D; Hayashi, K M; Chin Lung, Yu; Bergsneider, M; Sung Cheng, Huang

    2006-01-01

    Cortical surface maps are advantageous for visualizing the 3D profile of cortical gray matter development and atrophy, and for integrating structural and functional images. In addition, cortical surface maps for PET data, when analyzed in conjunction with structural MRI data allow us to investigate, and correct for, partial volume effects. Here we compared quantitative regional PET values based on a 3D cortical surface modeling approach with values obtained directly from the 3D FDG PET images in various atlas-defined regions of interest (ROIs; temporal, parietal, frontal, and occipital lobes). FDG PET and 3D MR (SPGR) images were obtained and aligned to ICBM space for 15 normal subjects. Each image was further elastically warped in 2D parameter space of the cortical surface, to align major cortical sulci. For each point within a 15 mm distance of the cortex, the value of the PET intensity was averaged to give a cortical surface map of FDG uptake. The average PET values on the cortical surface map were calcula...

  17. Development and maturation of embryonic cortical neurons grafted into the damaged adult motor cortex

    Directory of Open Access Journals (Sweden)

    Nissrine Ballout

    2016-08-01

    Full Text Available Injury to the human central nervous system can lead to devastating consequences due to its poor ability to self-repair. Neural transplantation aimed at replacing lost neurons and restore functional circuitry has proven to be a promising therapeutical avenue. We previously reported in adult rodent animal models with cortical lesions that grafted fetal cortical neurons could effectively re-establish specific patterns of projections and synapses. The current study was designed to provide a detailed characterization of the spatio-temporal in vivo development of fetal cortical transplanted cells within the lesioned adult motor cortex and their corresponding axonal projections. We show here that as early as two weeks after grafting, cortical neuroblasts transplanted into damaged adult motor cortex developed appropriate projections to cortical and subcortical targets. Grafted cells initially exhibited characteristics of immature neurons, which then differentiated into mature neurons with appropriate cortical phenotypes where most were glutamatergic and few were GABAergic. All cortical subtypes identified with the specific markers CTIP2, Cux1, FOXP2 and Tbr1 were generated after grafting as evidenced with BrdU co-labeling.The set of data provided here is of interest as it sets biological standards for future studies aimed at replacing fetal cells with embryonic stem cells as a source of cortical neurons.

  18. Acute hepatic encephalopathy with diffuse cortical lesions

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, S.M.; Spreer, J.; Schumacher, M. [Section of Neuroradiology, Univ. of Freiburg (Germany); Els, T. [Dept. of Neurology, University of Freiburg (Germany)

    2001-07-01

    Acute hepatic encephalopathy is a poorly defined syndrome of heterogeneous aetiology. We report a 49-year-old woman with alcoholic cirrhosis and hereditary haemorrhagic telangiectasia who developed acute hepatic coma induced by severe gastrointestinal bleeding. Laboratory analysis revealed excessively elevated blood ammonia. MRI showed lesions compatible with chronic hepatic encephalopathy and widespread cortical signal change sparing the perirolandic and occipital cortex. The cortical lesions resembled those of hypoxic brain damage and were interpreted as acute toxic cortical laminar necrosis. (orig.)

  19. Early detection of AD using cortical thickness measurements

    Science.gov (United States)

    Spjuth, M.; Gravesen, F.; Eskildsen, S. F.; Østergaard, L. R.

    2007-03-01

    Alzheimer's disease (AD) is a neurodegenerative disorder that causes cortical atrophy and impaired cognitive functions. The diagnosis is difficult to make and is often made over a longer period of time using a combination of neuropsychological tests, and structural and functional imaging. Due to the impact of early intervention the challenge of distinguishing early AD from normal ageing has received increasing attention. This study uses cortical thickness measurements to characterize the atrophy in nine mild AD patients (mean MMSE-score 23.3 (std: 2.6)) compared to five healthy middle-aged subjects. A fully automated method based on deformable models is used for delineation of the inner and outer boundaries of the cerebral cortex from Magnetic Resonance Images. This allows observer independent high-resolution quantification of the cortical thickness. The cortex analysis facilitates detection of alterations throughout the entire cortical mantle. To perform inter-subject thickness comparison in which the spatial information is retained, a feature-based registration algorithm is developed which uses local cortical curvature, normal vector, and a distance measure. A comparison of the two study groups reveals that the lateral side of the hemispheres shows diffuse thinner areas in the mild AD group but especially the medial side shows a pronounced thinner area which can be explained by early limbic changes in AD. For classification principal component analysis is applied to reduce the high number of thickness measurements (>200,000) into fewer features. All mild AD and healthy middle-aged subjects are classified correctly (sensitivity and specificity 100%).

  20. Decreased cortical inhibition and yet cerebellar pathology in 'familial cortical myoclonic tremor with epilepsy'

    NARCIS (Netherlands)

    van Rootselaar, Anne-Fleur; van der Salm, Sandra M. A.; Bour, Lo J.; Edwards, Mark J.; Brown, Peter; Aronica, Eleonora; Rozemuller-Kwakkel, Johanna M.; Koehler, Peter J.; Koelman, Johannes H. T. M.; Rothwell, John C.; Tijssen, Marina A. J.

    2007-01-01

    Cortical hyperexcitability is a feature of "familial cortical myoclonic tremor with epilepsy" (FCMTE). However, neuropathological investigations in a single FCMTE patient showed isolated cerebellar pathology. Pathological investigations in a second FCMTE patient, reported here, confirmed cerebellar

  1. Frontal Cortical Atrophy as a Predictor of Poststroke Apathy.

    Science.gov (United States)

    Mihalov, Ján; Mikula, Peter; Budiš, Jaroslav; Valkovič, Peter

    2016-07-01

    The aim of the study was to identify associations between the symptoms of poststroke apathy and sociodemographic, stroke-related (severity of stroke, degree of disability, and performance in activities of daily living), and radiological correlates. We determined the degree of cortical and subcortical brain atrophy, the severity of white matter and basal ganglia lesions on baseline computed tomography (CT) scans, and the localization of acute ischemia on control CT or magnetic resonance imaging scans in subacute stages of stroke. During follow-up examinations, in addition to the assessment of apathy symptoms using the Apathy Scale, we also evaluated symptoms of depression and anxiety using the Hospital Anxiety and Depression Scale. The study included 47 consecutive patients with acute ischemic stroke. Correlates significantly associated with apathy, determined at baseline and during follow-up, were entered into the "predictive" and "associative" multiple regression models, respectively. Frontal cortical atrophy and symptoms of depression were most strongly associated with poststroke apathy symptoms. In order to model an interrelation between both cortical atrophy and white matter lesions and aging, we supplemented 2 additional "predictive" models using interaction variables, whereby we confirmed the role of frontal cortical atrophy as a predictor of poststroke apathy also as a function of the increasing age of patients. © The Author(s) 2016.

  2. Calmodulin immunolocalization to cortical microtubules is calcium independent

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, D.D.; Cyr, R.J.

    1992-01-01

    Calcium affects the stability of cortical microtubules (MTs) in lysed protoplasts. This calmodulin (CaM)-mediated interaction may provide a mechanism that serves to integrate cellular behavior with MT function. To test the hypothesis that CaM associates with these MTs, monoclonal antibodies were produced against CaM, and one (designated mAb1D10), was selected for its suitability as an immunocytochemical reagent. It is shown that CaM associates with the cortical Mats of cultured carrot (Daucus carota L.) and tobacco (Nicotiana tobacum L.) cells. Inasmuch as CaM interacts with calcium and affects the behavior of these Mats, we hypothesized that calcium would alter this association. To test this, protoplasts containing taxol-stabilized Mats were lysed in the presence of various concentrations of calcium and examined for the association of Cam with cortical Mats. At 1 [mu]M calcium, many protoplasts did not have CaM in association with the cortical Mats, while at 3.6 [mu]M calcium, this association was completely abolished. The results are discussed in terms of a model in which CaM associates with Mats via two types of interactions; one calcium dependent and one independent.

  3. Calmodulin immunolocalization to cortical microtubules is calcium independent

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, D.D.; Cyr, R.J.

    1992-12-31

    Calcium affects the stability of cortical microtubules (MTs) in lysed protoplasts. This calmodulin (CaM)-mediated interaction may provide a mechanism that serves to integrate cellular behavior with MT function. To test the hypothesis that CaM associates with these MTs, monoclonal antibodies were produced against CaM, and one (designated mAb1D10), was selected for its suitability as an immunocytochemical reagent. It is shown that CaM associates with the cortical Mats of cultured carrot (Daucus carota L.) and tobacco (Nicotiana tobacum L.) cells. Inasmuch as CaM interacts with calcium and affects the behavior of these Mats, we hypothesized that calcium would alter this association. To test this, protoplasts containing taxol-stabilized Mats were lysed in the presence of various concentrations of calcium and examined for the association of Cam with cortical Mats. At 1 {mu}M calcium, many protoplasts did not have CaM in association with the cortical Mats, while at 3.6 {mu}M calcium, this association was completely abolished. The results are discussed in terms of a model in which CaM associates with Mats via two types of interactions; one calcium dependent and one independent.

  4. Testosterone-Related Cortical Maturation Across Childhood and Adolescence

    Science.gov (United States)

    Nguyen, Tuong-Vi; McCracken, James; Ducharme, Simon; Botteron, Kelly N.; Mahabir, Megan; Johnson, Wendy; Israel, Mimi; Evans, Alan C.; Karama, Sherif

    2013-01-01

    Neuroendocrine theories of brain development hold testosterone as the predominant factor mediating sex-specific cortical growth and the ensuing lateralization of hemispheric function. However, studies to date have focussed on prenatal testosterone rather than pubertal changes in testosterone. Yet, animal studies have shown a high density of androgen-sensitive receptors in multiple key cortical areas, and puberty is known to coincide with both a significant rise in testosterone and the emergence of behavioral sex differences, suggesting peripubertal influences of testosterone on brain development. Here, we used linear mixed models to examine sex-specific cortical maturation associated with changes in testosterone levels in a longitudinal sample of developmentally healthy children and adolescents. A significant “sex by age by testosterone” interaction on cortical thickness (CTh) involving widespread areas of the developing brain was found. Testosterone levels were associated with CTh changes in regions of the left hemisphere in males and of the right hemisphere in females. In both sexes, the relationship between testosterone and CTh varied across the age span. These findings show the association between testosterone and CTh to be complex, highly dynamic, and to vary, depending on sex and age; they also suggest sex-related hemispheric lateralization effects of testosterone in humans. PMID:22617851

  5. Cortical control of facial expression.

    Science.gov (United States)

    Müri, René M

    2016-06-01

    The present Review deals with the motor control of facial expressions in humans. Facial expressions are a central part of human communication. Emotional face expressions have a crucial role in human nonverbal behavior, allowing a rapid transfer of information between individuals. Facial expressions can be either voluntarily or emotionally controlled. Recent studies in nonhuman primates and humans have revealed that the motor control of facial expressions has a distributed neural representation. At least five cortical regions on the medial and lateral aspects of each hemisphere are involved: the primary motor cortex, the ventral lateral premotor cortex, the supplementary motor area on the medial wall, and the rostral and caudal cingulate cortex. The results of studies in humans and nonhuman primates suggest that the innervation of the face is bilaterally controlled for the upper part and mainly contralaterally controlled for the lower part. Furthermore, the primary motor cortex, the ventral lateral premotor cortex, and the supplementary motor area are essential for the voluntary control of facial expressions. In contrast, the cingulate cortical areas are important for emotional expression, because they receive input from different structures of the limbic system. © 2015 Wiley Periodicals, Inc.

  6. Motor-cortical interaction in Gilles de la Tourette syndrome.

    Directory of Open Access Journals (Sweden)

    Stephanie Franzkowiak

    Full Text Available BACKGROUND: In Gilles de la Tourette syndrome (GTS increased activation of the primary motor cortex (M1 before and during movement execution followed by increased inhibition after movement termination was reported. The present study aimed at investigating, whether this activation pattern is due to altered functional interaction between motor cortical areas. METHODOLOGY/PRINCIPAL FINDINGS: 10 GTS-patients and 10 control subjects performed a self-paced finger movement task while neuromagnetic brain activity was recorded using Magnetoencephalography (MEG. Cerebro-cerebral coherence as a measure of functional interaction was calculated. During movement preparation and execution coherence between contralateral M1 and supplementary motor area (SMA was significantly increased at beta-frequency in GTS-patients. After movement termination no significant differences between groups were evident. CONCLUSIONS/SIGNIFICANCE: The present data suggest that increased M1 activation in GTS-patients might be due to increased functional interaction between SMA and M1 most likely reflecting a pathophysiological marker of GTS. The data extend previous findings of motor-cortical alterations in GTS by showing that local activation changes are associated with alterations of functional networks between premotor and primary motor areas. Interestingly enough, alterations were evident during preparation and execution of voluntary movements, which implies a general theme of increased motor-cortical interaction in GTS.

  7. Cortical neuroplasticity in patients recovering from acute optic neuritis

    DEFF Research Database (Denmark)

    Korsholm, Kirsten; Madsen, Kristoffer Hougaard; Frederiksen, Jette L.

    2008-01-01

    Patients with optic neuritis (ON) undergo cortical and subcortical neuroplasticity as revealed by functional magnetic resonance imaging (fMRI). However, the effect of the heterogeneity of scotomas his not been adequately addressed previously. We introduce a new method of modelling scotomas in f......MRI, to reveal a clearer pattern of neuroplasticity, across a mixed patient population. A longitudinal fMRI-study of visual function in 19 ON patients examined at four timepoints between presentation and 6 months was performed. Four different models were compared. The first model included the four different...... Cortical neuroplasticity during recovery. Moreover, inferences from the fourth model can be extended to the general Population of patients recovering from ON. In Conclusion, we present a method of accommodating subject-specific differences between patients with acute ON by inclusion of an HMD...

  8. Learning in AN Oscillatory Cortical Model

    Science.gov (United States)

    Scarpetta, Silvia; Li, Zhaoping; Hertz, John

    We study a model of generalized-Hebbian learning in asymmetric oscillatory neural networks modeling cortical areas such as hippocampus and olfactory cortex. The learning rule is based on the synaptic plasticity observed experimentally, in particular long-term potentiation and long-term depression of the synaptic efficacies depending on the relative timing of the pre- and postsynaptic activities during learning. The learned memory or representational states can be encoded by both the amplitude and the phase patterns of the oscillating neural populations, enabling more efficient and robust information coding than in conventional models of associative memory or input representation. Depending on the class of nonlinearity of the activation function, the model can function as an associative memory for oscillatory patterns (nonlinearity of class II) or can generalize from or interpolate between the learned states, appropriate for the function of input representation (nonlinearity of class I). In the former case, simulations of the model exhibits a first order transition between the "disordered state" and the "ordered" memory state.

  9. Primary sensory cortices contain distinguishable spatial patterns of activity for each sense.

    Science.gov (United States)

    Liang, M; Mouraux, A; Hu, L; Iannetti, G D

    2013-01-01

    Whether primary sensory cortices are essentially multisensory or whether they respond to only one sense is an emerging debate in neuroscience. Here we use a multivariate pattern analysis of functional magnetic resonance imaging data in humans to demonstrate that simple and isolated stimuli of one sense elicit distinguishable spatial patterns of neuronal responses, not only in their corresponding primary sensory cortex, but in other primary sensory cortices. These results indicate that primary sensory cortices, traditionally regarded as unisensory, contain unique signatures of other senses and, thereby, prompt a reconsideration of how sensory information is coded in the human brain.

  10. Endogenous cortical rhythms determine cerebral specialization for speech perception and production

    DEFF Research Database (Denmark)

    Giraud, Anne-Lise; Kleinschmidt, Andreas; Poeppel, David

    2007-01-01

    Across multiple timescales, acoustic regularities of speech match rhythmic properties of both the auditory and motor systems. Syllabic rate corresponds to natural jaw-associated oscillatory rhythms, and phonemic length could reflect endogenous oscillatory auditory cortical properties. Hemispheric...... lateralization for speech could result from an asymmetry of cortical tuning, with left and right auditory areas differentially sensitive to spectro-temporal features of speech. Using simultaneous electroencephalographic (EEG) and functional magnetic resonance imaging (fMRI) recordings from humans, we show......, indicating coupling between temporal properties of speech perception and production. These data show that endogenous cortical rhythms provide temporal and spatial constraints on the neuronal mechanisms underlying speech perception and production....

  11. Protein Kinase C Overactivity Impairs Prefrontal Cortical Regulation of Working Memory

    Science.gov (United States)

    Birnbaum, S. G.; Yuan, P. X.; Wang, M.; Vijayraghavan, S.; Bloom, A. K.; Davis, D. J.; Gobeske, K. T.; Sweatt, J. D.; Manji, H. K.; Arnsten, A. F. T.

    2004-10-01

    The prefrontal cortex is a higher brain region that regulates thought, behavior, and emotion using representational knowledge, operations often referred to as working memory. We tested the influence of protein kinase C (PKC) intracellular signaling on prefrontal cortical cognitive function and showed that high levels of PKC activity in prefrontal cortex, as seen for example during stress exposure, markedly impair behavioral and electrophysiological measures of working memory. These data suggest that excessive PKC activation can disrupt prefrontal cortical regulation of behavior and thought, possibly contributing to signs of prefrontal cortical dysfunction such as distractibility, impaired judgment, impulsivity, and thought disorder.

  12. Task-Modulated Cortical Representations of Natural Sound Source Categories

    DEFF Research Database (Denmark)

    Hjortkjær, Jens; Kassuba, Tanja; Madsen, Kristoffer Hougaard

    2018-01-01

    In everyday sound environments, we recognize sound sources and events by attending to relevant aspects of an acoustic input. Evidence about the cortical mechanisms involved in extracting relevant category information from natural sounds is, however, limited to speech. Here, we used functional MRI...... discriminability. Action categories were more accurately decoded in auditory cortex when subjects identified action information. Conversely, the material of the same sound sources was decoded with higher accuracy in the inferior frontal cortex during material identification. Representational similarity analyses...

  13. High-expanding cortical regions in human development and evolution are related to higher intellectual abilities.

    Science.gov (United States)

    Fjell, Anders M; Westlye, Lars T; Amlien, Inge; Tamnes, Christian K; Grydeland, Håkon; Engvig, Andreas; Espeseth, Thomas; Reinvang, Ivar; Lundervold, Astri J; Lundervold, Arvid; Walhovd, Kristine B

    2015-01-01

    Cortical surface area has tremendously expanded during human evolution, and similar patterns of cortical expansion have been observed during childhood development. An intriguing hypothesis is that the high-expanding cortical regions also show the strongest correlations with intellectual function in humans. However, we do not know how the regional distribution of correlations between intellectual function and cortical area maps onto expansion in development and evolution. Here, in a sample of 1048 participants, we show that regions in which cortical area correlates with visuospatial reasoning abilities are generally high expanding in both development and evolution. Several regions in the frontal cortex, especially the anterior cingulate, showed high expansion in both development and evolution. The area of these regions was related to intellectual functions in humans. Low-expanding areas were not related to cognitive scores. These findings suggest that cortical regions involved in higher intellectual functions have expanded the most during development and evolution. The radial unit hypothesis provides a common framework for interpretation of the findings in the context of evolution and prenatal development, while additional cellular mechanisms, such as synaptogenesis, gliogenesis, dendritic arborization, and intracortical myelination, likely impact area expansion in later childhood. © The Author 2013. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  14. Primary visual cortical remapping in patients with inherited peripheral retinal degeneration.

    Science.gov (United States)

    Ferreira, Sónia; Pereira, Andreia Carvalho; Quendera, Bruno; Reis, Aldina; Silva, Eduardo Duarte; Castelo-Branco, Miguel

    2017-01-01

    Human studies addressing the long-term effects of peripheral retinal degeneration on visual cortical function and structure are scarce. Here we investigated this question in patients with Retinitis Pigmentosa (RP), a genetic condition leading to peripheral visual degeneration. We acquired functional and anatomical magnetic resonance data from thirteen patients with different levels of visual loss and twenty-two healthy participants to study primary (V1) visual cortical retinotopic remapping and cortical thickness. We identified systematic visual field remapping in the absence of structural changes in the primary visual cortex of RP patients. Remapping consisted in a retinotopic eccentricity shift of central retinal inputs to more peripheral locations in V1. Importantly, this was associated with changes in visual experience, as assessed by the extent of the visual loss, with more constricted visual fields resulting in larger remapping. This pattern of remapping is consistent with expansion or shifting of neuronal receptive fields into the cortical regions with reduced retinal input. These data provide evidence for functional changes in V1 that are dependent on the magnitude of peripheral visual loss in RP, which may be explained by rapid cortical adaptation mechanisms or long-term cortical reorganization. This study highlights the importance of analyzing the retinal determinants of brain functional and structural alterations for future visual restoration approaches.

  15. EEG-guided transcranial magnetic stimulation reveals rapid shifts in motor cortical excitability during the human sleep slow oscillation

    DEFF Research Database (Denmark)

    Bergmann, Til O; Mölle, Matthias; Schmidt, Marlit A

    2012-01-01

    Evoked cortical responses do not follow a rigid input-output function but are dynamically shaped by intrinsic neural properties at the time of stimulation. Recent research has emphasized the role of oscillatory activity in determining cortical excitability. Here we employed EEG-guided transcranial...

  16. Electrical Stimulation of Visual Cortex: Relevance for the Development of Visual Cortical Prosthetics.

    Science.gov (United States)

    Bosking, William H; Beauchamp, Michael S; Yoshor, Daniel

    2017-09-15

    Electrical stimulation of the cerebral cortex is a powerful tool for exploring cortical function. Stimulation of early visual cortical areas is easily detected by subjects and produces simple visual percepts known as phosphenes. A device implanted in visual cortex that generates patterns of phosphenes could be used as a substitute for natural vision in blind patients. We review the possibilities and limitations of such a device, termed a visual cortical prosthetic. Currently, we can predict the location and size of phosphenes produced by stimulation of single electrodes. A functional prosthetic, however, must produce spatial temporal patterns of activity that will result in the perception of complex visual objects. Although stimulation of later visual cortical areas alone usually does not lead to a visual percept, it can alter visual perception and the performance of visual behaviors, and training subjects to use signals injected into these areas may be possible.

  17. Cortical activation during balancing on a balance board.

    Science.gov (United States)

    Herold, Fabian; Orlowski, Katja; Börmel, Sabrina; Müller, Notger G

    2017-01-01

    Keeping one's balance is a complex motor task which requires the integration and processing of different sensory information. For this, higher cortical processes are essential. However, in the past research dedicated to the brain's involvement in balance control has predominantly used virtual reality paradigms whilst little is known about cortical activation during the challenging balancing on unstable surfaces (e.g. balance board). Hence, the main goal of this study was the simultaneous evaluation of cortical activation patterns and sway parameters during balancing on a balance board. Ten healthy adults were instructed to balance on a balance board while brain activation in supplementary motor area (SMA), precentral gyrus (PrG) and postcentral gyrus (PoG) was measured with functional near-infrared spectroscopy (fNIRS). Additionally, sway parameters were simultaneously recorded with one inertial sensor. Enhanced activation of SMA, PrG and PoG was observed when balancing was compared with still standing. Furthermore, the sway of pelvis (indicated by root mean square) increased in medio-lateral (ML) and anterior-posterior (AP) direction during the balance condition. Notably, a strong negative correlation was found between SMA activation and sway in ML direction during balancing, which was not observed during standing. Our results underline the important role of sensorimotor cortical areas for balance control. Moreover, the observed correlations suggest a crucial involvement of SMA in online control of sway in ML direction. Further research is needed to understand the contribution of other cortical and subcortcial areas to online balance control. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Cortical hypermetabolism in MCI subjects: a compensatory mechanism?

    Energy Technology Data Exchange (ETDEWEB)

    Ashraf, A.; Fan, Z.; Brooks, D.J.; Edison, P. [Imperial College London, Neurology Imaging Unit, Division of Brain Sciences, London (United Kingdom)

    2014-09-30

    Alzheimer's disease (AD) is associated with amyloid accumulation that takes place decades before symptoms appear. Cognitive impairment in AD is associated with reduced glucose metabolism. However, neuronal plasticity/compensatory mechanisms might come into play before the onset of dementia. The aim of this study was to determine whether there is evidence of cortical hypermetabolism as a compensatory mechanism before amyloid deposition takes place in subjects with amnestic mild cognitive impairment (aMCI). Nine AD subjects and ten aMCI subjects had both [{sup 11}C]PIB and [{sup 18}F]FDG PET scans with arterial input in order to quantify the amyloid deposition and glucose metabolism in vivo in comparison with healthy control subjects who underwent either [{sup 11}C]PIB or [{sup 18}F]FDG PET scans. The [{sup 11}C]PIB PET scans were quantified using [{sup 11}C]PIB target region to cerebellum uptake ratio images created by integrating the activity collected from 60 to 90 min, and regional cerebral glucose metabolism was quantified using spectral analysis. In MCI subjects, cortical hypermetabolism was observed in four amyloid-negative subjects and one amyloid-positive subject, while hypometabolism was seen in five other MCI subjects with high amyloid load. Subjects with hypermetabolism and low amyloid did not convert to AD during clinical follow-up for 18 months in contrast to four amyloid-positive hypometabolic subjects who did convert to AD. This preliminary study suggests that compensatory hypermetabolism can occur in aMCI subjects, particularly in those who are amyloid-negative. The increase in metabolic rate in different cortical regions with predominance in the occipital cortex may be a compensatory response to the neuronal damage occurring early in the disease process. It may also reflect recruitment of relatively minimally affected cortical regions to compensate for reduced function in the temporoparietal cortical association areas. (orig.)

  19. Abnormal cortical networks in mild cognitive impairment and Alzheimer's disease.

    Directory of Open Access Journals (Sweden)

    Zhijun Yao

    2010-11-01

    Full Text Available Recently, many researchers have used graph theory to study the aberrant brain structures in Alzheimer's disease (AD and have made great progress. However, the characteristics of the cortical network in Mild Cognitive Impairment (MCI are still largely unexplored. In this study, the gray matter volumes obtained from magnetic resonance imaging (MRI for all brain regions except the cerebellum were parcellated into 90 areas using the automated anatomical labeling (AAL template to construct cortical networks for 98 normal controls (NCs, 113 MCIs and 91 ADs. The measurements of the network properties were calculated for each of the three groups respectively. We found that all three cortical networks exhibited small-world properties and those strong interhemispheric correlations existed between bilaterally homologous regions. Among the three cortical networks, we found the greatest clustering coefficient and the longest absolute path length in AD, which might indicate that the organization of the cortical network was the least optimal in AD. The small-world measures of the MCI network exhibited intermediate values. This finding is logical given that MCI is considered to be the transitional stage between normal aging and AD. Out of all the between-group differences in the clustering coefficient and absolute path length, only the differences between the AD and normal control groups were statistically significant. Compared with the normal controls, the MCI and AD groups retained their hub regions in the frontal lobe but showed a loss of hub regions in the temporal lobe. In addition, altered interregional correlations were detected in the parahippocampus gyrus, medial temporal lobe, cingulum, fusiform, medial frontal lobe, and orbital frontal gyrus in groups with MCI and AD. Similar to previous studies of functional connectivity, we also revealed increased interregional correlations within the local brain lobes and disrupted long distance interregional

  20. Bicycling and Walking are Associated with Different Cortical Oscillatory Dynamics

    Science.gov (United States)

    Storzer, Lena; Butz, Markus; Hirschmann, Jan; Abbasi, Omid; Gratkowski, Maciej; Saupe, Dietmar; Schnitzler, Alfons; Dalal, Sarang S.

    2016-01-01

    Although bicycling and walking involve similar complex coordinated movements, surprisingly Parkinson’s patients with freezing of gait typically remain able to bicycle despite severe difficulties in walking. This observation suggests functional differences in the motor networks subserving bicycling and walking. However, a direct comparison of brain activity related to bicycling and walking has never been performed, neither in healthy participants nor in patients. Such a comparison could potentially help elucidating the cortical involvement in motor control and the mechanisms through which bicycling ability may be preserved in patients with freezing of gait. The aim of this study was to contrast the cortical oscillatory dynamics involved in bicycling and walking in healthy participants. To this end, EEG and EMG data of 14 healthy participants were analyzed, who cycled on a stationary bicycle at a slow cadence of 40 revolutions per minute (rpm) and walked at 40 strides per minute (spm), respectively. Relative to walking, bicycling was associated with a stronger power decrease in the high beta band (23–35 Hz) during movement initiation and execution, followed by a stronger beta power increase after movement termination. Walking, on the other hand, was characterized by a stronger and persisting alpha power (8–12 Hz) decrease. Both bicycling and walking exhibited movement cycle-dependent power modulation in the 24–40 Hz range that was correlated with EMG activity. This modulation was significantly stronger in walking. The present findings reveal differential cortical oscillatory dynamics in motor control for two types of complex coordinated motor behavior, i.e., bicycling and walking. Bicycling was associated with a stronger sustained cortical activation as indicated by the stronger high beta power decrease during movement execution and less cortical motor control within the movement cycle. We speculate this to be due to the more continuous nature of bicycling

  1. Histologic changes in selenite cortical cataract.

    Science.gov (United States)

    Anderson, R S; Trune, D R; Shearer, T R

    1988-09-01

    Massive cortical cataract was produced 15-30 days after a single injection of an overdose of sodium selenite into 14-day-old rats. Most of the cortical cataract appeared to be due to extensive liquefaction of cortical fibers. Water influx, following initial damage to the epithelium by selenium, and action of lens proteases were probable mechanisms for the extensive liquefaction. Remarkably, selenite cortical cataract spontaneously cleared after several months, restoring essentially normal cells to the epithelium and outer and mid-cortex. Major mechanisms for clearing probably involved: (1) removal of damaged proteins from the lens by extensive proteolysis; and (2) replacement of fibers by resumption of normal fibergenesis. The data emphasized the remarkable reparative potential of the lens, and indicated the usefulness of the selenite cortical cataract as a model to study such processes.

  2. Cortical cartography and Caret software.

    Science.gov (United States)

    Van Essen, David C

    2012-08-15

    Caret software is widely used for analyzing and visualizing many types of fMRI data, often in conjunction with experimental data from other modalities. This article places Caret's development in a historical context that spans three decades of brain mapping--from the early days of manually generated flat maps to the nascent field of human connectomics. It also highlights some of Caret's distinctive capabilities. This includes the ease of visualizing data on surfaces and/or volumes and on atlases as well as individual subjects. Caret can display many types of experimental data using various combinations of overlays (e.g., fMRI activation maps, cortical parcellations, areal boundaries), and it has other features that facilitate the analysis and visualization of complex neuroimaging datasets. Copyright © 2011 Elsevier Inc. All rights reserved.

  3. Unsupervised fetal cortical surface parcellation

    Science.gov (United States)

    Dahdouh, Sonia; Limperopoulos, Catherine

    2016-03-01

    At the core of many neuro-imaging studies, atlas-based brain parcellations are used for example to study normal brain evolution across the lifespan. These atlases rely on the assumption that the same anatomical features are present on all subjects to be studied and that these features are stable enough to allow meaningful comparisons between different brain surfaces and structures These methods, however, often fail when applied to fetal MRI data, due to the lack of consistent anatomical features present across gestation. This paper presents a novel surface-based fetal cortical parcellation framework which attempts to circumvent the lack of consistent anatomical features by proposing a brain parcellation scheme that is based solely on learned geometrical features. A mesh signature incorporating both extrinsic and intrinsic geometrical features is proposed and used in a clustering scheme to define a parcellation of the fetal brain. This parcellation is then learned using a Random Forest (RF) based learning approach and then further refined in an alpha-expansion graph-cut scheme. Based on the votes obtained by the RF inference procedure, a probability map is computed and used as a data term in the graph-cut procedure. The smoothness term is defined by learning a transition matrix based on the dihedral angles of the faces. Qualitative and quantitative results on a cohort of both healthy and high-risk fetuses are presented. Both visual and quantitative assessments show good results demonstrating a reliable method for fetal brain data and the possibility of obtaining a parcellation of the fetal cortical surfaces using only geometrical features.

  4. The effect of sleep deprivation on cortical excitability – a neuromagnetic approach.

    OpenAIRE

    Rekola, Lauri

    2017-01-01

    Despite decades of study, no ironclad conclusion has been reached concerning the biological function of sleep in humans. Recent theories have proposed that sleep might play a role in maintaining cortical excitability at safe levels by downregulating excessive intersynaptic connections accumulated during a waking episode. In line with this theory, sleep deprivation has been shown to increase cortical excitability in studies using transcranial magnetic stimulation (TMS) and electroencephalograp...

  5. Abnormal dopaminergic modulation of striato-cortical networks underlies levodopa-induced dyskinesias in humans

    DEFF Research Database (Denmark)

    Herz, Damian M.; Haagensen, Brian N.; Christensen, Mark S.

    2015-01-01

    Dopaminergic signalling in the striatum contributes to reinforcement of actions and motivational enhancement of motor vigour. Parkinson's disease leads to progressive dopaminergic denervation of the striatum, impairing the function of cortico-basal ganglia networks. While levodopa therapy......-cortical connectivity as a neural signature of levodopa-induced dyskinesias in humans. We argue that excessive striato-cortical connectivity in response to levodopa produces an aberrant reinforcement signal producing an abnormal motor drive that ultimately triggers involuntary movements....

  6. Longitudinal MRI study of cortical thickness, perfusion, and metabolite levels in major depressive disorder

    DEFF Research Database (Denmark)

    Järnum, Hanna; Eskildsen, Simon Fristed; Steffensen, Elena G.

    2011-01-01

    disorder (MDD) display morphologic, functional, and metabolic brain abnormalities in limbic-cortical regions at a baseline magnetic resonance (MR) scan and whether these changes are normalized in MDD patients in remission at a follow-up scan. Method:  A longitudinal 3.0-Tesla (T) magnetic resonance imaging...... with healthy controls at baseline. Conclusion:  Using novel MRI techniques, we have found abnormalities in cerebral regions related to cortical-limbic pathways in MDD patients....

  7. Thalamo-cortical connectivity: what can diffusion tractography tell us about reading difficulties in children?

    Science.gov (United States)

    Fan, Qiuyun; Davis, Nicole; Anderson, Adam W; Cutting, Laurie E

    2014-08-01

    Reading is an essential skill in modern society, but many people have deficits in the decoding and word recognition aspects of reading, a difficulty often referred to as dyslexia. The primary focus of neuroimaging studies to date in dyslexia has been on cortical regions; however, subcortical regions may also be important for explaining this disability. Here, we used diffusion tensor imaging to examine the association between thalamo-cortical connectivity and children's reading ability in 20 children with typically developed reading ability (age range 8-17/10-17 years old from two imaging centers) and 19 children with developmental dyslexia (DYS) (age range 9-17/9-16 years old). To measure thalamo-cortical connections, the structural images were segmented into cortical and subcortical anatomical regions that were used as target and seed regions in the probabilistic tractography analysis. Abnormal thalamic connectivity was found in the dyslexic group in the sensorimotor and lateral prefrontal cortices. These results suggest that the thalamus may play a key role in reading behavior by mediating the functions of task-specific cortical regions; such findings lay the foundation for future studies to investigate further neurobiological anomalies in the development of thalamo-cortical connectivity in DYS.

  8. Synaptotagmin I is involved in the regulation of cortical granule exocytosis in the sea urchin.

    Science.gov (United States)

    Leguia, Mariana; Conner, Sean; Berg, Linnea; Wessel, Gary M

    2006-07-01

    Cortical granules are stimulus-dependent secretory vesicles found in the egg cortex of most vertebrates and many invertebrates. Upon fertilization, an increase in intracellular calcium levels triggers cortical granules to exocytose enzymes and structural proteins that permanently modify the extracellular surface of the egg to prevent polyspermy. Synaptotagmin is postulated to be a calcium sensor important for stimulus-dependent secretion and to test this hypothesis for cortical granule exocytosis, we identified the ortholog in two sea urchin species that is present selectively on cortical granules. Characterization by RT-PCR, in-situ RNA hybridization, Western blot and immunolocalization shows that synaptotagmin I is expressed in a manner consistent with it having a role during cortical granule secretion. We specifically tested synaptotagmin function during cortical granule exocytosis using a microinjected antibody raised against the entire cytoplasmic domain of sea urchin synaptotagmin I. The results show that synaptotagmin I is essential for normal cortical granule dynamics at fertilization in the sea urchin egg. Identification of this same protein in other developmental stages also shown here will be important for interpreting stimulus-dependent secretory events for signaling throughout embryogenesis.

  9. Cortical damage in the posterior visual pathway in patients with sialidosis type 1.

    Science.gov (United States)

    Lu, Chin-Song; Ng, Shu-Hang; Lai, Szu-Chia; Kao, Ling-Yuh; Liu, Laura; Lin, Wey-Yil; Wu, Yi-Ming; Chen, Yao-Liang; Wang, Jiun-Jie

    2017-02-01

    In order to identify the cortical changes in patients with Sialidosis type 1, diffusion tensor imaging and resting state fMRI were acquired from 11 patients and 11 sex/age matched normal controls after clinical evaluations. The neuroimages from each participant were normalized and parcellated according to the Automatic Anatomical Labeling. Both the mean diffusivity and the corresponding functional connectivity were calculated from each cortical region. The white matter tract integrity was examined. The difference between patients and controls was examined using Student's t-test and between patients with either homozygous or heterozygous mutations by Mann-Whitney U test, both at a threshold of 0.05. Increased mean diffusivity throughout the brain can be noticed in the patients, together with a compromised white matter tracts integrity. The most severely affected cortical regions are in the occipital lobe. Decreased functional connectivity was from the temporal and occipital lobes to the hippocampus and parahippocampus. In contrast, connectivity from thalamus was enhanced. Diffused cortical atrophy with posterior focal lesions was noticed. We concluded that MRI observed functional changes in the posterior cortical pathways in the patients with Sialidosis. The observation might be related to the cortical blindness due to an altered neural network and a compromised visual pathway in the patients.

  10. Delayed visual maturation: pupillary responses implicate subcortical and cortical visual systems.

    Science.gov (United States)

    Cocker, K D; Moseley, M J; Stirling, H F; Fielder, A R

    1998-03-01

    Vision in very early infancy is probably subserved by subcortical pathways, with many cortical processes only fully emerging by 3 months of age. The improvement of vision in delayed visual maturation (DVM) occurs around this time, and this has given rise to the suggestion that the condition may have a subcortical basis that resolves with the appearance of cortical function. To explore further the role of cortical and subcortical visual systems in DVM we studied the visual development in identical twins, one of whom had type 1b DVM. Two non-invasive methods of investigating visual pathway function were employed: the acuity card procedure (a behavioural response) and luminance and grating pupillometry. While the former reflects both subcortical and cortical function and can be detected at birth, pupil responses to gratings reflect cortical activity alone and normally become measurable at 1 month of age. Development of both behavioural and pupillary responses was delayed in DVM, indicating that although the underlying defect is primarily subcortical, secondarily it delays the emergence of cortically mediated responses. The observed rapidity of improvement--over a very few days and within a narrow age range--suggests a discrete rather than a widespread structural abnormality, the improvement of which is closely linked to postmenstrual age.

  11. A Quantitative Electroencephalography Study on Cochlear Implant-Induced Cortical Changes in Single-Sided Deafness with Tinnitus

    Directory of Open Access Journals (Sweden)

    Jae-Jin Song

    2017-05-01

    Full Text Available The mechanism of tinnitus suppression after cochlear implantation (CI in single-sided deafness (SSD is not fully understood. In this regard, by comparing pre- and post-CI quantitative electroencephalography (qEEG, we explored cortical changes relevant to tinnitus improvement. In SSD patients who underwent CI, qEEG data were collected: (1 before CI, (2 6 months post-operatively with CI-on, and (3 30 min after CI-off and source-localized cortical activity/functional connectivity analyses were performed. Compared to the pre-operative baseline, the CI-on condition demonstrated significantly decreased activity in the right auditory- and orbitofrontal cortices (OFC for the delta frequency band as well as decreased connectivity between the auditory cortex/posterior cingulate cortex for the delta/beta2 bands. Meanwhile, compared to the CI-off condition, the CI-on condition displayed decreased activity in the right auditory cortices/OFC for the delta band, and in bilateral auditory cortices, left inferior frontal cortex/OFC for the gamma band. However, qEEG analyses showed no significant differences between the CI-off and baseline conditions. CI induced overall decreased cortical activity and functional connectivity. However, judging from no differences between the CI-off and baseline conditions, CI-induced cortical activity and functional connectivity changes are not by cortical plastic changes, but by dynamic peripheral reafferentation.

  12. Nonlinear transfer of signal and noise correlations in cortical networks.

    Science.gov (United States)

    Lyamzin, Dmitry R; Barnes, Samuel J; Donato, Roberta; Garcia-Lazaro, Jose A; Keck, Tara; Lesica, Nicholas A

    2015-05-27

    Signal and noise correlations, a prominent feature of cortical activity, reflect the structure and function of networks during sensory processing. However, in addition to reflecting network properties, correlations are also shaped by intrinsic neuronal mechanisms. Here we show that spike threshold transforms correlations by creating nonlinear interactions between signal and noise inputs; even when input noise correlation is constant, spiking noise correlation varies with both the strength and correlation of signal inputs. We characterize these effects systematically in vitro in mice and demonstrate their impact on sensory processing in vivo in gerbils. We also find that the effects of nonlinear correlation transfer on cortical responses are stronger in the synchronized state than in the desynchronized state, and show that they can be reproduced and understood in a model with a simple threshold nonlinearity. Since these effects arise from an intrinsic neuronal property, they are likely to be present across sensory systems and, thus, our results are a critical step toward a general understanding of how correlated spiking relates to the structure and function of cortical networks. Copyright © 2015 Lyamzin et al.

  13. The evolution of alexia and simultanagnosia in posterior cortical atrophy.

    Science.gov (United States)

    Mendez, M F; Cherrier, M M

    1998-04-01

    Early alexia and higher visual impairments characterize Posterior cortical atrophy (PCA), a progressive dementing syndrome most often caused by Alzheimer disease. Posterior cortical atrophy is rare, and the nature of the visual impairments in PCA are unclear. The authors observed two patients who had an insidiously progressive reading difficulty characterized by letter-by-letter reading and otherwise intact cognitive functions. Over time, these patients developed "ventral simultanagnosia" with preserved detection of multiple stimuli but inability to interpret whole scenes. Subsequently, they progressed to Balint syndrome with "dorsal simultanagnosia," optic ataxia, and oculomotor apraxia. Structural imaging was normal, but functional imaging revealed posterior cortical dysfunction. On a letter reading task, both patients had a word superiority effect, and on a whole word reading task, they could not read most words with missing or crosshatched letters. An inability to assess whole scenes progressed to an inability to detect more than one stimulus in an array. These findings suggest an evolution of PCA with progressive difficulty in visual integration beginning with letters, progressing to whole scenes, and culminating in Balint syndrome. These changes may reflect an extension of the pathophysiology of PCA from the extrastriate visual cortex to its occipitotemporal and occipitoparietal connections.

  14. A computational model of hemodynamic parameters in cortical capillary networks.

    Science.gov (United States)

    Safaeian, Navid; Sellier, Mathieu; David, Tim

    2011-02-21

    The analysis of hemodynamic parameters and functional reactivity of cerebral capillaries is still controversial. To assess the hemodynamic parameters in the cortical capillary network, a generic model was created using 2D voronoi tessellation in which each edge represents a capillary segment. This method is capable of creating an appropriate generic model of cerebral capillary network relating to each part of the brain cortex because the geometric model is able to vary the capillary density. The modeling presented here is based on morphometric parameters extracted from physiological data of the human cortex. The pertinent hemodynamic parameters were obtained by numerical simulation based on effective blood viscosity as a function of hematocrit and microvessel diameter, phase separation and plasma skimming effects. The hemodynamic parameters of capillary networks with two different densities (consistent with the variation of the morphometric data in the human cortical capillary network) were analyzed. The results show pertinent hemodynamic parameters for each model. The heterogeneity (coefficient variation) and the mean value of hematocrits, flow rates and velocities of the both network models were specified. The distributions of blood flow throughout the both models seem to confirm the hypothesis in which all capillaries in a cortical network are recruited at rest (normal condition). The results also demonstrate a discrepancy of the network resistance between two models, which are derived from the difference in the number density of capillary segments between the models. Copyright © 2010 Elsevier Ltd. All rights reserved.

  15. Cortical geometry as a determinant of brain activity eigenmodes: Neural field analysis

    Science.gov (United States)

    Gabay, Natasha C.; Robinson, P. A.

    2017-09-01

    Perturbation analysis of neural field theory is used to derive eigenmodes of neural activity on a cortical hemisphere, which have previously been calculated numerically and found to be close analogs of spherical harmonics, despite heavy cortical folding. The present perturbation method treats cortical folding as a first-order perturbation from a spherical geometry. The first nine spatial eigenmodes on a population-averaged cortical hemisphere are derived and compared with previous numerical solutions. These eigenmodes contribute most to brain activity patterns such as those seen in electroencephalography and functional magnetic resonance imaging. The eigenvalues of these eigenmodes are found to agree with the previous numerical solutions to within their uncertainties. Also in agreement with the previous numerics, all eigenmodes are found to closely resemble spherical harmonics. The first seven eigenmodes exhibit a one-to-one correspondence with their numerical counterparts, with overlaps that are close to unity. The next two eigenmodes overlap the corresponding pair of numerical eigenmodes, having been rotated within the subspace spanned by that pair, likely due to second-order effects. The spatial orientations of the eigenmodes are found to be fixed by gross cortical shape rather than finer-scale cortical properties, which is consistent with the observed intersubject consistency of functional connectivity patterns. However, the eigenvalues depend more sensitively on finer-scale cortical structure, implying that the eigenfrequencies and consequent dynamical properties of functional connectivity depend more strongly on details of individual cortical folding. Overall, these results imply that well-established tools from perturbation theory and spherical harmonic analysis can be used to calculate the main properties and dynamics of low-order brain eigenmodes.

  16. Task-Modulated Cortical Representations of Natural Sound Source Categories

    DEFF Research Database (Denmark)

    Hjortkjær, Jens; Kassuba, Tanja; Madsen, Kristoffer H.

    2017-01-01

    discriminability. Action categories were more accurately decoded in auditory cortex when subjects identified action information. Conversely, the material of the same sound sources was decoded with higher accuracy in the inferior frontal cortex during material identification. Representational similarity analyses...... indicated that both early and higher-order auditory cortex selectively enhanced spectrotemporal features relevant to the target category. Together, the results indicate a cortical selection mechanism that favors task-relevant information in the processing of nonvocal sound categories.......In everyday sound environments, we recognize sound sources and events by attending to relevant aspects of an acoustic input. Evidence about the cortical mechanisms involved in extracting relevant category information from natural sounds is, however, limited to speech. Here, we used functional MRI...

  17. Evaluation of full cortical allografts in 25 dogs.

    Science.gov (United States)

    Sinibaldi, K R

    1989-06-01

    Twenty-five dogs received 26 cortical allografts from Apr 9, 1976 through Jan 31, 1982. Cortical allografts were used to reconstruct fractures of the femur, humerus, tibia, radius, and ulna. These grafts were used to replace comminuted fragments; to lengthen bones; to correct malunions, delayed unions, and nonunions; and in one case, to replace bone lost to sequestrum formation in an infected fracture site. All fractures were stabilized by use of standard ASIF techniques and dynamic compression plates. Frozen bone allografts were used in all cases. These were harvested aseptically and stored in a household freezer for 3 days to one year before use. Clinically normal function was achieved in 96% of the dogs.

  18. Reversible cortical blindness in a case of hepatic encephalopathy

    Directory of Open Access Journals (Sweden)

    Amlan Kanti Biswas

    2016-01-01

    Full Text Available Hepatic encephalopathy is a frequent and often fatal manifestation of chronic liver disease. The pathogenesis of hepatic encephalopathy is believed to be multifactorial including impaired blood-brain barrier function, imbalance between the excitatory and inhibitory neurotransmitters in cortex, accumulation of various toxic and false neurotransmitters, and lack of nutrients like oxygen and glucose. Signs and symptoms of hepatic encephalopathy varies and commonly ranges from personality changes, disturbed consciousness, sleep pattern alternation, intellectual deterioration, speech disturbances, asterixis to frank coma and even death. Reversible or transient cortical blindness is rare manifestation of hepatic encephalopathy. It may even precede the phase of altered consciousness in such patients. Very few similar cases have been reported worldwide. Hence, we would like to report a case of transient cortical blindness in a patient of hepatic encephalopathy.

  19. Alterações na distribuição de potência cortical em função da consolidação da memória no aprendizado de datilografia Changes in cortical power distribution produced by memory consolidation as a function of a typewriting skill

    Directory of Open Access Journals (Sweden)

    Marlo Cunha

    2004-09-01

    Full Text Available O objetivo do presente estudo foi investigar alterações nos padrões eletroencefalográficos de sujeitos normais e destros durante o aprendizado de uma tarefa motora (datilografia. Estudos têm demonstrado que o córtex cerebral é susceptível a modificações durante a aprendizagem e que alterações nos padrões elétricos corticais ocorrem em função da aquisição de uma habilidade motora e da consolidação da memória. Assim, a atividade elétrica cortical dos sujeitos foi analisada antes e depois da prática motora. Os dados foram captados pelo "Braintech" 3000 e analisados pelo programa "Neurometrics". Para a análise estatística, variáveis comportamentais tais como tempo e erro, foram analisadas através do teste ANOVA "one-way" (diferenças entre blocos. Em seguida, foi utilizado um Teste-t pareado para os pares de eletrodos CZ-C3/CZ-C4, nas bandas de freqüência teta e alfa. Os resultados principais demonstraram mudança na performance através das variáveis comportamentais "tempo" e "número de erros". Concomitantemente, não foram observadas alterações na variável neurofisiológica "Potência Absoluta" na banda teta. Em contrapartida, houve um aumento significativo na banda alfa em áreas centrais (CZ-C3/CZ-C4. Tais resultados sugerem uma adaptação do córtex sensório-motor em função do treinamento de datilografia.The present study aimed to investigate alterations in EEG patterns in normal, right-handed individuals, during the process of learning a specific motor skill (typewriting. Recent studies have shown that the cerebral cortex is susceptible to several changes during a learning process and that alterations in the brain's electrical patterns take place as a result of the acquisition of a motor skill and memory consolidation. In this context, subjects' brain electrical activity was analyzed before and after the motor task. EEG data were collected by a Braintech 3000 and analyzed by Neurometrics. For the

  20. Encoding Cortical Dynamics in Sparse Features

    Directory of Open Access Journals (Sweden)

    Sheraz eKhan

    2014-05-01

    Full Text Available Distributed cortical solutions of magnetoencephalography (MEG and electroencephalography (EEG exhibit complex spatial and temporal dynamics. The extraction of patterns of interest and dynamic features from these cortical signals has so far relied on the expertise of investigators. There is a definite need in both clinical and neuroscience research for a method that will extract critical features from high-dimensional neuroimaging data in an automatic fashion. We have previously demonstrated the use of optical flow techniques for evaluating the kinematic properties of motion field projected on non-flat manifolds like in a cortical surface. We have further extended this framework to automatically detect features in the optical flow vector field by using the modified and extended 2-Riemannian Helmholtz Hodge Decomposition (HHD. Here, we applied these mathematical models on simulation and MEG data recorded from a healthy individual during a somatosensory experiment and an epilepsy pediatric patient during sleep. We tested whether our technique can automatically extract salient dynamical features of cortical activity. Simulation results indicated that we can precisely reproduce the simulated cortical dynamics with HHD; encode them in sparse features and represent the propagation of brain activity between distinct cortical areas. Using HHD, we decoded the somatosensory N20 component into two HHD features and represented the dynamics of brain activity as a traveling source between two primary somatosensory regions. In the epilepsy patient, we displayed the propagation of the epileptiform activity around the margins of a brain lesion. Our findings indicate that HHD measures computed from cortical dynamics can: (i quantitatively access the cortical dynamics in both healthy and disease brain in terms of sparse features and dynamic brain activity propagation between distinct cortical areas, and (ii facilitate a reproducible, automated analysis of MEG

  1. Rapid Identification of Cortical Motor Areas in Rodents by High-Frequency Automatic Cortical Stimulation and Novel Motor Threshold Algorithm.

    Science.gov (United States)

    Takemi, Mitsuaki; Castagnola, Elisa; Ansaldo, Alberto; Ricci, Davide; Fadiga, Luciano; Taoka, Miki; Iriki, Atsushi; Ushiba, Junichi

    2017-01-01

    Cortical stimulation mapping is a valuable tool to test the functional organization of the motor cortex in both basic neurophysiology (e.g., elucidating the process of motor plasticity) and clinical practice (e.g., before resecting brain tumors involving the motor cortex). However, compilation of motor maps based on the motor threshold (MT) requires a large number of cortical stimulations and is therefore time consuming. Shortening the time for mapping may reduce stress on the subjects and unveil short-term plasticity mechanisms. In this study, we aimed to establish a cortical stimulation mapping procedure in which the time needed to identify a motor area is reduced to the order of minutes without compromising reliability. We developed an automatic motor mapping system that applies epidural cortical surface stimulations (CSSs) through one-by-one of 32 micro-electrocorticographic electrodes while examining the muscles represented in a cortical region. The next stimulus intensity was selected according to previously evoked electromyographic responses in a closed-loop fashion. CSS was repeated at 4 Hz and electromyographic responses were submitted to a newly proposed algorithm estimating the MT with smaller number of stimuli with respect to traditional approaches. The results showed that in all tested rats (n = 12) the motor area maps identified by our novel mapping procedure (novel MT algorithm and 4-Hz CSS) significantly correlated with the maps achieved by the conventional MT algorithm with 1-Hz CSS. The reliability of the both mapping methods was very high (intraclass correlation coefficients ≧0.8), while the time needed for the mapping was one-twelfth shorter with the novel method. Furthermore, the motor maps assessed by intracortical microstimulation and the novel CSS mapping procedure in two rats were compared and were also significantly correlated. Our novel mapping procedure that determined a cortical motor area within a few minutes could help to study the

  2. Tibial cortical lesions: A multimodality pictorial review

    Energy Technology Data Exchange (ETDEWEB)

    Tyler, P.A., E-mail: philippa.tyler@rnoh.nhs.uk [Department of Radiology, Royal National Orthopaedic Hospital, Brockley Hill, Stanmore HA7 4LP (United Kingdom); Mohaghegh, P., E-mail: pegah1000@gmail.com [Department of Radiology, Royal National Orthopaedic Hospital, Brockley Hill, Stanmore HA7 4LP (United Kingdom); Foley, J., E-mail: jfoley1@nhs.net [Department of Radiology, Glasgow Royal Infirmary, 16 Alexandra Parade, Glasgow G31 2ES (United Kingdom); Isaac, A., E-mail: amandaisaac@doctors.org.uk [Department of Radiology, King' s College Hospital, Denmark Hill, London SE5 9RS (United Kingdom); Zavareh, A., E-mail: ali.zavareh@gmail.com [Department of Radiology, North Bristol NHS Trust, Frenchay, Bristol BS16 1LE (United Kingdom); Thorning, C., E-mail: cthorning@doctors.org.uk [Department of Radiology, East Surrey Hospital, Canada Avenue, Redhill, Surrey RH1 5RH (United Kingdom); Kirwadi, A., E-mail: anandkirwadi@gmail.com [Department of Radiology, Manchester Royal Infirmary, Oxford Road, Manchester M13 9WL (United Kingdom); Pressney, I., E-mail: ipressney@hotmail.com [Department of Radiology, Royal National Orthopaedic Hospital, Brockley Hill, Stanmore HA7 4LP (United Kingdom); Amary, F., E-mail: fernanda.amary@rnoh.nhs.uk [Department of Histopathology, Royal National Orthopaedic Hospital, Brockley Hill, Stanmore HA7 4LP (United Kingdom); Rajeswaran, G., E-mail: grajeswaran@gmail.com [Department of Radiology, Chelsea and Westminster Hospital, 369 Fulham Road, London SW10 9NH (United Kingdom)

    2015-01-15

    Highlights: • Multimodality imaging plays an important role in the investigation and diagnosis of shin pain. • We review the multimodality imaging findings of common cortically based tibial lesions. • We also describe the rarer pathologies of tibial cortical lesions. - Abstract: Shin pain is a common complaint, particularly in young and active patients, with a wide range of potential diagnoses and resulting implications. We review the natural history and multimodality imaging findings of the more common causes of cortically-based tibial lesions, as well as the rarer pathologies less frequently encountered in a general radiology department.

  3. Cortical gyrification in autistic and Asperger disorders: a preliminary magnetic resonance imaging study.

    Science.gov (United States)

    Jou, Roger J; Minshew, Nancy J; Keshavan, Matcheri S; Hardan, Antonio Y

    2010-12-01

    The validity of Asperger disorder as a distinct syndrome from autism is unclear partly because of the paucity of differentiating neurobiological evidence. Frontal lobe cortical folding between these disorders was compared using the gyrification index. Twenty-three boys underwent structural magnetic resonance imaging: 6 with high-functioning autism, 9 with Asperger disorder, and 8 controls. Using the first coronal slice anterior to the corpus callosum, total and outer cortical contours were traced to calculate the gyrification index. This index was also calculated for superior and inferior regions to examine dorsolateral prefrontal and orbitofrontal cortices, respectively. Analysis of variance revealed differences in the left inferior gyrification index, which was higher in the autism group compared with Asperger and control groups. There were no differences in age, intelligence quotient, and brain volume. These preliminary findings suggest that cortical folding may be abnormally high in the frontal lobe in autism but not Asperger disorder, suggesting distinct frontal lobe neuropathology.

  4. Sensory experience regulates cortical inhibition by inducing IGF1 in VIP neurons.

    Science.gov (United States)

    Mardinly, A R; Spiegel, I; Patrizi, A; Centofante, E; Bazinet, J E; Tzeng, C P; Mandel-Brehm, C; Harmin, D A; Adesnik, H; Fagiolini, M; Greenberg, M E

    2016-03-17

    Inhibitory neurons regulate the adaptation of neural circuits to sensory experience, but the molecular mechanisms by which experience controls the connectivity between different types of inhibitory neuron to regulate cortical plasticity are largely unknown. Here we show that exposure of dark-housed mice to light induces a gene program in cortical vasoactive intestinal peptide (VIP)-expressing neurons that is markedly distinct from that induced in excitatory neurons and other subtypes of inhibitory neuron. We identify Igf1 as one of several activity-regulated genes that are specific to VIP neurons, and demonstrate that IGF1 functions cell-autonomously in VIP neurons to increase inhibitory synaptic input onto these neurons. Our findings further suggest that in cortical VIP neurons, experience-dependent gene transcription regulates visual acuity by activating the expression of IGF1, thus promoting the inhibition of disinhibitory neurons and affecting inhibition onto cortical pyramidal neurons.

  5. Spatial Heterogeneity of Cortical Excitability in Migraine Revealed by Multifrequency Neuromagnetic Signals.

    Science.gov (United States)

    Xiang, Jing; Leiken, Kimberly; Degrauw, Xinyao; Kay, Benjamin; Fujiwara, Hisako; Rose, Douglas F; Allen, Janelle R; Kacperski, Joanne E; O'Brien, Hope L; Kabbouche, Marielle A; Powers, Scott W; Hershey, Andrew D

    2016-06-01

    To investigate the spatial heterogeneity of cortical excitability in adolescents with migraine, magnetoencephalography (MEG) recordings at a sampling rate of 6,000 Hz were obtained from 35 adolescents with an acute migraine and 35 age- and sex-matched healthy control participants during an auditory-motor task. Neuromagnetic activation from low- to high-frequency ranges (5-1,000 Hz) was measured at sensor and source levels. The heterogeneity of cortical excitability was quantified within each functional modality (auditory vs motor) and hemispherical lateralization. MEG data showed that high-frequency, not low-frequency neuromagnetic signals, showed heterogeneous cortical activation in migraine subjects compared with control participants (P signals in a frequency range of 5 to 1,000 Hz. The characteristics of the location and degree of cortical excitability may be critical for spatially targeted treatment for migraine. Copyright © 2016 American Pain Society. Published by Elsevier Inc. All rights reserved.

  6. Focal cortical dysplasia and epilepsy surgery.

    Science.gov (United States)

    Lee, Sang Kun; Kim, Dong-Wook

    2013-12-01

    Focal cortical dysplasia (FCD) is the most commonly encountered developmental malformation that causes refractory epilepsy. With advances in neuroimaging techniques, in particular MRI, recent studies have revealed a higher prevalence of FCD than previously estimated and have improved the preoperative identification and classification of these abnormalities. However, MRI frequently does not show any abnormalities in patients with pathologically proven FCD. In this situation, functional neuroimaing such as FDG-PET and ictal SPECT can be helpful. FCD is thought to be intrinsically epileptogenic, because the dysplastic tissues contain aberrant neural networks that are highly susceptible to abnormal excitation. The response to the medical treatment of epilepsy has been documented as consistently poor. Therefore, surgical resection has been an important alternative treatment for patients with intractable epilepsy related to FCD. Incomplete resection of FCD has been consistently known to be a poor prognostic factor. However, the complete removal of FCD is often difficult because the demarcation of the lesion is frequently poor, and dysplastic tissues tend to be more extensive than is apparent on MRI. Evidence indicates that even patients with MRI abnormalities who have resective epilepsy surgery for FCD have worse surgical outcomes than those of patients who have surgery for other focal lesional epilepsy syndromes. Careful planning of evelauation using intracranial electrodes is necessary for successful epilepsy surgery.

  7. Spatiotemporal dynamics of early cortical gesture processing.

    Science.gov (United States)

    Möhring, Nicole; Shen, Christina; Neuhaus, Andres H

    2014-10-01

    Gesture processing has been consistently shown to be associated with activation of the inferior parietal lobe (IPL); however, little is known about the integration of IPL activation into the temporal dynamics of early sensory areas. Using a temporally graded repetition suppression paradigm, we examined the activation and time course of brain areas involved in hand gesture processing. We recorded event-related potentials in response to stimulus pairs of static hand images forming gestures of the popular rock-paper-scissors game and estimated their neuronal generators. We identified two main components associated with adaptive patterns related to stimulus repetition. The N190 component elicited at temporo-parietal sites adapted to repetitions of the same gesture and was associated with right-hemispheric extrastriate body area activation. A later component at parieto-occipital sites demonstrated temporally graded adaptation effects for all gestures with a left-hemispheric dominance. Source localization revealed concurrent activations of the right extrastriate body area, fusiform gyri bilaterally, and the left IPL at about 250 ms. The adaptation pattern derived from the graded repetition suppression paradigm demonstrates the functional sensitivity of these sources to gesture processing. Given the literature on IPL contribution to imitation, action recognition, and action execution, IPL activation at about 250 ms may represent the access into specific cognitive routes for gesture processing and may thus be involved in integrating sensory information from cortical body areas into subsequent visuo-motor transformation processes. Copyright © 2014 Elsevier Inc. All rights reserved.

  8. Facilitating text reading in posterior cortical atrophy.

    Science.gov (United States)

    Yong, Keir X X; Rajdev, Kishan; Shakespeare, Timothy J; Leff, Alexander P; Crutch, Sebastian J

    2015-07-28

    We report (1) the quantitative investigation of text reading in posterior cortical atrophy (PCA), and (2) the effects of 2 novel software-based reading aids that result in dramatic improvements in the reading ability of patients with PCA. Reading performance, eye movements, and fixations were assessed in patients with PCA and typical Alzheimer disease and in healthy controls (experiment 1). Two reading aids (single- and double-word) were evaluated based on the notion that reducing the spatial and oculomotor demands of text reading might support reading in PCA (experiment 2). Mean reading accuracy in patients with PCA was significantly worse (57%) compared with both patients with typical Alzheimer disease (98%) and healthy controls (99%); spatial aspects of passages were the primary determinants of text reading ability in PCA. Both aids led to considerable gains in reading accuracy (PCA mean reading accuracy: single-word reading aid = 96%; individual patient improvement range: 6%-270%) and self-rated measures of reading. Data suggest a greater efficiency of fixations and eye movements under the single-word reading aid in patients with PCA. These findings demonstrate how neurologic characterization of a neurodegenerative syndrome (PCA) and detailed cognitive analysis of an important everyday skill (reading) can combine to yield aids capable of supporting important everyday functional abilities. This study provides Class III evidence that for patients with PCA, 2 software-based reading aids (single-word and double-word) improve reading accuracy. © 2015 American Academy of Neurology.

  9. Childhood cognitive ability accounts for associations between cognitive ability and brain cortical thickness in old age.

    Science.gov (United States)

    Karama, S; Bastin, M E; Murray, C; Royle, N A; Penke, L; Muñoz Maniega, S; Gow, A J; Corley, J; Valdés Hernández, M del C; Lewis, J D; Rousseau, M-É; Lepage, C; Fonov, V; Collins, D L; Booth, T; Rioux, P; Sherif, T; Adalat, R; Starr, J M; Evans, A C; Wardlaw, J M; Deary, I J

    2014-05-01

    Associations between brain cortical tissue volume and cognitive function in old age are frequently interpreted as suggesting that preservation of cortical tissue is the foundation of successful cognitive aging. However, this association could also, in part, reflect a lifelong association between cognitive ability and cortical tissue. We analyzed data on 588 subjects from the Lothian Birth Cohort 1936 who had intelligence quotient (IQ) scores from the same cognitive test available at both 11 and 70 years of age as well as high-resolution brain magnetic resonance imaging data obtained at approximately 73 years of age. Cortical thickness was estimated at 81 924 sampling points across the cortex for each subject using an automated pipeline. Multiple regression was used to assess associations between cortical thickness and the IQ measures at 11 and 70 years. Childhood IQ accounted for more than two-third of the association between IQ at 70 years and cortical thickness measured at age 73 years. This warns against ascribing a causal interpretation to the association between cognitive ability and cortical tissue in old age based on assumptions about, and exclusive reference to, the aging process and any associated disease. Without early-life measures of cognitive ability, it would have been tempting to conclude that preservation of cortical thickness in old age is a foundation for successful cognitive aging when, instead, it is a lifelong association. This being said, results should not be construed as meaning that all studies on aging require direct measures of childhood IQ, but as suggesting that proxy measures of prior cognitive function can be useful to take into consideration.

  10. VAGUS NERVE STIMULATION INHIBITS CORTICAL SPREADING DEPRESSION

    OpenAIRE

    Chen, Shih-Pin; Ay, Ilknur; de Morais, Andreia Lopes; Qin, Tao; Zheng,Yi; Sadhegian, Homa; Oka, Fumiaki; Simon, Bruce; Eikermann-Haerter, Katharina; Ayata, Cenk

    2016-01-01

    Vagus nerve stimulation has recently been reported to improve symptoms of migraine. Cortical spreading depression is the electrophysiological event underlying migraine aura, and a trigger for headache. We tested whether vagus nerve stimulation inhibits cortical spreading depression to explain its anti-migraine effect. Vagus nerve stimulation was delivered either non-invasively through the skin or directly by electrodes placed around the vagus nerve unilaterally. Systemic physiology was monito...

  11. Elastic Properties of Chimpanzee Craniofacial Cortical Bone.

    Science.gov (United States)

    Gharpure, Poorva; Kontogiorgos, Elias D; Opperman, Lynne A; Ross, Callum F; Strait, David S; Smith, Amanda; Pryor, Leslie C; Wang, Qian; Dechow, Paul C

    2016-12-01

    Relatively few assessments of cranial biomechanics formally take into account variation in the material properties of cranial cortical bone. Our aim was to characterize the elastic properties of chimpanzee craniofacial cortical bone and compare these to the elastic properties of dentate human craniofacial cortical bone. From seven cranial regions, 27 cylindrical samples were harvested from each of five chimpanzee crania. Assuming orthotropy, axes of maximum stiffness in the plane of the cortical plate were derived using modified equations of Hooke's law in a Mathcad program. Consistent orientations among individuals were observed in the zygomatic arch and alveolus. The density of cortical bone showed significant regional variation (P  E2  > E1 . Shear moduli were significantly different among regions (P < 0.001). The pattern by which chimpanzee cranial cortical bone varies in elastic properties resembled that seen in humans, perhaps suggesting that the elastic properties of craniofacial bone in fossil hominins can be estimated with at least some degree of confidence. Anat Rec, 299:1718-1733, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  12. Task-Modulated Cortical Representations of Natural Sound Source Categories.

    Science.gov (United States)

    Hjortkjær, Jens; Kassuba, Tanja; Madsen, Kristoffer H; Skov, Martin; Siebner, Hartwig R

    2017-10-23

    In everyday sound environments, we recognize sound sources and events by attending to relevant aspects of an acoustic input. Evidence about the cortical mechanisms involved in extracting relevant category information from natural sounds is, however, limited to speech. Here, we used functional MRI to measure cortical response patterns while human listeners categorized real-world sounds created by objects of different solid materials (glass, metal, wood) manipulated by different sound-producing actions (striking, rattling, dropping). In different sessions, subjects had to identify either material or action categories in the same sound stimuli. The sound-producing action and the material of the sound source could be decoded from multivoxel activity patterns in auditory cortex, including Heschl's gyrus and planum temporale. Importantly, decoding success depended on task relevance and category discriminability. Action categories were more accurately decoded in auditory cortex when subjects identified action information. Conversely, the material of the same sound sources was decoded with higher accuracy in the inferior frontal cortex during material identification. Representational similarity analyses indicated that both early and higher-order auditory cortex selectively enhanced spectrotemporal features relevant to the target category. Together, the results indicate a cortical selection mechanism that favors task-relevant information in the processing of nonvocal sound categories. © The Author 2017. Published by Oxford University Press.

  13. The characteristics of cortical glucose metabolism in amblyopia

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Ji Young [College of Medicine, Seoul National Univ., Seoul (Korea, Republic of); Lee, Dong Soo; Chung, June Key; Shin, Seung Ai; Lee, Myung Chul [College of Medicine, Ewha Womans Univ., Seoul (Korea, Republic of)

    2000-07-01

    Cortical metabolism of amblyopia patients was investigated with F-18-FDG PET and Statistical Parametric Mapping (SPM) and quantificiation based on volume of interest (VOI) by statistical probabilistic anatomical map (SPAM). In 9 amblyopic patients (12{+-}7 years ) and 20 normal subjects (23{+-}2 years), F-18-FDG PET scans were peformed in amblyopic patients after amblyopic eye or sound eye was patch-closed during PET studies. SPM was done with SPM96. By multiplying SPAM to FDG images, counts of 98 VOI's were calculated and compared with 3 S. D. range of those of normal subjects. On SPM, cortical metabolism decreased (p<0.05) in occipital lobe (Ba 17, 18, 19), superior partietal lobe (Ba 7), and inferior temporal lobe (BA 37, 20). FDG uptake of gyri of occuipital lobe was decreased in 2 and increased in 2, and was normal in the other 5. FDG uptake of gyri of parietal, frontal, and temporal lobes were decreased in FDG uptake on these VOIs. We conclude that cortical metabolism in occipital lobe and extraoccipital lobes was variable but was consistent regardless of visual input during PET studies in amblyopic patients. SPM and quantification of functional images using SPAM could reveal subtle differences or changes according to visual input. The significance of metabolic changes of extraoccipital lobes should be studies further.

  14. Cortical mechanisms for the segregation and representation of acoustic textures.

    Science.gov (United States)

    Overath, Tobias; Kumar, Sukhbinder; Stewart, Lauren; von Kriegstein, Katharina; Cusack, Rhodri; Rees, Adrian; Griffiths, Timothy D

    2010-02-10

    Auditory object analysis requires two fundamental perceptual processes: the definition of the boundaries between objects, and the abstraction and maintenance of an object's characteristic features. Although it is intuitive to assume that the detection of the discontinuities at an object's boundaries precedes the subsequent precise representation of the object, the specific underlying cortical mechanisms for segregating and representing auditory objects within the auditory scene are unknown. We investigated the cortical bases of these two processes for one type of auditory object, an "acoustic texture," composed of multiple frequency-modulated ramps. In these stimuli, we independently manipulated the statistical rules governing (1) the frequency-time space within individual textures (comprising ramps with a given spectrotemporal coherence) and (2) the boundaries between textures (adjacent textures with different spectrotemporal coherences). Using functional magnetic resonance imaging, we show mechanisms defining boundaries between textures with different coherences in primary and association auditory cortices, whereas texture coherence is represented only in association cortex. Furthermore, participants' superior detection of boundaries across which texture coherence increased (as opposed to decreased) was reflected in a greater neural response in auditory association cortex at these boundaries. The results suggest a hierarchical mechanism for processing acoustic textures that is relevant to auditory object analysis: boundaries between objects are first detected as a change in statistical rules over frequency-time space, before a representation that corresponds to the characteristics of the perceived object is formed.

  15. Migraine with brainstem aura: Why not a cortical origin?

    Science.gov (United States)

    Demarquay, Geneviève; Ducros, Anne; Montavont, Alexandra; Mauguiere, François

    2017-01-01

    Background Migraine with brainstem aura is defined as a migraine with aura including at least two of the following symptoms: dysarthria, vertigo, tinnitus, hypacusis, diplopia, ataxia and/or decreased level of consciousness. Aim The aim of this study is to review data coming from clinical observations and functional mapping that support the role of the cerebral cortex in the initiation of brainstem aura symptoms. Results Vertigo can result from a vestibular cortex dysfunction, while tinnitus and hypacusis can originate within the auditory cortex. Diplopia can reflect a parieto-occipital involvement. Dysarthria can be caused by dysfunctions located in precentral gyri. Ataxia can reflect abnormal processing of vestibular, sensory, or visual inputs by the parietal lobe. Alteration of consciousness can be caused by abnormal neural activation within specific consciousness networks that include prefrontal and posterior parietal cortices. Conclusion Any symptom of so-called brainstem aura can originate within the cortex. Based on these data, we suggest that brainstem aura could have a cortical origin. This hypothesis would explain the co-occurrence of typical and brainstem aura during attacks and would fit with the theory of cortical spreading depression. We propose that migraine with brainstem aura should be classified as a typical migraine aura.

  16. Discriminant analysis of multiple cortical changes in mild cognitive impairment

    Science.gov (United States)

    Wu, Congling; Guo, Shengwen; Lai, Chunren; Wu, Yupeng; Zhao, Di; Jiang, Xingjun

    2017-02-01

    To reveal the differences in brain structures and morphological changes between the mild cognitive impairment (MCI) and the normal control (NC), analyze and predict the risk of MCI conversion. First, the baseline and 2-year longitudinal follow-up magnetic resonance (MR) images of 73 NC, 46 patients with stable MCI (sMCI) and 40 patients with converted MCI (cMCI) were selected. Second, the FreeSurfer was used to extract the cortical features, including the cortical thickness, surface area, gray matter volume and mean curvature. Third, the support vector machine-recursive feature elimination method (SVM-RFE) were adopted to determine salient features for effective discrimination. Finally, the distribution and importance of essential brain regions were described. The experimental results showed that the cortical thickness and gray matter volume exhibited prominent capability in discrimination, and surface area and mean curvature behaved relatively weak. Furthermore, the combination of different morphological features, especially the baseline combined with the longitudinal changes, can be used to evidently improve the performance of classification. In addition, brain regions with high weights predominately located in the temporal lobe and the frontal lobe, which were relative to emotional control and memory functions. It suggests that there were significant different patterns in the brain structure and changes between the compared group, which could not only be effectively applied for classification, but also be used to evaluate and predict the conversion of the patients with MCI.

  17. On cortical coding of vocal communication sounds in primates

    Science.gov (United States)

    Wang, Xiaoqin

    2000-10-01

    Understanding how the brain processes vocal communication sounds is one of the most challenging problems in neuroscience. Our understanding of how the cortex accomplishes this unique task should greatly facilitate our understanding of cortical mechanisms in general. Perception of species-specific communication sounds is an important aspect of the auditory behavior of many animal species and is crucial for their social interactions, reproductive success, and survival. The principles of neural representations of these behaviorally important sounds in the cerebral cortex have direct implications for the neural mechanisms underlying human speech perception. Our progress in this area has been relatively slow, compared with our understanding of other auditory functions such as echolocation and sound localization. This article discusses previous and current studies in this field, with emphasis on nonhuman primates, and proposes a conceptual platform to further our exploration of this frontier. It is argued that the prerequisite condition for understanding cortical mechanisms underlying communication sound perception and production is an appropriate animal model. Three issues are central to this work: (i) neural encoding of statistical structure of communication sounds, (ii) the role of behavioral relevance in shaping cortical representations, and (iii) sensory-motor interactions between vocal production and perception systems.

  18. Towards a mathematical theory of cortical micro-circuits.

    Directory of Open Access Journals (Sweden)

    Dileep George

    2009-10-01

    Full Text Available The theoretical setting of hierarchical Bayesian inference is gaining acceptance as a framework for understanding cortical computation. In this paper, we describe how Bayesian belief propagation in a spatio-temporal hierarchical model, called Hierarchical Temporal Memory (HTM, can lead to a mathematical model for cortical circuits. An HTM node is abstracted using a coincidence detector and a mixture of Markov chains. Bayesian belief propagation equations for such an HTM node define a set of functional constraints for a neuronal implementation. Anatomical data provide a contrasting set of organizational constraints. The combination of these two constraints suggests a theoretically derived interpretation for many anatomical and physiological features and predicts several others. We describe the pattern recognition capabilities of HTM networks and demonstrate the application of the derived circuits for modeling the subjective contour effect. We also discuss how the theory and the circuit can be extended to explain cortical features that are not explained by the current model and describe testable predictions that can be derived from the model.

  19. Regulation of cerebral cortical neurogenesis by the Pax6 transcription factor.

    Science.gov (United States)

    Manuel, Martine N; Mi, Da; Mason, John O; Price, David J

    2015-01-01

    Understanding brain development remains a major challenge at the heart of understanding what makes us human. The neocortex, in evolutionary terms the newest part of the cerebral cortex, is the seat of higher cognitive functions. Its normal development requires the production, positioning, and appropriate interconnection of very large numbers of both excitatory and inhibitory neurons. Pax6 is one of a relatively small group of transcription factors that exert high-level control of cortical development, and whose mutation or deletion from developing embryos causes major brain defects and a wide range of neurodevelopmental disorders. Pax6 is very highly conserved between primate and non-primate species, is expressed in a gradient throughout the developing cortex and is essential for normal corticogenesis. Our understanding of Pax6's functions and the cellular processes that it regulates during mammalian cortical development has significantly advanced in the last decade, owing to the combined application of genetic and biochemical analyses. Here, we review the functional importance of Pax6 in regulating cortical progenitor proliferation, neurogenesis, and formation of cortical layers and highlight important differences between rodents and primates. We also review the pathological effects of PAX6 mutations in human neurodevelopmental disorders. We discuss some aspects of Pax6's molecular actions including its own complex transcriptional regulation, the distinct molecular functions of its splice variants and some of Pax6's known direct targets which mediate its actions during cortical development.

  20. MEMORIA OPERATIVA Y CIRCUITOS CORTICALES Working memory and cortical pathways

    Directory of Open Access Journals (Sweden)

    Gabriel Arteaga Díaz

    2006-10-01

    Full Text Available En el presente artículo se expone una revisión del concepto “memoria operativa”, teniendo en cuenta dos aproximaciones principales. Por una parte la psicología cognitiva, particularmente en el campo de la memoria y el aprendizaje; mientras que por otra parte, se presentan algunos aspectos del aporte de las neurociencias, tanto en lo relacionado con fenómenos clínicos como experimentales. Se hace referencia al síndrome prefrontal desde una perspectiva histórica, se consideran igualmente algunos estudios electrofi­siológicos, de imagen funcional, así como los relacionados con ablaciones corticales. Se presenta al final, un modelo de “circuitería” asociada con el proceso de la memoria operativa, en el cual se consideran cinco circuitos básicos: tanto los que se establecen entre regiones corticales, como entre estas y estructuras subcorticales.This paper presents a review on the concept of “Working memory” from two main approaches. On the one hand the cognitive psychology, particularly in the learning and memory fields, while on the other hand it is presented the perspective from neuroscience data: clinical and experimental. It is referenced the prefrontal syndrome from a historical point of view, additionally some electrophysiological, functional imaging, and cortical ablations works are summarized. At the end of the document it is also introduced, a model of the cortical circuitry concerned with working memory processing; five circuits are considered: cortico-cortical as well as cortico-sub cortical loops are depicted.

  1. Cortical modulation of short-latency TMS-evoked potentials

    Directory of Open Access Journals (Sweden)

    Domenica eVeniero

    2013-01-01

    Full Text Available Transcranial magnetic stimulation - electroencephalogram (TMS-EEG co-registration offers the opportunity to test reactivity of brain areas across distinct conditions through TMS-evoked potentials (TEPs. Several TEPs have been described, their functional meaning being largely unknown. In particular, short-latency potentials peaking at 5 (P5 and 8 (N8 ms after the TMS pulse have been recently described, but because of their huge amplitude, the problem of whether their origin is cortical or not has been opened. To gain information about these components, we employed a protocol that modulates primary motor cortex excitability (MI through an exclusively cortical phenomena: low frequency stimulation of premotor area (PMC. TMS was applied simultaneously with EEG recording from 70 electrodes. Amplitude of TEPs evoked by 200 single-pulses TMS delivered over MI at 110% of resting motor threshold was measured before and after applying 900 TMS conditioning stimuli to left premotor cortex with 1 Hz repetition rate. Single subject analyses showed reduction in TEPs amplitude after PMC conditioning in a sample of participants and increase in TEPs amplitude in two subjects. No effects were found on corticospinal excitability as recorded by motor evoked potentials (MEPs. Furthermore, correlation analysis showed an inverse relation between the effects of the conditioning protocol on P5-N8 complex amplitude and MEPs amplitude. Because the effects of the used protocol have been ascribed to a cortical interaction between premotor area and MI, we suggest that despite the sign of P5-N8 amplitude modulation is not consistent across participant, this modulation could indicate, at least in part, their cortical origin. We conclude that with an accurate experimental procedure early-latency components can be used to evaluate the reactivity of the stimulated cortex.

  2. Mapping human cortical areas in vivo based on myelin content as revealed by T1- and T2-weighted MRI.

    Science.gov (United States)

    Glasser, Matthew F; Van Essen, David C

    2011-08-10

    Noninvasively mapping the layout of cortical areas in humans is a continuing challenge for neuroscience. We present a new method of mapping cortical areas based on myelin content as revealed by T1-weighted (T1w) and T2-weighted (T2w) MRI. The method is generalizable across different 3T scanners and pulse sequences. We use the ratio of T1w/T2w image intensities to eliminate the MR-related image intensity bias and enhance the contrast to noise ratio for myelin. Data from each subject were mapped to the cortical surface and aligned across individuals using surface-based registration. The spatial gradient of the group average myelin map provides an observer-independent measure of sharp transitions in myelin content across the surface--i.e., putative cortical areal borders. We found excellent agreement between the gradients of the myelin maps and the gradients of published probabilistic cytoarchitectonically defined cortical areas that were registered to the same surface-based atlas. For other cortical regions, we used published anatomical and functional inf