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  1. Reorganization of human motor cortex after hand replantation.

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    Röricht, S; Machetanz, J; Irlbacher, K; Niehaus, L; Biemer, E; Meyer, B U

    2001-08-01

    In 10 patients, reorganizational changes of the motor cortex contralateral to a replanted hand (MCreplant) were studied one to 14 years after complete traumatic amputation and consecutive successful replantation of the hand. The organizational state of MCreplant was assessed for the deafferentated and peripherally deefferentated hand-associated motor cortex and the adjacent motor representation of the proximal arm. For this, response maps were established for the first dorsal interosseus and biceps brachii muscle using focal transcranial magnetic stimulation (TMS) on a skull surface grid. Characteristics of the maps were center of gravity (COG), number of effective stimulation sites, amplitude sum, and amplitudes and response threshold at the optimal stimulation point. The COG is defined by the spatial distribution of response amplitudes on the map and lies over the cortex region with the most excitable corticospinal neurones supplying the recorded muscle. The COG of the biceps map in MCreplant was shifted laterally by 9.8 +/- 3.6 mm (range 5.0-15.7 mm). The extension of the biceps map in MCreplant was increased and the responses were enlarged and had lowered thresholds. For the muscles of the replanted hand, the pattern of reorganization was different: Response amplitudes were enlarged but thresholds, COG, and area of the cortical response map were normal. The different reorganizational phenomena observed for the motor cortical areas supplying the replanted hand and the biceps brachii of the same arm may be influenced by a different extent of deafferentation and by their different role in hand motor control.

  2. Extrastriate visual cortex reorganizes despite sequential bilateral occipital stroke: implications for vision recovery

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    Amy eBrodtmann

    2015-04-01

    Full Text Available The extent of visual cortex reorganization following injury remains controversial. We report serial functional magnetic resonance imaging (fMRI data from a patient with sequential posterior circulation strokes occurring three weeks apart, compared with data from an age-matched healthy control subject. At 8 days following a left occipital stroke, contralesional visual cortical activation was within expected striate and extrastriate sites, comparable to that seen in controls. Despite a further infarct in the right (previously unaffected hemisphere, there was evolution of visual cortical reorganization progressed. In this patient, there was evidence of utilization of peri-infarct sites (right-sided and recruitment of new activation sites in extrastriate cortices, including in the lateral middle and inferior temporal lobes. The changes over time corresponded topographically with the patient’s lesion site and its connections. Reorganization of the surviving visual cortex was demonstrated 8 days after the first stroke. Ongoing reorganization in extant cortex was demonstrated at the 6 month scan. We present a summary of mechanisms of recovery following stroke relevant to the visual system. We conclude that mature primary visual cortex displays considerable plasticity and capacity to reorganize, associated with evolution of visual field deficits. We discuss these findings and their implications for therapy within the context of current concepts in visual compensatory and restorative therapies.

  3. Extrastriate visual cortex reorganizes despite sequential bilateral occipital stroke: implications for vision recovery.

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    Brodtmann, Amy; Puce, Aina; Darby, David; Donnan, Geoffrey

    2015-01-01

    The extent of visual cortex reorganization following injury remains controversial. We report serial functional magnetic resonance imaging (fMRI) data from a patient with sequential posterior circulation strokes occurring 3 weeks apart, compared with data from an age-matched healthy control subject. At 8 days following a left occipital stroke, contralesional visual cortical activation was within expected striate and extrastriate sites, comparable to that seen in controls. Despite a further infarct in the right (previously unaffected hemisphere), there was evolution of visual cortical reorganization progressed. In this patient, there was evidence of utilization of peri-infarct sites (right-sided) and recruitment of new activation sites in extrastriate cortices, including in the lateral middle and inferior temporal lobes. The changes over time corresponded topographically with the patient's lesion site and its connections. Reorganization of the surviving visual cortex was demonstrated 8 days after the first stroke. Ongoing reorganization in extant cortex was demonstrated at the 6 month scan. We present a summary of mechanisms of recovery following stroke relevant to the visual system. We conclude that mature primary visual cortex displays considerable plasticity and capacity to reorganize, associated with evolution of visual field deficits. We discuss these findings and their implications for therapy within the context of current concepts in visual compensatory and restorative therapies.

  4. Reorganization of the Human Somatosensory Cortex in Hand Dystonia

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    Maria Jose Catalan

    2012-05-01

    Full Text Available Background and Purpose: Abnormalities of finger representations in the somatosensory cortex have been identified in patients with focal hand dystonia. Measuring blood flow with positron emission tomography (PET can be use to demonstrate functional localization of receptive fields. Methods: A vibratory stimulus was applied to the right thumb and little finger of six healthy volunteers and six patients with focal hand dystonia to map their receptive fields using H215O PET. Results: The cortical finger representations in the primary somatosensory cortex were closer to each other in patients than in normal subjects. No abnormalities were found in secondary somatosensory cortex, but the somatotopy there is less well distinguished. Conclusions: These data confirm prior electrophysiological and functional neuroimaging observations showing abnormalities of finger representations in somatosensory cortex of patients with focal hand dystonia.

  5. Early Hearing-Impairment Results in Crossmodal Reorganization of Ferret Core Auditory Cortex

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    M. Alex Meredith

    2012-01-01

    Full Text Available Numerous investigations of cortical crossmodal plasticity, most often in congenital or early-deaf subjects, have indicated that secondary auditory cortical areas reorganize to exhibit visual responsiveness while the core auditory regions are largely spared. However, a recent study of adult-deafened ferrets demonstrated that core auditory cortex was reorganized by the somatosensory modality. Because adult animals have matured beyond their critical period of sensory development and plasticity, it was not known if adult-deafening and early-deafening would generate the same crossmodal results. The present study used young, ototoxically-lesioned ferrets (n=3 that, after maturation (avg. = 173 days old, showed significant hearing deficits (avg. threshold = 72 dB SPL. Recordings from single-units (n=132 in core auditory cortex showed that 72% were activated by somatosensory stimulation (compared to 1% in hearing controls. In addition, tracer injection into early hearing-impaired core auditory cortex labeled essentially the same auditory cortical and thalamic projection sources as seen for injections in the hearing controls, indicating that the functional reorganization was not the result of new or latent projections to the cortex. These data, along with similar observations from adult-deafened and adult hearing-impaired animals, support the recently proposed brainstem theory for crossmodal plasticity induced by hearing loss.

  6. Task-specific reorganization of the auditory cortex in deaf humans.

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    Bola, Łukasz; Zimmermann, Maria; Mostowski, Piotr; Jednoróg, Katarzyna; Marchewka, Artur; Rutkowski, Paweł; Szwed, Marcin

    2017-01-24

    The principles that guide large-scale cortical reorganization remain unclear. In the blind, several visual regions preserve their task specificity; ventral visual areas, for example, become engaged in auditory and tactile object-recognition tasks. It remains open whether task-specific reorganization is unique to the visual cortex or, alternatively, whether this kind of plasticity is a general principle applying to other cortical areas. Auditory areas can become recruited for visual and tactile input in the deaf. Although nonhuman data suggest that this reorganization might be task specific, human evidence has been lacking. Here we enrolled 15 deaf and 15 hearing adults into an functional MRI experiment during which they discriminated between temporally complex sequences of stimuli (rhythms). Both deaf and hearing subjects performed the task visually, in the central visual field. In addition, hearing subjects performed the same task in the auditory modality. We found that the visual task robustly activated the auditory cortex in deaf subjects, peaking in the posterior-lateral part of high-level auditory areas. This activation pattern was strikingly similar to the pattern found in hearing subjects performing the auditory version of the task. Although performing the visual task in deaf subjects induced an increase in functional connectivity between the auditory cortex and the dorsal visual cortex, no such effect was found in hearing subjects. We conclude that in deaf humans the high-level auditory cortex switches its input modality from sound to vision but preserves its task-specific activation pattern independent of input modality. Task-specific reorganization thus might be a general principle that guides cortical plasticity in the brain.

  7. Mirror therapy in lower limb amputees--a look beyond primary motor cortex reorganization.

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    Seidel, S; Kasprian, G; Furtner, J; Schöpf, V; Essmeister, M; Sycha, T; Auff, E; Prayer, D

    2011-11-01

    Phantom pain in upper limb amputees is associated with the extent of reorganization in the primary sensorimotor cortex. Mirror visual feedback therapy has been shown to improve phantom pain. We investigated the extent of cortical reorganization in lower limb amputees and changes in neural activity induced by mirror therapy. Eight lower limb amputees underwent 12 sessions of MVFT and functional magnetic resonance imaging (fMRI) of the brain before the first and after the last MVFT session. FMRI sessions consisted of two runs in which subjects were instructed to perform repetitive movement of the healthy and phantom ankle. Before MVFT, the mean phantom pain intensity was 4.6 ± 3.1 on a visual analog scale and decreased to 1.8 ± 1.7 (p = 0.04). We did not observe a consistent pattern of cortical activation in primary sensorimotor areas during phantom limb movements. Following MVFT, increased activity was obtained in the right orbitofrontal cortex during phantom ankle movements. Comparison of cortical activity during movements of the phantom ankle and the intact ankle showed significantly higher activity in the left inferior frontal cortex (pars triangularis). These results question the known association between phantom pain and primary sensorimotor reorganization and propose reorganizational changes involving multiple cortical areas in lower limb amputees. Finally, reduction of phantom pain after mirror visual feedback therapy was associated with increased prefrontal cortical activity during phantom ankle movements. © Georg Thieme Verlag KG Stuttgart · New York.

  8. Mirror therapy in lower limb amputees. A look beyond primary motor cortex reorganization

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    Seidel, S.; Essmeister, M.; Sycha, T.; Auff, E. [Vienna Medical Univ. (Austria). Dept. of Neurology; Kasprian, G.; Furtner, J.; Schoepf, V.; Prayer, D. [Vienna Medical Univ. (Austria). Dept. of Neuroradiology

    2011-11-15

    Phantom pain in upper limb amputees is associated with the extent of reorganization in the primary sensorimotor cortex. Mirror visual feedback therapy has been shown to improve phantom pain. We investigated the extent of cortical reorganization in lower limb amputees and changes in neural activity induced by mirror therapy. Eight lower limb amputees underwent 12 sessions of MVFT and functional magnetic resonance imaging (fMRI) of the brain before the first and after the last MVFT session. FMRI sessions consisted of two runs in which subjects were instructed to perform repetitive movement of the healthy and phantom ankle. Before MVFT, the mean phantom pain intensity was 4.6 {+-} 3.1 on a visual analog scale and decreased to 1.8 {+-} 1.7 (p = 0.04). We did not observe a consistent pattern of cortical activation in primary sensorimotor areas during phantom limb movements. Following MVFT, increased activity was obtained in the right orbitofrontal cortex during phantom ankle movements. Comparison of cortical activity during movements of the phantom ankle and the intact ankle showed significantly higher activity in the left inferior frontal cortex (pars triangularis). These results question the known association between phantom pain and primary sensorimotor reorganization and propose reorganizational changes involving multiple cortical areas in lower limb amputees. Finally, reduction of phantom pain after mirror visual feedback therapy was associated with increased prefrontal cortical activity during phantom ankle movements. (orig.)

  9. Cross-Modal Functional Reorganization of Visual and Auditory Cortex in Adult Cochlear Implant Users Identified with fNIRS.

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    Chen, Ling-Chia; Sandmann, Pascale; Thorne, Jeremy D; Bleichner, Martin G; Debener, Stefan

    2016-01-01

    Cochlear implant (CI) users show higher auditory-evoked activations in visual cortex and higher visual-evoked activation in auditory cortex compared to normal hearing (NH) controls, reflecting functional reorganization of both visual and auditory modalities. Visual-evoked activation in auditory cortex is a maladaptive functional reorganization whereas auditory-evoked activation in visual cortex is beneficial for speech recognition in CI users. We investigated their joint influence on CI users' speech recognition, by testing 20 postlingually deafened CI users and 20 NH controls with functional near-infrared spectroscopy (fNIRS). Optodes were placed over occipital and temporal areas to measure visual and auditory responses when presenting visual checkerboard and auditory word stimuli. Higher cross-modal activations were confirmed in both auditory and visual cortex for CI users compared to NH controls, demonstrating that functional reorganization of both auditory and visual cortex can be identified with fNIRS. Additionally, the combined reorganization of auditory and visual cortex was found to be associated with speech recognition performance. Speech performance was good as long as the beneficial auditory-evoked activation in visual cortex was higher than the visual-evoked activation in the auditory cortex. These results indicate the importance of considering cross-modal activations in both visual and auditory cortex for potential clinical outcome estimation.

  10. Cross-Modal Functional Reorganization of Visual and Auditory Cortex in Adult Cochlear Implant Users Identified with fNIRS

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    Ling-Chia Chen

    2016-01-01

    Full Text Available Cochlear implant (CI users show higher auditory-evoked activations in visual cortex and higher visual-evoked activation in auditory cortex compared to normal hearing (NH controls, reflecting functional reorganization of both visual and auditory modalities. Visual-evoked activation in auditory cortex is a maladaptive functional reorganization whereas auditory-evoked activation in visual cortex is beneficial for speech recognition in CI users. We investigated their joint influence on CI users’ speech recognition, by testing 20 postlingually deafened CI users and 20 NH controls with functional near-infrared spectroscopy (fNIRS. Optodes were placed over occipital and temporal areas to measure visual and auditory responses when presenting visual checkerboard and auditory word stimuli. Higher cross-modal activations were confirmed in both auditory and visual cortex for CI users compared to NH controls, demonstrating that functional reorganization of both auditory and visual cortex can be identified with fNIRS. Additionally, the combined reorganization of auditory and visual cortex was found to be associated with speech recognition performance. Speech performance was good as long as the beneficial auditory-evoked activation in visual cortex was higher than the visual-evoked activation in the auditory cortex. These results indicate the importance of considering cross-modal activations in both visual and auditory cortex for potential clinical outcome estimation.

  11. Structural damage to the corticospinal tract correlates with bilateral sensorimotor cortex reorganization in stroke patients.

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    Schaechter, Judith D; Perdue, Katherine L; Wang, Ruopeng

    2008-02-01

    Damage to the corticospinal tract (CST) in stroke patients has been associated with functional reorganization in the ipsilesional and contralesional sensorimotor cortices. However, it is unknown whether a quantitative relationship exists between the extent of structural damage to the CST and functional reorganization in stroke patients. The purpose of the current study was to examine the relationship between structural CST damage and motor task-related cortical activity in chronic hemiparetic stroke patients. In 10 chronic hemiparetic stroke patients with heterogeneous lesions, CST damage was quantified using conventional structural magnetic resonance imaging and tractography based on diffusion tensor imaging. Cortical activity was measured using functional magnetic resonance imaging during repetitive flexion/extension movements of the digits. We found that the two measures of CST damage were strongly correlated. Moreover, greater CST damage was significantly and linearly correlated with increased activation during affected hand movement in the hand area of the contralesional primary sensorimotor cortex (M1/S1) and in the ipsilesional M1/S1 ventral to the hand area. To our knowledge, this is the first demonstration of a quantitative relationship between the extent of structural damage to the CST and functional reorganization in stroke patients. This relationship was observed in stroke patients with heterogeneous lesions, suggesting that CST damage is a factor relevant to the variation in functional reorganization in the clinical population.

  12. Reorganization of early visual cortex functional connectivity following selective peripheral and central visual loss.

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    Sabbah, Norman; Sanda, Nicolae; Authié, Colas N; Mohand-Saïd, Saddek; Sahel, José-Alain; Habas, Christophe; Amedi, Amir; Safran, Avinoam B

    2017-02-24

    Behavioral alterations emerging after central or peripheral vision loss suggest that cerebral reorganization occurs for both the afferented and deafferented early visual cortex (EVC). We explored the functional reorganization of the central and peripheral EVC following visual field defects specifically affecting central or peripheral vision. Compared to normally sighted, afferented central and peripheral EVC enhance their functional connectivity with areas involved in visual processing, whereas deafferented central and peripheral EVC increase their functional connectivity with more remote regions. The connectivity pattern of afferented EVC suggests adaptive changes that might enhance the visual processing capacity whereas the connectivity pattern of deafferented EVC may reflect the involvement of these regions in high-order mechanisms. Characterizing and understanding the plastic changes induced by these visual defects is essential for any attempt to develop efficient rehabilitation strategies.

  13. Reorganization of auditory cortex in early-deaf people: functional connectivity and relationship to hearing aid use.

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    Shiell, Martha M; Champoux, François; Zatorre, Robert J

    2015-01-01

    Cross-modal reorganization after sensory deprivation is a model for understanding brain plasticity. Although it is a well-documented phenomenon, we still know little of the mechanisms underlying it or the factors that constrain and promote it. Using fMRI, we identified visual motion-related activity in 17 early-deaf and 17 hearing adults. We found that, in the deaf, the posterior superior temporal gyrus (STG) was responsive to visual motion. We compared functional connectivity of this reorganized cortex between groups to identify differences in functional networks associated with reorganization. In the deaf more than the hearing, the STG displayed increased functional connectivity with a region in the calcarine fissure. We also explored the role of hearing aid use, a factor that may contribute to variability in cross-modal reorganization. We found that both the cross-modal activity in STG and the functional connectivity between STG and calcarine cortex correlated with duration of hearing aid use, supporting the hypothesis that residual hearing affects cross-modal reorganization. We conclude that early auditory deprivation alters not only the organization of auditory regions but also the interactions between auditory and primary visual cortex and that auditory input, as indexed by hearing aid use, may inhibit cross-modal reorganization in early-deaf people.

  14. Reassessing cortical reorganization in the primary sensorimotor cortex following arm amputation.

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    Makin, Tamar R; Scholz, Jan; Henderson Slater, David; Johansen-Berg, Heidi; Tracey, Irene

    2015-08-01

    The role of cortical activity in generating and abolishing chronic pain is increasingly emphasized in the clinical community. Perhaps the most striking example of this is the maladaptive plasticity theory, according to which phantom pain arises from remapping of cortically neighbouring representations (lower face) into the territory of the missing hand following amputation. This theory has been extended to a wide range of chronic pain conditions, such as complex regional pain syndrome. Yet, despite its growing popularity, the evidence to support the maladaptive plasticity theory is largely based on correlations between pain ratings and oftentimes crude measurements of cortical reorganization, with little consideration of potential contributions of other clinical factors, such as adaptive behaviour, in driving the identified brain plasticity. Here, we used a physiologically meaningful measurement of cortical reorganization to reassess its relationship to phantom pain in upper limb amputees. We identified small yet consistent shifts in lip representation contralateral to the missing hand towards, but not invading, the hand area. However, we were unable to identify any statistical relationship between cortical reorganization and phantom sensations or pain either with this measurement or with the traditional Euclidian distance measurement. Instead, we demonstrate that other factors may contribute to the observed remapping. Further research that reassesses more broadly the relationship between cortical reorganization and chronic pain is warranted.

  15. Pathway-specific reorganization of projection neurons in somatosensory cortex during learning.

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    Chen, Jerry L; Margolis, David J; Stankov, Atanas; Sumanovski, Lazar T; Schneider, Bernard L; Helmchen, Fritjof

    2015-08-01

    In the mammalian brain, sensory cortices exhibit plasticity during task learning, but how this alters information transferred between connected cortical areas remains unknown. We found that divergent subpopulations of cortico-cortical neurons in mouse whisker primary somatosensory cortex (S1) undergo functional changes reflecting learned behavior. We chronically imaged activity of S1 neurons projecting to secondary somatosensory (S2) or primary motor (M1) cortex in mice learning a texture discrimination task. Mice adopted an active whisking strategy that enhanced texture-related whisker kinematics, correlating with task performance. M1-projecting neurons reliably encoded basic kinematics features, and an additional subset of touch-related neurons was recruited that persisted past training. The number of S2-projecting touch neurons remained constant, but improved their discrimination of trial types through reorganization while developing activity patterns capable of discriminating the animal's decision. We propose that learning-related changes in S1 enhance sensory representations in a pathway-specific manner, providing downstream areas with task-relevant information for behavior.

  16. Functional Reorganization of the Primary Somatosensory Cortex of a Phantom Limb Pain Patient.

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    Zhao, Jia; Guo, Xiaoli; Xia, Xiaolei; Peng, Weiwei; Wang, Wuchao; Li, Shulin; Zhang, Ya; Hu, Li

    2016-07-01

    Functional reorganization of the somatosensory system was widely observed in phantom limb pain patients. Whereas some studies demonstrated that the primary somatosensory cortex (S1) of the amputated limb was engaged with the regions around it, others showed that phantom limb pain was associated with preserved structure and functional organization in the former brain region. However, according to the law of use and disuse, the sensitivity of S1 of the amputated limb to pain-related context should be enhanced due to the adaptation to the long-lasting phantom limb pain experience. Here, we collected neurophysiological data from a patient with 21-year phantom limb pain using electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) techniques. EEG data showed that both laser-evoked potentials (LEPs) and tactile-evoked potentials (TEPs) were clearly presented only when radiant-heat laser pulses and electrical pulses were delivered to the shoulder of the healthy limb, but not of the amputated limb. This observation suggested the functional deficit of somatosensory pathways at the amputated side. FMRI data showed that significant larger brain activations by painful rather than non-painful stimuli in video clips were observed not only at visual-related brain areas and anterior/mid-cingulate cortex, but also at S1 contralateral to the amputated limb. This observation suggested the increased sensitivity of S1 of the amputated limb to the pain-related context. In addition, such increase of sensitivity was significantly larger if the context was associated with the amputated limb of the patient. In summary, our findings provided novel evidence for a possible neuroplasticity of S1 of the amputated limb: in an amputee with long-lasting phantom limb pain, the sensitivity of S1 to pain-related and amputated-limb-related context was greatly enhanced.

  17. Trunk robot rehabilitation training with active stepping reorganizes and enriches trunk motor cortex representations in spinal transected rats.

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    Oza, Chintan S; Giszter, Simon F

    2015-05-01

    Trunk motor control is crucial for postural stability and propulsion after low thoracic spinal cord injury (SCI) in animals and humans. Robotic rehabilitation aimed at trunk shows promise in SCI animal models and patients. However, little is known about the effect of SCI and robot rehabilitation of trunk on cortical motor representations. We previously showed reorganization of trunk motor cortex after adult SCI. Non-stepping training also exacerbated some SCI-driven plastic changes. Here we examine effects of robot rehabilitation that promotes recovery of hindlimb weight support functions on trunk motor cortex representations. Adult rats spinal transected as neonates (NTX rats) at the T9/10 level significantly improve function with our robot rehabilitation paradigm, whereas treadmill-only trained do not. We used intracortical microstimulation to map motor cortex in two NTX groups: (1) treadmill trained (control group); and (2) robot-assisted treadmill trained (improved function group). We found significant robot rehabilitation-driven changes in motor cortex: (1) caudal trunk motor areas expanded; (2) trunk coactivation at cortex sites increased; (3) richness of trunk cortex motor representations, as examined by cumulative entropy and mutual information for different trunk representations, increased; (4) trunk motor representations in the cortex moved toward more normal topography; and (5) trunk and forelimb motor representations that SCI-driven plasticity and compensations had caused to overlap were segregated. We conclude that effective robot rehabilitation training induces significant reorganization of trunk motor cortex and partially reverses some plastic changes that may be adaptive in non-stepping paraplegia after SCI.

  18. Trunk Robot Rehabilitation Training with Active Stepping Reorganizes and Enriches Trunk Motor Cortex Representations in Spinal Transected Rats

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    Oza, Chintan S.

    2015-01-01

    Trunk motor control is crucial for postural stability and propulsion after low thoracic spinal cord injury (SCI) in animals and humans. Robotic rehabilitation aimed at trunk shows promise in SCI animal models and patients. However, little is known about the effect of SCI and robot rehabilitation of trunk on cortical motor representations. We previously showed reorganization of trunk motor cortex after adult SCI. Non-stepping training also exacerbated some SCI-driven plastic changes. Here we examine effects of robot rehabilitation that promotes recovery of hindlimb weight support functions on trunk motor cortex representations. Adult rats spinal transected as neonates (NTX rats) at the T9/10 level significantly improve function with our robot rehabilitation paradigm, whereas treadmill-only trained do not. We used intracortical microstimulation to map motor cortex in two NTX groups: (1) treadmill trained (control group); and (2) robot-assisted treadmill trained (improved function group). We found significant robot rehabilitation-driven changes in motor cortex: (1) caudal trunk motor areas expanded; (2) trunk coactivation at cortex sites increased; (3) richness of trunk cortex motor representations, as examined by cumulative entropy and mutual information for different trunk representations, increased; (4) trunk motor representations in the cortex moved toward more normal topography; and (5) trunk and forelimb motor representations that SCI-driven plasticity and compensations had caused to overlap were segregated. We conclude that effective robot rehabilitation training induces significant reorganization of trunk motor cortex and partially reverses some plastic changes that may be adaptive in non-stepping paraplegia after SCI. PMID:25948267

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

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    Veronesi, Carlo; Maggiolini, Emma; Franchi, Gianfranco

    2013-10-01

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

  20. Kinetics of structural reorganizations in multilamellarphotosynthetic membranes monitored by small-angle neutronscattering

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    Nagy, Gergely; Kovacs, Laszlo; Unnep, Renata;

    2013-01-01

    We demonstrate the power of time-resolved small-angle neutron scattering experiments for the investigation of the structure and structural reorganizations of multilamellar photosynthetic membranes. In addition to briefly summarizing our results on thylakoid membranes isolated from higher plants a...

  1. Reorganizing the intrinsic functional architecture of the human primary motor cortex during rest with non-invasive cortical stimulation.

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    Rafael Polanía

    Full Text Available The primary motor cortex (M1 is the main effector structure implicated in the generation of voluntary movements and is directly involved in motor learning. The intrinsic horizontal neuronal connections of M1 exhibit short-term and long-term plasticity, which is a strong substrate for learning-related map reorganization. Transcranial direct current stimulation (tDCS applied for few minutes over M1 has been shown to induce relatively long-lasting plastic alterations and to modulate motor performance. Here we test the hypothesis that the relatively long-lasting synaptic modification induced by tDCS over M1 results in the alteration of associations among populations of M1 neurons which may be reflected in changes of its functional architecture. fMRI resting-state datasets were acquired immediately before and after 10 minutes of tDCS during rest, with the anode/cathode placed over the left M1. For each functional dataset, grey-matter voxels belonging to Brodmann area 4 (BA4 were labelled and afterwards BA4 voxel-based synchronization matrices were calculated and thresholded to construct undirected graphs. Nodal network parameters which characterize the architecture of functional networks (connectivity degree, clustering coefficient and characteristic path-length were computed, transformed to volume maps and compared before and after stimulation. At the dorsolateral-BA4 region cathodal tDCS boosted local connectedness, while anodal-tDCS enhanced long distance functional communication within M1. Additionally, the more efficient the functional architecture of M1 was at baseline, the more efficient the tDCS-induced functional modulations were. In summary, we show here that it is possible to non-invasively reorganize the intrinsic functional architecture of M1, and to image such alterations.

  2. Motor cortex excitability and connectivity in chronic stroke: a multimodal model of functional reorganization.

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    Volz, Lukas J; Sarfeld, Anna-Sophia; Diekhoff, Svenja; Rehme, Anne K; Pool, Eva-Maria; Eickhoff, Simon B; Fink, Gereon R; Grefkes, Christian

    2015-03-01

    Cerebral ischemia triggers a cascade of cellular processes, which induce neuroprotection, inflammation, apoptosis and regeneration. At the neural network level, lesions concomitantly induce cerebral plasticity. Yet, many stroke survivors are left with a permanent motor deficit, and only little is known about the neurobiological factors that determine functional outcome after stroke. Transcranial magnetic stimulation (TMS) and magnetic resonance imaging (MRI) are non-invasive approaches that allow insights into the functional (re-) organization of the cortical motor system. We here combined neuronavigated TMS, MRI and analyses of connectivity to investigate to which degree recovery of hand function depends on corticospinal tract (CST) damage and biomarkers of cerebral plasticity like cortical excitability and motor network effective connectivity. As expected, individual motor performance of 12 stroke patients with persistent motor deficits was found to depend upon the degree of CST damage but also motor cortex excitability and interhemispheric connectivity. In addition, the data revealed a strong correlation between reduced ipsilesional motor cortex excitability and reduced interhemispheric inhibition in severely impaired patients. Interindividual differences in ipsilesional motor cortex excitability were stronger related to the motor deficit than abnormal interhemispheric connectivity or CST damage. Multivariate linear regression analysis combining the three factors accounted for more than 80 % of the variance in functional impairment. The inter-relation of cortical excitability and reduced interhemispheric inhibition provides direct multi-modal evidence for the disinhibition theory of the contralesional hemisphere following stroke. Finally, our data reveal a key mechanism (i.e., the excitability-related reduction in interhemispheric inhibition) accounting for the rehabilitative potential of novel therapeutic approaches which aim at modulating cortical

  3. Reorganization of the rat cerebellar cortex during postnatal development following cisplatin treatment.

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    Avella, D; Pisu, M B; Roda, E; Gravati, M; Bernocchi, G

    2006-09-01

    We examined the effects of the antitumor agent cisplatin on the development and plasticity of cerebellar cytoarchitecture. Since knowledge of the parallel and climbing fiber-Purkinje cell system is important in order to determine the architectural basis of cerebellar function, we used immunofluorescence for vesicular glutamate transporters (VGluT1 and VGluT2) to evaluate the trend of synaptogenesis of parallel and climbing fibers on Purkinje cells in the cerebellum vermis after a single injection of cisplatin to 10-day-old rats, i.e., during a crucial period of cerebellar development. The temporal and spatial patterns of VGluT1 and VGluT2 immunoreactivity after the early cisplatin injury provided evidence that remodeling of excitatory afferents and Purkinje cell dendrites occurs. After an early slow down of Purkinje cell dendrite growth, 7 days following the treatment, the extension of the molecular layer was reduced, as was parallel fiber innervation, but VGluT1 immunoreactive fibers contacted Purkinje cell dendrite branches extending within the external granular layer. VGluT2 immunopositive climbing fiber varicosities were still largely present on the soma and stem dendrites of Purkinje cells. Twenty days after the cisplatin injection, the thickness of the VGluT1 immunopositive molecular layer was reduced. VGluT2 climbing fiber varicosities were found on the remodeled Purkinje cell dendrites, as in controls, although at a lower density. Alterations in the immunoreactivity for polysialic acid neural cell adhesion molecule (PSA-NCAM) during the recovery phase suggest that this molecule plays a fundamental role not only during development, but also in the reorganization of neuroarchitecture. The changes were restricted to the neocerebellar vermis and were likely dependent on the different timing of lobule formation. The results of these investigations reveal the existence of vulnerability windows of the cerebellum to exposure to experimental or environmental

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

    Science.gov (United States)

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

    2012-12-07

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

  5. Pain and emotion in the insular cortex: evidence for functional reorganization in major depression.

    Science.gov (United States)

    Mutschler, Isabella; Ball, Tonio; Wankerl, Johanna; Strigo, Irina A

    2012-06-29

    Major Depressive Disorder (MDD) is among the top causes of disability worldwide and many patients with depression experience pain symptoms. Little is known regarding what makes depressed persons feel like they are in pain. An increasing number of neuroimaging studies show that both physical pain and depression involve the insular cortex. The present study aimed to investigate whether emotional processing in MDD patients is topologically shifted towards the insular area(s) involved in pain processing in healthy individuals. To achieve this aim, we investigated the functional organization of the insula by conducting meta-analyses of previously published neuroimaging studies on: (1) emotion in patients with MDD, (2) emotion in healthy subjects, and (3) physical pain in healthy subjects. Our results show that the dorsal part of the insula is reproducibly activated during experimental pain in healthy individuals, with multiple separate pain-related areas aligned along its dorsal border. Regions with maximal pain-related activation likelihood estimate (ALE) were located in the posterior (left) and dorsal mid-anterior insula (left and right). Furthermore, emotion-related peaks in healthy subjects were found both in its ventral (as shown in a previous meta-analysis) and dorsal anterior part. Importantly, emotion-related peaks in depressed patients were shifted to the dorsal anterior insula, where regions related to physical pain in healthy subjects are located. This shift was reflected in the observation that median z-coordinates of emotion-related responses in the left hemisphere were significantly larger in depressed patients than in healthy controls. This shift of emotion-related responses to the dorsal insula, i.e., where pain-processing takes place in healthy subjects, may play a role in "emotional allodynia" - a notion that individuals with MDD experience pain in response to stimuli that are normally not painful.

  6. Surface hopping outperforms secular Redfield theory when reorganization energies range from small to moderate (and nuclei are classical)

    Energy Technology Data Exchange (ETDEWEB)

    Landry, Brian R., E-mail: landrybr@gmail.com; Subotnik, Joseph E. [Department of Chemistry, University of Pennsylvania, 231 S. 34th Street, Philadelphia, Pennsylvania 19104 (United States)

    2015-03-14

    We evaluate the accuracy of Tully’s surface hopping algorithm for the spin-boson model in the limit of small to moderate reorganization energy. We calculate transition rates between diabatic surfaces in the exciton basis and compare against exact results from the hierarchical equations of motion; we also compare against approximate rates from the secular Redfield equation and Ehrenfest dynamics. We show that decoherence-corrected surface hopping performs very well in this regime, agreeing with secular Redfield theory for very weak system-bath coupling and outperforming secular Redfield theory for moderate system-bath coupling. Surface hopping can also be extended beyond the Markovian limits of standard Redfield theory. Given previous work [B. R. Landry and J. E. Subotnik, J. Chem. Phys. 137, 22A513 (2012)] that establishes the accuracy of decoherence-corrected surface-hopping in the Marcus regime, this work suggests that surface hopping may well have a very wide range of applicability.

  7. Reversible membrane reorganizations during photosynthesis in vivo: revealed by small-angle neutron scattering

    DEFF Research Database (Denmark)

    Nagy, Gergely; Posselt, Dorthe; Kovacs, Laszlo

    2011-01-01

    In the present study, we determined characteristic repeat distances of the photosynthetic membranes in living cyanobacterial and eukaryotic algal cells, and in intact thylakoid membranes isolated from higher plants with time-resolved small-angle neutron scattering. This non-invasive technique rev...

  8. Dynamic alterations of the levels of tumor necrosis factor-α, interleukin-6, and interleukin-1β in rat primary motor cortex during transhemispheric functional reorganization after contralateral seventh cervical spinal nerve root transfer following brachial plexus avulsion injuries.

    Science.gov (United States)

    Yang, Ming-Jie; Li, Shuang; Yang, Chen-Song; Wang, Xu-Jia; Chang, Shi-Min; Sun, Gui-Xin

    2017-03-22

    The transfer of a contralateral healthy seventh cervical spinal nerve root (cC7) to the recipient nerve in the injured side is considered a reliable and effective procedure for restoration of the physiological functions of an injured hand after brachial plexus root avulsion injury (BPAI). Growing evidence shows that the transhemispheric cortical reorganization is induced after cC7 nerve transfer surgery. However, little is known about the underlying molecular mechanism. Proinflammatory cytokines reportedly play an important role in the neural plasticity. We hypothesize that proinflammatory cytokines are involved in the transhemispheric functional reorganization after cC7 transfer. In the present study, we investigated the level of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β) in the rat primary motor cortex after cC7 transfer following BPAI by enzyme-linked immunosorbent assay. The results showed that, in the sham group, no statistical significance was observed between the level of TNF-α, IL-6, and IL-1β at each time point after the operation compared with that at day 0, respectively. However, in the unrepaired and repaired groups, the level of TNF-α, IL-6, and IL-1β changed dynamically. The study is the first to provide evidence for the involvement of proinflammatory cytokines in transhemispheric functional reorganization after cC7 transfer following BPAI, which are useful for understanding the underlying mechanism.

  9. Massive cortical reorganization in sighted Braille readers.

    Science.gov (United States)

    Siuda-Krzywicka, Katarzyna; Bola, Łukasz; Paplińska, Małgorzata; Sumera, Ewa; Jednoróg, Katarzyna; Marchewka, Artur; Śliwińska, Magdalena W; Amedi, Amir; Szwed, Marcin

    2016-03-15

    The brain is capable of large-scale reorganization in blindness or after massive injury. Such reorganization crosses the division into separate sensory cortices (visual, somatosensory...). As its result, the visual cortex of the blind becomes active during tactile Braille reading. Although the possibility of such reorganization in the normal, adult brain has been raised, definitive evidence has been lacking. Here, we demonstrate such extensive reorganization in normal, sighted adults who learned Braille while their brain activity was investigated with fMRI and transcranial magnetic stimulation (TMS). Subjects showed enhanced activity for tactile reading in the visual cortex, including the visual word form area (VWFA) that was modulated by their Braille reading speed and strengthened resting-state connectivity between visual and somatosensory cortices. Moreover, TMS disruption of VWFA activity decreased their tactile reading accuracy. Our results indicate that large-scale reorganization is a viable mechanism recruited when learning complex skills.

  10. Small scale module of the rat granular retrosplenial cortex: an example of minicolumn-like structure of the cerebral cortex

    Directory of Open Access Journals (Sweden)

    Noritaka eIchinohe

    2012-01-01

    Full Text Available Structures associated with the small scale module called minicolumn can be observed frequently in the cerebral cortex. However, the description of functional characteristics remains obscure. A significant confounding factor is the marked variability both in the definition of a minicolumn and in the diagnostic markers for identifying a minicolumn (see for review, Jones, 2000, DeFelipe et al., 2003; Rockland and Ichinohe, 2004. Within a minicolumn, cell columns are easily visualized by conventional Nissl staining. Dendritic bundles were first discovered with Golgi methods, but are more easily seen with MAP2-immunohistochemisty. Myelinated axon bundles can be seen by Tau-immunohistochemistry or myelin staining. Axon bundles of double bouquet cell can be seen by calbindin-immunohistochemistry. The spatial interrelationship among these morphological elements is more complex than expected and is neither clear nor unanimously agreed upon. In this review, I would like to focus first on the minicolumnar structure found in layers 1 and 2 of the rat granular retrosplenial cortex (GRS. This modular structure was first discovered as a combination of prominent apical dendritic bundles from layer 2 pyramidal neurons and spatially-matched thalamocortical patchy inputs (Wyss et al., 2000. Further examination showed more intricate components of this modular structure, which will be reviewed in this paper. Second, the postnatal development of this structure and potential molecular players for its formation will be reviewed. Thirdly, I will discuss how this modular organization is transformed in mutant rodents with a disorganized layer structure in the cerebral cortex (i.e., reeler mouse and Shaking Rat Kawasaki. Lastly, the potential significance of this type of module will be discussed.

  11. Drilling reorganizes

    Science.gov (United States)

    Richman, Barbara T.

    As the first in a proposed series of steps that would move scientific ocean drilling from its own niche within the National Science Foundation's (NSF) Directorate for Astronomical, Atmospheric, Earth, and Ocean Sciences (AAEO) into the agency's Division of Ocean Sciences, Grant Gross, division director, has been appointed acting director of the Office of Scientific Ocean Drilling (OSOD). Gross will retain the directorship of the division, which also is part of AAEO. Allen M. Shinn, Jr., OSOD director for nearly 2 years, has been reassigned effective July 10 to a position in NSF's Office of Planning and Resource Management.The move aims to tie drilling operations more closely to the science with which it is associated, Gross said. This first step is an organizational response to the current leaning toward using a commercial drilling vessel as the drilling platform, he said. Before the market for such commercial drill ships opened (Eos, February 22, 1983, p . 73), other ship options for scientific ocean drilling included refurbishing the aging Glomar Challenger or renovating, at great expense, the Glomar Explorer. A possible next step in the reorganization is to make OSOD the third section within the Ocean Sciences Division. Currently, the division is divided into the Oceanographic Facilities and Support Section and the Ocean Sciences Research Section.

  12. A small-world-based population encoding model of the primary visual cortex.

    Science.gov (United States)

    Shi, Li; Niu, Xiaoke; Wan, Hong; Shang, Zhigang; Wang, Zhizhong

    2015-06-01

    A wide range of evidence has shown that information encoding performed by the visual cortex involves complex activities of neuronal populations. However, the effects of the neuronal connectivity structure on the population's encoding performance remain poorly understood. In this paper, a small-world-based population encoding model of the primary visual cortex (V1) is established on the basis of the generalized linear model (GLM) to describe the computation of the neuronal population. The model mainly consists of three sets of filters, including a spatiotemporal stimulus filter, a post-spike history filter, and a set of coupled filters with the coupling neurons organizing as a small-world network. The parameters of the model were fitted with neuronal data of the rat V1 recorded with a micro-electrode array. Compared to the traditional GLM, without considering the small-world structure of the neuronal population, the proposed model was proved to produce more accurate spiking response to grating stimuli and enhance the capability of the neuronal population to carry information. The comparison results proved the validity of the proposed model and further suggest the role of small-world structure in the encoding performance of local populations in V1, which provides new insights for understanding encoding mechanisms of a small scale population in visual system.

  13. Massive cortical reorganization in sighted Braille readers

    Science.gov (United States)

    Siuda-Krzywicka, Katarzyna; Bola, Łukasz; Paplińska, Małgorzata; Sumera, Ewa; Jednoróg, Katarzyna; Marchewka, Artur; Śliwińska, Magdalena W; Amedi, Amir; Szwed, Marcin

    2016-01-01

    The brain is capable of large-scale reorganization in blindness or after massive injury. Such reorganization crosses the division into separate sensory cortices (visual, somatosensory...). As its result, the visual cortex of the blind becomes active during tactile Braille reading. Although the possibility of such reorganization in the normal, adult brain has been raised, definitive evidence has been lacking. Here, we demonstrate such extensive reorganization in normal, sighted adults who learned Braille while their brain activity was investigated with fMRI and transcranial magnetic stimulation (TMS). Subjects showed enhanced activity for tactile reading in the visual cortex, including the visual word form area (VWFA) that was modulated by their Braille reading speed and strengthened resting-state connectivity between visual and somatosensory cortices. Moreover, TMS disruption of VWFA activity decreased their tactile reading accuracy. Our results indicate that large-scale reorganization is a viable mechanism recruited when learning complex skills. DOI: http://dx.doi.org/10.7554/eLife.10762.001 PMID:26976813

  14. Patterns of Activity in the Human Frontal and Parietal Cortex Differentiate Large and Small Saccades

    Directory of Open Access Journals (Sweden)

    Marie-Helene Grosbras

    2016-10-01

    Full Text Available A vast literature indicates that small and large saccades, respectively, subserve different perceptual and cognitive strategies and may rely on different programming modes. While it is well established that in monkeys’ main oculomotor brain regions small and large eye movements are controlled by segregated neuronal populations, the representation of saccade amplitude in the human brain remains unclear. To address this question we used functional magnetic resonance imaging (fMRI to scan participants while they performed saccades towards targets at either short (4 degrees or large (30 degrees eccentricity. A regional multivoxel pattern analysis (MVPA reveals that patterns of activity in the frontal (FEF and parietal eye fields discriminate between the execution of large or small saccades. This was not the case in the supplementary eye fields nor in the inferior precentral cortex. These findings provide the first evidence of a representation of saccadic eye movement size in the fronto-parietal occulomotor circuit. They shed light on the respective roles of the different cortical oculomotor regions with respect to space perception and exploration, as well as on the homology of eye movement control between human and non-human primates.

  15. Reorganization of the connectivity of cortical field DZ in congenitally deaf cat.

    Directory of Open Access Journals (Sweden)

    Pascal Barone

    Full Text Available Psychophysics and brain imaging studies in deaf patients have revealed a functional crossmodal reorganization that affects the remaining sensory modalities. Similarly, the congenital deaf cat (CDC shows supra-normal visual skills that are supported by specific auditory fields (DZ-dorsal zone and P-posterior auditory cortex but not the primary auditory cortex (A1. To assess the functional reorganization observed in deafness we analyzed the connectivity pattern of the auditory cortex by means of injections of anatomical tracers in DZ and A1 in both congenital deaf and normally hearing cats. A quantitative analysis of the distribution of the projecting neurons revealed the presence of non-auditory inputs to both A1 and DZ of the CDC which were not observed in the hearing cats. Firstly, some visual (areas 19/20 and somatosensory (SIV areas were projecting toward DZ of the CDC but not in the control. Secondly, A1 of the deaf cat received a weak projection from the visual lateral posterior nuclei (LP. Most of these abnormal projections to A1 and DZ represent only a small fraction of the normal inputs to these areas. In addition, most of the afferents to DZ and A1 appeared normal in terms of areal specificity and strength of projection, with preserved but smeared nucleotopic gradient of A1 in CDCs. In conclusion, while the abnormal projections revealed in the CDC can participate in the crossmodal compensatory mechanisms, the observation of a limited reorganization of the connectivity pattern of the CDC implies that functional reorganization in congenital deafness is further supported also by normal cortico-cortical connectivity.

  16. A Small Motor Cortex Lesion Abolished Ocular Dominance Plasticity in the Adult Mouse Primary Visual Cortex and Impaired Experience-Dependent Visual Improvements.

    Science.gov (United States)

    Pielecka-Fortuna, Justyna; Kalogeraki, Evgenia; Greifzu, Franziska; Löwel, Siegrid

    2015-01-01

    It was previously shown that a small lesion in the primary somatosensory cortex (S1) prevented both cortical plasticity and sensory learning in the adult mouse visual system: While 3-month-old control mice continued to show ocular dominance (OD) plasticity in their primary visual cortex (V1) after monocular deprivation (MD), age-matched mice with a small photothrombotically induced (PT) stroke lesion in S1, positioned at least 1 mm anterior to the anterior border of V1, no longer expressed OD-plasticity. In addition, in the S1-lesioned mice, neither the experience-dependent increase of the spatial frequency threshold ("visual acuity") nor of the contrast threshold ("contrast sensitivity") of the optomotor reflex through the open eye was present. To assess whether these plasticity impairments can also occur if a lesion is placed more distant from V1, we tested the effect of a PT-lesion in the secondary motor cortex (M2). We observed that mice with a small M2-lesion restricted to the superficial cortical layers no longer expressed an OD-shift towards the open eye after 7 days of MD in V1 of the lesioned hemisphere. Consistent with previous findings about the consequences of an S1-lesion, OD-plasticity in V1 of the nonlesioned hemisphere of the M2-lesioned mice was still present. In addition, the experience-dependent improvements of both visual acuity and contrast sensitivity of the open eye were severely reduced. In contrast, sham-lesioned mice displayed both an OD-shift and improvements of visual capabilities of their open eye. To summarize, our data indicate that even a very small lesion restricted to the superficial cortical layers and more than 3mm anterior to the anterior border of V1 compromised V1-plasticity and impaired learning-induced visual improvements in adult mice. Thus both plasticity phenomena cannot only depend on modality-specific and local nerve cell networks but are clearly influenced by long-range interactions even from distant brain regions.

  17. A Small Motor Cortex Lesion Abolished Ocular Dominance Plasticity in the Adult Mouse Primary Visual Cortex and Impaired Experience-Dependent Visual Improvements

    Science.gov (United States)

    Pielecka-Fortuna, Justyna; Kalogeraki, Evgenia; Greifzu, Franziska; Löwel, Siegrid

    2015-01-01

    It was previously shown that a small lesion in the primary somatosensory cortex (S1) prevented both cortical plasticity and sensory learning in the adult mouse visual system: While 3-month-old control mice continued to show ocular dominance (OD) plasticity in their primary visual cortex (V1) after monocular deprivation (MD), age-matched mice with a small photothrombotically induced (PT) stroke lesion in S1, positioned at least 1 mm anterior to the anterior border of V1, no longer expressed OD-plasticity. In addition, in the S1-lesioned mice, neither the experience-dependent increase of the spatial frequency threshold (“visual acuity”) nor of the contrast threshold (“contrast sensitivity”) of the optomotor reflex through the open eye was present. To assess whether these plasticity impairments can also occur if a lesion is placed more distant from V1, we tested the effect of a PT-lesion in the secondary motor cortex (M2). We observed that mice with a small M2-lesion restricted to the superficial cortical layers no longer expressed an OD-shift towards the open eye after 7 days of MD in V1 of the lesioned hemisphere. Consistent with previous findings about the consequences of an S1-lesion, OD-plasticity in V1 of the nonlesioned hemisphere of the M2-lesioned mice was still present. In addition, the experience-dependent improvements of both visual acuity and contrast sensitivity of the open eye were severely reduced. In contrast, sham-lesioned mice displayed both an OD-shift and improvements of visual capabilities of their open eye. To summarize, our data indicate that even a very small lesion restricted to the superficial cortical layers and more than 3mm anterior to the anterior border of V1 compromised V1-plasticity and impaired learning-induced visual improvements in adult mice. Thus both plasticity phenomena cannot only depend on modality-specific and local nerve cell networks but are clearly influenced by long-range interactions even from distant brain

  18. PDGF induces reorganization of vimentin filaments.

    Science.gov (United States)

    Valgeirsdóttir, S; Claesson-Welsh, L; Bongcam-Rudloff, E; Hellman, U; Westermark, B; Heldin, C H

    1998-07-30

    In this study we demonstrate that stimulation with platelet-derived growth factor (PDGF) leads to a marked reorganization of the vimentin filaments in porcine aortic endothelial (PAE) cells ectopically expressing the PDGF beta-receptor. Within 20 minutes after stimulation, the well-spread fine fibrillar vimentin was reorganized as the filaments aggregated into a dense coil around the nucleus. The solubility of vimentin upon Nonidet-P40-extraction of cells decreased considerably after PDGF stimulation, indicating that PDGF caused a redistribution of vimentin to a less soluble compartment. In addition, an increased tyrosine phosphorylation of vimentin was observed. The redistribution of vimentin was not a direct consequence of its tyrosine phosphorylation, since treatment of cells with an inhibitor for the cytoplasmic tyrosine kinase Src, attenuated phosphorylation but not redistribution of vimentin. These changes in the distribution of vimentin occurred in conjunction with reorganization of actin filaments. In PAE cells expressing a Y740/751F mutant receptor that is unable to bind and activate phosphatidylinositol 3'-kinase (PI3-kinase), the distribution of vimentin was virtually unaffected by PDGF stimulation. Thus, PI3-kinase is important for vimentin reorganization, in addition to its previously demonstrated role in actin reorganization. The small GTPase Rac has previously been shown to be involved downstream of PI3-kinase in the reorganization of actin filaments. In PAE cells overexpressing dominant negative Rac1 (N17Rac1), no change in the fine fibrillar vimentin network was seen after PDGF-BB stimulation, whereas in PAE cells overexpressing constitutively active Rac1 (V12Rac1), there was a dramatic change in vimentin filament organization independent of PDGF stimulation. These data indicate that PDGF causes a reorganization of microfilaments as well as intermediate filaments in its target cells and suggest an important role for Rac downstream of PI3-kinase in

  19. Large-Scale Functional Brain Network Reorganization During Taoist Meditation.

    Science.gov (United States)

    Jao, Tun; Li, Chia-Wei; Vértes, Petra E; Wu, Changwei Wesley; Achard, Sophie; Hsieh, Chao-Hsien; Liou, Chien-Hui; Chen, Jyh-Horng; Bullmore, Edward T

    2016-02-01

    Meditation induces a distinct and reversible mental state that provides insights into brain correlates of consciousness. We explored brain network changes related to meditation by graph theoretical analysis of resting-state functional magnetic resonance imaging data. Eighteen Taoist meditators with varying levels of expertise were scanned using a within-subjects counterbalanced design during resting and meditation states. State-related differences in network topology were measured globally and at the level of individual nodes and edges. Although measures of global network topology, such as small-worldness, were unchanged, meditation was characterized by an extensive and expertise-dependent reorganization of the hubs (highly connected nodes) and edges (functional connections). Areas of sensory cortex, especially the bilateral primary visual and auditory cortices, and the bilateral temporopolar areas, which had the highest degree (or connectivity) during the resting state, showed the biggest decrease during meditation. Conversely, bilateral thalamus and components of the default mode network, mainly the bilateral precuneus and posterior cingulate cortex, had low degree in the resting state but increased degree during meditation. Additionally, these changes in nodal degree were accompanied by reorganization of anatomical orientation of the edges. During meditation, long-distance longitudinal (antero-posterior) edges increased proportionally, whereas orthogonal long-distance transverse (right-left) edges connecting bilaterally homologous cortices decreased. Our findings suggest that transient changes in consciousness associated with meditation introduce convergent changes in the topological and spatial properties of brain functional networks, and the anatomical pattern of integration might be as important as the global level of integration when considering the network basis for human consciousness.

  20. Reorganization of visual processing in macular degeneration is not specific to the "preferred retinal locus".

    Science.gov (United States)

    Dilks, Daniel D; Baker, Chris I; Peli, Eli; Kanwisher, Nancy

    2009-03-04

    Recent work has shown that foveal cortex, deprived of its normal bottom-up input as a result of macular degeneration (MD), begins responding to stimuli presented to a peripheral retinal location. However, these studies have only presented stimuli to the "preferred retinal location," or PRL, a spared part of the peripheral retina used by individuals with MD for fixating, face recognition, reading, and other visual tasks. Thus, previous research has not yet answered a question critical for understanding the mechanisms underlying this reorganization: Does formerly foveal cortex respond only to stimuli presented at the PRL, or does it also respond to other peripheral locations of similar eccentricity? If foveal cortex responds to stimuli at PRL because it is the long-term habitual use of this region as a functional fovea that drives the formerly foveal cortex to respond to stimuli presented at the PRL (the "use-dependent reorganization" hypothesis), then foveal cortex will not respond to stimuli presented at other locations. Alternatively, it may be that foveal cortex responds to any peripheral retinal input, independent of whether input at that retinal location has been chronically attended for months or years (the "use-independent reorganization" hypothesis). Using fMRI, we found clear activation of formerly foveal cortex to stimuli presented at either the PRL or an isoeccentric non-PRL location in two individuals with MD, supporting the use-independent reorganization hypothesis. This finding suggests that reorganization is driven by passive, not use-dependent mechanisms.

  1. The Reorganization Law in Poland

    Directory of Open Access Journals (Sweden)

    Rafał ADAMUS

    2012-03-01

    Full Text Available The aim of this paper is to present general remarks of the legal structure of the Polish reorganization law. This is a completely new institution in Poland. The Act of 28 February 2003 the Bankruptcy and Reorganization Law (J.L. No 60, item 535 as amended, the articles 492 - 521 b.r.l. is the main source of law in the commented matter. The idea of the Polish regulation derives from the Chapter 11 of the Bankruptcy Code of the United States. The statistics of the usage of the reorganization proceedings in Poland are not very impressive. In this respect some critics maintain that the legislative experiment called “reorganization proceedings” is unsuccessful. Nevertheless the Reorganization Law is a very important figure in the Polish commercial law. Reorganization proceedings seriously differ from bankruptcy proceedings

  2. 对侧外周神经移位到损伤手臂引起的体感皮层功能动态重组%Dynamically Functional Reorganization in Somatosensory Cortex Induced by The Contralateral Peripheral Nerve Transfer to an Injured Arm

    Institute of Scientific and Technical Information of China (English)

    娄莉; 顾玉东; 寿天德

    2006-01-01

    单侧肢体的外周神经损伤通常导致对侧体感皮层的功能重组.然而,接受了对侧颈7(C7)外周神经移位手术治疗单侧手臂臂丛全撕脱的病人,在术后早期当其患手被触摸时,只在其健手产生感觉.在术后晚期,病人才逐渐恢复其患手和健手的正常、独立的功能.我们在模拟对侧颈7(C7)外周神经移位手术病例的大鼠模型上,用记录体感诱发电位的方法研究了患手和健手的体感代表区.患手的体感和运动功能由于C7神经的再生而逐渐恢复.术后第5个月始,13只大鼠患手的体感代表区只出现在其同侧的皮层,同时患手和健手的代表区在该皮层内是高度重叠的(除掉一个例外),虽然刺激它们产生的体感诱发电位的潜伏期和反应幅度有很大的不同.结果表明,移位到患手的对侧外周神经能够导致同侧体感皮层动态的功能重组,提示身体另侧感觉输入的介入激发了大脑显著的可塑性.%Peripheral nerve injury of a limb usually causes functional reorganization of the contralateral somatosensory cortex.However, the patients with an operation of the contralateral seventh cervical nerve (C7) transfer to an injured arm with brachial plexus root avulsions usually have the sole tactile sensibility of the healthy hand when the injured hand is touched at the early stage after the operation. Then, at later stage they gradually get normal sense from the injured and the normal hands independently. Mimicked the process in a rat model based on the above operation, representations of the injured forepaw and the healthy forepaw in the somatosensory cortex were studied by means of somatosensory evoked potential (SEP) recording. Somatosensory function shown in SEP response amplitude and peak latency of the injured forepaw gradually recovered with time after the operation due to the contralateral C7 regeneration toward the injured limb, accompanied with the recovery process of limb movement

  3. Small gray matter volume in orbitofrontal cortex in Prader-Willi syndrome: a voxel-based MRI study.

    Science.gov (United States)

    Ogura, Kaeko; Fujii, Toshikatsu; Abe, Nobuhito; Hosokai, Yoshiyuki; Shinohara, Mayumi; Takahashi, Shoki; Mori, Etsuro

    2011-07-01

    Prader-Willi syndrome (PWS) is a genetically determined neurodevelopmental disorder presenting with behavioral symptoms including hyperphagia, disinhibition, and compulsive behavior. The behavioral problems in individuals with PWS are strikingly similar to those in patients with frontal pathologies, particularly those affecting the orbitofrontal cortex (OFC). However, neuroanatomical abnormalities in the frontal lobe have not been established in PWS. The aim of this study was to look, using volumetric analysis, for morphological changes in the frontal lobe, especially the OFC, of the brains of individuals with PWS. Twelve adults with PWS and 13 age- and gender-matched control subjects participated in structural magnetic resonance imaging (MRI) scans. The whole-brain images were segmented and normalized to a standard stereotactic space. Regional gray matter volumes were compared between the PWS group and the control group using voxel-based morphometry. The PWS subjects showed small gray-matter volume in several regions, including the OFC, caudate nucleus, inferior temporal gyrus, precentral gyrus, supplementary motor area, postcentral gyrus, and cerebellum. The small gray-matter volume in the OFC remained significant in a separate analysis that included total gray matter volume as a covariate. These preliminary findings suggest that the neurobehavioral symptoms in individuals with PWS are related to structural brain abnormalities in these areas.

  4. Effects of the charge-transfer reorganization energy on the open-circuit voltage in small-molecular bilayer organic photovoltaic devices: comparison of the influence of deposition rates of the donor.

    Science.gov (United States)

    Lee, Chih-Chien; Su, Wei-Cheng; Chang, Wen-Chang

    2016-05-14

    The theoretical maximum of open-circuit voltage (VOC) of organic photovoltaic (OPV) devices has yet to be determined, and its origin remains debated. Here, we demonstrate that VOC of small-molecule OPV devices can be improved by controlling the deposition rate of a donor without changing the interfacial energy gap at the donor/acceptor interface. The measurement of external quantum efficiency and electroluminescence spectra facilitates the observation of the existence of charge transfer (CT) states. A simplified approach by reusing the reciprocity relationship for obtaining the properties of the CT states is proposed without introducing complex techniques. We compare experimental and fitting results and propose that reorganization energy is the primary factor in determining VOC instead of either the CT energy or electronic coupling term in bilayer OPV devices. Atomic force microscopy images indicate a weak molecular aggregation when a higher deposition rate is used. The results of temperature-dependent measurements suggest the importance of molecular stacking for the CT properties.

  5. A Novel Naphthalimide Compound Restores p53 Function in Non-small Cell Lung Cancer by Reorganizing the Bak·Bcl-xl Complex and Triggering Transcriptional Regulation.

    Science.gov (United States)

    Zhang, Guohai; An, Yunfeng; Lu, Xing; Zhong, Hui; Zhu, Yanhong; Wu, Yiming; Ma, Feng'e; Yang, Jingmei; Liu, Yancheng; Zhou, Zuping; Peng, Yan; Chen, Zhenfeng

    2016-02-19

    p53 inactivation is a hallmark in non-small-cell lung cancer (NSCLC). It is therefore highly desirable to develop tumor-specific treatment for NSCLC therapy by restoring p53 function. Herein, a novel naphthalimide compound, NA-17, was identified as a promising drug candidate in view of both its anticancer activity and mechanism of action. NA-17 exhibited strong anticancer activity on a broad range of cancer cell lines but showed low toxicity to normal cell lines, such as HL-7702 and WI-38. Moreover, NA-17 showed p53-dependent inhibition selectivity in different NSCLC cell lines due to the activation state of endogenous p53 in the background level. Further studies revealed that NA-17 caused cell cycle arrest at the G1 phase, changed cell size, and induced apoptosis and cell death by increasing the proportion of sub-G1 cells. Molecular mechanism studies suggested that targeted accumulation of phospho-p53 in mitochondria and nuclei induced by NA-17 resulted in activation of Bak and direct binding of phospho-p53 to the target DNA sequences, thereby evoking cell apoptosis and cell cycle arrest and eventually leading to irreversible cancer cell inhibition. This work provided new insights into the molecular interactions and anticancer mechanisms of phospho-p53-dependent naphthalimide compounds.

  6. Egypt/FOF reorganize.

    Science.gov (United States)

    1984-01-01

    In Egypt, both the national family planning program and the privately operated social marketing program, Family of the Future (FOF), are currently being reorganized. The Population and Family Planning Board, orginally charged with the responsibility of overseeing the national family planning program, was replaced by the newly created National Council. The reasons for the change and the type of program changes which will ensue from this organizational change are unclear. The FOF recently adopted a new management organizational structure, implemented a computerized management and information system, and initiated a staff training program. The management of the program's product line is now divided into 3 sections. There are separate sections for IUDs, barrier methods, and hormonal methods. Each section is responsible for developing a marketing plan for its products and overseeing the distribution of its products. The management staff is now provided with management skills training. To date, 9 managers have received training in management techniques in the US at George Washington University. Personal computers are being installed at the FOF office in Cairo. The system will be used to keep tract of inventory, volunteer activities, and product distribution and to handle accounting procedures. These innovations are expected to facilitate the handling of planned changes in FOF's product line. FOF will begin selling surgical gloves, as a supplemental item for its currently marketed IUD kit, and pregnancy testing kits for use by physicians and hospitals. Other anticipated introductions include Depo Provera, an injectable contraceptive, the new Ortho vaginal tablet which will replace the currently marketed Annan vaginal tablet, and possibly, the implant contraceptive, Norplant. Triton is currently under contract with the US Agency for International Development to provide technical assistance for the FOF program. This contract is due to expire in December, 1984, and a

  7. Expression of microRNAs and other small RNAs in prefrontal cortex in schizophrenia, bipolar disorder and depressed subjects.

    Directory of Open Access Journals (Sweden)

    Neil R Smalheiser

    Full Text Available Because of the role played by miRNAs in post-transcriptional regulation of an array of genes, their impact in neuropsychiatric disease pathophysiology has increasingly been evident. In the present study, we assessed microRNA expression in prefrontal cortex (Brodmann area 10 of a well-characterized cohort of major depressed, bipolar, and schizophrenia subjects (obtained from Stanley Neuropathology Consortium; n = 15 in each group, using high throughput RT-PCR plates. Discrete miRNA alterations were observed in all disorders, as well as in suicide subjects (pooled across diagnostic categories compared to all non-suicide subjects. The changes in the schizophrenia group were partially similar to those in the bipolar group, but distinct from changes in depression and suicide. Intriguingly, those miRNAs which were down-regulated in the schizophrenia group tended to be synaptically enriched, whereas up-regulated miRNAs tended not to be. To follow this up, we purified synaptosomes from pooled samples of the schizophrenia vs. control groups and subjected them to Illumina deep sequencing. There was a significant loss of small RNA expression in schizophrenia synaptosomes only for certain sequence lengths within the miRNA range. Moreover, 73 miRNAs were significantly down-regulated whereas only one was up-regulated. Strikingly, across all expressed miRNAs in synaptosomes, there was a significant inverse correlation between the fold-change of a given miRNA seen in schizophrenia and its synaptic enrichment ratio observed in controls. Thus, synaptic miRNAs tended to be down-regulated in schizophrenia, and the more highly synaptically enriched miRNAs tended to show greater down-regulation. These findings point to some deficit in miRNA biogenesis, transport, processing or turnover in schizophrenia that is selective for the synaptic compartment. A novel class of ncRNA-derived small RNAs, shown to be strongly induced during an early phase of learning in mouse

  8. Expression of microRNAs and other small RNAs in prefrontal cortex in schizophrenia, bipolar disorder and depressed subjects.

    Science.gov (United States)

    Smalheiser, Neil R; Lugli, Giovanni; Zhang, Hui; Rizavi, Hooriyah; Cook, Edwin H; Dwivedi, Yogesh

    2014-01-01

    Because of the role played by miRNAs in post-transcriptional regulation of an array of genes, their impact in neuropsychiatric disease pathophysiology has increasingly been evident. In the present study, we assessed microRNA expression in prefrontal cortex (Brodmann area 10) of a well-characterized cohort of major depressed, bipolar, and schizophrenia subjects (obtained from Stanley Neuropathology Consortium; n = 15 in each group), using high throughput RT-PCR plates. Discrete miRNA alterations were observed in all disorders, as well as in suicide subjects (pooled across diagnostic categories) compared to all non-suicide subjects. The changes in the schizophrenia group were partially similar to those in the bipolar group, but distinct from changes in depression and suicide. Intriguingly, those miRNAs which were down-regulated in the schizophrenia group tended to be synaptically enriched, whereas up-regulated miRNAs tended not to be. To follow this up, we purified synaptosomes from pooled samples of the schizophrenia vs. control groups and subjected them to Illumina deep sequencing. There was a significant loss of small RNA expression in schizophrenia synaptosomes only for certain sequence lengths within the miRNA range. Moreover, 73 miRNAs were significantly down-regulated whereas only one was up-regulated. Strikingly, across all expressed miRNAs in synaptosomes, there was a significant inverse correlation between the fold-change of a given miRNA seen in schizophrenia and its synaptic enrichment ratio observed in controls. Thus, synaptic miRNAs tended to be down-regulated in schizophrenia, and the more highly synaptically enriched miRNAs tended to show greater down-regulation. These findings point to some deficit in miRNA biogenesis, transport, processing or turnover in schizophrenia that is selective for the synaptic compartment. A novel class of ncRNA-derived small RNAs, shown to be strongly induced during an early phase of learning in mouse, is also

  9. Rural School District Reorganization on the Great Plains.

    Science.gov (United States)

    Bryant, Miles

    2002-01-01

    Rural school district reorganization and school consolidation are put into perspective by reviewing the large population increases that fueled small-school growth in the Great Plains, 1870-1930. Since the Dust Bowl and Great Depression, population losses, improvements in transportation, and arguments advocating economies of scale and increased…

  10. Cortical Development, Plasticity and Re-Organization in Children with Cochlear Implants

    Science.gov (United States)

    Sharma, Anu; Nash, Amy A.; Dorman, Michael

    2009-01-01

    A basic tenet of developmental neurobiology is that certain areas of the cortex will re-organize, if appropriate stimulation is withheld for long periods. Stimulation must be delivered to a sensory system within a narrow window of time (a sensitive period) if that system is to develop normally. In this article, we will describe age cut-offs for a…

  11. Unilateral hearing during development: hemispheric specificity in plastic reorganizations

    Directory of Open Access Journals (Sweden)

    Andrej eKral

    2013-11-01

    Full Text Available The present study investigates the hemispheric contributions of neuronal reorganization following early single-sided hearing (unilateral deafness. The experiments were performed on ten cats from our colony of deaf white cats. Two were identified in early hearing screening as unilaterally congenitally deaf. The remaining eight were bilaterally congenitally deaf, unilaterally implanted at different ages with a cochlear implant. Implanted animals were chronically stimulated using a single-channel portable signal processor for two to five months. Microelectrode recordings were performed at the primary auditory cortex under stimulation at the hearing and deaf ear with bilateral cochlear implants. Local field potentials (LFPs were compared at the cortex ipsilateral and contralateral to the hearing ear. The focus of the study was on the morphology and the onset latency of the LFPs. The data revealed that effects of hearing experience were more pronounced when stimulating the hearing ear. With respect to morphology of LFPs, pronounced hemisphere-specific effects were observed. Morphology of amplitude-normalized LFPs for stimulation of the deaf and the hearing ear was similar for responses recorded at the same hemisphere. However, when comparisons were performed between the hemispheres, the morphology was more dissimilar even though the same ear was stimulated. This demonstrates hemispheric specificity of some cortical adaptations irrespective of the ear stimulated. The results suggest a specific adaptation process at the hemisphere ipsilateral to the hearing ear, involving specific (down-regulated inhibitory mechanisms not found in the contralateral hemisphere. Finally, onset latencies revealed that the sensitive period for the cortex ipsilateral to the hearing ear is shorter than that for the contralateral cortex. Unilateral hearing experience leads to a functionally-asymmetric brain with different neuronal reorganizations and different sensitive

  12. A new cellular stress response that triggers centriolar satellite reorganization and ciliogenesis

    DEFF Research Database (Denmark)

    Villumsen, Bine H; Danielsen, Jannie R; Povlsen, Lou;

    2013-01-01

    Centriolar satellites are small, granular structures that cluster around centrosomes, but whose biological function and regulation are poorly understood. We show that centriolar satellites undergo striking reorganization in response to cellular stresses such as UV radiation, heat shock...

  13. A theoretical description of charge reorganization energies in molecular organic P-type semiconductors.

    Science.gov (United States)

    Brückner, Charlotte; Engels, Bernd

    2016-06-05

    Charge transport properties of materials composed of small organic molecules are important for numerous optoelectronic applications. A material's ability to transport charges is considerably influenced by the charge reorganization energies of the composing molecules. Hence, predictions about charge-transport properties of organic materials deserve reliable statements about these charge reorganization energies. However, using density functional theory which is mostly used for the predictions, the computed reorganization energies depend strongly on the chosen functional. To gain insight, a benchmark of various density functionals for the accurate calculation of charge reorganization energies is presented. A correlation between the charge reorganization energies and the ionization potentials is found which suggests applying IP-tuning to obtain reliable values for charge reorganization energies. According to benchmark investigations with IP-EOM-CCSD single-point calculations, the tuned functionals provide indeed more reliable charge reorganization energies. Among the standard functionals, ωB97X-D and SOGGA11X yield accurate charge reorganization energies in comparison with IP-EOM-CCSD values. © 2016 Wiley Periodicals, Inc.

  14. Firm Reorganization : Social Control or Social Contract?

    NARCIS (Netherlands)

    Aalbers, Hendrik Leendert; Dolfsma, Wilfred; Blinde-Leerentveld, Rowan

    2014-01-01

    Firm reorganizations deeply affect employees. Management can reorganize in different ways, focusing on costs or acknowledging the involvement of employees. The latter implies following a social contract that complements incomplete (formal) labor contracts. Little is known about how the way in which

  15. Firm Reorganization: Social Control or Social Contract

    NARCIS (Netherlands)

    Aalbers, H.L.; Dolfsma, W.A.; Blinde-Leerentveld, R.

    2014-01-01

    Firm reorganizations deeply affect employees. Management can reorganize in different ways, focusing on costs or acknowledging the involvement of employees. The latter implies following a social contract that complements incomplete (formal) labor contracts. Little is known about how the way in which

  16. NMDAR-regulated dynamics of layer 4 neuronal dendrites during thalamocortical reorganization in neonates.

    Science.gov (United States)

    Mizuno, Hidenobu; Luo, Wenshu; Tarusawa, Etsuko; Saito, Yoshikazu M; Sato, Takuya; Yoshimura, Yumiko; Itohara, Shigeyoshi; Iwasato, Takuji

    2014-04-16

    Thalamocortical (TC) connectivity is reorganized by thalamic inputs during postnatal development; however, the dynamic characteristics of TC reorganization and the underlying mechanisms remain unexplored. We addressed this question using dendritic refinement of layer 4 (L4) stellate neurons in mouse barrel cortex (barrel cells) as a model; dendritic refinement of L4 neurons is a critical component of TC reorganization through which postsynaptic L4 neurons acquire their dendritic orientation toward presynaptic TC axon termini. Simultaneous labeling of TC axons and individual barrel cell dendrites allowed in vivo time-lapse imaging of dendritic refinement in the neonatal cortex. The barrel cells reinforced the dendritic orientation toward TC axons by dynamically moving their branches. In N-methyl-D-aspartate receptor (NMDAR)-deficient barrel cells, this dendritic motility was enhanced, and the orientation bias was not reinforced. Our data suggest that L4 neurons have "fluctuating" dendrites during TC reorganization and that NMDARs cell autonomously regulate these dynamics to establish fine-tuned circuits.

  17. Shaping Early Reorganization of Neural Networks Promotes Motor Function after Stroke.

    OpenAIRE

    2016-01-01

    Neural plasticity is a major factor driving cortical reorganization after stroke. We here tested whether repetitively enhancing motor cortex plasticity by means of intermittent theta-burst stimulation (iTBS) prior to physiotherapy might promote recovery of function early after stroke. Functional magnetic resonance imaging (fMRI) was used to elucidate underlying neural mechanisms. Twenty-six hospitalized, first-ever stroke patients (time since stroke: 1–16 days) with hand motor deficits were e...

  18. Perilesional reorganization of somatosensory function following traumatic cortical contusion A case report

    Institute of Scientific and Technical Information of China (English)

    Mi Young Lee; Sung Ho Jang

    2011-01-01

    The present study reports on a 23-year-old male patient with somatosensory dysfunction of the left hand following cortical contusion. His somatosensory dysfunction recovered to a nearly normal state at 6 months after injury. Functional MRI results demonstrated that the contralateral primary sensorimotor cortex centered on the primary somatosensroy cortex was activated during touch stimulation of the patient's right hand and either hand of control subjects. By contrast, the anterior area of the lesion centered on the precentral knob in the right hemisphere was activated during touch stimulation of the left hand. These findings show that the somatosensory function of the affected hand appears to have been recovered by the somatosensory cortex reorganizing into the anterior area of the contused primary somatosensory cortex.

  19. Dynamic Reorganization and Correlation among Lipid Raft Components.

    Science.gov (United States)

    Lozano, Mónica M; Hovis, Jennifer S; Moss, Frank R; Boxer, Steven G

    2016-08-10

    Lipid rafts are widely believed to be an essential organizational motif in cell membranes. However, direct evidence for interactions among lipid and/or protein components believed to be associated with rafts is quite limited owing, in part, to the small size and intrinsically dynamic interactions that lead to raft formation. Here, we exploit the single negative charge on the monosialoganglioside GM1, commonly associated with rafts, to create a gradient of GM1 in response to an electric field applied parallel to a patterned supported lipid bilayer. The composition of this gradient is visualized by imaging mass spectrometry using a NanoSIMS. Using this analytical method, added cholesterol and sphingomyelin, both neutral and not themselves displaced by the electric field, are observed to reorganize with GM1. This dynamic reorganization provides direct evidence for an attractive interaction among these raft components into some sort of cluster. At steady state we obtain an estimate for the composition of this cluster.

  20. Farthest First Clustering in Links Reorganization

    Directory of Open Access Journals (Sweden)

    Deepshree A. Vadeyar

    2014-07-01

    Full Text Available Website can be easily design but to efficient user navigation is not a easy task since user behavior is keep changing and developer view is quite different from what user wants, so to improve navigation one way is reorganization of website structure. For reorganization here proposed strategy is farthest first traversal clustering algorithm perform clustering on two numeric parameters and for finding frequent traversal path of user Apriori algorithm is used. Our aim is to perform reorganization with fewer changes in website structure.

  1. Influence of peripheral nerve stimulation on the responses in small hand muscles to transcranial magnetic cortex stimulation.

    Science.gov (United States)

    Date, M; Schmid, U D; Hess, C W; Schmid, J

    1991-01-01

    The influence of afferent median nerve stimulation on the responses of small hand muscles (CMAPs) to cortical stimulation (CortStim) was investigated by applying short stimulus trains to the median nerve at the wrist and slightly suprathreshold magnetic stimuli to the scalp. Train stimulus frequency (TSF), train stimulus intensity (TSI), and train onset (TO) in relation to the CortStim were varied. Amplitudes and latencies of CMAPs were compared with those obtained by CortStim alone. When applying short trains of 10 msec duration, of 300/sec-400/sec TSF, and of threshold or supramaximal intensity for motor fibers, both facilitatory and inhibitory effects on the responses to CortStim were achieved depending on the timing of the train onset. With a TO of 8-10 msec before CortStim, mean amplitudes of CMAPs were enhanced 3-10 times; mean amplitudes reached up to 20 times the baseline values when the TO was greater than 45 msec before CortStim. With a TO of 15-35 msec before CortStim, amplitudes were diminished below control values. No systematic changes in latency were noted with TO of 8-10 msec, but when the TO was 45-60 msec before CortStim the latencies of CMAPs were 1.5-3 msec shorter than baseline latencies. With afferent stimuli that were subthreshold for motor fibers facilitation only occurred when the TO was about 45 msec before CortStim. The differences were statistically significant (Wilcoxon-Mann-Whitney Test). This biphasic pattern of facilitation and inhibition probably reflects spinal and supraspinal reflex phenomena mediated by spindle receptor and various cutaneous afferents.

  2. Differential reorganization of fusiform gyrus in two types of alexia after stroke.

    Science.gov (United States)

    Pyun, Sung-Bom; Sohn, Hyo-Jeong; Jung, Jae-Bum; Nam, Kichun

    2007-10-01

    Lesions affecting the left fusiform gyrus (FG) commonly result in dyslexia and recovery largely depends on efficient reorganization of the reading network. We performed a follow-up fMRI study to elucidate the reorganization patterns of the FG according to the recovery of reading ability in two patients (MH with pure alexia and KM with alexia with agraphia) after stroke involving the left FG. Initially, MH was an effortful letter-by-letter (LBL) reader, and she improved to become a proficient LBL reader. The initial fMRI results showed scattered activation on occipital and ventral temporal cortex during reading, which was localized to right FG in the follow-up study. KM's severe alexia with agraphia did not improve, even after 6 months had passed since the onset of the alexia. The initial and follow-up fMRI results showed no significant activation in the bilateral FG or central higher language areas during word reading. Our results suggest that the reorganization of the FG is different according to the type of alexia and the amount of clinical recovery in each patient. Also, the successful reorganization of the visual component of reading in the right FG is responsible for the recovery of LBL reading in pure alexia.

  3. Shareholders, creditors approve utility reorganization plan

    Energy Technology Data Exchange (ETDEWEB)

    1990-04-12

    Shareholders and all classes of secured creditors of Public Service Company of New Hampshire voted overwhelmingly last month to approve Northeast Utilities' Chapter 11 reorganization plan for PSNH, the utility announced. PSNH filed for bankruptcy protection in January 1988. Under the reorganization plan, Connecticut-based NU would acquire the utility for $2.3 billion. While PSNH's preferred and common stockholders voted to accept the proposal, holders of warrants to purchase PSNH common stock rejected the plan. Except for the votes of a group of independent power producers, PSNH's unsecured creditors also voted to accept the plan.

  4. Metalloproteinase inhibition prevents inhibitory synapse reorganization and seizure genesis.

    Science.gov (United States)

    Pollock, Emily; Everest, Michelle; Brown, Arthur; Poulter, Michael O

    2014-10-01

    The integrity and stability of interneurons in a cortical network are essential for proper network function. Loss of interneuron synaptic stability and precise organization can lead to disruptions in the excitation/inhibition balance, a characteristic of epilepsy. This study aimed to identify alterations to the GABAergic interneuron network in the piriform cortex (PC: a cortical area believed to be involved in the development of seizures) after kindling-induced seizures. Immunohistochemistry was used to mark perineuronal nets (PNNs: structures in the extracellular matrix that provide synaptic stability and restrict reorganization of inhibitory interneurons) and interneuron nerve terminals in control and kindled tissues. We found that PNNs were significantly decreased around parvalbumin-positive interneurons after the induction of experimental epilepsy. Additionally, we found layer-specific increases in GABA release sites originating from calbindin, calretinin, and parvalbumin interneurons, implying that there is a re-wiring of the interneuronal network. This increase in release sites was matched by an increase in GABAergic post-synaptic densities. We hypothesized that the breakdown of the PNN could be due to the activity of matrix metalloproteinases (MMP) and that the prevention of PNN breakdown may reduce the rewiring of interneuronal circuits and suppress seizures. To test this hypothesis we employed doxycycline, a broad spectrum MMP inhibitor, to stabilize PNNs in kindled rats. We found that doxycycline prevented PNN breakdown, re-organization of the inhibitory innervation, and seizure genesis. Our observations indicate that PNN degradation may be necessary for the development of seizures by facilitating interneuron plasticity and increased GABAergic activity.

  5. Functional Cortical and Cerebellar Reorganization in a Case of Moyamoya Disease

    Science.gov (United States)

    Calabrò, Rocco S.; Bramanti, Placido; Baglieri, Annalisa; Corallo, Francesco; De Luca, Rosaria; De Salvo, Simona

    2015-01-01

    Background: Functional studies have been previous reported in stroke patients, but no studies of functional magnetic resonance imaging have been performed in Moyamoya disease. Objective: To assess the cortical and cerebellar reorganization in a moyamoya patient. Methods: We reported a case of a patient suffering from moyamoya disease, undergoing a neuropsychological assessment, a neurocognitive rehabilitative treatment, an electroencephalogram evaluation, and a functional magnetic resonance imaging examination. Results: The subject showed a cognitive impairment, a slow electroencephalogram activity, and the ipsi- and controlateral motor cortex and cerebellar functional magnetic resonance imaging activation. Conclusions: This is the first functional magnetic resonance imaging case study reported in moyamoya disease. We showed a cortical reorganization, which could play an important role in clinical evaluation and motor recovery. The cerebellar activation, showed after cognitive and motor rehabilitation, could support the idea that the cerebellum contains several cognitive-related subregions involved in different functional networks in moyamoya disease. PMID:25852976

  6. JUDICIAL REORGANIZATION – SOLUTION FOR CRISIS PERIODS

    Directory of Open Access Journals (Sweden)

    MARINA UHER

    2012-05-01

    Full Text Available Currently in the Romanian economic landscape the insolvency phenomenon began to be increasingly better known to the business community first through the impact on business partners from different areas of the industry, and then through the personal experience. For creditors supporting a reorganization plan with real prospects of recovery and covering claims proves to be advantageous especially in current market conditions.

  7. Spatial language processing in the blind: evidence for a supramodal representation and cortical reorganization.

    Directory of Open Access Journals (Sweden)

    Marijn E Struiksma

    Full Text Available Neuropsychological and imaging studies have shown that the left supramarginal gyrus (SMG is specifically involved in processing spatial terms (e.g. above, left of, which locate places and objects in the world. The current fMRI study focused on the nature and specificity of representing spatial language in the left SMG by combining behavioral and neuronal activation data in blind and sighted individuals. Data from the blind provide an elegant way to test the supramodal representation hypothesis, i.e. abstract codes representing spatial relations yielding no activation differences between blind and sighted. Indeed, the left SMG was activated during spatial language processing in both blind and sighted individuals implying a supramodal representation of spatial and other dimensional relations which does not require visual experience to develop. However, in the absence of vision functional reorganization of the visual cortex is known to take place. An important consideration with respect to our finding is the amount of functional reorganization during language processing in our blind participants. Therefore, the participants also performed a verb generation task. We observed that only in the blind occipital areas were activated during covert language generation. Additionally, in the first task there was functional reorganization observed for processing language with a high linguistic load. As the visual cortex was not specifically active for spatial contents in the first task, and no reorganization was observed in the SMG, the latter finding further supports the notion that the left SMG is the main node for a supramodal representation of verbal spatial relations.

  8. Spatial Language Processing in the Blind: Evidence for a Supramodal Representation and Cortical Reorganization

    Science.gov (United States)

    Struiksma, Marijn E.; Noordzij, Matthijs L.; Neggers, Sebastiaan F. W.; Bosker, Wendy M.; Postma, Albert

    2011-01-01

    Neuropsychological and imaging studies have shown that the left supramarginal gyrus (SMG) is specifically involved in processing spatial terms (e.g. above, left of), which locate places and objects in the world. The current fMRI study focused on the nature and specificity of representing spatial language in the left SMG by combining behavioral and neuronal activation data in blind and sighted individuals. Data from the blind provide an elegant way to test the supramodal representation hypothesis, i.e. abstract codes representing spatial relations yielding no activation differences between blind and sighted. Indeed, the left SMG was activated during spatial language processing in both blind and sighted individuals implying a supramodal representation of spatial and other dimensional relations which does not require visual experience to develop. However, in the absence of vision functional reorganization of the visual cortex is known to take place. An important consideration with respect to our finding is the amount of functional reorganization during language processing in our blind participants. Therefore, the participants also performed a verb generation task. We observed that only in the blind occipital areas were activated during covert language generation. Additionally, in the first task there was functional reorganization observed for processing language with a high linguistic load. As the visual cortex was not specifically active for spatial contents in the first task, and no reorganization was observed in the SMG, the latter finding further supports the notion that the left SMG is the main node for a supramodal representation of verbal spatial relations. PMID:21935391

  9. 17 CFR 250.63 - Approval of reorganization fees.

    Science.gov (United States)

    2010-04-01

    ... (CONTINUED) GENERAL RULES AND REGULATIONS, PUBLIC UTILITY HOLDING COMPANY ACT OF 1935 Solicitations and Reorganizations § 250.63 Approval of reorganization fees. All fees, expenses and remuneration, whether interim or...

  10. 13 CFR 108.470 - SBA approval of merger, consolidation, or reorganization of NMVC Company.

    Science.gov (United States)

    2010-01-01

    ..., consolidation, or reorganization of NMVC Company. 108.470 Section 108.470 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION NEW MARKETS VENTURE CAPITAL (âNMVCâ) PROGRAM Changes in Ownership, Structure, or Control Change in Structure of Nmvc Company § 108.470 SBA approval of merger, consolidation,...

  11. Visual Cross-Modal Re-Organization in Children with Cochlear Implants.

    Directory of Open Access Journals (Sweden)

    Julia Campbell

    Full Text Available Visual cross-modal re-organization is a neurophysiological process that occurs in deafness. The intact sensory modality of vision recruits cortical areas from the deprived sensory modality of audition. Such compensatory plasticity is documented in deaf adults and animals, and is related to deficits in speech perception performance in cochlear-implanted adults. However, it is unclear whether visual cross-modal re-organization takes place in cochlear-implanted children and whether it may be a source of variability contributing to speech and language outcomes. Thus, the aim of this study was to determine if visual cross-modal re-organization occurs in cochlear-implanted children, and whether it is related to deficits in speech perception performance.Visual evoked potentials (VEPs were recorded via high-density EEG in 41 normal hearing children and 14 cochlear-implanted children, aged 5-15 years, in response to apparent motion and form change. Comparisons of VEP amplitude and latency, as well as source localization results, were conducted between the groups in order to view evidence of visual cross-modal re-organization. Finally, speech perception in background noise performance was correlated to the visual response in the implanted children.Distinct VEP morphological patterns were observed in both the normal hearing and cochlear-implanted children. However, the cochlear-implanted children demonstrated larger VEP amplitudes and earlier latency, concurrent with activation of right temporal cortex including auditory regions, suggestive of visual cross-modal re-organization. The VEP N1 latency was negatively related to speech perception in background noise for children with cochlear implants.Our results are among the first to describe cross modal re-organization of auditory cortex by the visual modality in deaf children fitted with cochlear implants. Our findings suggest that, as a group, children with cochlear implants show evidence of visual cross

  12. From network structure to network reorganization: implications for adult neurogenesis

    Science.gov (United States)

    Schneider-Mizell, Casey M.; Parent, Jack M.; Ben-Jacob, Eshel; Zochowski, Michal R.; Sander, Leonard M.

    2010-12-01

    Networks can be dynamical systems that undergo functional and structural reorganization. One example of such a process is adult hippocampal neurogenesis, in which new cells are continuously born and incorporate into the existing network of the dentate gyrus region of the hippocampus. Many of these introduced cells mature and become indistinguishable from established neurons, joining the existing network. Activity in the network environment is known to promote birth, survival and incorporation of new cells. However, after epileptogenic injury, changes to the connectivity structure around the neurogenic niche are known to correlate with aberrant neurogenesis. The possible role of network-level changes in the development of epilepsy is not well understood. In this paper, we use a computational model to investigate how the structural and functional outcomes of network reorganization, driven by addition of new cells during neurogenesis, depend on the original network structure. We find that there is a stable network topology that allows the network to incorporate new neurons in a manner that enhances activity of the persistently active region, but maintains global network properties. In networks having other connectivity structures, new cells can greatly alter the distribution of firing activity and destroy the initial activity patterns. We thus find that new cells are able to provide focused enhancement of network only for small-world networks with sufficient inhibition. Network-level deviations from this topology, such as those caused by epileptogenic injury, can set the network down a path that develops toward pathological dynamics and aberrant structural integration of new cells.

  13. Active biopolymers confer fast reorganization kinetics.

    Science.gov (United States)

    Swanson, Douglas; Wingreen, Ned S

    2011-11-18

    Many cytoskeletal biopolymers are "active," consuming energy in large quantities. In this Letter, we identify a fundamental difference between active polymers and passive, equilibrium polymers: for equal mean lengths, active polymers can reorganize faster than equilibrium polymers. We show that equilibrium polymers are intrinsically limited to linear scaling between mean lifetime (or mean first-passage time, or MFPT) and mean length, MFPT∼, by analogy to 1D Potts models. By contrast, we present a simple active-polymer model that improves upon this scaling, such that MFPT∼(1/2). Since, to be biologically useful, structural biopolymers must typically be many monomers long yet respond dynamically to the needs of the cell, the difference in reorganization kinetics may help to justify the active polymers' greater energy cost.

  14. Active Polymers Confer Fast Reorganization Kinetics

    CERN Document Server

    Swanson, Douglas

    2011-01-01

    Many cytoskeletal biopolymers are "active," consuming energy in large quantities. In this Letter, we identify a fundamental difference between active polymers and passive, equilibrium polymers: for equal mean lengths, active polymers can reorganize faster than equilibrium polymers. We show that equilibrium polymers are intrinsically limited to linear scaling between mean lifetime and mean length, MFPT ~ , by analogy to 1-d Potts models. By contrast, we present a simple active-polymer model that improves upon this scaling, such that MFPT ~ ^{1/2}. Since to be biologically useful, structural biopolymers must typically be many monomers long, yet respond dynamically to the needs of the cell, the difference in reorganization kinetics may help to justify active polymers' greater energy cost. PACS numbers: 87.10.Ed, 87.16.ad, 87.16.Ln

  15. Reorganizing and restructuring the human resources function

    OpenAIRE

    Alexandrina Mirela, Stan

    2010-01-01

    To determine what kind of skills (internal or external) of human resources are adequate organization can use human resources audit. Audit is an action guide that provides step by step consistency of human resources activities within the organization with legal regulations and informal practices. This paper aims to highlight the importance of human resources audit which is an essential activity and is basis for the reorganization and restructuring of human resources function.

  16. Local awakening: regional reorganizations of brain oscillations after sleep.

    Science.gov (United States)

    Tsai, Pei-Jung; Chen, Sharon Chia-Ju; Hsu, Chun-Yao; Wu, Changwei W; Wu, Yu-Chin; Hung, Ching-Sui; Yang, Albert C; Liu, Po-Yu; Biswal, Bharat; Lin, Ching-Po

    2014-11-15

    Brain functions express rhythmic fluctuations accompanied by sleep and wakefulness each day, but how sleep regulates brain rhythms remains unclear. Following the dose-dependent local sleep concept, two succeeding questions emerge: (1) is the sleep regulation a network-specific process; and (2) is the awakening state dependent on the previous sleep stages? To answer the questions, we conducted simultaneous EEG and fMRI recordings over 22 healthy male participants, along pre-sleep, nocturnal sleep and awakening. Using paired comparisons between awakening and pre-sleep conditions, three scenarios of the regional specificity were demonstrated on awakening: (1) the default-mode and hippocampal networks maintained similar connectivity and spectral power; (2) the sensorimotor network presented reduced connectivity and spectral power; and (3) the thalamus demonstrated substantially enhanced connectivity to the neo-cortex with decreased spectral power. With regard to the stage effect, the deep sleep group had significant changes in both functional connectivity and spectral power on awakening, whereas the indices of light sleep group remained relatively quiescent after sleep. The phenomena implied that slow-wave sleep could be key to rebooting the BOLD fluctuations after sleep. In conclusion, the regional specificity and the stage effect were verified in support of the local awakening concept, indicating that sleep regulation leads to the reorganization of brain networks upon awakening.

  17. Cytoskeletal Reorganization Drives Mesenchymal Condensation and Regulates Downstream Molecular Signaling.

    Directory of Open Access Journals (Sweden)

    Poulomi Ray

    Full Text Available Skeletal condensation occurs when specified mesenchyme cells self-organize over several days to form a distinctive cartilage template. Here, we determine how and when specified mesenchyme cells integrate mechanical and molecular information from their environment, forming cartilage condensations in the pharyngeal arches of chick embryos. By disrupting cytoskeletal reorganization, we demonstrate that dynamic cell shape changes drive condensation and modulate the response of the condensing cells to Fibroblast Growth Factor (FGF, Bone Morphogenetic Protein (BMP and Transforming Growth Factor beta (TGF-β signaling pathways. Rho Kinase (ROCK-driven actomyosin contractions and Myosin II-generated differential cell cortex tension regulate these cell shape changes. Disruption of the condensation process inhibits the differentiation of the mesenchyme cells into chondrocytes, demonstrating that condensation regulates the fate of the mesenchyme cells. We also find that dorsal and ventral condensations undergo distinct cell shape changes. BMP signaling is instructive for dorsal condensation-specific cell shape changes. Moreover, condensations exhibit ventral characteristics in the absence of BMP signaling, suggesting that in the pharyngeal arches ventral morphology is the ground pattern. Overall, this study characterizes the interplay between cytoskeletal dynamics and molecular signaling in a self-organizing system during tissue morphogenesis.

  18. Age-related neural reorganization during spoken word recognition: the interaction of form and meaning.

    Science.gov (United States)

    Shafto, Meredith; Randall, Billi; Stamatakis, Emmanuel A; Wright, Paul; Tyler, L K

    2012-06-01

    Research on language and aging typically shows that language comprehension is preserved across the life span. Recent neuroimaging results suggest that this good performance is underpinned by age-related neural reorganization [e.g., Tyler, L. K., Shafto, M. A., Randall, B., Wright, P., Marslen-Wilson, W. D., & Stamatakis, E. A. Preserving syntactic processing across the adult life span: The modulation of the frontotemporal language system in the context of age-related atrophy. Cerebral Cortex, 20, 352-364, 2010]. The current study examines how age-related reorganization affects the balance between component linguistic processes by manipulating semantic and phonological factors during spoken word recognition in younger and older adults. Participants in an fMRI study performed an auditory lexical decision task where words varied in their phonological and semantic properties as measured by degree of phonological competition and imageability. Older adults had a preserved lexicality effect, but compared with younger people, their behavioral sensitivity to phonological competition was reduced, as was competition-related activity in left inferior frontal gyrus. This was accompanied by increases in behavioral sensitivity to imageability and imageability-related activity in left middle temporal gyrus. These results support previous findings that neural compensation underpins preserved comprehension in aging and demonstrate that neural reorganization can affect the balance between semantic and phonological processing.

  19. White matter reorganization and functional response after focal cerebral ischemia in the rat.

    Directory of Open Access Journals (Sweden)

    Chrystelle Po

    Full Text Available After stroke, the brain has shown to be able to achieve spontaneous functional recovery despite severe cerebral damage. This phenomenon is poorly understood. To address this issue, focal transient ischemia was induced by 60 min middle cerebral artery occlusion in Wistar rats. The evolution of stroke was followed using two magnetic resonance imaging modalities: diffusion spectrum imaging (acquired before, one and four weeks after stroke and functional magnetic resonance imaging (acquired before and five weeks after stroke. To confirm the imaging observations, immunohistochemical staining for myelin, astrocytes and macrophages/microglia was added. At four weeks after stroke, a focal alteration of the diffusion anisotropy was observed between the ipsilesional ventricle and the lesion area. Using tractography this perturbation was identified as reorganization of the ipsilesional internal capsule. Functional imaging at five weeks after ischemia demonstrated activation of the primary sensorimotor cortex in both hemispheres in all rats except one animal lacking a functional response in the ipsilesional cortex. Furthermore, fiber tracking showed a transhemispheric fiber connection through the corpus callosum, which-in the rat without functional recovery-was lost. Our study shows the influence of the internal capsule reorganization, combined with inter-hemispheric connections though the corpus callosum, on the functional activation of the brain from stroke. In conclusion, tractography opens a new door to non-invasively investigate the structural correlates of lack of functional recovery after stroke.

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

    Science.gov (United States)

    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.

  1. Microstructure of transcallosal motor fibers reflects type of cortical (re-)organization in congenital hemiparesis.

    Science.gov (United States)

    Juenger, Hendrik; Koerte, Inga K; Muehlmann, Marc; Mayinger, Michael; Mall, Volker; Krägeloh-Mann, Ingeborg; Shenton, Martha E; Berweck, Steffen; Staudt, Martin; Heinen, Florian

    2014-11-01

    Early unilateral brain lesions can lead to different types of corticospinal (re-)organization of motor networks. In one group of patients, the contralesional hemisphere exerts motor control not only over the contralateral non-paretic hand but also over the (ipsilateral) paretic hand, as the primary motor cortex is (re-)organized in the contralesional hemisphere. Another group of patients with early unilateral lesions shows "normal" contralateral motor projections starting in the lesioned hemisphere. We investigated how these different patterns of cortical (re-)organization affect interhemispheric transcallosal connectivity in patients with congenital hemiparesis. Eight patients with ipsilateral motor projections (group IPSI) versus 7 patients with contralateral motor projections (group CONTRA) underwent magnetic resonance diffusion tensor imaging (DTI). The corpus callosum (CC) was subdivided in 5 areas (I-V) in the mid-sagittal slice and volumetric information. The following diffusion parameters were calculated: fractional anisotropy (FA), trace, radial diffusivity (RD), and axial diffusivity (AD). DTI revealed significantly lower FA, increased trace and RD for group IPSI compared to group CONTRA in area III of the corpus callosum, where transcallosal motor fibers cross the CC. In the directly neighboring area IV, where transcallosal somatosensory fibers cross the CC, no differences were found for these DTI parameters between IPSI and CONTRA. Volume of callosal subsections showed significant differences for area II (connecting premotor cortices) and III, where group IPSI had lower volume. The results of this study demonstrate that the callosal microstructure in patients with congenital hemiparesis reflects the type of cortical (re-)organization. Early lesions disrupting corticospinal motor projections to the paretic hand consecutively affect the development or maintenance of transcallosal motor fibers. Copyright © 2014 European Paediatric Neurology Society

  2. Evolution of crossmodal reorganization of the voice area in cochlear-implanted deaf patients.

    Science.gov (United States)

    Rouger, Julien; Lagleyre, Sébastien; Démonet, Jean-François; Fraysse, Bernard; Deguine, Olivier; Barone, Pascal

    2012-08-01

    Psychophysical and neuroimaging studies in both animal and human subjects have clearly demonstrated that cortical plasticity following sensory deprivation leads to a brain functional reorganization that favors the spared modalities. In postlingually deaf patients, the use of a cochlear implant (CI) allows a recovery of the auditory function, which will probably counteract the cortical crossmodal reorganization induced by hearing loss. To study the dynamics of such reversed crossmodal plasticity, we designed a longitudinal neuroimaging study involving the follow-up of 10 postlingually deaf adult CI users engaged in a visual speechreading task. While speechreading activates Broca's area in normally hearing subjects (NHS), the activity level elicited in this region in CI patients is abnormally low and increases progressively with post-implantation time. Furthermore, speechreading in CI patients induces abnormal crossmodal activations in right anterior regions of the superior temporal cortex normally devoted to processing human voice stimuli (temporal voice-sensitive areas-TVA). These abnormal activity levels diminish with post-implantation time and tend towards the levels observed in NHS. First, our study revealed that the neuroplasticity after cochlear implantation involves not only auditory but also visual and audiovisual speech processing networks. Second, our results suggest that during deafness, the functional links between cortical regions specialized in face and voice processing are reallocated to support speech-related visual processing through cross-modal reorganization. Such reorganization allows a more efficient audiovisual integration of speech after cochlear implantation. These compensatory sensory strategies are later completed by the progressive restoration of the visuo-audio-motor speech processing loop, including Broca's area. Copyright © 2011 Wiley Periodicals, Inc.

  3. Visual Cortex Plasticity Following Peripheral Damage To The Visual System: fMRI Evidence.

    Science.gov (United States)

    Lemos, João; Pereira, Daniela; Castelo-Branco, Miguel

    2016-10-01

    Over the last two decades, functional magnetic resonance imaging (fMRI) has become a powerful research method to investigate cortical visual plasticity. Abnormal fMRI response patterns have been occasionally detected in the visually deprived cortex of patients with bilateral retinal diseases. Controversy remains whether these observations indicate structural reorganization of the visual cortex or unmasking of previously silent cortico-cortical connections. In optic nerve diseases, there is weak evidence showing that early visual cortex seems to lack reorganization, while higher-order visual areas undergo plastic changes which may contribute to optimise visual function. There is however accumulating imaging evidence demonstrating trans-synaptic degeneration of the visual cortex in patients with disease of the anterior visual pathways. This may preclude the use of restorative treatments in these patients. Here, we review and update the body of fMRI evidence on visual cortical plasticity.

  4. 76 FR 71919 - Corporate Reorganizations; Allocation of Basis in “All Cash D” Reorganizations

    Science.gov (United States)

    2011-11-21

    ... Internal Revenue Service 26 CFR Part 1 RIN 1545-BJ21 Corporate Reorganizations; Allocation of Basis in.... Fuller, Office of Associate Chief Counsel (Corporate). However, other personnel from the IRS and the..., Reporting and recordkeeping requirements. Proposed Amendments to the Regulations Accordingly, 26 CFR part...

  5. Functional reorganization of motor and limbic circuits after exercise training in a rat model of bilateral parkinsonism.

    Directory of Open Access Journals (Sweden)

    Zhuo Wang

    Full Text Available Exercise training is widely used for neurorehabilitation of Parkinson's disease (PD. However, little is known about the functional reorganization of the injured brain after long-term aerobic exercise. We examined the effects of 4 weeks of forced running wheel exercise in a rat model of dopaminergic deafferentation (bilateral, dorsal striatal 6-hydroxydopamine lesions. One week after training, cerebral perfusion was mapped during treadmill walking or at rest using [(14C]-iodoantipyrine autoradiography. Regional cerebral blood flow-related tissue radioactivity (rCBF was analyzed in three-dimensionally reconstructed brains by statistical parametric mapping. In non-exercised rats, lesions resulted in persistent motor deficits. Compared to sham-lesioned rats, lesioned rats showed altered functional brain activation during walking, including: 1. hypoactivation of the striatum and motor cortex; 2. hyperactivation of non-lesioned areas in the basal ganglia-thalamocortical circuit; 3. functional recruitment of the red nucleus, superior colliculus and somatosensory cortex; 4. hyperactivation of the ventrolateral thalamus, cerebellar vermis and deep nuclei, suggesting recruitment of the cerebellar-thalamocortical circuit; 5. hyperactivation of limbic areas (amygdala, hippocampus, ventral striatum, septum, raphe, insula. These findings show remarkable similarities to imaging findings reported in PD patients. Exercise progressively improved motor deficits in lesioned rats, while increasing activation in dorsal striatum and rostral secondary motor cortex, attenuating a hyperemia of the zona incerta and eliciting a functional reorganization of regions participating in the cerebellar-thalamocortical circuit. Both lesions and exercise increased activation in mesolimbic areas (amygdala, hippocampus, ventral striatum, laterodorsal tegmental n., ventral pallidum, as well as in related paralimbic regions (septum, raphe, insula. Exercise, but not lesioning, resulted

  6. Structural damage and functional reorganization in ipsilesional m1 in well-recovered patients with subcortical stroke.

    Science.gov (United States)

    Zhang, Jing; Meng, Liangliang; Qin, Wen; Liu, Ningning; Shi, Fu-Dong; Yu, Chunshui

    2014-03-01

    Both structural atrophy and functional reorganization of the primary motor cortex (M1) have been reported in patients with subcortical infarctions affecting the motor pathway. However, the relationship between structural impairment and functional reorganization in M1 remains unclear. Twenty-six patients exhibiting significant recovery after subcortical infarctions were investigated using multimodal MRI techniques. Structural impairment was assessed via cortical thickness, and functional reorganization was analyzed using task-evoked activation, amplitude of low-frequency fluctuation, and resting-state functional connectivity. Compared with healthy controls, patients with stroke exhibited reduced cortical thickness in the ipsilesional M1; however, this region exhibited increased task-evoked activation, amplitude of low-frequency fluctuation, and resting-state functional connectivity in these patients. Patients with stroke demonstrated increased task-evoked activation in another ipsilesional M1 region, in which increased amplitude of low-frequency fluctuation and resting-state functional connectivity were observed. The structural and functional changes in M1 were located selectively in the ipsilesional hemisphere. We provide convincing evidence that indicates extensive functional reorganization in the ipsilesional M1 of patients with chronic subcortical infarctions, including the structurally impaired M1 region.

  7. 16 CFR 802.10 - Stock dividends and splits; reorganizations.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Stock dividends and splits; reorganizations... INTERPRETATIONS UNDER THE HART-SCOTT-RODINO ANTITRUST IMPROVEMENTS ACT OF 1976 EXEMPTION RULES § 802.10 Stock dividends and splits; reorganizations. (a) The acquisition of voting securities pursuant to a stock split...

  8. Rotational reorganization of doped cholesteric liquid crystalline films

    NARCIS (Netherlands)

    Eelkema, R.; M. Pollard, M.; Katsonis, N.; Vicario, J.; J. Broer, D.; Feringa, B.L.

    2006-01-01

    In this paper an unprecedented rotational reorganization of cholesteric liquid crystalline films is described. This rotational reorganization results from the conversion of a chiral molecular motor dopant to an isomer with a different helical twisting power, leading to a change in the cholesteric pi

  9. Perilesional reorganization of motor function in stroke patients

    Institute of Scientific and Technical Information of China (English)

    Sung Ho Jang

    2010-01-01

    Perilesional reorganization is an important recovery mechanism for stroke patients because it yields good motor outcomes. However, perilesional reorganization remains poorly understood. The scientific basis for stroke rehabilitation can be established when detailed mechanisms of recovery are clarified. In addition, studies at the subcortical level remain in the early stages. Therefore, the present study suggested that additional investigations should focus on perilesional reorganization at the subcortical level, identifying the critical period for this mechanism and determining treatment strategies and modalities to facilitate development. The present study reviews literature focused on perilesional reorganization in stroke patients with regard to demonstration, clinical characteristics,and rehabilitative aspects, as well as previous studies of perilesional reorganization at cortical and subcortical levels.

  10. Reorganization of Anatomical Connectome following Electroconvulsive Therapy in Major Depressive Disorder

    Directory of Open Access Journals (Sweden)

    Jinkun Zeng

    2015-01-01

    Full Text Available Objective. Electroconvulsive therapy (ECT is considered one of the most effective and fast-acting treatment options for depressive episodes. Little is known, however, about ECT’s enabling brain (neuroplasticity effects, particular for plasticity of white matter pathway. Materials and Methods. We collected longitudinal diffusion tensor imaging in the first-episode, drug-naïve major depressive disorder (MDD patients n=24 before and after a predefined time window ECT treatment. We constructed large-scale anatomical networks derived from white matter fiber tractography and evaluated the topological reorganization using graph theoretical analysis. We also assessed the relationship between topological reorganization with improvements in depressive symptoms. Results. Our investigation revealed three main findings: (1 the small-worldness was persistent after ECT series; (2 anatomical connections changes were found in limbic structure, temporal and frontal lobes, in which the connection changes between amygdala and parahippocampus correlate with depressive symptom reduction; (3 significant nodal strength changes were found in right paralimbic network. Conclusions. ECT elicits neuroplastic processes associated with improvements in depressive symptoms that act to specific local ventral frontolimbic circuits, but not small-world property. Overall, ECT induced topological reorganization in large-scale brain structural network, opening up new avenues to better understand the mode of ECT action in MDD.

  11. Reorganization of Anatomical Connectome following Electroconvulsive Therapy in Major Depressive Disorder

    Science.gov (United States)

    Zeng, Jinkun; Luo, Qinghua; Du, Lian; Liao, Wei; Li, Yongmei; Liu, Haixia; Liu, Dan; Fu, Yixiao; Qiu, Haitang; Li, Xirong; Qiu, Tian; Meng, Huaqing

    2015-01-01

    Objective. Electroconvulsive therapy (ECT) is considered one of the most effective and fast-acting treatment options for depressive episodes. Little is known, however, about ECT's enabling brain (neuro)plasticity effects, particular for plasticity of white matter pathway. Materials and Methods. We collected longitudinal diffusion tensor imaging in the first-episode, drug-naïve major depressive disorder (MDD) patients (n = 24) before and after a predefined time window ECT treatment. We constructed large-scale anatomical networks derived from white matter fiber tractography and evaluated the topological reorganization using graph theoretical analysis. We also assessed the relationship between topological reorganization with improvements in depressive symptoms. Results. Our investigation revealed three main findings: (1) the small-worldness was persistent after ECT series; (2) anatomical connections changes were found in limbic structure, temporal and frontal lobes, in which the connection changes between amygdala and parahippocampus correlate with depressive symptom reduction; (3) significant nodal strength changes were found in right paralimbic network. Conclusions. ECT elicits neuroplastic processes associated with improvements in depressive symptoms that act to specific local ventral frontolimbic circuits, but not small-world property. Overall, ECT induced topological reorganization in large-scale brain structural network, opening up new avenues to better understand the mode of ECT action in MDD. PMID:26770836

  12. Structural Reorganization of CNC in Injection-Molded CNC/PBAT Materials under Thermal Annealing.

    Science.gov (United States)

    Mariano, Marcos; El Kissi, Nadia; Dufresne, Alain

    2016-10-04

    Composite materials were prepared by extrusion and injection molding from polybutyrate adipate terephthalate (PBAT) and high aspect ratio cellulose nanocrystals (CNCs) extracted from capim dourado fibers. Three CNC contents were used, corresponding to 0.5, 1, and 2 times the theoretical percolation threshold. Small-amplitude oscillary shear (SAOS) experiments show that as the CNC content increases, a more elastic behavior is observed but no percolating network can form within the polymeric matrix as a result of the high shear rates involved during the injection-molding process. Annealing of the samples at 170 °C was performed, and the possible reorganization of the nanofiller was investigated. This reorganization was further elucidated using 2D-SAOS and creep experiments.

  13. Cortical reorganization in patients with subcortical hemiparesis: neural mechanisms of functional recovery and prognostic implication.

    Science.gov (United States)

    Fujii, Yukihiko; Nakada, Tsutomu

    2003-01-01

    A systematic investigation on cortical reorganization in patients with hemiparesis of a subcortical origin, with special emphasis on functional correlates, was conducted using functional magnetic resonance (fMR) imaging performed on a 3-tesla system specifically optimized for fMR imaging investigation. The study group included 46 patients with hemiparesis (25 with right and 21 with left hemiparesis) and 30 age-matched healthy volunteers as controls. All study participants were originally right handed. The characteristics of the lesion were putaminal hemorrhage in 19 patients, thalamic hemorrhage in 10 patients, and striatocapsular bland infarction in 17 patients. Functional recovery in subcortical hemiparesis showed two distinct phases of the recovery process involving entirely different neural mechanisms. Phase I is characterized by the process of recovery and/or reorganization of the primary system. Successful recovery of this system is typically reached within 1 month after stroke onset. Its clinical correlate is a rapid recovery course and significant recovery of function within 1 month of stroke onset. Failure of recovery of the primary system shifts the recovery process to Phase II, during which reorganization involving the ipsilateral pathway takes place. The clinical correlate of Phase II is a slow recovery course with variable functional outcome. Effective functional organization of the ipsilateral pathway, as identified by linked activation of the ipsilateral primary sensorimotor cortex and contralateral anterior lobe of the cerebellum, is correlated with a good prognostic outcome for patients in the slow recovery group. A high degree of connectivity between supplementary motor areas, bilaterally, appears to influence functional recovery adversely.

  14. Human prefrontal cortex: evolution, development, and pathology.

    Science.gov (United States)

    Teffer, Kate; Semendeferi, Katerina

    2012-01-01

    The prefrontal cortex is critical to many cognitive abilities that are considered particularly human, and forms a large part of a neural system crucial for normal socio-emotional and executive functioning in humans and other primates. In this chapter, we survey the literature regarding prefrontal development and pathology in humans as well as comparative studies of the region in humans and closely related primate species. The prefrontal cortex matures later in development than more caudal regions, and some of its neuronal subpopulations exhibit more complex dendritic arborizations. Comparative work suggests that the human prefrontal cortex differs from that of closely related primate species less in relative size than it does in organization. Specific reorganizational events in neural circuitry may have taken place either as a consequence of adjusting to increases in size or as adaptive responses to specific selection pressures. Living in complex environments has been recognized as a considerable factor in the evolution of primate cognition. Normal frontal lobe development and function are also compromised in several neurological and psychiatric disorders. A phylogenetically recent reorganization of frontal cortical circuitry may have been critical to the emergence of human-specific executive and social-emotional functions, and developmental pathology in these same systems underlies many psychiatric and neurological disorders, including autism and schizophrenia.

  15. Aging causes a reorganization of cortical and spinal control of posture

    Directory of Open Access Journals (Sweden)

    Selma ePapegaaij

    2014-03-01

    Full Text Available Classical studies in animal preparations suggest a strong role for spinal control of posture. In young adults it is now established that the cerebral cortex contributes to postural control of unperturbed and perturbed standing. The age-related degeneration and accompanying functional changes in the brain, reported so far mainly in conjunction with simple manual motor tasks, may also affect the mechanisms that control complex motor tasks involving posture. This review outlines the age-related structural and functional changes at spinal and cortical levels and provides a mechanistic analysis of how such changes may be linked to the behaviorally manifest postural deficits in old adults. The emerging picture is that the age-related reorganization in motor control during voluntary tasks, characterized by differential modulation of spinal reflexes, greater cortical activation and cortical disinhibition, is also present during postural tasks. We discuss the possibility that this reorganization underlies the increased coactivation and dual task interference reported in elderly. Finally, we propose a model for future studies to unravel the structure-function-behavior relations in postural control and aging.

  16. Brain reorganization, not relative brain size, primarily characterizes anthropoid brain evolution.

    Science.gov (United States)

    Smaers, J B; Soligo, C

    2013-05-22

    Comparative analyses of primate brain evolution have highlighted changes in size and internal organization as key factors underlying species diversity. It remains, however, unclear (i) how much variation in mosaic brain reorganization versus variation in relative brain size contributes to explaining the structural neural diversity observed across species, (ii) which mosaic changes contribute most to explaining diversity, and (iii) what the temporal origin, rates and processes are that underlie evolutionary shifts in mosaic reorganization for individual branches of the primate tree of life. We address these questions by combining novel comparative methods that allow assessing the temporal origin, rate and process of evolutionary changes on individual branches of the tree of life, with newly available data on volumes of key brain structures (prefrontal cortex, frontal motor areas and cerebrocerebellum) for a sample of 17 species (including humans). We identify patterns of mosaic change in brain evolution that mirror brain systems previously identified by electrophysiological and anatomical tract-tracing studies in non-human primates and functional connectivity MRI studies in humans. Across more than 40 Myr of anthropoid primate evolution, mosaic changes contribute more to explaining neural diversity than changes in relative brain size, and different mosaic patterns are differentially selected for when brains increase or decrease in size. We identify lineage-specific evolutionary specializations for all branches of the tree of life covered by our sample and demonstrate deep evolutionary roots for mosaic patterns associated with motor control and learning.

  17. Cross-modal re-organization in adults with early stage hearing loss.

    Science.gov (United States)

    Campbell, Julia; Sharma, Anu

    2014-01-01

    Cortical cross-modal re-organization, or recruitment of auditory cortical areas for visual processing, has been well-documented in deafness. However, the degree of sensory deprivation necessary to induce such cortical plasticity remains unclear. We recorded visual evoked potentials (VEP) using high-density electroencephalography in nine persons with adult-onset mild-moderate hearing loss and eight normal hearing control subjects. Behavioral auditory performance was quantified using a clinical measure of speech perception-in-noise. Relative to normal hearing controls, adults with hearing loss showed significantly larger P1, N1, and P2 VEP amplitudes, decreased N1 latency, and a novel positive component (P2') following the P2 VEP. Current source density reconstruction of VEPs revealed a shift toward ventral stream processing including activation of auditory temporal cortex in hearing-impaired adults. The hearing loss group showed worse than normal speech perception performance in noise, which was strongly correlated with a decrease in the N1 VEP latency. Overall, our findings provide the first evidence that visual cross-modal re-organization not only begins in the early stages of hearing impairment, but may also be an important factor in determining behavioral outcomes for listeners with hearing loss, a finding which demands further investigation.

  18. Corticospinal Reorganization after Locomotor Training in a Person with Motor Incomplete Paraplegia

    Directory of Open Access Journals (Sweden)

    Nupur Hajela

    2013-01-01

    Full Text Available Activity-dependent plasticity as a result of reorganization of neural circuits is a fundamental characteristic of the central nervous system that occurs simultaneously in multiple sites. In this study, we established the effects of subthreshold transcranial magnetic stimulation (TMS over the primary motor cortex region on the tibialis anterior (TA long-latency flexion reflex. Neurophysiological tests were conducted before and after robotic gait training in one person with a motor incomplete spinal cord injury (SCI while at rest and during robotic-assisted stepping. The TA flexion reflex was evoked following nonnociceptive sural nerve stimulation and was conditioned by TMS at 0.9 TA motor evoked potential resting threshold at conditioning-test intervals that ranged from 70 to 130 ms. Subthreshold TMS induced a significant facilitation on the TA flexion reflex before training, which was reversed to depression after training with the subject seated at rest. During stepping, corticospinal facilitation of the flexion reflex at early and midstance phases before training was replaced with depression at early and midswing followed by facilitation at late swing after training. These results constitute the first neurophysiologic evidence that locomotor training reorganizes the cortical control of spinal interneuronal circuits that generate patterned motor activity, modifying spinal reflex function, in the chronic lesioned human spinal cord.

  19. Reading acquisition reorganizes the phonological awareness network only in alphabetic writing systems.

    Science.gov (United States)

    Brennan, Christine; Cao, Fan; Pedroarena-Leal, Nicole; McNorgan, Chris; Booth, James R

    2013-12-01

    It is unknown how experience with different types of orthographies influences the neural basis of oral language processing. In order to determine the effects of alphabetic and nonalphabetic writing systems, the current study examined the influence of learning to read on oral language in English and Chinese speakers. Children (8-12 years olds) and adults made rhyming judgments to pairs of spoken words during functional magnetic resonance imaging (fMRI). Developmental increases were seen only for English speakers in the left hemisphere phonological network (superior temporal gyrus (STG), inferior parietal lobule, and inferior frontal gyrus). The increase in the STG was more pronounced for words with conflicting orthography (e.g. pint-mint; jazz-has) even though access to orthography was irrelevant to the task. Moreover, higher reading skill was correlated with greater activation in the STG only for English speaking children. The effects suggest that learning to read reorganizes the phonological awareness network only for alphabetic and not logographic writing systems because of differences in the principles for mapping between orthographic and phonological representations. The reorganization of the auditory cortex may result in better phonological awareness skills in alphabetic readers. Copyright © 2012 Wiley Periodicals, Inc.

  20. Cross-modal re-organization in adults with early stage hearing loss.

    Directory of Open Access Journals (Sweden)

    Julia Campbell

    Full Text Available Cortical cross-modal re-organization, or recruitment of auditory cortical areas for visual processing, has been well-documented in deafness. However, the degree of sensory deprivation necessary to induce such cortical plasticity remains unclear. We recorded visual evoked potentials (VEP using high-density electroencephalography in nine persons with adult-onset mild-moderate hearing loss and eight normal hearing control subjects. Behavioral auditory performance was quantified using a clinical measure of speech perception-in-noise. Relative to normal hearing controls, adults with hearing loss showed significantly larger P1, N1, and P2 VEP amplitudes, decreased N1 latency, and a novel positive component (P2' following the P2 VEP. Current source density reconstruction of VEPs revealed a shift toward ventral stream processing including activation of auditory temporal cortex in hearing-impaired adults. The hearing loss group showed worse than normal speech perception performance in noise, which was strongly correlated with a decrease in the N1 VEP latency. Overall, our findings provide the first evidence that visual cross-modal re-organization not only begins in the early stages of hearing impairment, but may also be an important factor in determining behavioral outcomes for listeners with hearing loss, a finding which demands further investigation.

  1. Medial reorganization of motor function in corona radiata following middle cerebral artery infarction A case report

    Institute of Scientific and Technical Information of China (English)

    Sung Ho Jang

    2009-01-01

    Peri-lesional reorganization is one of the motor recovery mechanisms following stroke. A 23-year-old female who presented with complete paralysis of the right extremities at the onset of infarct in the left middle cerebral artery territory was included. She slowly recovered some function, and could extend the affected knee with resistance after 9 months. Diffusion tensor tractography, functional MRI, and transcranial magnetic stimulation testing were performed at 7 years after onset. Results showed that diffusion tensor tractography of the affected (left) hemisphere passed through the medial corona radiata at, or around, the wall of the lateral ventricle. The contralateral primary sensorimotor cortex was activated during affected knee movements. The motor-evoked potential, which was obtained from the affected leg, exhibited corticospinal tract characteristics. Results indicated that motor function of the affected leg recovered via the corticospinal tract, which descended through the corona radiata medial to the infarct. The motor function of the affected leg was reorganized to the medial corona radiata following infarct to the middle cerebral artery territory.

  2. From oocyte to 16-cell stage: cytoplasmic and cortical reorganizations that pattern the ascidian embryo.

    Science.gov (United States)

    Sardet, Christian; Paix, Alexandre; Prodon, François; Dru, Philippe; Chenevert, Janet

    2007-07-01

    a macroscopic cortical structure called the Centrosome Attracting Body (CAB). The CAB is responsible for a series of unequal divisions in posterior-vegetal blastomeres, and the postplasmic/PEM RNAs it contains are involved in patterning the posterior region of the embryo. In this review, we discuss these multiple events and phases of reorganizations in detail and their relationship to physiological, cell cycle, and cytoskeletal events. We also examine the role of the reorganizations in localizing determinants, postplasmic/PEM RNAs, and PAR polarity proteins in the cortex. Finally, we summarize some of the remaining questions concerning polarization of the ascidian embryo and provide comparisons to a few other species. A large collection of films illustrating the reorganizations can be consulted by clicking on "Film archive: ascidian eggs and embryos" at http://biodev.obs-vlfr.fr/recherche/biomarcell/.

  3. Reassessing cortical reorganization in the primary sensorimotor cortex following arm amputation

    OpenAIRE

    Makin, Tamar R.; Scholz, Jan; Henderson Slater, David; Johansen-Berg, Heidi; Tracey, Irene

    2015-01-01

    The role of cortical activity in generating and abolishing chronic pain is increasingly emphasized in the clinical community. Perhaps the most striking example of this is the maladaptive plasticity theory, according to which phantom pain arises from remapping of cortically neighbouring representations (lower face) into the territory of the missing hand following amputation. This theory has been extended to a wide range of chronic pain conditions, such as complex regional pain syndrome. Yet, d...

  4. Cortical reorganization after long-term adaptation to retinal lesions in humans.

    Science.gov (United States)

    Chung, Susana T L

    2013-11-13

    Single-unit recordings demonstrated that the adult mammalian visual cortex is capable of reorganizing after induced retinal lesions. In humans, whether the adult cortex is capable of reorganizing has only been studied using functional magnetic resonance imaging, with equivocal results. Here, we exploited the phenomenon of visual crowding, a major limitation on object recognition, to show that, in humans with long-standing retinal (macular) lesions that afflict the fovea and thus use their peripheral vision exclusively, the signature properties of crowding are distinctly different from those of the normal periphery. Crowding refers to the inability to recognize objects when the object spacing is smaller than the critical spacing. Critical spacing depends only on the retinal location of the object, scales linearly with its distance from the fovea, and is approximately two times larger in the radial than the tangential direction with respect to the fovea, thus demonstrating the signature radial-tangential anisotropy of the crowding zone. Using retinal imaging combined with behavioral measurements, we mapped out the crowding zone at the precise peripheral retinal locations adopted by individuals with macular lesions as the new visual reference loci. At these loci, the critical spacings are substantially smaller along the radial direction than expected based on the normal periphery, resulting in a lower scaling of critical spacing with the eccentricity of the peripheral locus and a loss in the signature radial-tangential anisotropy of the crowding zone. These results imply a fundamental difference in the substrate of cortical processing in object recognition following long-term adaptation to macular lesions.

  5. Drawing in the blind and the sighted as a probe of cortical reorganization

    Science.gov (United States)

    Likova, Lora T.

    2010-02-01

    In contrast to other arts, such as music, there is a very little neuroimaging research on visual art and in particular - on drawing. Drawing - from artistic to technical - involves diverse aspects of spatial cognition, precise sensorimotor planning and control as well as a rich set of higher cognitive functions. A new method for learning the drawing skill in the blind that we have developed, and the technological advances of a multisensory MR-compatible drawing system, allowed us to run for the first time a comparative fMRI study on drawing in the blind and the sighted. In each population, we identified widely distributed cortical networks, extending from the occipital and temporal cortices, through the parietal to the frontal lobe. This is the first neuroimaging study of drawing in blind novices, as well as the first study on the learning to draw in either population. We sought to determine the cortical reorganization taking place as a result of learning to draw, despite the lack of visual input to the brains of the blind. Remarkably, we found massive recruitment of the visual cortex on learning to draw, although our subjects had no previous experience, but only a short training with our new drawing method. This finding implies a rapid, learning-based plasticity mechanism. We further proposed that the functional level of the brain reorganization in the blind may still differ from that in the sighted even in areas that overlap between the two populations, such as in the visual cortex. We tested this idea in the framework of saccadic suppression. A methodological innovation allowed us to estimate the retinotopic regions locations in the blind brain. Although the visual cortex of both groups was greatly recruited, only the sighted experienced dramatic suppression in hMT+ and V1, while there was no sign of an analogous process in the blind. This finding has important implications and suggests that the recruitment of the visual cortex in the blind does not assure a

  6. 75 FR 29451 - Agency Reorganization and Delegations of Authority

    Science.gov (United States)

    2010-05-26

    ... January 31, 2010, and to delegate authority to certain FMC bureaus and offices in order to improve the FMC... No. 10-04] RIN 3072-AC37 Agency Reorganization and Delegations of Authority AGENCY: Federal Maritime...

  7. Prolonged reorganization of thiol-capped Au nanoparticles layered structures

    Directory of Open Access Journals (Sweden)

    Sarathi Kundu

    2013-09-01

    Full Text Available Prolonged reorganization behaviour of mono-, di-, tri- and multi-layer films of Au nanoparticles prepared by Langmuir-Blodgett method on hydrophobic Si(001 substrates have been studied by using X-ray scattering techniques. Out-of-plane study shows that although at the initial stage the reorganization occurs through the compaction of the films keeping the layered structure unchanged but finally all layered structures modify to monolayer structure. Due to this reorganization the Au density increases within the nanometer thick films. In-plane study shows that inside the reorganized films Au nanoparticles are distributed randomly and the particle size modifies as the metallic core of Au nanoparticles coalesces.

  8. Tinnitus intensity dependent gamma oscillations of the contralateral auditory cortex.

    Directory of Open Access Journals (Sweden)

    Elsa van der Loo

    Full Text Available BACKGROUND: Non-pulsatile tinnitus is considered a subjective auditory phantom phenomenon present in 10 to 15% of the population. Tinnitus as a phantom phenomenon is related to hyperactivity and reorganization of the auditory cortex. Magnetoencephalography studies demonstrate a correlation between gamma band activity in the contralateral auditory cortex and the presence of tinnitus. The present study aims to investigate the relation between objective gamma-band activity in the contralateral auditory cortex and subjective tinnitus loudness scores. METHODS AND FINDINGS: In unilateral tinnitus patients (N = 15; 10 right, 5 left source analysis of resting state electroencephalographic gamma band oscillations shows a strong positive correlation with Visual Analogue Scale loudness scores in the contralateral auditory cortex (max r = 0.73, p<0.05. CONCLUSION: Auditory phantom percepts thus show similar sound level dependent activation of the contralateral auditory cortex as observed in normal audition. In view of recent consciousness models and tinnitus network models these results suggest tinnitus loudness is coded by gamma band activity in the contralateral auditory cortex but might not, by itself, be responsible for tinnitus perception.

  9. Functional Reorganizations of Brain Network in Prelingually Deaf Adolescents

    OpenAIRE

    Wenjing Li; Jianhong Li; Jieqiong Wang; Peng Zhou; Zhenchang Wang; Junfang Xian; Huiguang He

    2016-01-01

    Previous neuroimaging studies suggested structural or functional brain reorganizations occurred in prelingually deaf subjects. However, little is known about the reorganizations of brain network architectures in prelingually deaf adolescents. The present study aims to investigate alterations of whole-brain functional network using resting-state fMRI and graph theory analysis. We recruited 16 prelingually deaf adolescents (10~18 years) and 16 normal controls matched in age and gender. Brain ne...

  10. ERK is involved in the reorganization of somatosensory cortical maps in adult rats submitted to hindlimb unloading.

    Directory of Open Access Journals (Sweden)

    Erwan Dupont

    Full Text Available Sensorimotor restriction by a 14-day period of hindlimb unloading (HU in the adult rat induces a reorganization of topographic maps and receptive fields. However, the underlying mechanisms are still unclear. Interest was turned towards a possible implication of intracellular MAPK signaling pathway since Extracellular-signal-Regulated Kinase 1/2 (ERK1/2 is known to play a significant role in the control of synaptic plasticity. In order to better understand the mechanisms underlying cortical plasticity in adult rats submitted to a sensorimotor restriction, we analyzed the time-course of ERK1/2 activation by immunoblot and of cortical reorganization by electrophysiological recordings, on rats submitted to hindlimb unloading over four weeks. Immunohistochemistry analysis provided evidence that ERK1/2 phosphorylation was increased in layer III neurons of the somatosensory cortex. This increase was transient, and parallel to the changes in hindpaw cortical map area (layer IV. By contrast, receptive fields were progressively enlarged from 7 to 28 days of hindlimb unloading. To determine whether ERK1/2 was involved in cortical remapping, we administered a specific ERK1/2 inhibitor (PD-98059 through osmotic mini-pump in rats hindlimb unloaded for 14 days. Results demonstrate that focal inhibition of ERK1/2 pathway prevents cortical reorganization, but had no effect on receptive fields. These results suggest that ERK1/2 plays a role in the induction of cortical plasticity during hindlimb unloading.

  11. Contralesional cortical structural reorganization contributes to motor recovery after sub-cortical stroke: A longitudinal voxel-based morphometry study

    Directory of Open Access Journals (Sweden)

    Jianxin Cai

    2016-08-01

    Full Text Available Although changes in brain gray matter after stroke have been identified in some neuroimaging studies, lesion heterogeneity and individual variability make the detection of potential neuronal reorganization difficult. This study attempted to investigate the potential structural cortical reorganization after sub-cortical stroke using a longitudinal voxel-based gray matter volume (GMV analysis. Eleven right-handed patients with first -onset, subcortical, ischemic infarctions involving the basal ganglia regions underwent structural magnetic resonance imaging in addition to National Institutes of Health Stroke Scale and Motricity Index assessments in the acute (< 5 days and chronic stages (1 year later. The GMVs were calculated and compared between the two stages using nonparametric permutation paired t tests. Moreover, the Spearman correlations between the GMV changes and clinical recoveries were analyzed. Compared with the acute stage, significant decreases in GMV were observed in the ipsilesional precentral gyrus (PreCG, paracentral gyrus, and contralesional cerebellar lobule VII in the chronic stage. Additionally, significant increases in GMV were found in the contralesional orbitofrontal cortex (OFC and middle (MFG and inferior (IFG frontal gyri. Furthermore, severe GMV atrophy in the ipsilesional PreCG predicted poorer clinical recovery, and greater GMV increases in the contralesional OFG and MFG predicted better clinical recovery. Our findings suggest that structural reorganization of the contralesional ‘cognitive’ cortices might contribute to motor recovery after sub-cortical stroke.

  12. A simple rule for dendritic spine and axonal bouton formation can account for cortical reorganization after focal retinal lesions.

    Directory of Open Access Journals (Sweden)

    Markus Butz

    Full Text Available Lasting alterations in sensory input trigger massive structural and functional adaptations in cortical networks. The principles governing these experience-dependent changes are, however, poorly understood. Here, we examine whether a simple rule based on the neurons' need for homeostasis in electrical activity may serve as driving force for cortical reorganization. According to this rule, a neuron creates new spines and boutons when its level of electrical activity is below a homeostatic set-point and decreases the number of spines and boutons when its activity exceeds this set-point. In addition, neurons need a minimum level of activity to form spines and boutons. Spine and bouton formation depends solely on the neuron's own activity level, and synapses are formed by merging spines and boutons independently of activity. Using a novel computational model, we show that this simple growth rule produces neuron and network changes as observed in the visual cortex after focal retinal lesions. In the model, as in the cortex, the turnover of dendritic spines was increased strongest in the center of the lesion projection zone, while axonal boutons displayed a marked overshoot followed by pruning. Moreover, the decrease in external input was compensated for by the formation of new horizontal connections, which caused a retinotopic remapping. Homeostatic regulation may provide a unifying framework for understanding cortical reorganization, including network repair in degenerative diseases or following focal stroke.

  13. Imaging studies in congenital anophthalmia reveal preservation of brain architecture in 'visual' cortex.

    Science.gov (United States)

    Bridge, Holly; Cowey, Alan; Ragge, Nicola; Watkins, Kate

    2009-12-01

    The functional specialization of the human brain means that many regions are dedicated to processing a single sensory modality. When a modality is absent, as in congenital total blindness, 'visual' regions can be reliably activated by non-visual stimuli. The connections underlying this functional adaptation, however, remain elusive. In this study, using structural and diffusion-weighted magnetic resonance imaging, we investigated the structural differences in the brains of six bilaterally anophthalmic subjects compared with sighted subjects. Surprisingly, the gross structural differences in the brains were small, even in the occipital lobe where only a small region of the primary visual cortex showed a bilateral reduction in grey matter volume in the anophthalmic subjects compared with controls. Regions of increased cortical thickness were apparent on the banks of the Calcarine sulcus, but not in the fundus. Subcortically, the white matter volume around the optic tract and internal capsule in anophthalmic subjects showed a large decrease, yet the optic radiation volume did not differ significantly. However, the white matter integrity, as measured with fractional anisotropy showed an extensive reduction throughout the brain in the anophthalmic subjects, with the greatest difference in the optic radiations. In apparent contradiction to the latter finding, the connectivity between the lateral geniculate nucleus and primary visual cortex measured with diffusion tractography did not differ between the two populations. However, these findings can be reconciled by a demonstration that at least some of the reduction in fractional anisotropy in the optic radiation is due to an increase in the strength of fibres crossing the radiations. In summary, the major changes in the 'visual' brain in anophthalmic subjects may be subcortical, although the evidence of decreased fractional anisotropy and increased crossing fibres could indicate considerable re-organization.

  14. Neonatal Neurobehavior and Diffusion MRI Changes in Brain Reorganization Due to Intrauterine Growth Restriction in a Rabbit Model

    Science.gov (United States)

    Eixarch, Elisenda; Batalle, Dafnis; Illa, Miriam; Muñoz-Moreno, Emma; Arbat-Plana, Ariadna; Amat-Roldan, Ivan; Figueras, Francesc; Gratacos, Eduard

    2012-01-01

    Background Intrauterine growth restriction (IUGR) affects 5–10% of all newborns and is associated with a high risk of abnormal neurodevelopment. The timing and patterns of brain reorganization underlying IUGR are poorly documented. We developed a rabbit model of IUGR allowing neonatal neurobehavioral assessment and high resolution brain diffusion magnetic resonance imaging (MRI). The aim of the study was to describe the pattern and functional correlates of fetal brain reorganization induced by IUGR. Methodology/Principal Findings IUGR was induced in 10 New Zealand fetal rabbits by ligation of 40–50% of uteroplacental vessels in one horn at 25 days of gestation. Ten contralateral horn fetuses were used as controls. Cesarean section was performed at 30 days (term 31 days). At postnatal day +1, neonates were assessed by validated neurobehavioral tests including evaluation of tone, spontaneous locomotion, reflex motor activity, motor responses to olfactory stimuli, and coordination of suck and swallow. Subsequently, brains were collected and fixed and MRI was performed using a high resolution acquisition scheme. Global and regional (manual delineation and voxel based analysis) diffusion tensor imaging parameters were analyzed. IUGR was associated with significantly poorer neurobehavioral performance in most domains. Voxel based analysis revealed fractional anisotropy (FA) differences in multiple brain regions of gray and white matter, including frontal, insular, occipital and temporal cortex, hippocampus, putamen, thalamus, claustrum, medial septal nucleus, anterior commissure, internal capsule, fimbria of hippocampus, medial lemniscus and olfactory tract. Regional FA changes were correlated with poorer outcome in neurobehavioral tests. Conclusions IUGR is associated with a complex pattern of brain reorganization already at birth, which may open opportunities for early intervention. Diffusion MRI can offer suitable imaging biomarkers to characterize and monitor

  15. Shaping Early Reorganization of Neural Networks Promotes Motor Function after Stroke.

    Science.gov (United States)

    Volz, L J; Rehme, A K; Michely, J; Nettekoven, C; Eickhoff, S B; Fink, G R; Grefkes, C

    2016-06-01

    Neural plasticity is a major factor driving cortical reorganization after stroke. We here tested whether repetitively enhancing motor cortex plasticity by means of intermittent theta-burst stimulation (iTBS) prior to physiotherapy might promote recovery of function early after stroke. Functional magnetic resonance imaging (fMRI) was used to elucidate underlying neural mechanisms. Twenty-six hospitalized, first-ever stroke patients (time since stroke: 1-16 days) with hand motor deficits were enrolled in a sham-controlled design and pseudo-randomized into 2 groups. iTBS was administered prior to physiotherapy on 5 consecutive days either over ipsilesional primary motor cortex (M1-stimulation group) or parieto-occipital vertex (control-stimulation group). Hand motor function, cortical excitability, and resting-state fMRI were assessed 1 day prior to the first stimulation and 1 day after the last stimulation. Recovery of grip strength was significantly stronger in the M1-stimulation compared to the control-stimulation group. Higher levels of motor network connectivity were associated with better motor outcome. Consistently, control-stimulated patients featured a decrease in intra- and interhemispheric connectivity of the motor network, which was absent in the M1-stimulation group. Hence, adding iTBS to prime physiotherapy in recovering stroke patients seems to interfere with motor network degradation, possibly reflecting alleviation of post-stroke diaschisis.

  16. Reorganization of brain function after a short-term behavioral intervention for stuttering.

    Science.gov (United States)

    Lu, Chunming; Zheng, Lifen; Long, Yuhang; Yan, Qian; Ding, Guosheng; Liu, Li; Peng, Danling; Howell, Peter

    2017-05-01

    This study investigated changes in brain function that occurred over a 7-day behavioral intervention for adults who stutter (AWS). Thirteen AWS received the intervention (AWS+), and 13 AWS did not receive the intervention (AWS-). There were 13 fluent controls (FC-). All participants were scanned before and after the intervention. Whole-brain analysis pre-intervention showed significant differences in task-related brain activation between AWS and FC- in the right inferior frontal cortex (IFC) and left middle temporal cortex, but there were no differences between the two AWS groups. Across the 7-day period of the intervention, AWS+ alone showed a significant increase of brain activation in the left ventral IFC/insula. There were no changes in brain function for the other two groups. Further analysis revealed that the change did not correlate with resting-state functional connectivity (RSFC) that AWS showed in the cerebellum (Lu et al., 2012). However, both changes in task-related brain function and RSFC correlated with changes in speech fluency level. Together, these findings suggest that functional reorganization in a brain region close to the left IFC that shows anomalous function in AWS, occurs after a short-term behavioral intervention for stuttering. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Cerebral Reorganization in Subacute Stroke Survivors after Virtual Reality-Based Training: A Preliminary Study

    Directory of Open Access Journals (Sweden)

    Xiang Xiao

    2017-01-01

    Full Text Available Background. Functional magnetic resonance imaging (fMRI is a promising method for quantifying brain recovery and investigating the intervention-induced changes in corticomotor excitability after stroke. This study aimed to evaluate cortical reorganization subsequent to virtual reality-enhanced treadmill (VRET training in subacute stroke survivors. Methods. Eight participants with ischemic stroke underwent VRET for 5 sections per week and for 3 weeks. fMRI was conducted to quantify the activity of selected brain regions when the subject performed ankle dorsiflexion. Gait speed and clinical scales were also measured before and after intervention. Results. Increased activation in the primary sensorimotor cortex of the lesioned hemisphere and supplementary motor areas of both sides for the paretic foot (p<0.01 was observed postintervention. Statistically significant improvements were observed in gait velocity (p<0.05. The change in voxel counts in the primary sensorimotor cortex of the lesioned hemisphere is significantly correlated with improvement of 10 m walk time after VRET (r=−0.719. Conclusions. We observed improved walking and increased activation in cortical regions of stroke survivors after VRET training. Moreover, the cortical recruitment was associated with better walking function. Our study suggests that cortical networks could be a site of plasticity, and their recruitment may be one mechanism of training-induced recovery of gait function in stroke. This trial is registered with ChiCTR-IOC-15006064.

  18. Prediction of reorganization free energies for biological electron transfer: a comparative study of Ru-modified cytochromes and a 4-helix bundle protein.

    Science.gov (United States)

    Tipmanee, Varomyalin; Oberhofer, Harald; Park, Mina; Kim, Kwang S; Blumberger, Jochen

    2010-12-01

    The acceleration of electron transfer (ET) rates in redox proteins relative to aqueous solutes can be attributed to the protein's ability to reduce the nuclear response or reorganization upon ET, while maintaining sufficiently high electronic coupling. Quantitative predictions of reorganization free energy remain a challenge, both experimentally and computationally. Using density functional calculations and molecular dynamics simulation with an electronically polarizable force field, we report reorganization free energies for intraprotein ET in four heme-containing ET proteins that differ in their protein fold, hydrophilicity, and solvent accessibility of the electron-accepting group. The reorganization free energies for ET from the heme cofactors of cytochrome c and b(5) to solvent exposed Ru-complexes docked to histidine residues at the surface of these proteins fall within a narrow range of 1.2-1.3 eV. Reorganization free energy is significantly lowered in a designed 4-helix bundle protein where both redox active cofactors are protected from the solvent. For all ET reactions investigated, the major components of reorganization are the solvent and the protein, with the solvent contributing close to or more than 50% of the total. In three out of four proteins, the protein reorganization free energy can be viewed as a collective effect including many residues, each of which contributing a small fraction. These results have important implications for the design of artificial electron transport proteins. They suggest that reorganization free energy may in general not be effectively controlled by single point mutations, but to a large extent by the degree of solvent exposure of the ionizable cofactors.

  19. School District Reorganization: A Qualified Success.

    Science.gov (United States)

    Canter, Gary

    The circumstances preceding and following the 1984 merger of two small school districts in North Central New York State contained cooperation, controversy, and disharmony. The school districts had enough similarities--in their rural, agricultural base, in the pride and loyalty with which many residents viewed their schools, in the central role…

  20. Structural and functional reorganization of propriospinal connections promotes functional recovery after spinal cord injury

    Institute of Scientific and Technical Information of China (English)

    Linard Filli; Martin E Schwab

    2015-01-01

    Axonal regeneration and ifber regrowth is limited in the adult central nervous system, but re-search over the last decades has revealed a high intrinsic capacity of brain and spinal cord circuits to adapt and reorganize after smaller injuries or denervation. Short-distance ifber growth and synaptic rewiring was found in cortex, brain stem and spinal cord and could be associated with restoration of sensorimotor functions that were impaired by the injury. Such processes of struc-tural plasticity were initially observed in the corticospinal system following spinal cord injury or stroke, but recent studies showed an equally high potential for structural and functional reorganization in reticulospinal, rubrospinal or propriospinal projections. Here we review the lesion-induced plastic changes in the propriospinal pathways, and we argue that they represent a key mechanism triggering sensorimotor recovery upon incomplete spinal cord injury. The for-mation or strengthening of spinal detour pathways bypassing supraspinal commands around the lesion site to the denervated spinal cord were identiifed as prominent neural substrate inducing substantial motor recovery in different species from mice to primates. Indications for the exis-tence of propriospinal bypasses were also found in humans after cortical stroke. It is mandatory for current research to dissect the biological mechanisms underlying spinal circuit remodeling and to investigate how these processes can be stimulated in an optimal way by therapeutic inter-ventions (e.g., ifber-growth enhancing interventions, rehabilitation). This knowledge will clear the way for the development of novel strategies targeting the remarkable plastic potential of pro-priospinal circuits to maximize functional recovery after spinal cord injury.

  1. Reorganization of neuronal circuits of the central olfactory system during postprandial sleep.

    Science.gov (United States)

    Yamaguchi, Masahiro; Manabe, Hiroyuki; Murata, Koshi; Mori, Kensaku

    2013-01-01

    Plastic changes in neuronal circuits often occur in association with specific behavioral states. In this review, we focus on an emerging view that neuronal circuits in the olfactory system are reorganized along the wake-sleep cycle. Olfaction is crucial to sustaining the animals' life, and odor-guided behaviors have to be newly acquired or updated to successfully cope with a changing odor world. It is therefore likely that neuronal circuits in the olfactory system are highly plastic and undergo repeated reorganization in daily life. A remarkably plastic feature of the olfactory system is that newly generated neurons are continually integrated into neuronal circuits of the olfactory bulb (OB) throughout life. New neurons in the OB undergo an extensive selection process, during which many are eliminated by apoptosis for the fine tuning of neuronal circuits. The life and death decision of new neurons occurs extensively during a short time window of sleep after food consumption (postprandial sleep), a typical daily olfactory behavior. We review recent studies that explain how olfactory information is transferred between the OB and the olfactory cortex (OC) along the course of the wake-sleep cycle. Olfactory sensory input is effectively transferred from the OB to the OC during waking, while synchronized top-down inputs from the OC to the OB are promoted during the slow-wave sleep. We discuss possible neuronal circuit mechanisms for the selection of new neurons in the OB, which involves the encoding of olfactory sensory inputs and memory trace formation during waking and internally generated activities in the OC and OB during subsequent sleep. The plastic changes in the OB and OC are well coordinated along the course of olfactory behavior during wakefulness and postbehavioral rest and sleep. We therefore propose that the olfactory system provides an excellent model in which to understand behavioral state-dependent plastic mechanisms of the neuronal circuits in the brain.

  2. Reorganization of neuronal circuits of the central olfactory system during postprandial sleep

    Directory of Open Access Journals (Sweden)

    Masahiro eYamaguchi

    2013-08-01

    Full Text Available Plastic changes in neuronal circuits often occur in association with specific behavioral states. In this review, we focus on an emerging view that neuronal circuits in the olfactory system are reorganized along the wake-sleep cycle. Olfaction is crucial to sustaining the animals’ life, and odor-guided behaviors have to be newly acquired or updated to successfully cope with a changing odor world. It is therefore likely that neuronal circuits in the olfactory system are highly plastic and undergo repeated reorganization in daily life. A remarkably plastic feature of the olfactory system is that newly generated neurons are continually integrated into neuronal circuits of the olfactory bulb (OB throughout life. New neurons in the OB undergo an extensive selection process, during which many are eliminated by apoptosis for the fine tuning of neuronal circuits. The life and death decision of new neurons occurs extensively during a short time window of sleep after food consumption (postprandial sleep, a typical daily olfactory behavior. We review recent studies that explain how olfactory information is transferred between the OB and the olfactory cortex (OC along the course of the wake-sleep cycle. Olfactory sensory input is effectively transferred from the OB to the OC during waking, while synchronized top-down inputs from the OC to the OB are promoted during the slow-wave sleep. We discuss possible neuronal circuit mechanisms for the selection of new neurons in the OB, which involves the encoding of olfactory sensory inputs and memory trace formation during waking and internally generated activities in the OC and OB during subsequent sleep. The plastic changes in the OB and OC are well coordinated along the course of olfactory behavior during wakefulness and postbehavioral rest and sleep. We therefore propose that the olfactory system provides an excellent model in which to understand behavioral state-dependent plastic mechanisms of the neuronal

  3. Structural and functional reorganization of propriospinal connections promotes functional recovery after spinal cord injury

    Directory of Open Access Journals (Sweden)

    Linard Filli

    2015-01-01

    Full Text Available Axonal regeneration and fiber regrowth is limited in the adult central nervous system, but research over the last decades has revealed a high intrinsic capacity of brain and spinal cord circuits to adapt and reorganize after smaller injuries or denervation. Short-distance fiber growth and synaptic rewiring was found in cortex, brain stem and spinal cord and could be associated with restoration of sensorimotor functions that were impaired by the injury. Such processes of structural plasticity were initially observed in the corticospinal system following spinal cord injury or stroke, but recent studies showed an equally high potential for structural and functional reorganization in reticulospinal, rubrospinal or propriospinal projections. Here we review the lesion-induced plastic changes in the propriospinal pathways, and we argue that they represent a key mechanism triggering sensorimotor recovery upon incomplete spinal cord injury. The formation or strengthening of spinal detour pathways bypassing supraspinal commands around the lesion site to the denervated spinal cord were identified as prominent neural substrate inducing substantial motor recovery in different species from mice to primates. Indications for the existence of propriospinal bypasses were also found in humans after cortical stroke. It is mandatory for current research to dissect the biological mechanisms underlying spinal circuit remodeling and to investigate how these processes can be stimulated in an optimal way by therapeutic interventions (e.g., fiber-growth enhancing interventions, rehabilitation. This knowledge will clear the way for the development of novel strategies targeting the remarkable plastic potential of propriospinal circuits to maximize functional recovery after spinal cord injury.

  4. Resting‐state connectivity of pre‐motor cortex reflects disability in multiple sclerosis

    DEFF Research Database (Denmark)

    Dogonowski, Anne-Marie; Siebner, Hartwig Roman; Soelberg Sørensen, P.

    2013-01-01

    Objective To characterize the relationship between motor resting-state connectivity of the dorsal pre-motor cortex (PMd) and clinical disability in patients with multiple sclerosis (MS). Materials and methods A total of 27 patients with relapsing–remitting MS (RR-MS) and 15 patients with secondary...... be interpreted as adaptive reorganization of the motor system to maintain motor function, which appears to be limited to the relapsing–remitting stage of the disease....

  5. Functional organization of motor cortex of adult macaque monkeys is altered by sensory loss in infancy.

    Science.gov (United States)

    Qi, Hui-Xin; Jain, Neeraj; Collins, Christine E; Lyon, David C; Kaas, Jon H

    2010-02-16

    When somatosensory cortex (S1) is deprived of some of its inputs after section of ascending afferents in the dorsal columns of the spinal cord, it reorganizes to overrepresent the surviving inputs. As somatosensory cortex provides guiding sensory information to motor cortex, such sensory loss and representational reorganization could affect the development of the motor map in primary motor cortex (M1), especially if the sensory loss occurs early in development. To address this possibility, the dorsal columns of the spinal cord were sectioned between cervical levels (C3-5) 3-12 days after birth in five macaque monkeys. After 3-5 years of maturation (young adults), we determined how movements were represented in M1 contralateral to the lesion by using microelectrodes to electrically stimulate sites in M1 to evoke movements. Although the details of the motor maps in these five monkeys varied, the forelimb motor maps were abnormal. The representations of digit movements were reduced and abnormally arranged. Current levels for evoking movements from the forelimb region of M1 were in the normal range, but the lowest mean stimulation thresholds were for wrist or elbow instead of digit movements. Incomplete lesions and bilateral lesions produced fewer abnormalities. The results suggest that the development of normal motor cortex maps in M1 depends on sensory feedback from somatosensory maps.

  6. Expediting Scientific Data Analysis with Reorganization of Data

    Energy Technology Data Exchange (ETDEWEB)

    Byna, Surendra; Wu, Kesheng

    2013-08-19

    Data producers typically optimize the layout of data files to minimize the write time. In most cases, data analysis tasks read these files in access patterns different from the write patterns causing poor read performance. In this paper, we introduce Scientific Data Services (SDS), a framework for bridging the performance gap between writing and reading scientific data. SDS reorganizes data to match the read patterns of analysis tasks and enables transparent data reads from the reorganized data. We implemented a HDF5 Virtual Object Layer (VOL) plugin to redirect the HDF5 dataset read calls to the reorganized data. To demonstrate the effectiveness of SDS, we applied two parallel data organization techniques: a sort-based organization on a plasma physics data and a transpose-based organization on mass spectrometry imaging data. We also extended the HDF5 data access API to allow selection of data based on their values through a query interface, called SDS Query. We evaluated the execution time in accessing various subsets of data through existing HDF5 Read API and SDS Query. We showed that reading the reorganized data using SDS is up to 55X faster than reading the original data.

  7. 12 CFR 5.32 - Expedited procedures for certain reorganizations.

    Science.gov (United States)

    2010-01-01

    ... that the bank holding company will provide to the shareholders of the reorganizing bank for their shares of stock of the bank; (B) The date as of which the rights of each shareholder to participate in... national bank. (e) Rights of dissenting shareholders. Any shareholder of a bank who has voted against...

  8. Neuropsychology of prefrontal cortex

    OpenAIRE

    2008-01-01

    The history of clinical frontal lobe study is long and rich which provides valuable insights into neuropsychologic determinants of functions of prefrontal cortex (PFC). PFC is often classified as multimodal association cortex as extremely processed information from various sensory modalities is integrated here in a precise fashion to form the physiologic constructs of memory, perception, and diverse cognitive processes. Human neuropsychologic studies also support the notion of different funct...

  9. Why reorganization of firms fails: evidence from Estonia. Summary: Saneerimismenetluse ebaõnnestumise põhjused Eestis

    Directory of Open Access Journals (Sweden)

    Oliver Lukason

    2013-09-01

    Full Text Available Although most countries have firm reorganization option in legislation (either as a separate law or part of insolvency code, the practice of successful reorganizations has remained modest. Reorganization law was introduced in Estonia in late 2008, but only a few firms have been successfully reorganized since. Derived from previous the article studies, what are the reasons for firm reorganization failure. From legal viewpoint, main causes are found to be that firms under reorganization do not submit reorganization plans to court and the preconditions for reorganization lapse. The financial ratios for successful and unsuccessful reorganizations are not significantly different according to independent samples median test. Unsuccessfully reorganized firms perform worse than successful ones in the year before reorganization year, but the opposite phenomenon occurs two and three years before reorganization year.

  10. Clinical neurorehabilitation - implications of the Reorganization of Elementary Functions (REF) model

    DEFF Research Database (Denmark)

    Rytter, Hana Malá; Mogensen, Jesper

    The REF (Reorganization of Elementary Functions) model suggests mechanisms of posttraumatic reorganization, and resolves the contradiction between localization and functional recovery. In the process of developing this model, we have reconceptualised the term ‘function’ and introduced a concept...

  11. Cortical reorganization associated lower extremity motor recovery as evidenced by functional MRI and diffusion tensor tractography in a stroke patient.

    Science.gov (United States)

    Jang, Sung Ho; You, Sung H; Kwon, Yong-Hyun; Hallett, Mark; Lee, Mi Young; Ahn, Sang Ho

    2005-01-01

    Recovery mechanisms supporting upper extremity motor recovery following stroke are well established, but cortical mechanism associated with lower extremity motor recovery is unknown. The aim of this study was to assess cortical reorganization associated with lower extremity motor recovery in a hemiparetic patient. Six control subjects and a 17 year-old woman with left intracerebral hemorrhage due to an arterio-venous malformation rupture were evaluated. The motor function of the paretic (left) hip and knee had recovered slowly to the extent of her being able to overcome gravity for 10 months after the onset of stroke. However, her paretic upper extremity showed no significant motor recovery. Blood oxygenation level dependent (BOLD) functional MRI at 1.5 Tesla was used to determine the acutual location of cortical activation in the predefined regions of interest. Concurrently, Diffusion Tensor Imaging (DTI) in combination with a novel 3D-fiber reconstruction algorithm was utilized to investigate the pattern of the corticospinal pathway connectivity between the areas of the motor stream. All subjects' body parts were secured in the scanner and performed a sequential knee flexion-extension with a predetermined angle of 0-60 degrees at 0.5 Hz. Controls showed anticipated activation in the contralateral sensorimotor cortex (SM1) and the descending corticospinal fibers stemming from motor cortex. In contrast to control normal subjects, the stroke patient showed fMRI activation only in the unaffected (right) primary SM1 during either paretic or nonparetic knee movements. DTT fiber tracing data showed that the corticospinal tract fibers were found only in the unaffected hemisphere but not in the affected hemisphere. Our results indicate that an ipsilateral motor pathway from the unaffected (right) motor cortex to the paretic (right) leg was present in this patient. This study raises the potential that the contralesional (ipsilateral) SM1 is involved in cortical

  12. Spectral features control temporal plasticity in auditory cortex.

    Science.gov (United States)

    Kilgard, M P; Pandya, P K; Vazquez, J L; Rathbun, D L; Engineer, N D; Moucha, R

    2001-01-01

    Cortical responses are adjusted and optimized throughout life to meet changing behavioral demands and to compensate for peripheral damage. The cholinergic nucleus basalis (NB) gates cortical plasticity and focuses learning on behaviorally meaningful stimuli. By systematically varying the acoustic parameters of the sound paired with NB activation, we have previously shown that tone frequency and amplitude modulation rate alter the topography and selectivity of frequency tuning in primary auditory cortex. This result suggests that network-level rules operate in the cortex to guide reorganization based on specific features of the sensory input associated with NB activity. This report summarizes recent evidence that temporal response properties of cortical neurons are influenced by the spectral characteristics of sounds associated with cholinergic modulation. For example, repeated pairing of a spectrally complex (ripple) stimulus decreased the minimum response latency for the ripple, but lengthened the minimum latency for tones. Pairing a rapid train of tones with NB activation only increased the maximum following rate of cortical neurons when the carrier frequency of each train was randomly varied. These results suggest that spectral and temporal parameters of acoustic experiences interact to shape spectrotemporal selectivity in the cortex. Additional experiments with more complex stimuli are needed to clarify how the cortex learns natural sounds such as speech.

  13. 26 CFR 54.4980B-9 - Business reorganizations and employer withdrawals from multiemployer plans.

    Science.gov (United States)

    2010-04-01

    ...-9 Business reorganizations and employer withdrawals from multiemployer plans. The following... multiemployer plans: Q-1: For purposes of this section, what are a business reorganization, a stock sale, and an... 26 Internal Revenue 17 2010-04-01 2010-04-01 false Business reorganizations and...

  14. Temporal evolution of brain reorganization under cross-modal training: insights into the functional architecture of encoding and retrieval networks

    Science.gov (United States)

    Likova, Lora T.

    2015-03-01

    This study is based on the recent discovery of massive and well-structured cross-modal memory activation generated in the primary visual cortex (V1) of totally blind people as a result of novel training in drawing without any vision (Likova, 2012). This unexpected functional reorganization of primary visual cortex was obtained after undergoing only a week of training by the novel Cognitive-Kinesthetic Method, and was consistent across pilot groups of different categories of visual deprivation: congenitally blind, late-onset blind and blindfolded (Likova, 2014). These findings led us to implicate V1 as the implementation of the theoretical visuo-spatial 'sketchpad' for working memory in the human brain. Since neither the source nor the subsequent 'recipient' of this non-visual memory information in V1 is known, these results raise a number of important questions about the underlying functional organization of the respective encoding and retrieval networks in the brain. To address these questions, an individual totally blind from birth was given a week of Cognitive-Kinesthetic training, accompanied by functional magnetic resonance imaging (fMRI) both before and just after training, and again after a two-month consolidation period. The results revealed a remarkable temporal sequence of training-based response reorganization in both the hippocampal complex and the temporal-lobe object processing hierarchy over the prolonged consolidation period. In particular, a pattern of profound learning-based transformations in the hippocampus was strongly reflected in V1, with the retrieval function showing massive growth as result of the Cognitive-Kinesthetic memory training and consolidation, while the initially strong hippocampal response during tactile exploration and encoding became non-existent. Furthermore, after training, an alternating patch structure in the form of a cascade of discrete ventral regions underwent radical transformations to reach complete functional

  15. Olfactory consciousness and gamma oscillation couplings across the olfactory bulb, olfactory cortex, and orbitofrontal cortex.

    Science.gov (United States)

    Mori, Kensaku; Manabe, Hiroyuki; Narikiyo, Kimiya; Onisawa, Naomi

    2013-01-01

    The orbitofrontal cortex receives multi-modality sensory inputs, including olfactory input, and is thought to be involved in conscious perception of the olfactory image of objects. Generation of olfactory consciousness may require neuronal circuit mechanisms for the "binding" of distributed neuronal activities, with each constituent neuron representing a specific component of an olfactory percept. The shortest neuronal pathway for odor signals to reach the orbitofrontal cortex is olfactory sensory neuron-olfactory bulb-olfactory cortex-orbitofrontal cortex, but other pathways exist, including transthalamic pathways. Here, we review studies on the structural organization and functional properties of the shortest pathway, and propose a model of neuronal circuit mechanisms underlying the temporal bindings of distributed neuronal activities in the olfactory cortex. We describe a hypothesis that suggests functional roles of gamma oscillations in the bindings. This hypothesis proposes that two types of projection neurons in the olfactory bulb, tufted cells and mitral cells, play distinct functional roles in bindings at neuronal circuits in the olfactory cortex: tufted cells provide specificity-projecting circuits which send odor information with early-onset fast gamma synchronization, while mitral cells give rise to dispersedly-projecting feed-forward binding circuits which transmit the response synchronization timing with later-onset slow gamma synchronization. This hypothesis also suggests a sequence of bindings in the olfactory cortex: a small-scale binding by the early-phase fast gamma synchrony of tufted cell inputs followed by a larger-scale binding due to the later-onset slow gamma synchrony of mitral cell inputs. We discuss that behavioral state, including wakefulness and sleep, regulates gamma oscillation couplings across the olfactory bulb, olfactory cortex, and orbitofrontal cortex.

  16. Olfactory consciousness and gamma oscillation couplings across the olfactory bulb, olfactory cortex and orbitofrontal cortex

    Directory of Open Access Journals (Sweden)

    Kensaku eMori

    2013-10-01

    Full Text Available The orbitofrontal cortex receives multi-modality sensory inputs, including olfactory input, and is thought to be involved in conscious perception of the olfactory image of objects. Generation of olfactory consciousness requires neuronal circuit mechanisms for the ‘binding’ of distributed neuronal activities, with each constituent neuron representing a specific component of an olfactory percept. The shortest neuronal pathway for odor signals to reach the orbitofrontal cortex is olfactory sensory neuron – olfactory bulb – olfactory cortex – orbitofrontal cortex, but other pathways exist, including transthalamic pathways. Here, we review studies on the structural organization and functional properties of the shortest pathway, and propose a model of neuronal circuit mechanisms underlying the temporal bindings of distributed neuronal activities in the olfactory cortex. We describe a hypothesis that suggests functional roles of gamma oscillations in the bindings. This hypothesis proposes that two types of projection neurons in the olfactory bulb, tufted cells and mitral cells, play distinct functional roles in bindings at neuronal circuits in the olfactory cortex: tufted cells provide specificity-projecting circuits which send odor information with early-onset fast gamma synchronization, while mitral cells give rise to dispersedly-projecting feed-forward binding circuits which transmit the response synchronization timing with later-onset slow gamma synchronization. This hypothesis also suggests a sequence of bindings in the olfactory cortex: a small-scale binding by the early-phase fast gamma synchrony of tufted cell inputs followed by a larger-scale binding due to the later-onset slow gamma synchrony of mitral cell inputs. We discuss that behavioral state, including wakefulness and sleep, regulates gamma oscillation couplings across the olfactory bulb, olfactory cortex, and orbitofrontal cortex.

  17. Detecting Cortex Fragments During Bacterial Spore Germination.

    Science.gov (United States)

    Francis, Michael B; Sorg, Joseph A

    2016-06-25

    The process of endospore germination in Clostridium difficile, and other Clostridia, increasingly is being found to differ from the model spore-forming bacterium, Bacillus subtilis. Germination is triggered by small molecule germinants and occurs without the need for macromolecular synthesis. Though differences exist between the mechanisms of spore germination in species of Bacillus and Clostridium, a common requirement is the hydrolysis of the peptidoglycan-like cortex which allows the spore core to swell and rehydrate. After rehydration, metabolism can begin and this, eventually, leads to outgrowth of a vegetative cell. The detection of hydrolyzed cortex fragments during spore germination can be difficult and the modifications to the previously described assays can be confusing or difficult to reproduce. Thus, based on our recent report using this assay, we detail a step-by-step protocol for the colorimetric detection of cortex fragments during bacterial spore germination.

  18. End-group Influence on the Frontier Molecular Orbital Reorganization in Molecular Junctions -- Effect on Thermopower

    Science.gov (United States)

    Balachandran, Janakiraman; Reddy, Pramod; Dunietz, Barry; Gavini, Vikram

    2014-03-01

    The frontier molecular orbital (FMO) reorganization and in turn on the thermopower of the aromatic molecules trapped between metal electrodes (aka molecular junctions) depends on two effects namely (1) the stabilization effect - due to the physical presence of the metal electrode atoms and (2) change in e-e interactions - due to end-group mediated charge transfer. The stabilization effect always reduces the FMO energies. The charge transfer effect increases the FMO energies in charge-gaining molecules, which in turn opposes the stabilization effect resulting in a small overall shift. However, the charge transfer effect decreases the FMO energies in charge-losing molecules, which in turn complements the stabilization effect resulting in a large overall downward shift. This hypothesis is validated by delineating the shifts due to stabilization and charge-transfer effects independently. Further we also demonstrate the generality of the hypothesis by applying it on a wide range of aromatic molecules with different length and end-groups. Finally, we also present computationally efficient strategies, based on the proposed mechanism, to quantitatively compute the FMO reorganization which in turn has potential for high throughput analysis of molecular junctions.

  19. Reorganization and enhanced functional connectivity of motor areas in repetitive ankle movements after training in locomotor attention.

    Science.gov (United States)

    Sacco, Katiuscia; Katiuscia, Sacco; Cauda, Franco; Franco, Cauda; D'Agata, Federico; Federico, D'Agata; Mate, Davide; Davide, Mate; Duca, Sergio; Sergio, Duca; Geminiani, Giuliano; Giuliano, Geminiani

    2009-11-10

    We examined the functional changes in the activity of the cerebral areas involved in motor tasks, prior to and following a 1-week period of locomotor attention training consisting of physical and mental practice, in normal subjects. In a previous study, we examined the effect of the same kind of training on motor circuits using an fMRI paradigm of motor imagery. In this work, we investigated whether the expanded activations found in the previous study were present also using an overt foot motor task consisting of ankle dorsiflexion; a control task requiring hand movements was also administered. In this article, we also discuss the changes in functional connectivity between the pretraining and posttraining conditions during foot movements. The foot task showed a posttraining reorganization of the sensorimotor areas, which is in line with earlier studies on lower limb motor learning, while the control hand movement task only produced a modification in the left premotor cortex. These results confirm the effect of training on functional reorganization and underline its task specificity. After training, we also observed enhanced connectivity in the sensorimotor areas, suggesting that functional connectivity of the sensorimotor network can be modulated by focusing attention on the movements involved in ambulation.

  20. Workplace Re-organization and Changes in Physiological Stress Markers

    DEFF Research Database (Denmark)

    Carlsson, Rikke Hinge; Hansen, Åse Marie; Kristiansen, Jesper

    2014-01-01

    The aim of this study was to investigate changes in physiological stress markers as a consequence of workplace reorganization. Moreover, we aimed to investigate changes in the psychosocial work environment (job strain, effortreward imbalance (ERI), in psychological distress (stress symptoms......, perceived stress) and the mediating effect of these factors on changes in physiological stress markers. We used data from a longitudinal study that studied the health consequences of a major reorganization of non-state public offices executed in Denmark on 1 January 2007. Collection of clinical...... and questionnaire data was in 2006 and 2008, and in this sub-study we included 359 participants. To reflect stress reactions of the autonomic nervous system, the endocrine system and the immune system, we included 13 physiological markers. We observed significant change in several physiological stress markers...

  1. A self-reorganizing digital flight control system for aircraft

    Science.gov (United States)

    Montgomery, R. C.; Caglayan, A. K.

    1974-01-01

    This paper presents a design method for digital self-reorganizing control systems which is optimally tolerant of failures in aircraft sensors. The functions of this system are accomplished with software instead of the popular and costly technique of hardware duplication. The theoretical development, based on M-ary hypothesis testing, results in a bank of M Kalman filters operating in parallel in the failure detection logic. A moving window of the innovations of each Kalman filter drives the detection logic to decide the failure state of the system. The detection logic also selects the optimal state estimate (for control logic) from the bank of Kalman filters. The design process is applied to the design of a self-reorganizing control system for a current configuration of the space shuttle orbiter at Mach 5 and 120,000 feet. The failure detection capabilities of the system are demonstrated using a real-time simulation of the system with noisy sensors.

  2. Reorganizing Geographic Combatant Command Headquarters for Joint Force 2020

    Science.gov (United States)

    2013-05-01

    Commander’s Initiative Group, or CIG . Finally, Jeffrey R. Immelt (CEO from 2001-Present) first reorganized eleven business units into thirteen, and...Resources, Intelligence, Rule of Law, and Communication. COMISAF’s special staff includes the Commander’s Initiative Group ( CIG ), Legislative...the COS (18 reporting entities). The special staff group consists of the Commander’s Initiative Group ( CIG ), IG, Judge Advocate, Legislative Affairs

  3. Enhancing Physical Activity and Brain Reorganization after Stroke

    OpenAIRE

    2011-01-01

    It is becoming increasingly clear that, if reorganization of brain function is to be optimal after stroke, there needs to be a reorganisation of the methods used in physical rehabilitation and the time spent in specific task practice, strength and endurance training, and aerobic exercise. Frequency and intensity of rehabilitation need to be increased so that patients can gain the energy levels and vigour necessary for participation in physical activity both during rehabilitation and after dis...

  4. Representation of Reward Feedback in Primate Auditory Cortex

    Directory of Open Access Journals (Sweden)

    Michael eBrosch

    2011-02-01

    Full Text Available It is well established that auditory cortex is plastic on different time scales and that this plasticity is driven by the reinforcement that is used to motivate subjects to learn or to perform an auditory task. Motivated by these findings, we study in detail properties of neuronal firing in auditory cortex that is related to reward feedback. We recorded from the auditory cortex of two monkeys while they were performing an auditory categorization task. Monkeys listened to a sequence of tones and had to signal when the frequency of adjacent tones stepped in downward direction, irrespective of the tone frequency and step size. Correct identifications were rewarded with either a large or a small amount of water. The size of reward depended on the monkeys' performance in the previous trial: it was large after a correct trial and small after an incorrect trial. The rewards served to maintain task performance. During task performance we found three successive periods of neuronal firing in auditory cortex that reflected (1 the reward expectancy for each trial, (2 the reward size received and (3 the mismatch between the expected and delivered reward. These results, together with control experiments suggest that auditory cortex receives reward feedback that could be used to adapt auditory cortex to task requirements. Additionally, the results presented here extend previous observations of non-auditory roles of auditory cortex and shows that auditory cortex is even more cognitively influenced than lately recognized.

  5. Representation of reward feedback in primate auditory cortex.

    Science.gov (United States)

    Brosch, Michael; Selezneva, Elena; Scheich, Henning

    2011-01-01

    It is well established that auditory cortex is plastic on different time scales and that this plasticity is driven by the reinforcement that is used to motivate subjects to learn or to perform an auditory task. Motivated by these findings, we study in detail properties of neuronal firing in auditory cortex that is related to reward feedback. We recorded from the auditory cortex of two monkeys while they were performing an auditory categorization task. Monkeys listened to a sequence of tones and had to signal when the frequency of adjacent tones stepped in downward direction, irrespective of the tone frequency and step size. Correct identifications were rewarded with either a large or a small amount of water. The size of reward depended on the monkeys' performance in the previous trial: it was large after a correct trial and small after an incorrect trial. The rewards served to maintain task performance. During task performance we found three successive periods of neuronal firing in auditory cortex that reflected (1) the reward expectancy for each trial, (2) the reward-size received, and (3) the mismatch between the expected and delivered reward. These results, together with control experiments suggest that auditory cortex receives reward feedback that could be used to adapt auditory cortex to task requirements. Additionally, the results presented here extend previous observations of non-auditory roles of auditory cortex and shows that auditory cortex is even more cognitively influenced than lately recognized.

  6. Neural activation patterns of successful episodic encoding: Reorganization during childhood, maintenance in old age

    Directory of Open Access Journals (Sweden)

    Yee Lee Shing

    2016-08-01

    Full Text Available The two-component framework of episodic memory (EM development posits that the contributions of medial temporal lobe (MTL and prefrontal cortex (PFC to successful encoding differ across the lifespan. To test the framework’s hypotheses, we compared subsequent memory effects (SME of 10–12 year-old children, younger adults, and older adults using functional magnetic resonance imaging (fMRI. Memory was probed by cued recall, and SME were defined as regional activation differences during encoding between subsequently correctly recalled versus omitted items. In MTL areas, children’s SME did not differ in magnitude from those of younger and older adults. In contrast, children’s SME in PFC were weaker than the corresponding SME in younger and older adults, in line with the hypothesis that PFC contributes less to successful encoding in childhood. Differences in SME between younger and older adults were negligible. The present results suggest that, among individuals with high memory functioning, the neural circuitry contributing to successful episodic encoding is reorganized from middle childhood to adulthood. Successful episodic encoding in later adulthood, however, is characterized by the ability to maintain the activation patterns that emerged in young adulthood.

  7. Combined Cognitive-Psychological-Physical Intervention Induces Reorganization of Intrinsic Functional Brain Architecture in Older Adults

    Directory of Open Access Journals (Sweden)

    Zhiwei Zheng

    2015-01-01

    Full Text Available Mounting evidence suggests that enriched mental, physical, and socially stimulating activities are beneficial for counteracting age-related decreases in brain function and cognition in older adults. Here, we used functional magnetic resonance imaging (fMRI to demonstrate the functional plasticity of brain activity in response to a combined cognitive-psychological-physical intervention and investigated the contribution of the intervention-related brain changes to individual performance in healthy older adults. The intervention was composed of a 6-week program of combined activities including cognitive training, Tai Chi exercise, and group counseling. The results showed improved cognitive performance and reorganized regional homogeneity of spontaneous fluctuations in the blood oxygen level-dependent (BOLD signals in the superior and middle temporal gyri, and the posterior lobe of the cerebellum, in the participants who attended the intervention. Intriguingly, the intervention-induced changes in the coherence of local spontaneous activity correlated with the improvements in individual cognitive performance. Taken together with our previous findings of enhanced resting-state functional connectivity between the medial prefrontal cortex and medial temporal lobe regions following a combined intervention program in older adults, we conclude that the functional plasticity of the aging brain is a rather complex process, and an effective cognitive-psychological-physical intervention is helpful for maintaining a healthy brain and comprehensive cognition during old age.

  8. Combined cognitive-psychological-physical intervention induces reorganization of intrinsic functional brain architecture in older adults.

    Science.gov (United States)

    Zheng, Zhiwei; Zhu, Xinyi; Yin, Shufei; Wang, Baoxi; Niu, Yanan; Huang, Xin; Li, Rui; Li, Juan

    2015-01-01

    Mounting evidence suggests that enriched mental, physical, and socially stimulating activities are beneficial for counteracting age-related decreases in brain function and cognition in older adults. Here, we used functional magnetic resonance imaging (fMRI) to demonstrate the functional plasticity of brain activity in response to a combined cognitive-psychological-physical intervention and investigated the contribution of the intervention-related brain changes to individual performance in healthy older adults. The intervention was composed of a 6-week program of combined activities including cognitive training, Tai Chi exercise, and group counseling. The results showed improved cognitive performance and reorganized regional homogeneity of spontaneous fluctuations in the blood oxygen level-dependent (BOLD) signals in the superior and middle temporal gyri, and the posterior lobe of the cerebellum, in the participants who attended the intervention. Intriguingly, the intervention-induced changes in the coherence of local spontaneous activity correlated with the improvements in individual cognitive performance. Taken together with our previous findings of enhanced resting-state functional connectivity between the medial prefrontal cortex and medial temporal lobe regions following a combined intervention program in older adults, we conclude that the functional plasticity of the aging brain is a rather complex process, and an effective cognitive-psychological-physical intervention is helpful for maintaining a healthy brain and comprehensive cognition during old age.

  9. Neural activation patterns of successful episodic encoding: Reorganization during childhood, maintenance in old age.

    Science.gov (United States)

    Shing, Yee Lee; Brehmer, Yvonne; Heekeren, Hauke R; Bäckman, Lars; Lindenberger, Ulman

    2016-08-01

    The two-component framework of episodic memory (EM) development posits that the contributions of medial temporal lobe (MTL) and prefrontal cortex (PFC) to successful encoding differ across the lifespan. To test the framework's hypotheses, we compared subsequent memory effects (SME) of 10-12 year-old children, younger adults, and older adults using functional magnetic resonance imaging (fMRI). Memory was probed by cued recall, and SME were defined as regional activation differences during encoding between subsequently correctly recalled versus omitted items. In MTL areas, children's SME did not differ in magnitude from those of younger and older adults. In contrast, children's SME in PFC were weaker than the corresponding SME in younger and older adults, in line with the hypothesis that PFC contributes less to successful encoding in childhood. Differences in SME between younger and older adults were negligible. The present results suggest that, among individuals with high memory functioning, the neural circuitry contributing to successful episodic encoding is reorganized from middle childhood to adulthood. Successful episodic encoding in later adulthood, however, is characterized by the ability to maintain the activation patterns that emerged in young adulthood.

  10. Dispersal governs the reorganization of ecological networks under environmental change.

    Science.gov (United States)

    Thompson, Patrick L; Gonzalez, Andrew

    2017-05-08

    Ecological networks, such as food webs, mutualist webs and host-parasite webs, are reorganizing as species abundances and spatial distributions shift in response to environmental change. Current theoretical expectations for how this reorganization will occur are available for competition or for parts of interaction networks, but these may not extend to more complex networks. Here we use metacommunity theory to develop new expectations for how complex networks will reorganize under environmental change, and show that dispersal is crucial for determining the degree to which networks will retain their composition and structure. When dispersal between habitat patches is low, all types of species interactions act as a strong determinant for whether species can colonize suitable habitats. This colonization resistance drives species turnover, which breaks apart current networks and leads to the formation of new networks. However, when dispersal rates are increased, colonists arrive in high abundance in habitats where they are well adapted, so interactions with resident species contribute less to colonization success. Dispersal ensures that species associations are maintained as they shift in space, so networks retain similar composition and structure. The crucial role of dispersal reinforces the need to manage habitat connectivity to sustain species and interaction diversity into the future.

  11. Interframe hierarchical vector quantization using hashing-based reorganized codebook

    Science.gov (United States)

    Choo, Chang Y.; Cheng, Che H.; Nasrabadi, Nasser M.

    1995-12-01

    Real-time multimedia communication over PSTN (Public Switched Telephone Network) or wireless channel requires video signals to be encoded at the bit rate well below 64 kbits/second. Most of the current works on such very low bit rate video coding are based on H.261 or H.263 scheme. The H.263 encoding scheme, for example, consists mainly of motion estimation and compensation, discrete cosine transform, and run and variable/fixed length coding. Vector quantization (VQ) is an efficient and alternative scheme for coding at very low bit rate. One such VQ code applied to video coding is interframe hierarchical vector quantization (IHVQ). One problem of IHVQ, and VQ in general, is the computational complexity due to codebook search. A number of techniques have been proposed to reduce the search time which include tree-structured VQ, finite-state VQ, cache VQ, and hashing based codebook reorganization. In this paper, we present an IHVQ code with a hashing based scheme to reorganize the codebook so that codebook search time, and thus encoding time, can be significantly reduced. We applied the algorithm to the same test environment as in H.263 and evaluated coding performance. It turned out that the performance of the proposed scheme is significantly better than that of IHVQ without hashed codebook. Also, the performance of the proposed scheme was comparable to and often better than that of the H.263, due mainly to hashing based reorganized codebook.

  12. A molecularly based theory for electron transfer reorganization energy

    Energy Technology Data Exchange (ETDEWEB)

    Zhuang, Bilin; Wang, Zhen-Gang, E-mail: zgw@cheme.caltech.edu [Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125 (United States)

    2015-12-14

    Using field-theoretic techniques, we develop a molecularly based dipolar self-consistent-field theory (DSCFT) for charge solvation in pure solvents under equilibrium and nonequilibrium conditions and apply it to the reorganization energy of electron transfer reactions. The DSCFT uses a set of molecular parameters, such as the solvent molecule’s permanent dipole moment and polarizability, thus avoiding approximations that are inherent in treating the solvent as a linear dielectric medium. A simple, analytical expression for the free energy is obtained in terms of the equilibrium and nonequilibrium electrostatic potential profiles and electric susceptibilities, which are obtained by solving a set of self-consistent equations. With no adjustable parameters, the DSCFT predicts activation energies and reorganization energies in good agreement with previous experiments and calculations for the electron transfer between metallic ions. Because the DSCFT is able to describe the properties of the solvent in the immediate vicinity of the charges, it is unnecessary to distinguish between the inner-sphere and outer-sphere solvent molecules in the calculation of the reorganization energy as in previous work. Furthermore, examining the nonequilibrium free energy surfaces of electron transfer, we find that the nonequilibrium free energy is well approximated by a double parabola for self-exchange reactions, but the curvature of the nonequilibrium free energy surface depends on the charges of the electron-transferring species, contrary to the prediction by the linear dielectric theory.

  13. Hecate/Grip2a acts to reorganize the cytoskeleton in the symmetry-breaking event of embryonic axis induction.

    Directory of Open Access Journals (Sweden)

    Xiaoyan Ge

    2014-06-01

    Full Text Available Maternal homozygosity for three independent mutant hecate alleles results in embryos with reduced expression of dorsal organizer genes and defects in the formation of dorsoanterior structures. A positional cloning approach identified all hecate mutations as stop codons affecting the same gene, revealing that hecate encodes the Glutamate receptor interacting protein 2a (Grip2a, a protein containing multiple PDZ domains known to interact with membrane-associated factors including components of the Wnt signaling pathway. We find that grip2a mRNA is localized to the vegetal pole of the oocyte and early embryo, and that during egg activation this mRNA shifts to an off-center vegetal position corresponding to the previously proposed teleost cortical rotation. hecate mutants show defects in the alignment and bundling of microtubules at the vegetal cortex, which result in defects in the asymmetric movement of wnt8a mRNA as well as anchoring of the kinesin-associated cargo adaptor Syntabulin. We also find that, although short-range shifts in vegetal signals are affected in hecate mutant embryos, these mutants exhibit normal long-range, animally directed translocation of cortically injected dorsal beads that occurs in lateral regions of the yolk cortex. Furthermore, we show that such animally-directed movement along the lateral cortex is not restricted to a single arc corresponding to the prospective dorsal region, but occur in multiple meridional arcs even in opposite regions of the embryo. Together, our results reveal a role for Grip2a function in the reorganization and bundling of microtubules at the vegetal cortex to mediate a symmetry-breaking short-range shift corresponding to the teleost cortical rotation. The slight asymmetry achieved by this directed process is subsequently amplified by a general cortical animally-directed transport mechanism that is neither dependent on hecate function nor restricted to the prospective dorsal axis.

  14. Electrochemical Electron Transfer and Proton-Coupled Electron Transfer: Effects of Double Layer and Ionic Environment on Solvent Reorganization Energies

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Soumya; Soudackov, Alexander; Hammes-Schiffer, Sharon

    2016-06-14

    Electron transfer and proton coupled electron transfer (PCET) reactions at electrochemical interfaces play an essential role in a broad range of energy conversion processes. The reorganization energy, which is a measure of the free energy change associated with solute and solvent rearrangements, is a key quantity for calculating rate constants for these reactions. We present a computational method for including the effects of the double layer and ionic environment of the diffuse layer in calculations of electrochemical solvent reorganization energies. This approach incorporates an accurate electronic charge distribution of the solute within a molecular-shaped cavity in conjunction with a dielectric continuum treatment of the solvent, ions, and electrode using the integral equations formalism polarizable continuum model. The molecule-solvent boundary is treated explicitly, but the effects of the electrode-double layer and double layer-diffuse layer boundaries, as well as the effects of the ionic strength of the solvent, are included through an external Green’s function. The calculated total reorganization energies agree well with experimentally measured values for a series of electrochemical systems, and the effects of including both the double layer and ionic environment are found to be very small. This general approach was also extended to electrochemical PCET and produced total reorganization energies in close agreement with experimental values for two experimentally studied PCET systems. This research was supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center, funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences.

  15. [Neuroanatomy of Frontal Association Cortex].

    Science.gov (United States)

    Takada, Masahiko

    2016-11-01

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

  16. INTERACTION BETWEEN MODELS OF THE LIFE CYCLE OF INDUSTRIAL ENTERPRISE AND CYCLE OF ITS REORGANIZATION

    Directory of Open Access Journals (Sweden)

    Chulkov Vitaliy Olegovich

    2012-10-01

    Full Text Available The objective of this scientific research is to develop a theoretical model of organizational and technology-related processes of reorganization of industrial enterprises, as well as their interaction. Multipoint logic notions of growth and interaction phases are used as research methods. The author describes the basic stages of reorganization, the life cycle of industrial enterprises and the cycle of their transformation. The processes are presented as an infographical image that represents a concentric model of interaction. This concentric model represents interaction between two or more phases. The process is entitled infografical modeling on the polyfunctional level. The concentric model moves both clockwise and anti-clockwise. Basic organizational and technological processes of reorganization of industrial enterprises that include decision making in terms of expediency of reorganization, design, construction, and performance of industrial enterprises at full capacity, and further operation of the industrial enterprise are described in the paper. Attainment of this objective, namely, reorganization of an industrial enterprise, involves a huge amount of resources, including labour resources that need interaction with all parties of reorganization; therefore, the concentric model of interaction describing the basic cycle of reorganization, the life cycle of an industrial enterprise and the cycle of its conversion is a trustworthy representation of this process. The proposed concentric model of interaction should be used in the design of organizational and technology-related processes for integrated consideration of reorganization of enterprises required to understand and improve the efficiency of reorganizations and to control the reorganization of industrial facilities.

  17. Mild sensory stimulation completely protects the adult rodent cortex from ischemic stroke.

    Directory of Open Access Journals (Sweden)

    Christopher C Lay

    Full Text Available Despite progress in reducing ischemic stroke damage, complete protection remains elusive. Here we demonstrate that, after permanent occlusion of a major cortical artery (middle cerebral artery; MCA, single whisker stimulation can induce complete protection of the adult rat cortex, but only if administered within a critical time window. Animals that receive early treatment are histologically and behaviorally equivalent to healthy controls and have normal neuronal function. Protection of the cortex clearly requires reperfusion to the ischemic area despite permanent occlusion. Using blood flow imaging and other techniques we found evidence of reversed blood flow into MCA branches from an alternate arterial source via collateral vessels (inter-arterial connections, a potential mechanism for reperfusion. These findings suggest that the cortex is capable of extensive blood flow reorganization and more importantly that mild sensory stimulation can provide complete protection from impending stroke given early intervention. Such non-invasive, non-pharmacological intervention has clear translational potential.

  18. Neural Patterns of Reorganization after Intensive Robot-Assisted Virtual Reality Therapy and Repetitive Task Practice in Patients with Chronic Stroke.

    Science.gov (United States)

    Saleh, Soha; Fluet, Gerard; Qiu, Qinyin; Merians, Alma; Adamovich, Sergei V; Tunik, Eugene

    2017-01-01

    Several approaches to rehabilitation of the hand following a stroke have emerged over the last two decades. These treatments, including repetitive task practice (RTP), robotically assisted rehabilitation and virtual rehabilitation activities, produce improvements in hand function but have yet to reinstate function to pre-stroke levels-which likely depends on developing the therapies to impact cortical reorganization in a manner that favors or supports recovery. Understanding cortical reorganization that underlies the above interventions is therefore critical to inform how such therapies can be utilized and improved and is the focus of the current investigation. Specifically, we compare neural reorganization elicited in stroke patients participating in two interventions: a hybrid of robot-assisted virtual reality (RAVR) rehabilitation training and a program of RTP training. Ten chronic stroke subjects participated in eight 3-h sessions of RAVR therapy. Another group of nine stroke subjects participated in eight sessions of matched RTP therapy. Functional magnetic resonance imaging (fMRI) data were acquired during paretic hand movement, before and after training. We compared the difference between groups and sessions (before and after training) in terms of BOLD intensity, laterality index of activation in sensorimotor areas, and the effective connectivity between ipsilesional motor cortex (iMC), contralesional motor cortex, ipsilesional primary somatosensory cortex (iS1), ipsilesional ventral premotor area (iPMv), and ipsilesional supplementary motor area. Last, we analyzed the relationship between changes in fMRI data and functional improvement measured by the Jebsen Taylor Hand Function Test (JTHFT), in an attempt to identify how neurophysiological changes are related to motor improvement. Subjects in both groups demonstrated motor recovery after training, but fMRI data revealed RAVR-specific changes in neural reorganization patterns. First, BOLD signal in multiple

  19. Neural Patterns of Reorganization after Intensive Robot-Assisted Virtual Reality Therapy and Repetitive Task Practice in Patients with Chronic Stroke

    Directory of Open Access Journals (Sweden)

    Soha Saleh

    2017-09-01

    Full Text Available Several approaches to rehabilitation of the hand following a stroke have emerged over the last two decades. These treatments, including repetitive task practice (RTP, robotically assisted rehabilitation and virtual rehabilitation activities, produce improvements in hand function but have yet to reinstate function to pre-stroke levels—which likely depends on developing the therapies to impact cortical reorganization in a manner that favors or supports recovery. Understanding cortical reorganization that underlies the above interventions is therefore critical to inform how such therapies can be utilized and improved and is the focus of the current investigation. Specifically, we compare neural reorganization elicited in stroke patients participating in two interventions: a hybrid of robot-assisted virtual reality (RAVR rehabilitation training and a program of RTP training. Ten chronic stroke subjects participated in eight 3-h sessions of RAVR therapy. Another group of nine stroke subjects participated in eight sessions of matched RTP therapy. Functional magnetic resonance imaging (fMRI data were acquired during paretic hand movement, before and after training. We compared the difference between groups and sessions (before and after training in terms of BOLD intensity, laterality index of activation in sensorimotor areas, and the effective connectivity between ipsilesional motor cortex (iMC, contralesional motor cortex, ipsilesional primary somatosensory cortex (iS1, ipsilesional ventral premotor area (iPMv, and ipsilesional supplementary motor area. Last, we analyzed the relationship between changes in fMRI data and functional improvement measured by the Jebsen Taylor Hand Function Test (JTHFT, in an attempt to identify how neurophysiological changes are related to motor improvement. Subjects in both groups demonstrated motor recovery after training, but fMRI data revealed RAVR-specific changes in neural reorganization patterns. First, BOLD

  20. Dielectric image effects in environmental reorganization free energies and inter-reactant work terms of metalloprotein electron transfer reactions

    Science.gov (United States)

    Kharkats, Yurij I.; Ulstrup, Jens

    1990-02-01

    Kinetics of electron transfer between redox metalloproteins and small inorganic reaction partners has become a powerful tool for investigations of protein electron transport. We introduce here a model for metalloprotein electron transfer which incorporates essential features omitted in previous approaches to metalloprotein electron transfer data analysis. The protein is represented by a spherical region of low dielectric constant, with a conducting sphere excentrically located inside the protein simulating the metal centre. A conducting sphere outside the protein represents the small reaction partners, and the whole system is embedded in a dielectric solvent. The inter-reactant work terms and overall protein and solvent reorganization free energy for this model have been calculated. It appears that dielectric image interactions for multiply charged small reactants are important and comparable to interactions with both the protein surface charges and the solvent. The character of work terms and reorganization free energies for proteins is thus different from those of small ionic reactants. Cross relations and other frames where these features are disregarded should therefore be used with care for protein electron transfer.

  1. Regulating prefrontal cortex activation

    DEFF Research Database (Denmark)

    Aznar, Susana; Klein, Anders Bue

    2013-01-01

    of emotion-based actions, such as addiction and other impulse-related behaviors. In this review, we give an overview of the 5-HT2A receptor distribution (neuronal, intracellular, and anatomical) along with its functional and physiological effect on PFC activation, and how that relates to more recent findings......The prefrontal cortex (PFC) is involved in mediating important higher-order cognitive processes such as decision making, prompting thereby our actions. At the same time, PFC activation is strongly influenced by emotional reactions through its functional interaction with the amygdala...... is highly expressed in the prefrontal cortex areas, playing an important role in modulating cortical activity and neural oscillations (brain waves). This makes it an interesting potential pharmacological target for the treatment of neuropsychiatric modes characterized by lack of inhibitory control...

  2. Global Dynamic Numerical Simulations of Plate Tectonic Reorganizations

    Science.gov (United States)

    Morra, G.; Quevedo, L.; Butterworth, N.; Matthews, K. J.; Müller, D.

    2010-12-01

    We use a new numerical approach for global geodynamics to investigate the origin of present global plate motion and to identify the causes of the last two global tectonic reorganizations occurred about 50 and 100 million years ago (Ma) [1]. While the 50 Ma event is the most well-known global plate-mantle event, expressed by the bend in the Hawaiian-Emperor volcanic chain, a prominent plate reorganization at about 100 Ma, although presently little studied, is clearly indicated by a major bend in the fracture zones in the Indian Ocean and by a change in Pacific plate motion [2]. Our workflow involves turning plate reconstructions into surface meshes that are subsequently employed as initial conditions for global Boundary Element numerical models. The tectonic setting that anticipates the reorganizations is processed with the software GPlates, combining the 3D mesh of the paleo-plate morphology and the reconstruction of paleo-subducted slabs, elaborated from tectonic history [3]. All our models involve the entire planetary system, are fully dynamic, have free surface, are characterized by a spectacular computational speed due to the simultaneous use of the multi-pole algorithm and the Boundary Element formulation and are limited only by the use of sharp material property variations [4]. We employ this new tool to unravel the causes of plate tectonic reorganizations, producing and comparing global plate motion with the reconstructed ones. References: [1] Torsvik, T., Müller, R.D., Van der Voo, R., Steinberger, B., and Gaina, C., 2008, Global Plate Motion Frames: Toward a unified model: Reviews in Geophysics, VOL. 46, RG3004, 44 PP., 2008 [2] Wessel, P. and Kroenke, L.W. Pacific absolute plate motion since 145 Ma: An assessment of the fixed hot spot hypothesis. Journal of Geophysical Research, Vol 113, B06101, 2008 [3] L. Quevedo, G. Morra, R. D. Mueller. Parallel Fast Multipole Boundary Element Method for Crustal Dynamics, Proceeding 9th World Congress and 4th Asian

  3. fMRI as a molecular imaging procedure for the functional reorganization of motor systems in chronic stroke

    Science.gov (United States)

    LAZARIDOU, ASIMINA; ASTRAKAS, LOUKAS; MINTZOPOULOS, DIONYSSIOS; KHANCHICEH, AZADEH; SINGHAL, ANEESH; MOSKOWITZ, MICHAEL; ROSEN, BRUCE; TZIKA, ARIA

    2013-01-01

    Previous brain imaging studies suggest that stroke alters functional connectivity in motor execution networks. Moreover, current understanding of brain plasticity has led to new approaches in stroke rehabilitation. Recent studies showed a significant role of effective coupling of neuronal activity in the SMA (supplementary motor area) and M1 (primary motor cortex) network for motor outcome in patients after stroke. After a subcortical stroke, functional magnetic resonance imaging (fMRI) during movement reveals cortical reorganization that is associated with the recovery of function. The aim of the present study was to explore connectivity alterations within the motor-related areas combining motor fMRI with a novel MR-compatible hand-induced robotic device (MR_CHIROD) training. Patients completed training at home and underwent serial MR evaluation at baseline and after 8 weeks of training. Training at home consisted of squeezing a gel exercise ball with the paretic hand at ~75% of maximum strength for 1 h/day, 3 days/week. The fMRI analysis revealed alterations in M1, SMA, PMC (premotor cortex) and Cer (cerebellum) in both stroke patients and healthy controls after the training. Findings of the present study suggest that enhancement of SMA activity could benefit M1 dysfunction in stroke survivors. These results also indicate that connectivity alterations between motor areas might assist the counterbalance of a functionally abnormal M1 in chronic stroke survivors and possibly other patients with motor dysfunction. PMID:23900349

  4. Visual cortex and auditory cortex activation in early binocularly blind macaques: A BOLD-fMRI study using auditory stimuli.

    Science.gov (United States)

    Wang, Rong; Wu, Lingjie; Tang, Zuohua; Sun, Xinghuai; Feng, Xiaoyuan; Tang, Weijun; Qian, Wen; Wang, Jie; Jin, Lixin; Zhong, Yufeng; Xiao, Zebin

    2017-04-15

    Cross-modal plasticity within the visual and auditory cortices of early binocularly blind macaques is not well studied. In this study, four healthy neonatal macaques were assigned to group A (control group) or group B (binocularly blind group). Sixteen months later, blood oxygenation level-dependent functional imaging (BOLD-fMRI) was conducted to examine the activation in the visual and auditory cortices of each macaque while being tested using pure tones as auditory stimuli. The changes in the BOLD response in the visual and auditory cortices of all macaques were compared with immunofluorescence staining findings. Compared with group A, greater BOLD activity was observed in the bilateral visual cortices of group B, and this effect was particularly obvious in the right visual cortex. In addition, more activated volumes were found in the bilateral auditory cortices of group B than of group A, especially in the right auditory cortex. These findings were consistent with the fact that there were more c-Fos-positive cells in the bilateral visual and auditory cortices of group B compared with group A (p visual cortices of binocularly blind macaques can be reorganized to process auditory stimuli after visual deprivation, and this effect is more obvious in the right than the left visual cortex. These results indicate the establishment of cross-modal plasticity within the visual and auditory cortices.

  5. Enhanced peripheral visual processing in congenitally deaf humans is supported by multiple brain regions, including primary auditory cortex.

    Science.gov (United States)

    Scott, Gregory D; Karns, Christina M; Dow, Mark W; Stevens, Courtney; Neville, Helen J

    2014-01-01

    Brain reorganization associated with altered sensory experience clarifies the critical role of neuroplasticity in development. An example is enhanced peripheral visual processing associated with congenital deafness, but the neural systems supporting this have not been fully characterized. A gap in our understanding of deafness-enhanced peripheral vision is the contribution of primary auditory cortex. Previous studies of auditory cortex that use anatomical normalization across participants were limited by inter-subject variability of Heschl's gyrus. In addition to reorganized auditory cortex (cross-modal plasticity), a second gap in our understanding is the contribution of altered modality-specific cortices (visual intramodal plasticity in this case), as well as supramodal and multisensory cortices, especially when target detection is required across contrasts. Here we address these gaps by comparing fMRI signal change for peripheral vs. perifoveal visual stimulation (11-15° vs. 2-7°) in congenitally deaf and hearing participants in a blocked experimental design with two analytical approaches: a Heschl's gyrus region of interest analysis and a whole brain analysis. Our results using individually-defined primary auditory cortex (Heschl's gyrus) indicate that fMRI signal change for more peripheral stimuli was greater than perifoveal in deaf but not in hearing participants. Whole-brain analyses revealed differences between deaf and hearing participants for peripheral vs. perifoveal visual processing in extrastriate visual cortex including primary auditory cortex, MT+/V5, superior-temporal auditory, and multisensory and/or supramodal regions, such as posterior parietal cortex (PPC), frontal eye fields, anterior cingulate, and supplementary eye fields. Overall, these data demonstrate the contribution of neuroplasticity in multiple systems including primary auditory cortex, supramodal, and multisensory regions, to altered visual processing in congenitally deaf adults.

  6. Enhanced peripheral visual processing in congenitally deaf humans is supported by multiple brain regions, including primary auditory cortex

    Directory of Open Access Journals (Sweden)

    Gregory D. Scott

    2014-03-01

    Full Text Available Brain reorganization associated with altered sensory experience clarifies the critical role of neuroplasticity in development. An example is enhanced peripheral visual processing associated with congenital deafness, but the neural systems supporting this have not been fully characterized. A gap in our understanding of deafness-enhanced peripheral vision is the contribution of primary auditory cortex. Previous studies of auditory cortex that use anatomical normalization across participants were limited by inter-subject variability of Heschl’s gyrus. In addition to reorganized auditory cortex (cross-modal plasticity, a second gap in our understanding is the contribution of altered modality-specific cortices (visual intramodal plasticity in this case, as well as supramodal and multisensory cortices, especially when target detection is required across contrasts. Here we address these gaps by comparing fMRI signal change for peripheral versus perifoveal visual stimulation (11-15° vs. 2°-7° in congenitally deaf and hearing participants in a blocked experimental design with two analytical approaches: a Heschl’s gyrus region of interest analysis and a whole brain analysis. Our results using individually-defined primary auditory cortex (Heschl’s gyrus indicate that fMRI signal change for more peripheral stimuli was greater than perifoveal in deaf but not in hearing participants. Whole-brain analyses revealed differences between deaf and hearing participants for peripheral versus perifoveal visual processing in extrastriate visual cortex including primary auditory cortex, MT+/V5, superior-temporal auditory and multisensory and/or supramodal regions, such as posterior parietal cortex, frontal eye fields, anterior cingulate, and supplementary eye fields. Overall, these data demonstrate the contribution of neuroplasticity in multiple systems including primary auditory cortex, supramodal and multisensory regions, to altered visual processing in

  7. Etude du cortex sensori-moteur en Imagerie par Résonance Magnétique Fonctionnelle : du sujet sain à l'enfant avec paralysie cérébrale

    OpenAIRE

    Dinomais, Mickael

    2013-01-01

    Cerebral palsy (CP) is a non-progressive injury to the developing central nervous system resulting in permanent disorders of the development of movement and posture, causing activity limitation. Therefore physical and rehabilitation medicine has a particular interest in the study of organization and reorganization of the sensorimotor cortex following early brain injury in order to propose new methods for motor rehabilitation. We first showed that motor cortex could be analyzed in functional m...

  8. Reorganizing Complex Network to Improve Large-Scale Multiagent Teamwork

    Directory of Open Access Journals (Sweden)

    Yang Xu

    2014-01-01

    Full Text Available Large-scale multiagent teamwork has been popular in various domains. Similar to human society infrastructure, agents only coordinate with some of the others, with a peer-to-peer complex network structure. Their organization has been proven as a key factor to influence their performance. To expedite team performance, we have analyzed that there are three key factors. First, complex network effects may be able to promote team performance. Second, coordination interactions coming from their sources are always trying to be routed to capable agents. Although they could be transferred across the network via different paths, their sources and sinks depend on the intrinsic nature of the team which is irrelevant to the network connections. In addition, the agents involved in the same plan often form a subteam and communicate with each other more frequently. Therefore, if the interactions between agents can be statistically recorded, we are able to set up an integrated network adjustment algorithm by combining the three key factors. Based on our abstracted teamwork simulations and the coordination statistics, we implemented the adaptive reorganization algorithm. The experimental results briefly support our design that the reorganized network is more capable of coordinating heterogeneous agents.

  9. Dynamic reorganization of brain functional networks during cognition.

    Science.gov (United States)

    Bola, Michał; Sabel, Bernhard A

    2015-07-01

    How does cognition emerge from neural dynamics? The dominant hypothesis states that interactions among distributed brain regions through phase synchronization give basis for cognitive processing. Such phase-synchronized networks are transient and dynamic, established on the timescale of milliseconds in order to perform specific cognitive operations. But unlike resting-state networks, the complex organization of transient cognitive networks is typically not characterized within the graph theory framework. Thus, it is not known whether cognitive processing merely changes the strength of functional connections or, conversely, requires qualitatively new topological arrangements of functional networks. To address this question, we recorded high-density EEG while subjects performed a visual discrimination task. We conducted an event-related network analysis (ERNA) where source-space weighted functional networks were characterized with graph measures. ERNA revealed rapid, transient, and frequency-specific reorganization of the network's topology during cognition. Specifically, cognitive networks were characterized by strong clustering, low modularity, and strong interactions between hub-nodes. Our findings suggest that dense and clustered connectivity between the hub nodes belonging to different modules is the "network fingerprint" of cognition. Such reorganization patterns might facilitate global integration of information and provide a substrate for a "global workspace" necessary for cognition and consciousness to occur. Thus, characterizing topology of the event-related networks opens new vistas to interpret cognitive dynamics in the broader conceptual framework of graph theory. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Reorganization of cytoskeletal proteins of mouse oocytes mediated by integrins

    Institute of Scientific and Technical Information of China (English)

    YUE Limin; ZHANG Lei; HE Yaping; ZHANG Jinhu; ZHENG Jie; HE Yanfang; ZHENG Yu; ZHANG Jie; ZHANG Li

    2004-01-01

    To study whether integrins on cell membrane ligate with intracellular cytoskeletal proteins and mediate their reorganization in egg activation, female mice were used for superovulation. The zona-free oocytes were incubated separately with specific ligand of integrins,an active RGD peptide, in vitro for certain period of time. RGE peptide and mouse capacitated sperm were used as controls. Freshly ovulated oocytes and those treated with different factors were immunostained with FITC-labeled anti-actin antibody, then detected with confocal microscope. The results demonstrated that freshly ovulated mouse oocytes, oocytes incubated for 2 h in vitro and those treated with control RGE peptide for 15 min showed hardly visible fluorescene or only thin fluorescence in plasma membrane region. Oocytes coincubated with sperms for 15 min and those treated with active RGD peptide for 10 min, 30 min and 2 hours respectively had strong and thick fluorescence in the plasma membrane and cortical region of oocytes, and some of them showed asymmetrically fluorescent distribution. It is proved that integrins on membrane are ligated directly with cytoskeletal protein. Integrins binding with their ligands regulate reorganization of cytoskelal protein, which may be involved in transmembrane signaling in egg activation.

  11. Reorganization of cytoskeletal proteins of mouse oocytes mediated by integrins

    Institute of Scientific and Technical Information of China (English)

    YUE; Limin; ZHANG; Lei; HE; Yaping; ZHANG; Jinhu; ZHENG; Ji

    2004-01-01

    To study whether integrins on cell membrane ligate with intracellular cytoskeletal proteins and mediate their reorganization in egg activation, female mice were used for superovulation. The zona-free oocytes were incubated separately with specific ligand of integrins,an active RGD peptide, in vitro for certain period of time. RGE peptide and mouse capacitated sperm were used as controls. Freshly ovulated oocytes and those treated with different factors were immunostained with FITC-labeled anti-actin antibody, then detected with confocal microscope. The results demonstrated that freshly ovulated mouse oocytes, oocytes incubated for 2 h in vitro and those treated with control RGE peptide for 15 min showed hardly visible fluorescene or only thin fluorescence in plasma membrane region. Oocytes coincubated with sperms for 15 min and those treated with active RGD peptide for 10 min, 30 min and 2 hours respectively had strong and thick fluorescence in the plasma membrane and cortical region of oocytes, and some of them showed asymmetrically fluorescent distribution. It is proved that integrins on membrane are ligated directly with cytoskeletal protein. Integrins binding with their ligands regulate reorganization of cytoskelal protein, which may be involved in transmembrane signaling in egg activation.

  12. Beta-globin LCR and intron elements cooperate and direct spatial reorganization for gene therapy.

    Directory of Open Access Journals (Sweden)

    Alla Buzina

    2008-04-01

    Full Text Available The Locus Control Region (LCR requires intronic elements within beta-globin transgenes to direct high level expression at all ectopic integration sites. However, these essential intronic elements cannot be transmitted through retrovirus vectors and their deletion may compromise the therapeutic potential for gene therapy. Here, we systematically regenerate functional beta-globin intron 2 elements that rescue LCR activity directed by 5'HS3. Evaluation in transgenic mice demonstrates that an Oct-1 binding site and an enhancer in the intron cooperate to increase expression levels from LCR globin transgenes. Replacement of the intronic AT-rich region with the Igmu 3'MAR rescues LCR activity in single copy transgenic mice. Importantly, a combination of the Oct-1 site, Igmu 3'MAR and intronic enhancer in the BGT158 cassette directs more consistent levels of expression in transgenic mice. By introducing intron-modified transgenes into the same genomic integration site in erythroid cells, we show that BGT158 has the greatest transcriptional induction. 3D DNA FISH establishes that induction stimulates this small 5'HS3 containing transgene and the endogenous locus to spatially reorganize towards more central locations in erythroid nuclei. Electron Spectroscopic Imaging (ESI of chromatin fibers demonstrates that ultrastructural heterochromatin is primarily perinuclear and does not reorganize. Finally, we transmit intron-modified globin transgenes through insulated self-inactivating (SIN lentivirus vectors into erythroid cells. We show efficient transfer and robust mRNA and protein expression by the BGT158 vector, and virus titer improvements mediated by the modified intron 2 in the presence of an LCR cassette composed of 5'HS2-4. Our results have important implications for the mechanism of LCR activity at ectopic integration sites. The modified transgenes are the first to transfer intronic elements that potentiate LCR activity and are designed to facilitate

  13. Evolutionary formation of gene clusters by reorganization: the meleagrin/roquefortine paradigm in different fungi.

    Science.gov (United States)

    Martín, Juan F; Liras, Paloma

    2016-02-01

    The biosynthesis of secondary metabolites in fungi is catalyzed by enzymes encoded by genes linked in clusters that are frequently co-regulated at the transcriptional level. Formation of gene clusters may take place by de novo assembly of genes recruited from other cellular functions, but also novel gene clusters are formed by reorganization of progenitor clusters and are distributed by horizontal gene transfer. This article reviews (i) the published information on the roquefortine/meleagrin/neoxaline gene clusters of Penicillium chrysogenum (Penicillium rubens) and the short roquefortine cluster of Penicillium roqueforti, and (ii) the correlation of the genes present in those clusters with the enzymes and metabolites derived from these pathways. The P. chrysogenum roq/mel cluster consists of seven genes and includes a gene (roqT) encoding a 12-TMS transporter protein of the MFS family. Interestingly, the orthologous P. roquefortine gene cluster has only four genes and the roqT gene is present as a residual pseudogene that encodes only small peptides. Two of the genes present in the central region of the P. chrysogenum roq/mel cluster have been lost during the evolutionary formation of the short cluster and the order of the structural genes in the cluster has been rearranged. The two lost genes encode a N1 atom hydroxylase (nox) and a roquefortine scaffold-reorganizing oxygenase (sro). As a consequence P. roqueforti has lost the ability to convert the roquefortine-type carbon skeleton to the glandicoline/meleagrin-type scaffold and is unable to produce glandicoline B, meleagrin and neoxaline. The loss of this genetic information is not recent and occurred probably millions of years ago when a progenitor Penicillium strain got adapted to life in a few rich habitats such as cheese, fermented cereal grains or silage. P. roqueforti may be considered as a "domesticated" variant of a progenitor common to contemporary P. chrysogenum and related Penicillia.

  14. Disconnection and hyper-connectivity underlie reorganization after TBI: A rodent functional connectomic analysis.

    Science.gov (United States)

    Harris, N G; Verley, D R; Gutman, B A; Thompson, P M; Yeh, H J; Brown, J A

    2016-03-01

    predicted by the structural deficits, not only within the primary sensorimotor injury site and pericontused regions, but the normally connected homotopic cortex, as well as subcortical regions, all of which persisted chronically. Especially novel in this study is the unanticipated finding of widespread increases in connection strength that dwarf both the degree and extent of the functional disconnections, and which persist chronically in some sensorimotor and subcortically connected regions. Exploratory global network analysis showed changes in network parameters indicative of possible acutely increased random connectivity and temporary reductions in modularity that were matched by local increases in connectedness and increased efficiency among more weakly connected regions. The global network parameters: shortest path-length, clustering coefficient and modularity that were most affected by trauma also scaled with the severity of injury, so that the corresponding regional measures were correlated to the injury severity most notably at 7 and 14 days and especially within, but not limited to, the contralateral cortex. These changes in functional network parameters are discussed in relation to the known time-course of physiologic and anatomic data that underlie structural and functional reorganization in this experiment model of TBI.

  15. The anterior cingulate cortex

    Directory of Open Access Journals (Sweden)

    Pavlović D.M.

    2009-01-01

    Full Text Available The anterior cingulate cortex (ACC has a role in attention, analysis of sensory information, error recognition, problem solving, detection of novelty, behavior, emotions, social relations, cognitive control, and regulation of visceral functions. This area is active whenever the individual feels some emotions, solves a problem, or analyzes the pros and cons of an action (if it is a right decision. Analogous areas are also found in higher mammals, especially whales, and they contain spindle neurons that enable complex social interactions. Disturbance of ACC activity is found in dementias, schizophrenia, depression, the obsessive-compulsive syndrome, and other neuropsychiatric diseases.

  16. Small-World Characteristics of Cortical Connectivity Changes in Acute Stroke.

    Science.gov (United States)

    Caliandro, Pietro; Vecchio, Fabrizio; Miraglia, Francesca; Reale, Giuseppe; Della Marca, Giacomo; La Torre, Giuseppe; Lacidogna, Giordano; Iacovelli, Chiara; Padua, Luca; Bramanti, Placido; Rossini, Paolo Maria

    2017-01-01

    Background After cerebral ischemia, disruption and subsequent reorganization of functional connections occur both locally and remote to the lesion. Recently, complexity of brain connectivity has been described using graph theory, a mathematical approach that depicts important properties of complex systems by quantifying topologies of network representations. Functional and dynamic changes of brain connectivity can be reliably analyzed via electroencephalography (EEG) recordings even when they are not yet reflected in structural changes of connections. Objective We tested whether and how ischemic stroke in the acute stage may determine changes in small-worldness of cortical networks as measured by cortical sources of EEG. Methods Graph characteristics of EEG of 30 consecutive stroke patients in acute stage (no more than 5 days after the event) were examined. Connectivity analysis was performed using eLORETA in both hemispheres. Results Network rearrangements were mainly detected in delta, theta, and alpha bands when patients were compared with healthy subjects. In delta and alpha bands similar findings were observed in both hemispheres regardless of the side of ischemic lesion: bilaterally decreased small-worldness in the delta band and bilaterally increased small-worldness in the alpha2 band. In the theta band, bilaterally decreased small-worldness was observed only in patients with stroke in the left hemisphere. Conclusions After an acute stroke, brain cortex rearranges its network connections diffusely, in a frequency-dependent modality probably in order to face the new anatomical and functional frame.

  17. Sensing with the Motor Cortex

    OpenAIRE

    Hatsopoulos, Nicholas G.; Suminski, Aaron J.

    2011-01-01

    The primary motor cortex is a critical node in the network of brain regions responsible for voluntary motor behavior. It has been less appreciated, however, that the motor cortex exhibits sensory responses in a variety of modalities including vision and somatosensation. We review current work that emphasizes the heterogeneity in sensori-motor responses in the motor cortex and focus on its implications for cortical control of movement as well as for brain-machine interface development.

  18. Motor recovery and cortical reorganization after mirror therapy in chronic stroke patients: a phase II randomized controlled trial.

    Science.gov (United States)

    Michielsen, Marian E; Selles, Ruud W; van der Geest, Jos N; Eckhardt, Martine; Yavuzer, Gunes; Stam, Henk J; Smits, Marion; Ribbers, Gerard M; Bussmann, Johannes B J

    2011-01-01

    To evaluate for any clinical effects of home-based mirror therapy and subsequent cortical reorganization in patients with chronic stroke with moderate upper extremity paresis. A total of 40 chronic stroke patients (mean time post .onset, 3.9 years) were randomly assigned to the mirror group (n = 20) or the control group (n = 20) and then joined a 6-week training program. Both groups trained once a week under supervision of a physiotherapist at the rehabilitation center and practiced at home 1 hour daily, 5 times a week. The primary outcome measure was the Fugl-Meyer motor assessment (FMA). The grip force, spasticity, pain, dexterity, hand-use in daily life, and quality of life at baseline-posttreatment and at 6 months-were all measured by a blinded assessor. Changes in neural activation patterns were assessed with functional magnetic resonance imaging (fMRI) at baseline and posttreatment in an available subgroup (mirror, 12; control, 9). Posttreatment, the FMA improved more in the mirror than in the control group (3.6 ± 1.5, P .05). fMRI results showed a shift in activation balance within the primary motor cortex toward the affected hemisphere in the mirror group only (weighted laterality index difference 0.40 ± 0.39, P mirror therapy in chronic stroke patients and is the first to associate mirror therapy with cortical reorganization. Future research has to determine the optimum practice intensity and duration for improvements to persist and generalize to other functional domains.

  19. Cone inputs to murine striate cortex

    Directory of Open Access Journals (Sweden)

    Gouras Peter

    2008-11-01

    Full Text Available Abstract Background We have recorded responses from single neurons in murine visual cortex to determine the effectiveness of the input from the two murine cone photoreceptor mechanisms and whether there is any unique selectivity for cone inputs at this higher region of the visual system that would support the possibility of colour vision in mice. Each eye was stimulated by diffuse light, either 370 (strong stimulus for the ultra-violet (UV cone opsin or 505 nm (exclusively stimulating the middle wavelength sensitive (M cone opsin, obtained from light emitting diodes (LEDs in the presence of a strong adapting light that suppressed the responses of rods. Results Single cells responded to these diffuse stimuli in all areas of striate cortex. Two types of responsive cells were encountered. One type (135/323 – 42% had little to no spontaneous activity and responded at either the on and/or the off phase of the light stimulus with a few impulses often of relatively large amplitude. A second type (166/323 – 51% had spontaneous activity and responded tonically to light stimuli with impulses often of small amplitude. Most of the cells responded similarly to both spectral stimuli. A few (18/323 – 6% responded strongly or exclusively to one or the other spectral stimulus and rarely in a spectrally opponent manner. Conclusion Most cells in murine striate cortex receive excitatory inputs from both UV- and M-cones. A small fraction shows either strong selectivity for one or the other cone mechanism and occasionally cone opponent responses. Cells that could underlie chromatic contrast detection are present but extremely rare in murine striate cortex.

  20. 29 CFR Appendix A to Part 24 - Your Rights Under the Energy Reorganization Act

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 1 2010-07-01 2010-07-01 true Your Rights Under the Energy Reorganization Act A Appendix A to Part 24 Labor Office of the Secretary of Labor PROCEDURES FOR THE HANDLING OF RETALIATION... the Energy Reorganization Act ER10AU07.000...

  1. 76 FR 86 - Expansion/Reorganization of Foreign-Trade Zone 202, Los Angeles, CA

    Science.gov (United States)

    2011-01-03

    ... Foreign-Trade Zones Board Expansion/Reorganization of Foreign-Trade Zone 202, Los Angeles, CA Pursuant to... Commissioners of the City of Los Angeles, grantee of Foreign-Trade Zone 202, submitted an application to the Board for authority to reorganize and expand FTZ 202 in the Los Angeles, California area, within...

  2. Relationship between chronic pain and brain reorganization after deafferentation: A systematic review of functional MRI findings

    Directory of Open Access Journals (Sweden)

    C.R. Jutzeler

    2015-01-01

    Conclusion: Based solely on advanced functional neuroimaging results, there is only limited evidence for a relationship between chronic pain intensity and reorganization after deafferentation. The review demonstrates the need for additional neuroimaging studies to clarify the relationship between chronic pain and reorganization.

  3. Protein degradation during reconsolidation as a mechanism for memory reorganization

    Directory of Open Access Journals (Sweden)

    Bong-Kiun Kaang

    2011-02-01

    Full Text Available Memory is a reference formed from a past experience that is used to respond to present situations. However, the world is dynamic and situations change, so it is important to update the memory with new information each time it is reactivated in order to adjust the response in the future. Recent researches indicate that memory may undergo a dynamic process that could work as an updating mechanism. This process which is called reconsolidation involves destabilization of the memory after it is reactivated, followed by restabilization. Recently, it has been demonstrated that the initial destabilization process of reconsolidation requires protein degradation. Using protein degradation inhibition as a method to block reconsolidation, recent researches suggest that reconsolidation, especially the protein degradation-dependent destabilization process is necessary for memory reorganization.

  4. Cultural differences in perceptual reorganization in US and Piraha adults.

    Directory of Open Access Journals (Sweden)

    Jennifer M D Yoon

    Full Text Available Visual illusions and other perceptual phenomena can be used as tools to uncover the otherwise hidden constructive processes that give rise to perception. Although many perceptual processes are assumed to be universal, variable susceptibility to certain illusions and perceptual effects across populations suggests a role for factors that vary culturally. One striking phenomenon is seen with two-tone images-photos reduced to two tones: black and white. Deficient recognition is observed in young children under conditions that trigger automatic recognition in adults. Here we show a similar lack of cue-triggered perceptual reorganization in the Pirahã, a hunter-gatherer tribe with limited exposure to modern visual media, suggesting such recognition is experience- and culture-specific.

  5. Glassy protein dynamics and gigantic solvent reorganization energy of plastocyanin

    CERN Document Server

    LeBard, David N

    2007-01-01

    We report the results of Molecular Dynamics simulations of electron transfer activation parameters of plastocyanin metalloprotein involved as electron carrier in natural photosynthesis. We have discovered that slow, non-ergodic conformational fluctuations of the protein, coupled to hydrating water, result in a very broad distribution of donor-acceptor energy gaps far exceeding that observed for commonly studied inorganic and organic donor-acceptor complexes. The Stokes shift is not affected by these fluctuations and can be calculated from solvation models in terms of the response of the solvent dipolar polarization. The non-ergodic character of large-amplitude protein/water mobility breaks the strong link between the Stokes shift and reorganization energy characteristic of equilibrium (ergodic) theories of electron transfer. This mechanism might be responsible for low activation barriers in natural electron transfer proteins characterized by low reaction free energy.

  6. Analysis of Septin Reorganization at Cytokinesis Using Polarized Fluorescence Microscopy

    Directory of Open Access Journals (Sweden)

    Molly McQuilken

    2017-05-01

    Full Text Available Septins are conserved filament-forming proteins that act in diverse cellular processes. They closely associate with membranes and, in some systems, components of the cytoskeleton. It is not well understood how filaments assemble into higher-order structures in vivo or how they are remodeled throughout the cell cycle. In the budding yeast S. cerevisiae, septins are found through most of the cell cycle in an hourglass organization at the mother-bud neck until cytokinesis when the collar splits into two rings that disassemble prior to the next cell cycle. Experiments using polarized fluorescence microscopy have suggested that septins are arranged in ordered, paired filaments in the hourglass and undergo a coordinated 90° reorientation during splitting at cytokinesis. This apparent reorganization could be due to two orthogonal populations of filaments disassembling and reassembling or being preferentially retained at cytokinesis. In support of this idea, we report a decrease in septin concentration at the mother-bud neck during cytokinesis consistent with other reports and the timing of the decrease depends on known septin regulators including the Gin4 kinase. We took a candidate-based approach to examine what factors control reorientation during splitting and used polarized fluorescence microscopy to screen mutant yeast strains deficient in septin interacting proteins. Using this method, we have linked known septin regulators to different aspects of the assembly, stability, and reorganization of septin assemblies. The data support that ring splitting requires Gin4 activity and an anillin-like protein Bud4, and normal accumulation of septins at the ring requires phosphorylation of Shs1. We found distinct regulatory requirements for septin organization in the hourglass compared to split rings. We propose that septin subpopulations can vary in their localization and assembly/disassembly behavior in a cell-cycle dependent manner at cytokinesis.

  7. A gauge-invariant reorganization of thermal gauge theory

    Energy Technology Data Exchange (ETDEWEB)

    Su, Nan

    2010-07-01

    This dissertation is devoted to the study of thermodynamics for quantum gauge theories. The poor convergence of quantum field theory at finite temperature has been the main obstacle in the practical applications of thermal QCD for decades. In this dissertation I apply hard-thermal-loop perturbation theory, which is a gauge-invariant reorganization of the conventional perturbative expansion for quantum gauge theories to the thermodynamics of QED and Yang-Mills theory to three-loop order. For the Abelian case, I present a calculation of the free energy of a hot gas of electrons and photons by expanding in a power series in m{sub D}/T, m{sub f}/T and e{sup 2}, where m{sub D} and m{sub f} are the photon and electron thermal masses, respectively, and e is the coupling constant. I demonstrate that the hard-thermal-loop perturbation reorganization improves the convergence of the successive approximations to the QED free energy at large coupling, e {proportional_to} 2. For the non-Abelian case, I present a calculation of the free energy of a hot gas of gluons by expanding in a power series in m{sub D}/T and g{sup 2}, where m{sub D} is the gluon thermal mass and g is the coupling constant. I show that at three-loop order hard-thermal-loop perturbation theory is compatible with lattice results for the pressure, energy density, and entropy down to temperatures T {proportional_to} 2 - 3 T{sub c}. The results suggest that HTLpt provides a systematic framework that can be used to calculate static and dynamic quantities for temperatures relevant at LHC. (orig.)

  8. Reorganization characteristics of speech cortex during speech restoration following total laryngectomy A functional magnetic resonance imaging follow-up

    Institute of Scientific and Technical Information of China (English)

    Jianzhong Yin; Yonggang Xue; Peng Lin; Xuchu Weng; Ji Qi

    2011-01-01

    During speech restoration following laryngectomy, language-related cortical areas develop connections with new primary motor neurons. The present study followed up 18 patients after total resection of laryngeal carcinoma. According to an evaluation of pronunciation, patients were assigned to three groups: poor, moderate and good pronunciation. Functional magnetic resonance imaging revealed significant increases in the number of activated voxels and the intensity of activation changes in the left middle frontal gyrus, left precentral gyrus, left postcentral gyrus, left supplementary motor area, left anterior cingulate gyrus and right fusiform gyrus between the moderate pronunciation group compared with the poor and good pronunciation groups. We propose that these brain regions play an important role in the progress of speech restoration, and improvements in pronunciation learning for patients following laryngectomy. However, during the later period of speech restoration, the number of activated voxels and intensity changes in these regions decreased to the level of healthy controls, indicating that the learning and instruction effects weakened once patients had mastered pronunciation techniques.

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

    DEFF Research Database (Denmark)

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

    retains a residual M1-c activity when amputees perform phantom limb movements (4-5). Except a correlation between phantom limb pain and M1-c expansion of the face (2-3), the relationship between the ability to voluntary move the phantom hand, the level of phantom limb pain, the degree of M1-c......Amputation of a limb induces reorganization within the contralateral primary motor cortex (M1-c) (1-3). In the case of hand amputation, M1-c areas evoking movements in the face and the remaining part of the upper-limb expand toward the hand area. Despite this expansion, the amputated hand still...

  10. The spatiotopic 'visual' cortex of the blind

    Science.gov (United States)

    Likova, Lora

    2012-03-01

    Visual cortex activity in the blind has been shown in sensory tasks. Can it be activated in memory tasks? If so, are inherent features of its organization meaningfully employed? Our recent results in short-term blindfolded subjects imply that human primary visual cortex (V1) may operate as a modality-independent 'sketchpad' for working memory (Likova, 2010a). Interestingly, the spread of the V1 activation approximately corresponded to the spatial extent of the images in terms of their angle of projection to the subject. We now raise the questions of whether under long-term visual deprivation V1 is also employed in non-visual memory task, in particular in congenitally blind individuals, who have never had visual stimulation to guide the development of the visual area organization, and whether such spatial organization is still valid for the same paradigm that was used in blindfolded individuals. The outcome has implications for an emerging reconceptualization of the principles of brain architecture and its reorganization under sensory deprivation. Methods: We used a novel fMRI drawing paradigm in congenitally and late-onset blind, compared with sighted and blindfolded subjects in three conditions of 20s duration, separated by 20s rest-intervals, (i) Tactile Exploration: raised-line images explored and memorized; (ii) Tactile Memory Drawing: drawing the explored image from memory; (iii) Scribble: mindless drawing movements with no memory component. Results and Conclusions: V1 was strongly activated for Tactile Memory Drawing and Tactile Exploration in these totally blind subjects. Remarkably, after training, even in the memory task, the mapping of V1 activation largely corresponded to the angular projection of the tactile stimuli relative to the ego-center (i.e., the effective visual angle at the head); beyond this projective boundary, peripheral V1 signals were dramatically reduced or even suppressed. The matching extent of the activation in the congenitally blind

  11. Word Recognition in Auditory Cortex

    Science.gov (United States)

    DeWitt, Iain D. J.

    2013-01-01

    Although spoken word recognition is more fundamental to human communication than text recognition, knowledge of word-processing in auditory cortex is comparatively impoverished. This dissertation synthesizes current models of auditory cortex, models of cortical pattern recognition, models of single-word reading, results in phonetics and results in…

  12. Red light, Phot1 and JAC1 modulate Phot2-dependent reorganization of chloroplast actin filaments and chloroplast avoidance movement.

    Science.gov (United States)

    Ichikawa, Satoshi; Yamada, Noboru; Suetsugu, Noriyuki; Wada, Masamitsu; Kadota, Akeo

    2011-08-01

    The phototropin (phot)-dependent intracellular relocation of chloroplasts is a ubiquitous phenomenon in plants. We have previously revealed the involvement of a short cp-actin (chloroplast actin) filament-based mechanism in this movement. Here, the reorganization of cp-actin filaments during the avoidance movement of chloroplasts was analyzed in higher time resolution under blue GFP (green fluorescent protein) excitation light in an actin filament-visualized line of Arabidopsis thaliana. Under standard background red light of 89 μmol m(-2) s(-1), cp-actin filaments transiently disappeared at approximately 30 s and reappeared in a biased configuration on chloroplasts approximately 70 s after blue excitation light irradiation. The timing of biased cp-actin reappearance was delayed under the background of strong red light or in the absence of red light. Consistently, chloroplast movement was delayed under these conditions. In phot1 mutants, acceleration of both the disappearance and reappearance of cp-actin filaments occurred, indicating an inhibitory action of phot1 on reorganization of cp-actin filaments. Avoidance movements began sooner in phot1 than in wild-type plants. No reorganization of cp-actin filaments was seen in phot2 or phot1phot2 mutants lacking phot2, which is responsible for avoidance movements. Surprisingly, jac1 (j-domain protein required for chloroplast accumulation response 1) mutants, lacking the accumulation response, showed no avoidance movements under the whole-cell irradiation condition for GFP observation. Cp-actin filaments in jac1 did not show a biased distribution, with a small or almost no transient decrease in the number. These results indicate a close association between the biased distribution of cp-actin filaments and chloroplast movement. Further, JAC1 is suggested to function in the biased cp-actin filament distribution by regulating their appearance and disappearance.

  13. Cochlear injury and adaptive plasticity of the auditory cortex

    Directory of Open Access Journals (Sweden)

    ANNA R. eFETONI

    2015-02-01

    Full Text Available Growing evidence suggests that cochlear stressors as noise exposure and aging can induce homeostatic/maladaptive changes in the central auditory system from the brainstem to the cortex. Studies centered on such changes have revealed several mechanisms that operate in the context of sensory disruption after insult (noise trauma, drug- or age-related injury. The oxidative stress is central to current theories of induced sensory neural hearing loss and aging, and interventions to attenuate the hearing loss are based on antioxidant agent. The present review addresses the recent literature on the alterations in hair cells and spiral ganglion neurons due to noise-induced oxidative stress in the cochlea, as well on the impact of cochlear damage on the auditory cortex neurons. The emerging image emphasizes that noise-induced deafferentation and upward spread of cochlear damage is associated with the altered dendritic architecture of auditory pyramidal neurons. The cortical modifications may be reversed by treatment with antioxidants counteracting the cochlear redox imbalance. These findings open new therapeutic approaches to treat the functional consequences of the cortical reorganization following cochlear damage.

  14. Background sounds contribute to spectrotemporal plasticity in primary auditory cortex.

    Science.gov (United States)

    Moucha, Raluca; Pandya, Pritesh K; Engineer, Navzer D; Rathbun, Daniel L; Kilgard, Michael P

    2005-05-01

    The mammalian auditory system evolved to extract meaningful information from complex acoustic environments. Spectrotemporal selectivity of auditory neurons provides a potential mechanism to represent natural sounds. Experience-dependent plasticity mechanisms can remodel the spectrotemporal selectivity of neurons in primary auditory cortex (A1). Electrical stimulation of the cholinergic nucleus basalis (NB) enables plasticity in A1 that parallels natural learning and is specific to acoustic features associated with NB activity. In this study, we used NB stimulation to explore how cortical networks reorganize after experience with frequency-modulated (FM) sweeps, and how background stimuli contribute to spectrotemporal plasticity in rat auditory cortex. Pairing an 8-4 kHz FM sweep with NB stimulation 300 times per day for 20 days decreased tone thresholds, frequency selectivity, and response latency of A1 neurons in the region of the tonotopic map activated by the sound. In an attempt to modify neuronal response properties across all of A1 the same NB activation was paired in a second group of rats with five downward FM sweeps, each spanning a different octave. No changes in FM selectivity or receptive field (RF) structure were observed when the neural activation was distributed across the cortical surface. However, the addition of unpaired background sweeps of different rates or direction was sufficient to alter RF characteristics across the tonotopic map in a third group of rats. These results extend earlier observations that cortical neurons can develop stimulus specific plasticity and indicate that background conditions can strongly influence cortical plasticity.

  15. Egocentric and allocentric representations in auditory cortex.

    Science.gov (United States)

    Town, Stephen M; Brimijoin, W Owen; Bizley, Jennifer K

    2017-06-01

    A key function of the brain is to provide a stable representation of an object's location in the world. In hearing, sound azimuth and elevation are encoded by neurons throughout the auditory system, and auditory cortex is necessary for sound localization. However, the coordinate frame in which neurons represent sound space remains undefined: classical spatial receptive fields in head-fixed subjects can be explained either by sensitivity to sound source location relative to the head (egocentric) or relative to the world (allocentric encoding). This coordinate frame ambiguity can be resolved by studying freely moving subjects; here we recorded spatial receptive fields in the auditory cortex of freely moving ferrets. We found that most spatially tuned neurons represented sound source location relative to the head across changes in head position and direction. In addition, we also recorded a small number of neurons in which sound location was represented in a world-centered coordinate frame. We used measurements of spatial tuning across changes in head position and direction to explore the influence of sound source distance and speed of head movement on auditory cortical activity and spatial tuning. Modulation depth of spatial tuning increased with distance for egocentric but not allocentric units, whereas, for both populations, modulation was stronger at faster movement speeds. Our findings suggest that early auditory cortex primarily represents sound source location relative to ourselves but that a minority of cells can represent sound location in the world independent of our own position.

  16. Entorhinal cortex and consolidated memory.

    Science.gov (United States)

    Takehara-Nishiuchi, Kaori

    2014-07-01

    The entorhinal cortex is thought to support rapid encoding of new associations by serving as an interface between the hippocampus and neocortical regions. Although the entorhinal-hippocampal interaction is undoubtedly essential for initial memory acquisition, the entorhinal cortex contributes to memory retrieval even after the hippocampus is no longer necessary. This suggests that during memory consolidation additional synaptic reinforcement may take place within the cortical network, which may change the connectivity of entorhinal cortex with cortical regions other than the hippocampus. Here, I outline behavioral and physiological findings which collectively suggest that memory consolidation involves the gradual strengthening of connection between the entorhinal cortex and the medial prefrontal/anterior cingulate cortex (mPFC/ACC), a region that may permanently store the learned association. This newly formed connection allows for close interaction between the entorhinal cortex and the mPFC/ACC, through which the mPFC/ACC gains access to neocortical regions that store the content of memory. Thus, the entorhinal cortex may serve as a gatekeeper of cortical memory network by selectively interacting either with the hippocampus or mPFC/ACC depending on the age of memory. This model provides a new framework for a modification of cortical memory network during systems consolidation, thereby adding a fresh dimension to future studies on its biological mechanism.

  17. Cerebral cortex modulation of pain

    Institute of Scientific and Technical Information of China (English)

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

    2009-01-01

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

  18. Porous silicon reorganization: Influence on the structure, surface roughness and strain

    Science.gov (United States)

    Milenkovic, N.; Drießen, M.; Weiss, C.; Janz, S.

    2015-12-01

    Porous silicon and epitaxial thickening is a lift-off approach for silicon foil fabrication to avoid kerf losses and produce foils with thicknesses less than 50 μm. The crystal quality of the epitaxial silicon film strongly depends on the porous silicon template, which can be adapted through a reorganization process prior to epitaxy. In this work, we investigated the influence of reorganization on the structure of etched porous silicon layers. The reorganization processes were carried out in a quasi-inline Atmospheric Pressure Chemical Vapor Deposition reactor. Variations on the temperatures and process durations for the reorganization step were examined. The cross-sections showed that porous silicon requires temperatures of approximately 1150 °C to produce an excellent template for epitaxy. Atomic Force Microscopy measurements on the samples annealed at different temperatures showed the evolution of the pores from as-etched to a closed surface. These measurements confirm that the surface is not yet closed after 30 min of reorganization at 1000 °C. Different durations of the reorganization step at a fixed temperature of 1150 °C all lead to a closed surface with a comparable roughness of less than 0.5 nm. X-ray diffraction measurements show a change in the strain in the porous layer from tensile to compressive when the reorganization temperature is increased from 800 °C to 1150 °C. A longer reorganization at a fixed temperature of 1150 °C leads to a reduction in the strain without reducing the quality of the surface roughness. Defect density measurements on silicon layers deposited on those templates confirm an improvement of the template for longer reorganization times. This study shows that our porous silicon templates achieve lower surface roughness and strain values than those reported in other publications.

  19. Small GTPase Rab21 mediates fibronectin induced actin reorganization in Entamoeba histolytica: implications in pathogen invasion.

    Directory of Open Access Journals (Sweden)

    Merlyn Emmanuel

    2015-03-01

    Full Text Available The protozoan parasite Entamoeba histolytica causes a wide spectrum of intestinal infections. In severe cases, the trophozoites can breach the mucosal barrier, invade the intestinal epithelium and travel via the portal circulation to the liver, where they cause hepatic abscesses, which can prove fatal if left untreated. The host Extra Cellular Matrix (ECM plays a crucial role in amoebic invasion by triggering an array of cellular responses in the parasite, including induction of actin rich adhesion structures. Similar actin rich protrusive structures, known as 'invadosomes', promote chemotactic migration of the metastatic cancer cells and non-transformed cells by remodeling the ECM. Recent studies showed a central role for Rab GTPases, the master regulators of vesicular trafficking, in biogenesis of invadosomes. Here, we showed that fibronectin, a major host ECM component induced actin remodeling in the parasite in a Rab21 dependent manner. The focalized actin structures formed were reminiscent of the mammalian invadosomes. By using various approaches, such as immunofluorescence confocal microscopy and scanning electron microscopy, along with in vitro invasion assay and matrix degradation assay, we show that the fibronectin induced formation of amoebic actin dots depend on the nucleotide status of the GTPase. The ECM components, fibronectin and collagen type I, displayed differential control over the formation of actin dots, with fibronectin positively and collagen type I negatively modulating it. The cell surface adhesion molecule Gal/GalNAc complex was also found to impose additional regulation on this process, which might have implication in collagen type I mediated suppression of actin dots.

  20. Small GTPase Rab21 Mediates Fibronectin Induced Actin Reorganization in Entamoeba histolytica: Implications in Pathogen Invasion

    Science.gov (United States)

    Emmanuel, Merlyn; Nakano, Yumiko Saito; Nozaki, Tomoyoshi; Datta, Sunando

    2015-01-01

    The protozoan parasite Entamoeba histolytica causes a wide spectrum of intestinal infections. In severe cases, the trophozoites can breach the mucosal barrier, invade the intestinal epithelium and travel via the portal circulation to the liver, where they cause hepatic abscesses, which can prove fatal if left untreated. The host Extra Cellular Matrix (ECM) plays a crucial role in amoebic invasion by triggering an array of cellular responses in the parasite, including induction of actin rich adhesion structures. Similar actin rich protrusive structures, known as ‘invadosomes’, promote chemotactic migration of the metastatic cancer cells and non-transformed cells by remodeling the ECM. Recent studies showed a central role for Rab GTPases, the master regulators of vesicular trafficking, in biogenesis of invadosomes. Here, we showed that fibronectin, a major host ECM component induced actin remodeling in the parasite in a Rab21 dependent manner. The focalized actin structures formed were reminiscent of the mammalian invadosomes. By using various approaches, such as immunofluorescence confocal microscopy and scanning electron microscopy, along with in vitro invasion assay and matrix degradation assay, we show that the fibronectin induced formation of amoebic actin dots depend on the nucleotide status of the GTPase. The ECM components, fibronectin and collagen type I, displayed differential control over the formation of actin dots, with fibronectin positively and collagen type I negatively modulating it. The cell surface adhesion molecule Gal/GalNAc complex was also found to impose additional regulation on this process, which might have implication in collagen type I mediated suppression of actin dots. PMID:25730114

  1. Sharp wave-associated synchronized inputs from the piriform cortex activate olfactory tubercle neurons during slow-wave sleep.

    Science.gov (United States)

    Narikiyo, Kimiya; Manabe, Hiroyuki; Mori, Kensaku

    2014-01-01

    During slow-wave sleep, anterior piriform cortex neurons show highly synchronized discharges that accompany olfactory cortex sharp waves (OC-SPWs). The OC-SPW-related synchronized activity of anterior piriform cortex neurons travel down to the olfactory bulb and is thought to be involved in the reorganization of bulbar neuronal circuitry. However, influences of the OC-SPW-related activity on other regions of the central olfactory system are still unknown. Olfactory tubercle is an area of OC and part of ventral striatum that plays a key role in reward-directed motivational behaviors. In this study, we show that in freely behaving rats, olfactory tubercle receives OC-SPW-associated synchronized inputs during slow-wave sleep. Local field potentials in the olfactory tubercle showed SPW-like activities that were in synchrony with OC-SPWs. Single-unit recordings showed that a subpopulation of olfactory tubercle neurons discharged in synchrony with OC-SPWs. Furthermore, correlation analysis of spike activity of anterior piriform cortex and olfactory tubercle neurons revealed that the discharges of anterior piriform cortex neurons tended to precede those of olfactory tubercle neurons. Current source density analysis in urethane-anesthetized rats indicated that the current sink of the OC-SPW-associated input was located in layer III of the olfactory tubercle. These results indicate that OC-SPW-associated synchronized discharges of piriform cortex neurons travel to the deep layer of the olfactory tubercle and drive discharges of olfactory tubercle neurons. The entrainment of olfactory tubercle neurons in the OC-SPWs suggests that OC-SPWs coordinate reorganization of neuronal circuitry across wide areas of the central olfactory system including olfactory tubercle during slow-wave sleep.

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

    Directory of Open Access Journals (Sweden)

    Jill B Firszt

    2013-12-01

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

  3. Brain network reorganization differs in response to stress in rats genetically predisposed to depression and stress-resilient rats.

    Science.gov (United States)

    Gass, N; Becker, R; Schwarz, A J; Weber-Fahr, W; Clemm von Hohenberg, C; Vollmayr, B; Sartorius, A

    2016-12-06

    Treatment-resistant depression (TRD) remains a pressing clinical problem. Optimizing treatment requires better definition of the specificity of the involved brain circuits. The rat strain bred for negative cognitive state (NC) represents a genetic animal model of TRD with high face, construct and predictive validity. Vice versa, the positive cognitive state (PC) strain represents a stress-resilient phenotype. Although NC rats show depressive-like behavior, some symptoms such as anhedonia require an external trigger, i.e. a stressful event, which is similar to humans when stressful event induces a depressive episode in genetically predisposed individuals (gene-environment interaction). We aimed to distinguish neurobiological predisposition from the depressogenic pathology at the level of brain-network reorganization. For this purpose, resting-state functional magnetic resonance imaging time series were acquired at 9.4 Tesla scanner in NC (N=11) and PC (N=7) rats before and after stressful event. We used a graph theory analytical approach to calculate the brain-network global and local properties. There was no difference in the global characteristics between the strains. At the local level, the response in the risk strain was characterized with an increased internodal role and reduced local clustering and efficiency of the anterior cingulate cortex (ACC) and prelimbic cortex compared to the stress-resilient strain. We suggest that the increased internodal role of these prefrontal regions could be due to the enhancement of some of their long-range connections, given their connectivity with the amygdala and other default-mode-like network hubs, which could create a bias to attend to negative information characteristic for depression.

  4. Enhancing Physical Activity and Brain Reorganization after Stroke

    Directory of Open Access Journals (Sweden)

    Janet H. Carr

    2011-01-01

    Full Text Available It is becoming increasingly clear that, if reorganization of brain function is to be optimal after stroke, there needs to be a reorganisation of the methods used in physical rehabilitation and the time spent in specific task practice, strength and endurance training, and aerobic exercise. Frequency and intensity of rehabilitation need to be increased so that patients can gain the energy levels and vigour necessary for participation in physical activity both during rehabilitation and after discharge. It is evident that many patients are discharged from inpatient rehabilitation severely deconditioned, meaning that their energy levels are too low for active participation in daily life. Physicians, therapists, and nursing staff responsible for rehabilitation practice should address this issue not only during inpatient rehabilitation but also after discharge by promoting and supporting community-based exercise opportunities. During inpatient rehabilitation, group sessions should be frequent and need to include specific aerobic training. Physiotherapy must take advantage of the training aids available, including exercise equipment such as treadmills, and of new developments in computerised feedback systems, robotics, and electromechanical trainers. For illustrative purposes, this paper focuses on the role of physiotherapists, but the necessary changes in practice and in attitude will require cooperation from many others.

  5. Hippocampal-neocortical functional reorganization underlies children's cognitive development.

    Science.gov (United States)

    Qin, Shaozheng; Cho, Soohyun; Chen, Tianwen; Rosenberg-Lee, Miriam; Geary, David C; Menon, Vinod

    2014-09-01

    The importance of the hippocampal system for rapid learning and memory is well recognized, but its contributions to a cardinal feature of children's cognitive development-the transition from procedure-based to memory-based problem-solving strategies-are unknown. Here we show that the hippocampal system is pivotal to this strategic transition. Longitudinal functional magnetic resonance imaging (fMRI) in 7-9-year-old children revealed that the transition from use of counting to memory-based retrieval parallels increased hippocampal and decreased prefrontal-parietal engagement during arithmetic problem solving. Longitudinal improvements in retrieval-strategy use were predicted by increased hippocampal-neocortical functional connectivity. Beyond childhood, retrieval-strategy use continued to improve through adolescence into adulthood and was associated with decreased activation but more stable interproblem representations in the hippocampus. Our findings provide insights into the dynamic role of the hippocampus in the maturation of memory-based problem solving and establish a critical link between hippocampal-neocortical reorganization and children's cognitive development.

  6. Membrane indentation triggers clathrin lattice reorganization and fluidization.

    Science.gov (United States)

    Cordella, Nicholas; Lampo, Thomas J; Melosh, Nicholas; Spakowitz, Andrew J

    2015-01-21

    Clathrin-mediated endocytosis involves the coordinated assembly of clathrin cages around membrane indentations, necessitating fluid-like reorganization followed by solid-like stabilization. This apparent duality in clathrin's in vivo behavior provides some indication that the physical interactions between clathrin triskelia and the membrane effect a local response that triggers fluid-solid transformations within the clathrin lattice. We develop a computational model to study the response of clathrin protein lattices to spherical deformations of the underlying flexible membrane. These deformations are similar to the shapes assumed during intracellular trafficking of nanoparticles. Through Monte Carlo simulations of clathrin-on-membrane systems, we observe that these membrane indentations give rise to a greater than normal defect density within the overlaid clathrin lattice. In many cases, the bulk surrounding lattice remains in a crystalline phase, and the extra defects are localized to the regions of large curvature. This can be explained by the fact that the in-plane elastic stress in the clathrin lattice are reduced by coupling defects to highly curved regions. The presence of defects brought about by indentation can result in the fluidization of a lattice that would otherwise be crystalline, resulting in an indentation-driven, defect-mediated phase transition. Altering subunit elasticity or membrane properties is shown to drive a similar transition, and we present phase diagrams that map out the combined effects of these parameters on clathrin lattice properties.

  7. Global Reorganization of the Nuclear Landscape in Senescent Cells

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    Tamir Chandra

    2015-02-01

    Full Text Available Cellular senescence has been implicated in tumor suppression, development, and aging and is accompanied by large-scale chromatin rearrangements, forming senescence-associated heterochromatic foci (SAHF. However, how the chromatin is reorganized during SAHF formation is poorly understood. Furthermore, heterochromatin formation in senescence appears to contrast with loss of heterochromatin in Hutchinson-Gilford progeria. We mapped architectural changes in genome organization in cellular senescence using Hi-C. Unexpectedly, we find a dramatic sequence- and lamin-dependent loss of local interactions in heterochromatin. This change in local connectivity resolves the paradox of opposing chromatin changes in senescence and progeria. In addition, we observe a senescence-specific spatial clustering of heterochromatic regions, suggesting a unique second step required for SAHF formation. Comparison of embryonic stem cells (ESCs, somatic cells, and senescent cells shows a unidirectional loss in local chromatin connectivity, suggesting that senescence is an endpoint of the continuous nuclear remodelling process during differentiation.

  8. Mechanism of filopodia initiation by reorganization of a dendritic network.

    Science.gov (United States)

    Svitkina, Tatyana M; Bulanova, Elena A; Chaga, Oleg Y; Vignjevic, Danijela M; Kojima, Shin-ichiro; Vasiliev, Jury M; Borisy, Gary G

    2003-02-03

    Afilopodium protrudes by elongation of bundled actin filaments in its core. However, the mechanism of filopodia initiation remains unknown. Using live-cell imaging with GFP-tagged proteins and correlative electron microscopy, we performed a kinetic-structural analysis of filopodial initiation in B16F1 melanoma cells. Filopodial bundles arose not by a specific nucleation event, but by reorganization of the lamellipodial dendritic network analogous to fusion of established filopodia but occurring at the level of individual filaments. Subsets of independently nucleated lamellipodial filaments elongated and gradually associated with each other at their barbed ends, leading to formation of cone-shaped structures that we term Lambda-precursors. An early marker of initiation was the gradual coalescence of GFP-vasodilator-stimulated phosphoprotein (GFP-VASP) fluorescence at the leading edge into discrete foci. The GFP-VASP foci were associated with Lambda-precursors, whereas Arp2/3 was not. Subsequent recruitment of fascin to the clustered barbed ends of Lambda-precursors initiated filament bundling and completed formation of the nascent filopodium. We propose a convergent elongation model of filopodia initiation, stipulating that filaments within the lamellipodial dendritic network acquire privileged status by binding a set of molecules (including VASP) to their barbed ends, which protect them from capping and mediate association of barbed ends with each other.

  9. Reorganization of the North Atlantic Oscillation during early Holocene deglaciation

    Science.gov (United States)

    Wassenburg, Jasper A.; Dietrich, Stephan; Fietzke, Jan; Fohlmeister, Jens; Jochum, Klaus Peter; Scholz, Denis; Richter, Detlev K.; Sabaoui, Abdellah; Spötl, Christoph; Lohmann, Gerrit; Andreae, Meinrat O.; Immenhauser, Adrian

    2016-08-01

    The North Atlantic Oscillation is the dominant atmospheric pressure mode in the North Atlantic region and affects winter temperature and precipitation in the Mediterranean, northwest Europe, Greenland, and Asia. The index that describes the sea-level pressure difference between Iceland and the Azores is correlated with a dipole precipitation pattern over northwest Europe and northwest Africa. How the North Atlantic Oscillation will develop as the Greenland ice sheet melts is unclear. A potential past analogue is the early Holocene, during which melting ice sheets around the North Atlantic freshened surface waters, affecting the strength of the meridional overturning circulation. Here we present a Holocene rainfall record from northwest Africa based on speleothem δ18O and compare it against a speleothem-based rainfall record from Europe. The two records are positively correlated during the early Holocene, followed by a shift to an anti-correlation, similar to the modern record, during the mid-Holocene. On the basis of our simulations with an Earth system model, we suggest the shift to the anti-correlation reflects a large-scale atmospheric and oceanic reorganization in response to the demise of the Laurentide ice sheet and a strong reduction of meltwater flux to the North Atlantic, pointing to a potential sensitivity of the North Atlantic Oscillation to the melting of ice sheets.

  10. Global reorganization of the nuclear landscape in senescent cells.

    Science.gov (United States)

    Chandra, Tamir; Ewels, Philip Andrew; Schoenfelder, Stefan; Furlan-Magaril, Mayra; Wingett, Steven William; Kirschner, Kristina; Thuret, Jean-Yves; Andrews, Simon; Fraser, Peter; Reik, Wolf

    2015-02-03

    Cellular senescence has been implicated in tumor suppression, development, and aging and is accompanied by large-scale chromatin rearrangements, forming senescence-associated heterochromatic foci (SAHF). However, how the chromatin is reorganized during SAHF formation is poorly understood. Furthermore, heterochromatin formation in senescence appears to contrast with loss of heterochromatin in Hutchinson-Gilford progeria. We mapped architectural changes in genome organization in cellular senescence using Hi-C. Unexpectedly, we find a dramatic sequence- and lamin-dependent loss of local interactions in heterochromatin. This change in local connectivity resolves the paradox of opposing chromatin changes in senescence and progeria. In addition, we observe a senescence-specific spatial clustering of heterochromatic regions, suggesting a unique second step required for SAHF formation. Comparison of embryonic stem cells (ESCs), somatic cells, and senescent cells shows a unidirectional loss in local chromatin connectivity, suggesting that senescence is an endpoint of the continuous nuclear remodelling process during differentiation. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  11. Structural reorganization of cylindrical nanoparticles triggered by polylactide stereocomplexation

    Science.gov (United States)

    Sun, Liang; Pitto-Barry, Anaïs; Kirby, Nigel; Schiller, Tara L.; Sanchez, Ana M.; Dyson, M. Adam; Sloan, Jeremy; Wilson, Neil R.; O'Reilly, Rachel K.; Dove, Andrew P.

    2014-12-01

    Co-crystallization of polymers with different configurations/tacticities provides access to materials with enhanced performance. The stereocomplexation of isotactic poly(L-lactide) and poly(D-lactide) has led to improved properties compared with each homochiral material. Herein, we report the preparation of stereocomplex micelles from a mixture of poly(L-lactide)-b-poly(acrylic acid) and poly(D-lactide)-b-poly(acrylic acid) diblock copolymers in water via crystallization-driven self-assembly. During the formation of these stereocomplex micelles, an unexpected morphological transition results in the formation of dense crystalline spherical micelles rather than cylinders. Furthermore, mixture of cylinders with opposite homochirality in either THF/H2O mixtures or in pure water at 65 °C leads to disassembly into stereocomplexed spherical micelles. Similarly, a transition is also observed in a related PEO-b-PLLA/PEO-b-PDLA system, demonstrating wider applicability. This new mechanism for morphological reorganization, through competitive crystallization and stereocomplexation and without the requirement for an external stimulus, allows for new opportunities in controlled release and delivery applications.

  12. Reorganization of the Brain and Heart Rhythm During Autogenic Meditation

    Directory of Open Access Journals (Sweden)

    Dae-Keun eKim

    2014-01-01

    Full Text Available The underlying changes in heart coherence that are associated with reported EEG changes in response to meditation have been explored. We measured EEG and heart rate variability (HRV before and during autogenic meditation. Fourteen subjects participated in the study. Heart coherence scores were significantly increased during meditation compared to the baseline. We found near significant decrease in high beta absolute power, increase in alpha relative power and significant increases in lower(alpha and higher(above beta band coherence during 3 minute epochs of heart coherent meditation compared to 3 minute epochs of heart noncoherence at baseline. The coherence and relative power increase in alpha band and absolute power decrease in high beta band could reflect relaxation state during the heart coherent meditation. The coherence increase in the higher(above beta band could reflect cortico-cortical local integration and thereby affect cognitive reorganization, simultaneously with relaxation. Further research is still needed for a confirmation of heart coherence as a simple window for the meditative state.

  13. Linking genomic reorganization to tumor initiation via the giant cell cycle

    Science.gov (United States)

    Niu, N; Zhang, J; Zhang, N; Mercado-Uribe, I; Tao, F; Han, Z; Pathak, S; Multani, A S; Kuang, J; Yao, J; Bast, R C; Sood, A K; Hung, M-C; Liu, J

    2016-01-01

    To investigate the mechanisms underlying our recent paradoxical finding that mitotically incapacitated and genomically unstable polyploid giant cancer cells (PGCCs) are capable of tumor initiation, we labeled ovarian cancer cells with α-tubulin fused to green fluorescent protein, histone-2B fused to red fluorescent protein and FUCCI (fluorescent ubiquitination cell cycle indicator), and tracked the spatial and time-dependent change in spindle and chromosomal dynamics of PGCCs using live-cell fluorescence time-lapse recording. We found that single-dose (500 nm) treatment with paclitaxel paradoxically initiated endoreplication to form PGCCs after massive cell death. The resulting PGCCs continued self-renewal via endoreplication and further divided by nuclear budding or fragmentation; the small daughter nuclei then acquired cytoplasm, split off from the giant mother cells and acquired competency in mitosis. FUCCI showed that PGCCs divided via truncated endoreplication cell cycle (endocycle or endomitosis). Confocal microscopy showed that PGCCs had pronounced nuclear fragmentation and lacked expression of key mitotic proteins. PGCC-derived daughter cells were capable of long-term proliferation and acquired numerous new genome/chromosome alterations demonstrated by spectral karyotyping. These data prompt us to conceptualize a giant cell cycle composed of four distinct but overlapping phases, initiation, self-renewal, termination and stability. The giant cell cycle may represent a fundamental cellular mechanism to initiate genomic reorganization to generate new tumor-initiating cells in response to chemotherapy-induced stress and contributes to disease relapse. PMID:27991913

  14. Toddlers actively reorganize their whole body coordination to maintain walking stability while carrying an object.

    Science.gov (United States)

    Hsu, Wen-Hao; Miranda, Daniel L; Chistolini, Trevor L; Goldfield, Eugene C

    2016-10-01

    Balanced walking involves freely swinging the limbs like pendula. However, children immediately begin to carry objects as soon as they can walk. One possibility for this early skill development is that whole body coordination during walking may be re-organized into loosely coupled collections of body parts, allowing children to use their arms to perform one function, while the legs perform another. Therefore, this study examines: 1) how carrying an object affects the coordination of the arms and legs during walking, and 2) if carrying an object influences stride length and width. Ten healthy toddlers with 3-12 months of walking experience were recruited to walk barefoot while carrying or not carrying a small toy. Stride length, width, speed, and continuous relative phase (CRP) of the hips and of the shoulders were compared between carrying conditions. While both arms and legs demonstrated destabilization and stabilization throughout the gait cycle, the arms showed a reduction in intra-subject coordination variability in response to carrying an object. Carrying an object may modify the function of the arms from swinging for balance to maintaining hold of an object. The observed period-dependent changes of the inter-limb coordination of the hips and of the shoulders also support this interpretation. Overall, these findings support the view that whole-body coordination patterns may become partitioned in particular ways as a function of task requirements.

  15. Chemosensory Learning in the Cortex

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    Edmund eRolls

    2011-09-01

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

  16. Cortical network reorganization guided by sensory input features.

    Science.gov (United States)

    Kilgard, Michael P; Pandya, Pritesh K; Engineer, Navzer D; Moucha, Raluca

    2002-12-01

    Sensory experience alters the functional organization of cortical networks. Previous studies using behavioral training motivated by aversive or rewarding stimuli have demonstrated that cortical plasticity is specific to salient inputs in the sensory environment. Sensory experience associated with electrical activation of the basal forebrain (BasF) generates similar input specific plasticity. By directly engaging plasticity mechanisms and avoiding extensive behavioral training, BasF stimulation makes it possible to efficiently explore how specific sensory features contribute to cortical plasticity. This review summarizes our observations that cortical networks employ a variety of strategies to improve the representation of the sensory environment. Different combinations of receptive-field, temporal, and spectrotemporal plasticity were generated in primary auditory cortex neurons depending on the pitch, modulation rate, and order of sounds paired with BasF stimulation. Simple tones led to map expansion, while modulated tones altered the maximum cortical following rate. Exposure to complex acoustic sequences led to the development of combination-sensitive responses. This remodeling of cortical response characteristics may reflect changes in intrinsic cellular mechanisms, synaptic efficacy, and local neuronal connectivity. The intricate relationship between the pattern of sensory activation and cortical plasticity suggests that network-level rules alter the functional organization of the cortex to generate the most behaviorally useful representation of the sensory environment.

  17. Bilateral experimental neck pain reorganize axioscapular muscle coordination and pain sensitivity

    DEFF Research Database (Denmark)

    Christensen, Steffan Wittrup; Hirata, Rogerio Pessoto; Graven-Nielsen, Thomas

    2017-01-01

    BACKGROUND: Neck pain is a large clinical problem where reorganized trunk and axioscapular muscle activities have been hypothesised contributing to pain persistence and pain hypersensitivity. This study investigated the effects of bilateral experimental neck pain on trunk and axioscapular muscle ...

  18. Reorganization energy of the CuA center in purple azurin

    DEFF Research Database (Denmark)

    Farver, Ole; Hwang, Hee Jung; Pecht, Israel

    2007-01-01

    shown that lowering the pH from 8.0 to 4.0 results in a similar (~0.4 eV) decrease in reorganization energy for both blue (type 1) and purple (CuA) azurins, even though the reorganization energies of the two different copper centers are different at a given pH. These results suggest that the MV state...

  19. Single-sphere model for solvent reorganization energy and its application to electron transfer

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In this work, the authors give detailed deductions and develop the single-sphere model of solvent reorganization energy in electron transfer with point dipole approximation. At the level of DFT/6- 31++G**, the electron transfer between 7,7,8,8-tetracyanoquinodimethane and its anion has been investigated. Using the novel single-sphere model, the authors evaluate the solvent reorganization energy of this system, and the computational result proves rational in comparison with the experimental estimations.

  20. Motor unit reorganization in progressive muscular dystrophies and congenital myopathies.

    Science.gov (United States)

    Szmidt-Sałkowska, Elżbieta; Gaweł, Małgorzata; Lipowska, Marta

    2015-01-01

    The aim of this study was to analyze motor unit reorganization in different types of progressive muscular dystrophies and congenital myopathies. The study population consisted of patients with genetically verified progressive muscular dystrophies: Duchenne (DMD) (n=54), Becker (BMD) (n=30), facio-scapulo-humeral (FSHD) (n=37), and Emery-Dreifuss (E-DD) (n=26). Patients with probable limb-girdle dystrophy (L-GD) (n=58) and congenital myopathies (n=35) were also included in the study. Quantitative EMG recordings were obtained from 469 muscles. Muscle activity at rest and during slight voluntary and maximal muscle contraction was analyzed. The motor unit activity potential (MUAP) duration, amplitude, area, size index (SI), polyphasicity, and the presence of "outliers" were evaluated. Diminished values of MUAP parameters and decreased maximal amplitude of maximal muscle contraction were recorded most frequently in DMD and mainly in the biceps brachii muscles. SI was the most frequently changed EMG parameter. "Outliers" with amplitude below the normal range were recorded more frequently then a decreased mean MUAP amplitude (what could indicate a very high sensitivity of this EMG parameter). Pathological interference pattern was recorded in 34.7% of biceps brachii and in 21.2% of rectus femoris muscles. In FSHD, decreased MUAP duration and SI and pathological interference pattern with low amplitude were recorded most frequently in the tibial anterior and deltoid muscles. The presence of potentials with reduced parameters is a result of decreasing motor unit area (reduced number and size of muscle fibers), while high amplitude potentials recorded in BMD and E-DD could indicate a slow and mild course of disease and muscle regeneration.

  1. The effects of acute heat stress on proliferative and apoptotic processes in the rat adrenal cortex

    Directory of Open Access Journals (Sweden)

    Petrović-Kosanović Dragana

    2013-01-01

    Full Text Available Hyperthermia can cause significant structural and functional reorganization of tissues and organs. The proliferative and apoptotic processes of rat adrenal cortex were analyzed by light and electron microscopy after an acute exposure to high ambient temperature. Animals were divided in two groups. The first group consisted of intact controls. The rats from the second group were exposed to a high ambient temperature of 38°C for 60 min. Mitotic chromosomes and the largest number of immunoreactive nuclei for the Ki-67 were observed in the zona reticularis (ZR of the control animals. The relative number of mitoses after heat stress showed a significant decrease in the zona glomerulosa (ZG; 66.8%, zona fasciculata (ZF; 27.8% and ZR (86.7% (for all zones p<0.05, while in the whole adrenal cortex the after-treatment decrease was 61.9% (p<0.05 compared to the controls. Under heat stress numerous apoptotic nuclei were seen at the light and ultrastructural levels in all the zones of the adrenal cortex. Such dynamics of mitosis/apoptosis events seriously affect adrenal cortex morphology. [Projekat Ministarstva nauke Republike Srbije, br. 173023 i br. 173009

  2. Molecular networks linked by Moesin drive remodeling of the cell cortex during mitosis

    Science.gov (United States)

    Roubinet, Chantal; Decelle, Barbara; Chicanne, Gaëtan; Dorn, Jonas F.; Payrastre, Bernard; Payre, François; Carreno, Sébastien

    2011-01-01

    The cortical mechanisms that drive the series of mitotic cell shape transformations remain elusive. In this paper, we identify two novel networks that collectively control the dynamic reorganization of the mitotic cortex. We demonstrate that Moesin, an actin/membrane linker, integrates these two networks to synergize the cortical forces that drive mitotic cell shape transformations. We find that the Pp1-87B phosphatase restricts high Moesin activity to early mitosis and down-regulates Moesin at the polar cortex, after anaphase onset. Overactivation of Moesin at the polar cortex impairs cell elongation and thus cytokinesis, whereas a transient recruitment of Moesin is required to retract polar blebs that allow cortical relaxation and dissipation of intracellular pressure. This fine balance of Moesin activity is further adjusted by Skittles and Pten, two enzymes that locally produce phosphoinositol 4,5-bisphosphate and thereby, regulate Moesin cortical association. These complementary pathways provide a spatiotemporal framework to explain how the cell cortex is remodeled throughout cell division. PMID:21969469

  3. Quaternary Reorganization of North American Mid-continent Drainage Systems

    Science.gov (United States)

    Carson, E. C.; Rawling, J. E., III; Attig, J. W.; Bates, B. R.

    2013-12-01

    changes to the total discharge of the St. Lawrence and Mississippi Rivers. While it is unclear if the Teays River ever flowed into the St. Lawrence drainage or developed as a westward-flowing tributary to the buried Mahomet valley in Illinois, both the ancestral Pittsburgh and Wyalusing Rivers originated as headwaters of the St. Lawrence basin before being rerouted as part of the Mississippi basin. The areas formerly drained by the Pittsburgh and Wyalusing Rivers comprise ~8% of the modern Mississippi River basin, and modern discharge from those areas represent ~14% of the mean annual discharge of the Mississippi River. The transfer of this drainage area and discharge to the Mississippi basin is mirrored by an equivalent loss from the St. Lawrence system during the Quaternary as a direct result of glacially-driven drainage system reorganization.

  4. Finger somatotopy in human motor cortex.

    Science.gov (United States)

    Beisteiner, R; Windischberger, C; Lanzenberger, R; Edward, V; Cunnington, R; Erdler, M; Gartus, A; Streibl, B; Moser, E; Deecke, L

    2001-06-01

    Although qualitative reports about somatotopic representation of fingers in the human motor cortex exist, up to now no study could provide clear statistical evidence. The goal of the present study was to reinvestigate finger motor somatotopy by means of a thorough investigation of standardized movements of the index and little finger of the right hand. Using high resolution fMRI at 3 Tesla, blood oxygenation level-dependent (BOLD) responses in a group of 26 subjects were repeatedly measured to achieve reliable statistical results. The center of mass of all activated voxels within the primary motor cortex was calculated for each finger and each run. Results of all runs were averaged to yield an individual index and little finger representation for each subject. The mean center of mass localizations for all subjects were then submitted to a paired t test. Results show a highly significant though small scale somatotopy of fingerspecific activation patterns in the order indicated by Penfields motor homunculus. In addition, considerable overlap of finger specific BOLD responses was found. Comparing various methods of analysis, the mean center of mass distance for the two fingers was 2--3 mm with overlapping voxels included and 4--5 mm with overlapping voxels excluded. Our data may be best understood in the context of the work of Schieber (1999) who recently described overlapping somatotopic gradients in lesion studies with humans. Copyright 2001 Academic Press.

  5. Burnout in health-care professionals during reorganizations and downsizing. A cohort study in nurses

    Directory of Open Access Journals (Sweden)

    Hall-Lord Marie-Louise

    2010-06-01

    Full Text Available Abstract Background Burnout is a psychological reaction triggered by interaction between personal characteristics and stress factors. Reorganizations and downsizing with increased workload imply stress for health-care professionals. This is a study of burnout in nurses during a period with two comprehensive reorganizations. Methods In this quasi-experimental retrospective cohort study, burnout was assessed in nurses with long work experience in three surveys during a 30 months' period with two comprehensive reorganizations and downsizing of a hospital unit with mostly seriously ill patients with cancer. Burnout was measured with Bergen Burnout Indicator (BBI at each survey, and "Sense of Coherence" (SOC with Antonovsky's questionnaire at the last survey. Results One man and 45 women aged 30 to 65 years were invited to the surveys. There was a significant increase in burnout during the study period, the mean increase in BBI-score was 12.5 pr year (p Conclusions There was a significant development of burnout in a group of nurses during a period with two reorganizations and downsizing. Burnout was associated with low SOC. Working with seriously ill patients with cancer has probably made the nurses exceptionally vulnerable to the stress and workload related to the reorganizations.

  6. A modified two-sphere model for solvent reorganization energy in electron transfer.

    Science.gov (United States)

    Wu, Han-Yu; Ren, Hai-Sheng; Zhu, Quan; Li, Xiang-Yuan

    2012-04-28

    In this work, the solvent reorganization energy is formulated within the framework of classical thermodynamics, by adding some external charges to construct a constrained equilibrium state. The derivation clearly shows that the reorganization energy is exactly the polarization cost for the inertial part of the polarization. We perform our derivation just within the framework of the first law of thermodynamics, and the final form of the reorganization energy is completely the same as that we gave in our recent work by defining a nonequilibrium solvation free energy. With the two-sphere model approximation, our solvent reorganization energy is derived as λ(0) = Δq(2)/2[1/r(D) + 1/r(A) - 2/d][(ε(-1)(op) - ε(-1)(s))/(1 - ε(-1)(s))]. This amends Marcus' model by a factor of (ε(-1)(op) - ε(-1)(s))/(1 - ε(-1)(s)), which is coupled with the solvent polarity. Making use of the modified expression of solvent reorganization energy, two recently reported electron transfer processes are investigated in representative solvents. The results show that our formula can well reproduce the experimental observations. This journal is © the Owner Societies 2012

  7. Immunoprofiling of rice root cortex reveals two cortical subdomains

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    Sophia eHenry

    2016-01-01

    Full Text Available The formation and differentiation of aerenchyma, i.e., air-containing cavities that are critical for flooding tolerance, take place exclusively in the cortex. The understanding of development and differentiation of the cortex is thus an important issue; however, studies on this tissue are limited, partly because of the lack of available molecular tools. We screened a commercially available library of cell wall antibodies to identify markers of cortical tissue in rice roots. Out of the 174 antibodies screened, eight were cortex-specific. Our analysis revealed that two types of cortical tissues are present in rice root seedlings. We named these cell layers 'inner' and 'outer' based on their location relative to the stele. We then used the antibodies to clarify cell identity in lateral roots. Without these markers, previous studies could not distinguish between the cortex and sclerenchyma in small lateral roots. By immunostaining lateral root sections, we showed that the internal ground tissue in small lateral roots has outer cortical identity.

  8. DESCRIPTION OF THE ORGANIZATIONAL AND TECHNOLOGICAL PROCESSES ON THE GROUND OF THE BASIC MODEL OF THE CYCLE OF REORGANIZATION

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    Gazaryan Robert Kamoevich

    2012-12-01

    Full Text Available The objective of this scientific research is application of the basic model of interaction between phases of a cycle of reorganization of organizational and technological processes underway at industrial enterprises. The authors describe interactions between all six phases of the process of reorganization within the framework of the basic model of a cycle that contemplates organizational and technological processes. Engineering studies are necessary to check for the feasibility of reorganization of industrial enterprises and application of results extracted from the design documentation with a view to reorganization of production activities and construction operations. Upon completion of the decision-making process concerning the need for reorganization in accordance with the basic model of interaction between phases, there occurs restructuring that incorporates processes of design and construction. The authors have demonstrated that reorganization of the basic model cycle should be used in the design of organizational and technological processes with a view to the integrated consideration of reorganization of enterprises in order to comprehend and improve the efficiency of reorganization at each stage, as well as the control over the reorganization of a construction facility.

  9. A molecular Debye-Hückel approach to the reorganization energy of electron transfer reactions in an electric cell.

    Science.gov (United States)

    Xiao, Tiejun; Song, Xueyu

    2014-10-07

    Electron transfer near an electrode immersed in ionic fluids is studied using the linear response approximation, namely, mean value of the vertical energy gap can be used to evaluate the reorganization energy, and hence any linear response model that can treat Coulomb interactions successfully can be used for the reorganization energy calculation. Specifically, a molecular Debye-Hückel theory is used to calculate the reorganization energy of electron transfer reactions in an electric cell. Applications to electron transfer near an electrode in molten salts show that the reorganization energies from our molecular Debye-Hückel theory agree well with the results from MD simulations.

  10. A major reorganization of Asian climate by the early Miocene

    Directory of Open Access Journals (Sweden)

    Z. T. Guo

    2008-08-01

    circulations, one from the ocean carrying moisture and another from the inland deserts transporting dust. The formation of the early Miocene paleosols resulted from interactive soil forming and dust deposition processes in these two seasonally alternating monsoonal circulations. The much stronger development of the early Miocene soils compared to those in the Quaternary loess indicates that summer monsoons were either significantly stronger, more persistent through the year, or both.

    These lines of evidence indicate a joint change in circulation and inland aridity by the early Miocene and suggest a dynamic linkage of them. Our recent sensitivity tests with a general circulation model, along with relevant geological data, suggest that the onset of these contrasting wet/dry responses, as well as the change from the "planetary" subtropical aridity pattern to the "inland" aridity pattern, resulted from the combined effects of Tibetan uplift and withdrawal of the Paratethys seaway in central Asia, as suggested by earlier experiments. The spreading of South China Sea also helped to enhance the south-north contrast of humidity. The Miocene loess record provides a vital insight that these tectonic factors had evolved by the early Miocene to a threshold sufficient to cause this major climate reorganization in Asia.

  11. Monkey brain cortex imaging by photoacoustic tomography

    OpenAIRE

    Yang, Xinmai; Wang, Lihong V.

    2008-01-01

    Photoacoustic tomography (PAT) is applied to image the brain cortex of a monkey through the intact scalp and skull ex vivo. The reconstructed PAT image shows the major blood vessels on the monkey brain cortex. For comparison, the brain cortex is imaged without the scalp, and then imaged again without the scalp and skull. Ultrasound attenuation through the skull is also measured at various incidence angles. This study demonstrates that PAT of the brain cortex is capable of surviving the ultras...

  12. [Structural and functional reorganization of photosynthetic apparatus in cold adaptation of wheat plants].

    Science.gov (United States)

    Venzhik, Ju V; Titov, D F; Talanova, V V; Miroslavov, E D; Koteeva, N K

    2012-01-01

    The structural and functional characteristics of the photosynthetic apparatus (PSA) and the cold resistance of wheat seedlings were studied during low-temperature adaptation. It has been established that large chloroplasts with thylakoid system of "sun type" forme in the mesophyll cells in the early hours of plants hardening. At the same time the functional reorganization of the PSA in the leaves of wheat occurs: content of pigments changes, stabilization of the pigment-protein complexes is observed, non-photochemical quenching of excess energy increases. The stabilization of photosynthesis during cold adaptation occurs due to structural and functional reorganization of the PSA. It is assumed that the reorganization of the PSA is a prerequisite for formation of increased cold resistance of leaf cells, and this, along with other physiological and biochemical changes occurring in cells and tissues of plants, allows the plants to survive in chilling.

  13. Heterochromatin Reorganization during Early Mouse Development Requires a Single-Stranded Noncoding Transcript

    Directory of Open Access Journals (Sweden)

    Miguel Casanova

    2013-09-01

    Full Text Available The equalization of pericentric heterochromatin from distinct parental origins following fertilization is essential for genome function and development. The recent implication of noncoding transcripts in this process raises questions regarding the connection between RNA and the nuclear organization of distinct chromatin environments. Our study addresses the interrelationship between replication and transcription of the two parental pericentric heterochromatin (PHC domains and their reorganization during early embryonic development. We demonstrate that the replication of PHC is dispensable for its clustering at the late two-cell stage. In contrast, using parthenogenetic embryos, we show that pericentric transcripts are essential for this reorganization independent of the chromatin marks associated with the PHC domains. Finally, our discovery that only reverse pericentric transcripts are required for both the nuclear reorganization of PHC and development beyond the two-cell stage challenges current views on heterochromatin organization.

  14. Axonal dynamics of excitatory and inhibitory neurons in somatosensory cortex.

    Directory of Open Access Journals (Sweden)

    Sally A Marik

    Full Text Available Cortical topography can be remapped as a consequence of sensory deprivation, suggesting that cortical circuits are continually modified by experience. To see the effect of altered sensory experience on specific components of cortical circuits, we imaged neurons, labeled with a genetically modified adeno-associated virus, in the intact mouse somatosensory cortex before and after whisker plucking. Following whisker plucking we observed massive and rapid reorganization of the axons of both excitatory and inhibitory neurons, accompanied by a transient increase in bouton density. For horizontally projecting axons of excitatory neurons there was a net increase in axonal projections from the non-deprived whisker barrel columns into the deprived barrel columns. The axon collaterals of inhibitory neurons located in the deprived whisker barrel columns retracted in the vicinity of their somata and sprouted long-range projections beyond their normal reach towards the non-deprived whisker barrel columns. These results suggest that alterations in the balance of excitation and inhibition in deprived and non-deprived barrel columns underlie the topographic remapping associated with sensory deprivation.

  15. The Functions of the Orbitofrontal Cortex

    Science.gov (United States)

    Rolls, Edmund T.

    2004-01-01

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

  16. Evolutionary specializations of human association cortex

    NARCIS (Netherlands)

    Mars, R.B.; Passingham, R.E.; Neubert, F.X.; Verhagen, L.; Sallet, J.

    2017-01-01

    Is the human brain a big ape brain? We argue that the human association cortex is larger than would be expected for an equivalent ape brain, suggesting human association cortex is a unique adaptation. The internal organization of the human association cortex shows modifications of the ape plan in

  17. Physiological reorganization in the hypotrich ciliate Apoamphisiella vernalis (Protista, Ciliophora, Hypotricha

    Directory of Open Access Journals (Sweden)

    Larissa A. M. de Castro

    Full Text Available ABSTRACT Physiological reorganization is described for the first time for the hypotrich ciliate genus Apoamphisiella Foissner, 1997, based on a population of A. vernalis (Stokes, 1887 Berger, 2006 collected from an eutrophic pond in the state of Minas Gerais, Brazil. Stomatogenesis is epiapokinetal, and the cirral pattern reorganizes from six typical fronto-ventral-transverse primordia, plus at least one short primordium located between IV and V. Primordia I and II originate from disaggregating undulating membranes and buccal cirrus, respectively; primordium III originates from left frontoventral cirrus plus a streak of basal bodies extending from the anterior end of oral primordium; primordium IV and the short extra primordia are formed from basal bodies perhaps associated to the posterior end of III plus the disaggregation of anteriormost cirri of the left ventral row. Primordia V and VI arise within the right ventral row as a single streak, splitting to form the two primordia. Marginal primordia develop initially within the pre-existent marginal rows, continuing to reorganize outside, pushing the old marginal cirri leftwards. Two dorsomarginal kineties develop associated to the right marginal row primordium. Dorsal ciliature also reorganizes from within the pre-existent dorsal kineties. The two macronuclear nodules approach each in middle reorganizers, briefly touching each other. At least one micronucleus undergo division. The process of physiological reorganization in A. vernalis resembles that of the North American Paraurostyla weissei complex representative, and along with features of the interphase morphology, indicate that Apoamphisiella belongs or is related to the Cyrtohymena-Paraurostyla group, within the Dorsomarginalia.

  18. Consolidation of visual associative long-term memory in the temporal cortex of primates.

    Science.gov (United States)

    Miyashita, Y; Kameyama, M; Hasegawa, I; Fukushima, T

    1998-01-01

    Neuropsychological theories have proposed a critical role for the interaction between the medial temporal lobe and the neocortex in the formation of long-term memory for facts and events, which has often been tested by learning of a series of paired words or figures in humans. We have examined neural mechanisms underlying the memory "consolidation" process by single-unit recording and molecular biological methods in an animal model of a visual pair-association task in monkeys. In our previous studies, we found that long-term associative representations of visual objects are acquired through learning in the neural network of the anterior inferior temporal (IT) cortex. In this article, we propose the hypothesis that limbic neurons undergo rapid modification of synaptic connectivity and provide backward signals that guide the reorganization of neocortical neural circuits. Two experiments tested this hypothesis: (1) we examined the role of the backward connections from the medial temporal lobe to the IT cortex by injecting ibotenic acid into the entorhinal and perirhinal cortices, which provided massive backward projections ipsilaterally to the IT cortex. We found that the limbic lesion disrupted the associative code of the IT neurons between the paired associates, without impairing the visual response to each stimulus. (2) We then tested the first half of this hypothesis by detecting the expression of immediate-early genes in the monkey temporal cortex. We found specific expression of zif268 during the learning of a new set of paired associates in the pair-association task, most intensively in area 36 of the perirhinal cortex. All these results with the visual pair-association task support our hypothesis and demonstrate that the consolidation process, which was first proposed on the basis of clinico-psychological evidence, can now be examined in primates using neurophysiolocical and molecular biological approaches.

  19. Transcranial static magnetic field stimulation of the human motor cortex.

    Science.gov (United States)

    Oliviero, Antonio; Mordillo-Mateos, Laura; Arias, Pablo; Panyavin, Ivan; Foffani, Guglielmo; Aguilar, Juan

    2011-10-15

    The aim of the present study was to investigate in healthy humans the possibility of a non-invasive modulation of motor cortex excitability by the application of static magnetic fields through the scalp. Static magnetic fields were obtained by using cylindrical NdFeB magnets. We performed four sets of experiments. In Experiment 1, we recorded motor potentials evoked by single-pulse transcranial magnetic stimulation (TMS) of the motor cortex before and after 10 min of transcranial static magnetic field stimulation (tSMS) in conscious subjects. We observed an average reduction of motor cortex excitability of up to 25%, as revealed by TMS, which lasted for several minutes after the end of tSMS, and was dose dependent (intensity of the magnetic field) but not polarity dependent. In Experiment 2, we confirmed the reduction of motor cortex excitability induced by tSMS using a double-blind sham-controlled design. In Experiment 3, we investigated the duration of tSMS that was necessary to modulate motor cortex excitability. We found that 10 min of tSMS (compared to 1 min and 5 min) were necessary to induce significant effects. In Experiment 4, we used transcranial electric stimulation (TES) to establish that the tSMS-induced reduction of motor cortex excitability was not due to corticospinal axon and/or spinal excitability, but specifically involved intracortical networks. These results suggest that tSMS using small static magnets may be a promising tool to modulate cerebral excitability in a non-invasive, painless, and reversible way.

  20. Spike-timing-dependent potentiation of sensory surround in the somatosensory cortex is facilitated by deprivation-mediated disinhibition.

    Science.gov (United States)

    Gambino, Frédéric; Holtmaat, Anthony

    2012-08-09

    Functional maps in the cerebral cortex reorganize in response to changes in experience, but the synaptic underpinnings remain uncertain. Here, we demonstrate that layer (L) 2/3 pyramidal cell synapses in mouse barrel cortex can be potentiated upon pairing of whisker-evoked postsynaptic potentials (PSPs) with action potentials (APs). This spike-timing-dependent long-term potentiation (STD-LTP) was only effective for PSPs evoked by deflections of a whisker in the neuron's receptive field center, and not its surround. Trimming of all except two whiskers rapidly opened the possibility to drive STD-LTP by the spared surround whisker. This facilitated STD-LTP was associated with a strong decrease in the surrounding whisker-evoked inhibitory conductance and partially occluded picrotoxin-mediated LTP facilitation. Taken together, our data demonstrate that sensory deprivation-mediated disinhibition facilitates STD-LTP from the sensory surround, which may promote correlation- and experience-dependent expansion of receptive fields.

  1. Thermo-optically induced reorganizations in the main light harvesting antenna of plants. II

    DEFF Research Database (Denmark)

    Holm, Jens Kai; Varkonyi, Zsuzsanna; Kovacs, Laszlo

    2005-01-01

    from the same membranes. These reorganizations have earlier been assigned to originate from a thermo-optic effect. According to the thermo-optic mechanism, fast local thermal transients due to dissipation of the excess excitation energy induce elementary structural changes in the close vicinity......, together with other close similarities between the two systems, strongly suggests that the gross short-term, thermo-optically induced structural reorganizations in the membranes occur mainly, albeit probably not exclusively, in the LHCII-only domains [Boekema et al. (2000) J Mol Biol 301: 1123–1133]. Hence...

  2. Reorganization and plastic changes of the human brain associated with skill learning and expertise

    Directory of Open Access Journals (Sweden)

    Yongmin eChang

    2014-02-01

    Full Text Available Novel experience and learning new skills are known as modulators of brain function. Advances in non-invasive brain imaging have provided new insight into structural and functional reorganization associated with skill learning and expertise. Especially, significant imaging evidences come from the domains of sports and music. Data from in vivo imaging studies in sports and music have provided vital information on plausible neural substrates contributing to brain reorganization underlying skill acquisition in humans. This mini review will attempt to take a narrow snapshot of imaging findings demonstrating functional and structural plasticity that mediate skill learning and expertise while identifying converging areas of interest and possible avenues for future research.

  3. М. SCHUMPETER’S INNOVATION PARADIGM AND PRINCIPLES OF ECONOMIC SYSTEM REORGANIZATION

    Directory of Open Access Journals (Sweden)

    M. Kravchenko

    2013-03-01

    Full Text Available The paper is devoted to the principles of the reorganization of the economic system of Ukraine. The principles of the economic system reorganization presented in the paper as a consequence Schumpeter’s theory of economic development. The main idea of the article is that institutions of modern society should systematically promote the establishment, operation and development of a new appropriation form that follows from both the role of innovation as a factor in Schumpeter’s theory of economic development and the role of social factors.

  4. Motor Cortex Plasticity during Unilateral Finger Movement with Mirror Visual Feedback

    Directory of Open Access Journals (Sweden)

    Hatice Kumru

    2016-01-01

    Full Text Available Plasticity is one of the most important physiological mechanisms underlying motor recovery from brain lesions. Rehabilitation methods, such as mirror visual feedback therapy, which are based on multisensory integration of motor, cognitive, and perceptual processes, are considered effective methods to induce cortical reorganization. The present study investigated 3 different types of visual feedback (direct, mirrored, and blocked visual feedback: DVF, MVF, and BVF, resp. on M1 cortex excitability and intracortical inhibition/facilitation at rest and during phasic unimanual motor task in 11 healthy individuals. The excitability of the ipsilateral M1 cortex and the intracortical facilitation increased during motor task performance in the DVF and MVF but not in the BVF condition. In addition, MVF induced cortical disinhibition of the ipsilateral hemisphere to the index finger performing the motor task, which was greater when compared to the BVF and restricted to the homologue first dorsal interosseous muscle. The visual feedback is relevant to M1 cortex excitability modulation but the MVF plays a crucial role in promoting changes in intracortical inhibition in comparison to BVF. Altogether, it can be concluded that a combination of motor training with MVF therapy may induce more robust neuroplastic changes through multisensory integration that is relevant to motor rehabilitation.

  5. Parietal cortex mediates perceptual Gestalt grouping independent of stimulus size.

    Science.gov (United States)

    Grassi, Pablo R; Zaretskaya, Natalia; Bartels, Andreas

    2016-06-01

    The integration of local moving elements into a unified gestalt percept has previously been linked to the posterior parietal cortex. There are two possible interpretations for the lack of involvement of other occipital regions. The first is that parietal cortex is indeed uniquely functionally specialized to perform grouping. Another possibility is that other visual regions can perform grouping as well, but that the large spatial separation of the local elements used previously exceeded their neurons' receptive field (RF) sizes, preventing their involvement. In this study we distinguished between these two alternatives. We measured whole-brain activity using fMRI in response to a bistable motion illusion that induced mutually exclusive percepts of either an illusory global Gestalt or of local elements. The stimulus was presented in two sizes, a large version known to activate IPS only, and a version sufficiently small to fit into the RFs of mid-level dorsal regions such as V5/MT. We found that none of the separately localized motion regions apart from parietal cortex showed a preference for global Gestalt perception, even for the smaller version of the stimulus. This outcome suggests that grouping-by-motion is mediated by a specialized size-invariant mechanism with parietal cortex as its anatomical substrate. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Inter-hemispheric language functional reorganization in low-grade glioma patients after tumour surgery

    NARCIS (Netherlands)

    Kristo, Gert; Raemaekers, Mathijs; Rutten, Geert Jan; de Gelder, Beatrice; Ramsey, Nick F.

    2015-01-01

    Despite many claims of functional reorganization following tumour surgery, empirical studies that investigate changes in functional activation patterns are rare. This study investigates whether functional recovery following surgical treatment in patients with a low-grade glioma in the left hemispher

  7. Cortical Reorganization in Dyslexic Children after Phonological Training: Evidence from Early Evoked Potentials

    Science.gov (United States)

    Spironelli, Chiara; Penolazzi, Barbara; Vio, Claudio; Angrilli, Alessandro

    2010-01-01

    Brain plasticity was investigated in 14 Italian children affected by developmental dyslexia after 6 months of phonological training. The means used to measure language reorganization was the recognition potential, an early wave, also called N150, elicited by automatic word recognition. This component peaks over the left temporo-occipital cortex…

  8. 75 FR 26198 - Foreign-Trade Zone 152 - Burns Harbor, Indiana, Application for Reorganization under Alternative...

    Science.gov (United States)

    2010-05-11

    ... Foreign-Trade Zones Board Foreign-Trade Zone 152 - Burns Harbor, Indiana, Application for Reorganization...-purpose zone currently consists of six sites in the Burns Harbor/Gary, Indiana area: Site 1: (533,288 sq...); Site 2: (441 acres) within the Port of Indiana/Burns International Harbor, Burns Harbor (Porter...

  9. 78 FR 60695 - Regulatory Reorganization; Administrative Changes to Regulations Due to the Consolidation of the...

    Science.gov (United States)

    2013-10-02

    ... Fiscal Service Bureau of the Fiscal Service 31 CFR Chapter II, Parts 202-391 RIN 1510-AB31 Regulatory Reorganization; Administrative Changes to Regulations Due to the Consolidation of the Financial Management Service and the Bureau of the Public Debt Into the Bureau of the Fiscal Service AGENCY: Bureau of...

  10. 75 FR 61051 - Reorganization of Title 30, Code of Federal Regulations

    Science.gov (United States)

    2010-10-04

    ... reorganization, the Secretary renamed MMS's Minerals Revenue Management Program (MRM) the Office of Natural... of Natural Resources Revenue (ONRR); the Bureau of Ocean Energy Management (BOEM); and the Bureau of.... Part 243--Suspensions Pending Appeal and Bonding--Minerals Revenue Management, which becomes part...

  11. 76 FR 38555 - Reorganization of Title 30, Code of Federal Regulations

    Science.gov (United States)

    2011-07-01

    ... that the Minerals Revenue Management Program (MRM) of the Bureau of Ocean Energy Management, Regulation... Bureau of Ocean Energy Management, Regulation and Enforcement 30 CFR Part 250 Office of Natural Resources Revenue 30 CFR Parts 1204, 1206, 1218, 1241, and 1290 RIN 1012-AA06 Reorganization of Title 30, Code...

  12. 78 FR 24154 - Notice of Availability of a National Animal Health Laboratory Network Reorganization Concept Paper

    Science.gov (United States)

    2013-04-24

    ... Network Reorganization Concept Paper AGENCY: Animal and Plant Health Inspection Service, USDA. ACTION... Plant Health Inspection Service is making available a concept paper that describes a revised structure... paper we are making available for comment presents a structure we believe will give the NAHLN increased...

  13. [The reorganization of the schema and body image of the amputee].

    Science.gov (United States)

    Giorgi, Ines; Gobba, Omar; Manera, Marina

    2015-01-01

    The paper deals with the psychological problems related to the amputee's experience. The stages of the reorganization of the body image and the problems that may arise, are described. In this process the phantom limb syndrome represents an important paradigm for study and reflection.

  14. Language localization in cases of left temporal lobe arachnoid cyst : Evidence against interhemispheric reorganization

    NARCIS (Netherlands)

    Stowe, LA; Go, KG; Pruim, J; den Dunnen, W; Meiners, LC; Paans, AMJ

    2000-01-01

    We investigated whether left-hemisphere arachnoid cysts lead to reorganization of the language function using PET. A group analysis demonstrated that patients showed no more right-hemisphere activation than a matched control group. Several patients had clear language localizations in the left hemisp

  15. 26 CFR 1.1502-30 - Stock basis after certain triangular reorganizations.

    Science.gov (United States)

    2010-04-01

    ... 26 Internal Revenue 12 2010-04-01 2010-04-01 false Stock basis after certain triangular... (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES Basis, Stock Ownership, and Earnings and Profits Rules § 1.1502-30 Stock basis after certain triangular reorganizations. (a) Scope. This section provides...

  16. Large impact of reorganization energy on photovoltaic conversion due to interfacial charge-transfer transitions.

    Science.gov (United States)

    Fujisawa, Jun-ichi

    2015-05-14

    Interfacial charge-transfer (ICT) transitions are expected to be a novel charge-separation mechanism for efficient photovoltaic conversion featuring one-step charge separation without energy loss. Photovoltaic conversion due to ICT transitions has been investigated using several TiO2-organic hybrid materials that show organic-to-inorganic ICT transitions in the visible region. In applications of ICT transitions to photovoltaic conversion, there is a significant problem that rapid carrier recombination is caused by organic-inorganic electronic coupling that is necessary for the ICT transitions. In order to solve this problem, in this work, I have theoretically studied light-to-current conversions due to the ICT transitions on the basis of the Marcus theory with density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations. An apparent correlation between the reported incident photon-to-current conversion efficiencies (IPCE) and calculated reorganization energies was clearly found, in which the IPCE increases with decreasing the reorganization energy consistent with the Marcus theory in the inverted region. This activation-energy dependence was systematically explained by the equation formulated by the Marcus theory based on a simple excited-state kinetic scheme. This result indicates that the reduction of the reorganization energy can suppress the carrier recombination and enhance the IPCE. The reorganization energy is predominantly governed by the structural change in the chemical-adsorption moiety between the ground and ICT excited states. This work provides crucial knowledge for efficient photovoltaic conversion due to ICT transitions.

  17. Sleep EEG Changes during Adolescence: An Index of a Fundamental Brain Reorganization

    Science.gov (United States)

    Feinberg, Irwin; Campbell, Ian G.

    2010-01-01

    Delta (1-4 Hz) EEG power in non-rapid eye movement (NREM) sleep declines massively during adolescence. This observation stimulated the hypothesis that during adolescence the human brain undergoes an extensive reorganization driven by synaptic elimination. The parallel declines in synaptic density, delta wave amplitude and cortical metabolic rate…

  18. Stimulation through Simulation? Motor Imagery and Functional Reorganization in Hemiplegic Stroke Patients

    Science.gov (United States)

    Johnson-Frey, Scott H.

    2004-01-01

    A key factor influencing reorganization of function in damaged neural networks of the adult brain is stimulation. How to stimulate motor areas of patients with paralyses is a formidable challenge. One possibility is to use internal movement simulations, or motor imagery, as an alternative to conventional therapeutic interventions that require…

  19. 7 CFR 4290.470 - Prior approval of merger, consolidation, or reorganization of RBIC.

    Science.gov (United States)

    2010-01-01

    ... BUSINESS INVESTMENT COMPANY (âRBICâ) PROGRAM Changes in Ownership, Structure, or Control Change in Structure of Rbic § 4290.470 Prior approval of merger, consolidation, or reorganization of RBIC. You may not merge, consolidate, change form of organization (corporation, limited liability company, or...

  20. Landscape reorganization under changing climatic forcing: Results from an experimental landscape

    Science.gov (United States)

    Singh, Arvind; Reinhardt, Liam; Foufoula-Georgiou, Efi

    2015-06-01

    Understanding how landscapes respond to climate dynamics in terms of macroscale (average topographic features) and microscale (landform reorganization) is of interest both for deciphering past climates from today's landscapes and for predicting future landscapes in view of recent climatic trends. Although several studies have addressed macro-scale response, only a few have focused on quantifying smaller-scale basin reorganization. To that goal, a series of controlled laboratory experiments were conducted where a self-organized complete drainage network emerged under constant precipitation and uplift dynamics. Once steady state was achieved, the landscape was subjected to a fivefold increase in precipitation (transient state). Throughout the evolution, high-resolution spatiotemporal topographic data in the form of digital elevation models were collected. The steady state landscape was shown to possess three distinct geomorphic regimes (unchannelized hillslopes, debris-dominated channels, and fluvially dominated channels). During transient state, landscape reorganization was observed to be driven by hillslopes via accelerated erosion, ridge lowering, channel widening, and reduction of basin relief as opposed to channel base-level reduction. Quantitative metrics on which these conclusions were based included slope-area curve, correlation analysis of spatial and temporal elevation increments, and wavelet spectral analysis of the evolving landscapes. Our results highlight that landscape reorganization in response to increased precipitation seems to follow "an arrow of scale": major elevation change initiates at the hillslope scale driving erosional regime change at intermediate scales and further cascading to geomorphic changes at the channel scale as time evolves.

  1. Reorganization of Elementary Educational System and Commutation of Children to Collective Commune Schools.

    Science.gov (United States)

    Palonka, Krystyna Maria

    Between 1973-1979, the elementary educational system in rural areas of Poland has been reorganized into a system of collective commune schools; students commute or are bused to the schools. Since September 1973, 944 new collective commune schools have been set up. A study of the data indicates that the process of setting up collective commune…

  2. Thermodynamics for nonequilibrium solvation and numerical evaluation of solvent reorganization energy

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    This work presents a thermodynamic method for treating nonequilibrium solvation. By imposing an extra electric field onto the nonequilibrium solvation system, a virtual constrained equilibrium state is prepared. In this way, the free energy difference between the real nonequilibrium state and the con-strained equilibrium one is simply the potential energy of the nonequilibrium polarization in the extra electronic field, according to thermodynamics. Further, new expressions of nonequilibrium solvation energy and solvent reorganization energy have been formulated. Analysis shows that the present formulations will give a value of reorganization energy about one half of the traditional Marcus theory in polar solvents, thus the explanation on why the traditional theory tends to overestimate this quantity has been found out. For the purpose of numerical determination of solvent reorganization energy, we have modified Gamess program on the basis of dielectric polarizable continuum model. Applying the procedure to the well-investigated intramolecular electron transfer in biphenyl-androstane-naphthyl and biphenyl-androstane-phenanthryl systems, the numerical results of solvent reorganization energy have been found to be in good agreement with the experimental fittings.

  3. Photoinduced Reorganization of Motor-Doped Chiral Liquid Crystals : Bridging Molecular Isomerization and Texture Rotation

    NARCIS (Netherlands)

    Bosco, Alessandro; Jongejan, Mahthild G. M.; Eelkema, Rienk; Katsonis, Nathalie; Lacaze, Ernmanuelle; Ferrarini, Alberta; Feringa, Ben L.; Lacaze, Emmanuelle

    2008-01-01

    We recently reported that the photoisomerization of molecular motors used as chiral dopants in a cholesteric liquid crystal film induces a rotational reorganization which can be observed by optical microscopy and produces the motion of microscopic objects placed on top of the film (Feringa, B. L.;

  4. Reorganization of Functional Connectivity as a Correlate of Cognitive Recovery in Acquired Brain Injury

    Science.gov (United States)

    Castellanos, Nazareth P.; Paul, Nuria; Ordonez, Victoria E.; Demuynck, Olivier; Bajo, Ricardo; Campo, Pablo; Bilbao, Alvaro; Ortiz, Tomas; del-Pozo, Francisco; Maestu, Fernando

    2010-01-01

    Cognitive processes require a functional interaction between specialized multiple, local and remote brain regions. Although these interactions can be strongly altered by an acquired brain injury, brain plasticity allows network reorganization to be principally responsible for recovery. The present work evaluates the impact of brain injury on…

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

    Science.gov (United States)

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

    2017-03-01

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

  6. Parietal operculum and motor cortex activities predict motor recovery in moderate to severe stroke

    Directory of Open Access Journals (Sweden)

    Firdaus Fabrice Hannanu

    2017-01-01

    In subacute stroke, fMRI brain activity related to passive movement measured in a sensorimotor network defined by activity during voluntary movement predicted motor recovery better than baseline motor-FMS alone. Furthermore, fMRI sensorimotor network activity measures considered alone allowed excellent clinical recovery prediction and may provide reliable biomarkers for assessing new therapies in clinical trial contexts. Our findings suggest that neural reorganization related to motor recovery from moderate to severe stroke results from balanced changes in ipsilesional MI (BA4a and a set of phylogenetically more archaic sensorimotor regions in the ventral sensorimotor trend, in which OP1 and OP4 processes may complement the ipsilesional dorsal motor cortex in achieving compensatory sensorimotor recovery.

  7. Basal forebrain cholinergic input is not essential for lesion-induced plasticity in mature auditory cortex.

    Science.gov (United States)

    Kamke, Marc R; Brown, Mel; Irvine, Dexter R F

    2005-11-23

    The putative role of the basal forebrain cholinergic system in mediating lesion-induced plasticity in topographic cortical representations was investigated. Cholinergic immunolesions were combined with unilateral restricted cochlear lesions in adult cats, demonstrating the consequence of cholinergic depletion on lesion-induced plasticity in primary auditory cortex (AI). Immunolesions almost eliminated the cholinergic input to AI, while cochlear lesions produced broad high-frequency hearing losses. The results demonstrate that the near elimination of cholinergic input does not disrupt reorganization of the tonotopic representation of the lesioned (contralateral) cochlea in AI and does not affect the normal representation of the unlesioned (ipsilateral) cochlea. It is concluded that cholinergic basal forebrain input to AI is not essential for the occurrence of lesion-induced plasticity in AI.

  8. Unresolved Trauma in Mothers: Intergenerational Effects and the Role of Reorganization

    Directory of Open Access Journals (Sweden)

    Udita eIyengar

    2014-09-01

    Full Text Available A mother’s unresolved trauma may interfere with her ability to sensitively respond to her infant, thus affecting the development of attachment in her own child, and potentially contributing to the intergenerational transmission of trauma. One novel construct within the Dynamic Maturational Model of Attachment and Adaptation (DMM coding of the Adult Attachment Interview (AAI is reorganization, a process whereby speakers are actively changing their understanding of past and present experiences and moving toward attachment security. We conducted a study of mothers with unresolved trauma, exploring their own attachment classification, attachment outcomes of their children, and the potential effects of reorganization on child attachment. Forty-seven first-time mothers participated in the AAI during pregnancy, and returned with their child at 11 months to assess child attachment using the Strange Situation Procedure. Mothers with and without unresolved trauma were compared. We found that mothers with unresolved trauma had insecure attachment themselves and were more likely to have infants with insecure attachment. However, the one exception was that all of the mothers with unresolved trauma who were reorganizing towards secure attachment had infants with secure attachment. These preliminary findings suggest that mothers who are reorganizing may be able to more sensitively respond to their child’s cues, contributing to the development of secure attachment. While our results need to be replicated in a larger cohort, this study is the first to explore the construct of reorganization and its potential relationship with child attachment. If confirmed in future studies, it may provide clinical insight into the intergenerational transmission of insecure attachment within the context of unresolved trauma.

  9. Neural network remodeling underlying motor map reorganization induced by rehabilitative training after ischemic stroke.

    Science.gov (United States)

    Okabe, Naohiko; Shiromoto, Takashi; Himi, Naoyuki; Lu, Feng; Maruyama-Nakamura, Emi; Narita, Kazuhiko; Iwachidou, Nobuhisa; Yagita, Yoshiki; Miyamoto, Osamu

    2016-12-17

    Motor map reorganization is believed to be one mechanism underlying rehabilitation-induced functional recovery. Although the ipsilesional secondary motor area has been known to reorganize motor maps and contribute to rehabilitation-induced functional recovery, it is unknown how the secondary motor area is reorganized by rehabilitative training. In the present study, using skilled forelimb reaching tasks, we investigated neural network remodeling in the rat rostral forelimb area (RFA) of the secondary motor area during 4weeks of rehabilitative training. Following photothrombotic stroke in the caudal forelimb area (CFA), rehabilitative training led to task-specific recovery and motor map reorganization in the RFA. A second injury to the RFA resulted in reappearance of motor deficits. Further, when both the CFA and RFA were destroyed simultaneously, rehabilitative training no longer improved task-specific recovery. In neural tracer studies, although rehabilitative training did not alter neural projection to the RFA from other brain areas, rehabilitative training increased neural projection from the RFA to the lower spinal cord, which innervates the muscles in the forelimb. Double retrograde tracer studies revealed that rehabilitative training increased the neurons projecting from the RFA to both the upper cervical cord, which innervates the muscles in the neck, trunk, and part of the proximal forelimb, and the lower cervical cord. These results suggest that neurons projecting to the upper cervical cord provide new connections to the denervated forelimb area of the spinal cord, and these new connections may contribute to rehabilitation-induced task-specific recovery and motor map reorganization in the secondary motor area.

  10. [Impact of reorganization of the Hungarian system of intensive care units in 2012].

    Science.gov (United States)

    Gresz, Miklós

    2016-10-01

    In 2012, the Hungarian system of intensive care units was reorganized. During this process, multidisciplinary units were separated from observation units. The author analysed certain indicators of the remaining intensive care units. The study was based on reports of National Health Insurance Fund between 2000 and 2015. After reorganization the number of the multidisciplinary intensive care units decreased by 20% and the number of beds decreased by 10%. Due to the reorganization, both the case-mix index and the days of mechanical ventilation increased significantly in the multidisciplinary intensive care units. In 2000, 12% of the patients were discharged directly from the intensive care units to home, but by 2014, this figure decreased to 3%. The bed-occupancy rate of the intensive care units did not change fundamentally and it was under 80% in each calendar day. In addition to the ICD leading groups I and J, the rate of "Sine morbo" (U9990) diagnosis decreased from 0.7% to 0.2%. Similarly, the ratio of R group which describes only symptoms decreased from 1.7% to 1.1%. In contrast, between the interventions the number of fluid and electrolyte imbalances and respiratory monitoring showed more than twofold increase. These results suggest that the reorganization was effective. The activity of the intensive care units has improved significantly, without disturbing patient care. The author suggests further analysis on the basis of the same criteria for other departments and the consistent continuation of the reorganization process. Orv. Hetil., 2016, 157(44), 1757-1761.

  11. Increased BOLD variability in the parietal cortex and enhanced parieto-occipital connectivity during tactile perception in congenitally blind individuals.

    Science.gov (United States)

    Leo, Andrea; Bernardi, Giulio; Handjaras, Giacomo; Bonino, Daniela; Ricciardi, Emiliano; Pietrini, Pietro

    2012-01-01

    Previous studies in early blind individuals posited a possible role of parieto-occipital connections in conveying nonvisual information to the visual occipital cortex. As a consequence of blindness, parietal areas would thus become able to integrate a greater amount of multimodal information than in sighted individuals. To verify this hypothesis, we compared fMRI-measured BOLD signal temporal variability, an index of efficiency in functional information integration, in congenitally blind and sighted individuals during tactile spatial discrimination and motion perception tasks. In both tasks, the BOLD variability analysis revealed many cortical regions with a significantly greater variability in the blind as compared to sighted individuals, with an overlapping cluster located in the left inferior parietal/anterior intraparietal cortex. A functional connectivity analysis using this region as seed showed stronger correlations in both tasks with occipital areas in the blind as compared to sighted individuals. As BOLD variability reflects neural integration and processing efficiency, these cross-modal plastic changes in the parietal cortex, even if described in a limited sample, reinforce the hypothesis that this region may play an important role in processing nonvisual information in blind subjects and act as a hub in the cortico-cortical pathway from somatosensory cortex to the reorganized occipital areas.

  12. Increased BOLD Variability in the Parietal Cortex and Enhanced Parieto-Occipital Connectivity during Tactile Perception in Congenitally Blind Individuals

    Directory of Open Access Journals (Sweden)

    Andrea Leo

    2012-01-01

    Full Text Available Previous studies in early blind individuals posited a possible role of parieto-occipital connections in conveying nonvisual information to the visual occipital cortex. As a consequence of blindness, parietal areas would thus become able to integrate a greater amount of multimodal information than in sighted individuals. To verify this hypothesis, we compared fMRI-measured BOLD signal temporal variability, an index of efficiency in functional information integration, in congenitally blind and sighted individuals during tactile spatial discrimination and motion perception tasks. In both tasks, the BOLD variability analysis revealed many cortical regions with a significantly greater variability in the blind as compared to sighted individuals, with an overlapping cluster located in the left inferior parietal/anterior intraparietal cortex. A functional connectivity analysis using this region as seed showed stronger correlations in both tasks with occipital areas in the blind as compared to sighted individuals. As BOLD variability reflects neural integration and processing efficiency, these cross-modal plastic changes in the parietal cortex, even if described in a limited sample, reinforce the hypothesis that this region may play an important role in processing nonvisual information in blind subjects and act as a hub in the cortico-cortical pathway from somatosensory cortex to the reorganized occipital areas.

  13. Brain reorganization as a function of walking experience in 12-month-old infants: implications for the development of manual laterality.

    Science.gov (United States)

    Corbetta, Daniela; Friedman, Denise R; Bell, Martha Ann

    2014-01-01

    Hand preference in infancy is marked by many developmental shifts in hand use and arm coupling as infants reach for and manipulate objects. Research has linked these early shifts in hand use to the emergence of fundamental postural-locomotor milestones. Specifically, it was found that bimanual reaching declines when infants learn to sit; increases if infants begin to scoot in a sitting posture; declines when infants begin to crawl on hands and knees; and increases again when infants start walking upright. Why such pattern fluctuations during periods of postural-locomotor learning? One proposed hypothesis is that arm use practiced for the specific purpose of controlling posture and achieving locomotion transfers to reaching via brain functional reorganization. There has been scientific support for functional cortical reorganization and change in neural connectivity in response to motor practice in adults and animals, and as a function of crawling experience in human infants. In this research, we examined whether changes in neural connectivity also occurred as infants coupled their arms when learning to walk and whether such coupling mapped onto reaching laterality. Electroencephalogram (EEG) coherence data were collected from 43 12-month-old infants with varied levels of walking experience. EEG was recorded during quiet, attentive baseline. Walking proficiency was laboratory assessed and reaching responses were captured using small toys presented at mid-line while infants were sitting. Results revealed greater EEG coherence at homologous prefrontal/central scalp locations for the novice walkers compared to the prewalkers or more experienced walkers. In addition, reaching laterality was low in prewalkers and early walkers but high in experienced walkers. These results are consistent with the interpretation that arm coupling practiced during early walking transferred to reaching via brain functional reorganization, leading to the observed developmental changes in

  14. Brain reorganization as a function of walking experience in 12 month-old infants: Implications for the development of manual laterality

    Directory of Open Access Journals (Sweden)

    Daniela eCorbetta

    2014-03-01

    Full Text Available Hand preference in infancy is marked by many developmental shifts in hand use and arm coupling as infants reach for and manipulate objects. Research has linked these early shifts in hand use to the emergence of fundamental postural-locomotor milestones. Specifically, it was found that bimanual reaching declines when infants learn to sit; increases if infants begin to scoot in a sitting posture; declines when infants begin to crawl on hands-and-knees; and increases again when infants start walking upright. Why such pattern fluctuations during periods of postural-locomotor learning? One proposed hypothesis is that arm use practiced for the specific purpose of controlling posture and achieving locomotion transfers to reaching via brain functional reorganization. There has been scientific support for functional cortical reorganization and change in neural connectivity in response to motor practice in adults and animals, and as a function of crawling experience in human infants. In this research, we examined whether changes in neural connectivity also occurred as infants coupled their arms when learning to walk and whether such coupling mapped onto reaching laterality. EEG coherence data were collected from 43 12-month-olds infants with varied levels of walking experience. EEG was recorded during quiet, attentive baseline. Walking proficiency was laboratory assessed and reaching responses were captured using small toys presented at midline while infants were sitting. Results revealed greater EEG coherence at homologous prefrontal/central scalp locations for the novice walkers compared to the pre-walkers or more experienced walkers. In addition, reaching laterality was low in pre-walkers and early walkers, but high in experienced walkers. These results are consistent with the interpretation that arm coupling practiced during early walking transferred to reaching via brain functional reorganization, leading to the observed developmental changes in

  15. Triterpenoid saponins from Cortex Albiziae

    OpenAIRE

    Zou, Kun; Zhao, Yuying

    2004-01-01

    Cortex Albiziae, the dried stem bark of a leguminous plant, Albizia julibrissin Durazz, was specified in Chinese Pharmacopoeia (1995 edit.) as a traditional Chinese medicine to be used.to relieve melancholia and uneasiness of body and mind, to invigorate the circulation of blood and subside a swelling. In a course of our quality assessment of traditional Chinese medicines, the n-BuOH soluble part of 95% EtOH extracts from the stem barks of Albizia julibrissin was subjected to a series of sol...

  16. Recruitment of the prefrontal cortex and cerebellum in Parkinsonian rats following skilled aerobic exercise.

    Science.gov (United States)

    Wang, Zhuo; Guo, Yumei; Myers, Kalisa G; Heintz, Ryan; Holschneider, Daniel P

    2015-05-01

    Exercise modality and complexity play a key role in determining neurorehabilitative outcome in Parkinson's disease (PD). Exercise training (ET) that incorporates both motor skill training and aerobic exercise has been proposed to synergistically improve cognitive and automatic components of motor control in PD patients. Here we introduced such a skilled aerobic ET paradigm in a rat model of dopaminergic deafferentation. Rats with bilateral, intra-striatal 6-hydroxydopamine lesions were exposed to forced ET for 4weeks, either on a simple running wheel (non-skilled aerobic exercise, NSAE) or on a complex wheel with irregularly spaced rungs (skilled aerobic exercise, SAE). Cerebral perfusion was mapped during horizontal treadmill walking or at rest using [(14)C]-iodoantipyrine 1week after the completion of ET. Regional cerebral blood flow (rCBF) was quantified by autoradiography and analyzed in 3-dimensionally reconstructed brains by statistical parametric mapping. SAE compared to NSAE resulted in equal or greater recovery in motor deficits, as well as greater increases in rCBF during walking in the prelimbic area of the prefrontal cortex, broad areas of the somatosensory cortex, and the cerebellum. NSAE compared to SAE animals showed greater activation in the dorsal caudate-putamen and dorsal hippocampus. Seed correlation analysis revealed enhanced functional connectivity in SAE compared to NSAE animals between the prelimbic cortex and motor areas, as well as altered functional connectivity between midline cerebellum and sensorimotor regions. Our study provides the first evidence for functional brain reorganization following skilled aerobic exercise in Parkinsonian rats, and suggests that SAE compared to NSAE results in enhancement of prefrontal cortex- and cerebellum-mediated control of motor function.

  17. Brain reorganization following intervention in children with congenital hemiplegia: a systematic review.

    Science.gov (United States)

    Inguaggiato, E; Sgandurra, G; Perazza, S; Guzzetta, A; Cioni, G

    2013-01-01

    Noninvasive rehabilitation strategies for children with unilateral cerebral palsy are routinely used to improve hand motor function, activity, and participation. Nevertheless, the studies exploring their effects on brain structure and function are very scarce. Recently, structural neuroplasticity was demonstrated in adult poststroke patients, in response to neurorehabilitation. Our purpose is to review current evidence on the effects of noninvasive intervention strategies on brain structure or function, in children with unilateral cerebral palsy. The main literature databases were searched up to October 2013. We included studies where the effects of upper limb training were evaluated at neurofunctional and/or neurostructural levels. Only seven studies met our selection criteria; selected studies were case series, six using the intervention of the constraint-induced movement therapy (CIMT) and one used virtual reality therapy (VR). CIMT and VR seem to produce measurable neuroplastic changes in sensorimotor cortex associated with enhancement of motor skills in the affected limb. However, the level of evidence is limited, due to methodological weaknesses and small sample sizes of available studies. Well-designed and larger experimental studies, in particular RCTs, are needed to strengthen the generalizability of the findings and to better understand the mechanism of intervention-related brain plasticity in children with brain injury.

  18. Brain Reorganization following Intervention in Children with Congenital Hemiplegia: A Systematic Review

    Directory of Open Access Journals (Sweden)

    E. Inguaggiato

    2013-01-01

    Full Text Available Noninvasive rehabilitation strategies for children with unilateral cerebral palsy are routinely used to improve hand motor function, activity, and participation. Nevertheless, the studies exploring their effects on brain structure and function are very scarce. Recently, structural neuroplasticity was demonstrated in adult poststroke patients, in response to neurorehabilitation. Our purpose is to review current evidence on the effects of noninvasive intervention strategies on brain structure or function, in children with unilateral cerebral palsy. The main literature databases were searched up to October 2013. We included studies where the effects of upper limb training were evaluated at neurofunctional and/or neurostructural levels. Only seven studies met our selection criteria; selected studies were case series, six using the intervention of the constraint-induced movement therapy (CIMT and one used virtual reality therapy (VR. CIMT and VR seem to produce measurable neuroplastic changes in sensorimotor cortex associated with enhancement of motor skills in the affected limb. However, the level of evidence is limited, due to methodological weaknesses and small sample sizes of available studies. Well-designed and larger experimental studies, in particular RCTs, are needed to strengthen the generalizability of the findings and to better understand the mechanism of intervention-related brain plasticity in children with brain injury.

  19. Monkey brain cortex imaging by photoacoustic tomography.

    Science.gov (United States)

    Yang, Xinmai; Wang, Lihong V

    2008-01-01

    Photoacoustic tomography (PAT) is applied to image the brain cortex of a monkey through the intact scalp and skull ex vivo. The reconstructed PAT image shows the major blood vessels on the monkey brain cortex. For comparison, the brain cortex is imaged without the scalp, and then imaged again without the scalp and skull. Ultrasound attenuation through the skull is also measured at various incidence angles. This study demonstrates that PAT of the brain cortex is capable of surviving the ultrasound signal attenuation and distortion caused by a relatively thick skull.

  20. Conformational Reorganization Coupled to the Ionization of Internal Lys Residues in Proteins.

    Science.gov (United States)

    Richman, Daniel E; Majumdar, Ananya; García-Moreno E, Bertrand

    2015-09-29

    Ionizable groups buried in the hydrophobic interior of proteins are essential for energy transduction and catalysis. Because the protein interior is usually neither as polar nor as polarizable as water, these groups tend to have anomalous pKa values, and their ionization tends to be coupled to conformational reorganization. To elucidate mechanisms of energy transduction in proteins, it is necessary to understand the structural determinants of the pKa values of these buried groups, including the range and character of the conformational reorganization that the ionization of these buried groups can elicit. The L25K and L125K variants of staphylococcal nuclease (SNase) were used to characterize the diverse types of structural reorganization that can be promoted by the ionization of buried groups. NMR relaxation dispersion and ZZ-exchange experiments were used to identify the locations and measure the time scales and extent of pH-dependent conformational exchange in these two proteins. The buried Lys-25 and Lys-125 residues titrate with pKa of 6.3 and 6.2, respectively. The L25K protein fluctuates between the native state and an ensemble of locally unfolded states on the 400 μs to 7 ms time scale. On the 100 to 500 ms time scale the native state exchanges with a subglobally unfolded state in which the β-barrel is partially reorganized. The equilibrium between the native state and this alternative state is highly pH dependent; at pH values below the pKa of Lys-25 the state with the partially reorganized β-barrel is the dominant state. In contrast, the L125K protein only exhibited pH-independent fluctuation in the microsecond to millisecond time scale in the region near Lys-125. The study illustrates how diverse and how localized the coupling between conformational reorganization and ionization of buried groups can be. The pH-sensitive exchange between the fully native and subglobally or locally unfolded states in time scales well into hundreds of milliseconds will

  1. Prefrontal cortex glutamate and extraversion.

    Science.gov (United States)

    Grimm, Simone; Schubert, Florian; Jaedke, Maren; Gallinat, Jürgen; Bajbouj, Malek

    2012-10-01

    Extraversion is considered one of the core traits of personality. Low extraversion has been associated with increased vulnerability to affective and anxiety disorders. Brain imaging studies have linked extraversion, approach behaviour and the production of positive emotional states to the dorsolateral prefrontal cortex (DLPFC) and glutamatergic neurotransmission. However, the relationship between extraversion and glutamate in the DLPFC has not been investigated so far. In order to address this issue, absolute glutamate concentrations in the DLPFC and the visual cortex as a control region were measured by 3-Tesla proton magnetic resonance spectroscopy (1H-MRS) in 29 subjects with high and low extraversion. We found increased glutamate levels in the DLPFC of introverts as compared with extraverts. The increased glutamate concentration was specific for the DLPFC and negatively associated with state anxiety. Although preliminary, results indicate altered top-down control of DLPFC due to reduced glutamate concentration as a function of extraversion. Glutamate measurement with 1H-MRS may facilitate the understanding of biological underpinnings of personality traits and psychiatric diseases associated with dysfunctions in approach behaviour and the production of positive emotional states.

  2. Effects of diazepam and levodopa single doses on motor cortex plasticity modulation in healthy human subjects: A TMS study

    Directory of Open Access Journals (Sweden)

    Ilić Nela V.

    2012-01-01

    Full Text Available Introduction. Administration of pharmacological agents with specific actions on neurotransmitter systems is a powerful driver of functional cortical reorganization. Plastic reorganization of the motor cortex in humans studies by the use of non-invasive stimulation protocols, which mimic the Hebbian model of associative plasticity. Objective. Aiming to explore pharmacological modulation on human motor cortex plasticity, we tested healthy subjects after each dosage of diazepam, levodopa i placebo administration, using paired associative stimulation protocol (PAS that induce fenomena similar to a long-term potentiation and depression, as defined on the synaptic level. Methods. We analyzed effects of benzodiazepines (10 mg, levodopa (200 mg and placebo on PAS protocol in 14 healthy volunteers, using a double-blind placebo-controlled study design. PAS consisted of electrical stimuli pairs at n.medianus and magnetic pulses over the scalp (transcranial magnetic stimulation in precisely defined intervals (ISI was 10 and 25 ms for a total of about 15 minutes (200 pairs. MEP amplitudes before and after (0, 10, 20 and 30 minutes later interventional protocols were compared. Results. When protocols were applied with placebo depending on ISI (10 ms - inhibitory, 25 ms - facilitatory effects, MEP amplitudes decreased or increased, while values in the postinterventional period (0, 10, 20 and 30 min were compared with initial values before the use of SAS. The use of benzodiazepines caused the occlusion of LTP-like effect, in contrast to amplification effects recorded after the administration of levodopa. With respect to the LTD-like protocol, the reverse was true (ANOVA for repeat measurements p<0.001. Conclusion. Administration of GABA-ergic agonist diazepam interferes with the induction of associative plasticity in the motor cortex of healthy individuals, as opposed to the use of levodopa, which stimulates these processes. The observed effects point at a

  3. The influence of psychological flexibility on work redesign: mediated moderation of a work reorganization intervention.

    Science.gov (United States)

    Bond, Frank W; Flaxman, Paul E; Bunce, David

    2008-05-01

    This quasi-experiment tested the extent to which an individual characteristic, psychological flexibility, moderated the effects of a control-enhancing work reorganization intervention in a call center. Results indicated that, compared with a control group, this intervention produced improvements in mental health and absence rates, particularly for individuals with higher levels of psychological flexibility. Findings also showed that these moderated intervention effects were mediated by job control. Specifically, the intervention enhanced perceptions of job control, and hence its outcomes, for the people who received it, especially for those who had greater psychological flexibility. Discussion highlights the benefits of understanding the processes (e.g., mediators, moderators, and mediated moderators) involved in work reorganization interventions.

  4. Effect of a reorganized after-hours family practice service on frequent attenders

    DEFF Research Database (Denmark)

    Vedsted, Peter; Olesen, Frede

    1999-01-01

    of this reorganization on the use of services by frequent attenders (FAs). METHODS: From 1990 to 1994, methods of contact and annual costs per attender were analyzed in an ecological time-trend study based on aggregated administrative data collected from the database of the Public Health Insurance, Aarhus County......BACKGROUND AND OBJECTIVES: A governmental reorganization of the after-hours general practice service in Denmark was launched in January 1992. The biggest change was the introduction of mandatory county-wide telephone triage systems staffed by general practitioners. This study assesses the effect......, Denmark (600,000 inhabitants). The study only included attenders ages 18 and over. FAs were defined as the group that, within each calendar year (12 months), had 4 or more contacts with the after-hours family practice service. RESULTS: FAs made up 9.5% of the attenders and accounted for more than 40...

  5. Tuning Reactivity and Electronic Properties through Ligand Reorganization within a Cerium Heterobimetallic Framework

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, Jerome R.; Gordon, Zachary; Booth, Corwin H.; Carroll, Patrick J.; Walsh, Patrick J.; Schelter, Eric J.

    2014-06-24

    Cerium compounds have played vital roles in organic, inorganic, and materials chemistry due to their reversible redox chemistry between trivalent and tetravalent oxidation states. However, attempts to rationally access molecular cerium complexes in both oxidation states have been frustrated by unpredictable reactivity in cerium(III) oxidation chemistry. Such oxidation reactions are limited by steric saturation at the metal ion, which can result in high energy activation barriers for electron transfer. An alternative approach has been realized using a rare earth/alkali metal/1,1'-BINOLate (REMB) heterobimetallic framework, which uses redox-inactive metals within the secondary coordination sphere to control ligand reorganization. The rational syntheses of functionalized cerium(IV) products and a mechanistic examination of the role of ligand reorganization in cerium(III) oxidation are presented.

  6. A Systems Survey of Progressive Host-Cell Reorganization during Rotavirus Infection.

    Science.gov (United States)

    Green, Victoria A; Pelkmans, Lucas

    2016-07-13

    Pathogen invasion is often accompanied by widespread alterations in cellular physiology, which reflects the hijacking of host factors and processes for pathogen entry and replication. Although genetic perturbation screens have revealed the complexity of host factors involved for numerous pathogens, it has remained challenging to temporally define the progression of events in host cell reorganization during infection. We combine high-confidence genome-scale RNAi screening of host factors required for rotavirus infection in human intestinal cells with an innovative approach to infer the trajectory of virus infection from fixed cell populations. This approach reveals a comprehensive network of host cellular processes involved in rotavirus infection and implicates AMPK in initiating the development of a rotavirus-permissive environment. Our work provides a powerful approach that can be generalized to order complex host cellular requirements along a trajectory of cellular reorganization during pathogen invasion.

  7. Designed azurins show lower reorganization free energies for intraprotein electron transfer

    DEFF Research Database (Denmark)

    Farver, Ole; Marshall, Nicholas M; Wherland, Scot

    2013-01-01

    and to enable potential applications in different energy conversion systems. Herein we report studies of the intramolecular ET from pulse radiolytically produced disulfide radicals to Cu(II) in rationally designed azurin mutants. In these mutants, the copper coordination sphere has been fine-tuned to span...... a wide range of reduction potentials while leaving the metal binding site effectively undisrupted. We find that the reorganization free energies of ET within the mutants are indeed lower than that of WT azurin, increasing the intramolecular ET rate constants almost 10-fold: changes that are correlated...... with increased flexibility of their copper sites. Moreover, the lower reorganization free energy results in the ET rate constants reaching a maximum value at higher driving forces, as predicted by the Marcus theory....

  8. Symmetrization in jellyfish: reorganization to regain function, and not lost parts.

    Science.gov (United States)

    Abrams, Michael J; Goentoro, Lea

    2016-02-01

    We recently reported a previously unidentified strategy of self-repair in the moon jellyfish Aurelia aurita. Rather than regenerating lost parts, juvenile Aurelia reorganize remaining parts to regain essential body symmetry. This process that we called symmetrization is rapid and frequent, and is not driven by cell proliferation or cell death. Instead, the swimming machinery generates mechanical forces that drive symmetrization. We found evidence for symmetrization across three other species of jellyfish (Chrysaora pacifica, Mastigias sp., and Cotylorhiza tuberculata). We propose reorganization to regain function without recovery of initial morphology as a potentially broad class of self-repair strategy beyond radially symmetrical animals, and discuss the implications of this finding on the evolution of self-repair strategies in animals.

  9. [Functional role of dragonfly legs before and after hatching: reorganization of coordinating interactions].

    Science.gov (United States)

    Sviderskiĭ, V L; Plotnikova, S I; Gorelkin, V S; Severina, I Iu; Isavnina, I L

    2012-11-01

    The characteristics of a structure-functional organization of leg apparatus were examined in the dragonfly Aeshna grandis: larvae of the final stadium, which legs perform a locomotion function and adults (imago) rising on a wing, which legs lose a locomotion function and are used mainly for catching a prey in the air. It has been demonstrated that legs of the imago practically do not differ from those of the larva either in shape or in proportion of segments of the leg and all changes in the functional role of legs of the imago are implemented due to modifications of mechanisms of limb muscle control and an appropriate reorganization or coordinating interactions. As it is proved by the obtained data, this reorganization concerns mechanisms of the generation of motor commands as well as close coordination of the activity of wing and leg apparatus and some others. The abovementioned mechanisms are discussed.

  10. Detection of Brain Reorganization in Pediatric Multiple Sclerosis Using Functional MRI

    Science.gov (United States)

    2015-10-01

    epilepsy patients as well as tumor and intravenous malformation patients who were placed under consideration to undergo pediatric brain surgery at...dissemination activities— journal articles, abstracts, and presentations—have friends or family who suffer from pediatric brain disorders; these...Page | 2 AWARD NUMBER: W81XWH-13-1-0464 TITLE: Detection of Brain Reorganization in Pediatric Multiple Sclerosis Using Functional MRI

  11. Adolescence and the reorganization of infant development: a neuro-psychoanalytic model.

    Science.gov (United States)

    Stortelder, Frans; Ploegmakers-Burg, Marian

    2010-01-01

    The psychoanalytic view of adolescence as a phase of turbulence and reorganization occupied a central position in child and adolescent psychiatry until about 1980. The view of adolescence as a silent-transition phase then prevailed and diverged from the psychoanalytic perspective. This article reviews infant and adolescent development using an interdisciplinary, neuro-psychoanalytic model in which psychoanalytic, neurobiological, and developmental perspectives converge and complement each other. Recent empirical research focuses attention on adolescence as a phase in which a far-reaching neurobiological and psychological reorganization takes place. According to the ontogenetic principle of psychoanalysis, the development and organization of the basic psychic functions occur in the first five years of life, while a reorganization takes place in adolescence. Neurobiological research confirms that the basic growth and maturation of the brain occurs in the first five years of life, and that a substantial reorganization in brain development transpires in adolescence. Research also verifies the clinical psychoanalytic concept that neurobiological and psychological maturation in adolescence remain unfinished till approximately age 23. The long-term and late biopsychosocial maturation in adolescence implies that adequate monitoring by parents and school remains necessary. The view that adolescents need to separate, and discover their individuality and independence alone, is unsupported by recent findings. The adolescent must acquire his independence, personal identity, and self-agency ("scaffolding") step by step. It is important that the adolescent knows that his parents are in the background monitoring and intervening as necessary; that he is not entirely alone, adrift and at risk for potential fragmentation. The long-term plasticity of the brain in adolescence implies greater vulnerability for the development of psychopathology, but offers opportunity for

  12. Rehabilitation of amelogenesis imperfecta using a reorganized approach: a case report.

    Science.gov (United States)

    Chan, Kingsley H C; Ho, Edward H T; Botelho, Michael G; Pow, Edmond H N

    2011-05-01

    Amelogenesis imperfecta is a genetic disorder that causes defective enamel development in both the primary and permanent dentitions. Significant tooth structure damage often results in various pulpal symptoms, occlusal disharmony, impaired function, and esthetic disfigurement. These problems pose great challenges to the clinician when rehabilitating patients with amelogenesis imperfecta. This case report describes an uncomplicated and logical way to reorganize, temporize, and completely restore an extensively damaged dentition caused by amelogenesis imperfecta.

  13. Opportunity Missed: Congressional Reorganization of the Army Air Service 1917-1920

    Science.gov (United States)

    1978-05-01

    consoli- dation on behalf of the Navy.71 Senator Gilbert M. Hitchcock (D) of Nebraska declared that nothing but confusion would re- sult from having...Aviation Mission is reprinted in full in the text of the hearings, beginning at page 20. Alfred F. Hurley, Billy Mitchell, 48-49. 16. House of...development of Mitchell’s crusade for airpower after 1920 is presented in Alfred F. Hurley, Billy Mitchell: Crusader for Airpower. 53. Senate, Reorganization

  14. Re-organization Impact on the Telekom Malaysias International Division Productivity

    OpenAIRE

    Ahasanul Haque; Ali Khatibi; Khaizura Karim

    2005-01-01

    International Divisions productivity was perceived to incline towards a downward trend which was contravened in 1996 re-organization objective of Telekom Malaysia. This study aims to analyze the root causes of this setback and recommend the solutions to improve the companys productivity. The method to diagnose the root cause was done through surveys and interviews. The data collection was carried out through questionnaire consisting of 85 questions. Total of 171 respondents from the internati...

  15. Jak3 enables chemokine-dependent actin cytoskeleton reorganization by regulating cofilin and Rac/Rhoa GTPases activation.

    Directory of Open Access Journals (Sweden)

    Xochitl Ambriz-Peña

    Full Text Available We have previously shown that Jak3 is involved in the signaling pathways of CCR7, CCR9 and CXCR4 in murine T lymphocytes and that Jak3⁻/⁻ lymphocytes display an intrinsic defect in homing to peripheral lymph nodes. However, the molecular mechanism underlying the defective migration observed in Jak3⁻/⁻ lymphocytes remains elusive. Here, it is demonstrated for the first time, that Jak3 is required for the actin cytoskeleton reorganization in T lymphocytes responding to chemokines. It was found that Jak3 regulates actin polymerization by controlling cofilin inactivation in response to CCL21 and CXCL12. Interestingly, cofilin inactivation was not precluded in PTX- treated cells despite their impaired actin polymerization. Additionally, Jak3 was required for small GTPases Rac1 and RhoA activation, which are indispensable for acquisition of the migratory cell phenotype and the generation of a functional leading edge and uropod, respectively. This defect correlates with data obtained by time-lapse video-microscopy showing an incompetent uropod formation and impaired motility in Jak3-pharmacologically inhibited T lymphocytes. Our data support a new model in which Jak3 and heterotrimeric G proteins can use independent, but complementary, signaling pathways to regulate actin cytoskeleton dynamics during cell migration in response to chemokines.

  16. Platelet derived growth factor (PDGF) contained in Platelet Rich Plasma (PRP) stimulates migration of osteoblasts by reorganizing actin cytoskeleton.

    Science.gov (United States)

    Casati, Lavinia; Celotti, Fabio; Negri-Cesi, Paola; Sacchi, Maria Cristina; Castano, Paolo; Colciago, Alessandra

    2014-01-01

    Platelet-rich plasma (PRP) is a platelet concentrate in a small volume of plasma. It is highly enriched in growth factors able to stimulate the migration and growth of bone-forming cells. PRP is often used in clinical applications, as dental surgery and fracture healing. Platelet derived growth factor (PDGF), is highly concentrated in PRP and it was shown in our previous studies to provide the chemotactic stimulus to SaOS-2 osteoblasts to move in a microchemotaxis assay. Aim of the present studies is to analyze the effects of a PRP pretreatment (short time course: 30-150 min) of SaOS-2 cells with PRP on the organization of actin cytoskeleton, the main effector of cell mobility. The results indicate that a pretreatment with PRP increases chemokinesis and chemotaxis and concomitantly induces the organization of actin microfilaments, visualized by immunocytochemistry, in a directionally elongated phenotype, which is characteristic of the cells able to move. PRP also produces a transient increase in the expression of PGDF α receptor. This reorganization is blocked by the immunoneutralization of PDGF demonstrating the responsibility of this growth factor in triggering the mechanisms responsible for cellular movements.

  17. Stability-dependent behavioural and electro-cortical reorganizations during intentional switching between bimanual tapping modes.

    Science.gov (United States)

    Tallet, Jessica; Barral, Jérôme; James, Clara; Hauert, Claude-Alain

    2010-10-11

    This study investigated behavioural and electro-cortical reorganizations accompanying intentional switching between two distinct bimanual coordination tapping modes (In-phase and Anti-phase) that differ in stability when produced at the same movement rate. We expected that switching to a less stable tapping mode (In-to-Anti switching) would lead to larger behavioural perturbations and require supplementary neural resources than switching to a more stable tapping mode (Anti-to-In switching). Behavioural results confirmed that the In-to-Anti switching lasted longer than the Anti-to-In switching. A general increase in attention-related neural activity was found at the moment of switching for both conditions. Additionally, two condition-dependent EEG reorganizations were observed. First, a specific increase in cortico-cortical coherence appeared exclusively during the In-to-Anti switching. This result may reflect a strengthening in inter-regional communication in order to engage in the subsequent, less stable, tapping mode. Second, a decrease in motor-related neural activity (increased beta spectral power) was found for the Anti-to-In switching only. The latter effect may reflect the interruption of the previous, less stable, tapping mode. Given that previous results on spontaneous Anti-to-In switching revealing an inverse pattern of EEG reorganization (decreased beta spectral power), present findings give new insight on the stability-dependent neural correlates of intentional motor switching.

  18. Reorganization of the Connectivity between Elementary Functions – A Model Relating Conscious States to Neural Connections

    Directory of Open Access Journals (Sweden)

    Jesper Mogensen

    2017-04-01

    Full Text Available In the present paper it is argued that the “neural correlate of consciousness” (NCC does not appear to be a separate “module” – but an aspect of information processing within the neural substrate of various cognitive processes. Consequently, NCC can only be addressed adequately within frameworks that model the general relationship between neural processes and mental states – and take into account the dynamic connectivity of the brain. We presently offer the REFGEN (general reorganization of elementary functions model as such a framework. This model builds upon and expands the REF (reorganization of elementary functions and REFCON (of elementary functions and consciousness models. All three models integrate the relationship between the neural and mental layers of description via the construction of an intermediate level dealing with computational states. The importance of experience based organization of neural and cognitive processes is stressed. The models assume that the mechanisms of consciousness are in principle the same as the basic mechanisms of all aspects of cognition – when information is processed to a sufficiently “high level” it becomes available to conscious experience. The NCC is within the REFGEN model seen as aspects of the dynamic and experience driven reorganizations of the synaptic connectivity between the neurocognitive “building blocks” of the model – the elementary functions.

  19. Reorganization of microtubular cytoskeleton and formation of cellular processes during post-telophase in haemanthus endosperm.

    Science.gov (United States)

    Bajer, A S; Smirnova, E A

    1999-10-01

    We followed time-dependent post-telophase reorganization of the microtubule cytoskeleton on immunostained preparations of endosperm of the higher plant Haemanthus. After completion of mitosis, the phragmoplast continued to reorganize for several hours. This prompted the formation of phragmoplast-like derivatives (secondary and accessory phragmoplasts and peripheral microtubular ring). Next, elongated cellular protrusions (processes) appeared at the cell periphery. These processes contained long microtubule bundles and disorderly arranged actin filaments. Microtubule converging centers or accessory phragmoplasts were often present at the tips of the processes. Observation in vivo demonstrated that processes were formed at the cell periphery as extensions of lammelipodia or filopodia-type protrusions that commonly terminated with cytoplasmic blobs. We suggest that processes are derivatives of a peripheral microtubular ring that reorganizes gradually into cellular protrusions. Endosperm processes have several features of neuronal cells, or animal somatic cells with overexpressed MAPs. Since microtubule-containing processes were never detected shortly after extrusion of the cells from the embryo sac, this course of events might be restricted specifically to extruded endosperm and triggered either by removal of cells, their placement in monolayer on agar substrate, or both. Thus, post telophase behavior of endosperm cells offers a novel experimental system for studies of cytoskeleton in higher plants.

  20. Experimental evidence of dynamic re-organization of evolving landscapes under changing climatic forcing

    Science.gov (United States)

    Singh, Arvind; Tejedor, Alejandro; Zaliapin, Ilya; Reinhardt, Liam; Foufoula-Georgiou, Efi

    2015-04-01

    The aim of this study is to better understand the dynamic re-organization of an evolving landscape under a scenario of changing climatic forcing for improving our knowledge of geomorphic transport laws under transient conditions and developing predictive models of landscape response to external perturbations. Real landscape observations for long-term analysis are limited and to this end a high resolution controlled laboratory experiment was conducted at the St. Anthony Falls laboratory at the University of Minnesota. Elevation data were collected at temporal resolution of 5 mins and spatial resolution of 0.5 mm as the landscape approached steady state (constant uplift and precipitation rate) and in the transient state (under the same uplift and 5x precipitation). The results reveal rapid topographic re-organization under a five-fold precipitation increase with the fluvial regime expanding into the previously debris dominated regime, accelerated erosion happening at hillslope scales, and rivers shifting from an erosion-limited to a transport-limited regime. From a connectivity and clustering analysis of the erosional and depositional events, we demonstrate the strikingly different spatial patterns of landscape evolution under steady-state (SS) and transient-state (TS), even when the time under SS is "stretched" compared to that under TS such as to match the total volume and PDF of erosional and depositional amounts. We quantify the spatial coupling of hillslopes and channels and demonstrate that hillslopes lead and channels follow in re-organizing the whole landscape under such an amplified precipitation regime.

  1. Dynamic neural network reorganization associated with second language vocabulary acquisition: a multimodal imaging study.

    Science.gov (United States)

    Hosoda, Chihiro; Tanaka, Kanji; Nariai, Tadashi; Honda, Manabu; Hanakawa, Takashi

    2013-08-21

    It remains unsettled whether human language relies exclusively on innately privileged brain structure in the left hemisphere or is more flexibly shaped through experiences, which induce neuroplastic changes in potentially relevant neural circuits. Here we show that learning of second language (L2) vocabulary and its cessation can induce bidirectional changes in the mirror-reverse of the traditional language areas. A cross-sectional study identified that gray matter volume in the inferior frontal gyrus pars opercularis (IFGop) and connectivity of the IFGop with the caudate nucleus and the superior temporal gyrus/supramarginal (STG/SMG), predominantly in the right hemisphere, were positively correlated with L2 vocabulary competence. We then implemented a cohort study involving 16 weeks of L2 training in university students. Brain structure before training did not predict the later gain in L2 ability. However, training intervention did increase IFGop volume and reorganization of white matter including the IFGop-caudate and IFGop-STG/SMG pathways in the right hemisphere. These "positive" plastic changes were correlated with the gain in L2 ability in the trained group but were not observed in the control group. We propose that the right hemispheric network can be reorganized into language-related areas through use-dependent plasticity in young adults, reflecting a repertoire of flexible reorganization of the neural substrates responding to linguistic experiences.

  2. Factors Influencing Adaptive Capacity in the Reorganization of Forest Management in Alaska

    Directory of Open Access Journals (Sweden)

    Colin Beier

    2011-03-01

    Full Text Available Several studies of U.S. National Forests suggest that declines of their associated forest products industries were driven by synergistic changes in federal governance and market conditions during the late 20th century. In Alaska, dramatic shifts in the economic and political settings of the Tongass National Forest (Tongass drove changes in governance leading to collapse of an industrial forest management system in the early 1990s. However, 15 years since collapse, the reorganization of Tongass governance to reflect 'new' economic and political realities has not progressed. To understand both the factors that hinder institutional change (inertia and the factors that enable progress toward reorganization (adaptation, I analyzed how Tongass forest management, specifically timber sale planning, has responded to changes in market conditions, local industry structure, and larger-scale political governance. Inertia was evidenced by continued emphasis on even-aged management and large-scale harvesting, i.e., the retention of an industrial forestry philosophy that, in the current political situation, yields mostly litigation and appeals, and relatively few forest products. Adaptation was evidenced by flexibility in harvest methods, a willingness to meet local demand instead of political targets, and a growing degree of cooperation with environmental advocacy groups. New partnerships, markets, and political leaders at state and national levels can frame a new blueprint for reorganization of Tongass management toward a more sustainable future.

  3. Functional connectivity of visual cortex in the blind follows retinotopic organization principles.

    Science.gov (United States)

    Striem-Amit, Ella; Ovadia-Caro, Smadar; Caramazza, Alfonso; Margulies, Daniel S; Villringer, Arno; Amedi, Amir

    2015-06-01

    Is visual input during critical periods of development crucial for the emergence of the fundamental topographical mapping of the visual cortex? And would this structure be retained throughout life-long blindness or would it fade as a result of plastic, use-based reorganization? We used functional connectivity magnetic resonance imaging based on intrinsic blood oxygen level-dependent fluctuations to investigate whether significant traces of topographical mapping of the visual scene in the form of retinotopic organization, could be found in congenitally blind adults. A group of 11 fully and congenitally blind subjects and 18 sighted controls were studied. The blind demonstrated an intact functional connectivity network structural organization of the three main retinotopic mapping axes: eccentricity (centre-periphery), laterality (left-right), and elevation (upper-lower) throughout the retinotopic cortex extending to high-level ventral and dorsal streams, including characteristic eccentricity biases in face- and house-selective areas. Functional connectivity-based topographic organization in the visual cortex was indistinguishable from the normally sighted retinotopic functional connectivity structure as indicated by clustering analysis, and was found even in participants who did not have a typical retinal development in utero (microphthalmics). While the internal structural organization of the visual cortex was strikingly similar, the blind exhibited profound differences in functional connectivity to other (non-visual) brain regions as compared to the sighted, which were specific to portions of V1. Central V1 was more connected to language areas but peripheral V1 to spatial attention and control networks. These findings suggest that current accounts of critical periods and experience-dependent development should be revisited even for primary sensory areas, in that the connectivity basis for visual cortex large-scale topographical organization can develop without any

  4. Proton magnetic resonance spectroscopy of the motor cortex in cervical myelopathy.

    Science.gov (United States)

    Kowalczyk, Izabela; Duggal, Neil; Bartha, Robert

    2012-02-01

    Alterations in motor function in cervical myelopathy secondary to degenerative disease may be due to local effects of spinal compression or distal effects related to cortical reorganization. This prospective study characterizes differences in metabolite levels in the motor cortex, specifically N-acetylaspartate, creatine, choline, myo-inositol and glutamate plus glutamine, due to alterations in cortical function in patients with reversible spinal cord compression compared with healthy controls. We hypothesized that N-acetylaspartate/creatine levels would be decreased in the motor cortex of patients with cervical myelopathy due to reduced neuronal integrity/function and myo-inositol/creatine levels would be increased due to reactive gliosis. Twenty-four patients with cervical myelopathy and 11 healthy controls underwent proton-magnetic resonance spectroscopy on a 3.0 Tesla Siemens Magnetom Tim Trio MRI. Areas of activation from functional magnetic resonance imaging scans of a finger-tapping paradigm were used to localize a voxel on the side of greater motor deficit in the myelopathy group (n = 10 on right side and n = 14 on left side of the brain) and on each side of the motor cortex in controls. Neurological function was measured with the Neck Disability Index, modified Japanese Orthopaedic Association and American Spinal Injury Association questionnaires. Metabolite levels were measured relative to total creatine within the voxel of interest. No metabolite differences were detected between the right side and left side of the motor cortex in controls. The myelopathy group had significantly decreased neurological function compared with the control group (Neck Disability Index: P motor cortex of the myelopathy group (1.21 ± 0.07) compared with the right (1.37 ± 0.03; P = 0.01) and left (1.38 ± 0.03; P = 0.007) motor cortex in controls suggesting neuronal damage or dysfunction distal to the lesion in the spine. No difference was

  5. Mapping Prefrontal Cortex Functions in Human Infancy

    Science.gov (United States)

    Grossmann, Tobias

    2013-01-01

    It has long been thought that the prefrontal cortex, as the seat of most higher brain functions, is functionally silent during most of infancy. This review highlights recent work concerned with the precise mapping (localization) of brain activation in human infants, providing evidence that prefrontal cortex exhibits functional activation much…

  6. 75 FR 69621 - Foreign-Trade Zone 50-Long Beach, CA; Application for Reorganization/Expansion Under Alternative...

    Science.gov (United States)

    2010-11-15

    ...-Trade Zone 50--Long Beach, CA; Application for Reorganization/Expansion Under Alternative Site Framework...)--909 East Colon Street, Wilmington; Site 2 (1,844 acres)-- California Commerce Center, Ontario; Site...

  7. The Association Between Workers' Employability and Burnout in a Reorganization Context: Longitudinal Evidence Building Upon the Conservation of Resources Theory

    NARCIS (Netherlands)

    Cuyper, de Nele; Raeder, Sabine; Heijden, van der Beatrice I.J.M.; Wittekind, Anette

    2012-01-01

    This longitudinal study probes the relationship between employability and burnout among employees from a company undergoing reorganization. We advanced employability as a personal resource that relates negatively to burnout. We expected that this hypothesis would hold for different operationalizatio

  8. Addiction and the adrenal cortex

    Science.gov (United States)

    Vinson, Gavin P; Brennan, Caroline H

    2013-01-01

    Substantial evidence shows that the hypophyseal–pituitary–adrenal (HPA) axis and corticosteroids are involved in the process of addiction to a variety of agents, and the adrenal cortex has a key role. In general, plasma concentrations of cortisol (or corticosterone in rats or mice) increase on drug withdrawal in a manner that suggests correlation with the behavioural and symptomatic sequelae both in man and in experimental animals. Corticosteroid levels fall back to normal values in resumption of drug intake. The possible interactions between brain corticotrophin releasing hormone (CRH) and proopiomelanocortin (POMC) products and the systemic HPA, and additionally with the local CRH–POMC system in the adrenal gland itself, are complex. Nevertheless, the evidence increasingly suggests that all may be interlinked and that CRH in the brain and brain POMC products interact with the blood-borne HPA directly or indirectly. Corticosteroids themselves are known to affect mood profoundly and may themselves be addictive. Additionally, there is a heightened susceptibility for addicted subjects to relapse in conditions that are associated with change in HPA activity, such as in stress, or at different times of the day. Recent studies give compelling evidence that a significant part of the array of addictive symptoms is directly attributable to the secretory activity of the adrenal cortex and the actions of corticosteroids. Additionally, sex differences in addiction may also be attributable to adrenocortical function: in humans, males may be protected through higher secretion of DHEA (and DHEAS), and in rats, females may be more susceptible because of higher corticosterone secretion. PMID:23825159

  9. Cenozoic tectonic reorganizations of the Death Valley region, southeast California and southwest Nevada

    Science.gov (United States)

    Fridrich, Christopher J.; Thompson, Ren A.

    2011-01-01

    The Death Valley region, of southeast California and southwest Nevada, is distinct relative to adjacent regions in its structural style and resulting topography, as well as in the timing of basin-range extension. Cenozoic basin-fill strata, ranging in age from greater than or equal to 40 to approximately 2 million years are common within mountain-range uplifts in this region. The tectonic fragmentation and local uplift of these abandoned basin-fills indicate a multistage history of basin-range tectonism. Additionally, the oldest of these strata record an earlier, pre-basin-range interval of weak extension that formed broad shallow basins that trapped sediments, without forming basin-range topography. The Cenozoic basin-fill strata record distinct stratigraphic breaks that regionally cluster into tight age ranges, constrained by well-dated interbedded volcanic units. Many of these stratigraphic breaks are long recognized formation boundaries. Most are angular unconformities that coincide with abrupt changes in depositional environment. Deposits that bound these unconformities indicate they are weakly diachronous; they span about 1 to 2 million years and generally decrease in age to the west within individual basins and regionally, across basin boundaries. Across these unconformities, major changes are found in the distribution and provenance of basin-fill strata, and in patterns of internal facies. These features indicate rapid, regionally coordinated changes in strain patterns defined by major active basin-bounding faults, coincident with step-wise migrations of the belt of active basin-range tectonism. The regionally correlative unconformities thus record short intervals of radical tectonic change, here termed "tectonic reorganizations." The intervening, longer (about 3- to 5-million-year) interval of gradual, monotonic evolution in the locus and style of tectonism are called "tectonic stages." The belt of active tectonism in the Death Valley region has abruptly

  10. Npas4 Expression in Two Experimental Models of the Barrel Cortex Plasticity

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    Aleksandra Kaliszewska

    2015-01-01

    Full Text Available Npas4 has recently been identified as an important factor in brain plasticity, particularly in mechanisms of inhibitory control. Little is known about Npas4 expression in terms of cortical plasticity. In the present study expressions of Npas4 and the archetypal immediate early gene (IEG c-Fos were investigated in the barrel cortex of mice after sensory deprivation (sparing one row of whiskers for 7 days or sensory conditioning (pairing stimulation of one row of whiskers with aversive stimulus. Laser microdissection of individual barrel rows allowed for analysis of IEGs expression precisely in deprived and nondeprived barrels (in deprivation study or stimulated and nonstimulated barrels (in conditioning study. Cortex activation by sensory conditioning was found to upregulate the expression of both Npas4 and c-Fos. Reorganization of cortical circuits triggered by removal of selected rows of whiskers strongly affected c-Fos but not Npas4 expression. We hypothesize that increased inhibitory synaptogenesis observed previously after conditioning may be mediated by Npas4 expression.

  11. Functional reorganization of the auditory pathways (or lack thereof) in callosal agenesis is predicted by monaural sound localization performance.

    Science.gov (United States)

    Paiement, Philippe; Champoux, François; Bacon, Benoit A; Lassonde, Maryse; Mensour, Boualem; Leroux, Jean-Maxime; Lepore, Franco

    2010-01-01

    Neuroimaging studies show that permanent peripheral lesions such as unilateral deafness cause functional reorganization in the auditory pathways. However, functional reorganization of the auditory pathways as a result of higher-level damage or abnormalities remains poorly investigated. A relatively recent behavioural study points to functional changes in the auditory pathways in some, but interestingly not in all, of the acallosal individuals that were tested. The present study uses fMRI to investigate auditory activities in both cerebral hemispheres in those same acallosal subjects in order to directly investigate the contributions of ipsilateral and contralateral functional pathways reorganization. Predictions were made that functional reorganization could be predicted from behavioural performance. As reported previously in a number of neuroimaging studies, results showed that in neurologically intact subjects, binaural stimulation induced balanced activities between both hemispheres, while monaural stimulation induced strong contralateral activities and weak ipsilateral activities. In accordance with behavioural predictions, some acallosal subjects showed patterns of auditory cortical activities that were similar to those observed in neurologically intact subjects while others showed functional reorganization of the auditory pathways. Essentially they showed a significant increase and a significant decrease of neural activities in the contralateral and/or ipsilateral pathways, respectively. These findings indicate that at least in some acallosal subjects, functional reorganization inside the auditory pathways does contribute to compensate for the absence of the corpus callosum.

  12. Visual attentional load influences plasticity in the human motor cortex.

    Science.gov (United States)

    Kamke, Marc R; Hall, Michelle G; Lye, Hayley F; Sale, Martin V; Fenlon, Laura R; Carroll, Timothy J; Riek, Stephan; Mattingley, Jason B

    2012-05-16

    Neural plasticity plays a critical role in learning, memory, and recovery from injury to the nervous system. Although much is known about the physical and physiological determinants of plasticity, little is known about the influence of cognitive factors. In this study, we investigated whether selective attention plays a role in modifying changes in neural excitability reflecting long-term potentiation (LTP)-like plasticity. We induced LTP-like effects in the hand area of the human motor cortex using transcranial magnetic stimulation (TMS). During the induction of plasticity, participants engaged in a visual detection task with either low or high attentional demands. Changes in neural excitability were assessed by measuring motor-evoked potentials in a small hand muscle before and after the TMS procedures. In separate experiments plasticity was induced either by paired associative stimulation (PAS) or intermittent theta-burst stimulation (iTBS). Because these procedures induce different forms of LTP-like effects, they allowed us to investigate the generality of any attentional influence on plasticity. In both experiments reliable changes in motor cortex excitability were evident under low-load conditions, but this effect was eliminated under high-attentional load. In a third experiment we investigated whether the attentional task was associated with ongoing changes in the excitability of motor cortex, but found no difference in evoked potentials across the levels of attentional load. Our findings indicate that in addition to their role in modifying sensory processing, mechanisms of attention can also be a potent modulator of cortical plasticity.

  13. Correspondence between altered functional and structural connectivity in the contralesional sensorimotor cortex after unilateral stroke in rats: a combined resting-state functional MRI and manganese-enhanced MRI study

    Science.gov (United States)

    van Meer, Maurits PA; van der Marel, Kajo; Otte, Willem M; Berkelbach van der Sprenkel, Jan Willem; Dijkhuizen, Rick M

    2010-01-01

    This study shows a significant correlation between functional connectivity, as measured with resting-state functional magnetic resonance imaging (MRI), and neuroanatomical connectivity, as measured with manganese-enhanced MRI, in rats at 10 weeks after unilateral stroke and in age-matched controls. Reduced interhemispheric functional connectivity between the contralesional primary motor cortex (M1) and ipsilesional sensorimotor cortical regions was accompanied by a decrease in transcallosal manganese transfer from contralesional M1 to the ipsilesional sensorimotor cortex after a large unilateral stroke. Increased intrahemispheric functional connectivity in the contralesional sensorimotor cortex was associated with locally enhanced neuroanatomical tracer uptake, which underlines the strong link between functional and structural reorganization of neuronal networks after stroke. PMID:20664609

  14. Sparse representation of sounds in the unanesthetized auditory cortex.

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    Tomás Hromádka

    2008-01-01

    Full Text Available How do neuronal populations in the auditory cortex represent acoustic stimuli? Although sound-evoked neural responses in the anesthetized auditory cortex are mainly transient, recent experiments in the unanesthetized preparation have emphasized subpopulations with other response properties. To quantify the relative contributions of these different subpopulations in the awake preparation, we have estimated the representation of sounds across the neuronal population using a representative ensemble of stimuli. We used cell-attached recording with a glass electrode, a method for which single-unit isolation does not depend on neuronal activity, to quantify the fraction of neurons engaged by acoustic stimuli (tones, frequency modulated sweeps, white-noise bursts, and natural stimuli in the primary auditory cortex of awake head-fixed rats. We find that the population response is sparse, with stimuli typically eliciting high firing rates (>20 spikes/second in less than 5% of neurons at any instant. Some neurons had very low spontaneous firing rates (<0.01 spikes/second. At the other extreme, some neurons had driven rates in excess of 50 spikes/second. Interestingly, the overall population response was well described by a lognormal distribution, rather than the exponential distribution that is often reported. Our results represent, to our knowledge, the first quantitative evidence for sparse representations of sounds in the unanesthetized auditory cortex. Our results are compatible with a model in which most neurons are silent much of the time, and in which representations are composed of small dynamic subsets of highly active neurons.

  15. Investigation of Fragments Reorganization in Old Town Public Spaces%旧城公共空间的碎片重组初探

    Institute of Scientific and Technical Information of China (English)

    何小欣

    2011-01-01

    该文从居民的日常生活和交往行为出发,引入环境心理学、行为学的相关理论,分析了城市公共空间大型化的消极影响,以及小尺度公共空间在旧城中的存在价值,最后提出“旧城公共空间碎片重组”的概念和初步方案.%According to the daily life and the communicative action of residents; by introducing the environmental psychology and the behavior philosophy; the article analyzes the negative impact of large-scale urban public spaces; and the advantages of small-scale urban public spaces in the old town; and finally proposes the concept and the preliminary programs of" Reorganization of Old Urban Public Fragment Spaces".

  16. Increases in the numerical density of GAT-1 positive puncta in the barrel cortex of adult mice after fear conditioning.

    Directory of Open Access Journals (Sweden)

    Ewa Siucinska

    Full Text Available Three days of fear conditioning that combines tactile stimulation of a row of facial vibrissae (conditioned stimulus, CS with a tail shock (unconditioned stimulus, UCS expands the representation of "trained" vibrissae, which can be demonstrated by labeling with 2-deoxyglucose in layer IV of the barrel cortex. We have also shown that functional reorganization of the primary somatosensory cortex (S1 increases GABAergic markers in the hollows of "trained" barrels of the adult mouse. This study investigated how whisker-shock conditioning (CS+UCS affected the expression of puncta of a high-affinity GABA plasma membrane transporter GAT-1 in the barrel cortex of mice 24 h after associative learning paradigm. We found that whisker-shock conditioning (CS+UCS led to increase expression of neuronal and astroglial GAT-1 puncta in the "trained" row compared to controls: Pseudoconditioned, CS-only, UCS-only and Naïve animals. These findings suggest that fear conditioning specifically induces activation of systems regulating cellular levels of the inhibitory neurotransmitter GABA.

  17. Long lasting structural changes in primary motor cortex after motor skill learning: a behavioural and stereological study.

    Science.gov (United States)

    Morales, Paola

    2008-01-01

    Many motor skills, once acquired, are stored over a long time period, probably sustained by permanent neuronal changes. Thus, in this paper we have investigated with quantitative stereology the generation and persistence of neuronal density changes in primary motor cortex (MI) following motor skill learning (skilled reaching task). Rats were trained a lateralised reaching task during an "early" (22-31 days old) or "late" (362-371 days old) postnatal period. The trained and corresponding control rats were sacrificed at day 372, immediately after the behavioural testing. The "early" trained group preserved the learned skilled reaching task when tested at day 372, without requiring any additional training. The "late" trained group showed a similar capacity to that of the "early" trained group for learning the skilled reaching task. All trained animals ("early" and "late" trained groups) showed a significant Inter hemispheric decrease of neuronal density in the corresponding motor forelimb representation area of MI (cortical layers II-III). It is concluded that learning a skilled reaching task implies long lasting structural changes in restricted cortical regions of the motor cortex. The generation and persistence of these changes probably reflect a plastic reorganization for storing and retrieving motor skills. The plastic changes were also observed in the older rats, suggesting that motor cortex maintains its plastic capacity throughout the lifespan.

  18. Preparatory attention in visual cortex.

    Science.gov (United States)

    Battistoni, Elisa; Stein, Timo; Peelen, Marius V

    2017-05-01

    Top-down attention is the mechanism that allows us to selectively process goal-relevant aspects of a scene while ignoring irrelevant aspects. A large body of research has characterized the effects of attention on neural activity evoked by a visual stimulus. However, attention also includes a preparatory phase before stimulus onset in which the attended dimension is internally represented. Here, we review neurophysiological, functional magnetic resonance imaging, magnetoencephalography, electroencephalography, and transcranial magnetic stimulation (TMS) studies investigating the neural basis of preparatory attention, both when attention is directed to a location in space and when it is directed to nonspatial stimulus attributes (content-based attention) ranging from low-level features to object categories. Results show that both spatial and content-based attention lead to increased baseline activity in neural populations that selectively code for the attended attribute. TMS studies provide evidence that this preparatory activity is causally related to subsequent attentional selection and behavioral performance. Attention thus acts by preactivating selective neurons in the visual cortex before stimulus onset. This appears to be a general mechanism that can operate on multiple levels of representation. We discuss the functional relevance of this mechanism, its limitations, and its relation to working memory, imagery, and expectation. We conclude by outlining open questions and future directions. © 2017 New York Academy of Sciences.

  19. Entorhinal cortex stimulation modulates amygdala and piriform cortex responses to olfactory bulb inputs in the rat.

    Science.gov (United States)

    Mouly, A-M; Di Scala, G

    2006-01-01

    The rodent olfactory bulb sends direct projections to the piriform cortex and to two structures intimately implicated in memory processes, the entorhinal cortex and the amygdala. The piriform cortex has monosynaptic projections with the amygdala and the piriform cortex and is therefore in a position to modulate olfactory input either directly in the piriform cortex, or via the amygdala. In order to investigate this hypothesis, field potential signals induced in anesthetized rats by electrical stimulation of the olfactory bulb or the entorhinal cortex were recorded simultaneously in the piriform cortex (anterior part and posterior part) and the amygdala (basolateral nucleus and cortical nucleus). Single-site paired-pulse stimulation was used to assess the time courses of short-term inhibition and facilitation in each recording site in response to electrical stimulation of the olfactory bulb and entorhinal cortex. Paired-pulse stimulation of the olfactory bulb induced homosynaptic inhibition for short interpulse interpulse intervals (20-30 ms) in all the recording sites, with a significantly lower degree of inhibition in the anterior piriform cortex than in the other structures. At longer intervals (40-80 ms), paired-pulse facilitation was observed in all the structures. Paired-pulse stimulation of the entorhinal cortex mainly resulted in inhibition for the shortest interval duration (20 ms) in anterior piriform cortex, posterior piriform cortex and amygdala basolateral but not cortical nucleus. Double-site paired-pulse stimulation was then applied to determine if stimulation of the entorhinal cortex can modulate responses to olfactory bulb stimulation. For short interpulse intervals (20 ms) heterosynaptic inhibition was observed in anterior piriform cortex, posterior piriform cortex and amygdala basolateral but not cortical nucleus. The level of inhibition was greater in the basolateral nucleus than in the other structures. Taken together these data suggest that the

  20. Single-cortex is better than double-cortex in fibula grafts for large tibia bone defect in a 2-year-old child

    Science.gov (United States)

    Li, Jianbin; Pan, Zhijun; Yan, Shigui; Zhao, Xiang

    2017-01-01

    Abstract Background: Large bone defect in infant or small patients has been little reported and the management of such a patient is difficult. Considering the little knowledge of this area, we present this special case of a successful single-cortex fibula graft for the treatment of a large tibia bone defect in a 2-year-old patient to share our experience. Case summary: A 2-year-old male patient presented to our hospital with history of leg pain for 4 months. According to his medical records, he was involved in a traffic accident and diagnosed with open tibia fracture. A previous surgery of emergent debridement and external fixation was performed in our institution, leaving a 6-cm tibia bone defect. After that this patient received several times of vacuum sealing drainage (VSD), skin grafting, and changed external fixation to cast because of pin tract infection. The physical examination of the patient showed a healed skin wound and a good dorsal arterial pulse. X-ray indicated a large bone defect at the tibia fracture site with osteosclerosis at the fracture sections. This patient received ipsilateral single-cortex vascularized single-cortex fibula graft, other than double-cortex fibula graft. X-ray and CT scan 4 months after the operation confined bone healing. The patient returned to normal activities with an inconspicuous limb. Conclusion: Ipsilateral single-cortex fibula graft is effective for the treatment of large tibia bone defect in infant or small aged patients. It exhibited better potential benefits than double-cortex graft in such cases. PMID:28151885

  1. Reorganization of visual fields after periventricular haemorrhagic infarction: potentials and limitations.

    Science.gov (United States)

    Guzzetta, Andrea; Fiori, Simona; Scelfo, Danilo; Conti, Eugenia; Bancale, Ada

    2013-11-01

    Visual functions are often impaired in preterm infants with periventricular haemorrhagic infarction, because of the involvement of the region where the optic radiations are located. In some cases an unexpected sparing of the visual fields has been described, and related to the plasticity of thalamo-cortical afferents that are supposedly able to bypass the lesion when it occurs in the early third trimester of gestation. We systematically reviewed the literature in the field to determine the limits and potentials of this type of reorganization. We found four studies meeting our criteria, from which we extracted case reports on 19 individuals with intraventricular haemorrhagic infarction. Eleven of the 19 did not have visual field defects, five had a bilateral visual field defect, and the remaining three had a unilateral visual field defect. The involvement of the optic radiations was often associated with normal visual fields as only one of the four individuals with damaged optic radiations showed visual field defects. Conversely, the presence of basal ganglia/thalamus involvement apparently prevented such reorganization, as the only two individuals with unilateral field restriction and available magnetic resonance imaging data both showed abnormalities in those structures. Consistent with this, we report on a further individual in which visual field restriction was associated with abnormal tractography on brain magnetic resonance imaging. Overall, this review supports the existence of effective mechanisms of plastic reorganization that allow a rewiring of geniculo-calcarine connections with restoration of full field vision but which are hindered by the involvement of the basal ganglia and thalamus.

  2. Identifying functional reorganization of spelling networks: An Individual Peak Probability Comparison Approach.

    Directory of Open Access Journals (Sweden)

    Jeremy Joseph Purcell

    2013-12-01

    Full Text Available Previous research has shown that damage to the neural substrates of orthographic processing can lead to functional reorganization during reading (Tsapkini et al., 2011; in this research we ask if the same is true for spelling. To examine the functional reorganization of spelling networks we present a novel three-stage Individual Peak Probability Comparison (IPPC analysis approach for comparing the activation patterns obtained during fMRI of spelling in a single brain-damaged individual with dysgraphia to those obtained in a set of non-impaired control participants. The first analysis stage characterizes the convergence in activations across non-impaired control participants by applying a technique typically used for characterizing activations across studies: Activation Likelihood Estimate (ALE (Turkeltaub et al., 2002. This method was used to identify locations that have a high likelihood of yielding activation peaks in the non-impaired participants. The second stage provides a characterization of the degree to which the brain-damaged individual’s activations correspond to the group pattern identified in Stage 1. This involves performing a Mahalanobis distance statistics analysis (Tsapkini et al., 2011 that compares each of a control group’s peak activation locations to the nearest peak generated by the brain-damaged individual. The third stage evaluates the extent to which the brain-damaged individual’s peaks are atypical relative to the range of individual variation among the control participants. This IPPC analysis allows for a quantifiable, statistically sound method for comparing an individual’s activation pattern to the patterns observed in a control group and, thus, provides a valuable tool for identifying functional reorganization in a brain-damaged individual with impaired spelling. Furthermore, this approach can be applied more generally to compare any individual’s activation pattern with that of a set of other individuals.

  3. Reorganization of finger coordination patterns through motor exploration in individuals after stroke.

    Science.gov (United States)

    Ranganathan, Rajiv

    2017-09-11

    Impairment of hand and finger function after stroke is common and affects the ability to perform activities of daily living. Even though many of these coordination deficits such as finger individuation have been well characterized, it is critical to understand how stroke survivors learn to explore and reorganize their finger coordination patterns for optimizing rehabilitation. In this study, I examine the use of a body-machine interface to assess how participants explore their movement repertoire, and how this changes with continued practice. Ten participants with chronic stroke wore a data glove and the finger joint angles were mapped on to the position of a cursor on a screen. The task of the participants was to move the cursor back and forth between two specified targets on a screen. Critically, the map between the finger movements and cursor motion was altered so that participants sometimes had to generate coordination patterns that required finger individuation. There were two phases to the experiment - an initial assessment phase on day 1, followed by a learning phase (days 2-5) where participants trained to reorganize their coordination patterns. Participants showed difficulty in performing tasks which had maps that required finger individuation, and the degree to which they explored their movement repertoire was directly related to clinical tests of hand function. However, over four sessions of practice, participants were able to learn to reorganize their finger movement coordination pattern and improve their performance. Moreover, training also resulted in improvements in movement repertoire outside of the context of the specific task during free exploration. Stroke survivors show deficits in movement repertoire in their paretic hand, but facilitating movement exploration during training can increase the movement repertoire. This suggests that exploration may be an important element of rehabilitation to regain optimal function.

  4. Phospholipase d activation correlates with microtubule reorganization in living plant cells.

    Science.gov (United States)

    Dhonukshe, Pankaj; Laxalt, Ana M; Goedhart, Joachim; Gadella, Theodorus W J; Munnik, Teun

    2003-11-01

    A phospholipase D (PLD) was shown recently to decorate microtubules in plant cells. Therefore, we used tobacco BY-2 cells expressing the microtubule reporter GFP-MAP4 to test whether PLD activation affects the organization of plant microtubules. Within 30 min of adding n-butanol, a potent activator of PLD, cortical microtubules were released from the plasma membrane and partially depolymerized, as visualized with four-dimensional confocal imaging. The isomers sec- and tert-butanol, which did not activate PLD, did not affect microtubule organization. The effect of treatment on PLD activation was monitored by the in vivo formation of phosphatidylbutanol, a specific reporter of PLD activity. Tobacco cells also were treated with mastoparan, xylanase, NaCl, and hypoosmotic stress as reported activators of PLD. We confirmed the reports and found that all treatments induced microtubule reorganization and PLD activation within the same time frame. PLD still was activated in microtubule-stabilized (taxol) and microtubule-depolymerized (oryzalin) situations, suggesting that PLD activation triggers microtubular reorganization and not vice versa. Exogenously applied water-soluble synthetic phosphatidic acid did not affect the microtubular cytoskeleton. Cell cycle studies revealed that n-butanol influenced not just interphase cortical microtubules but also those in the preprophase band and phragmoplast, but not those in the spindle structure. Cell growth and division were inhibited in the presence of n-butanol, whereas sec- and tert-butanol had no such effects. Using these novel insights, we propose a model for the mechanism by which PLD activation triggers microtubule reorganization in plant cells.

  5. Identifying functional reorganization of spelling networks: an individual peak probability comparison approach.

    Science.gov (United States)

    Purcell, Jeremy J; Rapp, Brenda

    2013-01-01

    Previous research has shown that damage to the neural substrates of orthographic processing can lead to functional reorganization during reading (Tsapkini et al., 2011); in this research we ask if the same is true for spelling. To examine the functional reorganization of spelling networks we present a novel three-stage Individual Peak Probability Comparison (IPPC) analysis approach for comparing the activation patterns obtained during fMRI of spelling in a single brain-damaged individual with dysgraphia to those obtained in a set of non-impaired control participants. The first analysis stage characterizes the convergence in activations across non-impaired control participants by applying a technique typically used for characterizing activations across studies: Activation Likelihood Estimate (ALE) (Turkeltaub et al., 2002). This method was used to identify locations that have a high likelihood of yielding activation peaks in the non-impaired participants. The second stage provides a characterization of the degree to which the brain-damaged individual's activations correspond to the group pattern identified in Stage 1. This involves performing a Mahalanobis distance statistics analysis (Tsapkini et al., 2011) that compares each of a control group's peak activation locations to the nearest peak generated by the brain-damaged individual. The third stage evaluates the extent to which the brain-damaged individual's peaks are atypical relative to the range of individual variation among the control participants. This IPPC analysis allows for a quantifiable, statistically sound method for comparing an individual's activation pattern to the patterns observed in a control group and, thus, provides a valuable tool for identifying functional reorganization in a brain-damaged individual with impaired spelling. Furthermore, this approach can be applied more generally to compare any individual's activation pattern with that of a set of other individuals.

  6. Tonotopic organization of human auditory association cortex.

    Science.gov (United States)

    Cansino, S; Williamson, S J; Karron, D

    1994-11-07

    Neuromagnetic studies of responses in human auditory association cortex for tone burst stimuli provide evidence for a tonotopic organization. The magnetic source image for the 100 ms component evoked by the onset of a tone is qualitatively similar to that of primary cortex, with responses lying deeper beneath the scalp for progressively higher tone frequencies. However, the tonotopic sequence of association cortex in three subjects is found largely within the superior temporal sulcus, although in the right hemisphere of one subject some sources may be closer to the inferior temporal sulcus. The locus of responses for individual subjects suggests a progression across the cortical surface that is approximately proportional to the logarithm of the tone frequency, as observed previously for primary cortex, with the span of 10 mm for each decade in frequency being comparable for the two areas.

  7. Where does TMS Stimulate the Motor Cortex?

    DEFF Research Database (Denmark)

    Bungert, Andreas; Antunes, André; Espenhahn, Svenja;

    2016-01-01

    Much of our knowledge on the physiological mechanisms of transcranial magnetic stimulation (TMS) stems from studies which targeted the human motor cortex. However, it is still unclear which part of the motor cortex is predominantly affected by TMS. Considering that the motor cortex consists...... of functionally and histologically distinct subareas, this also renders the hypotheses on the physiological TMS effects uncertain. We use the finite element method (FEM) and magnetic resonance image-based individual head models to get realistic estimates of the electric field induced by TMS. The field changes...... in different subparts of the motor cortex are compared with electrophysiological threshold changes of 2 hand muscles when systematically varying the coil orientation in measurements. We demonstrate that TMS stimulates the region around the gyral crown and that the maximal electric field strength in this region...

  8. Small High Schools and Student Achievement: Lottery-Based Evidence from New York City. NBER Working Paper No. 19576

    Science.gov (United States)

    Abdulkadiroglu, Atila; Hu, Weiwei; Pathak, Parag A.

    2013-01-01

    One of the most wideranging reforms in public education in the last decade has been the reorganization of large comprehensive high schools into small schools with roughly 100 students per grade. We use assignment lotteries embedded in New York City's high school match to estimate the effects of attendance at a new small high school on student…

  9. RTTN mutations link primary cilia function to organization of the human cerebral cortex

    NARCIS (Netherlands)

    S.K. Kia; E. Verbeek (Elly); M.P. Engelen (Erik); R. Schot (Rachel); R.A. Poot (Raymond); I.F.M. de Coo (René); M. Leguin (Maarten); C.J. Poulton (Cathryn); F. Pourfarzad, F. (Farzin); F.G. Grosveld (Frank); A. Brehm (António); M.C.Y. de Wit (Marie Claire); R. Oegema (Renske); W.B. Dobyns (William); F.W. Verheijen (Frans); G.M.S. Mancini (Grazia)

    2012-01-01

    textabstractPolymicrogyria is a malformation of the developing cerebral cortex caused by abnormal organization and characterized by many small gyri and fusion of the outer molecular layer. We have identified autosomal-recessive mutations in RTTN, encoding Rotatin, in individuals with bilateral diffu

  10. T Lymphocyte Activation Threshold and Membrane Reorganization Perturbations in Unique Culture Model

    Science.gov (United States)

    Adams, C. L.; Sams, C. F.

    2000-01-01

    Quantitative activation thresholds and cellular membrane reorganization are mechanisms by which resting T cells modulate their response to activating stimuli. Here we demonstrate perturbations of these cellular processes in a unique culture system that non-invasively inhibits T lymphocyte activation. During clinorotation, the T cell activation threshold is increased 5-fold. This increased threshold involves a mechanism independent of TCR triggering. Recruitment of lipid rafts to the activation site is impaired during clinorotation but does occur with increased stimulation. This study describes a situation in which an individual cell senses a change in its physical environment and alters its cell biological behavior.

  11. Dynamic reorganization of the actin cytoskeleton [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Gaëlle Letort

    2015-10-01

    Full Text Available Cellular processes, including morphogenesis, polarization, and motility, rely on a variety of actin-based structures. Although the biochemical composition and filament organization of these structures are different, they often emerge from a common origin. This is possible because the actin structures are highly dynamic. Indeed, they assemble, grow, and disassemble in a time scale of a second to a minute. Therefore, the reorganization of a given actin structure can promote the formation of another. Here, we discuss such transitions and illustrate them with computer simulations.

  12. Food related processes in the insular cortex

    Directory of Open Access Journals (Sweden)

    Sabine eFrank

    2013-08-01

    Full Text Available The insular cortex is a multimodal brain region with regional cytoarchitectonic differences indicating various functional specializations. As a multisensory neural node, the insular cortex integrates perception, emotion, interoceptive awareness, cognition, and gustation. Regarding the latter, predominantly the anterior part of the insular cortex is regarded as the primary taste cortex.In this review, we will specifically focus on the involvement of the insula in food processing and on multimodal integration of food-related items. Influencing factors of insular activation elicited by various foods range from calorie-content to the internal physiologic state, body mass index or eating behavior. Sensory perception of food-related stimuli including seeing, smelling, and tasting elicits increased activation in the anterior and mid-dorsal part of the insular cortex. Apart from the pure sensory gustatory processing, there is also a strong association with the rewarding/hedonic aspects of food items, which is reflected in higher insular activity and stronger connections to other reward-related areas. Interestingly, the processing of food items has been found to elicit different insular activation in lean compared to obese subjects and in patients suffering from an eating disorder (anorexia nervosa, bulimia nervosa. The knowledge of functional differences in the insular cortex opens up the opportunity for possible noninvasive treatment approaches for obesity and eating disorders. To target brain functions directly, real-time functional magnetic resonance imaging neurofeedback offers a state-of-the-art tool to learn to control the anterior insular cortex activity voluntarily. First evidence indicates that obese adults have an enhanced ability to regulate the anterior insular cortex.

  13. Motor Cortex Stimulation in Parkinson's Disease

    OpenAIRE

    Marisa De Rose; Giusy Guzzi; Domenico Bosco; Mary Romano; Serena Marianna Lavano; Massimiliano Plastino; Giorgio Volpentesta; Rosa Marotta; Angelo Lavano

    2012-01-01

    Motor Cortex Stimulation (MCS) is less efficacious than Deep Brain Stimulation (DBS) in Parkinson's disease. However, it might be proposed to patients excluded from DBS or unresponsive to DBS. Ten patients with advanced PD underwent unilateral MCS contralaterally to the worst clinical side. A plate electrode was positioned over the motor cortex in the epidural space through single burr hole after identification of the area with neuronavigation and neurophysiological tests. Clinical assessment...

  14. [Investigation on chemical constituents of processed products of Eucommiae Cortex].

    Science.gov (United States)

    Tao, Yi; Sheng, Chen; Li, Wei-dong; Cai, Bao-chang; Lu, Tu-lin

    2014-11-01

    According to the 2010 Chinese pharmacopeia, salt processed and charcoal processed Eucommiae Cortex were pre- pared. HPLC-DAD analysis of the content of the bark and leaf of Eucommiae Cortex showed that the bark of Eucommiae Cortex mainly contained lignans such as pinoresinol glucose and iridoid including genipin, geniposide, geniposidic acid, while the leaf of Eucommiae Cortex consisted of flavonoids such as quercetin and phenolic compound such as chlorogenic acid. The content of pinoresinol diglucoside in the bark of Eucommiae Cortex was about 18 times more than that in the leaf of Eucommiae Cortex. The content of pinoresinol diglucoside in salted and charcoal processed Eucommiae Cortex decreased approximately by 30% and 85%, respectively. The content of genipin, geniposide and geniposidic acid in the bark of Eucommiae Cortex was about 3 times, 23 times, 28 times more than that in the leaf of Eucommiae Cortex. The content of genipin, geniposide and geniposidic acid in salted Eucommiae Cortex were reduced by 25%, 40% and 40%, respectively. The content of genipin, geniposide and geniposidic acid in charcoal processed Eucommiae Cortex were reduced by 98%, 70%, 70%, respectively. The content of caffeic acid in bark of Eucommiae Cortex was about 3 times more than that in the leaf of Eucommiae Cortex. The content of caffeic acid was decreased by about 50% in the salted Eucommiae Cortex. While the content of caffeic acid in charcoal processed Eucommiae Cortex was decreased approximately 75%; the content of chlorogenic acid in bark of Eucommiae Cortex was about 1/6 of that in the leaf of Eucommiae Cortex. The content of chlorogenic acid in salted and charcoal processed Eucommiae Cortex decreased by 40% and 75%, respectively; the content of quercetin in bark of Eucommiae Cortex was only 1/40 of that in the leaf of Eucommiae Cortex. The content of quercetin in salted and charcoal processed Eucommiae Cortex were reduced by 60% and 50%, respectively.

  15. The adrenal cortex and life.

    Science.gov (United States)

    Vinson, Gavin P

    2009-03-05

    The template for our understanding of the physiological role of the adrenal cortex was set by Hans Selye, who demonstrated its key involvement in the response to stress, of whatever origin, and who also introduced the terms glucocorticoid and mineralocorticoid. Despite this, from the late 1940s on there was certainly general awareness of the multiple actions of glucocorticoids, including effects on the thymus and immune system, cardiovascular system, water balance, and the CNS. For these reasons, and perhaps because in the early studies of the actions of individual steroids there was less clear-cut difference between them, there was some initial resistance to the use of these terms. Today they are universal and unchallenged. It can be argued that, with respect to the glucocorticoids, this term colours our perception of their physiological importance, and may be misleading. By taking evidence from disease states, emphasis is placed on extreme conditions that do not necessarily reveal normal physiology. In particular, evidence for the role of glucocorticoid regulation of gluconeogenesis and blood glucose in the normal subject or animal is inconclusive. Similarly, while highly plausible theories explaining glucocorticoid actions on inflammation or the immune system as part of normal physiology have been presented, direct evidence to support them is hard to find. Under extreme conditions of chronic stress, the cumulative actions of glucocorticoids on insulin resistance or immunocompromise may indeed seem to be actually damaging. Two well-documented and long recognized situations create huge variation in glucocorticoid secretion. These are the circadian rhythm, and the acute response to mild stress, such as handling, in the rat. Neither of these can be adequately explained by the need for glucocorticoid action, as we currently understand it, particularly on carbohydrate metabolism or on the immune system. Perhaps we should re-examine other targets at the physiological

  16. The Role of Human Parietal Cortex in Attention Networks

    Science.gov (United States)

    Han, Shihui; Jiang, Yi; Gu, Hua; Rao, Hengyi; Mao, Lihua; Cui, Yong; Zhai, Renyou

    2004-01-01

    The parietal cortex has been proposed as part of the neural network for guiding spatial attention. However, it is unclear to what degree the parietal cortex contributes to the attentional modulations of activities of the visual cortex and the engagement of the frontal cortex in the attention network. We recorded behavioural performance and…

  17. Variation in the topography of the speech production cortex verified by cortical stimulation and high gamma activity.

    Science.gov (United States)

    Babajani-Feremi, Abbas; Rezaie, Roozbeh; Narayana, Shalini; Choudhri, Asim F; Fulton, Stephen P; Boop, Frederick A; Wheless, James W; Papanicolaou, Andrew C

    2014-12-17

    In this study, we have addressed the question of functional brain reorganization for language in the presence and absence of anatomical lesions in two patients with epilepsy using cortical stimulation mapping and high gamma (HG) activity in subdural grid recordings. In both, the expressive language cortex was defined as the cortical patch below the electrode(s) that when stimulated resulted in speech arrest, and during speech expression tasks generated HG activity. This patch fell within the borders of Broca's area, as defined anatomically, in the case of the patient with a lesion, but outside that area in the other, lesion-free patient. Such results highlight the necessity for presurgical language mapping in all cases of surgery involving the language-dominant hemisphere and suggest that HG activity during expressive language tasks can be informative and helpful in conjunction with cortical stimulation mapping for expressive language mapping.

  18. Fast-spiking GABA circuit dynamics in the auditory cortex predict recovery of sensory processing following peripheral nerve damage.

    Science.gov (United States)

    Resnik, Jennifer; Polley, Daniel B

    2017-03-21

    Cortical neurons remap their receptive fields and rescale sensitivity to spared peripheral inputs following sensory nerve damage. To address how these plasticity processes are coordinated over the course of functional recovery, we tracked receptive field reorganization, spontaneous activity, and response gain from individual principal neurons in the adult mouse auditory cortex over a 50-day period surrounding either moderate or massive auditory nerve damage. We related the day-by-day recovery of sound processing to dynamic changes in the strength of intracortical inhibition from parvalbumin-expressing (PV) inhibitory neurons. Whereas the status of brainstem-evoked potentials did not predict the recovery of sensory responses to surviving nerve fibers, homeostatic adjustments in PV-mediated inhibition during the first days following injury could predict the eventual recovery of cortical sound processing weeks later. These findings underscore the potential importance of self-regulated inhibitory dynamics for the restoration of sensory processing in excitatory neurons following peripheral nerve injuries.

  19. Fault reactivation by stress pattern reorganization in the Hyblean foreland domain of SE Sicily (Italy) and seismotectonic implications

    Science.gov (United States)

    Cultrera, Fabrizio; Barreca, Giovanni; Scarfì, Luciano; Monaco, Carmelo

    2015-10-01

    Between the October 2011 and the July 2012, several seismic swarms occurred in the Hyblean foreland domain of SE Sicily (Italy) along the Cavagrande Canyon, one of the most impressive fluvial incisions of Sicily. Despite the low magnitude of the events (main shock with M ~ 3.7), they represent the biggest strain release of the Hyblean area over the last 10 years. A careful waveform analysis of the earthquakes revealed that most of them form a family of "multiplets". These findings allow us to reconstruct the attitude of the accountable fault plane by interpolating their high-precision 3D location parameters into a GIS platform. A detailed morpho-structural analysis, performed at the ideal updip projection of the modeled plane, showed that during the Middle-Late Pleistocene the epicentral area has been deformed by a belt of extensional faults, a segment of which matches well with the computer-generated surface. Despite the field evidence, computed focal solutions support contrasting strike-slip kinematics on the same fault plane, clearly indicating a dextral shearing on this pre-existing normal fault. The seismic swarms nucleated on a small rupture area along a ~ 10 km long, NW-SE trending fault segment, that could be able to generate M ~ 6 earthquakes. Following our analysis and looking at seismicity distribution in the SE portion of Hyblean area, we assess that a stress pattern reorganization occurred all over the Hyblean foreland between the Late Pleistocene and present-day. Change in the trajectory of the max stress axes (from vertical to horizontal) seems to have involved a pre-existing large-scale fault configuration with considerable seismotectonic implications.

  20. Single-Molecule Discrimination within Dendritic Spines of Discrete Perisynaptic Sites of Actin Filament Assembly Driving Postsynaptic Reorganization

    Science.gov (United States)

    Blanpied, Thomas A.

    2013-03-01

    In the brain, the strength of synaptic transmission between neurons is principally set by the organization of proteins within the receptive, postsynaptic cell. Synaptic strength at an individual site of contact can remain remarkably stable for months or years. However, it also can undergo diverse forms of plasticity which change the strength at that contact independent of changes to neighboring synapses. Such activity-triggered neural plasticity underlies memory storage and cognitive development, and is disrupted in pathological physiology such as addiction and schizophrenia. Much of the short-term regulation of synaptic plasticity occurs within the postsynaptic cell, in small subcompartments surrounding the synaptic contact. Biochemical subcompartmentalization necessary for synapse-specific plasticity is achieved in part by segregation of synapses to micron-sized protrusions from the cell called dendritic spines. Dendritic spines are heavily enriched in the actin cytoskeleton, and regulation of actin polymerization within dendritic spines controls both basal synaptic strength and many forms of synaptic plasticity. However, understanding the mechanism of this control has been difficult because the submicron dimensions of spines limit examination of actin dynamics in the spine interior by conventional confocal microscopy. To overcome this, we developed single-molecule tracking photoactivated localization microscopy (smtPALM) to measure the movement of individual actin molecules within living spines. This revealed inward actin flow from broad areas of the spine plasma membrane, as well as a dense central core of heterogeneous filament orientation. The velocity of single actin molecules along filaments was elevated in discrete regions within the spine, notably near the postsynaptic density but surprisingly not at the endocytic zone which is involved in some forms of plasticity. We conclude that actin polymerization is initiated at many well-separated foci within

  1. Compensatory plasticity and cross-modal reorganization following early visual deprivation

    DEFF Research Database (Denmark)

    Kupers, Ron; Ptito, Maurice

    2014-01-01

    For human and non-human primates, vision is one of the most privileged sensory channels used to interact with the environment. The importance of vision is strongly embedded in the organization of the primate brain as about one third of its cortical surface is involved in visual functions...... that take place not only in the visually deprived cortex but also in other brain areas. These studies have further shown that the visually deprived cortex becomes responsive to a wide variety of non-visual sensory inputs. Recent studies even showed a role of the visually deprived cortex in cognitive...... processes. At the behavioral level, increases in acuity for auditory and tactile processes have been reported. The study of the congenitally blind brain also offers a unique model to gain better insights into the functioning of the normal sighted brain and to understand to what extent visual experience...

  2. VAMP-7 links granule exocytosis to actin reorganization during platelet activation.

    Science.gov (United States)

    Koseoglu, Secil; Peters, Christian G; Fitch-Tewfik, Jennifer L; Aisiku, Omozuanvbo; Danglot, Lydia; Galli, Thierry; Flaumenhaft, Robert

    2015-07-30

    Platelet activation results in profound morphologic changes accompanied by release of granule contents. Recent evidence indicates that fusion of granules with the plasma membrane during activation provides auxiliary membrane to cover growing actin structures. Yet little is known about how membrane fusion is coupled with actin reorganization. Vesicle-associated membrane protein (VAMP)-7 is found on platelet vesicles and possesses an N-terminal longin domain capable of linking exocytosis to cytoskeletal remodeling. We have evaluated platelets from VAMP-7(-/-) mice to determine whether this VAMP isoform contributes to granule release and platelet spreading. VAMP-7(-/-) platelets demonstrated a partial defect in dense granule exocytosis and impaired aggregation. α Granule exocytosis from VAMP-7(-/-) platelets was diminished both in vitro and in vivo during thrombus formation. Consistent with a role of VAMP-7 in cytoskeletal remodeling, spreading on matrices was decreased in VAMP-7(-/-) platelets compared to wild-type controls. Immunoprecipitation of VAMP-7 revealed an association with VPS9-domain ankyrin repeat protein (VARP), an adaptor protein that interacts with both membrane-bound and cytoskeleton proteins and with Arp2/3. VAMP-7, VARP, and Arp2/3 localized to the platelet periphery during spreading. These studies demonstrate that VAMP-7 participates in both platelet granule secretion and spreading and suggest a mechanism whereby VAMP-7 links granule exocytosis with actin reorganization.

  3. Cerebral Functional Reorganization in Ischemic Stroke after Repetitive Transcranial Magnetic Stimulation: An fMRI Study.

    Science.gov (United States)

    Li, Jing; Zhang, Xue-Wei; Zuo, Zhen-Tao; Lu, Jie; Meng, Chun-Ling; Fang, Hong-Ying; Xue, Rong; Fan, Yong; Guan, Yu-Zhou; Zhang, Wei-Hong

    2016-12-01

    Our study aimed to figure out brain functional reorganization evidence after repetitive transcranial magnetic stimulation (rTMS) using the resting-state functional magnetic resonance imaging (rsfMRI). Twelve patients with unilateral subcortex lesion in the middle cerebral artery territory were recruited. Seven of them received a 10-day rTMS treatment beginning at about 5 days after stroke onset. The remaining five received sham treatment. RsfMRI and motor functional scores were obtained before and after rTMS or sham rTMS. The rTMS group showed motor recovery according to the behavioral testing scores, while there was no significant difference of motor functional scores in the sham group before and after the sham rTMS. It proved that rTMS facilitates motor recovery of early ischemic stroke patients. Compared with the sham, the rTMS treatment group achieved increased functional connectivity (FC) between ipsilesional M1 and contralesional M1, supplementary motor area, bilateral thalamus, and contralesional postcentral gyrus. And decreased FC was found between ipsilesional M1 and ipsilesional M1, postcentral gyrus and inferior and middle frontal gyrus. Increased or decreased FC detected by rsfMRI is an important finding to understand the mechanism of brain functional reorganization. The rTMS treatment is a promising therapeutic approach to facilitate motor rehabilitation for early stroke patients. © 2016 John Wiley & Sons Ltd.

  4. Dynamic functional reorganizations and relationship with working memory performance in healthy aging.

    Directory of Open Access Journals (Sweden)

    Roser eSala-Llonch

    2012-06-01

    Full Text Available In recent years, several theories have been proposed in attempts to identify the neural mechanisms underlying successful cognitive aging. Old subjects show increased neural activity during the performance of tasks, mainly in prefrontal areas, which is interpreted as a compensatory mechanism linked to functional brain efficiency. Moreover, resting-state studies have concluded that elders show disconnection or disruption of large-scale functional networks. We used functional MRI during resting-state and a verbal n-back task with different levels of memory load in a cohort of young and old healthy adults to identify patterns of networks associated with working memory and brain default mode. We found that the disruption of resting-state networks in the elderly coexists with task-related overactivations of certain brain areas and with reorganizations within these functional networks. Moreover, elders who were able to activate additional areas and to recruit a more bilateral frontal pattern within the task-related network achieved successful performance on the task. We concluded that the balanced and plastic reorganization of brain networks underlies successful cognitive aging. This observation allows the integration of several theories that have been proposed to date regarding the aging brain.

  5. Congenital blindness is associated with large-scale reorganization of anatomical networks.

    Science.gov (United States)

    Hasson, Uri; Andric, Michael; Atilgan, Hicret; Collignon, Olivier

    2016-03-01

    Blindness is a unique model for understanding the role of experience in the development of the brain's functional and anatomical architecture. Documenting changes in the structure of anatomical networks for this population would substantiate the notion that the brain's core network-level organization may undergo neuroplasticity as a result of life-long experience. To examine this issue, we compared whole-brain networks of regional cortical-thickness covariance in early blind and matched sighted individuals. This covariance is thought to reflect signatures of integration between systems involved in similar perceptual/cognitive functions. Using graph-theoretic metrics, we identified a unique mode of anatomical reorganization in the blind that differed from that found for sighted. This was seen in that network partition structures derived from subgroups of blind were more similar to each other than they were to partitions derived from sighted. Notably, after deriving network partitions, we found that language and visual regions tended to reside within separate modules in sighted but showed a pattern of merging into shared modules in the blind. Our study demonstrates that early visual deprivation triggers a systematic large-scale reorganization of whole-brain cortical-thickness networks, suggesting changes in how occipital regions interface with other functional networks in the congenitally blind.

  6. Corporate reorganization: the last gasp or last clear chance for the tax-exempt, nonprofit hospital?

    Science.gov (United States)

    Horwitz, M

    1988-01-01

    The current revolution in health care organization and financing, increased competition, and a retrenching of industry from its commitments to expansion of health care benefits challenge the nonprofit hospital's existence as a viable entity. Hospital governing boards and administrators have turned to corporate reorganization in order to maintain their financial position and to continue to serve their communities. This Article examines the not-for-profit concept and the problems facing nonprofit hospitals. It reviews the pros and cons of reorganization and the for-profit/nonprofit controversy. It questions whether the hybridization of the hospital results in a stronger or weaker species and discusses the possible effects of the newly structured entity on the quality and delivery of health care. Finally, the Article suggests that the nonprofit hospital may survive only by a continued commitment to societal and communal values, to service rather than to profit; that this commitment is adequate justificaton for the preservation of the nonprofit system, and its preservation will reinforce and strengthen the concept.

  7. Bankruptcy Reorganization in China and the United States:Cautions for the Comparativist

    Institute of Scientific and Technical Information of China (English)

    William J.Woodward

    2010-01-01

    <正>In the late 1930’s Americans developed their first comprehensive law of bankruptcy reorganization.In larger cases,that law provided for the appointment of a trustee and seizure of control of the business from the business’s prior control group.In 1978,that was all changed;the prototype in the United States now leaves the "debtor in possession" charged with operating the business for the benefit of the business’s creditors.In this and many other ways,America’s law differs substantially from China’s relatively-new bankruptcy law.This article briefly looks at some of the stronger differences between the two systems and gives some background to how and why the American system evolved from the older model to the newer one.While we might easily identify many fundamental differences between the American and Chinese systems,drawing normative policy recommendations from those differences is a much more challenging task.One might,of course,be tempted to do so anyway.But the differing cultural,legal,and economic contexts within which bankruptcy reorganization exists suggests that one so tempted should proceed very cautiously and,perhaps,with an extra measure of modesty as well.

  8. Desiccation tolerance in the tardigrade Richtersius coronifer relies on muscle mediated structural reorganization.

    Science.gov (United States)

    Halberg, Kenneth Agerlin; Jørgensen, Aslak; Møbjerg, Nadja

    2013-01-01

    Life unfolds within a framework of constraining abiotic factors, yet some organisms are adapted to handle large fluctuations in physical and chemical parameters. Tardigrades are microscopic ecdysozoans well known for their ability to endure hostile conditions, such as complete desiccation--a phenomenon called anhydrobiosis. During dehydration, anhydrobiotic animals undergo a series of anatomical changes. Whether this reorganization is an essential regulated event mediated by active controlled processes, or merely a passive result of the dehydration process, has not been clearly determined. Here, we investigate parameters pivotal to the formation of the so-called "tun", a state that in tardigrades and rotifers marks the entrance into anhydrobiosis. Estimation of body volume in the eutardigrade Richtersius coronifer reveals an 87 % reduction in volume from the hydrated active state to the dehydrated tun state, underlining the structural stress associated with entering anhydrobiosis. Survival experiments with pharmacological inhibitors of mitochondrial energy production and muscle contractions show that i) mitochondrial energy production is a prerequisite for surviving desiccation, ii) uncoupling the mitochondria abolishes tun formation, and iii) inhibiting the musculature impairs the ability to form viable tuns. We moreover provide a comparative analysis of the structural changes involved in tun formation, using a combination of cytochemistry, confocal laser scanning microscopy and 3D reconstructions as well as scanning electron microscopy. Our data reveal that the musculature mediates a structural reorganization vital for anhydrobiotic survival, and furthermore that maintaining structural integrity is essential for resumption of life following rehydration.

  9. Desiccation tolerance in the tardigrade Richtersius coronifer relies on muscle mediated structural reorganization.

    Directory of Open Access Journals (Sweden)

    Kenneth Agerlin Halberg

    Full Text Available Life unfolds within a framework of constraining abiotic factors, yet some organisms are adapted to handle large fluctuations in physical and chemical parameters. Tardigrades are microscopic ecdysozoans well known for their ability to endure hostile conditions, such as complete desiccation--a phenomenon called anhydrobiosis. During dehydration, anhydrobiotic animals undergo a series of anatomical changes. Whether this reorganization is an essential regulated event mediated by active controlled processes, or merely a passive result of the dehydration process, has not been clearly determined. Here, we investigate parameters pivotal to the formation of the so-called "tun", a state that in tardigrades and rotifers marks the entrance into anhydrobiosis. Estimation of body volume in the eutardigrade Richtersius coronifer reveals an 87 % reduction in volume from the hydrated active state to the dehydrated tun state, underlining the structural stress associated with entering anhydrobiosis. Survival experiments with pharmacological inhibitors of mitochondrial energy production and muscle contractions show that i mitochondrial energy production is a prerequisite for surviving desiccation, ii uncoupling the mitochondria abolishes tun formation, and iii inhibiting the musculature impairs the ability to form viable tuns. We moreover provide a comparative analysis of the structural changes involved in tun formation, using a combination of cytochemistry, confocal laser scanning microscopy and 3D reconstructions as well as scanning electron microscopy. Our data reveal that the musculature mediates a structural reorganization vital for anhydrobiotic survival, and furthermore that maintaining structural integrity is essential for resumption of life following rehydration.

  10. THE HIGHLY DEVELOPED INFORMATION AND EDUCATION ENVIRONMENT AS A PRECONDITION OF EDUCATIONAL SYSTEM REORGANIZATION

    Directory of Open Access Journals (Sweden)

    Y. K. Khenner

    2014-01-01

    Full Text Available The paper regards the development of the information and education environment of Russian universities as an important condition for successful reorganization of higher education. Taking as an example one of theUSuniversities, the author demonstrates the capacity of information education environment and its impact on the multilevel educational process. The comparative analysis of the existing information education environments of Russian an American universities reveals that such effective improvements as increasing number of students working on the individual curricula,__ implementation of the learning outcome monitoring, inclusive education, etc require immediate and substantial development of the information education environment of Russian universities. Both the development level and informational content of the environment in question remain unsatisfactory due to the financial, economic and staff related reasons. Consequently, the higher school reorganization is lagging behind retarded by the lack of synchronization between the attempts to improve the education quality and competitiveness on the one hand, and insufficient level of the information education environment characteristic of Russian universities on the other hand.

  11. Myeloperoxidase modulates human platelet aggregation via actin cytoskeleton reorganization and store-operated calcium entry

    Directory of Open Access Journals (Sweden)

    Irina V. Gorudko

    2013-07-01

    Myeloperoxidase (MPO is a heme-containing enzyme released from activated leukocytes into the extracellular space during inflammation. Its main function is the production of hypohalous acids that are potent oxidants. MPO can also modulate cell signaling and inflammatory responses independently of its enzymatic activity. Because MPO is regarded as an important risk factor for cardiovascular diseases associated with increased platelet activity, we studied the effects of MPO on human platelet functional properties. Laser scanning confocal microscopy was used to reveal carbohydrate-independent MPO binding to human platelet membrane. Adding MPO to platelets did not activate their aggregation under basal conditions (without agonist. In contrast, MPO augmented agonist-induced platelet aggregation, which was not prevented by MPO enzymatic activity inhibitors. It was found that exposure of platelets to MPO leads to actin cytoskeleton reorganization and an increase in their elasticity. Furthermore, MPO evoked a rise in cytosolic Ca2+ through enhancement of store-operated Ca2+ entry (SOCE. Together, these findings indicate that MPO is not a direct agonist but rather a mediator that binds to human platelets, induces actin cytoskeleton reorganization and affects the mechanical stiffness of human platelets, resulting in potentiating SOCE and agonist-induced human platelet aggregation. Therefore, an increased activity of platelets in vascular disease can, at least partly, be provided by MPO elevated concentrations.

  12. Progressive brain damage, synaptic reorganization and NMDA activation in a model of epileptogenic cortical dysplasia.

    Directory of Open Access Journals (Sweden)

    Francesca Colciaghi

    Full Text Available Whether severe epilepsy could be a progressive disorder remains as yet unresolved. We previously demonstrated in a rat model of acquired focal cortical dysplasia, the methylazoxymethanol/pilocarpine - MAM/pilocarpine - rats, that the occurrence of status epilepticus (SE and subsequent seizures fostered a pathologic process capable of modifying the morphology of cortical pyramidal neurons and NMDA receptor expression/localization. We have here extended our analysis by evaluating neocortical and hippocampal changes in MAM/pilocarpine rats at different epilepsy stages, from few days after onset up to six months of chronic epilepsy. Our findings indicate that the process triggered by SE and subsequent seizures in the malformed brain i is steadily progressive, deeply altering neocortical and hippocampal morphology, with atrophy of neocortex and CA regions and progressive increase of granule cell layer dispersion; ii changes dramatically the fine morphology of neurons in neocortex and hippocampus, by increasing cell size and decreasing both dendrite arborization and spine density; iii induces reorganization of glutamatergic and GABAergic networks in both neocortex and hippocampus, favoring excitatory vs inhibitory input; iv activates NMDA regulatory subunits. Taken together, our data indicate that, at least in experimental models of brain malformations, severe seizure activity, i.e., SE plus recurrent seizures, may lead to a widespread, steadily progressive architectural, neuronal and synaptic reorganization in the brain. They also suggest the mechanistic relevance of glutamate/NMDA hyper-activation in the seizure-related brain pathologic plasticity.

  13. Large extents of intensive land use limit community reorganization during climate warming.

    Science.gov (United States)

    Oliver, Tom H; Gillings, Simon; Pearce-Higgins, James W; Brereton, Tom; Crick, Humphrey Q P; Duffield, Simon J; Morecroft, Michael D; Roy, David B

    2017-06-01

    Climate change is increasingly altering the composition of ecological communities, in combination with other environmental pressures such as high-intensity land use. Pressures are expected to interact in their effects, but the extent to which intensive human land use constrains community responses to climate change is currently unclear. A generic indicator of climate change impact, the community temperature index (CTI), has previously been used to suggest that both bird and butterflies are successfully 'tracking' climate change. Here, we assessed community changes at over 600 English bird or butterfly monitoring sites over three decades and tested how the surrounding land has influenced these changes. We partitioned community changes into warm- and cold-associated assemblages and found that English bird communities have not reorganized successfully in response to climate change. CTI increases for birds are primarily attributable to the loss of cold-associated species, whilst for butterflies, warm-associated species have tended to increase. Importantly, the area of intensively managed land use around monitoring sites appears to influence these community changes, with large extents of intensively managed land limiting 'adaptive' community reorganization in response to climate change. Specifically, high-intensity land use appears to exacerbate declines in cold-adapted bird and butterfly species, and prevent increases in warm-associated birds. This has broad implications for managing landscapes to promote climate change adaptation. © 2017 John Wiley & Sons Ltd.

  14. Experimental evidence of landscape reorganization under changing external forcing: implications to climate-driven knickpoints

    Science.gov (United States)

    Singh, Arvind; Tejedor, Alejandro; Grimaud, Jean-Louis; Foufoula-Georgiou, Efi

    2017-04-01

    Understanding and quantifying geomorphic and topologic re-organization of landscape in response to changing climatic or tectonic forcing is of scientific and practical interest. Although several studies have addressed the large-scale response (e.g., change in mean relief), studies on the smaller-scale drainage pattern re-organization and quantification of landscape vulnerability to the timing, magnitude, and frequency of changing forcing are lacking. To that goal, a series of controlled laboratory experiments were conducted to study the effect of changing precipitation patterns on landscape evolution at the short and long-time scales. High resolution digital elevation (DEM) both in space and time were measured for a range of rainfall patterns and uplift rates. Results from our study show a distinct signature of the precipitation increase on the probabilistic and geometrical structure of landscape features, evident in widening and deepening of channels and valleys, change in drainage patterns within sub-basins and change in the space-time structure of erosional and depositional events. A spatially explicit analysis of the locus of these erosional and depositional events show an acceleration of erosion in the hillslopes when the rainfall intensity is increased, while the incision in fluvial channels is slowed down exhibiting a sediment-flux dependent behavior. Finally, we document the changes in the longitudinal river profiles with increasing precipitation intensity, revealing the formation of knickpoints at certain confluences where large discontinuities in the ratio Qs/Qw are observed.

  15. Solvent Reorganization Energy of Intramolecular Electron Transfer in Peptides Involving Tryptophan and Tyrosine

    Institute of Scientific and Technical Information of China (English)

    ZHAO Ying-Yi; MA Jian-Yi; ZHAO Xiao-Jun; LI Xiang-Yuan

    2008-01-01

    Intramolecular electron transfer(ET)from tyrosine to tryptophan within peptide Trp-(Pro),-Tyr(n=1,2)has been investigated by ab initio calculation associated with a proper consideration of solvent effect by a continuum model.After geometry optimizations of the charge-localized reactant and product,double-well potentials have been constructed by adopting the linear reaction coordinate.The transition state has been determined by finding the crossing point of the potential energy curves.The realistic ET reaction was found complicated in polar solvent,hence the solvent reorganization energy of the electron transfer has received especial attention in this work.Apply-ing the nonequilibrium solvation procedure implemented based on the polarizable continuum model by the authors,the solvent reorganization energy was estimated to be 87.36 kJ/mol for the ET in Trp-Pro-Tyr system and 105.80 kJ/mol for Trp-(Pro)2-Tyr.

  16. Zyxin regulates endothelial von Willebrand factor secretion by reorganizing actin filaments around exocytic granules

    Science.gov (United States)

    Han, Xiaofan; Li, Pin; Yang, Zhenghao; Huang, Xiaoshuai; Wei, Guoqin; Sun, Yujie; Kang, Xuya; Hu, Xueting; Deng, Qiuping; Chen, Liangyi; He, Aibin; Huo, Yingqing; Li, Dong; Betzig, Eric; Luo, Jincai

    2017-01-01

    Endothelial exocytosis of Weibel–Palade body (WPB) is one of the first lines of defence against vascular injury. However, the mechanisms that control WPB exocytosis in the final stages (including the docking, priming and fusion of granules) are poorly understood. Here we show that the focal adhesion protein zyxin is crucial in this process. Zyxin downregulation inhibits the secretion of von Willebrand factor (VWF), the most abundant cargo in WPBs, from human primary endothelial cells (ECs) induced by cAMP agonists. Zyxin-deficient mice exhibit impaired epinephrine-stimulated VWF release, prolonged bleeding time and thrombosis, largely due to defective endothelial secretion of VWF. Using live-cell super-resolution microscopy, we visualize previously unappreciated reorganization of pre-existing actin filaments around WPBs before fusion, dependent on zyxin and an interaction with the actin crosslinker α-actinin. Our findings identify zyxin as a physiological regulator of endothelial exocytosis through reorganizing local actin network in the final stage of exocytosis. PMID:28256511

  17. Data Reorganization for Optimal Time Series Data Access, Analysis, and Visualization

    Science.gov (United States)

    Rui, H.; Teng, W. L.; Strub, R.; Vollmer, B.

    2012-12-01

    visualization that contribute to knowledge discovery from large science data sets, the GES DISC recently begun a NASA ACCESS-funded project to, in part, optimally reorganize selected large data sets for access and use by the hydrological user community. This presentation discusses the following aspects of the project: (1) explorations of approaches, such as database and file system; (2) findings for each approach, such as limitations and concerns, and pros and cons; (3) implementation of reorganizing data via the file system approach, including data processing (parameter and spatial subsetting), metadata and file structure of reorganized time series data (true "Data Rod," single variable, single grid point, and entire data range per file), and production and quality control. The reorganized time series data will be integrated into several broadly used data tools, such as NASA Giovanni and those provided by CUAHSI HIS (http://his.cuahsi.org/) and EPA BASINS (http://water.epa.gov/scitech/datait/models/basins/), as well as accessible via direct FTP, along with documentation and sample reading software. The data reorganization is initially, as part of the project, applied to selected popular hydrology-related parameters, with other parameters to be added, as resources permit.

  18. Perirhinal cortex and temporal lobe epilepsy

    Directory of Open Access Journals (Sweden)

    Giuseppe eBiagini

    2013-08-01

    Full Text Available The perirhinal cortex – which is interconnected with several limbic structures and is intimately involved in learning and memory - plays major roles in pathological processes such as the kindling phenomenon of epileptogenesis and the spread of limbic seizures. Both features may be relevant to the pathophysiology of mesial temporal lobe epilepsy that represents the most refractory adult form of epilepsy with up to 30% of patients not achieving adequate seizure control. Compared to other limbic structures such as the hippocampus or the entorhinal cortex, the perirhinal area remains understudied and, in particular, detailed information on its dysfunctional characteristics remains scarce; this lack of information may be due to the fact that the perirhinal cortex is not grossly damaged in mesial temporal lobe epilepsy and in models mimicking this epileptic disorder. However, we have recently identified in pilocarpine-treated epileptic rats the presence of selective losses of interneuron subtypes along with increased synaptic excitability. In this review we: (i highlight the fundamental electrophysiological properties of perirhinal cortex neurons; (ii briefly stress the mechanisms underlying epileptiform synchronization in perirhinal cortex networks following epileptogenic pharmacological manipulations; and (iii focus on the changes in neuronal excitability and cytoarchitecture of the perirhinal cortex occurring in the pilocarpine model of mesial temporal lobe epilepsy. Overall, these data indicate that perirhinal cortex networks are hyperexcitable in an animal model of temporal lobe epilepsy, and that this condition is associated with a selective cellular damage that is characterized by an age-dependent sensitivity of interneurons to precipitating injuries, such as status epilepticus.

  19. Deep prepiriform cortex kindling and amygdala interactions.

    Science.gov (United States)

    Zhao, D Y; Moshé, S L

    1987-03-01

    The deep prepiriform cortex (DPC) has been recently suggested to be a crucial epileptogenic site in the rat brain. We investigated the susceptibility of the DPC to the development of electrical kindling as compared to that of the superficial prepiriform cortex (SPC) and amygdala as well as the transfer interactions between the two prepiriform sites and amygdala. Adult rats with electrodes implanted in the right prepiriform cortex (DPC or SPC) and left amygdala were divided into a DPC-amygdala and SPC-amygdala group while a third group consisted of rats with electrodes implanted in the ipsilateral DPC and amygdala. Within each group the rats were initially kindled from one site selected randomly and then rekindled from the other site. Both DPC and SPC were as sensitive to the development of kindling as the amygdala. The behavioral seizures elicited with DPC or SPC primary kindling were identical to those induced by amygdala kindling. Initial DPC kindling facilitated the development of kindling from either ipsilateral or contralateral amygdala with the ipsilateral transfer being significantly more potent than the contralateral. SPC kindling also facilitated the development of contralateral amygdala kindling but was less effective than DPC kindling. On the other hand, amygdala kindling did not facilitate contralateral SPC or DPC kindling although it transferred to the ipsilateral DPC. These results indicate that the prepiriform cortex can be readily kindled but not faster than the amygdala and that there are unequal kindling transfer interactions between prepiriform cortex and amygdala.

  20. Motor cortex neuroplasticity following brachial plexus transfer

    Directory of Open Access Journals (Sweden)

    Stefan eDimou

    2013-08-01

    Full Text Available In the past decade, research has demonstrated that cortical plasticity, once thought only to exist in the early stages of life, does indeed continue on into adulthood. Brain plasticity is now acknowledged as a core principle of brain function and describes the ability of the central nervous system to adapt and modify its structural organization and function as an adaptive response to functional demand. In this clinical case study we describe how we used neuroimaging techniques to observe the functional topographical expansion of a patch of cortex along the sensorimotor cortex of a 27 year-old woman following brachial plexus transfer surgery to re-innervate her left arm. We found bilateral activations present in the thalamus, caudate, insula as well as across the sensorimotor cortex during an elbow flex motor task. In contrast we found less activity in the sensorimotor cortex for a finger tap motor task in addition to activations lateralised to the left inferior frontal gyrus and thalamus and bilaterally for the insula. From a pain perspective the patient who had experienced extensive phantom limb pain before surgery found these sensations were markedly reduced following transfer of the right brachial plexus to the intact left arm. Within the context of this clinical case the results suggest that functional improvements in limb mobility are associated with increased activation in the sensorimotor cortex as well as reduced phantom limb pain.

  1. [Prefrontal cortex in memory and attention processes].

    Science.gov (United States)

    Allegri, R F; Harris, P

    The role of the prefrontal cortex still remains poorly understood. Only after 1970, the functions of the frontal lobes have been conceptualized from different points of view (behaviorism, cognitivism). Recently,different parallel circuits connecting discrete cortical and subcortical regions of the frontal lobes have been described. Three of these circuits are the most relevant to understanding of behavior: the dorsolateral prefrontal circuit, that mediates executive behavior; the orbitofrontal prefrontal circuit, mediating social behavior, and the medial frontal circuit, involved in motivation. Damage to the frontal cortex impairs planning, problem solving, reasoning, concept formation, temporal ordering of stimuli, estimation, attention, memory search, maintaining information in working memory, associative learning,certain forms of skilled motor activities, image generation and manipulation of the spatial properties of a stimulus, metacognitive thinking, and social cognition. Several theories have been proposed to explain the functions of the prefrontal cortex. Currently,the most influential cognitive models are: the Norman and Shallice supervisory attentional system, involved in non-routine selection; the Baddeley working memory model with the central executive as a supervisory controlling system, in which impairment leads to a 'dysexecutive syndrome'; and the Grafman's model of managerial knowledge units, stored as macrostructured information in the frontal cortex. The prefrontal cortex is essential for attentional control, manipulation of stored knowledge and modulation of complex actions, cognition, emotion and behavior.

  2. The Factors and Transversal Reorganizations Principles of Romanian Textile Industry Enterprises using Activity-Based Costing Method

    Directory of Open Access Journals (Sweden)

    Sorinel Capusneanu

    2007-04-01

    Full Text Available This article describes the factors and the principles of transversal reorganization of the enterprises from the Romanian textile industry by adapting the Activity-Based Costing method (ABC to its specific. There are presented and analyzed the real possibilities of reorganization of the enterprises in Romania by elaboration of methodological phases that will be covered until the implementation of their transversal organization. Are we ready to adapt the Activity-Based Costing method to the specific of the Romanian textile industry and not only? Here is the question whose response we will find in this article.

  3. Language learning and brain reorganization in a 3.5-year-old child with left perinatal stroke revealed using structural and functional connectivity.

    Science.gov (United States)

    François, Clément; Ripollés, Pablo; Bosch, Laura; Garcia-Alix, Alfredo; Muchart, Jordi; Sierpowska, Joanna; Fons, Carme; Solé, Jorgina; Rebollo, Monica; Gaitán, Helena; Rodriguez-Fornells, Antoni

    2016-04-01

    Brain imaging methods have contributed to shed light on the possible mechanisms of recovery and cortical reorganization after early brain insult. The idea that a functional left hemisphere is crucial for achieving a normalized pattern of language development after left perinatal stroke is still under debate. We report the case of a 3.5-year-old boy born at term with a perinatal ischemic stroke of the left middle cerebral artery, affecting mainly the supramarginal gyrus, superior parietal and insular cortex extending to the precentral and postcentral gyri. Neurocognitive development was assessed at 25 and 42 months of age. Language outcomes were more extensively evaluated at the latter age with measures on receptive vocabulary, phonological whole-word production and linguistic complexity in spontaneous speech. Word learning abilities were assessed using a fast-mapping task to assess immediate and delayed recall of newly mapped words. Functional and structural imaging data as well as a measure of intrinsic connectivity were also acquired. While cognitive, motor and language levels from the Bayley Scales fell within the average range at 25 months, language scores were below at 42 months. Receptive vocabulary fell within normal limits but whole word production was delayed and the child had limited spontaneous speech. Critically, the child showed clear difficulties in both the immediate and delayed recall of the novel words, significantly differing from an age-matched control group. Neuroimaging data revealed spared classical cortical language areas but an affected left dorsal white-matter pathway together with right lateralized functional activations. In the framework of the model for Social Communication and Language Development, these data confirm the important role of the left arcuate fasciculus in understanding and producing morpho-syntactic elements in sentences beyond two word combinations and, most importantly, in learning novel word-referent associations, a

  4. Coherent theta oscillations and reorganization of spike timing in the hippocampal-prefrontal network upon learning

    NARCIS (Netherlands)

    Benchenane, K.; Peyrache, A.; Khamassi, M.; Tierney, P.L.; Gioanni, Y.; Battaglia, F.P.; Wiener, S.I.

    2010-01-01

    To study the interplay between hippocampus and medial prefrontal cortex (Pfc) and its importance for learning and memory consolidation, we measured the coherence in theta oscillations between these two structures in rats learning new rules on a Y maze. Coherence peaked at the choice point, most stro

  5. Somatotopic reorganization of hand representation in bilateral arm amputees with or without special foot movement skill.

    Science.gov (United States)

    Yu, Xiao Jing; He, Hong Jian; Zhang, Qiao Wei; Zhao, Feng; Zee, Chi Shing; Zhang, Shi Zheng; Gong, Xiang Yang

    2014-02-10

    Bilateral arm amputees usually are excellent foot users. To explore the plasticity of the primary motor cortex in upper-extremities amputees and to determine if the acquisition of special foot movement skill is related with the bilateral hand amputation, we studied the primary motor cortex by using combined task and resting state functional magnetic resonance imaging (fMRI). We investigated 6 bilateral arm amputees with or without special foot movement skill. In the task fMRI study, we found that toe tapping of all the amputees activated the bilateral hand area, including cases without special foot skill. In addition, cases without special foot skill mainly activated the precentral gyrus, which differed from those with more adept foot motor skill who activated both the precentral and postcentral gyri. To further understand the plasticity of the hand area, the resting state functional connectivity was investigated between the foot and hand regions. One-tailed two-sample t-test suggested that the connections between two areas became significantly stronger in the amputee group. Our study demonstrates that hand region of the cortex does not remain 'silent' after bilateral arm amputation, but rather is recruited by other modalities such as adjacent or nonadjacent cortexes to process motor information in a functionally relevant manner. From the data presented, it seems that the bilateral arm amputees have a strong potential to develop new skills in their remaining extremities and practice may further enhance this potential.

  6. Corporate debts ad credit performance under the new mechanism of reorganization of the Russian banks

    Directory of Open Access Journals (Sweden)

    Sergey A. Andryushin

    2017-09-01

    Full Text Available Objective to explore the dynamics and factors of formation of corporate debts the characteristics of low credit activity of the Russian banks and regulation of liquidity deficit of enterprises under the new reorganization mechanism in the Russian banking sector. Methods systematic approach to the cognition of economic phenomena which allows to study them in their dynamic development taking into account the influence of various environmental factors. The systematic approach determined selection of specific research methods empirical logical comparative and statistical. Results the article is devoted to the problems of declining credit activity of commercial banks under the conditions of economic activity revival as well as to assessing the impact of the new reorganization mechanism on this process. It is shown that in the recent years the nonfinancial sector faces the trend of optimizing the corporate debts and the liquidity deficit which reduced the demand for loans and as a consequence decreased the banksrsquo credit activity. To analyze the dynamics of deficitsurplus of liquidity in the corporate sector a new classification of liquidity deficitsurplus levels was introduced. Based on the proposed classification the risk factors were identified that influenced the dynamics of indebtedness in the corporate sector. The article also analyses the modern monetary mechanism of money supply in the economy and its transformation. It was determined that the main limitation of credit issuance by commercial banks is their capital not the reserve multiplier. The new mechanism of credit institutionsrsquo financial recovery and its impact on the banksrsquo credit activity was estimated. The conditions of liquidity deficiency reduction in the Russian companies were analyzed in the medium term. Scientific novelty for the first time on the basis of system analysis methods the growth factors of the corporate debt load were identified the peculiarities of low

  7. Mismatch Receptive Fields in Mouse Visual Cortex.

    Science.gov (United States)

    Zmarz, Pawel; Keller, Georg B

    2016-11-23

    In primary visual cortex, a subset of neurons responds when a particular stimulus is encountered in a certain location in visual space. This activity can be modeled using a visual receptive field. In addition to visually driven activity, there are neurons in visual cortex that integrate visual and motor-related input to signal a mismatch between actual and predicted visual flow. Here we show that these mismatch neurons have receptive fields and signal a local mismatch between actual and predicted visual flow in restricted regions of visual space. These mismatch receptive fields are aligned to the retinotopic map of visual cortex and are similar in size to visual receptive fields. Thus, neurons with mismatch receptive fields signal local deviations of actual visual flow from visual flow predicted based on self-motion and could therefore underlie the detection of objects moving relative to the visual flow caused by self-motion. VIDEO ABSTRACT.

  8. The Age of Human Cerebral Cortex Neurons

    Energy Technology Data Exchange (ETDEWEB)

    Bhardwaj, R D; Curtis, M A; Spalding, K L; Buchholz, B A; Fink, D; Bjork-Eriksson, T; Nordborg, C; Gage, F H; Druid, H; Eriksson, P S; Frisen, J

    2006-04-06

    The traditional static view of the adult mammalian brain has been challenged by the realization of continuous generation of neurons from stem cells. Based mainly on studies in experimental animals, adult neurogenesis may contribute to recovery after brain insults and decreased neurogenesis has been implicated in the pathogenesis of neurological and psychiatric diseases in man. The extent of neurogenesis in the adult human brain has, however, been difficult to establish. We have taken advantage of the integration of {sup 14}C, generated by nuclear bomb tests during the Cold War, in DNA to establish the age of neurons in the major areas of the human cerebral cortex. Together with the analysis of the cortex from patients who received BrdU, which integrates in the DNA of dividing cells, our results demonstrate that whereas non-neuronal cells turn over, neurons in the human cerebral cortex are not generated postnatally at detectable levels, but are as old as the individual.

  9. Ultrastructural features of dopamine axon terminals in the anteromedial and the suprarhinal cortex of adult rat.

    Science.gov (United States)

    Séguéla, P; Watkins, K C; Descarries, L

    1988-02-23

    The ultrastructural features and synaptic relationships of dopamine (DA) axon terminals were examined in the prefrontal cortex of adult rat after immunocytochemical staining with a highly specific polyclonal antiserum directed against DA-glutaraldehyde-lysyl-protein conjugate (donated by M. Geffard). Single and serial ultrathin sections were obtained from the deep layers of the anteromedial and the suprarhinal DA fields. The DA axon terminals from both regions averaged 0.7 micron in diameter, contained a mixed population of small, round and clear synaptic vesicles associated with a few larger dense-cored or fully immunostained vesicles, and frequently exhibited synaptic contacts which were exclusively made on dendritic shafts and spines. These synapses were mostly of the symmetrical type (80%) and were more often seen on dendritic shafts than spines, particularly in the suprarhinal (89%) compared with the anteromedial cortex (62%). As estimated either by stereological extrapolation from single sections or by direct observation in serial sections, the synaptic incidence of these DA varicosities was significantly greater in the anteromedial than suprarhinal DA field. In the longest series of thin sections, a junctional complex could be observed on 93% of the DA varicosities from the anteromedial cortex but only on 56% in the suprarhinal cortex. Such an inter-regional disparity in the relational characteristics of the DA input will need to be taken into account in elucidating the role and properties of this monoamine in cerebral cortex.

  10. [Visco-hydraulic irrigation of the lens cortex. A safe ECCE method].

    Science.gov (United States)

    Friedburg, D

    1994-12-01

    The safe and effective Hydrojet nucleus expression (Klin Monatsbl Augenheilkd 1993; 202:288-291) should be completed by a safe non traumatic and easy to perform method of cortex removal. OPERATION TECHNIQUE: 8-mm tunnel incision, spiral capsulorhexis, hydrodissection and viscodissection of the nucleus, hydrojet nucleus expression. The lens cortex can be separated from the lens capsule by injection of hydroxypropylmethylcellulose (Metho), the viscoelastic substance acts as a wedge to separate the cortex from the capsule step by step. Finally the cortex is expressed by the injection of Metho. The capsule remains so clean, that often polishing is not necessary. PMMA lenses with an over all diameter of 10 or 11-mm and 7-mm optics were implanted. In 100 consecutive cases complications which occurred intraoperatively or within the following 2 days were listed. The following complications occurred: Hyphaema (2x, the blood disappeared spontaneously within 4-5 days), small cortex flake in the anterior chamber (2x), rhexis rim not intact (1x, nevertheless exact lens centration in the bag). No lesion of the capsule/zonule diaphragm, no fibrin reaction, no corneal edema. The method described is a safe method for ECCE. Capsulorhexis and tunnel incision are required. The method does not need any high technology equipment.

  11. The Anterior Cingulate Cortex and Pain Processing

    Directory of Open Access Journals (Sweden)

    Perry Neil Fuchs

    2014-05-01

    Full Text Available The neural network that contributes to the suffering which accompanies persistent pain states involves a number of brain regions. Of primary interest is the contribution of the cingulate cortex in processing the affective component of pain. The purpose of this review is to summarize recent data obtained using novel behavioral paradigms in animals based on measuring escape and/or avoidance of a noxious stimulus. These paradigms have successfully been used to study the nature of the neuroanatomical and neurochemical contributions of the anterior cingulate cortex to higher order pain processing in rodents.

  12. Coding of movements in the motor cortex.

    Science.gov (United States)

    Georgopoulos, Apostolos P; Carpenter, Adam F

    2015-08-01

    The issue of coding of movement in the motor cortex has recently acquired special significance due to its fundamental importance in neuroprosthetic applications. The challenge of controlling a prosthetic arm by processed motor cortical activity has opened a new era of research in applied medicine but has also provided an 'acid test' for hypotheses regarding coding of movement in the motor cortex. The successful decoding of movement information from the activity of motor cortical cells using their directional tuning and population coding has propelled successful neuroprosthetic applications and, at the same time, asserted the utility of those early discoveries, dating back to the early 1980s.

  13. Postictal inhibition of the somatosensory cortex

    DEFF Research Database (Denmark)

    Beniczky, Sándor; Jovanovic, Marina; Atkins, Mary Doreen

    2011-01-01

    Transient suppression of the motor cortex and of the speech areas cause well-described postictal phenomena following seizures involving the respective cortical areas. Pain is a rare symptom in epileptic seizures. We present a patient with painful tonic seizures in the left leg. The amplitude...... of the cortical component of the somatosensory evoked potential following stimulation of the left tibial nerve was reduced immediately after the seizure. Our findings suggest that the excitability of the sensory cortex is transiently reduced following a seizure involving the somatosensory area....

  14. Technological Similarity, Post-acquisition R&D Reorganization, and Innovation Performance in Horizontal Acquisition

    DEFF Research Database (Denmark)

    Colombo, Massimo G.; Rabbiosi, Larissa

    2014-01-01

    &D personnel. We rely on PLS techniques to test our theoretical model using detailed information on 31 horizontal acquisitions in high- and medium-tech industries. Our results indicate that in horizontal acquisitions, technological similarity negatively affects post-acquisition innovation performance......This paper aims to disentangle the mechanisms through which technological similarity between acquiring and acquired firms influences innovation in horizontal acquisitions. We develop a theoretical model that links technological similarity to: (i) two key aspects of post-acquisition reorganization...... of acquired R&D operations – the rationalization of the R&D operations and the replacement of the R&D top manager, and (ii) two intermediate effects that are closely associated with the post-acquisition innovation performance of the combined firm – improvements in R&D productivity and disruptions in R...

  15. Alteration and reorganization of functional networks: a new perspective in brain injury study

    Directory of Open Access Journals (Sweden)

    Nazareth P. Castellanos

    2011-09-01

    Full Text Available Plasticity is the mechanism underlying brain’s potential capability to compensate injury. Recently several studies have shown that functional connections among brain areas are severely altered by brain injury and plasticity leading to a reorganization of the networks. This new approach studies the impact of brain injury by means of alteration of functional interactions. The concept of functional connectivity refers to the statistical interdependencies between physiological time series simultaneously recorded in various brain areas and it could be an essential tool for brain function studies, being its deviation from healthy reference an indicator for damage. In this article, we review studies investigating functional connectivity changes after brain injury and subsequent recovery, providing an accessible introduction to common mathematical methods to infer functional connectivity, exploring their capabilities, future perspectives and clinical uses in brain injury studies.

  16. Reorganization of water utilities - regionalization, an opportunity to increase their efficiency A comparative literature - Albania Case

    Directory of Open Access Journals (Sweden)

    Julian Naqellari

    2017-03-01

    Full Text Available The purpose of this research is the study and analysis of factors affecting the need for reorganization of entities engaged in water supply services. From this perspective, the research seeks to identify international practices made in this regard and how they can be adapted to water utilities in Albania. The objective of this paper is to show that regionalization of water utilities is a successful development direction not only of studied literature but also practice in Albania. The study is based on sources of information taken from primary and secondary sources. The selected method for collecting and processing information from primary sources is the empirical method through direct surveys and questionnaires, whereas from secondary sources is descriptive and analytical method. As secondary sources, we are consulted and referred to academic resources, such as articles, books, studies and reports carried out and published by national organizations, local and foreign companies in this field.

  17. Reorganization of a hospital catering system increases food intake in patients with inadequate intake

    DEFF Research Database (Denmark)

    Freil, M.; Nielsen, M. A.; Biltz, C.

    2006-01-01

    the energy and protein intake of the patients. Design: Observational study comparing the food intake before and twice after the implementation of the new system, the first time by specially trained staff and the second time by ordinary staff members, following training. The amount of food served, eaten...... and wasted was measured, and energy and protein intake calculated. Results: The quartile of patients with the lowest energy intake consumed on average 128 kJ per patient [(95% confidence interval (CI) 79-178 kJ] with the old system; with the new system they consumed 560 kJ per patient (95% CI 489-631 k......: Reorganization of a hospital catering system can increase energy and protein intake and reduce waste substantially. Keywords: hospital food; nutritional risk; undernutrition...

  18. Reorganization of a hospital catering system increases food intake in patients with inadequate intake

    DEFF Research Database (Denmark)

    Freil, M; Nielsen, MA; Blitz, B

    2006-01-01

    , increases the energy and protein intake of the patients. Design: Observational study comparing the food intake before and twice after the implementation of the new system, the first time by specially trained staff and the second time by ordinary staff members, following training. The amount of food served......, eaten and wasted was measured, and energy and protein intake calculated. Results: The quartile of patients with the lowest energy intake consumed on average 128 kJ per patient [(95% confidence interval (CI) 79-178 kJ] with the old system; with the new system they consumed 560 kJ per patient (95% CI 489....... Conclusions: Reorganization of a hospital catering system can increase energy and protein intake and reduce waste substantially....

  19. Photovoltaic industry, towards a reorganization; Photovoltaique, vers une concentration du marche

    Energy Technology Data Exchange (ETDEWEB)

    Houot, G.

    2011-09-15

    During the first semester 2011 the sales of photovoltaic equipment have dropped unexpectedly, certainly due to the harsh winter in Europe and the reduction of the policy of financial incentives in some countries. This drop in demand has triggered such a drop in prices that some manufacturers face financial difficulties, for instance the American Evergreen Solar was declared bankrupt in mid august 2011. Today the production of solar panels exceeds the demand. The third term of 2011 shows an improvement but the sector will not escape a reorganization: there are too many manufacturers, some will disappear, other will merge, the biggest will stay. Some economists see the future market divided into 2 sectors: one sector dedicated to the mass production of classical solar panels at very low cost, this sector will be occupied mainly by Chinese companies and another sector demanding a more specialized know-how will be driven by American, Japanese and European companies. (A.C.)

  20. Microcirculation and structural reorganization of the bladder mucosa in chronic cystitis under conditions of ozone therapy.

    Science.gov (United States)

    Neimark, A I; Nepomnyashchikh, L M; Lushnikova, E L; Bakarev, M A; Abdullaev, N A; Sizov, K A

    2014-01-01

    Structural reorganization of the bladder mucosa in chronic cystitis and its correction by ozone therapy were studied. A relationship between the epithelial layer restructuring of different kinds (dystrophy, metaplasia, and degeneration), level of cell proliferation, and ultrastructural organization of urotheliocytes was detected. This complex of structural reactions was combined with dysregulation of tissue bloodflow in the bladder mucosa, shown by laser Doppler flowmetry. Positive structural changes were most marked in intravesical and less so in parenteral ozone therapy added to the therapeutic complex and manifested in reduction of inflammation and alteration in parallel with more intense reparative reactions. A special feature of parenteral ozone therapy was a significant improvement of microcirculation in the bladder mucosa.

  1. Optimizing resource allocation and patient flow: process analysis and reorganization in three chemotherapy outpatient clinics.

    Science.gov (United States)

    Holmes, Morgan; Bodie, Kelly; Porter, Geoffrey; Sullivan, Victoria; Tarasuk, Joy; Trembley, Jodie; Trudeau, Maureen

    2010-01-01

    Optimizing human and physical resources is a major concern for cancer care decision-makers and practitioners. This issue is particularly acute in the context of ambulatory out patient chemotherapy clinics, especially when - as is the case almost everywhere in the industrialized world - the number of people requiring systemic therapy is increasing while budgets, staffing and physical space remain static. Recent initiatives at three hospital-based chemotherapy units - in Halifax, Toronto and Kingston - shed light on the value of process analysis and reorganization for using existing human and physical resources to their full potential, improving patient flow and enhancing patient satisfaction. The steps taken in these settings are broadly applicable to other healthcare settings and would likely result in similar benefits in those environments.

  2. Constraint-induced movement therapy promotes brain functional reorganization in stroke patients with hemiplegia

    Institute of Scientific and Technical Information of China (English)

    Wenqing Wang; Aihui Wang; Limin Yu; Xuesong Han; Guiyun Jiang; Changshui Weng; Hongwei Zhang; Zhiqiang Zhou

    2012-01-01

    Stroke patients with hemiplegia exhibit flexor spasms in the upper limb and extensor spasms in the lower limb, and their movement patterns vary greatly. Constraint-induced movement therapy is an upper limb rehabilitation technique used in stroke patients with hemiplegia; however, studies of lower extremity rehabilitation are scarce. In this study, stroke patients with lower limb hemiplegia underwent conventional Bobath therapy for 4 weeks as baseline treatment, followed by constraint-induced movement therapy for an additional 4 weeks. The 10-m maximum walking speed and Berg balance scale scores significantly improved following treatment, and lower extremity motor function also improved. The results of functional MRI showed that constraint-induced movement therapy alleviates the reduction in cerebral functional activation in patients, which indicates activation of functional brain regions and a significant increase in cerebral blood perfusion. These results demonstrate that constraint-induced movement therapy promotes brain functional reorganization in stroke patients with lower limb hemiplegia.

  3. ATM Dependent Silencing Links Nucleolar Chromatin Reorganization to DNA Damage Recognition.

    Science.gov (United States)

    Harding, Shane M; Boiarsky, Jonathan A; Greenberg, Roger A

    2015-10-13

    Resolution of DNA double-strand breaks (DSBs) is essential for the suppression of genome instability. DSB repair in transcriptionally active genomic regions represents a unique challenge that is associated with ataxia telangiectasia mutated (ATM) kinase-mediated transcriptional silencing. Despite emerging insights into the underlying mechanisms, how DSB silencing connects to DNA repair remains undefined. We observe that silencing within the rDNA depends on persistent DSBs. Non-homologous end-joining was the predominant mode of DSB repair allowing transcription to resume. ATM-dependent rDNA silencing in the presence of persistent DSBs led to the large-scale reorganization of nucleolar architecture, with movement of damaged chromatin to nucleolar cap regions. These findings identify ATM-dependent temporal and spatial control of DNA repair and provide insights into how communication between DSB signaling and ongoing transcription promotes genome integrity.

  4. ATM Dependent Silencing Links Nucleolar Chromatin Reorganization to DNA Damage Recognition

    Directory of Open Access Journals (Sweden)

    Shane M. Harding

    2015-10-01

    Full Text Available Resolution of DNA double-strand breaks (DSBs is essential for the suppression of genome instability. DSB repair in transcriptionally active genomic regions represents a unique challenge that is associated with ataxia telangiectasia mutated (ATM kinase-mediated transcriptional silencing. Despite emerging insights into the underlying mechanisms, how DSB silencing connects to DNA repair remains undefined. We observe that silencing within the rDNA depends on persistent DSBs. Non-homologous end-joining was the predominant mode of DSB repair allowing transcription to resume. ATM-dependent rDNA silencing in the presence of persistent DSBs led to the large-scale reorganization of nucleolar architecture, with movement of damaged chromatin to nucleolar cap regions. These findings identify ATM-dependent temporal and spatial control of DNA repair and provide insights into how communication between DSB signaling and ongoing transcription promotes genome integrity.

  5. Structural reorganization of the fungal endoplasmic reticulum upon induction of mycotoxin biosynthesis

    Science.gov (United States)

    Boenisch, Marike Johanne; Broz, Karen Lisa; Purvine, Samuel Owen; Chrisler, William Byron; Nicora, Carrie Diana; Connolly, Lanelle Reine; Freitag, Michael; Baker, Scott Edward; Kistler, Harold Corby

    2017-01-01

    Compartmentalization of metabolic pathways to particular organelles is a hallmark of eukaryotic cells. Knowledge of the development of organelles and attendant pathways under different metabolic states has been advanced by live cell imaging and organelle specific analysis. Nevertheless, relatively few studies have addressed the cellular localization of pathways for synthesis of fungal secondary metabolites, despite their importance as bioactive compounds with significance to medicine and agriculture. When triggered to produce sesquiterpene (trichothecene) mycotoxins, the endoplasmic reticulum (ER) of the phytopathogenic fungus Fusarium graminearum is reorganized both in vitro and in planta. Trichothecene biosynthetic enzymes accumulate in organized smooth ER with pronounced expansion at perinuclear- and peripheral positions. Fluorescence tagged trichothecene biosynthetic proteins co-localize with the modified ER as confirmed by co-fluorescence and co-purification with known ER proteins. We hypothesize that changes to the fungal ER represent a conserved process in specialized eukaryotic cells such as in mammalian hepatocytes and B-cells. PMID:28287158

  6. Constraint-induced movement therapy promotes brain functional reorganization in stroke patients with hemiplegia.

    Science.gov (United States)

    Wang, Wenqing; Wang, Aihui; Yu, Limin; Han, Xuesong; Jiang, Guiyun; Weng, Changshui; Zhang, Hongwei; Zhou, Zhiqiang

    2012-11-15

    Stroke patients with hemiplegia exhibit flexor spasms in the upper limb and extensor spasms in the lower limb, and their movement patterns vary greatly. Constraint-induced movement therapy is an upper limb rehabilitation technique used in stroke patients with hemiplegia; however, studies of lower extremity rehabilitation are scarce. In this study, stroke patients with lower limb hemiplegia underwent conventional Bobath therapy for 4 weeks as baseline treatment, followed by constraint-induced movement therapy for an additional 4 weeks. The 10-m maximum walking speed and Berg balance scale scores significantly improved following treatment, and lower extremity motor function also improved. The results of functional MRI showed that constraint-induced movement therapy alleviates the reduction in cerebral functional activation in patients, which indicates activation of functional brain regions and a significant increase in cerebral blood perfusion. These results demonstrate that constraint-induced movement therapy promotes brain functional reorganization in stroke patients with lower limb hemiplegia.

  7. Necessity of Re-Organization of Turkish Agricultural Higher Education System

    Directory of Open Access Journals (Sweden)

    P. Ulger

    2006-01-01

    Full Text Available Education in Agricultural Faculties has been changing from beginning to these days in Turkey. However, education in agriculture always contains all area of agriculture and students are awarded the same diploma which is “Agricultural Engineer” after four years. By means of science and technology has been developing, agricultural applications also have been changing recently. This resulted in increasing of requirements from agricultural engineer in respect of both wide and deep knowledge about agriculture. In this study it was aimed that clarification of history of agricultural higher education from the beginning till now in Turkey and agricultural higher education systems in some developed countries. Necessity of re-organization of Turkish agricultural higher education system was also discussed and some recommendations about this theme were given.

  8. Cross-Modal Re-Organization in Clinical Populations with Hearing Loss

    Directory of Open Access Journals (Sweden)

    Anu Sharma

    2016-01-01

    Full Text Available We review evidence for cross-modal cortical re-organization in clinical populations with hearing loss. Cross-modal plasticity refers to the ability for an intact sensory modality (e.g., vision or somatosensation to recruit cortical brain regions from a deprived sensory modality (e.g., audition to carry out sensory processing. We describe evidence for cross-modal changes in hearing loss across the age-spectrum and across different degrees of hearing impairment, including children with profound, bilateral deafness with cochlear implants, single-sided deafness before and after cochlear implantation, and adults with early-stage, mild-moderate, age-related hearing loss. Understanding cross-modal plasticity in the context of auditory deprivation, and the potential for reversal of these changes following intervention, may be vital in directing intervention and rehabilitation options for clinical populations with hearing loss.

  9. Rapid reorganization in ocean biogeochemistry off Peru towards the end of the Little Ice Age

    Directory of Open Access Journals (Sweden)

    D. Gutiérrez

    2008-09-01

    Full Text Available Climate and ocean ecosystem variability has been well recognized during the twentieth century but it is unclear if modern ocean biogeochemistry is susceptible to the large, abrupt shifts that characterized the Late Quaternary. Time series from marine sediments off Peru show an abrupt centennial-scale biogeochemical regime shift in the early nineteenth century, of much greater magnitude and duration than present day multi-decadal variability. A rapid expansion of the subsurface nutrient-rich, oxygen-depleted waters resulted in higher biological productivity, including pelagic fish. The shift was likely driven by a northward migration of the Intertropical Convergence Zone and the South Pacific Subtropical High to their present day locations, coupled with a strengthening of Walker circulation, towards the end of the Little Ice Age. These findings reveal the potential for large reorganizations in tropical Pacific climate with immediate effects on ocean biogeochemical cycling and ecosystem structure.

  10. Constraint-induced movement therapy promotes brain functional reorganization in stroke patients with hemiplegia

    Science.gov (United States)

    Wang, Wenqing; Wang, Aihui; Yu, Limin; Han, Xuesong; Jiang, Guiyun; Weng, Changshui; Zhang, Hongwei; Zhou, Zhiqiang

    2012-01-01

    Stroke patients with hemiplegia exhibit flexor spasms in the upper limb and extensor spasms in the lower limb, and their movement patterns vary greatly. Constraint-induced movement therapy is an upper limb rehabilitation technique used in stroke patients with hemiplegia; however, studies of lower extremity rehabilitation are scarce. In this study, stroke patients with lower limb hemiplegia underwent conventional Bobath therapy for 4 weeks as baseline treatment, followed by constraint-induced movement therapy for an additional 4 weeks. The 10-m maximum walking speed and Berg balance scale scores significantly improved following treatment, and lower extremity motor function also improved. The results of functional MRI showed that constraint-induced movement therapy alleviates the reduction in cerebral functional activation in patients, which indicates activation of functional brain regions and a significant increase in cerebral blood perfusion. These results demonstrate that constraint-induced movement therapy promotes brain functional reorganization in stroke patients with lower limb hemiplegia. PMID:25337108

  11. Cocaine exposure reorganizes cell type- and input-specific connectivity in the nucleus accumbens.

    Science.gov (United States)

    MacAskill, Andrew F; Cassel, John M; Carter, Adam G

    2014-09-01

    Repeated exposure to cocaine alters the structural and functional properties of medium spiny neurons (MSNs) in the nucleus accumbens (NAc). These changes suggest a rewiring of the NAc circuit, with an enhancement of excitatory synaptic connections onto MSNs. However, it is unknown how drug exposure alters the balance of long-range afferents onto different cell types in the NAc. Here we used whole-cell recordings, two-photon microscopy, optogenetics and pharmacogenetics to show how repeated cocaine exposure alters connectivity in the mouse NAc medial shell. Cocaine selectively enhanced amygdala innervation of MSNs expressing D1 dopamine receptors (D1-MSNs) relative to D2-MSNs. We also found that amygdala activity was required for cocaine-induced changes to behavior and connectivity. Finally, we established how heightened amygdala innervation can explain the structural and functional changes evoked by cocaine. Our findings reveal how exposure to drugs of abuse fundamentally reorganizes cell type- and input-specific connectivity in the NAc.

  12. [A major game in the re-organization of the Professional Nursing School].

    Science.gov (United States)

    de Amorin, Wellington Mendonça; Barreira, Ieda de Alencar

    2007-01-01

    This is a historical-social description study supported on the thought of Pierre Bourdieu based on documental analysis. It describes the sanitarists and psychiatrists' actions from the reformulation of Education and Public Health Ministry into Education and Health Ministry in the beginning of New State and analyse the fight's strategies of the main agents to take advantage on their proposals of Professional Nursing School's reorganization. The fight's strategies that psychiatrists, sanitarists and certificated nurses had used to stake their projects, characterized a difficult battle inserted in a hard major game. The analyse of the ten course's months of the main document shows the conflict between those agents to impose a new rule to the school.

  13. Tropical Forest Reorganization after Cyclone and Fire Disturbance in Samoa: Remnant Trees as Biological Legacies

    Directory of Open Access Journals (Sweden)

    Åsa Fritioff

    2002-01-01

    Full Text Available In disturbed rain forests, large, living remnant trees may be of significant importance for postdisturbance reorganization either directly, by producing large quantities of seeds, or indirectly, by attracting vertebrate seed dispersers. In addition, remnant trees may also be important in providing a favorable microhabitat for seedlings of late-successional species. This study focused on the role of large remnant trees (> 40 cm dbh in patterns of regeneration after cyclone and fire damage in the Tafua and Falealupo Rain Forest Preserves, Savaií, Samoa. At Tafua, 10 large trees at each of two sites (one site burned in 1990 were investigated with regard to numbers of species and densities of plants from three different size classes at different distances from remnant trees. At the burned site, both species richness and the densities of plants < 1cm dbh were significantly higher inside the canopies of remnant trees than outside of them. At the unburned site, no or only marginally significant differences were observed. At Falealupo, two burned sites (burned in 1993 and 1998 were investigated using seed traps. At both sites, the seed rain from vertebrate dispersers was disproportionally higher under the canopies of remnant trees than in outside areas. No differences in soil characteristics were found when comparing samples taken from inside and outside canopies. Our results are congruent with the prediction that large remnant trees surviving in severely disturbed rain-forest areas represent biological legacies and serve as nuclei for reorganization. Based on this study and our previous work, we suggest that three factors represent essential components of the spatial resilience of tropical forest ecosystems and should be targeted for active management in tropical forests exposed to large-scale disturbances, particularly fire: remnant trees, refugia, and vertebrate dispersers.

  14. Reorganization of Sleep by Temperature in Drosophila Requires Light, the Homeostat, and the Circadian Clock.

    Science.gov (United States)

    Parisky, Katherine M; Agosto Rivera, José L; Donelson, Nathan C; Kotecha, Sejal; Griffith, Leslie C

    2016-04-04

    Increasing ambient temperature reorganizes the Drosophila sleep pattern in a way similar to the human response to heat, increasing daytime sleep while decreasing nighttime sleep. Mutation of core circadian genes blocks the immediate increase in daytime sleep, but not the heat-stimulated decrease in nighttime sleep, when animals are in a light:dark cycle. The ability of per(01) flies to increase daytime sleep in light:dark can be rescued by expression of PER in either LNv or DN1p clock cells and does not require rescue of locomotor rhythms. Prolonged heat exposure engages the homeostat to maintain daytime sleep in the face of nighttime sleep loss. In constant darkness, all genotypes show an immediate decrease in sleep in response to temperature shift during the subjective day, implying that the absence of light input uncovers a clock-independent pro-arousal effect of increased temperature. Interestingly, the effects of temperature on nighttime sleep are blunted in constant darkness and in cry(OUT) mutants in light:dark, suggesting that they are dependent on the presence of light the previous day. In contrast, flies of all genotypes kept in constant light sleep more at all times of day in response to high temperature, indicating that the presence of light can invert the normal nighttime response to increased temperature. The effect of temperature on sleep thus reflects coordinated regulation by light, the homeostat, and components of the clock, allowing animals to reorganize sleep patterns in response to high temperature with rough preservation of the total amount of sleep.

  15. Molecular simulations of outersphere reorganization energies for intramolecular electron and hole transfer in polar solvents

    Science.gov (United States)

    Leontyev, I. V.; Tovmash, A. V.; Vener, M. V.; Rostov, I. V.; Basilevsky, M. V.

    2005-12-01

    Outersphere reorganization energies ( λ) for intramolecular electron transfer (ET) and hole transfer are studied in anion- and cation-radical forms of complex organic substrates (biphenylyl-spacer-naphtyl) in polar solvents simulated by means of the nonpolarizable models of water and 1,2-dichloroethane. The earlier elaborated molecular/continuum approach (the MD/FRCM, J. Chem. Phys., 119 (2003) 8024) is used; this method provides a physically relevant background for separating inertial and inertialess polarization responses within a nonpolarizable MD simulation (the SPC water model). Quantum-chemical calculations of solute charge distributions were performed with semiempirical (AM1) and second ab initio (HF/6-31G(d,p)) approximations. Ab initio charges give lower λ-values and are preferable, probably, because of including the effect of the SCRF polarization of the diabatic ET states. Standard Lennard-Jones and charge parameters implemented in MD runs were not specially fitted for reproducing ET effects. The difference in values for a cation and an anion originating from the same parent structure was specially investigated. As shown earlier, this effect, nonlinear in its nature, proved to be extremely large when a model dipolar two-site system was studied. For the present ET structures representing real chemical substrates it has reduced to a plausible value of 6-8 kcal/mol. The study of the temperature dependence of λ comprises a first MD simulation of this problem and its slope was found to be in accord with an experimental observation for an anionic species. Calculations of absolute λ-values for the hole transfer in 1,2-dichloroethane are the first MD simulations of reorganization energies in experimentally studied reactions. Computed values of λ-s are higher than the experimental data. The effect of this magnitude could be eliminated by proper tuning the solvent parameters.

  16. Exploring non-stationarity patterns in schizophrenia: neural reorganization abnormalities in the alpha band

    Science.gov (United States)

    Núñez, Pablo; Poza, Jesús; Bachiller, Alejandro; Gomez-Pilar, Javier; Lubeiro, Alba; Molina, Vicente; Hornero, Roberto

    2017-08-01

    Objective. The aim of this paper was to characterize brain non-stationarity during an auditory oddball task in schizophrenia (SCH). The level of non-stationarity was measured in the baseline and response windows of relevant tones in SCH patients and healthy controls. Approach. Event-related potentials were recorded from 28 SCH patients and 51 controls. Non-stationarity was estimated in the conventional electroencephalography frequency bands by means of Kullback-Leibler divergence (KLD). Relative power (RP) was also computed to assess a possible complementarity with KLD. Main results. Results showed a widespread statistically significant increase in the level of non-stationarity from baseline to response in all frequency bands for both groups. Statistically significant differences in non-stationarity were found between SCH patients and controls in beta-2 and in the alpha band. SCH patients showed more non-stationarity in the left parieto-occipital region during the baseline window in the beta-2 band. A leave-one-out cross validation classification study with feature selection based on binary stepwise logistic regression to discriminate between SCH patients and controls provided a positive predictive value of 72.73% and negative predictive value of 78.95%. Significance. KLD can characterize transient neural reorganization during an attentional task in response to novelty and relevance. Our findings suggest anomalous reorganization of neural dynamics in SCH during an oddball task. The abnormal frequency-dependent modulation found in SCH patients during relevant tones is in agreement with the hypothesis of aberrant salience detection in SCH. The increase in non-stationarity in the alpha band during the active task supports the notion that this band is involved in top-down processing. The baseline differences in the beta-2 band suggest that hyperactivation of the default mode network during attention tasks may be related to SCH symptoms. Furthermore, the classification

  17. Grasp movement decoding from premotor and parietal cortex.

    Science.gov (United States)

    Townsend, Benjamin R; Subasi, Erk; Scherberger, Hansjörg

    2011-10-05

    Despite recent advances in harnessing cortical motor-related activity to control computer cursors and robotic devices, the ability to decode and execute different grasping patterns remains a major obstacle. Here we demonstrate a simple Bayesian decoder for real-time classification of grip type and wrist orientation in macaque monkeys that uses higher-order planning signals from anterior intraparietal cortex (AIP) and ventral premotor cortex (area F5). Real-time decoding was based on multiunit signals, which had similar tuning properties to cells in previous single-unit recording studies. Maximum decoding accuracy for two grasp types (power and precision grip) and five wrist orientations was 63% (chance level, 10%). Analysis of decoder performance showed that grip type decoding was highly accurate (90.6%), with most errors occurring during orientation classification. In a subsequent off-line analysis, we found small but significant performance improvements (mean, 6.25 percentage points) when using an optimized spike-sorting method (superparamagnetic clustering). Furthermore, we observed significant differences in the contributions of F5 and AIP for grasp decoding, with F5 being better suited for classification of the grip type and AIP contributing more toward decoding of object orientation. However, optimum decoding performance was maximal when using neural activity simultaneously from both areas. Overall, these results highlight quantitative differences in the functional representation of grasp movements in AIP and F5 and represent a first step toward using these signals for developing functional neural interfaces for hand grasping.

  18. 78 FR 44523 - Reorganization of Foreign-Trade Zone 122 Under Alternative Site Framework; Corpus Christi, Texas

    Science.gov (United States)

    2013-07-24

    ...; Corpus Christi, Texas Pursuant to its authority under the Foreign-Trade Zones Act of June 18, 1934, as... establishment or reorganization of zones; Whereas, the Port of Corpus Christi Authority, grantee of Foreign..., Kleberg and Bee Counties, Texas, within and adjacent to the Corpus Christi Customs and Border...

  19. 75 FR 72801 - Reorganization of Foreign-Trade Zone 152 Under Alternative Site Framework Burns Harbor, IN

    Science.gov (United States)

    2010-11-26

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE Foreign-Trade Zones Board Reorganization of Foreign-Trade Zone 152 Under Alternative Site Framework Burns Harbor, IN Pursuant to its authority under the Foreign-Trade Zones Act of June 18, 1934, as amended (19...

  20. 76 FR 1133 - Foreign-Trade Zone 152-Burns Harbor, IN, Application for Reorganization (Expansion of Service...

    Science.gov (United States)

    2011-01-07

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE Foreign-Trade Zones Board Foreign-Trade Zone 152--Burns Harbor, IN, Application for Reorganization (Expansion of Service Area) Under the Alternative Site Framework An application has been submitted to...

  1. 77 FR 59891 - Reorganization of Foreign-Trade Zone 107 Under Alternative Site Framework, Polk County, IA

    Science.gov (United States)

    2012-10-01

    ... Board adopted the alternative site framework (ASF) (74 FR 1170, 01/12/09; correction 74 FR 3987, 01/22/09; 75 FR 71069-71070, 11/22/10) as an option for the establishment or reorganization of zones...; Whereas, notice inviting public comment was given in the Federal Register (77 FR 8805-8806, 2/15/2012)...

  2. 78 FR 36165 - Reorganization/Expansion of Foreign-Trade Zone 104; (Expansion of Service Area and Expansion of...

    Science.gov (United States)

    2013-06-17

    ... Federal Register (77 FR 43047, 07/23/12) and the application has been processed pursuant to the FTZ Act... Foreign-Trade Zones Board Reorganization/Expansion of Foreign-Trade Zone 104; (Expansion of Service Area and Expansion of Zone); Under Alternative Site Framework, Savannah, Georgia Pursuant to its...

  3. Motor Recovery and Cortical Reorganization After Mirror Therapy in Chronic Stroke Patients : A Phase II Randomized Controlled Trial

    NARCIS (Netherlands)

    Michielsen, Marian E.; Selles, Ruud W.; van der Geest, Jos N.; Eckhardt, Martine; Yavuzer, Gunes; Stam, Henk J.; Smits, Marion; Ribbers, Gerard M.; Bussmann, Johannes B. J.

    2011-01-01

    Objective. To evaluate for any clinical effects of home-based mirror therapy and subsequent cortical reorganization in patients with chronic stroke with moderate upper extremity paresis. Methods. A total of 40 chronic stroke patients (mean time post. onset, 3.9 years) were randomly assigned to the

  4. 76 FR 65171 - Foreign-Trade Zone 272-Counties of Lehigh and Northampton, PA; Application for Reorganization...

    Science.gov (United States)

    2011-10-20

    ... Zones (FTZ) Board (the Board) by the Lehigh Valley Economic Development Corporation, grantee of FTZ 272... Customs and Border Protection port of entry. The applicant is requesting authority to reorganize its... sites. The ASF allows for the possible exemption of one magnet site from the ``sunset'' time limits...

  5. Reorganization of the Cerebro-Cerebellar Network of Language Production in Patients with Congenital Left-Hemispheric Brain Lesions

    Science.gov (United States)

    Lidzba, K.; Wilke, M.; Staudt, M.; Krageloh-Mann, I.; Grodd, W.

    2008-01-01

    Patients with congenital lesions of the left cerebral hemisphere may reorganize language functions into the right hemisphere. In these patients, language production is represented homotopically to the left-hemispheric language areas. We studied cerebellar activation in five patients with congenital lesions of the left cerebral hemisphere to assess…

  6. 77 FR 41742 - Reorganization and Expansion of Foreign-Trade Zone 202 Under Alternative Site Framework Los...

    Science.gov (United States)

    2012-07-16

    ... Framework Los Angeles, CA Pursuant to its authority under the Foreign-Trade Zones Act of June 18, 1934, as... general-purpose zones; Whereas, the Board of Harbor Commissioners of the City of Los Angeles, grantee of... authority to reorganize and expand under the ASF with a service area of Orange County and portions of Los...

  7. 76 FR 50717 - Foreign-Trade Zone 74, Baltimore, MD; Application for Reorganization/Expansion Under Alternative...

    Science.gov (United States)

    2011-08-16

    ... (Site 9); Henry Bath (Site 12); Under Armour (Site 13); Pacorini Metals (Sites 17 & 25); Ruxton Services... Under Alternative Site Framework An application has been submitted to the Foreign-Trade Zones (FTZ... of FTZ 74, requesting authority to reorganize and expand the zone under the alternative site...

  8. Reorganization of the Cerebro-Cerebellar Network of Language Production in Patients with Congenital Left-Hemispheric Brain Lesions

    Science.gov (United States)

    Lidzba, K.; Wilke, M.; Staudt, M.; Krageloh-Mann, I.; Grodd, W.

    2008-01-01

    Patients with congenital lesions of the left cerebral hemisphere may reorganize language functions into the right hemisphere. In these patients, language production is represented homotopically to the left-hemispheric language areas. We studied cerebellar activation in five patients with congenital lesions of the left cerebral hemisphere to assess…

  9. 77 FR 43048 - Foreign-Trade Zone 8-Toledo, OH; Application for Reorganization and Expansion Under Alternative...

    Science.gov (United States)

    2012-07-23

    ... Foreign-Trade Zones Board Foreign-Trade Zone 8--Toledo, OH; Application for Reorganization and Expansion...) Board (the Board) by the Toledo-Lucas County Port Authority, grantee of FTZ 8, requesting authority to...: Site 1 (332 acres)--Port of Toledo Complex, Toledo; Site 2 (337 acres)--Toledo Express Airport, 11311...

  10. 78 FR 1197 - Reorganization/Expansion of Foreign-Trade Zone 8 Under Alternative Site Framework; Toledo, OH

    Science.gov (United States)

    2013-01-08

    ... Framework; Toledo, OH Pursuant to its authority under the Foreign-Trade Zones Act of June 18, 1934, as... establishment or reorganization of zones; Whereas, the Toledo-Lucas County Port Authority, grantee of Foreign..., Lucas and Defiance Counties, Ohio, in and adjacent to the Toledo- Sandusky Customs and Border...

  11. Insular cortex and neuropsychiatric disorders: a review of recent literature.

    Science.gov (United States)

    Nagai, M; Kishi, K; Kato, S

    2007-09-01

    The insular cortex is located in the centre of the cerebral hemisphere, having connections with the primary and secondary somatosensory areas, anterior cingulate cortex, amygdaloid body, prefrontal cortex, superior temporal gyrus, temporal pole, orbitofrontal cortex, frontal and parietal opercula, primary and association auditory cortices, visual association cortex, olfactory bulb, hippocampus, entorhinal cortex, and motor cortex. Accordingly, dense connections exist among insular cortex neurons. The insular cortex is involved in the processing of visceral sensory, visceral motor, vestibular, attention, pain, emotion, verbal, motor information, inputs related to music and eating, in addition to gustatory, olfactory, visual, auditory, and tactile data. In this article, the literature on the relationship between the insular cortex and neuropsychiatric disorders was summarized following a computer search of the Pub-Med database. Recent neuroimaging data, including voxel based morphometry, PET and fMRI, revealed that the insular cortex was involved in various neuropsychiatric diseases such as mood disorders, panic disorders, PTSD, obsessive-compulsive disorders, eating disorders, and schizophrenia. Investigations of functions and connections of the insular cortex suggest that sensory information including gustatory, olfactory, visual, auditory, and tactile inputs converge on the insular cortex, and that these multimodal sensory information may be integrated there.

  12. Presurgical language mapping in epilepsy: Using fMRI of reading to identify functional reorganization in a patient with long-standing temporal lobe epilepsy

    Directory of Open Access Journals (Sweden)

    Layla Gould

    2016-01-01

    Full Text Available We report a 55-year-old, right-handed patient with intractable left temporal lobe epilepsy, who previously had a partial left temporal lobectomy. The patient could talk during seizures, suggesting that he might have language dominance in the right hemisphere. Presurgical fMRI localization of language processing including reading of exception and regular words, pseudohomophones, and dual meaning words confirmed the clinical hypothesis of right language dominance, with only small amounts of activation near the planned surgical resection and, thus, minimal eloquent cortex to avoid during surgery. Postoperatively, the patient was rendered seizure-free without speech deficits.

  13. Maternal determinants and mRNAs in the cortex of ascidian oocytes, zygotes and embryos.

    Science.gov (United States)

    Sardet, Christian; Dru, Philippe; Prodon, François

    2005-01-01

    The peripheral region of ascidian oocytes and zygotes contains five determinants for morphogenesis and differentiation of the embryo. The determinant for the 24 primary muscle cells of the tadpole, macho1, is one of several cortical mRNAs localized in a gradient along the animal-vegetal axis in the oocyte. After fertilization these mRNAs, together with cortical endoplasmic reticulum (cER) and a subcortical mitochondria-rich domain (myoplasm), relocate in two major reorganization phases forming the posterior plasm (postplasm) of the zygote. At the 8-cell stage cortical mRNAs concentrate in a macroscopic cortical structure called the centrosome-attracting body (CAB), forming a characteristic posterior end mark (PEM) in the two posterior vegetal blastomeres. We propose to call the numerous mRNAs showing this particular cortical localization in the posterior region of the embryo postplasmic/PEM RNAs and suggest a nomemclature. We do not know how postplasmic/PEM RNAs reach their polarized distribution in the oocyte cortex but at least PEM1 and macho1 (and probably others) bind to the network of cER retained in isolated cortical fragments. We propose that after fertilization, these postplasmic/PEM mRNAs move in the zygote cortex together with the cER network (cER/mRNA domain) via microfilament- and microtubule-driven translocations. The cER/mRNA domain is localized posteriorly at the time of first cleavage and distributed equally between the first two blastomeres. After the third cleavage, the cER/mRNA domain and dense particles compact to form the CAB in posterior vegetal blastomeres of the 8-cell stage. We discuss the identity of postplasmic/PEM RNAs, how they localize, anchor, relocate and may be translated. We also examine their roles in unequal cleavage and as a source of posterior morphogenetic and differentiation factors.

  14. Microglia in the Cerebral Cortex in Autism

    Science.gov (United States)

    Tetreault, Nicole A.; Hakeem, Atiya Y.; Jiang, Sue; Williams, Brian A.; Allman, Elizabeth; Wold, Barbara J.; Allman, John M.

    2012-01-01

    We immunocytochemically identified microglia in fronto-insular (FI) and visual cortex (VC) in autopsy brains of well-phenotyped subjects with autism and matched controls, and stereologically quantified the microglial densities. Densities were determined blind to phenotype using an optical fractionator probe. In FI, individuals with autism had…

  15. Structure of Orbitofrontal Cortex Predicts Social Influence

    DEFF Research Database (Denmark)

    Campbell-Meiklejohn, Daniel; Kanai, Ryota; Bahrami, Bahador

    2012-01-01

    to guide choices and behaviour. These values can often be updated by the expressed preferences of other people as much as by independent experience. In this correspondence, we report a linear relationship between grey matter volume (GM) in a region of lateral orbitofrontal cortex (lOFCGM) and the tendency...

  16. Primary Auditory Cortex Regulates Threat Memory Specificity

    Science.gov (United States)

    Wigestrand, Mattis B.; Schiff, Hillary C.; Fyhn, Marianne; LeDoux, Joseph E.; Sears, Robert M.

    2017-01-01

    Distinguishing threatening from nonthreatening stimuli is essential for survival and stimulus generalization is a hallmark of anxiety disorders. While auditory threat learning produces long-lasting plasticity in primary auditory cortex (Au1), it is not clear whether such Au1 plasticity regulates memory specificity or generalization. We used…

  17. The Piriform Cortex and Human Focal Epilepsy

    Directory of Open Access Journals (Sweden)

    David eVaughan

    2014-12-01

    Full Text Available It is surprising that the piriform cortex, when compared to the hippocampus, has been given relatively little significance in human epilepsy. Like the hippocampus, it has a phylogenetically preserved three-layered cortex that is vulnerable to excitotoxic injury, has broad connections to both limbic and cortical areas, and is highly epileptogenic - being critical to the kindling process. The well-known phenomenon of early olfactory auras in temporal lobe epilepsy highlights its clinical relevance in humans. Perhaps because it is anatomically indistinct and difficult to approach surgically, as it clasps the middle cerebral artery, it has, until now, been understandably neglected. In this review we emphasize how its unique anatomical and functional properties, as primary olfactory cortex, predispose it to involvement in focal epilepsy. From recent convergent findings in human neuroimaging, clinical epileptology and experimental animal models, we make the case that the piriform cortex is likely to play a facilitating and amplifying role in human focal epileptogenesis, and may influence progression to epileptic intractability.

  18. The piriform cortex and human focal epilepsy.

    Science.gov (United States)

    Vaughan, David N; Jackson, Graeme D

    2014-01-01

    It is surprising that the piriform cortex, when compared to the hippocampus, has been given relatively little significance in human epilepsy. Like the hippocampus, it has a phylogenetically preserved three-layered cortex that is vulnerable to excitotoxic injury, has broad connections to both limbic and cortical areas, and is highly epileptogenic - being critical to the kindling process. The well-known phenomenon of early olfactory auras in temporal lobe epilepsy highlights its clinical relevance in human beings. Perhaps because it is anatomically indistinct and difficult to approach surgically, as it clasps the middle cerebral artery, it has, until now, been understandably neglected. In this review, we emphasize how its unique anatomical and functional properties, as primary olfactory cortex, predispose it to involvement in focal epilepsy. From recent convergent findings in human neuroimaging, clinical epileptology, and experimental animal models, we make the case that the piriform cortex is likely to play a facilitating and amplifying role in human focal epileptogenesis, and may influence progression to epileptic intractability.

  19. Contour extracting networks in early extrastriate cortex

    NARCIS (Netherlands)

    Dumoulin, Serge O.; Hess, Robert F.; May, Keith A.; Harvey, Ben M.; Rokers, Bas; Barendregt, Martijn

    2014-01-01

    Neurons in the visual cortex process a local region of visual space, but in order to adequately analyze natural images, neurons need to interact. The notion of an ''association field'' proposes that neurons interact to extract extended contours. Here, we identify the site and properties of contour

  20. Mapping tonotopy in human auditory cortex

    NARCIS (Netherlands)

    van Dijk, Pim; Langers, Dave R M; Moore, BCJ; Patterson, RD; Winter, IM; Carlyon, RP; Gockel, HE

    2013-01-01

    Tonotopy is arguably the most prominent organizational principle in the auditory pathway. Nevertheless, the layout of tonotopic maps in humans is still debated. We present neuroimaging data that robustly identify multiple tonotopic maps in the bilateral auditory cortex. In contrast with some earlier

  1. The Harmonic Organization of Auditory Cortex

    Directory of Open Access Journals (Sweden)

    Xiaoqin eWang

    2013-12-01

    Full Text Available A fundamental structure of sounds encountered in the natural environment is the harmonicity. Harmonicity is an essential component of music found in all cultures. It is also a unique feature of vocal communication sounds such as human speech and animal vocalizations. Harmonics in sounds are produced by a variety of acoustic generators and reflectors in the natural environment, including vocal apparatuses of humans and animal species as well as music instruments of many types. We live in an acoustic world full of harmonicity. Given the widespread existence of the harmonicity in many aspects of the hearing environment, it is natural to expect that it be reflected in the evolution and development of the auditory systems of both humans and animals, in particular the auditory cortex. Recent neuroimaging and neurophysiology experiments have identified regions of non-primary auditory cortex in humans and non-human primates that have selective responses to harmonic pitches. Accumulating evidence has also shown that neurons in many regions of the auditory cortex exhibit characteristic responses to harmonically related frequencies beyond the range of pitch. Together, these findings suggest that a fundamental organizational principle of auditory cortex is based on the harmonicity. Such an organization likely plays an important role in music processing by the brain. It may also form the basis of the preference for particular classes of music and voice sounds.

  2. Primary Auditory Cortex Regulates Threat Memory Specificity

    Science.gov (United States)

    Wigestrand, Mattis B.; Schiff, Hillary C.; Fyhn, Marianne; LeDoux, Joseph E.; Sears, Robert M.

    2017-01-01

    Distinguishing threatening from nonthreatening stimuli is essential for survival and stimulus generalization is a hallmark of anxiety disorders. While auditory threat learning produces long-lasting plasticity in primary auditory cortex (Au1), it is not clear whether such Au1 plasticity regulates memory specificity or generalization. We used…

  3. Hierarchical error representation in medial prefrontal cortex.

    Science.gov (United States)

    Zarr, Noah; Brown, Joshua W

    2016-01-01

    The medial prefrontal cortex (mPFC) is reliably activated by both performance and prediction errors. Error signals have typically been treated as a scalar, and it is unknown to what extent multiple error signals may co-exist within mPFC. Previous studies have shown that lateral frontal cortex (LFC) is arranged in a hierarchy of abstraction, such that more abstract concepts and rules are represented in more anterior cortical regions. Given the close interaction between lateral and medial prefrontal cortex, we explored the hypothesis that mPFC would be organized along a similar rostro-caudal gradient of abstraction, such that more abstract prediction errors are represented further anterior and more concrete errors further posterior. We show that multiple prediction error signals can be found in mPFC, and furthermore, these are arranged in a rostro-caudal gradient of abstraction which parallels that found in LFC. We used a task that requires a three-level hierarchy of rules to be followed, in which the rules changed without warning at each level of the hierarchy. Task feedback indicated which level of the rule hierarchy changed and led to corresponding prediction error signals in mPFC. Moreover, each identified region of mPFC was preferentially functionally connected to correspondingly anterior regions of LFC. These results suggest the presence of a parallel structure between lateral and medial prefrontal cortex, with the medial regions monitoring and evaluating performance based on rules maintained in the corresponding lateral regions.

  4. Contour extracting networks in early extrastriate cortex

    NARCIS (Netherlands)

    Dumoulin, Serge O.; Hess, Robert F.; May, Keith A.; Harvey, Ben M.; Rokers, Bas; Barendregt, Martijn

    2014-01-01

    Neurons in the visual cortex process a local region of visual space, but in order to adequately analyze natural images, neurons need to interact. The notion of an ''association field'' proposes that neurons interact to extract extended contours. Here, we identify the site and properties of contour i

  5. Cortex Matures Faster in Youths With Highest IQ

    Science.gov (United States)

    ... Current Issue Past Issues Research News From NIH Cortex Matures Faster in Youths With Highest IQ Past ... scans showed that their brains' outer mantle, or cortex, thickens more rapidly during childhood, reaching its peak ...

  6. Early and moderate sensory stimulation exerts a protective effect on perilesion representations of somatosensory cortex after focal ischemic damage.

    Science.gov (United States)

    Xerri, Christian; Zennou-Azogui, Yoh'i

    2014-01-01

    Previous studies have shown that intensive training within an early critical time window after focal cortical ischemia increases the area of damaged tissue and is detrimental to behavioral recovery. We postulated that moderate stimulation initiated soon after the lesion could have protective effects on peri-infarct cortical somatotopic representations. Therefore, we have assessed the effects of mild cutaneous stimulation delivered in an attention-demanding behavioral context on the functional organization of the perilesion somatosensory cortex using high-density electrophysiological mapping. We compared the effects of 6-day training initiated on the 3rd day postlesion (early training; ET) to those of same-duration training started on the 8th day (delayed training; DT). Our findings confirm previous work showing that the absence of training aggravates representational loss in the perilesion zone. In addition, ET was found to be sufficient to limit expansion of the ischemic lesion and reduce tissue loss, and substantially maintain the neuronal responsiveness to tactile stimulation, thereby preserving somatotopic map arrangement in the peri-infarct cortical territories. By contrast, DT did not prevent tissue loss and only partially reinstated lost representations in a use-dependent manner within the spared peri-infarct cortical area. This study differentiates the effects of early versus delayed training on perilesion tissue and cortical map reorganization, and underscores the neuroprotective influence of mild rehabilitative stimulation on neuronal response properties in the peri-infarct cortex during an early critical period.

  7. [Raman spectra of monkey cerebral cortex tissue].

    Science.gov (United States)

    Zhu, Ji-chun; Guo, Jian-yu; Cai, Wei-ying; Wang, Zu-geng; Sun, Zhen-rong

    2010-01-01

    Monkey cerebral cortex, an important part in the brain to control action and thought activities, is mainly composed of grey matter and nerve cell. In the present paper, the in situ Raman spectra of the cerebral cortex of the birth, teenage and aged monkeys were achieved for the first time. The results show that the Raman spectra for the different age monkey cerebral cortex exhibit most obvious changes in the regions of 1000-1400 and 2800-3000 cm(-1). With monkey growing up, the relative intensities of the Raman bands at 1313 and 2885 cm(-1) mainly assigned to CH2 chain vibrational mode of lipid become stronger and stronger whereas the relative intensities of the Raman bands at 1338 and 2932 cm(-1) mainly assigned to CH3 chain vibrational mode of protein become weaker and weaker. In addition, the two new Raman bands at 1296 and 2850 cm(-1) are only observed in the aged monkey cerebral cortex, therefore, the two bands can be considered as a character or "marker" to differentiate the caducity degree with monkey growth In order to further explore the changes, the relative intensity ratios of the Raman band at 1313 cm(-1) to that at 1338 cm(-1) and the Raman band at 2885 cm(-1) to that at 2 932 cm(-1), I1313/I1338 and I2885/I2932, which are the lipid-to-protein ratios, are introduced to denote the degree of the lipid content. The results show that the relative intensity ratios increase significantly with monkey growth, namely, the lipid content in the cerebral cortex increases greatly with monkey growth. So, the authors can deduce that the overmuch lipid is an important cause to induce the caducity. Therefore, the results will be a powerful assistance and valuable parameter to study the order of life growth and diagnose diseases.

  8. Olfactory consciousness and gamma oscillation couplings across the olfactory bulb, olfactory cortex, and orbitofrontal cortex

    OpenAIRE

    Kensaku eMori; Hiroyuki eManabe; Kimiya eNarikiyo; Naomi eOnisawa

    2013-01-01

    The orbitofrontal cortex receives multi-modality sensory inputs, including olfactory input, and is thought to be involved in conscious perception of the olfactory image of objects. Generation of olfactory consciousness requires neuronal circuit mechanisms for the ‘binding’ of distributed neuronal activities, with each constituent neuron representing a specific component of an olfactory percept. The shortest neuronal pathway for odor signals to reach the orbitofrontal cortex is olfactory senso...

  9. Premotor cortex modulates somatosensory cortex during voluntary movements without proprioceptive feedback

    DEFF Research Database (Denmark)

    Christensen, Mark Schram; Lundbye-Jensen, Jesper; Geertsen, Svend Sparre;

    2007-01-01

    Movement perception relies on sensory feedback, but the involvement of efference copies remains unclear. We investigated movements without proprioceptive feedback using ischemic nerve block during fMRI in healthy humans, and found preserved activation of the primary somatosensory cortex. This act......Movement perception relies on sensory feedback, but the involvement of efference copies remains unclear. We investigated movements without proprioceptive feedback using ischemic nerve block during fMRI in healthy humans, and found preserved activation of the primary somatosensory cortex...

  10. Projection from the perirhinal cortex to the frontal motor cortex in the rat.

    Science.gov (United States)

    Kyuhou, Shin ichi; Gemba, Hisae

    2002-03-01

    Stimulation of the anterior perirhinal cortex (PERa) induced marked surface-negative and depth-positive field potentials in the rat frontal motor cortex (MC) including the rostral and caudal forelimb areas. Injection of biotinylated dextran into the PERa densely labeled axon terminals in the superficial layers of the MC, where vigorous unit responses were evoked after PERa stimulation, indicated that the perirhinal-frontal projection preferentially activates the superficial layer neurons of the MC.

  11. Orbitofrontal cortex, decision-making and drug addiction

    OpenAIRE

    Schoenbaum, Geoffrey; Roesch, Matthew R.; Stalnaker, Thomas A

    2006-01-01

    The orbitofrontal cortex, as a part of prefrontal cortex, is implicated in executive function. However, within this broad region, the orbitofrontal cortex is distinguished by its unique pattern of connections with crucial subcortical associative learning nodes, such as basolateral amygdala and nucleus accumbens. By virtue of these connections, the orbitofrontal cortex is uniquely positioned to use associative information to project into the future, and to use the value of perceived or expecte...

  12. Wave Patterns in Cell Membrane and Actin Cortex Uncoupled from Chemotactic Signals.

    Science.gov (United States)

    Gerisch, Günther; Ecke, Mary

    2016-01-01

    When cells of Dictyostelium discoideum orientate in a gradient of chemoattractant, they are polarized into a protruding front pointing toward the source of attractant, and into a retracting tail. Under the control of chemotactic signal inputs, Ras is activated and PIP3 is synthesized at the front, while the PIP3-degrading phosphatase PTEN decorates the tail region. As a result of signal transduction, actin filaments assemble at the front into dendritic structures associated with the Arp2/3 complex, in contrast to the tail region where a loose actin meshwork is associated with myosin-II and cortexillin, an antiparallel actin-bundling protein. In axenically growing strains of D. discoideum, wave patterns built by the same components evolve in the absence of any external signal input. Since these autonomously generated patterns are constrained to the plane of the substrate-attached cell surface, they are optimally suited to the optical analysis of state transitions between front-like and tail-like states of the membrane and the actin cortex. Here, we describe imaging techniques using fluorescent proteins to probe for the state of the membrane, the reorganization of the actin network, and the dynamics of wave patterns.

  13. Repetition suppression for speech processing in the associative occipital and parietal cortex of congenitally blind adults.

    Directory of Open Access Journals (Sweden)

    Laureline Arnaud

    Full Text Available In the congenitally blind (CB, sensory deprivation results in cross-modal plasticity, with visual cortical activity observed for various auditory tasks. This reorganization has been associated with enhanced auditory abilities and the recruitment of visual brain areas during sound and language processing. The questions we addressed are whether visual cortical activity might also be observed in CB during passive listening to auditory speech and whether cross-modal plasticity is associated with adaptive differences in neuronal populations compared to sighted individuals (SI. We focused on the neural substrate of vowel processing in CB and SI adults using a repetition suppression (RS paradigm. RS has been associated with enhanced or accelerated neural processing efficiency and synchronous activity between interacting brain regions. We evaluated whether cortical areas in CB were sensitive to RS during repeated vowel processing and whether there were differences across the two groups. In accordance with previous studies, both groups displayed a RS effect in the posterior temporal cortex. In the blind, however, additional occipital, temporal and parietal cortical regions were associated with predictive processing of repeated vowel sounds. The findings suggest a more expanded role for cross-modal compensatory effects in blind persons during sound and speech processing and a functional transfer of specific adaptive properties across neural regions as a consequence of sensory deprivation at birth.

  14. Resting-state functional connectivity in anterior cingulate cortex in normal aging

    Directory of Open Access Journals (Sweden)

    Weifang eCao

    2014-10-01

    Full Text Available Growing evidence suggests that normal aging is associated with cognitive decline and well-maintained emotional well-being. The anterior cingulate cortex (ACC is an important brain region involved in emotional and cognitive processing. We investigated resting-state functional connectivity (FC of two ACC subregions in 30 healthy older adults versus 33 healthy younger adults, by parcellating into rostral (rACC and dorsal (dACC ACC based on clustering of FC profiles. Compared with younger adults, older adults demonstrated greater connection between rACC and anterior insula, suggesting that older adults recruit more proximal dACC brain regions connected with insula to maintain a salient response. Older adults also demonstrated increased FC between rACC and superior temporal gyrus and inferior frontal gyrus, decreased integration between rACC and default mode, and decreased dACC-hippocampal and dACC-thalamic connectivity. These altered FCs reflected rACC and dACC reorganization, and might be related to well emotion regulation and cognitive decline in older adults. Our findings provide further insight into potential functional substrates of emotional and cognitive alterations in the aging brain.

  15. Repetition Suppression for Speech Processing in the Associative Occipital and Parietal Cortex of Congenitally Blind Adults

    Science.gov (United States)

    Arnaud, Laureline; Sato, Marc; Ménard, Lucie; Gracco, Vincent L.

    2013-01-01

    In the congenitally blind (CB), sensory deprivation results in cross-modal plasticity, with visual cortical activity observed for various auditory tasks. This reorganization has been associated with enhanced auditory abilities and the recruitment of visual brain areas during sound and language processing. The questions we addressed are whether visual cortical activity might also be observed in CB during passive listening to auditory speech and whether cross-modal plasticity is associated with adaptive differences in neuronal populations compared to sighted individuals (SI). We focused on the neural substrate of vowel processing in CB and SI adults using a repetition suppression (RS) paradigm. RS has been associated with enhanced or accelerated neural processing efficiency and synchronous activity between interacting brain regions. We evaluated whether cortical areas in CB were sensitive to RS during repeated vowel processing and whether there were differences across the two groups. In accordance with previous studies, both groups displayed a RS effect in the posterior temporal cortex. In the blind, however, additional occipital, temporal and parietal cortical regions were associated with predictive processing of repeated vowel sounds. The findings suggest a more expanded role for cross-modal compensatory effects in blind persons during sound and speech processing and a functional transfer of specific adaptive properties across neural regions as a consequence of sensory deprivation at birth. PMID:23717628

  16. Cholecystokinin from the entorhinal cortex enables neural plasticity in the auditory cortex.

    Science.gov (United States)

    Li, Xiao; Yu, Kai; Zhang, Zicong; Sun, Wenjian; Yang, Zhou; Feng, Jingyu; Chen, Xi; Liu, Chun-Hua; Wang, Haitao; Guo, Yi Ping; He, Jufang

    2014-03-01

    Patients with damage to the medial temporal lobe show deficits in forming new declarative memories but can still recall older memories, suggesting that the medial temporal lobe is necessary for encoding memories in the neocortex. Here, we found that cortical projection neurons in the perirhinal and entorhinal cortices were mostly immunopositive for cholecystokinin (CCK). Local infusion of CCK in the auditory cortex of anesthetized rats induced plastic changes that enabled cortical neurons to potentiate their responses or to start responding to an auditory stimulus that was paired with a tone that robustly triggered action potentials. CCK infusion also enabled auditory neurons to start responding to a light stimulus that was paired with a noise burst. In vivo intracellular recordings in the auditory cortex showed that synaptic strength was potentiated after two pairings of presynaptic and postsynaptic activity in the presence of CCK. Infusion of a CCKB antagonist in the auditory cortex prevented the formation of a visuo-auditory association in awake rats. Finally, activation of the entorhinal cortex potentiated neuronal responses in the auditory cortex, which was suppressed by infusion of a CCKB antagonist. Together, these findings suggest that the medial temporal lobe influences neocortical plasticity via CCK-positive cortical projection neurons in the entorhinal cortex.

  17. Sensitive Dependence of Mental Function on Prefrontal Cortex

    OpenAIRE

    Alen J Salerian

    2015-01-01

    This study offers evidence to suggest that both normalcy and psychiatric illness are sensitively dependent upon prefrontal cortex function. In general, the emergence of psychiatric symptoms coincide with diminished influence of prefrontal cortex function. The mediating influence of prefrontal cortex may be independent of molecular and regional brain dysfunctions contributory to psychiatric illness.

  18. The prefrontal cortex and variants of sequential behaviour: indications of functional differentiation between subdivisions of the rat's prefrontal cortex

    DEFF Research Database (Denmark)

    Mogensen, Jesper; Holm, Søren

    1994-01-01

    Neurobiologi, præfrontal cortex, sekventiel adfærd, rotte, adfærdsprogrammering, informationsbearbejdning......Neurobiologi, præfrontal cortex, sekventiel adfærd, rotte, adfærdsprogrammering, informationsbearbejdning...

  19. Association fiber pathways to the frontal cortex from the superior temporal region in the rhesus monkey

    Energy Technology Data Exchange (ETDEWEB)

    Petrides, M.; Pandya, D.N.

    1988-07-01

    The projections to the frontal cortex that originate from the various areas of the superior temporal region of the rhesus monkey were investigated with the autoradiographic technique. The results demonstrated that the rostral part of the superior temporal gyrus (areas Pro, Ts1, and Ts2) projects to the proisocortical areas of the orbital and medial frontal cortex, as well as to the nearby orbital areas 13, 12, and 11, and to medial areas 9, 10, and 14. These fibers travel to the frontal lobe as part of the uncinate fascicle. The middle part of the superior temporal gyrus (areas Ts3 and paAlt) projects predominantly to the lateral frontal cortex (areas 12, upper 46, and 9) and to the dorsal aspect of the medial frontal lobe (areas 9 and 10). Only a small number of these fibers terminated within the orbitofrontal cortex. The temporofrontal fibers originating from the middle part of the superior temporal gyrus occupy the lower portion of the extreme capsule and lie just dorsal to the fibers of the uncinate fascicle. The posterior part of the superior temporal gyrus projects to the lateral frontal cortex (area 46, dorsal area 8, and the rostralmost part of dorsal area 6). Some of the fibers from the posterior superior temporal gyrus run initially through the extreme capsule and then cross the claustrum as they ascend to enter the external capsule before continuing their course to the frontal lobe. A larger group of fibers curves round the caudalmost Sylvian fissure and travels to the frontal cortex occupying a position just above and medial to the upper branch of the circular sulcus. This latter pathway constitutes a part of the classically described arcuate fasciculus.

  20. Characterization of axo-axonic synapses in the piriform cortex of Mus musculus.

    Science.gov (United States)

    Wang, Xinjun; Sun, Qian-Quan

    2012-03-01

    Previous anatomical and physiological studies have established major glutamatergic and GABAergic neuronal subtypes within the piriform cortical circuits. However, quantitative information regarding axo-axonic inhibitory synapses mediated by chandelier cells across major cortical subdivisions of piriform cortex is lacking. Therefore, we examined the properties of these synapses across the entire piriform cortex. Our results show the following. 1) γ-Aminobutyric acid membrane transporter 1-positive varicosities, whose appearance resembles chandelier cartridges, are found around the initial segments of axons of glutamatergic cells across layers II and III. 2) Both the density of axo-axonic cartridges and the degree of γ-aminobutyric acid membrane transporter 1 innervation in each axo-axonic synapse are significantly higher in the piriform cortex than in the neocortex. 3) Glutamate decarboxylase 67, vesicular GABA transporter, and parvalbumin, but not calbindin, are colocalized with the presynaptic varicosities, whereas gephyrin, Na-K-2Cl cotransporter 1, and GABA(A) receptor α1 subunit, but not K-Cl cotransporter 2, are colocalized at the presumed postsynaptic sites. 4) The axo-axonic cartridges innervate the majority of excitatory neurons and are distributed more frequently in putative centrifugal cells and posterior piriform cortex. We further describe the morphology of chandelier cells by using parvalbumin-immunoreactivity and single-cell labeling. In summary, our results demonstrate that a small population of chandelier cells mediates abundant axo-axonic synapses across the entire piriform cortex. Because of the critical location of these inhibitory synapses in relation to action potential regulation, our results highlight a critical role of axo-axonic synapses in regulating information flow and olfactory-related oscillations within the piriform cortex in vivo.

  1. Projections from Orbitofrontal Cortex to Anterior Piriform Cortex in the Rat Suggest a Role in Olfactory Information Processing

    OpenAIRE

    ILLIG, KURT R.

    2005-01-01

    The orbitofrontal cortex (OFC) has been characterized as a higher-order, multimodal sensory cortex. Evidence from electrophysiological and behavioral studies in the rat has suggested that OFC plays a role in modulating olfactory guided behavior, and a significant projection to OFC arises from piriform cortex, the traditional primary olfactory cortex. To discern how OFC interacts with primary olfactory structures, the anterograde tracer Phaseolus vulgaris leucoagglutinin was injected into orbi...

  2. Reorganization of Damaged Chromatin by the Exchange of Histone Variant H2A.Z-2

    Energy Technology Data Exchange (ETDEWEB)

    Nishibuchi, Ikuno [Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima (Japan); Department of Radiation Oncology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima (Japan); Department of Radiation Oncology, Hiroshima Prefectural Hospital, Hiroshima (Japan); Suzuki, Hidekazu; Kinomura, Aiko; Sun, Jiying; Liu, Ning-Ang [Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima (Japan); Horikoshi, Yasunori [Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima (Japan); Research Center for Mathematics of Chromatin Live Dynamics, Hiroshima University, Hiroshima (Japan); Shima, Hiroki [Department of Biochemistry, Graduate School of Medical Sciences, Tohoku University, Sendai (Japan); Kusakabe, Masayuki; Harata, Masahiko [Laboratory of Molecular Biology, Graduate School of Agricultural Science, Tohoku University, Sendai (Japan); Fukagawa, Tatsuo [Department of Molecular Genetics, National Institute of Genetics and The Graduate University for Advanced Studies, Mishima (Japan); Ikura, Tsuyoshi [Laboratory of Chromatin Regulatory Network, Department of Mutagenesis, Radiation Biology Center, Kyoto University, Kyoto (Japan); Ishida, Takafumi [Department of Cardiovascular Medicine, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima (Japan); Nagata, Yasushi [Department of Radiation Oncology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima (Japan); Tashiro, Satoshi, E-mail: ktashiro@hiroshima-u.ac.jp [Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima (Japan); Research Center for Mathematics of Chromatin Live Dynamics, Hiroshima University, Hiroshima (Japan)

    2014-07-15

    Purpose: The reorganization of damaged chromatin plays an important role in the regulation of the DNA damage response. A recent study revealed the presence of 2 vertebrate H2A.Z isoforms, H2A.Z-1 and H2A.Z-2. However, the roles of the vertebrate H2A.Z isoforms are still unclear. Thus, in this study we examined the roles of the vertebrate H2A.Z isoforms in chromatin reorganization after the induction of DNA double-strand breaks (DSBs). Methods and Materials: To examine the dynamics of H2A.Z isoforms at damaged sites, we constructed GM0637 cells stably expressing each of the green fluorescent protein (GFP)-labeled H2A.Z isoforms, and performed fluorescence recovery after photobleaching (FRAP) analysis and inverted FRAP analysis in combination with microirradiation. Immunofluorescence staining using an anti-RAD51 antibody was performed to study the kinetics of RAD51 foci formation after 2-Gy irradiation of wild-type (WT), H2A.Z-1- and H2A.Z-2-deficient DT40 cells. Colony-forming assays were also performed to compare the survival rates of WT, H2A.Z-1-, and H2A.Z-2-deficient DT40 cells with control, and H2A.Z-1- and H2A.Z-2-depleted U2OS cells after irradiation. Results: FRAP analysis revealed that H2A.Z-2 was incorporated into damaged chromatin just after the induction of DSBs, whereas H2A.Z-1 remained essentially unchanged. Inverted FRAP analysis showed that H2A.Z-2 was released from damaged chromatin. These findings indicated that H2A.Z-2 was exchanged at DSB sites immediately after the induction of DSBs. RAD51 focus formation after ionizing irradiation was disturbed in H2A.Z-2-deficient DT40 cells but not in H2A.Z-1-deficient cells. The survival rate of H2A.Z-2-deficient cells after irradiation was lower than those of WT and H2A.Z-1- DT40 cells. Similar to DT40 cells, H2A.Z-2-depleted U2OS cells were also radiation-sensitive compared to control and H2A.Z-1-depleted cells. Conclusions: We found that vertebrate H2A.Z-2 is involved in the regulation of the DNA

  3. Signed words in the congenitally deaf evoke typical late lexicosemantic responses with no early visual responses in left superior temporal cortex.

    Science.gov (United States)

    Leonard, Matthew K; Ferjan Ramirez, Naja; Torres, Christina; Travis, Katherine E; Hatrak, Marla; Mayberry, Rachel I; Halgren, Eric

    2012-07-11

    Congenitally deaf individuals receive little or no auditory input, and when raised by deaf parents, they acquire sign as their native and primary language. We asked two questions regarding how the deaf brain in humans adapts to sensory deprivation: (1) is meaning extracted and integrated from signs using the same classical left hemisphere frontotemporal network used for speech in hearing individuals, and (2) in deafness, is superior temporal cortex encompassing primary and secondary auditory regions reorganized to receive and process visual sensory information at short latencies? Using MEG constrained by individual cortical anatomy obtained with MRI, we examined an early time window associated with sensory processing and a late time window associated with lexicosemantic integration. We found that sign in deaf individuals and speech in hearing individuals activate a highly similar left frontotemporal network (including superior temporal regions surrounding auditory cortex) during lexicosemantic processing, but only speech in hearing individuals activates auditory regions during sensory processing. Thus, neural systems dedicated to processing high-level linguistic information are used for processing language regardless of modality or hearing status, and we do not find evidence for rewiring of afferent connections from visual systems to auditory cortex.

  4. [Functional connectivity of resting-state functional magnetic resonance imaging observation of the right side of the auditory cortex of sudden deafness].

    Science.gov (United States)

    Zhu, Xin; Huang, Zhichun; Liu, Bin; Yang, Ming; Ji, Hui

    2013-04-01

    Positively related to functional connectivity using resting state fMRI functional connectivity method to observe the right of sudden deafness of auditory cortex in patients with brain. We selected the right side of the 12 cases of patients with sudden deafness resting state fMRI data acquisition, positive correlation function for the observation about the right of sudden deafness patients using the method of functional connectivity brain auditory cortex and the brain regions to connect brain map, and matched the normal hearing group the difference. The right side of sudden deafness in patients with valid data for the seed point of A I bilateral. The brain was activated network included bilateral transverse gyrus, superior temporal gyrus, insula, cingulate gyrus and supplementary motor area. Brain networks were activated like a normal person, but there were differences between the two. The right side of the deafness of A I seed point the functional connectivity of the auditory system is still mainly confined to the auditory system, but the local auditory cortex functional reorganization occurs.

  5. Neurofisiologia e plasticidade no córtex cerebral pela estimulação magnética transcraniana repetitiva Plasticity of the human cerebral cortex as revealed by transcranial magnetic stimulation

    Directory of Open Access Journals (Sweden)

    Joaquim Brasil Neto

    2004-01-01

    Full Text Available Um velho dogma da biologia afirma que só existiria capacidade de reorganização cortical (neuroplasticidade em animais muito jovens; no adulto, tal capacidade seria pequena ou mesmo inexistente. Aqui, revisamos estudos realizados em animais e em humanos que demonstram uma capacidade de reorganização cortical nos sistemas sensoriais e motores em indivíduos adultos. Destacamos os estudos realizados com a técnica de estimulação magnética transcraniana. O córtex cerebral asulto é capaz de reorganização após lesões do sistema nervoso periférico ou central ou no contexto do aprendizado.An old biological dogma states that a potencial for cortical reorganization (neuroplasticity exists nly in young animals, being lost in adlt life. Here we review studies carried out both in animals and humans, whixh demonstrate cortical reorganization in sensory and motor systems in adult subjects. We particulary emphasiza human studies carried out with the aid of transcranial magnetic stimulation. The adult cortex is capable of reorganization after peripheral or central nervous system lesions and as a result of learning.

  6. Remote Cortical Reorganization following Sub-Cortical Infarction:A Preliminary Voxel-Based Morphometric Study%皮层下梗死远隔皮层重塑VBM初步研究

    Institute of Scientific and Technical Information of China (English)

    蔡建新; 冀旗玲; 那旭; 李坤成

    2014-01-01

    目的 利用基于体素的形态学测量(VBM)方法,探讨皮层下梗死患者远隔部位的脑灰质结构重塑及其与运动预后的关系.方法 对11例皮层下梗死患者分别于发病5天内、3个月后行高分辨率MRI全脑容积扫描,并进行美国国立卫生院卒中量表(NIHSS)和运动力指数(MI)评估,应用VBM方法计算患者急性期、陈旧期全脑灰质体积的差异,并分析其与康复指标的相关性.结果 陈旧期时患侧中央前回、中扣带回及健侧小脑Ⅵ区、Crus1灰质体积明显减少,而健侧中央前回、眶额回、腹侧前额叶及患侧小脑Crus1灰质体积增加,且双侧中央前回、健侧小脑Ⅵ区、眶额回灰质体积与康复评分(NIHSS和MI)相关.结论 皮层下脑梗死后存在广泛的远隔皮层重塑,可能与患者预后相关,进一步的研究对揭示梗死后神经功能恢复机制具有重要意义.%Objective To investigate the reorganization in remote cerebral areas after sub-cortical infarction by using a longitudinal voxel-based gray matter volume (GMV) analysis.Methods Eleven patients with ischemic stroke that involved sub-cortical regions underwent structural magnetic resonance imaging (MRI) within 5 days and three months after the onset of the infarction.The patients were evaluated using National Institutes of Health Stroke Scale (NIHSS) and Motricity Index (MI).Using VBM method the GMV of the acute stage and chronic stage was calculated and the results were compared between the two stages.The correlation between GMV and rehabilitation indexes (NIHSS and MI) was analyzed.Results Compared with the acute stage,significant decrease in GMV was found in the ipsi-lateral precentral gyrus (PreCG),midcingulate cortex and contralesional cerebellar lobule Ⅵ (CBVI),cerebellar lobule Crus 1 in the chronic stage,while significant increase in GMV was seen in the contra-lateral precentral gyrus,orbitofrontal cortex (OFC),ventral prefrontal cortex,and ipsi

  7. Social distance evaluation in human parietal cortex.

    Science.gov (United States)

    Yamakawa, Yoshinori; Kanai, Ryota; Matsumura, Michikazu; Naito, Eiichi

    2009-01-01

    Across cultures, social relationships are often thought of, described, and acted out in terms of physical space (e.g. "close friends" "high lord"). Does this cognitive mapping of social concepts arise from shared brain resources for processing social and physical relationships? Using fMRI, we found that the tasks of evaluating social compatibility and of evaluating physical distances engage a common brain substrate in the parietal cortex. The present study shows the possibility of an analytic brain mechanism to process and represent complex networks of social relationships. Given parietal cortex's known role in constructing egocentric maps of physical space, our present findings may help to explain the linguistic, psychological and behavioural links between social and physical space.

  8. Determining physical properties of the cell cortex

    CERN Document Server

    Saha, A; Behrndt, M; Heisenberg, C -P; Jülicher, F; Grill, S W

    2015-01-01

    Actin and myosin assemble into a thin layer of a highly dynamic network underneath the membrane of eukaryotic cells. This network generates the forces that drive cell and tissue-scale morphogenetic processes. The effective material properties of this active network determine large-scale deformations and other morphogenetic events. For example,the characteristic time of stress relaxation (the Maxwell time)in the actomyosin sets the time scale of large-scale deformation of the cortex. Similarly, the characteristic length of stress propagation (the hydrodynamic length) sets the length scale of slow deformations, and a large hydrodynamic length is a prerequisite for long-ranged cortical flows. Here we introduce a method to determine physical parameters of the actomyosin cortical layer (in vivo). For this we investigate the relaxation dynamics of the cortex in response to laser ablation in the one-cell-stage {\\it C. elegans} embryo and in the gastrulating zebrafish embryo. These responses can be interpreted using ...

  9. Apraxia, pantomime and the parietal cortex

    Directory of Open Access Journals (Sweden)

    E. Niessen

    2014-01-01

    In contrast to previous suggestions, current analyses show that both lesion and functional studies support the notion of a left-hemispheric fronto-(temporal-parietal network underlying pantomiming object use. Furthermore, our review demonstrates that the left parietal cortex plays a key role in pantomime-related processes. More specifically, stringently controlled fMRI-studies suggest that in addition to storing motor schemas, left parietal cortex is also involved in activating these motor schemas in the context of pantomiming object use. In addition to inherent differences between structural and functional imaging studies and consistent with the dedifferentiation hypothesis, the age difference between young healthy subjects (typically included in functional imaging studies and elderly neurological patients (typically included in structural lesion studies may well contribute to the finding of a more distributed representation of pantomiming within the motor-dominant left hemisphere in the elderly.

  10. Monkey cortex through fMRI glasses.

    Science.gov (United States)

    Vanduffel, Wim; Zhu, Qi; Orban, Guy A

    2014-08-06

    In 1998 several groups reported the feasibility of fMRI experiments in monkeys, with the goal to bridge the gap between invasive nonhuman primate studies and human functional imaging. These studies yielded critical insights in the neuronal underpinnings of the BOLD signal. Furthermore, the technology has been successful in guiding electrophysiological recordings and identifying focal perturbation targets. Finally, invaluable information was obtained concerning human brain evolution. We here provide a comprehensive overview of awake monkey fMRI studies mainly confined to the visual system. We review the latest insights about the topographic organization of monkey visual cortex and discuss the spatial relationships between retinotopy and category- and feature-selective clusters. We briefly discuss the functional layout of parietal and frontal cortex and continue with a summary of some fascinating functional and effective connectivity studies. Finally, we review recent comparative fMRI experiments and speculate about the future of nonhuman primate imaging.

  11. Effects of aging on motor cortex excitability.

    Science.gov (United States)

    Oliviero, A; Profice, P; Tonali, P A; Pilato, F; Saturno, E; Dileone, M; Ranieri, F; Di Lazzaro, V

    2006-05-01

    To determine whether aging is associated with changes in excitability of the cerebral cortex, we evaluated the excitability of the motor cortex with transcranial magnetic stimulation (TMS). We compared TMS related measures obtained in a group of young people with those of a group of old people. Motor evoked potential (MEP) amplitude was significantly smaller in older than in younger controls (1.3+/-0.8 mV versus 2.7+/-1.1 mV; p<0.0071). Mean cortical silent period (CSP) duration was shorter in older than in younger controls (87+/-29 ms versus 147+/-39 ms; p<0.0071). SP duration/MEP amplitude ratios were similar in both groups. Our results are consistent with an impaired efficiency of some intracortical circuits in old age.

  12. Orbitofrontal Cortex, Associative Learning, and Expectancies

    Science.gov (United States)

    Schoenbaum, Geoffrey; Roesch, Matthew

    2009-01-01

    Orbitofrontal cortex is characterized by its unique pattern of connections with subcortical areas, such as basolateral amygdala. Here we distinguish between the critical role of these areas in associative learning and the pivotal contribution of OFC to the manipulation of this information to control behavior. This contribution reflects the ability of OFC to signal the desirability of expected outcomes, which requires the integration of associative information with information concerning internal states and goals in representational memory. PMID:16129393

  13. Working Memory in the Prefrontal Cortex

    Directory of Open Access Journals (Sweden)

    Shintaro Funahashi

    2017-04-01

    Full Text Available The prefrontal cortex participates in a variety of higher cognitive functions. The concept of working memory is now widely used to understand prefrontal functions. Neurophysiological studies have revealed that stimulus-selective delay-period activity is a neural correlate of the mechanism for temporarily maintaining information in working memory processes. The central executive, which is the master component of Baddeley’s working memory model and is thought to be a function of the prefrontal cortex, controls the performance of other components by allocating a limited capacity of memory resource to each component based on its demand. Recent neurophysiological studies have attempted to reveal how prefrontal neurons achieve the functions of the central executive. For example, the neural mechanisms of memory control have been examined using the interference effect in a dual-task paradigm. It has been shown that this interference effect is caused by the competitive and overloaded recruitment of overlapping neural populations in the prefrontal cortex by two concurrent tasks and that the information-processing capacity of a single neuron is limited to a fixed level, can be flexibly allocated or reallocated between two concurrent tasks based on their needs, and enhances behavioral performance when its allocation to one task is increased. Further, a metamemory task requiring spatial information has been used to understand the neural mechanism for monitoring its own operations, and it has been shown that monitoring the quality of spatial information represented by prefrontal activity is an important factor in the subject's choice and that the strength of spatially selective delay-period activity reflects confidence in decision-making. Although further studies are needed to elucidate how the prefrontal cortex controls memory resource and supervises other systems, some important mechanisms related to the central executive have been identified.

  14. Processing of sound location in human cortex.

    Science.gov (United States)

    Lewald, Jörg; Riederer, Klaus A J; Lentz, Tobias; Meister, Ingo G

    2008-03-01

    This functional magnetic resonance imaging study was focused on the neural substrates underlying human auditory space perception. In order to present natural-like sound locations to the subjects, acoustic stimuli convolved with individual head-related transfer functions were used. Activation foci, as revealed by analyses of contrasts and interactions between sound locations, formed a complex network, including anterior and posterior regions of temporal lobe, posterior parietal cortex, dorsolateral prefrontal cortex and inferior frontal cortex. The distinct topography of this network was the result of different patterns of activation and deactivation, depending on sound location, in the respective voxels. These patterns suggested different levels of complexity in processing of auditory spatial information, starting with simple left/right discrimination in the regions surrounding the primary auditory cortex, while the integration of information on hemispace and eccentricity of sound may take place at later stages. Activations were identified as being located in regions assigned to both the dorsal and ventral auditory cortical streams, that are assumed to be preferably concerned with analysis of spatial and non-spatial sound features, respectively. The finding of activations also in the ventral stream could, on the one hand, reflect the well-known functional duality of auditory spectral analysis, that is, the concurrent extraction of information based on location (due to the spectrotemporal distortions caused by head and pinnae) and spectral characteristics of a sound source. On the other hand, this result may suggest the existence of shared neural networks, performing analyses of auditory 'higher-order' cues for both localization and identification of sound sources.

  15. The role of prefrontal cortex in psychopathy

    OpenAIRE

    Koenigs, Michael

    2012-01-01

    Psychopathy is a personality disorder characterized by remorseless and impulsive antisocial behavior. Given the significant societal costs of the recidivistic criminal activity associated with the disorder, there is a pressing need for more effective treatment strategies, and hence, a better understanding of the psychobiological mechanisms underlying the disorder. The prefrontal cortex (PFC) is likely to play an important role in psychopathy. In particular, the ventromedial and anterior cingu...

  16. Parallel driving and modulatory pathways link the prefrontal cortex and thalamus.

    Directory of Open Access Journals (Sweden)

    Basilis Zikopoulos

    Full Text Available Pathways linking the thalamus and cortex mediate our daily shifts from states of attention to quiet rest, or sleep, yet little is known about their architecture in high-order neural systems associated with cognition, emotion and action. We provide novel evidence for neurochemical and synaptic specificity of two complementary circuits linking one such system, the prefrontal cortex with the ventral anterior thalamic nucleus in primates. One circuit originated from the neurochemical group of parvalbumin-positive thalamic neurons and projected focally through large terminals to the middle cortical layers, resembling 'drivers' in sensory pathways. Parvalbumin thalamic neurons, in turn, were innervated by small 'modulatory' type cortical terminals, forming asymmetric (presumed excitatory synapses at thalamic sites enriched with the specialized metabotropic glutamate receptors. A second circuit had a complementary organization: it originated from the neurochemical group of calbindin-positive thalamic neurons and terminated through small 'modulatory' terminals over long distances in the superficial prefrontal layers. Calbindin thalamic neurons, in turn, were innervated by prefrontal axons through small and large terminals that formed asymmetric synapses preferentially at sites with ionotropic glutamate receptors, consistent with a driving pathway. The largely parallel thalamo-cortical pathways terminated among distinct and laminar-specific neurochemical classes of inhibitory neurons that differ markedly in inhibitory control. The balance of activation of these parallel circuits that link a high-order association cortex with the thalamus may allow shifts to different states of consciousness, in processes that are disrupted in psychiatric diseases.

  17. Specialized elements of orbitofrontal cortex in primates.

    Science.gov (United States)

    Barbas, Helen

    2007-12-01

    The orbitofrontal cortex is associated with encoding the significance of stimuli within an emotional context, and its connections can be understood in this light. This large cortical region is architectonically heterogeneous, but its connections and functions can be summarized by a broad grouping of areas by cortical type into posterior and anterior sectors. The posterior (limbic) orbitofrontal region is composed of agranular and dysgranular-type cortices and has unique connections with primary olfactory areas and rich connections with high-order sensory association cortices. Posterior orbitofrontal areas are further distinguished by dense and distinct patterns of connections with the amygdala and memory-related anterior temporal lobe structures that may convey signals about emotional import and their memory. The special sets of connections suggest that the posterior orbitofrontal cortex is the primary region for the perception of emotions. In contrast to orbitofrontal areas, posterior medial prefrontal areas in the anterior cingulate are not multi-modal, but have strong connections with auditory association cortices, brain stem vocalization, and autonomic structures, in pathways that may mediate emotional communication and autonomic activation in emotional arousal. Posterior orbitofrontal areas communicate with anterior orbitofrontal areas and, through feedback projections, with lateral prefrontal and other cortices, suggesting a sequence of information processing for emotions. Pathology in orbitofrontal cortex may remove feedback input to sensory cortices, dissociating emotional context from sensory content and impairing the ability to interpret events.

  18. Emotion, decision making and the orbitofrontal cortex.

    Science.gov (United States)

    Bechara, A; Damasio, H; Damasio, A R

    2000-03-01

    The somatic marker hypothesis provides a systems-level neuroanatomical and cognitive framework for decision making and the influence on it by emotion. The key idea of this hypothesis is that decision making is a process that is influenced by marker signals that arise in bioregulatory processes, including those that express themselves in emotions and feelings. This influence can occur at multiple levels of operation, some of which occur consciously and some of which occur non-consciously. Here we review studies that confirm various predictions from the hypothesis. The orbitofrontal cortex represents one critical structure in a neural system subserving decision making. Decision making is not mediated by the orbitofrontal cortex alone, but arises from large-scale systems that include other cortical and subcortical components. Such structures include the amygdala, the somatosensory/insular cortices and the peripheral nervous system. Here we focus only on the role of the orbitofrontal cortex in decision making and emotional processing, and the relationship between emotion, decision making and other cognitive functions of the frontal lobe, namely working memory.

  19. Binocular form deprivation influences the visual cortex

    Institute of Scientific and Technical Information of China (English)

    Mingming Liu; Chuanhuang Weng; Hanping Xie; Wei Qin

    2012-01-01

    1a-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors are considered to play a crucial role in synaptic plasticity in the developing visual cortex. In this study, we established a rat model of binocular form deprivation by suturing the rat binocular eyelids before eye-opening at postnatal day 14. During development, the decay time of excitatory postsynaptic currents mediated by 1a-amino-3- hydroxy-5-methyl-4-isoxazolepropionic acid receptors of normal rats became longer after eyeopening; however, the decay time did not change significantly in binocular form deprivation rats. The peak value in the normal group became gradually larger with age, but there was no significant change in the binocular form deprivation group. These findings indicate that binocular form deprivation influences the properties of excitatory postsynaptic currents mediated by β-amino-3- hydroxy-5-methyl-4-isoxazolepropionic acid receptors in the rat visual cortex around the end of the critical period, indicating that form stimulation is associated with the experience-dependent modification of neuronal synapses in the visual cortex.

  20. Rhythmic spontaneous activity in the piriform cortex.

    Science.gov (United States)

    Sanchez-Vives, Maria V; Descalzo, V F; Reig, R; Figueroa, N A; Compte, A; Gallego, R

    2008-05-01

    Slow spontaneous rhythmic activity is generated and propagates in neocortical slices when bathed in an artificial cerebrospinal fluid with ionic concentrations similar to the ones in vivo. This activity is extraordinarily similar to the activation of the cortex in physiological conditions (e.g., slow-wave sleep), thus representing a unique in vitro model to understand how cortical networks maintain and control ongoing activity. Here we have characterized the activity generated in the olfactory or piriform cortex and endopiriform nucleus (piriform network). Because these structures are prone to generate epileptic discharges, it seems critical to understand how they generate and regulate their physiological rhythmic activity. The piriform network gave rise to rhythmic spontaneous activity consisting of a succession of up and down states at an average frequency of 1.8 Hz, qualitatively similar to the corresponding neocortical activity. This activity originated in the deep layers of the piriform network, which displayed higher excitability and denser connectivity. A remarkable difference with neocortical activity was the speed of horizontal propagation (114 mm/s), one order of magnitude faster in the piriform network. Properties of the piriform cortex subserving fast horizontal propagation may underlie the higher vulnerability of this area to epileptic seizures.

  1. An integrator circuit in cerebellar cortex.

    Science.gov (United States)

    Maex, Reinoud; Steuber, Volker

    2013-09-01

    The brain builds dynamic models of the body and the outside world to predict the consequences of actions and stimuli. A well-known example is the oculomotor integrator, which anticipates the position-dependent elasticity forces acting on the eye ball by mathematically integrating over time oculomotor velocity commands. Many models of neural integration have been proposed, based on feedback excitation, lateral inhibition or intrinsic neuronal nonlinearities. We report here that a computational model of the cerebellar cortex, a structure thought to implement dynamic models, reveals a hitherto unrecognized integrator circuit. In this model, comprising Purkinje cells, molecular layer interneurons and parallel fibres, Purkinje cells were able to generate responses lasting more than 10 s, to which both neuronal and network mechanisms contributed. Activation of the somatic fast sodium current by subthreshold voltage fluctuations was able to maintain pulse-evoked graded persistent activity, whereas lateral inhibition among Purkinje cells via recurrent axon collaterals further prolonged the responses to step and sine wave stimulation. The responses of Purkinje cells decayed with a time-constant whose value depended on their baseline spike rate, with integration vanishing at low ( 30 per s). The model predicts that the apparently fast circuit of the cerebellar cortex may control the timing of slow processes without having to rely on sensory feedback. Thus, the cerebellar cortex may contain an adaptive temporal integrator, with the sensitivity of integration to the baseline spike rate offering a potential mechanism of plasticity of the response time-constant.

  2. Hierarchical Bayesian inference in the visual cortex

    Science.gov (United States)

    Lee, Tai Sing; Mumford, David

    2003-07-01

    Traditional views of visual processing suggest that early visual neurons in areas V1 and V2 are static spatiotemporal filters that extract local features from a visual scene. The extracted information is then channeled through a feedforward chain of modules in successively higher visual areas for further analysis. Recent electrophysiological recordings from early visual neurons in awake behaving monkeys reveal that there are many levels of complexity in the information processing of the early visual cortex, as seen in the long-latency responses of its neurons. These new findings suggest that activity in the early visual cortex is tightly coupled and highly interactive with the rest of the visual system. They lead us to propose a new theoretical setting based on the mathematical framework of hierarchical Bayesian inference for reasoning about the visual system. In this framework, the recurrent feedforward/feedback loops in the cortex serve to integrate top-down contextual priors and bottom-up observations so as to implement concurrent probabilistic inference along the visual hierarchy. We suggest that the algorithms of particle filtering and Bayesian-belief propagation might model these interactive cortical computations. We review some recent neurophysiological evidences that support the plausibility of these ideas. 2003 Optical Society of America

  3. Does intrinsic motivation enhance motor cortex excitability?

    Science.gov (United States)

    Radel, Rémi; Pjevac, Dusan; Davranche, Karen; d'Arripe-Longueville, Fabienne; Colson, Serge S; Lapole, Thomas; Gruet, Mathieu

    2016-11-01

    Intrinsic motivation (IM) is often viewed as a spontaneous tendency for action. Recent behavioral and neuroimaging evidence indicate that IM, in comparison to extrinsic motivation (EM), solicits the motor system. Accordingly, we tested whether IM leads to greater excitability of the motor cortex than EM. To test this hypothesis, we used two different tasks to induce the motivational orientation using either words representing each motivational orientation or pictures previously linked to each motivational orientation through associative learning. Single-pulse transcranial magnetic stimulation over the motor cortex was applied when viewing the stimuli. Electromyographic activity was recorded on the contracted first dorsal interosseous muscle. Two indexes of corticospinal excitability (the amplitude of motor-evoked potential and the length of cortical silent period) were obtained through unbiased automatic detection and analyzed using a mixed model that provided both statistical power and a high level of control over all important individual, task, and stimuli characteristics. Across the two tasks and the two indices of corticospinal excitability, the exposure to IM-related stimuli did not lead to a greater corticospinal excitability than EM-related stimuli or than stimuli with no motivational valence (ps > .20). While these results tend to dismiss the advantage of IM at activating the motor cortex, we suggest alternative hypotheses to explain this lack of effect, which deserves further research. © 2016 Society for Psychophysiological Research.

  4. Functional maps of human auditory cortex: effects of acoustic features and attention.

    Directory of Open Access Journals (Sweden)

    David L Woods

    Full Text Available BACKGROUND: While human auditory cortex is known to contain tonotopically organized auditory cortical fields (ACFs, little is known about how processing in these fields is modulated by other acoustic features or by attention. METHODOLOGY/PRINCIPAL FINDINGS: We used functional magnetic resonance imaging (fMRI and population-based cortical surface analysis to characterize the tonotopic organization of human auditory cortex and analyze the influence of tone intensity, ear of delivery, scanner background noise, and intermodal selective attention on auditory cortex activations. Medial auditory cortex surrounding Heschl's gyrus showed large sensory (unattended activations with two mirror-symmetric tonotopic fields similar to those observed in non-human primates. Sensory responses in medial regions had symmetrical distributions with respect to the left and right hemispheres, were enlarged for tones of increased intensity, and were enhanced when sparse image acquisition reduced scanner acoustic noise. Spatial distribution analysis suggested that changes in tone intensity shifted activation within isofrequency bands. Activations to monaural tones were enhanced over the hemisphere contralateral to stimulation, where they produced activations similar to those produced by binaural sounds. Lateral regions of auditory cortex showed small sensory responses that were larger in the right than left hemisphere, lacked tonotopic organization, and were uninfluenced by acoustic parameters. Sensory responses in both medial and lateral auditory cortex decreased in magnitude throughout stimulus blocks. Attention-related modulations (ARMs were larger in lateral than medial regions of auditory cortex and appeared to arise primarily in belt and parabelt auditory fields. ARMs lacked tonotopic organization, were unaffected by acoustic parameters, and had distributions that were distinct from those of sensory responses. Unlike the gradual adaptation seen for sensory responses

  5. Reorganizing nursing work on surgical units: a time-and-motion study.

    Science.gov (United States)

    Desjardins, France; Cardinal, Linda; Belzile, Eric; McCusker, Jane

    2008-01-01

    A time-and-motion study was conducted in response to perceptions that the surgical nursing staff at a Montreal hospital was spending an excessive amount of time on non-nursing care. A sample of 30 nurse shifts was observed by trained observers who timed nurses' activities for their entire working shift using a hand-held Personal Digital Assistant. Activities were grouped into four main categories: direct patient care, indirect patient care, non-nursing and personal activities. Break and meal times were excluded from the denominator of total worked hours. A total of 201 working hours were observed, an average of 6 hours, 42 minutes per nurse shift. The mean proportions of each nurse shift spent on the main activity categories were: direct care 32.8%, indirect care 55.7%, non-nursing tasks 9.0% and personal 2.5%. Three activities (communication among health professionals, medication verification/preparation and documentation) comprised 78.9% of indirect care time. Greater time on indirect care was associated with work on night shifts and on the short-stay surgical unit. Subsequent work reorganization focused on reducing time spent on communication and medications. The authors conclude that time-and-motion studies are a useful method of monitoring appropriate use of nursing staff, and may provide results that assist in restructuring nursing tasks.

  6. Dopamine receptor activation reorganizes neuronal ensembles during hippocampal sharp waves in vitro.

    Directory of Open Access Journals (Sweden)

    Takeyuki Miyawaki

    Full Text Available Hippocampal sharp wave (SW/ripple complexes are thought to contribute to memory consolidation. Previous studies suggest that behavioral rewards facilitate SW occurrence in vivo. However, little is known about the precise mechanism underlying this enhancement. Here, we examined the effect of dopaminergic neuromodulation on spontaneously occurring SWs in acute hippocampal slices. Local field potentials were recorded from the CA1 region. A brief (1 min treatment with dopamine led to a persistent increase in the event frequency and the magnitude of SWs. This effect lasted at least for our recording period of 45 min and did not occur in the presence of a dopamine D1/D5 receptor antagonist. Functional multineuron calcium imaging revealed that dopamine-induced SW augmentation was associated with an enriched repertoire of the firing patterns in SW events, whereas the overall tendency of individual neurons to participate in SWs and the mean number of cells participating in a single SW were maintained. Therefore, dopaminergic activation is likely to reorganize cell assemblies during SWs.

  7. Distinct impact of targeted actin cytoskeleton reorganization on mechanical properties of normal and malignant cells.

    Science.gov (United States)

    Efremov, Yu M; Dokrunova, A A; Efremenko, A V; Kirpichnikov, M P; Shaitan, K V; Sokolova, O S

    2015-11-01

    The actin cytoskeleton is substantially modified in cancer cells because of changes in actin-binding protein abundance and functional activity. As a consequence, cancer cells have distinctive motility and mechanical properties, which are important for many processes, including invasion and metastasis. Here, we studied the effects of actin cytoskeleton alterations induced by specific nucleation inhibitors (SMIFH2, CK-666), cytochalasin D, Y-27632 and detachment from the surface by trypsinization on the mechanical properties of normal Vero and prostate cancer cell line DU145. The Young's modulus of Vero cells was 1300±900 Pa, while the prostate cancer cell line DU145 exhibited significantly lower Young's moduli (600±400 Pa). The Young's moduli exhibited a log-normal distribution for both cell lines. Unlike normal cells, cancer cells demonstrated diverse viscoelastic behavior and different responses to actin cytoskeleton reorganization. They were more resistant to specific formin-dependent nucleation inhibition, and reinforced their cortical actin after detachment from the substrate. This article is part of a Special Issue entitled: Mechanobiology.

  8. Cyclooxygenase-2 inhibitor inhibits hippocampal synaptic reorganization in pilocarpine-induced status epilepticus rats

    Institute of Scientific and Technical Information of China (English)

    Hai-ju ZHANG; Ruo-peng SUN; Ge-fei LEI; Lu YANG; Chun-xi LIU

    2008-01-01

    Objective: To examine modulations caused by cyclooxygenase-2 (COX-2) inhibitors on altered microenvironments and overbalanced neurotransmitters in pilocarpine-induced epileptic status rats and to investigate possible mechanisms. Methods:Celecoxib (a COX-2 inhibitor) was administered 45 min prior to pilocarpine administration. The effects of COX-2 inhibitors on mIPSCs (miniature GABAergic inhibitory postsynaptic currents) of CA3 pyramidal cells in the hippocampus were recorded. Expressions of COX-2, c-Fos, newly generated neurons, and activated microgliosis wore analyzed by immunohistochemistry, and expressions of α-subunit of γ-amino butyric acid (GABAA) receptors and mitogen-activated protein kinase/extracellular sig-nal-regulated protein kinase (MAPK/ERK) activity were detected by Western blotting. Results: Pretreatment with celecoxib showed protection against pilocarpine-induced seizures. Celecoxib prevented microglia activation in the hilus and inhibited the abnormal neurogenesis and astrogliosis in the hippocampus by inhibiting MAPK/ERK activity and c-Fos transcription. Celecoxib also up-regulated the expression of GABAA receptors. NS-398 (N-2-cyclohexyloxy-4-nitrophenyl-methanesuifonamide), another COX-2 inhibitor, enhanced the frequency and decay time of mIPSCs. Conclusion: The COX-2 inhibitor celecoxib decreased neuronal excitability and prevented epileptogenesis in pilocarpine-induced status epilepticus rats. Celecoxib regulates synaptic reorganization by inhibiting astrogliosis and ectopic neurogenesis by attenuating MAPK/ERK signal activity, mediated by a GABAergic mechanism.

  9. Reorganization of the injured brain: Implications for studies of the neural substrate of cognition

    Directory of Open Access Journals (Sweden)

    Jesper eMogensen

    2011-01-01

    Full Text Available In the search for a neural substrate of cognitive processes, a frequently utilized method is the scrutiny of posttraumatic symptoms exhibited by individuals suffering focal injury to the brain. For instance, the presence or absence of conscious awareness within a particular domain may, combined with knowledge of which regions of the brain have been injured, provide important data in the search for neural correlates of consciousness. Like all studies addressing the consequences of brain injury, however, such research has to face the fact that in most cases, posttraumatic impairments are accompanied by a functional recovery during which symptoms are reduced or eliminated. The apparent contradiction between localization and recovery, respectively, of functions constitutes a problem to almost all aspects of cognitive neuroscience. Several lines of investigation indicate that although the brain remains highly plastic throughout life, the posttraumatic plasticity does not recreate a copy of the neural mechanisms lost to injury. Instead, the uninjured parts of the brain are functionally reorganized in a manner which – in spite of not recreating the basic information processing lost to injury – is able to allow a more or less complete return of the surface phenomena (including manifestations of consciousness originally impaired by the trauma. A novel model (the REF-model of these processes is presented – and some of its implications discussed relative to studies of the neural substrates of cognition and consciousness.

  10. Ice stream reorganization and glacial retreat on the northwest Greenland shelf

    Science.gov (United States)

    Newton, A. M. W.; Knutz, P. C.; Huuse, M.; Gannon, P.; Brocklehurst, S. H.; Clausen, O. R.; Gong, Y.

    2017-08-01

    Understanding conditions at the grounding-line of marine-based ice sheets is essential for understanding ice sheet evolution. Offshore northwest Greenland, knowledge of the Last Glacial Maximum (LGM) ice sheet extent in Melville Bugt was previously based on sparse geological evidence. This study uses multibeam bathymetry, combined with 2-D and 3-D seismic reflection data, to present a detailed landform record from Melville Bugt. Seabed landforms include mega-scale glacial lineations, grounding-zone wedges, iceberg scours, and a lateral shear margin moraine, formed during the last glacial cycle. The geomorphology indicates that the LGM ice sheet reached the shelf edge before undergoing flow reorganization. After retreat of 80 km across the outer shelf, the margin stabilized in a mid-shelf position, possibly during the Younger Dryas (12.9-11.7 ka). The ice sheet then decoupled from the seafloor and retreated to a coast-proximal position. This landform record provides an important constraint on deglaciation history offshore northwest Greenland.

  11. SCFSlimb ubiquitin ligase suppresses condensin II–mediated nuclear reorganization by degrading Cap-H2

    Science.gov (United States)

    Buster, Daniel W.; Daniel, Scott G.; Nguyen, Huy Q.; Windler, Sarah L.; Skwarek, Lara C.; Peterson, Maureen; Roberts, Meredith; Meserve, Joy H.; Hartl, Tom; Klebba, Joseph E.; Bilder, David; Bosco, Giovanni

    2013-01-01

    Condensin complexes play vital roles in chromosome condensation during mitosis and meiosis. Condensin II uniquely localizes to chromatin throughout the cell cycle and, in addition to its mitotic duties, modulates chromosome organization and gene expression during interphase. Mitotic condensin activity is regulated by phosphorylation, but mechanisms that regulate condensin II during interphase are unclear. Here, we report that condensin II is inactivated when its subunit Cap-H2 is targeted for degradation by the SCFSlimb ubiquitin ligase complex and that disruption of this process dramatically changed interphase chromatin organization. Inhibition of SCFSlimb function reorganized interphase chromosomes into dense, compact domains and disrupted homologue pairing in both cultured Drosophila cells and in vivo, but these effects were rescued by condensin II inactivation. Furthermore, Cap-H2 stabilization distorted nuclear envelopes and dispersed Cid/CENP-A on interphase chromosomes. Therefore, SCFSlimb-mediated down-regulation of condensin II is required to maintain proper organization and morphology of the interphase nucleus. PMID:23530065

  12. Management of change in the nuclear industry - Evidence from maintenance reorganizations

    Energy Technology Data Exchange (ETDEWEB)

    Reiman, T.; Oedewald, P. [VTT Industrial Systems (Finland); Rollenhagen, C.; Kahlbom, U. [Maelardalen Univ. (Sweden)

    2006-03-15

    The nuclear industry and especially the maintenance activities have been under various restructuring initiatives in addition to continuous incremental change due to e.g. new technologies, ageing plants, deregulation and the change of generation. These changes have been experienced as causing stress and uncertainty among the workers. Also, changes have lead to e.g. lowered sense of control, goal unclarity and lowered sense of personal responsibility over one's work. Organizational changes clearly are issues that have potential effects on safety. Both positive and negative cases on safety effects of organizational changes exist, and various accidents have been pinpointed to organizational changes in the company. In this report the challenges of management of change at nuclear power plants are considered mainly from organizational culture -perspective. The cultural perspective taken in this paper strives to combine technical approaches to human resources approaches. The report focuses on evidence gathered from studies made at Nordic NPP maintenance units, but the results and models depicted in the report are of general relevance in the nuclear industry. The report is based on four case studies of reorganizing in NPP maintenance units and on a literature review of change management at various other safety critical organizations. The report presents a framework for considering organizational changes and their safety consequences. (au)

  13. Electrolyte-induced reorganization of SDS self-assembly on graphene: a molecular simulation study.

    Science.gov (United States)

    Liu, Shuyan; Wu, Bin; Yang, Xiaoning

    2014-04-23

    A molecular dynamics simulation was conducted to study the structure and morphology of sodium dodecyl sulfate (SDS) surfactants adsorbed on a nanoscale graphene nanostructure in the presence of an electrolyte. The self-assembly structure can be reorganized by the electrolyte-induced effect. An increase in the ionic strength of the added electrolyte can enhance the stretching of adsorbed surfactants toward the bulk aqueous phase and make headgroups assemble densely, leading to a more compact structure of the SDS/graphene composite. The change in the self-assembly structure is attributed to the accumulation/condensation of electrolyte cations near the surfactant aggregate, consequently screening the electrostatic repulsion between charged headgroups. The role of the electrolyte revealed here provides direct microscopic evidence or an explanation of the reported experiments in the electrolyte tuning of the interfacial structure of a surfactant aggregate on the surface of carbon nanoparticles. Additionally, the buoyant density of the SDS/graphene assembly has been computed. With an increase in the ionic strength of the electrolyte, the buoyant density of the SDS/graphene composite rises. The interfacial accumulation of electrolytes provides an important contribution to the density enhancement. The study will be valuable for the dispersion and application of graphene nanomaterials.

  14. Structural Reorganization and Fibrinogen Adsorption Behaviors on the Polyrotaxane Surfaces Investigated by Sum Frequency Generation Spectroscopy.

    Science.gov (United States)

    Ge, Aimin; Seo, Ji-Hun; Qiao, Lin; Yui, Nobuhiko; Ye, Shen

    2015-10-14

    Polyrotaxanes, such as supramolecular assemblies with methylated α-cyclodextrins (α-CDs) as host molecules noncovalently threaded on the linear polymer backbone, are promising materials for biomedical applications because they allow adsorbed proteins possessing a high surface flexibility as well as control of the cellular morphology and adhesion. To provide a general design principle for biomedical materials, we examined the surface reorganization behaviors and adsorption conformations of fibrinogen on the polyrotaxane surfaces with comparison to several random copolymers by sum frequency generation (SFG) vibrational spectroscopy. We showed that the polyrotaxane (OMe-PRX-PMB) with methylated α-CDs as the host molecule exhibited unique surface structures in an aqueous environment. The hydrophobic interaction between the methoxy groups of the methylated α-CD molecules and methyl groups of the n-butyl methacrylate (BMA) side chains may dominate the surface restructuring behavior of the OMe-PRX-PMB. The orientation analysis revealed that the orientation of the fibrinogen adsorbed on the OMe-PRX-PMB surface is close to a single distribution, which is different from the adsorption behaviors of fibrinogen on other polyrotaxane or random copolymer surfaces.

  15. CRITICAL ANALYSIS OF THE MECHANOSTAT THEORY PART I. REORGANIZATION MECHANISMS OF SKELETAL ARCHITECTURE

    Directory of Open Access Journals (Sweden)

    A. S. Avrunin

    2012-01-01

    Full Text Available The paper contains a critical analysis of the mechanostat theory. It is shown that for continuous modeling and osteoklastic-and-osteoblastic remodeling is not providing the necessary safety margin of skeletal structures and reduce risk of fractures. It is established that at each level of the hierarchical organization of a skeleton there are also other mechanisms of its reorganization. The functioning of this system is controlled by mechanisms of osteocytes and purposefully provides two effects: the first -preservation of bone structures deformability according to demanded productivity of convective fluid movement mechanism of a lacunary-tubular system, second - the optimization of the cross-section of the cavities of a lacunary-tubular system, respectively, the required level of throughput for the flow of fluid. As a result, the parameters of mechanical-metabolic environment surrounding the osteocytes are stored in the homeostatic limits, which increases cell viability, and hence bone and skeleton as a whole. However, this is often at the expense of the strength properties of bone structures.

  16. Cerebral reorganization as a function of linguistic recovery in children: An fMRI study.

    Science.gov (United States)

    Elkana, Odelia; Frost, Ram; Kramer, Uri; Ben-Bashat, Dafna; Hendler, Talma; Schmidt, David; Schweiger, Avraham

    2011-02-01

    Characterizing and mapping the relationship between neuronal reorganization and functional recovery are essential to the understanding of cerebral plasticity and the dynamic processes which occur following brain damage. The neuronal mechanisms underlying linguistic recovery following left hemisphere (LH) lesions are still unknown. Using functional magnetic resonance imaging (fMRI), we investigated whether the extent of brain lateralization of linguistic functioning in specific regions of interest (ROIs) is correlated with the level of linguistic performance following recovery from acquired childhood aphasia. The study focused on a rare group of children in whom lesions occurred after normal language acquisition, but prior to complete maturation of the brain. During fMRI scanning, rhyming, comprehension and verb generation activation tasks were monitored. The imaging data were evaluated with reference to linguistic performance measured behaviorally during imaging, as well as outside the scanner. Compared with normal controls, we found greater right hemisphere (RH) lateralization in patients. However, correlations with linguistic performance showed that increased proficiency in linguistic tasks was associated with greater lateralization to the LH. These results were replicated in a longitudinal case study of a patient scanned twice, 3 years apart. Additional improvement in linguistic performance of the patient was accompanied by increasing lateralization to the LH in the anterior language region. This, however, was the result of a decreased involvement of the RH. These findings suggest that recovery is a dynamic, ongoing process, which may last for years after onset. The role of each hemisphere in the recovery process may continuously change within the chronic stage.

  17. Electrically induced reorganization phenomena of liquid metal film printed on biological skin

    Science.gov (United States)

    Guo, Cangran; Yi, Liting; Yu, Yang; Liu, Jing

    2016-12-01

    Liquid metal has been demonstrated to be directly printable on biological skin as physiological measurement elements. However, many fundamental issues remained unclear so far. Here, we disclosed an intriguing phenomenon of electrically induced reorganization of liquid metal film. According to the experiments, when applying an external electric field to liquid metal films which were spray printed on biological skin, it would induce unexpected transformations of the liquid metals among different morphologies and configurations. These include shape shift from a large liquid metal film into a tiny sphere and contraction of liquid metal pool into spherical one. For comprehensively understanding the issues, the impacts of the size, voltage, orientations of the liquid metal electrodes, etc., were clarified. Further, effects of various substrates such as in vitro skin and in vivo skin affecting the liquid metal transformations were experimentally investigated. Compared to the intact tissues, the contraction magnitude of the liquid metal electrode appears weaker on in vivo skin of nude mice under the same electric field. The mechanisms lying behind such phenomena were interpreted through theoretical modeling. Lastly, typical applications of applying the current effect into practical elements such as electrical gating devices were also illustrated as an example. The present findings have both fundamental and practical values, which would help design future technical strategies in fabricating electronically controlled liquid metal electronics on skin.

  18. River piracy and drainage basin reorganization led by climate-driven glacier retreat

    Science.gov (United States)

    Shugar, Daniel H.; Clague, John J.; Best, James L.; Schoof, Christian; Willis, Michael J.; Copland, Luke; Roe, Gerard H.

    2017-04-01

    River piracy--the diversion of the headwaters of one stream into another one--can dramatically change the routing of water and sediment, with a profound effect on landscape evolution. Stream piracy has been investigated in glacial environments, but so far it has mainly been studied over Quaternary or longer timescales. Here we document how retreat of Kaskawulsh Glacier--one of Canada's largest glaciers--abruptly and radically altered the regional drainage pattern in spring 2016. We use a combination of hydrological measurements and drone-generated digital elevation models to show that in late May 2016, meltwater from the glacier was re-routed from discharge in a northward direction into the Bering Sea, to southward into the Pacific Ocean. Based on satellite image analysis and a signal-to-noise ratio as a metric of glacier retreat, we conclude that this instance of river piracy was due to post-industrial climate change. Rapid regional drainage reorganizations of this type can have profound downstream impacts on ecosystems, sediment and carbon budgets, and downstream communities that rely on a stable and sustained discharge. We suggest that the planforms of Slims and Kaskawulsh rivers will adjust in response to altered flows, and the future Kaskawulsh watershed will extend into the now-abandoned headwaters of Slims River and eventually capture the Kluane Lake drainage.

  19. Reorganizing therapy: changing the clinical approach to upper limb recovery post-stroke.

    Science.gov (United States)

    Hubbard, Isobel J; Carey, Leeanne M; Budd, Timothy W; Parsons, Mark W

    2015-03-01

    Stroke is the leading cause of adult disability, and as a consequence, most therapists will provide health care to patients with stroke during their professional careers. An increasing number of studies are investigating the association between upper limb recovery and changes in brain activation patterns following stroke. In this review, we explore the translational implications of this research for health professionals working in stroke recovery. We argue that in light of the most recent evidence, therapists should consider how best to take full advantage of the brain's natural ability to reorganize, when prescribing and applying interventions to those with a stroke-affected upper limb. The authors propose that stroke is a brain-based problem that needs a brain-based solution. This review addresses two topics, anticipating recovery and maximizing recovery. It proposes five practice-ready recommendations that are based on the evidence reviewed. The over-riding aim of this review and discussion is to challenge therapists to reconsider the health care they prescribe and apply to people with a stroke-affected upper limb.

  20. Reorganizing Neural Network System for Two Spirals and Linear Low-Density Polyethylene Copolymer Problems

    Directory of Open Access Journals (Sweden)

    G. M. Behery

    2009-01-01

    Full Text Available This paper presents an automatic system of neural networks (NNs that has the ability to simulate and predict many of applied problems. The system architectures are automatically reorganized and the experimental process starts again, if the required performance is not reached. This processing is continued until the performance obtained. This system is first applied and tested on the two spiral problem; it shows that excellent generalization performance obtained by classifying all points of the two-spirals correctly. After that, it is applied and tested on the shear stress and the pressure drop problem across the short orifice die as a function of shear rate at different mean pressures for linear low-density polyethylene copolymer (LLDPE at 190∘C. The system shows a better agreement with an experimental data of the two cases: shear stress and pressure drop. The proposed system has been also designed to simulate other distributions not presented in the training set (predicted and matched them effectively.

  1. Alkyl ether lipids, ion channels and lipid raft reorganization in cancer therapy.

    Science.gov (United States)

    Jaffrès, Paul-Alain; Gajate, Consuelo; Bouchet, Ana Maria; Couthon-Gourvès, Hélène; Chantôme, Aurélie; Potier-Cartereau, Marie; Besson, Pierre; Bougnoux, Philippe; Mollinedo, Faustino; Vandier, Christophe

    2016-09-01

    Synthetic alkyl lipids, such as the ether lipids edelfosine (1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine) and ohmline (1-O-hexadecyl-2-O-methyl-rac-glycero-3-β-lactose), are forming a class of antitumor agents that target cell membranes to induce apoptosis and to decrease cell migration/invasion, leading to the inhibition of tumor and metastasis development. In this review, we present the structure-activity relationship of edelfosine and ohmline, and we point out differences and similarities between these two amphiphilic compounds. We also discuss the mechanisms of action of these synthetic alkyl ether lipids (involving, among other structures and molecules, membrane domains, Fas/CD95 death receptor signaling, and ion channels), and highlight a key role for lipid rafts in the underlying process. The reorganization of lipid raft membrane domains induced by these alkyl lipids affects the function of death receptors and ion channels, thus leading to apoptosis and/or inhibition of cancer cell migration. The possible therapeutic use of these alkyl lipids and the clinical perspectives for these lipids in prevention or/and treatment of tumor development and metastasis are also discussed.

  2. F-actin reorganization upon de- and rehydration in the aeroterrestrial green alga Klebsormidium crenulatum.

    Science.gov (United States)

    Blaas, Kathrin; Holzinger, Andreas

    2017-07-01

    Filamentous actin (F-actin) is a dynamic network involved in many cellular processes like cell division and cytoplasmic streaming. While many studies have addressed the involvement of F-actin in different cellular processes in cultured cells, little is known on the reactions to environmental stress scenarios, where this system might have essential regulatory functions. We investigated here the de- and rehydration kinetics of breakdown and reassembly of F-actin in the streptophyte green alga Klebsormidium crenulatum. Measurements of the chlorophyll fluorescence (effective quantum yield of photosystem II [ΔF/Fm']) via pulse amplitude modulation were performed as a measure for dehydration induced shut down of physiological activity, which ceased after 141±15min at ∼84% RH. We hypothesized that there is a link between this physiological parameter and the status of the F-actin system. Indeed, 20min of dehydration (ΔF/Fm'=0) leads to a breakdown of the fine cortical F-actin network as visualized by Atto 488 phalloidin staining, and dot-like structures remained. Already 10min after rehydration a beginning reassembly of F-actin is observed, after 25min the F-actin network appeared similar to untreated controls, indicating a full recovery. These results demonstrate the fast kinetics of F-actin dis- and reassembly likely contributing to cellular reorganization upon rehydration. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  3. Abscisic acid induces ectopic outgrowth in epidermal cells through cortical microtubule reorganization in Arabidopsis thaliana

    Science.gov (United States)

    Takatani, Shogo; Hirayama, Takashi; Hashimoto, Takashi; Takahashi, Taku; Motose, Hiroyasu

    2015-01-01

    Abscisic acid (ABA) regulates seed maturation, germination and various stress responses in plants. The roles of ABA in cellular growth and morphogenesis, however, remain to be explored. Here, we report that ABA induces the ectopic outgrowth of epidermal cells in Arabidopsis thaliana. Seedlings of A. thaliana germinated and grown in the presence of ABA developed ectopic protrusions in the epidermal cells of hypocotyls, petioles and cotyledons. One protrusion was formed in the middle of each epidermal cell. In the hypocotyl epidermis, two types of cell files are arranged alternately into non-stoma cell files and stoma cell files, ectopic protrusions being restricted to the non-stoma cell files. This suggests the presence of a difference in the degree of sensitivity to ABA or in the capacity of cells to form protrusions between the two cell files. The ectopic outgrowth was suppressed in ABA insensitive mutants, whereas it was enhanced in ABA hypersensitive mutants. Interestingly, ABA-induced ectopic outgrowth was also suppressed in mutants in which microtubule organization was compromised. Furthermore, cortical microtubules were disorganized and depolymerized by the ABA treatment. These results suggest that ABA signaling induces ectopic outgrowth in epidermal cells through microtubule reorganization. PMID:26068445

  4. Reorganization energy, activation energy, and mechanism of hole transfer process in DNA: a theoretical study.

    Science.gov (United States)

    Khan, Arshad

    2008-02-21

    The density functional calculations with aug-cc-pVDZ basis sets on cationic guanine-cytosine (GC(+)) and adenine-thymine (AT(+)) base pairs suggest that the cationic charge is almost entirely localized on the G and A units with significant changes in the N-H and N...O distances around the H-bonded area. While the calculated intramolecular reorganization energy (lambda(v)) for a GC base pair (0.75 eV) is remarkably larger than that for an isolated G base (0.49 eV), for the AT base pairs these values (0.44 and 0.40 eV) are almost the same. The gas phase activation energies (E(a)) for GC(+)GC-->GCGC(+), AT(+)AT-->ATAT(+), and GC(+)AT-->GCAT(+) hole transfer processes are 0.19, 0.11, and 0.73 eV with rate constants of 1.69 x 10(11), 3.15 x 10(11), and 4.61(0.168) s(-1), respectively, at 298 K. An alternative mechanism of hole transfer has been proposed on the basis of energy barriers.

  5. Cortex-M0处理器初探%Cortex-M0 Processor:An Initial Survey

    Institute of Scientific and Technical Information of China (English)

    范云龙; 方安平; 李宁

    2010-01-01

    介绍Cortex-M0处理器的特点;详细分析Cortex-M0处理器的编程模型、存储模型、异常处理和功耗管理,并将Cortex-M0与Cortex-M3和基于8/16位架构的处理器作了对比分析;最后简要介绍Cortex-M0处理器的相关开发工具.

  6. Compensatory plasticity and cross-modal reorganization following early visual deprivation.

    Science.gov (United States)

    Kupers, Ron; Ptito, Maurice

    2014-04-01

    For human and non-human primates, vision is one of the most privileged sensory channels used to interact with the environment. The importance of vision is strongly embedded in the organization of the primate brain as about one third of its cortical surface is involved in visual functions. It is therefore not surprising that the absence of vision from birth, or the loss of vision later in life, has huge consequences, both anatomically and functionally. Studies in animals and humans, conducted over the past few decades, have demonstrated that the absence of vision causes massive structural changes that take place not only in the visually deprived cortex but also in other brain areas. These studies have further shown that the visually deprived cortex becomes responsive to a wide variety of non-visual sensory inputs. Recent studies even showed a role of the visually deprived cortex in cognitive processes. At the behavioral level, increases in acuity for auditory and tactile processes have been reported. The study of the congenitally blind brain also offers a unique model to gain better insights into the functioning of the normal sighted brain and to understand to what extent visual experience is necessary for the brain to develop its functional architecture. Finally, the study of the blind brain allows us to investigate how consciousness develops in the absence of vision. How does the brain of someone who has never had any visual perception form an image of the external world? In this paper, we discuss recent findings from animal studies as well as from behavioural and functional brain imaging studies in sighted and blind individuals that address these questions.

  7. Associative Encoding in Anterior Piriform Cortex versus Orbitofrontal Cortex during Odor Discrimination and Reversal Learning

    Science.gov (United States)

    Roesch, Matthew R.; Stalnaker, Thomas A.; Schoenbaum, Geoffrey

    2008-01-01

    Recent proposals have conceptualized piriform cortex as an association cortex, capable of integrating incoming olfactory information with descending input from higher order associative regions such as orbitofrontal cortex (OFC). If true, encoding in piriform cortex should reflect associative features prominent in these areas during associative learning involving olfactory cues. To test this hypothesis, we recorded from neurons in OFC and anatomically related parts of the anterior piriform cortex (APC) in rats, learning and reversing novel odor discriminations. Findings in OFC were similar to what we have reported previously, with nearly all the cue-selective neurons exhibiting substantial plasticity during learning and reversal. Also, many of the cue-selective neurons were originally responsive in anticipation of the outcomes early in learning, thereby providing a single-unit representation of the cue-outcome associations. Some of these features were also evident in firing activity in APC, including some plasticity across learning and reversal. However, APC neurons failed to reverse cue selectivity when the associated outcome was changed, and the cue-selective population did not include neurons that were active prior to outcome delivery. Thus, although representations in APC are substantially more associative than expected in a purely sensory region, they do appear to be somewhat more constrained by the sensory features of the odor cues than representations in downstream areas of OFC. PMID:16699083

  8. Directed assembly of gold nanowires on silicon via reorganization and simultaneous fusion of randomly distributed gold nanoparticles.

    Science.gov (United States)

    Reinhardt, Hendrik M; Bücker, Kerstin; Hampp, Norbert A

    2015-05-04

    Laser-induced reorganization and simultaneous fusion of nanoparticles is introduced as a versatile concept for pattern formation on surfaces. The process takes advantage of a phenomenon called laser-induced periodic surface structures (LIPSS) which originates from periodically alternating photonic fringe patterns in the near-field of solids. Associated photonic fringe patterns are shown to reorganize randomly distributed gold nanoparticles on a silicon wafer into periodic gold nanostructures. Concomitant melting due to optical heating facilitates the formation of continuous structures such as periodic gold nanowire arrays. Generated patterns can be converted into secondary structures using directed assembly or self-organization. This includes for example the rotation of gold nanowire arrays by arbitrary angles or their fragmentation into arrays of aligned gold nanoparticles.

  9. Neuroplastic Sensorimotor Resting State Network Reorganization in Children With Hemiplegic Cerebral Palsy Treated With Constraint-Induced Movement Therapy.

    Science.gov (United States)

    Manning, Kathryn Y; Menon, Ravi S; Gorter, Jan Willem; Mesterman, Ronit; Campbell, Craig; Switzer, Lauren; Fehlings, Darcy

    2016-02-01

    Using resting state functional magnetic resonance imaging (MRI), we aim to understand the neurologic basis of improved function in children with hemiplegic cerebral palsy treated with constraint-induced movement therapy. Eleven children including 4 untreated comparison subjects diagnosed with hemiplegic cerebral palsy were recruited from 3 clinical centers. MRI and clinical data were gathered at baseline and 1 month for both groups, and 6 months later for the case group only. After constraint therapy, the sensorimotor resting state network became more bilateral, with balanced contributions from each hemisphere, which was sustained 6 months later. Sensorimotor resting state network reorganization after therapy was correlated with a change in the Quality of Upper Extremity Skills Test score at 1 month (r = 0.79, P = .06), and Canadian Occupational Performance Measure scores at 6 months (r = 0.82, P = .05). This clinically correlated resting state network reorganization provides further evidence of the neuroplastic mechanisms underlying constraint-induced movement therapy.

  10. Cortical Reorganization in Patients Recovered from Bell's Palsy: An Orofacial and Finger Movements Task-State fMRI Study

    Science.gov (United States)

    Lee, Jaeyoun; Yuan, Aihong; Wu, Hongli; Wang, Anqin; Xue, Qiuju; Wang, Tao; Wang, Linying; Gao, Ting

    2016-01-01

    Objective. To explore cortical reorganization of patients recovered from Bell's palsy (BP) by task-state functional magnetic resonance imaging (fMRI) during finger and orofacial movements and provide more evidence for acupuncture clinical treatment of BP. Methods. We collected 17 BP patients with complete clinical recovery (BP group) and 20 healthy volunteers (control group) accepted the task-state fMRI scans with lip pursing movements and finger movements, respectively. Results. It was found that there were significant differences of brain functional status between the two groups. Conclusions. The results showed that there was cortical reorganization in the brain of patients recovered from BP after acupuncture treatment, which also suggested the relationship between the hand motor areas and facial motor areas of BP patients. PMID:28116170

  11. Efficient energy transfer in light-harvesting systems, I: optimal temperature, reorganization energy, and spatial-temporal correlations

    CERN Document Server

    Wu, Jianlan; Shen, Young; Cao, Jianshu; Silbey, Robert J

    2010-01-01

    Understanding the mechanisms of efficient and robust energy transfer in light-harvesting systems provides new insights for the optimal design of artificial systems. In this paper, we use the Fenna-Matthews-Olson (FMO) protein complex and phycocyanin 645 (PC 645) to explore the general dependence on physical parameters that help maximize the efficiency and maintain its stability. With the Haken-Strobl model, the maximal energy transfer efficiency (ETE) is achieved under an intermediate optimal value of dephasing rate. Guided by the insight, we use the generalized Bloch-Redfield (GBR) equation approach to correctly describe dissipative exciton dynamics and find that maximal ETE can be achieved under various physical conditions, including temperature, reorganization energy, and spatial-temporal correlations in noise. We also identify regimes of reorganization energy where the ETE changes monotonically with temperature or spatial correlation and therefore cannot be optimized with respect to these two variables.

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

    Science.gov (United States)

    van Lamsweerde, Amanda E; Johnson, Jeffrey S

    2017-07-01

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

  13. Layer-specific diffusion weighted imaging in human primary visual cortex in vitro.

    Science.gov (United States)

    Kleinnijenhuis, Michiel; Zerbi, Valerio; Küsters, Benno; Slump, Cornelis H; Barth, Markus; van Cappellen van Walsum, Anne-Marie

    2013-10-01

    One of the most prominent characteristics of the human neocortex is its laminated structure. The first person to observe this was Francesco Gennari in the second half the 18th century: in the middle of the depth of primary visual cortex, myelinated fibres are so abundant that he could observe them with bare eyes as a white line. Because of its saliency, the stria of Gennari has a rich history in cyto- and myeloarchitectural research as well as in magnetic resonance (MR) microscopy. In the present paper we show for the first time the layered structure of the human neocortex with ex vivo diffusion weighted imaging (DWI). To achieve the necessary spatial and angular resolution, primary visual cortex samples were scanned on an 11.7 T small-animal MR system to characterize the diffusion properties of the cortical laminae and the stria of Gennari in particular. The results demonstrated that fractional anisotropy varied over cortical depth, showing reduced anisotropy in the stria of Gennari, the inner band of Baillarger and the deepest layer of the cortex. Orientation density functions showed multiple components in the stria of Gennari and deeper layers of the cortex. Potential applications of layer-specific diffusion imaging include characterization of clinical abnormalities, cortical mapping and (intra)cortical tractography. We conclude that future high-resolution in vivo cortical DWI investigations should take into account the layer-specificity of the diffusion properties.

  14. Poor Tolerance of Motor Cortex rTMS in Chronic Migraine

    Science.gov (United States)

    Teo, Wei-Peng; Kannan, Aravinda; Loh, Pei-Kee; Chew, Effie; Sharma, Vijay Kumar

    2014-01-01

    Background: Two small studies had evaluated the efficacy of rTMS in migraine. One tested high frequency rTMS over the dorsolateral prefrontal cortex while the other evaluated 1 Hz rTMS over the vertex. Aim: To test the feasibility of 10 Hz rTMS of motor cortex as an adjunctive therapy in patients with chronic migraine Materials and Methods: We randomized (2:1 ratio) chronic migraine patients on medical preventive treatment to receive either rTMS or sham therapy for 10 sessions. rTMS (80% resting motor threshold, 10Hz, 20 trains, 5 secs/train, inter-train interval 1 min, total 1000 stimuli/session) was applied over the right motor cortex. Result: Nine patients were randomized. Six received rTMS and three had sham therapy. Three patients in the rTMS arm withdrew from the study due to increased headache frequency and discomfort from the treatment. The remaining six cases (3 rTMS, 3 sham) completed the study. The study was prematurely stopped due to the significant worsening of headache from rTMS. No significant differences in outcome measures were found between real and sham rTMS. Conclusion: Although the study was terminated prematurely, the high dropout rate (50%) due to worsening headaches suggested that rTMS over the motor cortex is poorly tolerated in chronic migraine. PMID:25386478

  15. Impaired executive function following ischemic stroke in the rat medial prefrontal cortex.

    Science.gov (United States)

    Cordova, Chris A; Jackson, Danielle; Langdon, Kristopher D; Hewlett, Krista A; Corbett, Dale

    2014-01-01

    Small (lacunar) infarcts frequently arise in frontal and midline thalamic regions in the absence of major stroke. Damage to these areas often leads to impairment of executive function likely as a result of interrupting connections of the prefrontal cortex. Thus, patients experience frontal-like symptoms such as impaired ability to shift ongoing behavior and attention. In contrast, executive dysfunction has not been demonstrated in rodent models of stroke, thereby limiting the development of potential therapies for human executive dysfunction. Male Sprague-Dawley rats (n=40) underwent either sham surgery or bilateral endothelin-1 injections in the mediodorsal nucleus of the thalamus or in the medial prefrontal cortex. Executive function was assessed using a rodent attention set shifting test that requires animals to shift attention to stimuli in different stimulus dimensions. Medial prefrontal cortex ischemia impaired attention shift performance between different stimulus dimensions while sparing stimulus discrimination and attention shifts within a stimulus dimension, indicating a selective attention set-shift deficit. Rats with mediodorsal thalamic lacunar damage did not exhibit a cognitive impairment relative to sham controls. The selective attention set shift impairment observed in this study is consistent with clinical data demonstrating selective executive disorders following stroke within specific sub-regions of frontal cortex. These data contribute to the development and validation of a preclinical animal model of executive dysfunction, that can be employed to identify potential therapies for ameliorating cognitive deficits following stroke.

  16. State- and trait-related alterations of motor cortex excitability in tinnitus patients.

    Directory of Open Access Journals (Sweden)

    Martin Schecklmann

    Full Text Available Chronic tinnitus is a brain network disorder with involvement of auditory and non-auditory areas. Repetitive transcranial magnetic stimulation (rTMS over the temporal cortex has been investigated for the treatment of tinnitus. Several small studies suggest that motor cortex excitability is altered in people with tinnitus. We retrospectively analysed data from 231 patients with chronic tinnitus and 120 healthy controls by pooling data from different studies. Variables of interest were resting motor threshold (RMT, short-interval intra-cortical inhibition (SICI, intra-cortical facilitation (ICF, and cortical silent period (CSP. 118 patients were tested twice - before and after ten rTMS treatment sessions over the left temporal cortex. In tinnitus patients SICI and ICF were increased and CSP was shortened as compared to healthy controls. There was no group difference in RMT. Treatment related amelioration of tinnitus symptoms were correlated with normalisations in SICI. These findings confirm earlier studies of abnormal motor cortex excitability in tinnitus patients. Moreover our longitudinal data suggest that altered SICI may reflect a state parameter, whereas CSP and ICF may rather mirror a trait-like predisposing factor of tinnitus. These findings are new and innovative as they enlarge the knowledge about basic physiologic and neuroplastic processes in tinnitus.

  17. Segregation of vowels and consonants in human auditory cortex: Evidence for distributed hierarchical organization

    Directory of Open Access Journals (Sweden)

    Jonas eObleser

    2010-12-01

    Full Text Available The speech signal consists of a continuous stream of consonants and vowels, which must be de– and encoded in human auditory cortex to ensure the robust recognition and categorization of speech sounds. We used small-voxel functional magnetic resonance imaging (fMRI to study information encoded in local brain activation patterns elicited by consonant-vowel syllables, and by a control set of noise bursts.First, activation of anterior–lateral superior temporal cortex was seen when controlling for unspecific acoustic processing (syllables versus band-passed noises, in a classic subtraction-based design. Second, a classifier algorithm, which was trained and tested iteratively on data from all subjects to discriminate local brain activation patterns, yielded separations of cortical patches discriminative of vowel category versus patches discriminative of stop-consonant category across the entire superior temporal cortex, yet with regional differences in average classification accuracy. Overlap (voxels correctly classifying both speech sound categories was surprisingly sparse. Third, lending further plausibility to the results, classification of speech–noise differences was generally superior to speech–speech classifications, with the notable exception of a left anterior region, where speech–speech classification accuracies were significantly better.These data demonstrate that acoustic-phonetic features are encoded in complex yet sparsely overlapping local patterns of neural activity distributed hierarchically across different regions of the auditory cortex. The redundancy apparent in these multiple patterns may partly explain the robustness of phonemic representations.

  18. Evidence against a single coordinate system representation in the motor cortex.

    Science.gov (United States)

    Wu, Wei; Hatsopoulos, Nicholas

    2006-11-01

    Understanding the coordinate systems in which the motor cortical cells encode movement parameters such as direction is a fundamental yet unresolved issue. Although many studies have assumed that motor cortex encodes direction in an extrinsic, Cartesian (CA) coordinate system, other studies have provided evidence for encoding in intermediate coordinate systems such as a shoulder-centered (SC) or in a purely intrinsic, joint-angle-based (JA) coordinate frame. By simultaneously recording from multiple single units in primary motor cortex, we examined movement direction encoding under each of these three coordinate systems. We directly compared the degree of directional tuning invariance over multiple sub-regions in the workspace. We also compared the mutual information between neuronal firing rate and movement direction in the three systems. We observed a broad range of directional invariance in all three coordinate systems with no strong dominance of any single coordinate system. The mutual information analyses corroborated this observation. However, we found a small but significant bias toward the SC coordinate frame, which was also supported by population vector decoding. Similar results were found when we compared hand/torque force direction encoding in all three coordinate systems. These results suggest that the motor cortex employs a coordinate system that is yet to be discovered or perhaps that the motor cortex should not be viewed as a substrate for any coordinate system representation.

  19. Genomic loss of tumor suppressor miRNA-204 promotes cancer cell migration and invasion by activating AKT/mTOR/Rac1 signaling and actin reorganization.

    Directory of Open Access Journals (Sweden)

    J Saadi Imam

    Full Text Available Increasing evidence suggests that chromosomal regions containing microRNAs are functionally important in cancers. Here, we show that genomic loci encoding miR-204 are frequently lost in multiple cancers, including ovarian cancers, pediatric renal tumors, and breast cancers. MiR-204 shows drastically reduced expression in several cancers and acts as a potent tumor suppressor, inhibiting tumor metastasis in vivo when systemically delivered. We demonstrated that miR-204 exerts its function by targeting genes involved in tumorigenesis including brain-derived neurotrophic factor (BDNF, a neurotrophin family member which is known to promote tumor angiogenesis and invasiveness. Analysis of primary tumors shows that increased expression of BDNF or its receptor tropomyosin-related kinase B (TrkB parallel a markedly reduced expression of miR-204. Our results reveal that loss of miR-204 results in BDNF overexpression and subsequent activation of the small GTPase Rac1 and actin reorganization through the AKT/mTOR signaling pathway leading to cancer cell migration and invasion. These results suggest that microdeletion of genomic loci containing miR-204 is directly linked with the deregulation of key oncogenic pathways that provide crucial stimulus for tumor growth and metastasis. Our findings provide a strong rationale for manipulating miR-204 levels therapeutically to suppress tumor metastasis.

  20. 一类分组密码的S盒重组算法%S-boxes reorganization algorithm for a class of block ciphers

    Institute of Scientific and Technical Information of China (English)

    杨宏志; 韩文报

    2009-01-01

    S盒是许多分组密码唯一的非线性部件,它的密码强度决定了整个密码算法的安全强度.足够大的S盒是安全的,但为了便于实现,分组密码多采用若干小S盒拼凑.针对一类分组密码算法,通过将S盒与密钥相关联,给出了S盒重组算法,丰富了S盒的应用模式,有效提高了分组密码的安全强度.%S-boxes are the only nonlinear components in many block cipher algorithms, and they decide the security strength of the whole algorithm. Generally speaking, a big enough S-box is secure. However, for the convenience of implementation, several small S-boxes were combined. Concerning one class of block ciphers, an S-boxes reorganized algorithm was given, which enriched S-boxes application patterns and improved the security strength.