Sample records for occipital cortex loc

  1. Neurochemical Changes Within Human Early Blind Occipital Cortex

    PubMed Central

    Weaver, Kurt E.; Richards, Todd L.; Saenz, Melissa; Petropoulos, Helen; Fine, Ione

    2015-01-01

    Early blindness results in occipital cortex neurons responding to a wide range of auditory and tactile stimuli. These changes in tuning properties are accompanied by an extensive reorganization of occipital cortex that includes alterations in anatomical structure, neurochemical and metabolic pathways. Although it has been established in animal models that neurochemical pathways are heavily affected by early visual deprivation, the effects of blindness on these pathways in humans is still not well characterized. Here, using 1H magnetic resonance spectroscopy in nine early blind and normally sighted subjects, we find that early blindness is associated with higher levels of creatine, choline and myo-Inositol and indications of lower levels of GABA within occipital cortex. These results suggest that the cross-modal responses associated with early blindness may, at least in part, be driven by changes within occipital biochemical pathways. PMID:23954804

  2. Occipital Cortex of Blind Individuals Is Functionally Coupled with Executive Control Areas of Frontal Cortex.

    PubMed

    Deen, Ben; Saxe, Rebecca; Bedny, Marina

    2015-08-01

    In congenital blindness, the occipital cortex responds to a range of nonvisual inputs, including tactile, auditory, and linguistic stimuli. Are these changes in functional responses to stimuli accompanied by altered interactions with nonvisual functional networks? To answer this question, we introduce a data-driven method that searches across cortex for functional connectivity differences across groups. Replicating prior work, we find increased fronto-occipital functional connectivity in congenitally blind relative to blindfolded sighted participants. We demonstrate that this heightened connectivity extends over most of occipital cortex but is specific to a subset of regions in the inferior, dorsal, and medial frontal lobe. To assess the functional profile of these frontal areas, we used an n-back working memory task and a sentence comprehension task. We find that, among prefrontal areas with overconnectivity to occipital cortex, one left inferior frontal region responds to language over music. By contrast, the majority of these regions responded to working memory load but not language. These results suggest that in blindness occipital cortex interacts more with working memory systems and raise new questions about the function and mechanism of occipital plasticity. PMID:25803598

  3. Two retinotopic visual areas in human lateral occipital cortex

    PubMed Central

    Larsson, Jonas; Heeger, David J

    2007-01-01

    We describe two visual field maps, LO1 and LO2, in human lateral occipital cortex between dorsal V3 and V5/MT+. Each map contained a topographic representation of the contralateral visual hemifield. The eccentricity representations were shared with V1/V2/V3. The polar angle representation in LO1 extended from the lower vertical meridian (at the boundary with dorsal V3) through the horizontal to the upper vertical meridian (at the boundary with LO2). The polar angle representation in LO2 was the mirror-reversal of that in LO1. LO1 and LO2 overlapped with the posterior part of the object-selective lateral occipital complex and the kinetic occipital region (KO). The retinotopy and functional properties of LO1 and LO2 suggest that they correspond to two new human visual areas, which lack exact homologues in macaque visual cortex. The topography, stimulus selectivity and anatomical location of LO1 and LO2 indicate that they integrate shape information from multiple visual submodalities in retinotopic coordinates. PMID:17182764

  4. Stereoscopic Vision in the Absence of the Lateral Occipital Cortex

    PubMed Central

    Read, Jenny C. A.; Phillipson, Graeme P.; Serrano-Pedraza, Ignacio; Milner, A. David; Parker, Andrew J.

    2010-01-01

    Both dorsal and ventral cortical visual streams contain neurons sensitive to binocular disparities, but the two streams may underlie different aspects of stereoscopic vision. Here we investigate stereopsis in the neurological patient D.F., whose ventral stream, specifically lateral occipital cortex, has been damaged bilaterally, causing profound visual form agnosia. Despite her severe damage to cortical visual areas, we report that DF's stereo vision is strikingly unimpaired. She is better than many control observers at using binocular disparity to judge whether an isolated object appears near or far, and to resolve ambiguous structure-from-motion. DF is, however, poor at using relative disparity between features at different locations across the visual field. This may stem from a difficulty in identifying the surface boundaries where relative disparity is available. We suggest that the ventral processing stream may play a critical role in enabling healthy observers to extract fine depth information from relative disparities within one surface or between surfaces located in different parts of the visual field. PMID:20830303

  5. Mapping hV4 and ventral occipital cortex: The venous eclipse

    E-print Network

    Wandell, Brian A.

    Mapping hV4 and ventral occipital cortex: The venous eclipse Department of Psychology, Stanford: The venous eclipse. Journal of Vision, 10(5):1, 1­22, http://journalofvision.org/content/10/5/1, doi:10

  6. Brain-specific proteins in the occipital cortex of rats housed in enriched and impoverished environments

    Microsoft Academic Search

    Ole Steen Jørgensen; Elisabeth Bock

    1979-01-01

    The occipital cortex was dissected from the brain of rats housed in either enriched or impoverished environment for four weeks. In environmentally enriched rats the weight of occipital cortex was found to be increased 5.7%, compared to environmentally improverished rats, and the amount of protein was increased 6.0%. The amount of six nervous system-specific proteins was measured by crossed immunoelectrophoresis.

  7. Retinotopy and Attention in Human Occipital, Temporal, Parietal, and Frontal Cortex

    Microsoft Academic Search

    Ayse Pinar Saygin; Martin I. Sereno

    2008-01-01

    Novel mapping stimuli composed of biological motion figures were used to study the extent and layout of multiple retinotopic regions in the entire human brain and to examine the independent manipula- tion of retinotopic responses by visual stimuli and by attention. A number of areas exhibited retinotopic activations, including full or partial visual field representations in occipital cortex, the precuneus,

  8. Right Occipital Cortex Activation Correlates with Superior Odor Processing Performance in the Early Blind

    PubMed Central

    Grandin, Cécile B.; Dricot, Laurence; Plaza, Paula; Lerens, Elodie; Rombaux, Philippe; De Volder, Anne G.

    2013-01-01

    Using functional magnetic resonance imaging (fMRI) in ten early blind humans, we found robust occipital activation during two odor-processing tasks (discrimination or categorization of fruit and flower odors), as well as during control auditory-verbal conditions (discrimination or categorization of fruit and flower names). We also found evidence for reorganization and specialization of the ventral part of the occipital cortex, with dissociation according to stimulus modality: the right fusiform gyrus was most activated during olfactory conditions while part of the left ventral lateral occipital complex showed a preference for auditory-verbal processing. Only little occipital activation was found in sighted subjects, but the same right-olfactory/left-auditory-verbal hemispheric lateralization was found overall in their brain. This difference between the groups was mirrored by superior performance of the blind in various odor-processing tasks. Moreover, the level of right fusiform gyrus activation during the olfactory conditions was highly correlated with individual scores in a variety of odor recognition tests, indicating that the additional occipital activation may play a functional role in odor processing. PMID:23967263

  9. Early coding of reaching: frontal and parietal association connections of parieto-occipital cortex.

    PubMed

    Caminiti, R; Genovesio, A; Marconi, B; Mayer, A B; Onorati, P; Ferraina, S; Mitsuda, T; Giannetti, S; Squatrito, S; Maioli, M G; Molinari, M

    1999-09-01

    The ipsilateral association connections of the cortex of the dorsal part of the rostral bank of the parieto-occipital sulcus and of the adjoining posterior part of the superior parietal lobule were studied by using different retrograde fluorescent tracers. Fluoro-Ruby, Fast blue and Diamidino yellow were injected into visual area V6A, and dorso-caudal (PMdc, F2) and dorso-rostral (PMdr, F7) premotor cortex, respectively. The parietal area of injection had been previously characterized physiologically in behaving monkeys, through a variety of oculomotor and visuomanual tasks. Area V6A is mainly linked by reciprocal projections to parietal areas 7m, MIP (medial intraparietal) and PEa, and, to a lesser extent, to frontal areas PMdr (rostral dorsal premotor cortex, F7) and PMdc (F2). All these areas project to that part of the dorsocaudal premotor cortex that has a direct access to primary motor cortex. V6A is also connected to area F5 and, to a lesser extent, to 7a, ventral (VIP) and lateral (LIP) intraparietal areas. This pattern of association connections may explain the presence of visually-related and eye-position signals in premotor cortex, as well as the influence of information concerning arm position and movement direction on V6A neural activity. Area V6A emerges as a potential 'early' node of the distributed network underlying visually-guided reaching. In this network, reciprocal association connections probably impose, through re-entrant signalling, a recursive property to the operations leading to the composition of eye and hand motor commands. PMID:10510199

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

    PubMed

    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. PMID:22792493

  11. Noradrenaline transporter blockers raise extracellular dopamine in medial prefrontal but not parietal and occipital cortex: differences with mianserin and clozapine

    Microsoft Academic Search

    V. Valentini; R. Frau; G. Di Chiara

    2004-01-01

    This study compared the interaction between noradrenaline (NA) and dopamine (DA) mechanisms in the prefrontal (PFCX) and in the parietal (ParCX) and occipital (OccCX) cortex. The effect of reboxetine and desipramine, two NA transporter blockers, of mianserin, an antagonist of a2 and 5-HT2 receptors, and of clozapine, an atypical antipsychotic, on dialysate DA in the medial PFCX, ParCX and OccCX

  12. Functional subdivisions of medial parieto-occipital cortex in humans and nonhuman primates using resting-state fMRI.

    PubMed

    Hutchison, R Matthew; Culham, Jody C; Flanagan, J Randall; Everling, Stefan; Gallivan, Jason P

    2015-08-01

    Based on its diverse and wide-spread patterns of connectivity, primate posteromedial cortex (PMC) is well positioned to support roles in several aspects of sensory-, cognitive- and motor-related processing. Previous work in both humans and non-human primates (NHPs) using resting-state functional MRI (rs-fMRI) suggests that a subregion of PMC, the medial parieto-occipital cortex (mPOC), by virtue of its intrinsic functional connectivity (FC) with visual cortex, may only play a role in higher-order visual processing. Recent neuroanatomical tracer studies in NHPs, however, demonstrate that mPOC also has prominent cortico-cortical connections with several frontoparietal structures involved in movement planning and control, a finding consistent with increasing observations of reach- and grasp-related activity in the mPOC of both NHPs and humans. To reconcile these observations, here we used rs-fMRI data collected from both awake humans and anesthetized macaque monkeys to more closely examine and compare parcellations of mPOC across species and explore the FC patterns associated with these subdivisions. Seed-based and voxel-wise hierarchical cluster analyses revealed four broad spatially separated functional boundaries that correspond with graded differences in whole-brain FC patterns in each species. The patterns of FC observed are consistent with mPOC forming a critical hub of networks involved in action planning and control, spatial navigation, and working memory. In addition, our comparison between species indicates that while there are several similarities, there may be some species-specific differences in functional neural organization. These findings and the associated theoretical implications are discussed. PMID:25970649

  13. The orthographic sensitivity to written Chinese in the occipital-temporal cortex.

    PubMed

    Liu, Haicheng; Jiang, Yi; Zhang, Bo; Ma, Lifei; He, Sheng; Weng, Xuchu

    2013-06-01

    Previous studies have identified an area in the left lateral fusiform cortex that is highly responsive to written words and has been named the visual word form area (VWFA). However, there is disagreement on the specific functional role of this area in word recognition. Chinese characters, which are dramatically different from Roman alphabets in the visual form and in the form to phonological mapping, provide a unique opportunity to investigate the properties of the VWFA. Specifically, to clarify the orthographic sensitivity in the mid-fusiform cortex, we compared fMRI response amplitudes (Exp. 1) as well as the spatial patterns of response across multiple voxels (Exp. 2) between Chinese characters and stimuli derived from Chinese characters with different orthographic properties. The fMRI response amplitude results suggest the existence of orthographic sensitivity in the VWFA. The results from multi-voxel pattern analysis indicate that spatial distribution of the responses across voxels in the occipitotemporal cortex contained discriminative information between the different types of character-related stimuli. These results together suggest that the orthographic rules are likely represented in a distributed neural network with the VWFA containing the most specific information regarding a stimulus' orthographic regularity. PMID:23625045

  14. Neural mechanisms of feature conjunction learning: enduring changes in occipital cortex after a week of training.

    PubMed

    Frank, Sebastian M; Reavis, Eric A; Tse, Peter U; Greenlee, Mark W

    2014-04-01

    Most visual activities, whether reading, driving, or playing video games, require rapid detection and identification of learned patterns defined by arbitrary conjunctions of visual features. Initially, such detection is slow and inefficient, but it can become fast and efficient with training. To determine how the brain learns to process conjunctions of visual features efficiently, we trained participants over eight consecutive days to search for a target defined by an arbitrary conjunction of color and location among distractors with a different conjunction of the same features. During each training session, we measured brain activity with functional magnetic resonance imaging (fMRI). The speed of visual search for feature conjunctions improved dramatically within just a few days. These behavioral improvements were correlated with increased neural responses to the stimuli in visual cortex. This suggests that changes in neural processing in visual cortex contribute to the speeding up of visual feature conjunction search. We find evidence that this effect is driven by an increase in the signal-to-noise ratio (SNR) of the BOLD signal for search targets over distractors. In a control condition where target and distractor identities were exchanged after training, learned search efficiency was abolished, suggesting that the primary improvement was perceptual learning for the search stimuli, not task-learning. Moreover, when participants were retested on the original task after nine months without further training, the acquired changes in behavior and brain activity were still present, showing that this can be an enduring form of learning and neural reorganization. PMID:23418123

  15. Bodies are Represented as Wholes Rather Than Their Sum of Parts in the Occipital-Temporal Cortex.

    PubMed

    Brandman, Talia; Yovel, Galit

    2014-09-12

    Behavioral studies suggested that bodies are represented as wholes rather than in a part-based manner. However, neural selectivity for body stimuli is found for both whole bodies and body parts. It is therefore undetermined whether the neural representation of bodies is configural or part-based. We used functional MRI to test the role of first-order configuration on body representation in the human occipital-temporal cortex by comparing the response to a whole body versus the sum of its parts. Results show that body-selective areas, whether defined by selectivity to headless bodies or body parts, preferred whole bodies over their sum of parts and successfully decoded body configuration. This configural representation was specific to body stimuli and not found for faces. In contrast, general object areas showed no preference for wholes over parts and decoded the configuration of both bodies and faces. Finally, whereas effects of inversion on configural face representation were specific to face-selective mechanisms, effects of body inversion were not unique to body-selective mechanisms. We conclude that the neural representation of body parts is strengthened by their arrangement into an intact body, thereby demonstrating a central role of first-order configuration in the neural representation of bodies in their category-selective areas. PMID:25217470

  16. Occipital neuralgia.

    PubMed

    Dougherty, Carrie

    2014-05-01

    Occipital pain is a common complaint amongst patients with headache, and the differential can include many primary headache disorders such as cervicogenic headache or migraine. Occipital neuralgia is an uncommon cause of occipital pain characterized by paroxysmal lancinating pain in the distribution of the greater, lesser or third occipital nerves. Greater occipital nerve blockade with anesthetics and/or corticosteroids can aid in confirming the diagnosis and providing pain relief. However, nerve blocks are also effective in migraine headache and misdiagnosis can result in a false positive. Physical therapy and preventive medication with antiepileptics and tricyclic antidepressants are often effective treatments for occipital neuralgia. Refractory cases may require intervention with pulsed radiofrequency or occipital nerve stimulation. PMID:24737457

  17. The evolution of a disparity decision in human visual cortex

    PubMed Central

    Cottereau, Benoit R.; Ales, Justin M.; Norcia, Anthony M.

    2015-01-01

    We used fMRI-informed EEG source-imaging in humans to characterize the dynamics of cortical responses during a disparity-discrimination task. After the onset of a disparity-defined target, decision-related activity was found within an extended cortical network that included several occipital regions of interest (ROIs): V4, V3A, hMT+ and the Lateral Occipital Complex (LOC). By using a response-locked analysis, we were able to determine the timing relationships in this network of ROIs relative to the subject's behavioral response. Choice-related activity appeared first in the V4 ROI almost 200 ms before the button press and then subsequently in the V3A ROI. Modeling of the responses in the V4 ROI suggests that this area provides an early contribution to disparity discrimination. Choice-related responses were also found after the button-press in ROIs V4, V3A, LOC and hMT+. Outside the visual cortex, choice-related activity was found in the frontal and temporal pole before the button-press. By combining the spatial resolution of fMRI-informed EEG source imaging with the ability to sort out neural activity occurring before, during and after the behavioral manifestation of the decision, our study is the first to assign distinct functional roles to the extra-striate ROIs involved in perceptual decisions based on disparity, the primary cue for depth. PMID:24513152

  18. Memory for shape reactivates the lateral occipital complex.

    PubMed

    Karanian, Jessica M; Slotnick, Scott D

    2015-04-01

    Memory is thought to be a constructive process in which the cortical regions associated with processing event features are reactivated during retrieval. Although there is evidence for non-detailed cortical reactivation during retrieval (e.g., memory for visual or auditory information reactivates the visual or auditory processing regions, respectively), there is limited evidence that memory can reactivate cortical regions associated with processing detailed, feature-specific information. Such evidence is critical to our understanding of the mechanisms of episodic retrieval. The present functional magnetic resonance imaging (fMRI) study assessed whether the lateral occipital complex (LOC), a region that preferentially processes shape, is associated with retrieval of shape information. During encoding, participants were presented with colored abstract shapes that were either intact or scrambled. During retrieval, colored disks were presented and participants indicated whether the corresponding shape was previously "intact" or "scrambled". To assess whether conscious retrieval of intact shapes reactivated LOC, we conducted a conjunction of shape perception/encoding and accurate versus inaccurate retrieval of intact shapes, which produced many activations in LOC. To determine whether activity in LOC was specific to intact shapes, we conducted a conjunction of shape perception/encoding and intact versus scrambled shapes, which also produced many activations in LOC. Furthermore, memory for intact shapes in each hemifield produced contralateral activity in LOC (e.g., memory for left visual field intact shapes activated right LOC), which reflects the specific reinstatement of perception/encoding activity. The present results extend previous feature-specific memory reactivation evidence and support the view that memory is a constructive process. PMID:25623846

  19. Atlanto-occipital dislocation.

    PubMed

    Hall, Graham C; Kinsman, Michael J; Nazar, Ryan G; Hruska, Rob T; Mansfield, Kevin J; Boakye, Maxwell; Rahme, Ralph

    2015-03-18

    Atlanto-occipital dislocation (AOD) is being increasingly recognized as a potentially survivable injury as a result of improved prehospital management of polytrauma patients and increased awareness of this entity, leading to earlier diagnosis and more aggressive treatment. However, despite overall improved outcomes, AOD is still associated with significant morbidity and mortality. The purpose of this paper is to review the biomechanical aspects, clinical features, radiologic criteria, and treatment strategies of AOD. Given that the diagnosis of AOD can be very challenging, a high degree of clinical suspicion is essential to ensure timely recognition and treatment, thus preventing neurological decline or death. PMID:25793163

  20. Atlanto-occipital dislocation

    PubMed Central

    Hall, Graham C; Kinsman, Michael J; Nazar, Ryan G; Hruska, Rob T; Mansfield, Kevin J; Boakye, Maxwell; Rahme, Ralph

    2015-01-01

    Atlanto-occipital dislocation (AOD) is being increasingly recognized as a potentially survivable injury as a result of improved prehospital management of polytrauma patients and increased awareness of this entity, leading to earlier diagnosis and more aggressive treatment. However, despite overall improved outcomes, AOD is still associated with significant morbidity and mortality. The purpose of this paper is to review the biomechanical aspects, clinical features, radiologic criteria, and treatment strategies of AOD. Given that the diagnosis of AOD can be very challenging, a high degree of clinical suspicion is essential to ensure timely recognition and treatment, thus preventing neurological decline or death. PMID:25793163

  1. Total occipitalization of the atlas

    Microsoft Academic Search

    Mohamed Akram Al-Motabagani; Manjappa Surendra

    2006-01-01

    Occipitalization of the atlas is an important congenital malformation of the craniovertebral region because of the proximity\\u000a to the spinomedullary region. In a sample of 109 human adult skulls of Asian origin examined for evidence of atlanto-occipital\\u000a fusion, only one specimen exhibited this type of anomaly, in which the atlas was totally synostosed with the occipital bone\\u000a with multiple bony

  2. Differential processing of objects under various viewing conditions in the human lateral occipital complex.

    PubMed

    Grill-Spector, K; Kushnir, T; Edelman, S; Avidan, G; Itzchak, Y; Malach, R

    1999-09-01

    The invariant properties of human cortical neurons cannot be studied directly by fMRI due to its limited spatial resolution. Here, we circumvented this limitation by using fMR adaptation, namely, reduction of the fMR signal due to repeated presentation of identical images. Object-selective regions (lateral occipital complex [LOC]) showed a monotonic signal decrease as repetition frequency increased. The invariant properties of fMR adaptation were studied by presenting the same object in different viewing conditions. LOC exhibited stronger fMR adaptation to changes in size and position (more invariance) compared to illumination and viewpoint. The effect revealed two putative subdivisions within LOC: caudal-dorsal (LO), which exhibited substantial recovery from adaptation under all transformations, and posterior fusiform (PF/LOa), which displayed stronger adaptation. This study demonstrates the utility of fMR adaptation for revealing functional characteristics of neurons in fMRI studies. PMID:10677037

  3. Downstream targets of methyl CpG binding protein 2 and their abnormal expression in the frontal cortex of the human Rett syndrome brain

    E-print Network

    Gibson, Joanne H

    Background: The Rett Syndrome (RTT) brain displays regional histopathology and volumetric reduction, with frontal cortex showing such abnormalities, whereas the occipital cortex is relatively less affected. Results: Using ...

  4. Occipital seizures imitating migraine aura.

    PubMed Central

    Panayiotopoulos, C P; Sharoqi, I A; Agathonikou, A

    1997-01-01

    Three cases are reported in which symptoms of occipital seizures resembled the visual aura of migraine. Careful recording of the characteristics and timing of such visual effects will often resolve the diagnostic dilemma. PMID:9204019

  5. Occipital cortical thickness predicts performance on pitch and musical tasks in blind individuals.

    PubMed

    Voss, Patrice; Zatorre, Robert J

    2012-11-01

    The behavioral and neurofunctional consequences of blindness often include performance enhancements and recruitment of occipital regions for nonvisual tasks. How the neuroanatomical changes resulting from this sensory loss relate to these functional changes is, however, less clear. Previous studies using cortical thickness (CT) measures have shown thicker occipital cortex in early-blind (EB) individuals compared with sighted controls. We hypothesized that this finding reflects the crossmodal plasticity often observed in blind individuals and thus could reflect behavioral adaptations. To address this issue, CT measures in blind (early and late) and sighted subjects were obtained along with several auditory behavioral measures in an attempt to relate behavioral and neuroanatomical changes. Group contrasts confirmed previous results in showing thicker occipital cortex in the EB. Regression analyses between CT measures across the whole brain of all blind individuals with the behavioral scores from 2 tasks in which EB subjects were superior (pitch and melody discrimination) showed that CT of occipital areas was directly related to behavioral enhancements. These findings constitute a compelling demonstration that anatomical changes in occipital areas are directly related to heightened behavioral abilities in the blind and hence support the idea that these anatomical features reflect adaptive compensatory plasticity. PMID:22095215

  6. Concurrent occipital hypoplasia, occipital dysplasia, syringohydromyelia, and hydrocephalus in a Yorkshire terrier

    PubMed Central

    Cagle, Laura

    2010-01-01

    Magnetic resonance imaging of a 7.5-year-old neutered male Yorkshire terrier with mild generalized ataxia and intermittent neck scratching led to a diagnosis of caudal occipital malformation and syringohydromyelia. Surgical exploration led to a diagnosis of occipital dysplasia with concurrent occipital hypoplasia. Following a dorsal laminectomy of the first cervical vertebra there was no progression or improvement a month later. PMID:21037897

  7. Traumatic AtlantoOccipital Dislocation in Children

    Microsoft Academic Search

    Paul Houle; Dennis E. McDonnell; John Vender

    2001-01-01

    Traumatic atlanto-occipital dislocation is seen in approximately 25% of fatal pediatric trauma. This was previously considered to be a rare and fatal entity, however with improvements in resuscitation in the field, many patients who previously might have died are now evaluated in the hospital. Treatment of atlanto-occipital instability is internal fixation. Many authors have advocated supplemental external immobilization with a

  8. Traumatic atlanto-occipital disruption in children

    Microsoft Academic Search

    C. K. Maves; A. Souza; E. C. Prenger; D. R. Kirks

    1991-01-01

    Ten cases of traumatic atlanto-occipital disruption in pediatric patients are reported. All injuries resulted from motor vehicle accidents, the majority of which were pedestrian\\/automobile. Three patients survived their injury for a period greater than one year. The importance of recognizing atlanto-occipital disruption is stressed because of its relative frequency in severely traumatized pediatric patients, particularly pedestrian\\/vehicle incidents, and because of

  9. Identification of greater occipital nerve landmarks for the treatment of occipital neuralgia.

    PubMed

    Loukas, M; El-Sedfy, A; Tubbs, R S; Louis, R G; Wartmann, C H T; Curry, B; Jordan, R

    2006-11-01

    Important structures involved in the pathogenesis of occipital headache include the aponeurotic attachments of the trapezius and semispinalis capitis muscles to the occipital bone. The greater occipital nerve (GON) can become entrapped as it passes through these aponeuroses, causing symptoms of occipital neuralgia. The aim of this study was to identify topographic landmarks for accurate identification of GON, which might facilitate its anaesthetic blockade. The course and distribution of GON and its relation to the aponeuroses of the trapezius and semispinalis capitis were examined in 100 formalin-fixed adult cadavers. In addition, the relative position of the nerve on a horizontal line between the external occipital protuberance and the mastoid process, as well as between the mastoid processes was measured. The greater occipital nerve was found bilaterally in all specimens. It was located at a mean distance of 3.8 cm (range 1.5-7.5 cm) lateral to a vertical line through the external occipital protuberance and the spinous processes of the cervical vertebrae 2-7. It was also located approximately 41% of the distance along the intermastoid line (medial to a mastoid process) and 22% of the distance between the external occipital protuberance and the mastoid process. The location of GON for anaesthesia or any other neurosurgical procedure has been established as one thumb's breadth lateral to the external occipital protuberance (2 cm laterally) and approximately at the base of the thumb nail (2 cm inferior). This is the first study proposing the use of landmarks in relation to anthropometric measurements. On the basis of these observations we propose a target zone for local anaesthetic injection that is based on easily identifiable landmarks and suggest that injection at this target point could be of benefit in the relief of occipital neuralgia. PMID:17171613

  10. Involvement of prefrontal cortex in visual search

    Microsoft Academic Search

    E. J. Anderson; S. K. Mannan; M. Husain; G. Rees; P. Sumner; D. J. Mort; D. McRobbie; C. Kennard

    2007-01-01

    Visual search for target items embedded within a set of distracting items has consistently been shown to engage regions of\\u000a occipital and parietal cortex, but the contribution of different regions of prefrontal cortex remains unclear. Here, we used\\u000a fMRI to compare brain activity in 12 healthy participants performing efficient and inefficient search tasks in which target\\u000a discriminability and the number

  11. A case of occipital gnathostomiasis in Thailand.

    PubMed

    Nitidandhaprabhas, P; Harnsomburana, K; Surasvadi, C; Mahunee, W

    1978-01-01

    A large subcutaneous nodule present for 2 mo was removed from the occiput of a 26-yr-old Thai man and found to contain a male Gnathostoma spinigerum. Aside from the occipital location, a noteworthy feature of the case was the long stationary persistence of the stable, non-tender nodule. PMID:626275

  12. Visual angle of the mind's eye before and after unilateral occipital lobectomy.

    PubMed

    Farah, M J; Soso, M J; Dasheiff, R M

    1992-02-01

    Do mental images occur in a spatially mapped (i.e., analog, or array-format) representational medium? Kosslyn's (1978) method was used to measure the visual angle of "the mind's eye" to estimate the extent of the imagery medium before and after unilateral occipital lobectomy. It was found that the overall size of the largest possible image was reduced following the surgery. In addition, only the horizontal extent, and not the vertical extent, of the imagery medium was reduced. Finally, it was determined that the S understood the tasks, was not aware of our predictions, and was unaffected by a strong demand characteristic in a different imagery task. These results are consistent with the hypothesis that imagery occurs in a spatially mapped representational medium dependent on occipital cortex. PMID:1532190

  13. Amount of lifetime video gaming is positively associated with entorhinal, hippocampal and occipital volume.

    PubMed

    Kühn, S; Gallinat, J

    2014-07-01

    Playing video games is a popular leisure activity among children and adults, and may therefore potentially influence brain structure. We have previously shown a positive association between probability of gray matter (GM) volume in the ventral striatum and frequent video gaming in adolescence. Here we set out to investigate structural correlates of video gaming in adulthood, as the effects observed in adolescents may reflect only a fraction of the potential neural long-term effects seen in adults. On magnetic resonance imaging (MRI) scans of 62 male adults, we computed voxel-based morphometry to explore the correlation of GM with the lifetime amount of video gaming (termed joystick years). We found a significant positive association between GM in bilateral parahippocamal region (entorhinal cortex) and left occipital cortex/inferior parietal lobe and joystick years (P<0.001, corrected for multiple comparisons). An exploratory analysis showed that the entorhinal GM volume can be predicted by the video game genres played, such as logic/puzzle games and platform games contributing positively, and action-based role-playing games contributing negatively. Furthermore, joystick years were positively correlated with hippocampus volume. The association of lifetime amount of video game playing with bilateral entorhinal cortex, hippocampal and occipital GM volume could reflect adaptive neural plasticity related to navigation and visual attention. PMID:23958958

  14. Occipitalized os odontoideum: A case report.

    PubMed

    Ohya, Junich; Miyoshi, Kota; Kitagawa, Tomoaki; Nakagawa, Shogo

    2014-10-01

    We report on a 36-year-old man presenting with a sudden onset of motor weakness and numbness in the upper extremities following a fall from a truck bed. Radiological findings demonstrated an os odontoideum and osseous continuity between the occiput and an ossicle, termed an "occipitalized os odontoideum." The occipitalized ossicle and atlas moved as a functional unit from the body of the axis. He underwent atlantoasxial stabilization with an atlas lateral mass screw and axis pedicle screw. Eighteen months later, he remained free of symptoms and showed solid bone fusion. Atlantoaxial stabilization resulted in an excellent clinical outcome for this condition. Our report provides useful knowledge regarding treatment of extremely rare osseous anomalies in the craniovertebral junction. PMID:25558149

  15. LocSigDB: a database of protein localization signals

    PubMed Central

    Negi, Simarjeet; Pandey, Sanjit; Srinivasan, Satish M.; Mohammed, Akram; Guda, Chittibabu

    2015-01-01

    LocSigDB (http://genome.unmc.edu/LocSigDB/) is a manually curated database of experimental protein localization signals for eight distinct subcellular locations; primarily in a eukaryotic cell with brief coverage of bacterial proteins. Proteins must be localized at their appropriate subcellular compartment to perform their desired function. Mislocalization of proteins to unintended locations is a causative factor for many human diseases; therefore, collection of known sorting signals will help support many important areas of biomedical research. By performing an extensive literature study, we compiled a collection of 533 experimentally determined localization signals, along with the proteins that harbor such signals. Each signal in the LocSigDB is annotated with its localization, source, PubMed references and is linked to the proteins in UniProt database along with the organism information that contain the same amino acid pattern as the given signal. From LocSigDB webserver, users can download the whole database or browse/search for data using an intuitive query interface. To date, LocSigDB is the most comprehensive compendium of protein localization signals for eight distinct subcellular locations. Database URL: http://genome.unmc.edu/LocSigDB/ PMID:25725059

  16. A preliminary examination of Loss of Control Eating Disorder (LOC-ED) in middle childhood.

    PubMed

    Matherne, Camden E; Tanofsky-Kraff, Marian; Altschul, Anne M; Shank, Lisa M; Schvey, Natasha A; Brady, Sheila M; Galescu, Ovidiu; Demidowich, Andrew P; Yanovski, Susan Z; Yanovski, Jack A

    2015-08-01

    Loss of Control Eating Disorder (LOC-ED) has been proposed as a diagnostic category for children 6-12years with binge-type eating. However, characteristics of youth with LOC-ED have not been examined. We tested the hypothesis that the proposed criteria for LOC-ED would identify children with greater adiposity, more disordered eating attitudes, and greater mood disturbance than those without LOC-ED. Participants were 251 youth (10.29years±1.54, 53.8% female, 57.8% White, 35.5% Black, 2.0% Asian, 4.8% Hispanic, 53.0% overweight). Youth were interviewed regarding eating attitudes and behaviors, completed questionnaires to assess general psychopathology, and underwent measurements of body fat mass. Using previously proposed criteria for LOC-ED, children were classified as LOC-ED (n=19), LOC in the absence of the full disorder (subLOC, n=33), and youth not reporting LOC (noLOC, n=199). LOC-ED youth had higher BMIz (p=0.001) and adiposity (p=0.003) and reported greater disordered eating concerns (p<0.001) compared to noLOC youth. Compared to subLOC youth, LOC-ED youth had non-significantly higher BMIz (p=0.11), and significantly higher adiposity (p=0.04) and disordered eating attitudes (p=0.02). SubLOC youth had greater disordered eating concerns (p<0.001) and BMIz (p=0.03) but did not differ in adiposity (p=0.33) compared to noLOC youth. These preliminary data suggest that LOC-ED youth are elevated on disordered eating cognitions and anthropometric measures compared to youth without LOC-ED. Longitudinal studies are needed to determine if those with LOC-ED are at particularly increased risk for progression of disordered eating and excess weight gain. PMID:25913008

  17. Occipital Neuralgia after Occipital Cervical Fusion to Treat an Unstable Jefferson Fracture

    PubMed Central

    Kong, Seong Ju; Park, Jin Hoon

    2012-01-01

    In this report we describe a patient with an unstable Jefferson fracture who was treated by occipitocervical fusion and later reported sustained postoperative occipital neuralgia. A 70-year-old male was admitted to our center with a Jefferson fracture induced by a car accident. Preoperative lateral X-ray revealed an atlanto-dens interval of 4.8mm and a C1 canal anterior-posterior diameter of 19.94mm. We performed fusion surgery from the occiput to C5 without decompression of C1. The patient reported sustained continuous pain throughout the following year despite strong analgesics. The pain dermatome was located mainly in the great occipital nerve territory and posterior neck. Magnetic resonance images revealed no evidence of cord compression, however a C1 lamina compressed dural sac and C2 root compression could not be excluded. We performed bilateral C2 root decompression via a C1 laminectomy. After decompression, bilateral C2 root redundancy was identified by palpation. After decompression surgery, pain was reduced. This case indicates that occipital neuralgia, suggesting the need for diagnostic block, should be considered in the differential diagnosis of patients with sustained occipital headache after occipitocervical fusion surgery. PMID:25983846

  18. Occipital neuralgia after occipital cervical fusion to treat an unstable jefferson fracture.

    PubMed

    Kong, Seong Ju; Park, Jin Hoon; Roh, Sung Woo

    2012-12-01

    In this report we describe a patient with an unstable Jefferson fracture who was treated by occipitocervical fusion and later reported sustained postoperative occipital neuralgia. A 70-year-old male was admitted to our center with a Jefferson fracture induced by a car accident. Preoperative lateral X-ray revealed an atlanto-dens interval of 4.8mm and a C1 canal anterior-posterior diameter of 19.94mm. We performed fusion surgery from the occiput to C5 without decompression of C1. The patient reported sustained continuous pain throughout the following year despite strong analgesics. The pain dermatome was located mainly in the great occipital nerve territory and posterior neck. Magnetic resonance images revealed no evidence of cord compression, however a C1 lamina compressed dural sac and C2 root compression could not be excluded. We performed bilateral C2 root decompression via a C1 laminectomy. After decompression, bilateral C2 root redundancy was identified by palpation. After decompression surgery, pain was reduced. This case indicates that occipital neuralgia, suggesting the need for diagnostic block, should be considered in the differential diagnosis of patients with sustained occipital headache after occipitocervical fusion surgery. PMID:25983846

  19. iLoc-Animal: a multi-label learning classifier for predicting subcellular localization of animal proteins.

    PubMed

    Lin, Wei-Zhong; Fang, Jian-An; Xiao, Xuan; Chou, Kuo-Chen

    2013-04-01

    Predicting protein subcellular localization is a challenging problem, particularly when query proteins have multi-label features meaning that they may simultaneously exist at, or move between, two or more different subcellular location sites. Most of the existing methods can only be used to deal with the single-label proteins. Actually, multi-label proteins should not be ignored because they usually bear some special function worthy of in-depth studies. By introducing the "multi-label learning" approach, a new predictor, called iLoc-Animal, has been developed that can be used to deal with the systems containing both single- and multi-label animal (metazoan except human) proteins. Meanwhile, to measure the prediction quality of a multi-label system in a rigorous way, five indices were introduced; they are "Absolute-True", "Absolute-False" (or Hamming-Loss"), "Accuracy", "Precision", and "Recall". As a demonstration, the jackknife cross-validation was performed with iLoc-Animal on a benchmark dataset of animal proteins classified into the following 20 location sites: (1) acrosome, (2) cell membrane, (3) centriole, (4) centrosome, (5) cell cortex, (6) cytoplasm, (7) cytoskeleton, (8) endoplasmic reticulum, (9) endosome, (10) extracellular, (11) Golgi apparatus, (12) lysosome, (13) mitochondrion, (14) melanosome, (15) microsome, (16) nucleus, (17) peroxisome, (18) plasma membrane, (19) spindle, and (20) synapse, where many proteins belong to two or more locations. For such a complicated system, the outcomes achieved by iLoc-Animal for all the aforementioned five indices were quite encouraging, indicating that the predictor may become a useful tool in this area. It has not escaped our notice that the multi-label approach and the rigorous measurement metrics can also be used to investigate many other multi-label problems in molecular biology. As a user-friendly web-server, iLoc-Animal is freely accessible to the public at the web-site . PMID:23370050

  20. Coherent Activity in Bilateral Parieto-Occipital Cortices during P300-BCI Operation.

    PubMed

    Takano, Kouji; Ora, Hiroki; Sekihara, Kensuke; Iwaki, Sunao; Kansaku, Kenji

    2014-01-01

    The visual P300 brain-computer interface (BCI), a popular system for electroencephalography (EEG)-based BCI, uses the P300 event-related potential to select an icon arranged in a flicker matrix. In earlier studies, we used green/blue (GB) luminance and chromatic changes in the P300-BCI system and reported that this luminance and chromatic flicker matrix was associated with better performance and greater subject comfort compared with the conventional white/gray (WG) luminance flicker matrix. To highlight areas involved in improved P300-BCI performance, we used simultaneous EEG-fMRI recordings and showed enhanced activities in bilateral and right lateralized parieto-occipital areas. Here, to capture coherent activities of the areas during P300-BCI, we collected whole-head 306-channel magnetoencephalography data. When comparing functional connectivity between the right and left parieto-occipital channels, significantly greater functional connectivity in the alpha band was observed under the GB flicker matrix condition than under the WG flicker matrix condition. Current sources were estimated with a narrow-band adaptive spatial filter, and mean imaginary coherence was computed in the alpha band. Significantly greater coherence was observed in the right posterior parietal cortex under the GB than under the WG condition. Re-analysis of previous EEG-based P300-BCI data showed significant correlations between the power of the coherence of the bilateral parieto-occipital cortices and their performance accuracy. These results suggest that coherent activity in the bilateral parieto-occipital cortices plays a significant role in effectively driving the P300-BCI. PMID:24860546

  1. Auditory Attention Activates Peripheral Visual Cortex

    Microsoft Academic Search

    Anthony D. Cate; Timothy J. Herron; E. William Yund; G. Christopher Stecker; Teemu Rinne; Xiaojian Kang; Christopher I. Petkov; Elizabeth A. Disbrow; David L. Woods; Paul L. Gribble

    2009-01-01

    BackgroundRecent neuroimaging studies have revealed that putatively unimodal regions of visual cortex can be activated during auditory tasks in sighted as well as in blind subjects. However, the task determinants and functional significance of auditory occipital activations (AOAs) remains unclear.Methodology\\/Principal FindingsWe examined AOAs in an intermodal selective attention task to distinguish whether they were stimulus-bound or recruited by higher-level cognitive

  2. Traumatic atlanto-occipital dislocation: A potentially survivable injury

    Microsoft Academic Search

    Peter C Ferrera; Joel M Bartfield

    1996-01-01

    Although survival with traumatic atlanto-occipital dislocation (AOD) is rare, there have been reports of victims who have sustained this injury with good neurological outcome. Plain lateral cervical spine radiography is the initial diagnostic procedure but may miss subtle dislocations. Several methods for the interpretation of the normal atlanto-occipital alignment have been devised and are discussed. Computed tomography (CT) and magnetic

  3. Feasibility of Ultrasound Guided Atlanto-occipital Joint Injection

    PubMed Central

    Won, Sun Jae; Lee, U-Young; Rhee, Won Ihl

    2012-01-01

    Objective To evaluate the feasibility of ultrasound guided atlanto-occipital joint injection. Method Six atlanto-occipital joints of three cadavers were examined. Cadavers were placed in prone position with their head slightly rotated towards the contra-lateral side. The atlanto-occipital joint was initially identified with a longitudinal ultrasound scan at the midline between occipital protuberance and mastoid process. Contrast media 0.5cc was injected into the atlanto-occipital joint using an in-plane needle approach under ultrasound guide. The location of the needle tip and spreading pattern of the contrast was confirmed by fluoroscopic evaluation. Results After ultrasound guided atlanto-occipital joint injection, spreading of the contrast media into the joint was seen in all the injected joints in the anterior-posterior fluoroscopic view. Conclusion The ultrasound guided atlanto-occipital injection is feasible. The ultrasound guided injection by Doppler examination can provide a safer approach to the atlanto-occipital joint. PMID:23185726

  4. Traumatic atlanto-occipital dislocation in children.

    PubMed

    Astur, Nelson; Sawyer, Jeffrey R; Klimo, Paul; Kelly, Derek M; Muhlbauer, Michael; Warner, William C

    2014-05-01

    Although once considered an invariably fatal injury, improvements in diagnosis and management have made atlanto-occipital dislocation (AOD) a survivable injury. MRI is the preferred imaging modality; occasionally, flexion/extension/distraction fluoroscopy may be required to determine craniovertebral stability. Early surgical stabilization is recommended for all children with AOD. Early occipitocervical fusion using screws in combination with a rod or plate, or sublaminar wires with a contoured rod, coupled with autograft bone, provide immediate stabilization and a high fusion rate. Halo immobilization and traction are contraindicated in the management of AOD in children because of the risk of displacement of the injured occipitocervical joint. Postoperative hydrocephalus is frequent and should be suspected when neurologic decline occurs after fixation. Nearly half of children who survive AOD will have residual neurologic deficits. PMID:24788443

  5. Context-specific differences in fronto-parieto-occipital effective connectivity during short-term memory maintenance.

    PubMed

    Kundu, Bornali; Chang, Jui-Yang; Postle, Bradley R; Van Veen, Barry D

    2015-07-01

    Although visual short-term memory (VSTM) performance has been hypothesized to rely on two distinct mechanisms, capacity and filtering, the two have not been dissociated using network-level causality measures. Here, we hypothesized that behavioral tasks challenging capacity or distraction filtering would both engage a common network of areas, namely dorsolateral prefrontal cortex (dlPFC), superior parietal lobule (SPL), and occipital cortex, but would do so according to dissociable patterns of effective connectivity. We tested this by estimating directed connectivity between areas using conditional Granger causality (cGC). Consistent with our prediction, the results indicated that increasing mnemonic load (capacity) increased the top-down drive from dlPFC to SPL, and cGC in the alpha (8-14Hz) frequency range was a predominant component of this effect. The presence of distraction during encoding (filtering), in contrast, was associated with increased top-down drive from dlPFC to occipital cortices directly and from SPL to occipital cortices directly, in both cases in the beta (15-25Hz) range. Thus, although a common anatomical network may serve VSTM in different contexts, it does so via specific functions that are carried out within distinct, dynamically configured frequency channels. PMID:25863155

  6. Non-traumatic posterior atlanto-occipital joint dislocation.

    PubMed

    Takechi, Yasuhiko; Iizuka, Haku; Sorimachi, Yasunori; Ara, Tsuyoshi; Nishinome, Masahiro; Takagishi, Kenji

    2011-07-01

    This report presents a case of non-traumatic posterior atlanto-occipital dislocation. A 36-year-old female was referred with a history of numbness of the extremities, vertigo and neck pain for 1 year. The patient had no history of trauma. The axial rotation of range of motion of the cervical spine was severely restricted. A lateral cervical radiograph in the neutral position demonstrated a posterior atlanto-occipital dislocation. A coronal view on a computed tomography (CT) reconstruction image showed a loss of angle of the bilateral atlanto-occipital joint, and a sagittal reconstruction view of CT images also demonstrated flatness of atlanto-occipital joint. Instrumented occipito-cervical fusion was performed after reduction. A lateral cervical radiograph in the neutral position 1 year after surgery showed the reduction of atlanto-occipital joint, moreover, it was maintained even in an extended position. The patient had neurologic improvement after surgery. Flatness of the bilateral atlanto-occipital joint may have induced this instability. Occipital-cervical fusion was chosen in the present case since the patient showed restricted axial rotation of the neck before surgery. The surgery improved the preoperative symptoms including the function of cervical spine evaluated by JOACMEQ. PMID:20549257

  7. Anton's Syndrome due to Bilateral Ischemic Occipital Lobe Strokes

    PubMed Central

    Zuki?, Sanela; Sinanovi?, Osman; Hodži?, Renata; Mujagi?, Svjetlana; Smajlovi?, Edina

    2014-01-01

    We present a case of a patient with Anton's syndrome (i.e., visual anosognosia with confabulations), who developed bilateral occipital lobe infarct. Bilateral occipital brain damage results in blindness, and patients start to confabulate to fill in the missing sensory input. In addition, the patient occasionally becomes agitated and talks to himself, which indicates that, besides Anton's syndrome, he might have had Charles Bonnet syndrome, characterized by both visual loss and hallucinations. Anton syndrome, is not so frequent condition and is most commonly caused by ischemic stroke. In this particular case, the patient had successive bilateral occipital ischemia as a result of massive stenoses of head and neck arteries. PMID:25530893

  8. Neonatal apneic seizure of occipital lobe origin: continuous video-EEG recording.

    PubMed

    Castro Conde, José Ramón; González-Hernández, Tomás; González Barrios, Desiré; González Campo, Candelaria

    2012-06-01

    We present 2 term newborn infants with apneic seizure originating in the occipital lobe that was diagnosed by video-EEG. One infant had ischemic infarction in the distribution of the posterior cerebral artery, extending to the cingulate gyrus. In the other infant, only transient occipital hyperechogenicity was observed by using neurosonography. In both cases, although the critical EEG discharge was observed at the occipital level, the infants presented no clinical manifestations. In patient 1, the discharge extended to the temporal lobe first, with subtle motor manifestations and tachycardia, then synchronously to both hemispheres (with bradypnea/hypopnea), and the background EEG activity became suppressed, at which point the infant experienced apnea. In patient 2, background EEG activity became suppressed right at the end of the focal discharge, coinciding with the appearance of apnea. In neither case did the clinical description by observers coincide with video-EEG findings. The existence of connections between the posterior limbic cortex and the temporal lobe and midbrain respiratory centers may explain the clinical symptoms recorded in these 2 cases. The novel features reported here include video-EEG capture of apneic seizure, ischemic lesion in the territory of the posterior cerebral artery as the cause of apneic seizure, and the appearance of apnea when the epileptiform ictal discharge extended to other cerebral areas or when EEG activity became suppressed. To date, none of these clinical findings have been previously reported. We believe this pathology may in fact be fairly common, but that video-EEG monitoring is essential for diagnosis. PMID:22641764

  9. Survivor of a traumatic atlanto-occipital dislocation

    Microsoft Academic Search

    M. Ehlinger; Y.-P. Charles; P. Adam; G. Bierry; J.-C. Dosch; J.-P. Steib; F. Bonnomet

    2011-01-01

    Atlanto-occipital dislocation is a devastating ligamentous injury that most often turns fatal. However, because of on-site resuscitation improvements, the emergency teams are increasingly dealing with this condition. We report a rare case of atlanto-occipital dislocation (AOD) in a surviving patient with more than one-year follow-up. The mechanism of injury appears to be an extreme hyperextension applied to the head. This

  10. Treatment of traumatic atlanto-occipital dislocation in chronic phase

    Microsoft Academic Search

    M. Takayasu; Masahito Hara; Yoshio Suzuki; Jun Yoshida

    1999-01-01

    We report the case of 27-year-old woman who presented with mild neurological deficits with significant anterior dislocation\\u000a of the atlanto-occipital junction in a chronic phase after initial conservative treatment in another hospital. The importance\\u000a of early diagnosis and treatment for atlanto-occipital dislocation is emphasized. The dislocation could not be reduced sufficiently\\u000a either by halo ring cervical traction or surgical procedure

  11. Occipital condyle syndrome secondary to bone metastases from rectal cancer

    Microsoft Academic Search

    Jordi Marruecos; Carlos Conill; Izaskun Valduvieco; Mauricio Vargas; Joan Berenguer; Joan Maurel

    2008-01-01

    Skull-base metastases are very unfrequent. Occipital condyle syndrome (OCS) is usually underdiagnosed. Until now few cases\\u000a have been reported in the literature. We present a 71-year-old woman with metastatic rectum adenocarcinoma, with right occipital\\u000a headache and ipsilateral hypoglossal palsy, diagnosed by computed tomography and magnetic resonance imaging of OCS due to\\u000a a skull-base metastasis and treated with radiation therapy.

  12. Occipital condyle syndrome secondary to bone metastases from rectal cancer.

    PubMed

    Marruecos, J; Conill, C; Valduvieco, I; Vargas, M; Berenguer, J; Maurel, J

    2008-01-01

    Skull-base metastases are very unfrequent. Occipital condyle syndrome (OCS) is usually underdiagnosed. Until now few cases have been reported in the literature. We present a 71-year-old woman with metastatic rectum adenocarcinoma, with right occipital headache and ipsilateral hypoglossal palsy, diagnosed by computed tomography and magnetic resonance imaging of OCS due to a skull-base metastasis and treated with radiation therapy. PMID:18208794

  13. The Classical Pathways of Occipital Lobe Epileptic Propagation Revised in the Light of White Matter Dissection

    PubMed Central

    Latini, Francesco; Hjortberg, Mats; Aldskogius, Håkan; Ryttlefors, Mats

    2015-01-01

    The clinical evidences of variable epileptic propagation in occipital lobe epilepsy (OLE) have been demonstrated by several studies. However the exact localization of the epileptic focus sometimes represents a problem because of the rapid propagation to frontal, parietal, or temporal regions. Each white matter pathway close to the supposed initial focus can lead the propagation towards a specific direction, explaining the variable semiology of these rare epilepsy syndromes. Some new insights in occipital white matter anatomy are herein described by means of white matter dissection and compared to the classical epileptic patterns, mostly based on the central position of the primary visual cortex. The dissections showed a complex white matter architecture composed by vertical and longitudinal bundles, which are closely interconnected and segregated and are able to support specific high order functions with parallel bidirectional propagation of the electric signal. The same sublobar lesions may hyperactivate different white matter bundles reemphasizing the importance of the ictal semiology as a specific clinical demonstration of the subcortical networks recruited. Merging semiology, white matter anatomy, and electrophysiology may lead us to a better understanding of these complex syndromes and tailored therapeutic options based on individual white matter connectivity. PMID:26063964

  14. Spatial attention enhances object coding in local and distributed representations of the lateral occipital complex.

    PubMed

    Guggenmos, Matthias; Thoma, Volker; Haynes, John-Dylan; Richardson-Klavehn, Alan; Cichy, Radoslaw Martin; Sterzer, Philipp

    2015-08-01

    The modulation of neural activity in visual cortex is thought to be a key mechanism of visual attention. The investigation of attentional modulation in high-level visual areas, however, is hampered by the lack of clear tuning or contrast response functions. In the present functional magnetic resonance imaging study we therefore systematically assessed how small voxel-wise biases in object preference across hundreds of voxels in the lateral occipital complex were affected when attention was directed to objects. We found that the strength of attentional modulation depended on a voxel's object preference in the absence of attention, a pattern indicative of an amplificatory mechanism. Our results show that such attentional modulation effectively increased the mutual information between voxel responses and object identity. Further, these local modulatory effects led to improved information-based object readout at the level of multi-voxel activation patterns and to an increased reproducibility of these patterns across repeated presentations. We conclude that attentional modulation enhances object coding in local and distributed object representations of the lateral occipital complex. PMID:25865144

  15. Traumatic Atlanto-occipital Dislocation (AOD)

    PubMed Central

    Kim, Yeon-Joon; Park, Chan-Woo; Lee, Sang-Gu; Son, Seong; Kim, Woo-Kyung

    2012-01-01

    Objective Traumatic atlanto-occipital dislocation (AOD) results from high energy trauma and is an uncommon and usually fatal injury due to an injury to the cervicomedullary junction. Recently, improved prehospital management, early diagnosis and effective treatment led to increasing reports of survival. This study of patients with AOD initial imaging modalities recognizes the clinical features and diagnostic considerations for a quick diagnosis. Methods In this article, five survived adult patients with traumatic AOD are presented and retrospectively reviewed. Diagnosis was made by lateral cervical spine x-ray, cervical computed tomography (CT), or magnetic resonance imaging(MRI). Treatment consisted of early immobilization, respiratory support, and subsequent occipitocervical fusion. Results Four patients were male and the other one was female. Three were diagnosed early and the others were delayed in confirmations. One was type I AOD and four were type II AOD. All patients were applied occipitocervical fusion. Two cases were worse; neurological states and the other three that showed no change. Lateral X-ray film of all patients in the prevertebral soft tissue swelling at the C2 level was noted. The mean thickness of prevertebral soft tissue C2 level was 17.88 mm(15.18 to 20.17mm). Two were in the normal range of dens-basion index(DBI), three showed abnormalities, and Power's ratio was abnormal in 3 patients. Conclusion As for damages caused by a strong external force in patients with severe prevertebral soft tissue swelling at C2 level abnormaly, the doctor determines whether more should be carefully AOD and considers 3D CT or MRI to confirm AOD in these patients. PMID:25983794

  16. Occipital long-interval paired pulse TMS leads to slow wave components in NREM sleep.

    PubMed

    Stamm, Mihkel; Aru, Jaan; Rutiku, Renate; Bachmann, Talis

    2015-09-01

    Neural correlates of conscious vs unconscious states can be studied by contrasting EEG markers of brain activity between those two states. Here, a task-free experimental setup was used to study the state dependent effects of occipital transcranial magnetic stimulation (TMS). EEG responses to single and paired pulse TMS with an inter-stimulus-interval (ISI) of 100ms were investigated under Non-REM (NREM) sleep and wakefulness. In the paired pulse TMS condition adopting this long ISI, a robust positive deflection starting around 200ms after the second pulse was found. This component was not obtained under wakefulness or when a single TMS pulse was applied in sleep. These findings are discussed in the context of NREM sleep slow waves. The present results indicate that the long interval paired-pulse paradigm could be used to manipulate plasticity processes in the visual cortex. The present setup might also become useful for evaluating states of consciousness. PMID:25978462

  17. Genetic and Functional Dissection of HTRA1 and LOC387715 in Age-Related Macular Degeneration

    Microsoft Academic Search

    Zhenglin Yang; Zongzhong Tong; Yuhong Chen; Jiexi Zeng; Fang Lu; Xufang Sun; Chao Zhao; Kevin Wang; Lisa Davey; Haoyu Chen; Nyall London; Daisuke Muramatsu; Francesca Salasar; Ruben Carmona; Daniel Kasuga; Xiaolei Wang; Matthew Bedell; Manjuxia Dixie; Peiquan Zhao; Ruifu Yang; Daniel Gibbs; Xiaoqi Liu; Yan Li; Cai Li; Yuanfeng Li; Betsy Campochiaro; Ryan Constantine; Donald J. Zack; Peter Campochiaro; Yinbin Fu; Dean Y. Li; Nicholas Katsanis; Kang Zhang

    2010-01-01

    A common haplotype on 10q26 influences the risk of age-related macular degeneration (AMD) and encompasses two genes, LOC387715 and HTRA1. Recent data have suggested that loss of LOC387715, mediated by an insertion\\/deletion (in\\/del) that destabilizes its message, is causally related with the disorder. Here we show that loss of LOC387715 is insufficient to explain AMD susceptibility, since a nonsense mutation

  18. Occipital condyle to cervical spine fixation in the pediatric population.

    PubMed

    Kosnik-Infinger, Libby; Glazier, Steven S; Frankel, Bruce M

    2014-01-01

    Fixation at the craniovertebral junction (CVJ) is necessary in a variety of pediatric clinical scenarios. Traditionally an occipital bone to cervical fusion is preformed, which requires a large amount of hardware to be placed on the occiput of a child. If a patient has previously undergone a posterior fossa decompression or requires a decompression at the time of the fusion procedure, it can be difficult to anchor a plate to the occipital bone. The authors propose a technique that can be used when faced with this difficult challenge by using the occipital condyle as a point of fixation for the construct. Adult cadaveric and a limited number of case studies have been published using occipital condyle (C-0) fixation. This work was adapted for the pediatric population. Between 2009 and 2012, 4 children underwent occipital condyle to axial or subaxial spine fixation. One patient had previously undergone posterior fossa surgery for tumor resection, and 1 required decompression at the time of operation. Two patients underwent preoperative deformity reduction using traction. One child had a Chiari malformation Type I. Each procedure was performed using polyaxial screw-rod constructs with intraoperative neuronavigation supplemented by a custom navigational drill guide. Smooth-shanked 3.5-mm polyaxial screws, ranging in length from 26 to 32 mm, were placed into the occipital condyles. All patients successfully underwent occipital condyle to cervical spine fixation. In 3 patients the construct extended from C-0 to C-2, and in 1 from C-0 to T-2. Patients with preoperative halo stabilization were placed in a cervical collar postoperatively. There were no new postoperative neurological deficits or vascular injuries. Each patient underwent postoperative CT, demonstrating excellent screw placement and evidence of solid fusion. Occipital condyle fixation is an effective option in pediatric patients requiring occipitocervical fusion for treatment of deformity and/or instability at the CVJ. The use of intraoperative neuronavigation allows for safe placement of screws into C-0, especially when faced with a challenging patient in whom fixation to the occipital bone is not possible or is less than ideal. PMID:24206344

  19. Giant intradiploic epidermoid cyst of the occipital bone.

    PubMed

    Maiuri, F; Del Basso De Caro, M; D'Acunzi, G; Tortora, F; Esposito, F

    2004-01-01

    A rare case of giant intradiploic epidermoid cyst of the occipital bone with large intracranial extension in the posterior fossa is described. The lesion was discovered when the patient presented with headache and subcutaneous swelling in the occipital region, in the absence of signs of neurological involvement. CT scan showed extensive destruction of the occipital bone, mainly of the inner table, up to the foramen magnum. On MRI the lesion was hypointense in T(1) and hyperintense in T(2)-weighted images; signal inhomogeneity was due to cellular debris and cholesterol crystals. The enhancing rim due to the thickened dura confirmed the extradural location. Complete removal of the cyst was easily accomplished despite its large size. We found only 3 documented cases in the literature of giant intradiploic infratentorial epidermoid cysts, none of which was studied by MRI. The radiological features and differential diagnosis are discussed. PMID:14981574

  20. The vertical occipital fasciculus: A century of controversy resolved by in vivo measurements

    PubMed Central

    Yeatman, Jason D.; Weiner, Kevin S.; Pestilli, Franco; Rokem, Ariel; Mezer, Aviv; Wandell, Brian A.

    2014-01-01

    The vertical occipital fasciculus (VOF) is the only major fiber bundle connecting dorsolateral and ventrolateral visual cortex. Only a handful of studies have examined the anatomy of the VOF or its role in cognition in the living human brain. Here, we trace the contentious history of the VOF, beginning with its original discovery in monkey by Wernicke (1881) and in human by Obersteiner (1888), to its disappearance from the literature, and recent reemergence a century later. We introduce an algorithm to identify the VOF in vivo using diffusion-weighted imaging and tractography, and show that the VOF can be found in every hemisphere (n = 74). Quantitative T1 measurements demonstrate that tissue properties, such as myelination, in the VOF differ from neighboring white-matter tracts. The terminations of the VOF are in consistent positions relative to cortical folding patterns in the dorsal and ventral visual streams. Recent findings demonstrate that these same anatomical locations also mark cytoarchitectonic and functional transitions in dorsal and ventral visual cortex. We conclude that the VOF is likely to serve a unique role in the communication of signals between regions on the ventral surface that are important for the perception of visual categories (e.g., words, faces, bodies, etc.) and regions on the dorsal surface involved in the control of eye movements, attention, and motion perception. PMID:25404310

  1. Downstream targets of methyl CpG binding protein 2 and their abnormal expression in the frontal cortex of the human Rett syndrome brain

    Microsoft Academic Search

    Joanne H Gibson; Barry Slobedman; Harikrishnan KN; Sarah L Williamson; Dimitri Minchenko; Assam El-Osta; Joshua L Stern; John Christodoulou

    2010-01-01

    BACKGROUND: The Rett Syndrome (RTT) brain displays regional histopathology and volumetric reduction, with frontal cortex showing such abnormalities, whereas the occipital cortex is relatively less affected. RESULTS: Using microarrays and quantitative PCR, the mRNA expression profiles of these two neuroanatomical regions were compared in postmortem brain tissue from RTT patients and normal controls. A subset of genes was differentially expressed

  2. 3.2 "Lab-on-a-Chip" A Lab-on-a-Chip (LOC) device, also known as a micro-total-analytical system

    E-print Network

    shows an example of an LOC device that was tested on the International Space Station in 2007. Figure 28: LOC device tested on the International Space Station in 2007 At the heart of LOC devices are "chips

  3. iLOC: An invisible LOCalization Attack to Internet Threat Monitoring Systems

    E-print Network

    Xuan, Dong

    iLOC: An invisible LOCalization Attack to Internet Threat Monitoring Systems Xun Wang, Wei Yu (ITM) systems, a class of widely deployed facilities to characterize Internet threats, such as worm of the ITM system. We conduct extensive simulations on the iLOC attack using real-world traces. Our data

  4. Refractory headaches treated with bilateral occipital and temporal region stimulation

    PubMed Central

    Zach, Kelly J; Trentman, Terrence L; Zimmerman, Richard S; Dodick, David W

    2014-01-01

    Objectives To describe use of bilateral temporal and occipital stimulator leads for a refractory headache disorder. Materials and methods A 31-year-old female had a 10-year history of chronic, severe occipital and temporal region headaches. The patient underwent permanent implant of an occipital stimulator system that resulted in sustained, compete resolution of her occipital pain. However, she continued to suffer disabling (10/10) temporal region headaches and was bedbound most days of the week. Therefore, bilateral temporal stimulator leads were implanted and tunneled to her internal pulse generator. Results At 12-month follow-up, the patient enjoyed sustained improvement in her pain scores (8/10) and marked increase in her level of functioning. Taking into account increased activity level, she rated her overall improvement at 50%. Unfortunately, infection and erosion of her right temporal lead necessitated temporal stimulator removal. Conclusion Headache disorders may require stimulation of all painful cephalic regions. However, our success in this case must be considered in light of the technical challenges and expense of placing stimulator leads subcutaneously around the head and neck, including the risk of infection, lead breakage, erosion, and migration. PMID:24707189

  5. RESEARCH REPORT Occipital gamma activation during Vipassana meditation

    E-print Network

    Long-term Vipassana meditators sat in medi- tation vs. a control rest (mind-wandering) state for 21 minRESEARCH REPORT Occipital gamma activation during Vipassana meditation B. Rael Cahn · Arnaud in a counterbalanced design with spontaneous EEG recor- ded. Meditation state dynamics were measured with spec- tral

  6. RESEARCH REPORT Occipital gamma activation during Vipassana meditation

    E-print Network

    Delorme, Arnaud

    RESEARCH REPORT Occipital gamma activation during Vipassana meditation B. Rael Cahn · Arnaud. This article is published with open access at Springerlink.com Abstract Long-term Vipassana meditators sat in medi- tation vs. a control rest (mind-wandering) state for 21 min in a counterbalanced design

  7. Benign Occipital Epilepsies of Childhood: Clinical Features and Genetics

    ERIC Educational Resources Information Center

    Taylor, Isabella; Berkovic, Samuel F.; Kivity, Sara; Scheffer, Ingrid E.

    2008-01-01

    The early and late benign occipital epilepsies of childhood (BOEC) are described as two discrete electro-clinical syndromes, eponymously known as Panayiotopoulos and Gastaut syndromes. Our aim was to explore the clinical features, classification and clinical genetics of these syndromes using twin and multiplex family studies to determine whether…

  8. LncRNA loc285194 is a p53-regulated tumor suppressor

    PubMed Central

    Liu, Qian; Huang, Jianguo; Zhou, Nanjiang; Zhang, Ziqiang; Zhang, Ali; Lu, Zhaohui; Wu, Fangting; Mo, Yin-Yuan

    2013-01-01

    Protein-coding genes account for only a small part of the human genome, whereas the vast majority of transcripts make up the non-coding RNAs including long non-coding RNAs (lncRNAs). Accumulating evidence indicates that lncRNAs could play a critical role in regulation of cellular processes such as cell growth and apoptosis as well as cancer progression and metastasis. LncRNA loc285194 was previously shown to be within a tumor suppressor unit in osteosarcoma and to suppress tumor cell growth. However, it is unknown regarding the regulation of loc285194. Moreover, the underlying mechanism by which loc285194 functions as a potential tumor suppressor is elusive. In this study, we show that loc285194 is a p53 transcription target; ectopic expression of loc285194 inhibits tumor cell growth both in vitro and in vivo. Through deletion analysis, we identify an active region responsible for tumor cell growth inhibition within exon 4, which harbors two miR-211 binding sites. Importantly, this loc285194-mediated growth inhibition is in part due to specific suppression of miR-211. We further demonstrate a reciprocal repression between loc285194 and miR-211; in contrast to loc285194, miR-211 promotes cell growth. Finally, we detect downregulation of loc285194 in colon cancer specimens by quantitative PCR arrays and in situ hybridization of tissue microarrays. Together, these results suggest that loc285194 is a p53-regulated tumor suppressor, which acts in part through repression of miR-211. PMID:23558749

  9. Radiofrequency neurotomy for the treatment of third occipital headache

    PubMed Central

    Govind, J; King, W; Bailey, B; Bogduk, N

    2003-01-01

    Objective: To evaluate the efficacy of a revised technique of percutaneous radiofrequency neurotomy for third occipital headache. Methods: The revisions included using a large gauge electrode, ensuring minimum separation between the three electrode placements, and holding the electrode in place by hand. The revised technique was used to treat 51 nerves in 49 patients diagnosed as suffering from third occipital headache on the basis of controlled diagnostic blocks of the third occipital nerve. The criteria for successful outcome were complete relief of pain for at least 90 days associated with restoration of normal activities of daily living, and no use of drug treatment for the headache. Results: Of the 49 patients, 43 (88%) achieved a successful outcome. The median duration of relief in these patients was 297 days, with eight patients continuing to have ongoing relief. Fourteen patients underwent a repeat neurotomy to reinstate relief, with 12 (86%) achieving a successful outcome. The median duration of relief in these patients was 217 days, with six patients having ongoing relief. Side effects of the procedure were consistent with coagulation of the third occipital nerve and consisted of slight ataxia, numbness, and temporary dysaesthesia. No side effects required intervention, and they were tolerated by the patients in exchange for the relief of headache. Conclusions: Use of the revised procedure greatly improved the rather low success rate previously encountered with third occipital neurotomy. Although the relief of headache is limited in duration, it is profound and can be reinstated by repeat neurotomy. No other form of treatment has been validated for this common form of headache. PMID:12486273

  10. Language Networks in Anophthalmia: Maintained Hierarchy of Processing in "Visual" Cortex

    ERIC Educational Resources Information Center

    Watkins, Kate E.; Cowey, Alan; Alexander, Iona; Filippini, Nicola; Kennedy, James M.; Smith, Stephen M.; Ragge, Nicola; Bridge, Holly

    2012-01-01

    Imaging studies in blind subjects have consistently shown that sensory and cognitive tasks evoke activity in the occipital cortex, which is normally visual. The precise areas involved and degree of activation are dependent upon the cause and age of onset of blindness. Here, we investigated the cortical language network at rest and during an…

  11. Complex experience promotes capillary formation in young rat visual cortex.

    PubMed

    Black, J E; Sirevaag, A M; Greenough, W T

    1987-12-29

    The metabolic support of neural plasticity was examined by comparing cerebral vasculature of weanling rats reared in complex environments (EC) to littermates reared individually (IC) or socially in pairs (SC). EC rats have a thicker occipital cortex, more synaptic contacts per neuron and larger dendritic arbors compared to SC or IC rats, potentially increasing local metabolic demands on microvasculature. Capillaries of EC rats were closer together than those of SC or IC rats and potentially filled a greater fraction of cortex with blood. The closer capillary spacing in young EC rats suggests compensatory angiogenesis in response to increased metabolic demand. PMID:2450317

  12. Regional differences in neurotrophin availability regulate selective expression of VGF in the developing limbic cortex.

    PubMed

    Eagleson, K L; Fairfull, L D; Salton, S R; Levitt, P

    2001-12-01

    Gene and protein expression patterns in the cerebral cortex are complex and often change spatially and temporally through development. The signals that regulate these patterns are primarily unknown. In the present study, we focus on the regulation of VGF expression, which is limited to limbic cortical areas early in development but later expands into sensory and motor areas. We isolated neurons from embryonic day 17 rat cortex and demonstrate that the profile of VGF expression in perirhinal (expressing) and occipital (nonexpressing) populations in vitro is similar to that in the perinatal cortex in vivo. The addition of neutralizing neurotrophin antibodies indicates that endogenous brain-derived neurotrophic factor (BDNF) is necessary for the normal complement of VGF-expressing neurons in the perirhinal cortex, although endogenous neurotrophin-3 (NT-3) regulates the expression of VGF in a subpopulation of cells. ELISA analysis demonstrates that there is significantly more BDNF present in the perirhinal cortex compared with the occipital cortex in the perinatal period. However, the total amount of NT-3 is similar between the two regions and, moreover, there is considerably more NT-3 than BDNF in both areas, a finding seemingly in conflict with regional VGF expression. Quantification of the extracellular levels of neurotrophins in perirhinal and occipital cultures using ELISA in situ analysis indicates that perirhinal neurons release significantly more BDNF than the occipital population. Furthermore, the amount of NT-3 released by the perirhinal neurons is significantly less than the amount of BDNF. Local injection of BDNF in vivo into a normally negative VGF region results in robust ectopic expression of VGF. These data suggest that the local availability of specific neurotrophins for receptor occupation, rather than the total amount of neurotrophin, is a critical parameter in determining the selective expression of VGF in the developing limbic cortex. PMID:11717365

  13. The Involvement of Occipital and Inferior Frontal Cortex in the Phonological Learning of Chinese Characters

    ERIC Educational Resources Information Center

    Deng, Yuan; Chou, Tai-li; Ding, Guo-sheng; Peng, Dan-ling; Booth, James R.

    2011-01-01

    Neural changes related to the learning of the pronunciation of Chinese characters in English speakers were examined using fMRI. We examined the item-specific learning effects for trained characters and the generalization of phonetic knowledge to novel transfer characters that shared a phonetic radical (part of a character that gives a clue to the…

  14. Atlantoaxial Chordoma in Two Patients with Occipital Neuralgia and Cervicalgia

    PubMed Central

    Kim, Won Seop; Park, Jong Taek; Lee, Young Bok; Park, Woo Young

    2014-01-01

    Chordoma arises from cellular remnants of the notochord. It is the most common primary malignancy of the spine in adults. Approximately 50% of chordomas arise from the sacrococcygeal area with other areas of the spine giving rise to another 15% of chordomas. Following complete resection, patients can expect a 5-year survival rate of 85%. Chordoma has a recurrence rate of 40%, which leads to a less favorable prognosis. Here, we report two cases of chordoma presenting with occipital neuralgia and cervicalgia. The first patient presented with a C1–C2 chordoma. He rejected surgical intervention and ultimately died of respiratory failure. The second patient had an atlantoaxial chordoma and underwent surgery because of continued occipital neuralgia and cervicalgia despite nerve block. This patient has remained symptom-free since his operation. The presented cases show that the patients’ willingness to participate in treatment can lead to appropriate and aggressive management of cancer pain, resulting in better outcomes in cancer treatment.

  15. Atypical evolution in childhood epilepsy with occipital paroxysms (Panayiotopoulos type).

    PubMed

    Caraballo, R H; Astorino, F; Cersósimo, R; Soprano, A M; Fejerman, N

    2001-09-01

    We report, on two, school-age girls with clinical and electroencephalographic features of early onset childhood epilepsy with occipital paroxysms (CEOP) of the "Panayiotopoulos type" that showed atypical evolution. Neurological examination and brain imaging were normal in both. One child presented at age 2.5 years episodes of oculocephalic deviation, and ictal vomiting during nocturnal sleep. The EEG showed left occipital spikes during wakefulness and sleep. One year later, frequent inhibitory seizures appeared in the lower limbs causing, "pseudoataxic gait". At the same time she presented with behavioral disturbances and aphasia. EEG showed bilateral spike-waves while awake and continuous spike-waves during slow sleep (CSWSS). After switching AEDs to benzodiazepines, control of seizures along with improvement of behavior, and partial restoration of cognitive functions were achieved. The CSWSS disappeared and the last EEG at age 8 years only showed only isolated right occipital spikes. The other girl had a personal and familial history of febrile seizures. At 4 years of age she presented the first non-febrile seizures during sleep, with oculocephalic deviation and ictal vomiting, followed by a generalized tonic-clonic seizure. Partial control of seizures was obtained with antiepileptic drugs. At age 7, the child began to have weekly episodes of oculocephalic version, occasionally with secondary generalization. Repeated inhibitory seizures and absences also appeared. EEG showed frequent bilateral spikes occupying predominantly the posterior regions while awake, and CSWSS. At 7.5 years the same electro-clinical picture persisted. Ethosuximide was added to sodium valproate and clobazam. Fifteen days later, the seizures disappeared and the EEG showed less frequent bilateral occipital spikes. She is now 9 years old and she has been seizure-free for 18 months. Her present neuropsychological profile shows mild mental retardation. The two children with typical electroclinical features of "Panayiotopoulos Type" CEOP developed an atypical evolution which, to our knowledge, has not been described previously. PMID:11679309

  16. A genetic and anthropological study of atlanto-occipital fusion

    Microsoft Academic Search

    A. K. Kalla; S. Khanna; I. P. Singh; S. Sharma; R. Schnobel; F. Vogel

    1989-01-01

    Families of 20 probands with atlanto-occipital fusion were studied, and the neurological complications in these patients described. In X-ray studies of 115 close relatives, 4 additional cases (3.5%) with the same anomaly were detected. In a comparison of adult patients with closely related age- and sex-matched controls, all anthropological measurements except length and breadth of the head tended to be

  17. Non-traumatic posterior atlanto-occipital joint dislocation

    Microsoft Academic Search

    Yasuhiko Takechi; Haku Iizuka; Yasunori Sorimachi; Tsuyoshi Ara; Masahiro Nishinome; Kenji Takagishi

    2011-01-01

    This report presents a case of non-traumatic posterior atlanto-occipital dislocation. A 36-year-old female was referred with\\u000a a history of numbness of the extremities, vertigo and neck pain for 1 year. The patient had no history of trauma. The axial\\u000a rotation of range of motion of the cervical spine was severely restricted. A lateral cervical radiograph in the neutral position\\u000a demonstrated a

  18. Biomechanical and morphometric evaluation of occipital condyle for occipitocervical segmental fixation.

    PubMed

    Hong, Jae Taek; Takigawa, Tomoyuki; Sugisaki, Keizo; Espinoza Orías, Alejandro A; Inoue, Nozomu; An, Howard S

    2011-01-01

    Two recent novel techniques of occipital fixation are the occipitoatlantal (C0-C1) transarticular screw technique and the direct occipital condyle screw technique. The present study evaluated and compared the biomechanical stability of the direct occipital condyle screw and C0-C1 transarticular screw with the established method for craniocervical spine fixation using the midline occipital keel screw and C1 lateral mass screw. Morphometric evaluation of the occipital condyle and the hypoglossal canal was performed to avoid hypoglossal nerve injury during the screw placement. Thirteen recently frozen cadaveric specimens were used. The occipital condyle anatomy and the hypoglossal canal dimension were measured using reconstructed computed tomography images. Insertion torque and pullout strength were evaluated to compare the midline occipital keel screw, C0-C1 transarticular screw, C1 lateral mass screw, and direct occipital condyle screw. The dimensions of the occipital condyle allow use of a 3.5 or 4.0-mm diameter screw. Mean pullout strength was 1619.6 N for the midline occipital keel screw, 870.7 N for the C0-C1 transarticular screw, 707.0 N for the C1 lateral mass screw, and 431.7 N for the direct occipital condyle screw. Mean insertion torque was 0.55 Nm for the midline occipital keel screw, 0.32 Nm for the C0-C1 transarticular screw, 0.14 Nm for the C1 lateral mass screw, and 0.11 Nm for the direct occipital condyle screw. The condylar anatomy allows direct insertion of the occipital condyle screw and C0-C1 transarticular screw. These techniques are suitable options for the treatment of craniovertebral junction instabilities in selected patients. PMID:22027245

  19. Visual disturbances representing occipital lobe epilepsy in patients with cerebral calcifications and coeliac disease: a case series

    Microsoft Academic Search

    M Pfaender; W J D’Souza; N Trost; L Litewka; M Paine; M Cook

    2004-01-01

    Paroxysmal visual manifestations may represent epileptic seizures arising from the occipital lobe. In coeliac disease (CD) bilateral occipital calcifications and seizure semiology consistent with an occipital origin have been described, primarily in Mediterranean countries. By reporting three adult patients from an Australian outpatient clinic with visual disturbances, occipital cerebral calcifications, and CD, this study seeks to emphasise that CD should

  20. Occipital and orbitofrontal hemodynamics during naturally paced reading: an fNIRS study.

    PubMed

    Hofmann, Markus J; Dambacher, Michael; Jacobs, Arthur M; Kliegl, Reinhold; Radach, Ralph; Kuchinke, Lars; Plichta, Michael M; Fallgatter, Andreas J; Herrmann, Martin J

    2014-07-01

    Humans typically read at incredibly fast rates, because they predict likely occurring words from a given context. Here, we used functional near-infrared spectroscopy (fNIRS) to track the ultra-rapid hemodynamic responses of words presented every 280 ms in a naturally paced sentence context. We found a lower occipital deoxygenation to unpredictable than to predictable words. The greater hemodynamic responses to unexpected words suggest that the visual features of expected words have been pre-activated previous to stimulus presentation. Second, we tested opposing theoretical proposals about the role of the medial orbitofrontal cortex (OFC): Either OFC may respond to the breach of expectation; or OFC is activated when the present stimulus matches the prediction. A significant interaction between word frequency and predictability indicated OFC responses to breaches of expectation for low- but not for high-frequency words: OFC is sensitive to both, bottom-up processing as mediated by word frequency, as well as top-down predictions. Particularly, when a rare word is unpredictable, OFC becomes active. Finally, we discuss how a high temporal resolution can help future studies to disentangle the hemodynamic responses of single trials in such an ultra-rapid event succession as naturally paced reading. PMID:24642288

  1. Peritrigonal and temporo-occipital heterotopia with corpus callosum and cerebellar dysgenesis

    PubMed Central

    Pisano, Tiziana; Barkovich, A. James; Leventer, Richard J.; Squier, Waney; Scheffer, Ingrid E.; Parrini, Elena; Blaser, Susan; Marini, Carla; Robertson, Stephen; Tortorella, Gaetano; Rosenow, Felix; Thomas, Pierre; McGillivray, George; Andermann, Eva; Andermann, Frederick; Berkovic, Samuel F.; Dobyns, William B.

    2012-01-01

    Objective: To describe a homogeneous subtype of periventricular nodular heterotopia (PNH) as part of a newly defined malformation complex. Methods: Observational study including review of brain MRI and clinical findings of a cohort of 50 patients with PNH in the temporo-occipital horns and trigones, mutation analysis of the FLNA gene, and anatomopathologic study of a fetal brain. Results: There were 28 females and 22 males. All were sporadic with the exception of an affected mother and son. Epilepsy occurred in 62%, cerebellar signs in 56%, cognitive impairment in 56%, and autism in 12%. Seventy percent were referred within the 3rd year of life. Imaging revealed a normal cerebral cortex in 76% and abnormal cortical folding in 24%. In all patients the hippocampi were under-rotated and in 10% they merged with the heterotopia. Cerebellar dysgenesis was observed in 84% and a hypoplastic corpus callosum in 60%. There was no gender bias or uneven gender distribution of clinical and anatomic severity. No mutations of FLNA occurred in 33 individuals examined. Heterotopia in the fetal brain revealed cytoarchitectonic characteristics similar to those associated with FLNA mutations; cortical pathology was not typical of polymicrogyria. Cerebellar involvement was more severe and the hippocampi appeared simple and under-rotated. Conclusions: This series delineates a malformation complex in which PNH in the trigones and occipito-temporal horns is associated with hippocampal, corpus callosum, and cerebellar dysgenesis. This subtype of PNH is distinct from classic PNH caused by FLNA mutations. PMID:22914838

  2. Responses to interocular disparity correlation in the human cerebral cortex

    PubMed Central

    Ip, Ifan Betina; Minini, Loredana; Dow, James; Parker, Andrew J; Bridge, Holly

    2014-01-01

    Purpose Perceiving binocular depth relies on the ability of our visual system to precisely match corresponding features in the left and right eyes. Yet how the human brain extracts interocular disparity correlation is poorly understood. Methods We used functional magnetic resonance imaging (fMRI) to characterize brain regions involved in processing interocular disparity correlation. By varying the amount of interocular correlation of a disparity-defined random-dot-stereogram, we concomitantly controlled the perception of binocular depth and measured the percent Blood-Oxygenation-Level-Dependent (%BOLD)-signal in multiple regions-of-interest in the human occipital cortex and along the intra-parietal sulcus. Results A linear support vector machine classification analysis applied to cortical responses showed patterns of activation that represented different disparity correlation levels within regions-of-interest in the visual cortex. These also revealed a positive trend between the difference in disparity correlation and classification accuracy in V1, V3 and lateral occipital cortex. Classifier performance was significantly related to behavioural performance in dorsal visual area V3. Cortical responses to random-dot-stereogram stimuli were greater in the right compared to the left hemisphere. Conclusions Our results show that multiple regions in the cerebral cortex are sensitive to changes in interocular disparity correlation, and that dorsal area V3 may play an important role in the early transformation of binocular disparity to depth perception. PMID:24588533

  3. Survivor of a traumatic atlanto-occipital dislocation.

    PubMed

    Ehlinger, M; Charles, Y-P; Adam, P; Bierry, G; Dosch, J-C; Steib, J-P; Bonnomet, F

    2011-05-01

    Atlanto-occipital dislocation is a devastating ligamentous injury that most often turns fatal. However, because of on-site resuscitation improvements, the emergency teams are increasingly dealing with this condition. We report a rare case of atlanto-occipital dislocation (AOD) in a surviving patient with more than one-year follow-up. The mechanism of injury appears to be an extreme hyperextension applied to the head. This injury occurs more frequently in children since they are anatomically predisposed (flat articulation between the occiput and the atlas, increased ligamentous laxity). The diagnosis should be suggested by severe neurological injury after high trauma but also post-traumatic cardiorespiratory deficit. There have been reports of atlanto-occipital dilocations without neurologic impairment. A radiographic examination must be performed and lateral cervical radiographs should be acquired. However, additional imaging with CT or MRI may be required to aid diagnosis of AOD in cases in which radiographic findings are equivocal. Once the diagnosis of AOD has been confirmed, an anatomical classification should be made according to the magnitude of displacement. Fatal lesions are of neurological and vascular origin and some authors advocate the systematic use of angiography. Consensus regarding the management of AOD in adults has been achieved. Occipito-cervical arthrodesis is the recommended treatment option. We advocate a two-stage surgery: the patient is initially fitted with a halo vest then occipitocervical fusion is performed. Surgical treatment should be combined with cardiorespiratory management. The emergency teams should get familiar with this injury since they will be increasingly confronted to it. Early recognition and standard appropriate management is essential to avoid delayed treatment and complications. PMID:21273154

  4. Functional 5HT receptors in human occipital artery

    Microsoft Academic Search

    Raphaela Verheggen; Andreas Meier; Inga Werner; Andreas Wienekamp; Thomas Kruschat; Trond Brattelid; FinnOlav Levy; Alberto Kaumann

    2004-01-01

    5-HT receptors were studied in human occipital arteries, obtained from patients during neurosurgery. We detected mRNA for the following receptors (incidence): 5-HT 1B (14\\/18), 5-HT 1D (15\\/18), 5-HT 2A (16\\/18), 5-HT 2B (8\\/8), 5-HT 4(a) (13\\/18), 5-HT 4(b) (5\\/18), 5-HT 4(g) (7\\/18), 5-HT 4(i) (1\\/18), 5-HT 7(a\\/b) (10\\/18) and 5-HT 7(d) (12\\/18). 5-HT contracted and relaxed arterial rings at low

  5. Occipital neuralgia after hair transplantation and its treatment.

    PubMed

    Siefferman, Jason; Khelemsky, Yury

    2015-01-01

    While undergoing full thickness tissue harvest from the posterior scalp, a 72-year-old man experienced immediate severe pain in the right occiput and was unable to complete the procedure. The pain was constant "sharp" and "shocking" with numbness in the distribution of the lesser occipital nerve, exacerbated by physical activity, and local anesthetic blocks provided temporary complete relief. After numerous treatments over several years, including oral analgesics, botulinum toxin injections, and acupuncture, proved ineffective, pulsed radiofrequency neuromodulation provided greater than 80% relief for 5 months. PMID:25688308

  6. Occipital Neuralgia after Hair Transplantation and Its Treatment

    PubMed Central

    Siefferman, Jason; Khelemsky, Yury

    2015-01-01

    While undergoing full thickness tissue harvest from the posterior scalp, a 72-year-old man experienced immediate severe pain in the right occiput and was unable to complete the procedure. The pain was constant “sharp” and “shocking” with numbness in the distribution of the lesser occipital nerve, exacerbated by physical activity, and local anesthetic blocks provided temporary complete relief. After numerous treatments over several years, including oral analgesics, botulinum toxin injections, and acupuncture, proved ineffective, pulsed radiofrequency neuromodulation provided greater than 80% relief for 5 months. PMID:25688308

  7. Occipital inter-hemispheric approach for lateral ventricular trigone meningioma

    Microsoft Academic Search

    Takafumi Nishizaki; Norio Ikeda; Shigeki Nakano; Tomomi Okamura; Seisho Abiko

    2009-01-01

    Objective  The optimal surgical approach for a trigone meningioma is still controversial. Here, we report two patients with trigone meningioma\\u000a treated successfully via an occipital inter-hemispheric and trans-cortical approach in the lateral semi-prone position.\\u000a \\u000a \\u000a \\u000a Clinical presentation  A 53-year-old woman was admitted to a local hospital with sudden transient dizziness and vomiting. The CT brain scan demonstrated\\u000a a right intra-ventricular tumour. She was

  8. Occipital condyle fractures: incidence and clinical follow-up at a level 1 trauma centre

    Microsoft Academic Search

    Gregory M. Malham; Helen M. Ackland; Rachel Jones; Owen D. Williamson; Dinesh K. Varma

    2009-01-01

    The purpose of the study was to investigate the incidence, management, and outcomes of occipital condyle fractures at a level\\u000a 1 trauma center. Blunt trauma patients with occipital condyle fracture admitted to a level 1 trauma center over a 3-year period\\u000a were identified. Prospective clinical and functional follow-up was undertaken, including further radiographic imaging. The\\u000a incidence of occipital condyle fracture

  9. The Intramuscular Course of the Greater Occipital Nerve: Novel Findings with Potential Implications for Operative Interventions and Occipital Neuralgia

    PubMed Central

    Tubbs, R. Shane; Watanabe, Koichi; Loukas, Marios; Cohen-Gadol, Aaron A.

    2014-01-01

    Background: A better understanding of the etiologies of occipital neuralgia would help the clinician treat patients with this debilitating condition. Since few studies have examined the muscular course of the greater occipital nerve (GON), this study was performed. Methods: Thirty adult cadaveric sides underwent dissection of the posterior occiput with special attention to the intramuscular course of the GON. Nerves were typed based on their muscular course. Results: The GON traveled through the trapezius (type I; n = 5, 16.7%) or its aponeurosis (type II; n = 15, 83.3%) to become subcutaneous. Variations in the subtrapezius muscular course were found in 10 (33%) sides. In two (6.7%) sides, the GON traveled through the lower edge of the inferior capitis oblique muscle (subtype a). On five (16.7%) sides, the GON coursed through a tendinous band of the semispinalis capitis, not through its muscular fibers (subtype b). On three (10%) sides the GON bypassed the semispinalis capitis muscle to travel between its most medial fibers and the nuchal ligament (subtype c). For subtypes, eight were type II courses (through the aponeurosis of the trapezius), and two were type I courses (through the trapezius muscle). The authors identified two type IIa courses, four type IIb courses, and two type IIc courses. Type I courses included one type Ib and one type Ic courses. Conclusions: Variations in the muscular course of the GON were common. Future studies correlating these findings with the anatomy in patients with occipital neuralgia may elucidate nerve courses vulnerable to nerve compression. This enhanced classification scheme describes the morphology in this region and allows more specific communications about GON variations. PMID:25422783

  10. Reduced ?-aminobutyric acid in occipital and anterior cingulate cortices in primary insomnia: a link to major depressive disorder?

    PubMed

    Plante, David T; Jensen, J Eric; Schoerning, Laura; Winkelman, John W

    2012-05-01

    Insomnia is closely related to major depressive disorder (MDD) both cross-sectionally and longitudinally, and as such, offers potential opportunities to refine our understanding of the neurobiology of both sleep and mood disorders. Clinical and basic science data suggest a role for reduced ?-aminobutyric acid (GABA) in both MDD and primary insomnia (PI). Here, we have utilized single-voxel proton magnetic spectroscopy (1H-MRS) at 4 Tesla to examine GABA relative to total creatine (GABA/Cr) in the occipital cortex (OC), anterior cingulate cortex (ACC), and thalamus in 20 non-medicated adults with PI (12 women) and 20 age- and sex-matched healthy sleeper comparison subjects. PI subjects had significantly lower GABA/Cr in the OC (p=0.0005) and ACC (p=0.03) compared with healthy sleepers. There was no significant difference in thalamic GABA/Cr between groups. After correction for multiple comparisons, GABA/Cr did not correlate significantly with insomnia severity measures among PI subjects. This study is the first to demonstrate regional reductions of GABA in PI in the OC and ACC. Reductions in GABA in similar brain regions in MDD using 1H-MRS suggest a common reduction in cortical GABA among PI and mood disorders. PMID:22318195

  11. Intractable Occipital Neuralgia Caused by an Entrapment in the Semispinalis Capitis

    PubMed Central

    Kim, Deok-ryeong; Lee, Sang-won

    2013-01-01

    Occipital neuralgia is a rare pain syndrome characterized by periodic lancinating pain involving the occipital nerve complex. We present a unique case of entrapment of the greater occipital nerve (GON) within the semispinalis capitis, which was thought to be the cause of occipital neuralgia. A 66-year-old woman with refractory left occipital neuralgia revealed an abnormally low-loop of the left posterior inferior cerebellar artery on the magnetic resonance imaging, suggesting possible vascular compression of the upper cervical roots. During exploration, however, the GON was found to be entrapped at the perforation site of the semispinalis capitis. There was no other compression of the GON or of C1 and C2 dorsal roots in their intracranial course. Postoperatively, the patient experienced almost complete relief of typical neuralgic pain. Although occipital neuralgia has been reported to occur by stretching of the GON by inferior oblique muscle or C1-C2 arthrosis, peripheral compression in the transmuscular course of the GON in the semispinalis capitis as a cause of refractory occipital neuralgia has not been reported and this should be considered when assessing surgical options for refractory occipital neuralgia. PMID:24278663

  12. Occipital Condyle Syndrome in a Young Male: A Rare Presentation of Cranio-Vertebral Tuberculosis

    PubMed Central

    Yogesh, Patidar; Vinod, Puri; A, Khwaja Geeta

    2014-01-01

    Occipital condyle syndrome (OCS) is a rare syndrome characterized by severe, unilateral, occipital headache and ipsilateral 12th nerve palsy. Tumors are a common cause of OCS. Inflammatory lesions causing OCS is however rare. We describe a young male with OCS as the only manifestation of cranio-vertebral tuberculosis. PMID:25664279

  13. Algorithmic, LOCS and HOCS (chemistry) exam questions: performance and attitudes of college students

    NASA Astrophysics Data System (ADS)

    Zoller, Uri

    2002-02-01

    The performance of freshmen biology and physics-mathematics majors and chemistry majors as well as pre- and in-service chemistry teachers in two Israeli universities on algorithmic (ALG), lower-order cognitive skills (LOCS), and higher-order cognitive skills (HOCS) chemistry exam questions were studied. The driving force for the study was an interest in moving science and chemistry instruction from an algorithmic and factual recall orientation dominated by LOCS, to a decision-making, problem-solving and critical system thinking approach, dominated by HOCS. College students' responses to the specially designed ALG, LOCS and HOCS chemistry exam questions were scored and analysed for differences and correlation between the performance means within and across universities by the questions' category. This was followed by a combined student interview - 'speaking aloud' problem solving session for assessing the thinking processes involved in solving these types of questions and the students' attitudes towards them. The main findings were: (1) students in both universities performed consistently in each of the three categories in the order of ALG > LOCS > HOCS; their 'ideological' preference, was HOCS > algorithmic/LOCS, - referred to as 'computational questions', but their pragmatic preference was the reverse; (2) success on algorithmic/LOCS does not imply success on HOCS questions; algorithmic questions constitute a category on its own as far as students success in solving them is concerned. Our study and its results support the effort being made, worldwide, to integrate HOCS-fostering teaching and assessment strategies and, to develop HOCS-oriented science-technology-environment-society (STES)-type curricula within science and chemistry education.

  14. Pitfalls in the Management of Atlanto-Occipital Dislocation

    PubMed Central

    Yasuda, Muneyoshi; Joko, Masahioro; Takeuchi, Mikinobu; Niwa, Aichi; Takayasu, Masakazu

    2015-01-01

    Atlanto-occipital dislocation (AOD) is rarely seen in clinic because it is characteristically immediately fatal. With recent progress in the pre-hospital care, an increasing number of AOD survivors have been reported. However, because the pathophysiology of AOD is not clearly understood yet, the appropriate strategy for the initial management remains still unclear. We report a case of successful AOD treatment and describe important points in the management of this condition. It is important to note that abducens nerve palsy is a warning sign of AOD and that AOD can result in a life-threatening distortion of the arteries and the brain stem. We recommend the application of a halo vest to protect the patient's neural and vascular competence as the immediate initial step in the treatment of AOD. Horn's grading system is useful in assessing indications for surgery. Finally, when performing posterior fixation, C2 should be included because of the anatomy of the ligamentous architecture.

  15. Occipital nerve stimulation in a patient with an intractable chronic headache -A case report-

    PubMed Central

    Shin, Jae Hyuck; Jang, In Ki; Kim, Jae-Hun; Park, Soo Young; Lee, Sang Chul

    2011-01-01

    Occipital nerve stimulation (ONS) is a form of peripheral nerve stimulation used to treat refractory headaches. The trial of ONS was carried with the midline incision C1-2 level, inserted electrical lead subcutaneously to oblique and cephalad direction followed by trajectory of blunt dissection. We used 8 pole electrical lead to cover lesser occipital nerve, greater occipital nerve, third occipital nerve and great auricular nerve. We anchored the lead at the midline insertion site after confirming the stimulation of the patient. And then we looped and tightened the lead loosely, connected the lead and the extension under right supraspinatus muscle region. After 1 week trial period, we performed the permanent implantation of occipital nerve stimulator. We inserted internal pulse generator under a pocket located at right infraclavicular region. The VAS score dropped from 8/10 to 1-2/10. No serious complications were detected during 1 month follow-up. PMID:21602983

  16. [Two-way deficit between phonological and arabic representation of numbers after left parieto-occipital hemorrhage].

    PubMed

    Hirayama, Kazumi; Endo, Keiko; Okada, Kazue; Yamadori, Atsushi; Mori, Etsuro

    2011-05-01

    A 52-year-old right-handed man developed a deficit of two-way transcoding between phonological and Arabic representations of numbers after cerebral hemorrhage in the left occipital lobe, intraparietal sulcus, and the surrounding of inferior parietal lobule. He showed right hemianopia, mild Wernicke's aphasia, agraphia, and phonological dyslexia. Calculation, comparison between numbers and comprehension of arithmetic signs were almost preserved. Retrieval of the mnemonic rhymes for the multiplication table (kuku) was moderately compromised. He showed good performance in the following tasks: selecting coins corresponding to the number orally designated by the experimenter, reporting orally the amount of arranged coins, selecting coins according to written amount, indicating the amount of arranged coins by writing numbers, and choosing the amount of arranged coins from several alternatives of written numbers. Thus, encoding the phonological and visual representations of numbers from the meanings as well as decoding from these 2 representations into their meanings were preserved. However, he showed grave difficulty in dictation of numbers, in choosing the verbally indicated numbers from among a set of written numbers, and in reading aloud a number. Thus, two-way impairment of association between phonological and visual representations of numbers was confirmed. Regarding other categories of nouns, marked deterioration was detected only in dictation and writing the names of indicated objects. We taught him a strategy of imaging the coins when he transcoded from Arabic representation of numbers to phonological representation and vice versa. This strategy improved his performance to some extent. These results suggest that there is a direct, bi-directional transcoding route between phonological and visual representations of numbers, which is not mediated by semantic representation. This route can be impaired by a lesion located in the left parieto-occipital cortex. PMID:21515930

  17. PAPER www.rsc.org/loc | Lab on a Chip Laser-induced cavitation based micropump

    E-print Network

    Ohl, Claus-Dieter

    PAPER www.rsc.org/loc | Lab on a Chip Laser-induced cavitation based micropump Rory Dijkinka as versatile and robust pumping techniques. Here, we present a cavitation based technique, which is able cavitation event is created by focusing a laser pulse in a conventional PDMS microfluidic chip close

  18. A variant of mitochondrial protein LOC387715/ ARMS2, not HTRA1, is strongly associated

    E-print Network

    Abecasis, Goncalo

    of *Ophthalmology and Visual Sciences, Biological Chemistry, Biostatistics, and ¶Human Genetics, University, and approved August 7, 2007 (received for review April 30, 2007) Genetic variants at chromosomes 1q31-32 and 10 homozygotes. The rs10490924 SNP results in nonsynonymous A69S alteration in the predicted protein LOC387715

  19. LEARNING AND ORGANIZATIONAL CHANGE (LOC) The Learning and Organizational Change concentration helps you explore how

    E-print Network

    Shahriar, Selim

    , the concentration draws upon innovations in learning sciences and theories of organizational behavior to teach youLEARNING AND ORGANIZATIONAL CHANGE (LOC) CURRICULUM The Learning and Organizational Change change through learning and organizational design. The assessment, design and implementation of knowledge

  20. ID/LOC Separation Network Architecture for Mobility Support in Future Internet

    E-print Network

    ID/LOC Separation Network Architecture for Mobility Support in Future Internet Nakjung Choi, Taewan Internet scale. We extend the LISP+ALT architecture to provide roaming for global mobility and take network architecture for mobility support in future Internet in Section III by simple analysis. Finally

  1. Changes in Cerebral Cortex of Children Treated for Medulloblastoma

    SciTech Connect

    Liu, Arthur K. [Harvard Combined Radiation Oncology Program, Harvard Medical School, Boston, MA (United States)]. E-mail: aliu1@partners.org; Marcus, Karen J. [Department of Radiation Oncology, Children's Hospital Boston, Harvard Medical School, Boston, MA (United States); Department of Radiation Oncology, Dana Farber Cancer Institute, Harvard Medical School, Boston, MA (United States); Department of Radiation Oncology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA (United States); Fischl, Bruce [Athinoula A. Martinos Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA (United States); Department of Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Division of Health Sciences and Technology, Cambridge, MA (United States); Grant, P. Ellen [Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA (United States); Young Poussaint, Tina [Department of Radiology, Children's Hospital Boston, Harvard Medical School, Boston, MA (United States); Rivkin, Michael J. [Departments of Neurology, Psychiatry, and Radiology, Children's Hospital Boston, Harvard Medical School, Boston, MA (United States); Davis, Peter [Departments of Neurology, Psychiatry, and Radiology, Children's Hospital Boston, Harvard Medical School, Boston, MA (United States); Tarbell, Nancy J. [Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA (United States); Yock, Torunn I. [Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA (United States)

    2007-07-15

    Purpose: Children with medulloblastoma undergo surgery, radiotherapy, and chemotherapy. After treatment, these children have numerous structural abnormalities. Using high-resolution magnetic resonance imaging, we measured the thickness of the cerebral cortex in a group of medulloblastoma patients and a group of normally developing children. Methods and Materials: We obtained magnetic resonance imaging scans and measured the cortical thickness in 9 children after treatment of medulloblastoma. The measurements from these children were compared with the measurements from age- and gender-matched normally developing children previously scanned. For additional comparison, the pattern of thickness change was compared with the cortical thickness maps from a larger group of 65 normally developing children. Results: In the left hemisphere, relatively thinner cortex was found in the perirolandic region and the parieto-occipital lobe. In the right hemisphere, relatively thinner cortex was found in the parietal lobe, posterior superior temporal gyrus, and lateral temporal lobe. These regions of cortical thinning overlapped with the regions of cortex that undergo normal age-related thinning. Conclusion: The spatial distribution of cortical thinning suggested that the areas of cortex that are undergoing development are more sensitive to the effects of treatment of medulloblastoma. Such quantitative methods may improve our understanding of the biologic effects that treatment has on the cerebral development and their neuropsychological implications.

  2. Parieto-occipital encephalomalacia in children; clinical and electrophysiological features of twenty-seven cases

    PubMed Central

    Karao?lu, Pakize; Polat, Ay?e ?pek; Yi?, Uluç; H?z, Semra

    2015-01-01

    Context: Brain injuries occurring at a particular time may cause damages in well-defined regions of brain. Perinatal hypoxic ischemic encephalopathy and hypoglycemia are some of the most common types of brain injuries. Neonatal hypoglycemia can cause abnormal myelination in parietal and occipital lobes resulting in parieto-occipital encephalomalacia. There is a small number of studies about clinical and electroencephalographic (EEG) features of children with parieto-occipital encephalomalacia. They might have important neurologic sequelae such as cortical visual loss, seizures, and psychomotor retardation. Aims: We aimed to evaluate the causes of parieto-occipital encephalomalacia and evaluate the clinical and electrophysiological features of children with parieto-occipital encephalomalacia. Settings and Design: We evaluated clinical features and EEGs of 27 children with parieto-occipital encephalomalacia. Statistical Analysis Used: Descriptive statistics were used. Results: Hospitalization during the neonatal period was the most common cause (88.9%) of parieto-occipital brain injury. Eleven patients (40.7%) had a history of neonatal hypoglycemia. Twenty-three patients (85.2%) had epilepsy and nine of the epileptic patients (39%) had refractory seizures. Most of the patients had bilateral (50%) epileptic discharges originating from temporal, parietal, and occipital lobes (56.2%). However, some patients had frontal sharp waves and some had continuous spike and wave discharges during sleep. Visual abnormalities were evident in 15 (55.6%) patients. Twenty-two (81.5%) had psychomotor retardation. Fine motor skills, social contact and language development were impaired more than gross motor skills. Conclusions: In our study, most of the patients with parieto-occipital encephalomalacia had an eventful perinatal history. Epilepsy, psychomotor retardation, and visual problems were common neurologic complications.

  3. Visual manifestations of occipital lobe infarction in three patients on a geriatric psychiatry unit.

    PubMed

    La Mancusa, J C; Cole, A R

    1988-01-01

    The authors present three cases of hospitalized patients on a geriatric psychiatry floor who were found to have previously undiagnosed occipital lobe infarctions associated with visual manifestations. The manifestations discussed are visual field defects, visual hallucinations, and color anomia. The incidence of undiagnosed occipital lobe infarctions and the contribution of these infarctions to visual perception changes in this patient population are unknown. The authors suggest that for patients who present with visual perception changes, a high index of suspicion for occipital lobe infarction should be maintained. Careful visual field testing is an essential part of the admitting work-up for hospitalized geriatric patients. PMID:3252891

  4. Cervical Myelopathy Secondary to Atlanto-occipital Assimilation: The Usefulness of the Simple Decompressive Surgery

    PubMed Central

    Kim, Kang Rae; Kim, Young Zoon; Cho, Yong Woon; Kim, Joon Soo; Kim, Kyu Hong; Lee, In Chang

    2013-01-01

    Atlanto-occipital assimilation is one of the most common osseous anomalies observed at the craniocervical junction. Most patients with atlas assimilation show no symptom, but some have neurological problems such as myelopathy that may require surgical treatment. Occipitocervical fusion may be required if atlato-occipital assimilation is accompanied by occipito-axial instability. However, in cases of symptomatic atlas assimilation with minor cord compression without instability, simple decompressive surgery may be the treatment modality. This report describes a case of successful treatment of a patient with myelopathy secondary to atlanto-occipital assimilation without instability, using posterior simple decompressive surgery. PMID:24757486

  5. Cervical Myelopathy Secondary to Atlanto-occipital Assimilation: The Usefulness of the Simple Decompressive Surgery.

    PubMed

    Kim, Kang Rae; Lee, Young Min; Kim, Young Zoon; Cho, Yong Woon; Kim, Joon Soo; Kim, Kyu Hong; Lee, In Chang

    2013-09-01

    Atlanto-occipital assimilation is one of the most common osseous anomalies observed at the craniocervical junction. Most patients with atlas assimilation show no symptom, but some have neurological problems such as myelopathy that may require surgical treatment. Occipitocervical fusion may be required if atlato-occipital assimilation is accompanied by occipito-axial instability. However, in cases of symptomatic atlas assimilation with minor cord compression without instability, simple decompressive surgery may be the treatment modality. This report describes a case of successful treatment of a patient with myelopathy secondary to atlanto-occipital assimilation without instability, using posterior simple decompressive surgery. PMID:24757486

  6. Attenuating illusory binding with TMS of the right parietal cortex

    PubMed Central

    Esterman, Michael; Verstynen, Timothy; Robertson, Lynn C.

    2007-01-01

    A number of neuroimaging and neuropsychology studies have implicated various regions of parietal cortex as playing a critical role in the binding of color and form into conjunctions. The current study investigates the role of two such regions by examining how parietal transcranial magnetic stimulation (TMS) influences binding errors known as ‘illusory conjunctions.’ Participants made fewer binding errors after 1 Hz rTMS of the right intraparietal sulcus (IPS), while basic perception of features (colors and shape) was unaffected. No perceptual effects were found following left IPS stimulation, or stimulation of the right angular gyrus at the junction of the transverse occipital sulcus (IPS/TOS). These results support a role for the parietal cortex in feature binding but in ways that may require rethinking. PMID:17336097

  7. Frontal and occipital perfusion changes in dissociative identity disorder.

    PubMed

    Sar, Vedat; Unal, Seher N; Ozturk, Erdinc

    2007-12-15

    The aim of the study was to investigate if there were any characteristics of regional cerebral blood flow (rCBF) in dissociative identity disorder. Twenty-one drug-free patients with dissociative identity disorder and nine healthy volunteers participated in the study. In addition to a clinical evaluation, dissociative psychopathology was assessed using the Structured Clinical Interview for DSM-IV Dissociative Disorders, the Dissociative Experiences Scale and the Clinician-Administered Dissociative States Scale. A semi-structured interview for borderline personality disorder, the Hamilton Depression Rating Scale, and the Childhood Trauma Questionnaire were also administered to all patients. Normal controls had to be without a history of childhood trauma and without any depressive or dissociative disorder. Regional cerebral blood flow (rCBF) was studied with single photon emission computed tomography (SPECT) with Tc99m-hexamethylpropylenamine (HMPAO) as a tracer. Compared with findings in the control group, the rCBF ratio was decreased among patients with dissociative identity disorder in the orbitofrontal region bilaterally. It was increased in median and superior frontal regions and occipital regions bilaterally. There was no significant correlation between rCBF ratios of the regions of interest and any of the psychopathology scale scores. An explanation for the neurophysiology of dissociative psychopathology has to invoke a comprehensive model of interaction between anterior and posterior brain regions. PMID:17961993

  8. Occipital Condyle Fracture With Isolated Unilateral Hypoglossal Nerve Palsy

    PubMed Central

    Yoon, Jin Won; Lim, Oh Kyung; Park, Ki Deok

    2014-01-01

    Occipital condyle fractures (OCFs) with selective involvement of the hypoglossal canal are rare. OCFs usually occur after major trauma and combine multiple fractures. We describe a 38-year-old man who presented with neck pain and a tongue deviation to the right side after a traffic accident. Severe limitations were detected during active and passive range of neck motion in all directions. A physical examination revealed a normal gag reflex and normal mobility of the palate, larynx, and shoulder girdle. He had normal taste and general sensation in his tongue. However, he presented with a tongue deviation to the right side on protrusion. A videofluoroscopic swallowing study revealed piecemeal deglutition due to decreased tongue mobility but no aspiration of food. Plain X-ray film findings were negative, but a computed tomography study with coronal reconstruction demonstrated a right OCF involving the hypoglossal canal. An electrodiagnostic study revealed evidence of right hypoglossal nerve palsy. We report a rare case of isolated hypoglossal nerve palsy caused by an OCF. PMID:25379499

  9. Two-layer Lab-on-a-chip (LOC) with passive capillary valves for mHealth medical diagnostics.

    PubMed

    Balsam, Joshua; Bruck, Hugh Alan; Rasooly, Avraham

    2015-01-01

    There is a new potential to address needs for medical diagnostics in Point-of-Care (PoC) applications using mHealth (Mobile computing, medical sensors, and communications technologies for health care), a mHealth based lab test will require a LOC to perform clinical analysis. In this work, we describe the design of a simple Lab-on-a-chip (LOC) platform for mHealth medical diagnostics. The LOC utilizes a passive capillary valve with no moving parts for fluid control using channels with very low aspect ratios cross sections (i.e., channel width???height) achieved through transitions in the channel geometry via that arrest capillary flow. Using a CO2 laser in raster engraving mode, we have designed and fabricated an eight-channel LOC for fluorescence signal detection fabricated by engraving and combining just two polymer layers. Each of the LOC channels is capable of mixing two reagents (e.g., enzyme and substrate) for various assays. For mHealth detection, we used a mobile CCD detector equipped with LED multispectral illumination in the red, green, blue, and white range. This technology enables the development of low-cost LOC platforms for mHealth whose fabrication is compatible with standard industrial plastic fabrication processes to enable mass production of mHealth diagnostic devices, which may broaden the use of LOCs in PoC applications, especially in global health settings. PMID:25626544

  10. Traumatic Atlanto-Occipital Dislocation Presenting With Dysphagia as the Chief Complaint: A Case Report

    PubMed Central

    Choi, Eun Hye; Choi, Eun Hi; Shin, Ka Young; Cho, Ah Ra

    2013-01-01

    We report a patient with traumatic atlanto-occipital dislocation who presented with dysphagia as the chief complaint. A 59-year-old man complained of swallowing difficulty for 2 months after trauma to the neck. On physical examination, there was atrophy of the right sternocleidomastoid and upper trapezius muscles, and the tongue was deviated to the right. In a videofluoroscopic swallowing study, penetration and aspiration were not seen, food residue remained in the right vallecula and pyriform sinus, and there was decreased motion of the soft palate, pharynx and larynx. Electromyography confirmed a right spinal accessory nerve lesion. Magnetic resonance imaging confirmed atlanto-occipital dislocation. Dysphagia in atlanto-occipital dislocation is induced by medullary compression and lower cranial nerve injury. Therefore, in survivors who are diagnosed with atlanto-occipital dislocation, any neurological symptoms should be carefully evaluated. PMID:23869345

  11. Afferent projections of the rat major occipital nerve studied by transganglionic tansport of HRP

    Microsoft Academic Search

    S. Scheurer; J. Gottschall; V. Groh

    1983-01-01

    The central projection fields of cutaneous neurons of the rat's major occipital nerve have been investigated using the method of transganglionic transport of horseradish peroxidase (HRP), with tetramethyl-benzidine according to Mesulam (1978) as the chromogen.

  12. Effect of arginine vasopressin on the cortex edema in the ischemic stroke of Mongolian gerbils.

    PubMed

    Zhao, Xue-Yan; Wu, Chun-Fang; Yang, Jun; Gao, Yang; Sun, Fang-Jie; Wang, Da-Xin; Wang, Chang-Hong; Lin, Bao-Cheng

    2015-06-01

    Brain edema formation is one of the most important mechanisms of ischemia-evoked cerebral edema. It has been demonstrated that arginine vasopressin (AVP) receptors are involved in the pathophysiology of secondary brain damage after focal cerebral ischemia. In a well-characterized animal model of ischemic stroke of Mongolian gerbils, the present study was undertaken to clear the effect of AVP on cortex edema in cerebral ischemia. The results showed that (1) occluding the left carotid artery of Mongolian gerbils not only decreased the cortex specific gravity (cortex edema) but also increased AVP levels in the ipsilateral cortex (ischemic area) including left prefrontal lobe, left parietal lobe, left temporal lobe, left occipital lobe and left hippocampus for the first 6 hours, and did not change of the cortex specific gravity and AVP concentration in the right cortex (non-ischemic area); (2) there were many negative relationships between the specific gravity and AVP levels in the ischemic cortex; (3) intranasal AVP (50?ng or 200?ng), which could pass through the blood-brain barrier to the brain, aggravated the focal cortex edema, whereas intranasal AVP receptor antagonist-D(CH2)5Tyr(ET)DAVP (2?µg) mitigated the cortex edema in the ischemic area after occluding the left carotid artery of Mongolian gerbils; and (4) either intranasal AVP or AVP receptor antagonist did not evoke that edema in the non-ischemic cortex. The data indicated that AVP participated in the process of ischemia-evoked cortex edema, and the cerebral AVP receptor might serve as an important therapeutic target for the ischemia-evoked cortex edema. PMID:25843346

  13. Craniocervical stabilization of traumatic atlanto-occipital dislocation with minimal resultant neurological deficit

    Microsoft Academic Search

    P. S. Seibert; P. Stridh-Igo; T. A. Whitmore; B. M. Dufty; C. G. Zimmerman

    2005-01-01

    Summary Our purpose is to describe a case of atlanto-occipital dislocation and discuss treatment approaches to minimize subsequent neurological deficits. Traumatic atlanto-occipital dislocation, has traditionally been considered rare and lethal, due to resulting high levels of spinal cord injury. Outcomes are generally expected to be poor. However, recent case reports indicate that survival is increasing. Of patients who survive cranio-cervical

  14. Visuospatial Consciousness and Parieto-occipital Areas: A High-resolution EEG Study

    Microsoft Academic Search

    Claudio Babiloni; Fabrizio Vecchio; Maurizio Miriello; Gian Luca Romani; Paolo Maria Rossini

    2005-01-01

    Conscious and unconscious visuo-spatial processes are mainly related to parieto-occipital cortical activation. In this study, the working hypothesis was that a specific pattern of parieto-occipital activation is induced by conscious, as opposed to unconscious, visuo-spatial processes. Electroencephalographic data (128 chan- nels) were recorded in 12 normal adults during a visuo-spatial task. A cue stimulus appeared on the right or the

  15. Alternative psychosis and dysgraphia accompanied by forced normalization in a girl with occipital lobe epilepsy

    Microsoft Academic Search

    Yoshifumi Hirashima; Masafumi Morimoto; Akira Nishimura; Toshio Osamura; Tohru Sugimoto

    2008-01-01

    An 11-year-old girl who had been given antiepileptic drugs (AEDs) for occipital lobe epilepsy was hospitalized with alternative psychosis and dysgraphia accompanied by forced normalization of the EEG. Her epileptic seizures and psychosis disappeared after administration of carbamazepine. She developed dysgraphia for Kanji words (Japanese morphograms). The EEG showed sporadic spikes predominantly in the left occipital region, and [123I]iomazenil single-photon-emission

  16. A case of Dandy-Walker malformation associated with occipital meningocele, microphthalamia, and cleft palate

    Microsoft Academic Search

    S. Nishimaki; H. Yoda; K. Seki; T. Kawakami; H. Akamatsu; Y. Iwasaki

    1990-01-01

    We present a case of Dandy-Walker malformation associated with occipital meningocele, microphthalmia, and cleft palate. Small numbers of cases of Dandy-Walker malformation with occipital meningocele have been described in the literature, but to our knowledge, non of these also had microphthalmia or cleft palate. This association suggests that time of intrauterine origin of Dandy-Walker syndrome was in the sixth or

  17. Experience-Related Structural Changes of Degenerated Occipital White Matter in Late-Blind Humans – A Diffusion Tensor Imaging Study

    PubMed Central

    Dietrich, Susanne; Hertrich, Ingo; Kumar, Vinod; Ackermann, Hermann

    2015-01-01

    Late-blind humans can learn to understand speech at ultra-fast syllable rates (ca. 20 syllables/s), a capability associated with hemodynamic activation of the central-visual system. Thus, the observed functional cross-modal recruitment of occipital cortex might facilitate ultra-fast speech processing in these individuals. To further elucidate the structural prerequisites of this skill, diffusion tensor imaging (DTI) was conducted in late-blind subjects differing in their capability of understanding ultra-fast speech. Fractional anisotropy (FA) was determined as a quantitative measure of the directionality of water diffusion, indicating fiber tract characteristics that might be influenced by blindness as well as the acquired perceptual skills. Analysis of the diffusion images revealed reduced FA in late-blind individuals relative to sighted controls at the level of the optic radiations at either side and the right-hemisphere dorsal thalamus (pulvinar). Moreover, late-blind subjects showed significant positive correlations between FA and the capacity of ultra-fast speech comprehension within right-hemisphere optic radiation and thalamus. Thus, experience-related structural alterations occurred in late-blind individuals within visual pathways that, presumably, are linked to higher order frontal language areas. PMID:25830371

  18. Neovascular Age-Related Macular Degeneration Risk Based on CFH, LOC387715\\/HTRA1, and Smoking

    Microsoft Academic Search

    Anne E Hughes; Nick Orr; Chris Patterson; Hossein Esfandiary; Ruth Hogg; Vivienne McConnell; Giuliana Silvestri; Usha Chakravarthy

    2007-01-01

    BackgroundAge-related macular degeneration (AMD) is the major cause of blindness in the elderly. Those with the neovascular end-stage of disease have irreversible loss of central vision. AMD is a complex disorder in which genetic and environmental factors play a role. Polymorphisms in the complement factor H (CFH) gene, LOC387715, and the HTRA1 promoter are strongly associated with AMD. Smoking also

  19. Sounds activate visual cortex and improve visual discrimination.

    PubMed

    Feng, Wenfeng; Störmer, Viola S; Martinez, Antigona; McDonald, John J; Hillyard, Steven A

    2014-07-16

    A recent study in humans (McDonald et al., 2013) found that peripheral, task-irrelevant sounds activated contralateral visual cortex automatically as revealed by an auditory-evoked contralateral occipital positivity (ACOP) recorded from the scalp. The present study investigated the functional significance of this cross-modal activation of visual cortex, in particular whether the sound-evoked ACOP is predictive of improved perceptual processing of a subsequent visual target. A trial-by-trial analysis showed that the ACOP amplitude was markedly larger preceding correct than incorrect pattern discriminations of visual targets that were colocalized with the preceding sound. Dipole modeling of the scalp topography of the ACOP localized its neural generators to the ventrolateral extrastriate visual cortex. These results provide direct evidence that the cross-modal activation of contralateral visual cortex by a spatially nonpredictive but salient sound facilitates the discriminative processing of a subsequent visual target event at the location of the sound. Recordings of event-related potentials to the targets support the hypothesis that the ACOP is a neural consequence of the automatic orienting of visual attention to the location of the sound. PMID:25031419

  20. LocZ Is a New Cell Division Protein Involved in Proper Septum Placement in Streptococcus pneumoniae

    PubMed Central

    Hole?ková, Nela; Molle, Virginie; Buriánková, Karolína; Benada, Old?ich; Kofro?ová, Olga; Ulrych, Aleš; Branny, Pavel

    2014-01-01

    ABSTRACT How bacteria control proper septum placement at midcell, to guarantee the generation of identical daughter cells, is still largely unknown. Although different systems involved in the selection of the division site have been described in selected species, these do not appear to be widely conserved. Here, we report that LocZ (Spr0334), a newly identified cell division protein, is involved in proper septum placement in Streptococcus pneumoniae. We show that locZ is not essential but that its deletion results in cell division defects and shape deformation, causing cells to divide asymmetrically and generate unequally sized, occasionally anucleated, daughter cells. LocZ has a unique localization profile. It arrives early at midcell, before FtsZ and FtsA, and leaves the septum early, apparently moving along with the equatorial rings that mark the future division sites. Consistently, cells lacking LocZ also show misplacement of the Z-ring, suggesting that it could act as a positive regulator to determine septum placement. LocZ was identified as a substrate of the Ser/Thr protein kinase StkP, which regulates cell division in S. pneumoniae. Interestingly, homologues of LocZ are found only in streptococci, lactococci, and enterococci, indicating that this close phylogenetically related group of bacteria evolved a specific solution to spatially regulate cell division. PMID:25550321

  1. Preferential effect of isoflurane on top-down vs. bottom-up pathways in sensory cortex

    PubMed Central

    Raz, Aeyal; Grady, Sean M.; Krause, Bryan M.; Uhlrich, Daniel J.; Manning, Karen A.; Banks, Matthew I.

    2014-01-01

    The mechanism of loss of consciousness (LOC) under anesthesia is unknown. Because consciousness depends on activity in the cortico-thalamic network, anesthetic actions on this network are likely critical for LOC. Competing theories stress the importance of anesthetic actions on bottom-up “core” thalamo-cortical (TC) vs. top-down cortico-cortical (CC) and matrix TC connections. We tested these models using laminar recordings in rat auditory cortex in vivo and murine brain slices. We selectively activated bottom-up vs. top-down afferent pathways using sensory stimuli in vivo and electrical stimulation in brain slices, and compared effects of isoflurane on responses evoked via the two pathways. Auditory stimuli in vivo and core TC afferent stimulation in brain slices evoked short latency current sinks in middle layers, consistent with activation of core TC afferents. By contrast, visual stimuli in vivo and stimulation of CC and matrix TC afferents in brain slices evoked responses mainly in superficial and deep layers, consistent with projection patterns of top-down afferents that carry visual information to auditory cortex. Responses to auditory stimuli in vivo and core TC afferents in brain slices were significantly less affected by isoflurane compared to responses triggered by visual stimuli in vivo and CC/matrix TC afferents in slices. At a just-hypnotic dose in vivo, auditory responses were enhanced by isoflurane, whereas visual responses were dramatically reduced. At a comparable concentration in slices, isoflurane suppressed both core TC and CC/matrix TC responses, but the effect on the latter responses was far greater than on core TC responses, indicating that at least part of the differential effects observed in vivo were due to local actions of isoflurane in auditory cortex. These data support a model in which disruption of top-down connectivity contributes to anesthesia-induced LOC, and have implications for understanding the neural basis of consciousness. PMID:25339873

  2. LocARNAscan: Incorporating thermodynamic stability in sequence and structure-based RNA homology search

    PubMed Central

    2013-01-01

    Background The search for distant homologs has become an import issue in genome annotation. A particular difficulty is posed by divergent homologs that have lost recognizable sequence similarity. This same problem also arises in the recognition of novel members of large classes of RNAs such as snoRNAs or microRNAs that consist of families unrelated by common descent. Current homology search tools for structured RNAs are either based entirely on sequence similarity (such as blast or hmmer) or combine sequence and secondary structure. The most prominent example of the latter class of tools is Infernal. Alternatives are descriptor-based methods. In most practical applications published to-date, however, the information contained in covariance models or manually prescribed search patterns is dominated by sequence information. Here we ask two related questions: (1) Is secondary structure alone informative for homology search and the detection of novel members of RNA classes? (2) To what extent is the thermodynamic propensity of the target sequence to fold into the correct secondary structure helpful for this task? Results Sequence-structure alignment can be used as an alternative search strategy. In this scenario, the query consists of a base pairing probability matrix, which can be derived either from a single sequence or from a multiple alignment representing a set of known representatives. Sequence information can be optionally added to the query. The target sequence is pre-processed to obtain local base pairing probabilities. As a search engine we devised a semi-global scanning variant of LocARNA’s algorithm for sequence-structure alignment. The LocARNAscan tool is optimized for speed and low memory consumption. In benchmarking experiments on artificial data we observe that the inclusion of thermodynamic stability is helpful, albeit only in a regime of extremely low sequence information in the query. We observe, furthermore, that the sensitivity is bounded in particular by the limited accuracy of the predicted local structures of the target sequence. Conclusions Although we demonstrate that a purely structure-based homology search is feasible in principle, it is unlikely to outperform tools such as Infernal in most application scenarios, where a substantial amount of sequence information is typically available. The LocARNAscan approach will profit, however, from high throughput methods to determine RNA secondary structure. In transcriptome-wide applications, such methods will provide accurate structure annotations on the target side. Availability Source code of the free software LocARNAscan 1.0 and supplementary data are available at http://www.bioinf.uni-leipzig.de/Software/LocARNAscan. PMID:23601347

  3. Cortex morphology in first-episode psychosis patients with neurological soft signs.

    PubMed

    Gay, Olivier; Plaze, Marion; Oppenheim, Catherine; Mouchet-Mages, Sabine; Gaillard, Raphaël; Olié, Jean-Pierre; Krebs, Marie-Odile; Cachia, Arnaud

    2013-07-01

    Schizophrenia is a complex brain disorder associated with numerous etiological factors and pathophysiological pathways leading to multiple clinical outcomes. Compelling evidence suggests that deviations in neurodevelopmental processes are a major risk factor of schizophrenia. The identification of patients with high neurodevelopmental deviance is an important issue as it could help to identify homogeneous subgroups of patients with similar pathophysiological pathways, a key step to decipher the etiology of this complex condition. Several clinical arguments suggest that schizophrenia patients with Neurological Soft Signs (NSS)--ie, observable defects in motor coordination, motor integration, and sensory integration--would have high neurodevelopmental deviance. Based on the analysis of magnetic resonance imaging of 44 first-episode psychosis patients, we compared the cortex morphology, a marker of brain development, in patients with NSS vs patients with nonsignificant NSS. The cortex morphology was automatically assessed from three-dimensional global sulcal index (g-SI, the ratio between total sulcal area and outer cortex area) and regional sulcal indexes (r-SI, the ratio between the area of pooled labeled sulci and the total outer cortex area). Patients with NSS were found to have a lower g-SI in both hemispheres and a lower r-SI in left dorsolateral prefrontal and right lateral occipital cortices. Exploratory analyses revealed correlations between NSS dimensions and r-SI in distinct cortical areas, including dorsolateral and medial prefrontal cortices, lateral temporal, occipital, superior parietal, and medial parieto-occipital cortices. These findings provide evidence of distinct neurodevelopmental pathways in patients with NSS as compared with patients with nonsignificant NSS. PMID:22892556

  4. Transarticular screw fixation of C1-2 for the treatment of arthropathy-associated occipital neuralgia.

    PubMed

    Pakzaban, Peyman

    2011-02-01

    Two patients with occipital neuralgia due to severe arthropathy of the C1-2 facet joint were treated using atlantoaxial fusion with transarticular screws without decompression of the C-2 nerve root. Both patients experienced immediate postoperative relief of occipital neuralgia. The resultant motion elimination at C1-2 eradicated not only the movement-evoked pain, but also the paroxysms of true occipital neuralgia occurring at rest. A possible pathophysiological explanation for this improvement is presented in the context of the ignition theory of neuralgic pain. This represents the first report of C1-2 transarticular screw fixation for the treatment of arthropathy-associated occipital neuralgia. PMID:21214317

  5. Retinotopic maps and foveal suppression in the visual cortex of amblyopic adults.

    PubMed

    Conner, Ian P; Odom, J Vernon; Schwartz, Terry L; Mendola, Janine D

    2007-08-15

    Amblyopia is a developmental visual disorder associated with loss of monocular acuity and sensitivity as well as profound alterations in binocular integration. Abnormal connections in visual cortex are known to underlie this loss, but the extent to which these abnormalities are regionally or retinotopically specific has not been fully determined. This functional magnetic resonance imaging (fMRI) study compared the retinotopic maps in visual cortex produced by each individual eye in 19 adults (7 esotropic strabismics, 6 anisometropes and 6 controls). In our standard viewing condition, the non-tested eye viewed a dichoptic homogeneous mid-level grey stimulus, thereby permitting some degree of binocular interaction. Regions-of-interest analysis was performed for extrafoveal V1, extrafoveal V2 and the foveal representation at the occipital pole. In general, the blood oxygenation level-dependent (BOLD) signal was reduced for the amblyopic eye. At the occipital pole, population receptive fields were shifted to represent more parafoveal locations for the amblyopic eye, compared with the fellow eye, in some subjects. Interestingly, occluding the fellow eye caused an expanded foveal representation for the amblyopic eye in one early-onset strabismic subject with binocular suppression, indicating real-time cortical remapping. In addition, a few subjects actually showed increased activity in parietal and temporal cortex when viewing with the amblyopic eye. We conclude that, even in a heterogeneous population, abnormal early visual experience commonly leads to regionally specific cortical adaptations. PMID:17627994

  6. Retinotopic maps and foveal suppression in the visual cortex of amblyopic adults

    PubMed Central

    Conner, Ian P; Odom, J Vernon; Schwartz, Terry L; Mendola, Janine D

    2007-01-01

    Amblyopia is a developmental visual disorder associated with loss of monocular acuity and sensitivity as well as profound alterations in binocular integration. Abnormal connections in visual cortex are known to underlie this loss, but the extent to which these abnormalities are regionally or retinotopically specific has not been fully determined. This functional magnetic resonance imaging (fMRI) study compared the retinotopic maps in visual cortex produced by each individual eye in 19 adults (7 esotropic strabismics, 6 anisometropes and 6 controls). In our standard viewing condition, the non-tested eye viewed a dichoptic homogeneous mid-level grey stimulus, thereby permitting some degree of binocular interaction. Regions-of-interest analysis was performed for extrafoveal V1, extrafoveal V2 and the foveal representation at the occipital pole. In general, the blood oxygenation level-dependent (BOLD) signal was reduced for the amblyopic eye. At the occipital pole, population receptive fields were shifted to represent more parafoveal locations for the amblyopic eye, compared with the fellow eye, in some subjects. Interestingly, occluding the fellow eye caused an expanded foveal representation for the amblyopic eye in one early–onset strabismic subject with binocular suppression, indicating real-time cortical remapping. In addition, a few subjects actually showed increased activity in parietal and temporal cortex when viewing with the amblyopic eye. We conclude that, even in a heterogeneous population, abnormal early visual experience commonly leads to regionally specific cortical adaptations. PMID:17627994

  7. Synaptic proteins and choline acetyltransferase loss in visual cortex in dementia with Lewy bodies.

    PubMed

    Mukaetova-Ladinska, Elizabeta B; Andras, Alina; Milne, Joan; Abdel-All, Zeinab; Borr, Iwo; Jaros, Evelyn; Perry, Robert H; Honer, William G; Cleghorn, Andrea; Doherty, Jeanette; McIntosh, Gary; Perry, Elaine K; Kalaria, Raj N; McKeith, Ian G

    2013-01-01

    Functional neuroimaging studies have consistently reported abnormalities in the visual cortex in patients with dementia with Lewy bodies (DLB), but their neuropathologic substrates are poorly understood. We analyzed synaptic proteins and choline acetyltransferase (ChAT) in the primary (BA17) and association (BAs18/19) visual cortex in DLB and similar aged control and Alzheimer disease (AD) subjects. We found lower levels of synaptophysin, syntaxin, SNAP-25, and ?-synuclein in DLB subjects versus both aged control (68%-78% and 27%-72% for BA17 and BAs18/19, respectively) and AD cases (54%-67% and 10%-56% for BA17 and BAs18/19, respectively). The loss in ChAT activity in DLB cases was also greater in BA17 (72% and 87% vs AD and control values, respectively) than in BAs18/19 (52% and 65% vs AD and control groups, respectively). The observed synaptic and ChAT changes in the visual cortices were not associated with tau or ?-amyloid pathology in the occipital or the frontal, temporal, and parietal neocortex. However, the neocortical densities of LBs, particular those in BA17 and BAs18/19, correlated with lower synaptic and ChAT levels in these brain areas. These findings draw attention to molecular changes within the primary visual cortex in DLB and correlate with the neuroimaging findings within the occipital lobe in patients with this disorder. PMID:23242284

  8. Development of polymer lab-on-a-chip (LOC) for oxidation-reduction potential (ORP) measurement.

    PubMed

    Jang, A; Lee, K K; Bishop, P L; Kim, I S; Ahn, C H

    2011-01-01

    Reverse osmosis (RO) desalination has been recognized as a promising method to solve the water shortage problem. Nevertheless, since it is energy intensive and has many problems associated with biofouling/fouling of RO membranes in RO plants, its commercial acceptance is still slow. Especially, as high levels of oxidizing agents negatively affect RO membrane efficiency and life span. So, there is a need to develop sensitive, selective, portable and rapid methods to determine oxidation-reduction potential (ORP) in feed solution. For developing a polymer ORP lab-on-a-chip (LOC), a microchannel patterned on a polymer substrate was successfully filled with 800 nm diameter silica beads using self-assembly bead packing technology. The measured ORPs using the three kinds of redox potential solutions were typically slightly lower than those of the nominal redox potential. But, all of the measurements should be deemed acceptable. The ORP LOC has also a much shorter response time than the conventional potentiometric sensor. PMID:21977654

  9. Occipital Rhythmic Activity and Other Developmental Measures of Infants from High and Low Socioeconomic Groups.

    ERIC Educational Resources Information Center

    Inselberg, Rachel; And Others

    This study sought to determine whether differences existed between infants from low socioeconomic status (SES) families and those from high SES families in the occipital rhythmic activity of the brain, as recorded in their electroencephalograms (EEGs), as well as in other developmental measures. Ten low SES white infants and 10 high SES white…

  10. The white matter of the human cerebrum: Part I The occipital lobe by Heinrich Sachs

    PubMed Central

    Forkel, Stephanie J.; Mahmood, Sajedha; Vergani, Francesco; Catani, Marco

    2015-01-01

    This is the first complete translation of Heinrich Sachs' outstanding white matter atlas dedicated to the occipital lobe. This work is accompanied by a prologue by Prof Carl Wernicke who for many years was Sachs' mentor in Breslau and enthusiastically supported his work. PMID:25527430

  11. Atlanto-axial subluxation after pyogenic spondylitis of the atlanto-occipital joint.

    PubMed

    Tsunoda, Kazuhiko; Iizuka, Haku; Sorimachi, Yasunori; Ara, Tsuyoshi; Nishinome, Masahiro; Takechi, Yasuhiko; Takagishi, Kenji

    2011-07-01

    This report presents a case of atlanto-axial subluxation after treatment of pyogenic spondylitis of the atlanto-occipital joint. A 60-year-old male had 1-month history of neck pain with fever. Magnetic resonance imaging showed inflammation around the odontoid process. Intravenous antibiotic therapy was administrated immediately. After 6 weeks, CRP had returned almost to normal. After 4 months, laboratory data was still normal, but the patient experienced increasing neck pain. Lateral cervical radiography in the neutral position showed instability between C1 and C2. Computed tomography showed a bony union of the atlanto-occipital joint and severe destruction of the atlanto-axial joint on the left side. Transarticular screw fixation for the atlanto-axial joint was performed. A lateral cervical radiograph in the neutral position after surgery showed a solid bony union. Neck pain improved following surgery. We speculate that spondylitis of the atlanto-occipital joint induced a loosening of the transverse ligament and articulation of the atlanto-axial joint. A bony fusion of the atlanto-occipital joint after antibiotic treatment resolved the pyogenic inflammation concentrated stress to the damaged atlanto-axial joint, resulting in further damage. The atlanto-axial instability was finally managed by the insertion of a transarticular screw. PMID:21140176

  12. Occipital-device-related pain as a complication of deep brain stimulation.

    PubMed

    Yin, Shaoya; Jin, Weipeng; De Salles, Antonio

    2015-06-01

    Deep brain stimulation is an established treatment for movement disorders. We reported 4 patients (1.3%) of post-operative occipital headache related to the placement of the connection among 309 patients from 1998 to 2008. The patients were treated successfully by repositioning the connector into a groove created in the bone. PMID:25659960

  13. Repair of giant occipital encephaloceles with microcephaly secondary to massive brain herniation

    Microsoft Academic Search

    Anthony E. Gallo

    1992-01-01

    Giant occipital encephaloceles rarely contain large amounts of neural tissue that cannot be replaced in the abnormally small calvarium. Resection of neural elements is therefore often necessary in order to accomplish a closure. A technique is described wherein an extracranial compartment is prepared utilizing fine tantalum mesh to enclose the neural contents. The mesh is attached to the periphery of

  14. ???????Hair braids as a risk factor for occipital pressure ulcer development: a case study.

    PubMed

    Dixon, Marilu; Ratliff, Catherine

    2011-09-01

    The development of pressure ulcers in acute care settings remains an important concern, especially in high-risk populations such as patients who are critically ill and admitted to an ICU setting. In addition to immobility and other risk factors associated with critical illness, occipital pressure ulcer development has been associated with young age (neonates, infants, and young children) and patient care devices (cervical collars, bed lateral rotation). A 7-year-old boy was admitted to the pediatric intensive care unit with severe sepsis that progressed to multi-organ failure including respiratory distress requiring mechanical ventilation, cardiovascular failure requiring extracorporeal membrane oxygenation, and renal failure requiring dialysis. At 4 weeks, hair braids that were placed before admission were taken down, revealing five full-thickness occipital lesions. All wounds eventually healed, but scarring alopecia at the site of the largest wound was visible. This is the first case study describing hair braids as a potential risk factor for occipital pressure-related skin dam- age and suggests that if a patient is immobile and admitted with braids, patient/family and nursing staff education should include discussing the importance of releasing the hair to decrease the risk of occipital ulcers. PMID:21918247

  15. Stimulation of the greater occipital nerve induces increased central excitability of dural afferent input

    Microsoft Academic Search

    Thorsten Bartsch; Peter J. Goadsby

    2002-01-01

    Summary Patients with primary headaches often report pain that involves not only the front of the head, innervated by the first (ophthalmic) division of the trigeminal nerve, but also the back of the head, innervated by the greater occipital nerve (GON) that is a branch of the C2 spinal root. The aim of this work was to study the physiology

  16. Beyond Natural Numbers: Negative Number Representation in Parietal Cortex

    PubMed Central

    Blair, Kristen P.; Rosenberg-Lee, Miriam; Tsang, Jessica M.; Schwartz, Daniel L.; Menon, Vinod

    2012-01-01

    Unlike natural numbers, negative numbers do not have natural physical referents. How does the brain represent such abstract mathematical concepts? Two competing hypotheses regarding representational systems for negative numbers are a rule-based model, in which symbolic rules are applied to negative numbers to translate them into positive numbers when assessing magnitudes, and an expanded magnitude model, in which negative numbers have a distinct magnitude representation. Using an event-related functional magnetic resonance imaging design, we examined brain responses in 22 adults while they performed magnitude comparisons of negative and positive numbers that were quantitatively near (difference <4) or far apart (difference >6). Reaction times (RTs) for negative numbers were slower than positive numbers, and both showed a distance effect whereby near pairs took longer to compare. A network of parietal, frontal, and occipital regions were differentially engaged by negative numbers. Specifically, compared to positive numbers, negative number processing resulted in greater activation bilaterally in intraparietal sulcus (IPS), middle frontal gyrus, and inferior lateral occipital cortex. Representational similarity analysis revealed that neural responses in the IPS were more differentiated among positive numbers than among negative numbers, and greater differentiation among negative numbers was associated with faster RTs. Our findings indicate that despite negative numbers engaging the IPS more strongly, the underlying neural representation are less distinct than that of positive numbers. We discuss our findings in the context of the two theoretical models of negative number processing and demonstrate how multivariate approaches can provide novel insights into abstract number representation. PMID:22363276

  17. Implementing the Expert Object Recognition Pathway

    Microsoft Academic Search

    Bruce A. Draper; Kyungim Baek; Jeff Boody

    2003-01-01

    Brain imaging studies suggest that expert object recognition is a distinct visual skill, implemented by a dedi- cated anatomical pathway. Like all visual pathways, the ex- pert recognition pathway begins with the early visual system (retina, LGN\\/SC, striate cortex). It is defined, however, by subsequent diffuse activation in the lateral occipital complex (LOC) and sharp foci of activation in the

  18. PAPER www.rsc.org/loc | Lab on a Chip Fabrication of a modular tissue construct in a microfluidic chip

    E-print Network

    Prentiss, Mara

    PAPER www.rsc.org/loc | Lab on a Chip Fabrication of a modular tissue construct in a microfluidic cell behavior in vitro and in vivo,1,2 (ii) in generating realistic in vitro models of disease,3 culture, and may eventually have clinical uses,5,6 they are currently not ideal for high

  19. PAPER www.rsc.org/loc | Lab on a Chip Teflon films for chemically-inert microfluidic valves and pumps

    E-print Network

    Manalis, Scott

    800600h We present a simple method for fabricating chemically-inert Teflon microfluidic valves and pumps in glass microfluidic devices. These structures are modeled after monolithic membrane valves and pumpsPAPER www.rsc.org/loc | Lab on a Chip Teflon films for chemically-inert microfluidic valves

  20. Evaluation of spheno-occipital synchondrosis: A review of literature and considerations from forensic anthropologic point of view

    PubMed Central

    Krishan, Kewal; Kanchan, Tanuj

    2013-01-01

    Cranial sutures and synchondrosis have long been studied by forensic scientists, human anatomists, and anthropologists for estimation of age in different population groups. Observation of the closure of spheno-occipital synchondrosis has an important role to play in the estimation of age in the examination of unknown human remains when a skull is brought for examination. The present article reviews the studies conducted on the closure of spheno-occipital synchondrosis and presents a few valuable considerations that would be essential for carrying out research related to closure of spheno-occipital synchondrosis in humans. PMID:24255553

  1. Timely recognition of traumatic atlanto-occipital dislocation in a child based on occipital condyle-C1 interval analysis: excellent neurological recovery.

    PubMed

    Gluncic, Vicko; Turner, Michael; Kranzler, Leonard; Frim, David

    2010-05-01

    A case of atlanto-occipital dislocation (AOD) is presented to illustrate the importance of subtle imaging findings and the occipital condyle-C1 interval (CCI) measurement in the evaluation of high cervical spine injury. Although AOD is commonly considered to be fatal, recently there have been an increasing number of reports of children surviving this injury. Prompt recognition and treatment of AOD are crucial for survival. The authors present a case of an 8-year-old boy who sustained a destabilizing injury without bone disruption but with ligamentous tears that rendered his cervical spine unstable from the occiput to the C-1 level. On admission, imaging findings were consistent with tectorial membrane damage, perimedullary subarachnoid hemorrhage, and extraaxial blood from the clivus to the C-2 level. Most standard cervical spine radiological indices were within normal limits except the CCI. After initial management in a cervical collar, the patient was placed in halo vest, and subsequently underwent occiput to C-3 fusion. Timely recognition of the injury and subsequent craniocervical stabilization with internal fixation resulted in full neurological recovery. This report supports CCI as a valuable index for the prompt recognition of AOD. It also supports recent literature suggesting that AOD is a survivable injury with the possibility for an excellent neurological recovery. PMID:20433259

  2. Giant cell tumor of the occipital bone: A case report and review of the literature

    PubMed Central

    USLU, GONCA HANEDAN; CANYILMAZ, EMINE; YÖNEY, ADNAN; AYDIN, SEVDEGÜL; ?AHBAZ, ASLI; SARI, AHMET

    2014-01-01

    Giant cell tumors (GCTs) are usually found in the epiphysis of the long bones, and represent ~5% of all bone tumors. Only <1% of GCTs are localized in the cranium. When localized in the cranium, GCTs are commonly observed in the sphenoid or temporal bones, and rarely in the parietal or frontal bones. Occipital bone posterior fossa involvement is an extremely rare occurrence. The current study presents a 22-year-old female patient was admitted to the Department of Radiation Oncology (Karadeniz Technical University, Faculty of Medicine, Trabzon, Turkey) with complaints of neck pain and headache. The patients cranial magnetic resonance images showed a 2.5 6-cm mass in the occipital bone, which was subtotally excised. The patient was treated with radiotherapy following the surgery. At present, the patient has shown no progression after 20 months of follow-up. PMID:24959236

  3. Occipital Lobe Gray Matter Volume in Male Patients with Chronic Schizophrenia: A Quantitative MRI Study

    PubMed Central

    Onitsuka, Toshiaki; McCarley, Robert W.; Kuroki, Noriomi; Dickey, Chandlee C.; Kubicki, Marek; Demeo, Susan S.; Frumin, Melissa; Kikinis, Ron; Jolesz, Ferenc A.; Shenton, Martha E.

    2008-01-01

    Schizophrenia is characterized by deficits in cognition as well as visual perception. There have, however, been few magnetic resonance imaging (MRI) studies of the occipital lobe as an anatomically defined region of interest in schizophrenia. To examine whether or not patients with chronic schizophrenia show occipital lobe volume abnormalities, we measured gray matter volumes for both the primary visual area (PVA) and the visual association areas (VAA) using MRI based neuroanatomical landmarks and three-dimensional information. PVA and VAA gray matter volumes were measured using high-spatial resolution MRI in 25 male patients diagnosed with chronic schizophrenia and in 28 male normal controls. Chronic schizophrenia patients showed reduced bilateral VAA gray matter volume (11%), compared with normal controls, whereas patients showed no group difference in PVA gray matter volume. These results suggest that reduced bilateral VAA may be a neurobiological substrate of some of the deficits observed in early visual processing in schizophrenia. PMID:17350226

  4. Atlas occipitalization in a supersonic fighter pilot involved in a midair collision: a case report.

    PubMed

    Gips, Hadas; Hiss, Jehuda; Davidson, Benjamin

    2010-11-01

    We report a case of a midair collision between two F16 fighter aircraft, in which one pilot survived and the other was ejected upon impact and his remains recovered from sea. In autopsy, no patholgy was detected, other than the expected evidence of mechanical trauma. No defects in the aircraft or faults in the parachute or ejection mechanism were found. Reconstruction of the shattered skull base and the cervical vertebrae revealed fusion of the atlanto-occipital joint (occipitalization) and a left paracondylar process. The effective diameter of the spinal canal was decreased by the abnormal articulation. Such malformations can cause a wide range of neurologic deficits. Considering the skill and alertness needed to operate a supersonic fighter aircraft, with the pressure applied by the heavy protective head gear and various G forces endured by the spinal column during flight, we postulate that the collision was related to the pilot's sudden incapacitation. PMID:21121510

  5. Improvement in clinical outcomes after dry needling in a patient with occipital neuralgia

    PubMed Central

    Bond, Bryan M.; Kinslow, Christopher

    2015-01-01

    The primary purpose of this case report is to outline the diagnosis, intervention and clinical outcome of a patient presenting with occipital neuralgia. Upon initial presentation, the patient described a four-year history of stabbing neck pain and headaches. After providing informed consent, the patient underwent a total of four dry needling (DN) sessions over a two-week duration. During each of the treatment sessions, needles were inserted into the trapezii and suboccipital muscles. Post-intervention, the patient reported a 32-point change in her neck disability index score along with a 28-point change in her headache disability index score. Thus, it appears that subsequent four sessions of DN over two weeks, our patient experienced meaningful improvement in her neck pain and headaches. To the best of our knowledge, this is the first case report describing DN to successfully improve clinical outcomes in a patient diagnosed with occipital neuralgia.

  6. Homonymous Ganglion Cell Layer Thinning After Isolated Occipital Lesion: Macular OCT Demonstrates Transsynaptic Retrograde Retinal Degeneration.

    PubMed

    Meier, Paolo G; Maeder, Philippe; Kardon, Randy H; Borruat, François-Xavier

    2015-06-01

    A 48-year-old man was examined 24 months after medial and surgical treatment of an isolated well-circumscribed right occipital lobe abscess. An asymptomatic residual left homonymous inferior scotoma was present. Fundus examination revealed temporal pallor of both optic discs, and optical coherence tomography (OCT) revealed mild temporal loss of retinal nerve fiber layer in both eyes. No relative afferent pupillary defect was present. Assessment of the retinal ganglion cell layer demonstrated homonymous thinning in a pattern corresponding to the homonymous visual field loss. There were no abnormalities of the lateral geniculate nuclei or optic tracts on review of the initial brain computed tomography and follow-up magnetic resonance imaging. We believe our patient showed evidence of transsynaptic retrograde degeneration after an isolated right occipital lobe lesion, and the homonymous neuronal loss was detected on OCT by assessing the retinal ganglion cell layer. PMID:25285723

  7. Bilateral occipital calcification, epilepsy and coeliac disease: clinical and neuroimaging features of a new syndrome.

    PubMed Central

    Magaudda, A; Dalla Bernardina, B; De Marco, P; Sfaello, Z; Longo, M; Colamaria, V; Daniele, O; Tortorella, G; Tata, M A; Di Perri, R

    1993-01-01

    Twenty patients affected by bilateral occipital cortical-subcortical calcification (BOC) are described, 19 (95%) had epilepsy. In 8 of 16 cases studied, intestinal biopsy revealed coeliac disease. Fourteen patients had occipital partial epilepsy with a relatively benign outcome, while 4 patients were affected by a severe form of epilepsy, with very frequent, drug-resistant, generalised and partial seizures with mental deterioration. One patient had a single episode of convulsive status epilepticus at four months of age. The neurological examination was normal in all patients. CT showed flocculo-nodular, cortico-subcortical BOC, without enhancement and without lobar or hemispheric atrophy. MRI was normal. The clinical and neuroimaging features of these patients are different therefore from those with the Sturge-Weber Syndrome. The study confirms a high prevalence of coliac disease in patients with BOC, but the relationship between these two pathologies still needs to be clarified. Images PMID:8350105

  8. Bedside optical imaging of occipital resting-state functional connectivity in neonates

    PubMed Central

    White, Brian R.; Liao, Steve M.; Ferradal, Silvina L.; Inder, Terrie E.; Culver, Joseph P.

    2013-01-01

    Resting-state networks derived from temporal correlations of spontaneous hemodynamic fluctuations have been extensively used to elucidate the functional organization of the brain in adults and infants. We have previously developed functional connectivity diffuse optical tomography methods in adults, and we now apply these techniques to study functional connectivity in newborn infants at the bedside. We present functional connectivity maps in the occipital cortices obtained from healthy term-born infants and premature infants, including one infant with an occipital stroke. Our results suggest that functional connectivity diffuse optical tomography has potential as a valuable clinical tool for the early detection of functional deficits and for providing prognostic information on future development. PMID:21925609

  9. Neuropsychology of prefrontal cortex

    PubMed Central

    Siddiqui, Shazia Veqar; Chatterjee, Ushri; Kumar, Devvarta; Siddiqui, Aleem; Goyal, Nishant

    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 functional operations within the PFC. The specification of the component ‘executive’ processes and their localization to particular regions of PFC have been implicated in a wide variety of psychiatric disorders. PMID:19742233

  10. Different Cellular Types in Mesopontine Cholinergic Nuclei Related to Ponto-Geniculo-Occipital Waves

    Microsoft Academic Search

    M. Steriade; S. Datta; G. Oakson; R. Curt

    1990-01-01

    The only mesopontine neurons previously described as in- volved in the transfer of ponto-geniculo-occipital (PGO) waves from the brain stem to the thalamus were termed PGO-on bursting cells. We have studied, in chronically implanted cats, neuronal activities in brain-stem peribrachial (PB) and laterodorsal tegmental (LDT) cholinergic nuclei in relation to PGO waves recorded from the lateral geniculate (LG) tha- lamic

  11. Metabolic and Molecular Bases of Menkes Disease and Occipital Horn Syndrome

    Microsoft Academic Search

    1998-01-01

    Menkes disease and occipital horn syndrome (OHS) are related disorders of copper transport that involve abnormal neurodevelopment,\\u000a connective tissue problems, and often premature death. Location of the gene responsible for these conditions on the X chromosome\\u000a was indicated by pedigree analysis from the time of these syndromes' earliest descriptions. Characterization of an affected\\u000a female with an X-autosomal translocation was used

  12. Giant Pediatric Aneurysmal Bone Cysts of the Occipital Bone: Case Report and Review of the Literature

    Microsoft Academic Search

    Jacob Genizi; Srugo Isaac; Attias Dina; Ben-Sira Liat; Braun Jacob; Bamberger S. Ellen; Margalit Nevo; Constantini Shlomi

    2011-01-01

    Cranial aneurysmal bone cysts are uncommon. Cranial aneurysmal bone cysts of the occipital bone are exceedingly rare. A 2-year-old toddler with this rare cyst presented with a large space-occupying lesion of the posterior fossa, with cerebellar tonsillar herniation. The patient experienced complete recovery after total excision of the lesion. We review the literature regarding this rare presentation, and discuss the

  13. Atlantoaxial subluxation after pyogenic spondylitis of the atlanto-occipital joint

    Microsoft Academic Search

    Kazuhiko Tsunoda; Haku Iizuka; Yasunori Sorimachi; Tsuyoshi Ara; Masahiro Nishinome; Yasuhiko Takechi; Kenji Takagishi

    2011-01-01

    This report presents a case of atlanto-axial subluxation after treatment of pyogenic spondylitis of the atlanto-occipital\\u000a joint. A 60-year-old male had 1-month history of neck pain with fever. Magnetic resonance imaging showed inflammation around\\u000a the odontoid process. Intravenous antibiotic therapy was administrated immediately. After 6 weeks, CRP had returned almost\\u000a to normal. After 4 months, laboratory data was still normal, but the

  14. Category Learning Increases Discriminability of Relevant Object Dimensions in Visual Cortex

    PubMed Central

    Palmeri, Thomas J.; Gauthier, Isabel

    2013-01-01

    Learning to categorize objects can transform how they are perceived, causing relevant perceptual dimensions predictive of object category to become enhanced. For example, an expert mycologist might become attuned to species-specific patterns of spacing between mushroom gills but learn to ignore cap textures attributable to varying environmental conditions. These selective changes in perception can persist beyond the act of categorizing objects and influence our ability to discriminate between them. Using functional magnetic resonance imaging adaptation, we demonstrate that such category-specific perceptual enhancements are associated with changes in the neural discriminability of object representations in visual cortex. Regions within the anterior fusiform gyrus became more sensitive to small variations in shape that were relevant during prior category learning. In addition, extrastriate occipital areas showed heightened sensitivity to small variations in shape that spanned the category boundary. Visual representations in cortex, just like our perception, are sensitive to an object's history of categorization. PMID:22490547

  15. Neurological and neuropsychological characteristics of occipital, occipito-temporal and occipito-parietal infarction.

    PubMed

    Kraft, Antje; Grimsen, Cathleen; Kehrer, Stefanie; Bahnemann, Markus; Spang, Karoline; Prass, Maren; Irlbacher, Kerstin; Köhnlein, Martin; Lipfert, Anika; Brunner, Freimuth; Kastrup, Andreas; Fahle, Manfred; Brandt, Stephan A

    2014-07-01

    Neuropsychological deficits after occipital infarction are most often described in case studies and only a small sample of studies has attempted to exactly correlate the anatomical localization of lesions with associated neuropsychological symptoms. The present study investigated a large number of patients (N = 128) in order to provide an overview of neurological and neuropsychological deficits after occipital, occipito-temporal and occipito-parietal infarction. A particular approach of the study was to define exact anatomical correlates of neuropsychological dysfunction by using voxel-based lesion-symptom mapping (VLSM) in 61 patients. In addition to a visual field defect and phosphenes, patients often reported anomia, difficulties in reading and memory deficits. Visual disorders, such as achromatopsia, akinetopsia or prosopagnosia, were rarely reported by the patients. Memory and visual disorders were diagnosed efficiently using simple clinical screening tests, such as the Rey-Osterrieth Complex Figure Test for immediate recall, the Demtect and the Lang Stereo Test. Visual field defects, reading disorders and the perception of phosphenes were associated primarily with lesions of the calcarine sulcus. Anomia and memory deficits were related to lesions of the occipital inferior gyrus, the lingual gyrus and hippocampus, as well as to lesions of principal white matter tracts. PMID:23206528

  16. [Transient charles bonnet syndrome after excision of a right occipital meningioma: a case report].

    PubMed

    Arai, Takao; Hasegawa, Yuzuru; Tanaka, Toshihide; Kato, Naoki; Watanabe, Mitsuyoshi; Nakamura, Aya; Murayama, Yuichi

    2014-05-01

    Charles Bonnet syndrome is a condition characterized by visual hallucinations. These simple or complex visual hallucinations are more common in elderly individuals with impaired peripheral vision. The current report describes a case of transient Charles Bonnet syndrome appearing after the removal of a meningioma. The patient was a 61-year-old man who already had impaired visual acuity due to diabetic retinopathy. Brain MRI revealed a cystic tumor severely compressing the right occipital lobe. Starting on day 2 postoperatively, the patient was troubled by recurring visual hallucinations involving people, flowers, pictures, and familiar settings(the train and a coffee shop). These continued for 3.5 months. This period roughly coincided with the time for the occipital lobe to recover from the compression caused by the tumor, a fact that was confirmed by several MRI scans. ¹²³I-IMP SPECT performed 1 month after the surgical operation showed an area of hypoperfusion in the right parieto-occipital lobe. Based on the patient's clinical course and MRI findings, the mechanism of onset of visual hallucinations in this patient was put forward. The release of pressure in the brain by tumor removal and subsequent recovery changed the blood flow to the brain. This triggered visual hallucinations in the patient, who was already predisposed to developing Charles Bonnet syndrome because of diabetic retinopathy. This case is interesting since it indicates that central neurological factors, as well as visual deficits, may induce the appearance of visual hallucinations in Charles Bonnet syndrome. PMID:24807549

  17. The Orbitofrontal Cortex and Reward

    Microsoft Academic Search

    Edmund T. Rolls

    2000-01-01

    The primate 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 odors is represented. The orbitofrontal cortex also receives information about the sight of objects and faces from the temporal

  18. Coarse-to-fine categorization of visual scenes in scene-selective cortex.

    PubMed

    Musel, Benoit; Kauffmann, Louise; Ramanoël, Stephen; Giavarini, Coralie; Guyader, Nathalie; Chauvin, Alan; Peyrin, Carole

    2014-10-01

    Neurophysiological, behavioral, and computational data indicate that visual analysis may start with the parallel extraction of different elementary attributes at different spatial frequencies and follows a predominantly coarse-to-fine (CtF) processing sequence (low spatial frequencies [LSF] are extracted first, followed by high spatial frequencies [HSF]). Evidence for CtF processing within scene-selective cortical regions is, however, still lacking. In the present fMRI study, we tested whether such processing occurs in three scene-selective cortical regions: the parahippocampal place area (PPA), the retrosplenial cortex, and the occipital place area. Fourteen participants were subjected to functional scans during which they performed a categorization task of indoor versus outdoor scenes using dynamic scene stimuli. Dynamic scenes were composed of six filtered images of the same scene, from LSF to HSF or from HSF to LSF, allowing us to mimic a CtF or the reverse fine-to-coarse (FtC) sequence. Results showed that only the PPA was more activated for CtF than FtC sequences. Equivalent activations were observed for both sequences in the retrosplenial cortex and occipital place area. This study suggests for the first time that CtF sequence processing constitutes the predominant strategy for scene categorization in the PPA. PMID:24738768

  19. The Effect of Cataract Severity and Morphology on the Reliability of the Lens Opacities Classification System II (LOCS II)

    Microsoft Academic Search

    Giovanni Maraini; Paolo Pasquini; Robert D. Sperduto; Mirca Donacini; MariaParrizia Carrieri; Rosamaria Corona; Paolo Graziosi; MariaCarla Tomba; Sally L. Williams

    Data collected from 3646 eyes in the Italian-American Natural History Study of Age-Related Cataract were used to investigate whether the reliability of the Lens Opacities Classification System II (LOCS II) by the severity of the opacity that is being graded or is influenced by the presence and severity of coexisting opacities. Reliability was assessed by comparing the slit-lamp gradings of

  20. The auditory cortex

    Microsoft Academic Search

    G. Ehret

    1997-01-01

    The division of the auditory cortex into various fields, functional aspects of these fields, and neuronal coding in the primary\\u000a auditory cortical field (AI) are reviewed with stress on features that may be common to mammals. On the basis of 14 topographies\\u000a and clustered distributions of neuronal response characteristics in the primary auditory cortical field, a hypothesis is developed\\u000a of

  1. Where are inion and endinion? Variations of the exo- and endocranial morphology of the occipital bone during hominin evolution.

    PubMed

    Balzeau, Antoine; Grimaud-Hervé, Dominique; Gilissen, Emmanuel

    2011-10-01

    The occipital bone is frequently investigated in paleoanthropological studies because it has several features that help to differentiate various fossil hominin species. Among these features is the separation between inion and endinion, which has been proposed to be an autapomorphic trait in (Asian) Homo erectus. Methodologies are developed here to quantify for the first time the location of these anatomical points, and to interpret their variation due to the complex interactions between exocranial and endocranial size and shape of the occipital and nuchal planes, as well as the occipital lobes and cerebellum. On the basis of our analysis, neither 'the separation between inion and endinion' nor 'endinion below inion' can be considered as an autapomorphic trait in H. erectus, since this feature is a condition shared by extant African great apes and fossil hominins. Moreover, our results show that the exo- and endocranial anatomy of the occipital bone differs between hominins (except Paranthropus boisei specimens and KNM-ER 1805) and great apes. For example, chimpanzees and bonobos are characterized by a very high position of inion and their occipital bone shows an antero-posterior compression. However, these features are partly correlated with their small size when compared with hominins. Asian H. erectus specimens have a thick occipital torus, but do not differ from other robust specimens, neither in this feature nor in the analysed exo- and endocranial proportions of the occipital bone. Finally, the apparent brain size reduction during the Late Pleistocene and variation between the sexes in anatomically modern humans (AMH) reflect that specimens with smaller brains have a relatively larger posterior height of the cerebellum. However, this trend is not the sole explanation for the 'vertical shift' of endinion above inion that appears occasionally and exclusively in AMH. PMID:21855115

  2. Mechanisms of migraine aura revealed by functional MRI in human visual cortex.

    PubMed

    Hadjikhani, N; Sanchez Del Rio, M; Wu, O; Schwartz, D; Bakker, D; Fischl, B; Kwong, K K; Cutrer, F M; Rosen, B R; Tootell, R B; Sorensen, A G; Moskowitz, M A

    2001-04-10

    Cortical spreading depression (CSD) has been suggested to underlie migraine visual aura. However, it has been challenging to test this hypothesis in human cerebral cortex. Using high-field functional MRI with near-continuous recording during visual aura in three subjects, we observed blood oxygenation level-dependent (BOLD) signal changes that demonstrated at least eight characteristics of CSD, time-locked to percept/onset of the aura. Initially, a focal increase in BOLD signal (possibly reflecting vasodilation), developed within extrastriate cortex (area V3A). This BOLD change progressed contiguously and slowly (3.5 +/- 1.1 mm/min) over occipital cortex, congruent with the retinotopy of the visual percept. Following the same retinotopic progression, the BOLD signal then diminished (possibly reflecting vasoconstriction after the initial vasodilation), as did the BOLD response to visual activation. During periods with no visual stimulation, but while the subject was experiencing scintillations, BOLD signal followed the retinotopic progression of the visual percept. These data strongly suggest that an electrophysiological event such as CSD generates the aura in human visual cortex. PMID:11287655

  3. The cerebral cortex of the pygmy hippopotamus, Hexaprotodon liberiensis (Cetartiodactyla, Hippopotamidae): MRI, cytoarchitecture, and neuronal morphology.

    PubMed

    Butti, Camilla; Ewan Fordyce, R; Ann Raghanti, Mary; Gu, Xiaosi; Bonar, Christopher J; Wicinski, Bridget A; Wong, Edmund W; Roman, Jessica; Brake, Alanna; Eaves, Emily; Spocter, Muhammad A; Tang, Cheuk Y; Jacobs, Bob; Sherwood, Chet C; Hof, Patrick R

    2014-04-01

    The structure of the hippopotamus brain is virtually unknown because few studies have examined more than its external morphology. In view of their semiaquatic lifestyle and phylogenetic relatedness to cetaceans, the brain of hippopotamuses represents a unique opportunity for better understanding the selective pressures that have shaped the organization of the brain during the evolutionary process of adaptation to an aquatic environment. Here we examined the histology of the cerebral cortex of the pygmy hippopotamus (Hexaprotodon liberiensis) by means of Nissl, Golgi, and calretinin (CR) immunostaining, and provide a magnetic resonance imaging (MRI) structural and volumetric dataset of the anatomy of its brain. We calculated the corpus callosum area/brain mass ratio (CCA/BM), the gyrencephalic index (GI), the cerebellar quotient (CQ), and the cerebellar index (CI). Results indicate that the cortex of H. liberiensis shares one feature exclusively with cetaceans (the lack of layer IV across the entire cerebral cortex), other features exclusively with artiodactyls (e.g., the morphologiy of CR-immunoreactive multipolar neurons in deep cortical layers, gyrencephalic index values, hippocampus and cerebellum volumetrics), and others with at least some species of cetartiodactyls (e.g., the presence of a thick layer I, the pattern of distribution of CR-immunoreactive neurons, the presence of von Economo neurons, clustering of layer II in the occipital cortex). The present study thus provides a comprehensive dataset of the neuroanatomy of H. liberiensis that sets the ground for future comparative studies including the larger Hippopotamus amphibius. PMID:24474726

  4. Visual cortex in aging and Alzheimer's disease: changes in visual field maps and population receptive fields

    PubMed Central

    Brewer, Alyssa A.; Barton, Brian

    2012-01-01

    Although several studies have suggested that cortical alterations underlie such age-related visual deficits as decreased acuity, little is known about what changes actually occur in visual cortex during healthy aging. Two recent studies showed changes in primary visual cortex (V1) during normal aging; however, no studies have characterized the effects of aging on visual cortex beyond V1, important measurements both for understanding the aging process and for comparison to changes in age-related diseases. Similarly, there is almost no information about changes in visual cortex in Alzheimer's disease (AD), the most common form of dementia. Because visual deficits are often reported as one of the first symptoms of AD, measurements of such changes in the visual cortex of AD patients might improve our understanding of how the visual system is affected by neurodegeneration as well as aid early detection, accurate diagnosis and timely treatment of AD. Here we use fMRI to first compare the visual field map (VFM) organization and population receptive fields (pRFs) between young adults and healthy aging subjects for occipital VFMs V1, V2, V3, and hV4. Healthy aging subjects do not show major VFM organizational deficits, but do have reduced surface area and increased pRF sizes in the foveal representations of V1, V2, and hV4 relative to healthy young control subjects. These measurements are consistent with behavioral deficits seen in healthy aging. We then demonstrate the feasibility and first characterization of these measurements in two patients with mild AD, which reveal potential changes in visual cortex as part of the pathophysiology of AD. Our data aid in our understanding of the changes in the visual processing pathways in normal aging and provide the foundation for future research into earlier and more definitive detection of AD. PMID:24570669

  5. Occipital condyle screw placement and occipitocervical instrumentation using three-dimensional image-guided navigation.

    PubMed

    Le, Tien V; Burkett, Clint; Ramos, Edwin; Uribe, Juan S

    2012-05-01

    Occipital condyle (OC) screws are an alternative cephalad fixation point in occipitocervical fusion. Safe placement of occipital, C1 lateral mass, and C2 pars screws have been described previously, but not OC screws. The craniocervical junction is complex, and a thorough understanding of the anatomy is needed. Three-dimensional (3D) image-guided navigation was used in six patients. There were no complications related to image-guided navigation during the placement of 12 OC screws and we found that this navigation can serve as a useful adjunct when placing an OC screw. Technical considerations of placing OC and C1 lateral mass screws are discussed with particular reference to patient positioning and the StealthStation® S7™ image-guided navigational platform (Medtronic, Minneapolis, MN, USA). The reference arc is attached to the head-clamp and faces forward. The optical camera and monitor are positioned at the head of the table for a direct, non-obstructed line-of-sight. To minimize intersegmental movement, the OC should not be drilled until all other screws have been placed. We conclude that 3D image-guided navigation is a useful adjunct that can be safely and effectively used for placement of instrumentation of the upper cervical spine including the OC. PMID:22356730

  6. Radiation-induced malignant fibrous histiocytoma of the occipital: a case report

    PubMed Central

    2014-01-01

    Malignant fibrous histiocytoma (MFH) is a rare neoplasm exhibiting a propensity for aggressive clinical behavior. Effective treatment modality is surgical resection with wide margins, but its rate of recurrence and metastasis is still high. Early detection and complete excision of the tumor is necessary. A MFH of the occipital developed in a 51-year-old woman eight years after surgery and radiation for medulloblastoma of the cerebellar vermis. The secondary neoplasm arose at the site of tumor resection within the irradiated field, and was resected. The development of sarcomas is a recognized complication of radiation therapy. The final diagnosis after the operation was MFH. Radiation-induced sarcoma (RIS) is well known, but radiation-induced MFH is relatively rare in the head and neck region, especially in the occipital. The imaging findings are not diagnosis specific, but strict follow-up within the radiation field by computerized tomography (CT) and magnetic resonance imaging (MRI) and appreciation of the expected latency period may help in providing the diagnosis of RIS. PMID:24742094

  7. Electrochemical dissolved oxygen removal from microfluidic streams for LOC sample pretreatment.

    PubMed

    Marei, Mohamed M; Roussel, Thomas J; Keynton, Robert S; Baldwin, Richard P

    2014-09-01

    Current water quality monitoring for heavy metal contaminants largely results in analytical snapshots at a particular time and place. Therefore, we have been interested in miniaturized and inexpensive sensors suitable for long-term, real-time monitoring of the drinking water distribution grid, industrial wastewater effluents, and even rivers and lakes. Among the biggest challenges for such sensors are the issues of in-field device calibration and sample pretreatment. Previously, we have demonstrated use of coulometric stripping analysis for calibration-free determination of copper and mercury. For more negatively reduced metals, O2 reduction interferes with stripping analysis; hence, most electroanalysis techniques rely on pretreatments to remove dissolved oxygen (DO). Current strategies for portable DO removal offer limited practicality, because of their complexity, and often cause inadvertent sample alterations. Therefore, we have designed an indirect in-line electrochemical DO removal device (EDOR), utilizing a silver cathode to reduce DO in a chamber that is fluidically isolated from the sample stream by an O2-permeable membrane. The resulting concentration gradient supports passive DO diffusion from the sample stream into the deoxygenation chamber. The DO levels in the sample stream were determined by cyclic voltammetry (CV) and amperometry at a custom thin-layer cell (TLC) detector. Results show removal of 98% of the DO in a test sample at flow rates approaching 50 ?L/min and power consumption as low as 165 mW h L(-1) at steady state. Besides our specific stripping application, this device is well-suited for LOC applications where miniaturized DO removal and/or regulation are desirable. PMID:25082792

  8. Placement of occipital condyle screws for occipitocervical fixation in a pediatric patient with occipitocervical instability after decompression for Chiari malformation.

    PubMed

    Bekelis, Kimon; Duhaime, Ann-Christine; Missios, Symeon; Belden, Clifford; Simmons, Nathan

    2010-08-01

    In cadaveric studies and recently in one adult patient the occipital condyle has been studied as an option to allow bone purchase by fixation devices. In the current case the authors describe the use of occipital condyle screws in a child undergoing occipitocervical fixation. To the best of the authors' knowledge this case is the first reported instance of this technique in a pediatric patient. This girl had a history of posterior fossa decompression for Chiari malformation Type I when she was 22 months of age. When she was 6 years old she presented with neck pain on flexion and extension of her head. Magnetic resonance imaging in flexion and extension revealed occipitocervical instability. She underwent an occiput to C-2 posterior arthrodesis with bilateral screw placement in the occipital condyles, C-2 lamina, and C-1 lateral masses. Postoperatively, she was neurologically intact. Computed tomography demonstrated a stable construct, and her cervical pain had resolved on follow-up. PMID:20672939

  9. Pulsed radiofrequency to the great occipital nerve for the treatment of intractable postherpetic itch: a case report

    PubMed Central

    Ding, De-Fang; Li, Rong-Chun; Xiong, Qiu-Ju; Zhou, Ling; Xiang, Hong-Bing

    2014-01-01

    A patient with intractable postherpetic itch lasting for 1 year was reported. The itch was mainly from the left vertex, frontal and ophthalmic regions and extended to the left neck area. The patient had negative response to the ophthalmic nerve block. Under the initial positive response to the great occipital nerve block, pulsed radiofrequency (PRF) was performed on the position of the great occipital nerve. After 4 months treatment, the itch was completely vanished. This case study demonstrates the effectiveness of PRF for intractable postherpetic itch originating in the head and neck. However, more samples needed to verify this management. PMID:25419389

  10. The Distributed Auditory Cortex

    PubMed Central

    Winer, Jeffery A.; Lee, Charles C.

    2009-01-01

    A synthesis of cat auditory cortex (AC) organization is presented in which the extrinsic and intrinsic connections interact to derive a unified profile of the auditory stream and use it to direct and modify cortical and subcortical information flow. Thus, the thalamocortical input provides essential sensory information about peripheral stimulus events, which AC redirects locally for feature extraction, and then conveys to parallel auditory, multisensory, premotor, limbic, and cognitive centers for further analysis. The corticofugal output influences areas as remote as the pons and the cochlear nucleus, structures whose effects upon AC are entirely indirect, and has diverse roles in the transmission of information through the medial geniculate body and inferior colliculus. The distributed AC is thus construed as a functional network in which the auditory percept is assembled for subsequent redistribution in sensory, premotor, and cognitive streams contingent on the derived interpretation of the acoustic events. The confluence of auditory and multisensory streams likely precedes cognitive processing of sound. The distributed AC constitutes the largest and arguably the most complete representation of the auditory world. Many facets of this scheme may apply in rodent and primate AC as well. We propose that the distributed auditory cortex contributes to local processing regimes in regions as disparate as the frontal pole and the cochlear nucleus to construct the acoustic percept. PMID:17329049

  11. Word Recognition in Auditory Cortex

    ERIC Educational Resources Information Center

    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. mPLR-Loc: an adaptive decision multi-label classifier based on penalized logistic regression for protein subcellular localization prediction.

    PubMed

    Wan, Shibiao; Mak, Man-Wai; Kung, Sun-Yuan

    2015-03-15

    Proteins located in appropriate cellular compartments are of paramount importance to exert their biological functions. Prediction of protein subcellular localization by computational methods is required in the post-genomic era. Recent studies have been focusing on predicting not only single-location proteins but also multi-location proteins. However, most of the existing predictors are far from effective for tackling the challenges of multi-label proteins. This article proposes an efficient multi-label predictor, namely mPLR-Loc, based on penalized logistic regression and adaptive decisions for predicting both single- and multi-location proteins. Specifically, for each query protein, mPLR-Loc exploits the information from the Gene Ontology (GO) database by using its accession number (AC) or the ACs of its homologs obtained via BLAST. The frequencies of GO occurrences are used to construct feature vectors, which are then classified by an adaptive decision-based multi-label penalized logistic regression classifier. Experimental results based on two recent stringent benchmark datasets (virus and plant) show that mPLR-Loc remarkably outperforms existing state-of-the-art multi-label predictors. In addition to being able to rapidly and accurately predict subcellular localization of single- and multi-label proteins, mPLR-Loc can also provide probabilistic confidence scores for the prediction decisions. For readers' convenience, the mPLR-Loc server is available online (http://bioinfo.eie.polyu.edu.hk/mPLRLocServer). PMID:25449328

  13. Retrosplenial cortex connectivity in schizophrenia.

    PubMed

    Bluhm, Robyn L; Miller, Jodi; Lanius, Ruth A; Osuch, Elizabeth A; Boksman, Kristine; Neufeld, Richard W J; Théberge, Jean; Schaefer, Betsy; Williamson, Peter C

    2009-10-30

    In this paper, we build on our previous analysis [Bluhm, R.L., Miller, J., Lanius, R.A., Osuch, E.A., Boksman, K., Neufeld, R.W.J., et al., 2007 Spontaneous low-frequency fluctuations in the BOLD signal in schizophrenic patients: anomalies in the default network. Schizophrenia Bulletin 33, 1004-1012] of resting state connectivity in schizophrenia by examining alterations in connectivity of the retrosplenial cortex. We have previously demonstrated altered connectivity of the posterior cingulate/precuneus, particularly with other regions of the "default network" (which includes the medial prefrontal cortex and bilateral lateral parietal cortex). It was hypothesized that the retrosplenial cortex would show aberrant patterns of connectivity with regions of the default network and regions associated with memory. Patients with schizophrenia (N=17) and healthy controls (N=17) underwent a 5.5-min resting functional magnetic resonance imaging scan. Lower correlations were observed in patients with schizophrenia than in healthy controls between the retrosplenial cortex and both the temporal lobe and regions of the default network. In patients with schizophrenia, activity in the retrosplenial cortex correlated negatively with activity in bilateral anterior cingulate gyrus/medial prefrontal cortex (BA 32/10), despite the fact that these regions, as part of the default network, were expected to show positive correlations in activity. Connectivity of the retrosplenial cortex was greater in patients with more positive symptoms with areas previously associated with hallucinations, particularly the left superior temporal gyrus. These results suggest that spontaneous activity in the retrosplenial cortex during rest is altered in patients with schizophrenia. These alterations may help to explain alterations in self-oriented processing in this patient population. PMID:19783410

  14. Paediatric epilepsy surgery in the posterior cortex: a study of 62 cases.

    PubMed

    Liava, Alexandra; Mai, Roberto; Tassi, Laura; Cossu, Massimo; Sartori, Ivana; Nobili, Lino; Lo Russo, Giorgio; Francione, Stefano

    2014-06-01

    Past surgical series have emphasized the diagnostic complexity of posterior cortex epilepsy. Available data are sparse, especially in children, and most published series report a high number of surgical failures and post-operative neurological deficits. In this article, we present a paediatric cohort of 62 children who underwent surgery for drug resistant posterior cortex epilepsy before the age of 16 years with a mean post-operative follow-up of 6.94 years (range: 2-16). Mean age at epilepsy onset was 3.2 years and 28 children (45%) had onset before 1 year of age. The mean age at surgery was 7.9 years (range: 1-16). Daily seizures were present in 63% of children. MRI was positive in 58 cases (93.5%) and invasive stereo-EEG was judged mandatory in 24/62 (39%) of patients. Surgery was confined to the parietal lobe in 11 children, the occipital lobe in 8, the occipito-parietal region in four, the occipito-temporal region in 18, and involved both the temporal and parietal lobes in the remaining 21. Following surgery, 53 subjects (85.5%) remained seizure-free and among those who underwent a SEEG procedure, 75% achieved seizure freedom. Focal cortical dysplasia was the most frequent histopathological diagnosis (50%), followed by tumoural (24%) and gliotic lesions (14.5%). An older age at epilepsy onset, the presence of a rather restricted epileptogenic area, and a complete resection of the epileptogenic zone were predictive of a favourable surgical outcome. These results demonstrate that a good surgical outcome is possible in children with drug resistant posterior cortex epilepsy. Accurate analysis of the chronology of ictal semiology and electrophysiological features, viewed in the context of the complete electroclinical pattern, provides a topographical orientation for posterior cortex epilepsy and, together with the presence of a lesion detectable on imaging, may improve the rate of surgical success of posterior cortex epilepsy at paediatric age. PMID:24853765

  15. Shape-specific preparatory activity mediates attention to targets in human visual cortex.

    PubMed

    Stokes, Mark; Thompson, Russell; Nobre, Anna C; Duncan, John

    2009-11-17

    The mechanisms of attention prioritize sensory input for efficient perceptual processing. Influential theories suggest that attentional biases are mediated via preparatory activation of task-relevant perceptual representations in visual cortex, but the neural evidence for a preparatory coding model of attention remains incomplete. In this experiment, we tested core assumptions underlying a preparatory coding model for attentional bias. Exploiting multivoxel pattern analysis of functional neuroimaging data obtained during a non-spatial attention task, we examined the locus, time-course, and functional significance of shape-specific preparatory attention in the human brain. Following an attentional cue, yet before the onset of a visual target, we observed selective activation of target-specific neural subpopulations within shape-processing visual cortex (lateral occipital complex). Target-specific modulation of baseline activity was sustained throughout the duration of the attention trial and the degree of target specificity that characterized preparatory activation patterns correlated with perceptual performance. We conclude that top-down attention selectively activates target-specific neural codes, providing a competitive bias favoring task-relevant representations over competing representations distributed within the same subregion of visual cortex. PMID:19887644

  16. Voxel-based analysis of MRI detects abnormal visual cortex in children and adults with amblyopia.

    PubMed

    Mendola, Janine D; Conner, Ian P; Roy, Anjali; Chan, Suk-Tak; Schwartz, Terry L; Odom, J Vernon; Kwong, Kenneth K

    2005-06-01

    Amblyopia, sometimes called "lazy eye," is a relatively common developmental visual disorder well characterized behaviorally; however, the neural substrates associated with amblyopia in humans remain unclear. We hypothesized that abnormalities in the cerebral cortex of subjects with amblyopia exist, possibly as a result of experience-dependent neuronal plasticity. Anatomic magnetic resonance imaging (MRI) and psychophysical vision testing was carried out on 74 subjects divided into two age ranges, 7-12 years and 18-35 years, and three diagnoses, strabismic amblyopia, anisometropic amblyopia, and normal vision. We report a behavioral impairment in contrast sensitivity for subjects with amblyopia, consistent with previous reports. When the high-resolution MRI brain images were analyzed quantitatively with optimized voxel-based morphometry, results indicated that adults and children with amblyopia have decreased gray matter volume in visual cortical regions, including the calcarine sulcus, known to contain primary visual cortex. This finding was confirmed with a separate region-of-interest analysis. For the children with amblyopia, additional gray matter reductions in parietal-occipital areas and ventral temporal cortex were detected, consistent with recent reports that amblyopia can result in spatial location and object processing deficits. These data are the first to provide possible neuroanatomic bases for the loss of binocularity and visual sensitivity in children and adults with amblyopia. PMID:15846772

  17. Eccentricity mapping of the human visual cortex to evaluate temporal dynamics of functional T1? mapping.

    PubMed

    Heo, Hye-Young; Wemmie, John A; Johnson, Casey P; Thedens, Daniel R; Magnotta, Vincent A

    2015-07-01

    Recent experiments suggest that T1 relaxation in the rotating frame (T1?) is sensitive to metabolism and can detect localized activity-dependent changes in the human visual cortex. Current functional magnetic resonance imaging (fMRI) methods have poor temporal resolution due to delays in the hemodynamic response resulting from neurovascular coupling. Because T1? is sensitive to factors that can be derived from tissue metabolism, such as pH and glucose concentration via proton exchange, we hypothesized that activity-evoked T1? changes in visual cortex may occur before the hemodynamic response measured by blood oxygenation level-dependent (BOLD) and arterial spin labeling (ASL) contrast. To test this hypothesis, functional imaging was performed using T1?, BOLD, and ASL in human participants viewing an expanding ring stimulus. We calculated eccentricity phase maps across the occipital cortex for each functional signal and compared the temporal dynamics of T1? versus BOLD and ASL. The results suggest that T1? changes precede changes in the two blood flow-dependent measures. These observations indicate that T1? detects a signal distinct from traditional fMRI contrast methods. In addition, these findings support previous evidence that T1? is sensitive to factors other than blood flow, volume, or oxygenation. Furthermore, they suggest that tissue metabolism may be driving activity-evoked T1? changes. PMID:25966957

  18. Manganese-enhanced MRI visualizes V1 in the non-human primate visual cortex.

    PubMed

    Bock, Nicholas A; Kocharyan, Ara; Silva, Afonso C

    2009-08-01

    MRI at 7 Tesla has been used to investigate the accumulation of manganese in the occipital cortex of common marmoset monkeys (Callithrix jacchus) after administering four fractionated injections of 30 mg/kg MnCl(2) . 4H(2)O in the tail vein. We found a statistically significant decrease in T(1) in the primary (V1) and secondary (V2) areas of the visual cortex caused by an accumulation of manganese. The larger T(1) shortening in V1 (DeltaT(1) = 640 ms) relative to V2 (DeltaT(1) = 490 ms) allowed us to robustly detect the V1/V2 border in vivo using heavily T(1)-weighted MRI. Furthermore, the dorso-medial (DM) and middle-temporal (MT) areas of the visual pathway could be identified by their T(1)-weighted enhancement. We showed by comparison to histological sections stained for cytochrome oxidase (CO) activity that the extent of V1 is accurately identified throughout the visual cortex by manganese-enhanced MRI (MEMRI). This provides a means of visualizing functional cortical regions in vivo and could be used in longitudinal studies of phenomena such as cortical plasticity, and for non-destructive localization of cortical regions to guide in the implementation of functional techniques. PMID:19322808

  19. LOC401317, a p53-Regulated Long Non-Coding RNA, Inhibits Cell Proliferation and Induces Apoptosis in the Nasopharyngeal Carcinoma Cell Line HNE2

    PubMed Central

    Gong, Zhaojian; Zhang, Shanshan; Zeng, Zhaoyang; Wu, Hanjiang; Yang, Qian; Xiong, Fang; Shi, Lei; Yang, Jianbo; Zhang, Wenling; Zhou, Yanhong; Zeng, Yong; Li, Xiayu; Xiang, Bo; Peng, Shuping; Zhou, Ming; Li, Xiaoling; Tan, Ming; Li, Yong; Xiong, Wei; Li, Guiyuan

    2014-01-01

    Recent studies have revealed that long non-coding RNAs participate in all steps of cancer initiation and progression by regulating protein-coding genes at the epigenetic, transcriptional, and post-transcriptional levels. Long non-coding RNAs are in turn regulated by other genes, forming a complex regulatory network. The regulation networks between the p53 tumor suppressor and these RNAs in nasopharyngeal carcinoma remains unclear. The aims of this study were to investigate the regulatory roles of the TP53 gene in regulating long non-coding RNA expression profiles and to study the function of a TP53-regulated long non-coding RNA (LOC401317) in the nasopharyngeal carcinoma cell line HNE2. Long non-coding RNA expression profiling indicated that 133 long non-coding RNAs were upregulated in the human NPC cell line HNE2 cells following TP53 overexpression, while 1057 were downregulated. Among these aberrantly expressed long non-coding RNAs, LOC401317 was the most significantly upregulated one. Further studies indicated that LOC401317 is directly regulated by p53 and that ectopic expression of LOC401317 inhibits HNE2 cell proliferation in vitro and in vivo by inducing cell cycle arrest and apoptosis. LOC401317 inhibited cell cycle progression by increasing p21 expression and decreasing cyclin D1 and cyclin E1 expression and promoted apoptosis through the induction of poly(ADP-ribose) polymerase and caspase-3 cleavage. Collectively, these results suggest that LOC401317 is directly regulated by p53 and exerts antitumor effects in HNE2 nasopharyngeal carcinoma cells. PMID:25422887

  20. Detection of thiopurine methyltransferase activity in lysed red blood cells by means of lab-on-a-chip surface enhanced Raman spectroscopy (LOC-SERS).

    PubMed

    März, Anne; Mönch, Bettina; Rösch, Petra; Kiehntopf, Michael; Henkel, Thomas; Popp, Jürgen

    2011-07-01

    In this contribution, the great potential of surface enhanced Raman spectroscopy (SERS) in a lab-on-a-chip (LOC) device for the detection of analyte molecules in a complex environment is demonstrated. Using LOC-SERS, the enzyme activity of thiopurine S-methyltransferase (TPMT) is analysed and identified in lysed red blood cells. The conversion of 6-mercaptopurine to 6-methylmercaptopurine catalysed by TPMT is observed as it gives evidence for the enzyme activity. Being able to determine the TPMT activity before starting a treatment using 6-mercaptopurine, an optimized dosage can be applied to each patient and serious toxicity appearing within thiopurine treatment will be prevented. PMID:21359568

  1. Chemosensory Learning in the Cortex

    PubMed Central

    Rolls, Edmund T.

    2011-01-01

    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 flavor. Rapid reversal of this learning can occur using a rule-based learning system that can be reset when an expected taste or flavor 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 of 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 is 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. PMID:21954379

  2. Binary Coding in Auditory Cortex

    Microsoft Academic Search

    Michael Deweese; Anthony M. Zador

    2002-01-01

    Neurons are often assumed to operate in a highly unreliable manner: a neuron can signal the same stimulus with a variable number of action potentials. However, much of the experimental evidence supporting this view was obtained in the visual cortex. We have, therefore, assessed trial-to-trial variability in the auditory cortex of the rat. To ensure single-unit isolation, we used cell-attached

  3. MRI volumetry of prefrontal cortex

    NASA Astrophysics Data System (ADS)

    Sheline, Yvette I.; Black, Kevin J.; Lin, Daniel Y.; Pimmel, Joseph; Wang, Po; Haller, John W.; Csernansky, John G.; Gado, Mokhtar; Walkup, Ronald K.; Brunsden, Barry S.; Vannier, Michael W.

    1995-05-01

    Prefrontal cortex volumetry by brain magnetic resonance (MR) is required to estimate changes postulated to occur in certain psychiatric and neurologic disorders. A semiautomated method with quantitative characterization of its performance is sought to reliably distinguish small prefrontal cortex volume changes within individuals and between groups. Stereological methods were tested by a blinded comparison of measurements applied to 3D MR scans obtained using an MPRAGE protocol. Fixed grid stereologic methods were used to estimate prefrontal cortex volumes on a graphic workstation, after the images are scaled from 16 to 8 bits using a histogram method. In addition images were resliced into coronal sections perpendicular to the bicommissural plane. Prefrontal cortex volumes were defined as all sections of the frontal lobe anterior to the anterior commissure. Ventricular volumes were excluded. Stereological measurement yielded high repeatability and precision, and was time efficient for the raters. The coefficient of error was cortex boundaries on 3D images was critical to obtaining accurate measurements. MR prefrontal cortex volumetry by stereology can yield accurate and repeatable measurements. Small frontal lobe volume reductions in patients with brain disorders such as depression and schizophrenia can be efficiently assessed using this method.

  4. Cue-Invariant Networks for Figure and Background Processing in Human Visual Cortex

    PubMed Central

    Appelbaum, L. Gregory; Wade, Alex R.; Vildavski, Vladimir Y.; Pettet, Mark W.; Norcia, Anthony M.

    2009-01-01

    Lateral occipital cortical areas are involved in the perception of objects, but it is not clear how these areas interact with first tier visual areas. Using synthetic images portraying a simple texture-defined figure and an electrophysiological paradigm that allows us to monitor cortical responses to figure and background regions separately, we found distinct neuronal networks responsible for the processing of each region. The figure region of our displays was tagged with one temporal frequency (3.0 Hz) and the background region with another (3.6 Hz). Spectral analysis was used to separate the responses to the two regions during their simultaneous presentation. Distributed source reconstructions were made by using the minimum norm method, and cortical current density was measured in a set of visual areas defined on retinotopic and functional criteria with the use of functional magnetic resonance imaging. The results of the main experiments, combined with a set of control experiments, indicate that the figure region, but not the background, was routed preferentially to lateral cortex. A separate network extending from first tier through more dorsal areas responded preferentially to the background region. The figure-related responses were mostly invariant with respect to the texture types used to define the figure, did not depend on its spatial location or size, and mostly were unaffected by attentional instructions. Because of the emergent nature of a segmented figure in our displays, feedback from higher cortical areas is a likely candidate for the selection mechanism by which the figure region is routed to lateral occipital cortex. PMID:17093091

  5. PAPER www.rsc.org/loc | Lab on a Chip Programmable assembly of a metabolic pathway enzyme in a pre-packaged

    E-print Network

    Rubloff, Gary W.

    PAPER www.rsc.org/loc | Lab on a Chip Programmable assembly of a metabolic pathway enzyme in a pre report a biofunctionalization strategy for the assembly of catalytically active enzymes within and temporally defined sites. The enzyme of a bacterial metabolic pathway, S-adenosylhomocysteine nucleosidase

  6. Vasopressin-induced constriction of the isolated rat occipital artery is segment-dependent

    PubMed Central

    Chelko, Stephen P.; Schmiedt, Chad W.; Lewis, Tristan H.; Lewis, Stephen J.; Robertson, Tom P.

    2014-01-01

    Background Circulating factors delivered to the nodose ganglion (NG) by the occipital artery (OA) have shown to affect vagal afferent activity, and thus the contractile state of the OA may influence blood flow to the NG. Methods OA were isolated and bisected into proximal and distal segments, relative to the external carotid artery. Results Bisection, highlighted stark differences between maximal contractile responses and OA sensitivity. Specifically, maximum responses to vasopressin and the V1 receptor agonist, were significantly higher in distal than proximal segments. Distal segments were significantly more sensitive to 5-HT and the 5-HT2 receptor agonist than proximal segments. AT2, V2 and 5-HT1B/1D receptor agonists did not elicit vascular responses. Additionally, AT1 receptor agonists elicited mild, yet not significantly different maximal responses between segments. Conclusion The results of this study are consistent with contractile properties of rat OA being mediated via AT1, V1 and 5-HT2 receptors, and are dependent upon the OA segment. Furthermore, vasopressin-induced constriction of the OA, regardless of a bolus dose or a first and second concentration response curve retained this unique segmental difference and therefore we hypothesize this may be a pathophysiological response in the regulation of blood flow through the OA. PMID:24192548

  7. Successful Treatment of Occipital Neuralgia with Implantable Peripheral Nerve Stimulation in a Pacemaker-Dependent Patient

    PubMed Central

    Chaiban, Gassan; Tolba, Reda; Eissa, Hazem; Lirette, Lesley Smallwood; Almualim, Mohammed; Malaty, Adham; Atallah, Joseph

    2014-01-01

    Background Peripheral nerve stimulation has been used to treat patients with occipital nerve–related chronic headaches who have been unsuccessful with less invasive therapeutic approaches. Patients with pacemaker-dependent cardiac conduction abnormalities require unique consideration prior to the implantation of peripheral nerve stimulators because the placement of the devices may lead to failure of the systems secondary to electromagnetic interference or crosstalk between the devices. Case Report An 86-year-old female who suffered from chronic right-sided cervicogenic headaches and neck pain had received only temporary relief from previous treatments. Additional comorbidities included longstanding pacemaker-dependent atrioventricular node conduction disease. Because the extent to which nerve stimulators electrically interact with pacemakers is unclear, we tunneled the leads to the lumbar region of the back and placed the generator on the contralateral side to the pacemaker to minimize the chance that the 2 devices would interfere. The patient has remained pain free for 1 year since implantation. Conclusion Although no current published trials evaluate the degree of interference between medical devices, case reports increasingly suggest that simultaneous implantation of a spinal cord stimulator and pacemaker is safe as long as precautions are taken and the devices are checked periodically, particularly when the devices are adjusted. PMID:24688344

  8. Experienced Mindfulness Meditators Exhibit Higher Parietal-Occipital EEG Gamma Activity during NREM Sleep

    PubMed Central

    Ferrarelli, Fabio; Smith, Richard; Dentico, Daniela; Riedner, Brady A.; Zennig, Corinna; Benca, Ruth M.; Lutz, Antoine; Davidson, Richard J.; Tononi, Giulio

    2013-01-01

    Over the past several years meditation practice has gained increasing attention as a non-pharmacological intervention to provide health related benefits, from promoting general wellness to alleviating the symptoms of a variety of medical conditions. However, the effects of meditation training on brain activity still need to be fully characterized. Sleep provides a unique approach to explore the meditation-related plastic changes in brain function. In this study we performed sleep high-density electroencephalographic (hdEEG) recordings in long-term meditators (LTM) of Buddhist meditation practices (approximately 8700 mean hours of life practice) and meditation naive individuals. We found that LTM had increased parietal-occipital EEG gamma power during NREM sleep. This increase was specific for the gamma range (25–40 Hz), was not related to the level of spontaneous arousal during NREM and was positively correlated with the length of lifetime daily meditation practice. Altogether, these findings indicate that meditation practice produces measurable changes in spontaneous brain activity, and suggest that EEG gamma activity during sleep represents a sensitive measure of the long-lasting, plastic effects of meditative training on brain function. PMID:24015304

  9. Anatomical study of the occipital sinus using contrast-enhanced magnetic resonance venography.

    PubMed

    Kobayashi, Keiko; Suzuki, Masayuki; Ueda, Fumiaki; Matsui, Osamu

    2006-06-01

    The frequency and anatomical features of the occipital sinus (OS) were analyzed in this study by contrast-enhanced magnetic resonance venography (MRV) with enhanced fast gradient echo three-dimensional (EFGRE3D) and we discuss the clinical usefulness of this method. The study included 555 patients who underwent contrast-enhanced MRV with EFGRE3D, and maximum intensity projection (MIP), multiplanar reformation (MPR) and multiprojection volume reconstruction (MPVR) images were obtained for the regions of interest. The frequency, size and communication of the OS with other vessels were assessed. The OS was identified in 209 of the 555 patients (37.7%). There were no statistically significant sex-related differences. The OS was observed less frequently in subjects younger than 50 years. Cranially and/or caudally, some OS were separated and communicated with multiple vessels. In five patients, the straight sinus (StS) communicated directly with the OS and not with the other sinuses; in two patients, the StS communicated with veins other than the OS only via small anastomotic veins. Many morphological differences in the OS can be seen. In addition, some OS function as the main drainage route of the intracranial veins instead of the transverse sinus or sigmoid sinus. In addition to MIP, detailed examination by MPR and MPVR is required for the preoperative evaluation of posterior cranial fossa lesions. PMID:16758154

  10. Cultural differences in the lateral occipital complex while viewing incongruent scenes

    PubMed Central

    Yang, Yung-Jui; Goh, Joshua; Hong, Ying-Yi; Park, Denise C.

    2010-01-01

    Converging behavioral and neuroimaging evidence indicates that culture influences the processing of complex visual scenes. Whereas Westerners focus on central objects and tend to ignore context, East Asians process scenes more holistically, attending to the context in which objects are embedded. We investigated cultural differences in contextual processing by manipulating the congruence of visual scenes presented in an fMR-adaptation paradigm. We hypothesized that East Asians would show greater adaptation to incongruent scenes, consistent with their tendency to process contextual relationships more extensively than Westerners. Sixteen Americans and 16 native Chinese were scanned while viewing sets of pictures consisting of a focal object superimposed upon a background scene. In half of the pictures objects were paired with congruent backgrounds, and in the other half objects were paired with incongruent backgrounds. We found that within both the right and left lateral occipital complexes, Chinese participants showed significantly greater adaptation to incongruent scenes than to congruent scenes relative to American participants. These results suggest that Chinese were more sensitive to contextual incongruity than were Americans and that they reacted to incongruent object/background pairings by focusing greater attention on the object. PMID:20083532

  11. First-drug treatment failures in 42 Turkish children with idiopathic childhood occipital epilepsies

    PubMed Central

    Incecik, Faruk; Herguner, Ozlem M.; Altunbasak, Sakir

    2015-01-01

    Background: The early and late benign occipital epilepsies of childhood (BOEC) are described as two discrete electro-clinical syndromes, eponymously known as Panayiotopoulos and Gastaut syndromes. The purpose of this study was to identify predictors of failure to respond to the initial antiepileptic drug (AED). Materials and Methods: A total of 42 children with BOEC were enrolled. Predictive factors were analyzed by survival methods. Results: Among the 42, 25 patients (59.5%) were boys and 17 (40.5%) were girls and the mean age at the seizure onset was 7.46 ± 2.65 years (4–14 years). Of the 42 patients, 34 (81.0%) were treated relatively successfully with the first AED treatment, and 8 (19.0%) were not responded initial AED treatment. There was no correlation between response to initial AED treatment and sex, consanguinity, epilepsy history of family, age of seizure onset, frequency of seizures, history of status epilepticus, duration of starting first treatment, findings on electroencephalogram. However, history of febrile seizure and type of BOEC were significantly associated with failure risk. Conclusions: Factors predicting failure to respond to the AED were history of febrile seizure and type of BOEC in children with BOEC.

  12. Probabilistic and single-subject retinotopic maps reveal the topographic organization of face patches in the macaque cortex.

    PubMed

    Janssens, Thomas; Zhu, Qi; Popivanov, Ivo D; Vanduffel, Wim

    2014-07-30

    Face perception is crucial to survival among social primates. It has been suggested that a group of extrastriate cortical regions responding more strongly to faces than to nonface objects is critical for face processing in primates. It is generally assumed that these regions are not retinotopically organized, as with human face-processing areas, showing foveal bias but lacking any organization with respect to polar angle. Despite many electrophysiological studies targeting monkey face patches, the retinotopic organization of these patches remains largely unclear. We have examined the relationship between cortical face patches and the topographic organization of extrastriate cortex using biologically relevant, phase-encoded retinotopic mapping stimuli in macaques. Single-subject fMRI results indicated a gradual shift from highly retinotopic to no topographic organization from posterior to anterior face patches in inferotemporal cortex. We also constructed a probabilistic retinotopic atlas of occipital and ventral extrastriate visual cortex. By comparing this probabilistic map to the locations of face patches at the group level, we showed that a previously identified posterior lateral temporal face patch (PL) is located within the posterior inferotemporal dorsal (PITd) retinotopic area. Furthermore, we identified a novel face patch posterior PL, which is located in retinotopically organized transitional area V4 (V4t). Previously published coordinates of human PITd coincide with the group-level occipital face area (OFA), according to a probabilistic map derived from a large population, implying a potential correspondence between monkey PL/PITd and human OFA/PITd. Furthermore, the monkey middle lateral temporal face patch (ML) shows consistent foveal biases but no obvious polar-angle structure. In contrast, middle fundus temporal (MF), anterior temporal and prefrontal monkey face patches lacked topographic organization. PMID:25080579

  13. Differential rearing effects on rat visual cortex synapses. III. Neuronal and glial nuclei, boutons, dendrites, and capillaries.

    PubMed

    Sirevaag, A M; Greenough, W T

    1987-10-27

    Morphological measures of neurons, astrocytes, oligodendrocytes, presynaptic boutons, dendrites and capillaries were examined in the upper 4 layers of occipital cortex in rats reared for 30 days postweaning in complex (EC), social (SC) or individual cage (IC) environments. EC rats had a lower numerical density of neuronal nuclei with a comparable volume fraction to SC and IC rats. The volume fraction of astrocyte and oligodendrocyte nuclei was significantly greater for EC rats than IC littermates, and IC rats also had more synapses and neurons/micron3 of glial nuclei. Environmental groups did not differ in the numerical density of presynaptic boutons but the number of boutons per neuron was greater in EC than in IC or SC rats. This result parallels the findings that EC rats have more synapses per neuron than IC rats. Electron microscopic estimates of dendritic volume fraction confirmed estimates from Golgi-impregnated neurons that there is more dendrite per neuron in the occipital cortex of EC rats than IC or SC rats. EC rats also had a larger capillary volume than SC or IC and these capillaries were closer together and had fewer synapses/micron3 of capillary in ECs. Another indicator of metabolic activity, mitochondria volume per neuron, gave similar results with ECs having a greater volume than ICs and SCs intermediate. These results indicate that not only are there more synapses per neuron in the visual cortex of rats from more complex environments but also that the brain appears to adjust to the metabolic requirements of its synapses or neurons, in terms of vascular, mitochondrial and glial support. PMID:3676831

  14. HybridGO-Loc: Mining Hybrid Features on Gene Ontology for Predicting Subcellular Localization of Multi-Location Proteins

    PubMed Central

    Wan, Shibiao; Mak, Man-Wai; Kung, Sun-Yuan

    2014-01-01

    Protein subcellular localization prediction, as an essential step to elucidate the functions in vivo of proteins and identify drugs targets, has been extensively studied in previous decades. Instead of only determining subcellular localization of single-label proteins, recent studies have focused on predicting both single- and multi-location proteins. Computational methods based on Gene Ontology (GO) have been demonstrated to be superior to methods based on other features. However, existing GO-based methods focus on the occurrences of GO terms and disregard their relationships. This paper proposes a multi-label subcellular-localization predictor, namely HybridGO-Loc, that leverages not only the GO term occurrences but also the inter-term relationships. This is achieved by hybridizing the GO frequencies of occurrences and the semantic similarity between GO terms. Given a protein, a set of GO terms are retrieved by searching against the gene ontology database, using the accession numbers of homologous proteins obtained via BLAST search as the keys. The frequency of GO occurrences and semantic similarity (SS) between GO terms are used to formulate frequency vectors and semantic similarity vectors, respectively, which are subsequently hybridized to construct fusion vectors. An adaptive-decision based multi-label support vector machine (SVM) classifier is proposed to classify the fusion vectors. Experimental results based on recent benchmark datasets and a new dataset containing novel proteins show that the proposed hybrid-feature predictor significantly outperforms predictors based on individual GO features as well as other state-of-the-art predictors. For readers' convenience, the HybridGO-Loc server, which is for predicting virus or plant proteins, is available online at http://bioinfo.eie.polyu.edu.hk/HybridGoServer/. PMID:24647341

  15. Atlanto-axial approach for cervical myelography in a Thoroughbred horse with complete fusion of the atlanto-occipital bones.

    PubMed

    Aleman, Monica; Dimock, Abigail N; Wisner, Erik R; Prutton, Jamie W; Madigan, John E

    2014-11-01

    A 2-year-old Thoroughbred gelding with clinical signs localized to the first 6 spinal cord segments (C1 to C6) had complete fusion of the atlanto-occipital bones which precluded performing a routine myelogram. An ultrasound-assisted myelogram at the intervertebral space between the atlas and axis was successfully done and identified a marked extradural compressive myelopathy at the level of the atlas and axis, and axis and third cervical vertebrae. PMID:25392550

  16. Atlanto-axial approach for cervical myelography in a Thoroughbred horse with complete fusion of the atlanto-occipital bones

    PubMed Central

    Aleman, Monica; Dimock, Abigail N.; Wisner, Erik R.; Prutton, Jamie W.; Madigan, John E.

    2014-01-01

    A 2-year-old Thoroughbred gelding with clinical signs localized to the first 6 spinal cord segments (C1 to C6) had complete fusion of the atlanto-occipital bones which precluded performing a routine myelogram. An ultrasound-assisted myelogram at the intervertebral space between the atlas and axis was successfully done and identified a marked extradural compressive myelopathy at the level of the atlas and axis, and axis and third cervical vertebrae. PMID:25392550

  17. Geometry of the articular facets of the lateral atlanto-axial joints in the case of occipitalization.

    PubMed

    Ryniewicz, A M; Skrzat, J; Ryniewicz, A; Ryniewicz, W; Walocha, J

    2010-08-01

    This study investigates if atlanto-occipital fusion affects the size and geometrical configuration of the articular facets of the atlanto-axial joint. Morphometric analysis was performed on the male adult skull, the occipital bone of which is assimilated with the first cervical vertebrae (the atlas). The perimeter, Feret's diameter, surface area, and circularity of the inferior articular fa-cets were measured. However, we did not observe significant bilateral differences in size of the inferior articular facets of the assimilated atlas compared to normal first cervical vertebrae. Geometrical conformation of the articular facets of the atlas and axis was assessed using a coordinate measuring machine (PMM - 12106, Leitz). The results obtained from this machine indicated that the inferior articular facets of the assimilated atlas presented asymmetrical orientation compared to the normal anatomy of the atlas. Hence, in the case of occipitalization, the gap between the articulating facets of the atlas and the axis was measured to be greater than in the normal atlanto-axial joint. Computer assisted tomography was applied to visualise the anatomical relationship between the inferior articular facets of the assimilated atlas and the corresponding facets located on the axis. In this case, radiographic examination revealed that the bilaterally articulating facets (inferior and superior) showed disproportion in their adjustment within the lateral atlanto-axial joints. Thus, we concluded that the fusion of the atlas with the occipital bone altered the geometry of the inferior articular facets of the atlas and influenced the orientation of the superior articular facets of the axis. PMID:21154284

  18. Occipital lobe epilepsy secondary to Posterior Reversible Encephalopathy Syndrome (PRES) during a post-partum eclampsia in Mali (West Africa)

    PubMed Central

    2013-01-01

    Background Eclampsia is known to cause posterior reversible encephalopathy syndrome (PRES) that is often associated with an extensive neurovascular damage affecting preferably posterior regions, often leading to reversible cortical blindness. In spite the magnitude of these lesions, post eclamptic symptomatic epilepsy is rare. We therefore report a case of symptomatic occipital lobe epilepsy secondary to PRES. Case presentation A 39-year-old female right handed teacher who presented with headache of progressive onset, phosphenes, rapid decline of visual acuity to blindness, vomiting, repeated generalized tonic-clonic seizures followed by altered consciousness and very high blood pressure (HBP) of 240/120 mmHg, all of which started about 12 hours following a normal delivery. Nine months later, the patient presented with paroxysmal visual symptoms predominating in the right visual field followed by partial tonic clonic seizures with secondary generalization and recurrence of partial occipital lobe seizures. The pathophysiologic mechanism of irreversible tissue damage during PRES syndrome could result from a combination of events including the delay for early treatment, inadequate antihypertensive drugs that could worsen the brain damage by hypo perfusion, inadequate or delayed treatment for seizures or status epilepticus. Conclusion Despite its high incidence in the third world, eclampsia is not a usual cause of epilepsy. Our case is the first description of post eclamptic occipital lobe epilepsy in Africa. With this report, we draw practitioners’ attention on this rare complication. PMID:23941365

  19. Relationship between the morphology of the atlanto-occipital joint and the radiographic results in patients with atlanto-axial subluxation due to rheumatoid arthritis

    Microsoft Academic Search

    Haku Iizuka; Yasunori Sorimachi; Tsuyoshi Ara; Masahiro Nishinome; Takashi Nakajima; Yoichi Iizuka; Kenji Takagishi

    2008-01-01

    The upper cervical spine is a common focus of destruction from rheumatoid arthritis (RA). Atlanto-axial subluxation (AAS)\\u000a presents with marked frequency among patients with instability. However, there are occasional patients who show no motion\\u000a between the occipital bone and atlas on a dynamic cervical radiograph in AAS patients. This study investigated the morphology\\u000a of the atlanto-occipital joint (AOJ) in AAS

  20. A rare case of atlantooccipital dissociation in the context of occipitalization of the atlas, with a 2-year follow-up: case report.

    PubMed

    Chaudhary, Navjot; Wang, Bill H; Gurr, Kevin R; Bailey, Stewart I; Bailey, Christopher S

    2013-02-01

    Atlantooccipital dislocation (AOD) is a rare and often fatal injury. In cases of survival, residual deficits are severe and often include cranial nerve palsy, quadriplegia, or respiratory issues. Occipitalization is defined as partial or complete congenital fusion of the occiput to the atlas and is exceptionally rare. The authors present a rare case of AOD superimposed on a congenital occipitalization of the atlas. This 39-year-old man had AOD following a motor vehicle collision. On examination, his overall motor score on the American Spinal Injury Association scale was 5/100, and his rectal tone was absent. Computed tomography demonstrated AOD in an area of occipitalization. Magnetic resonance imaging revealed ligamentous injury leading to C1-2 instability. Intervention included occipital cervical instrumentation fusion from the occiput to C-3. Six months postoperatively, imaging revealed fusion of the graft and consolidation of the fractured occipitalization. At the 2-year follow-up, the patient's strength was 3/5 for wrist extension and handgrip on the right side and full strength in the rest of the myotomes. Bladder and bowel function was also normalized. A high-velocity collision led to disruption of the atlantooccipital ligaments and fracture of the occipitalized lateral masses in this patient. Internal fixation and fusion led to good fusion postoperatively. Occipitalization probably led to abnormal joint mechanics at the C1-occiput junction, which might have altered the amount of force required to fracture the occipitalization and produce AOD. This difference may partially account for the favorable neurological outcome in the featured patient compared with traditional cases of AOD. PMID:23198835

  1. Effect of Prenatal Protein Malnutrition on Long-Term Potentiation and BDNF Protein Expression in the Rat Entorhinal Cortex after Neocortical and Hippocampal Tetanization

    PubMed Central

    Hernández, Alejandro; Burgos, Héctor; Mondaca, Mauricio; Barra, Rafael; Núñez, Héctor; Pérez, Hernán; Soto-Moyano, Rubén; Sierralta, Walter; Fernández, Victor; Olivares, Ricardo; Valladares, Luis

    2008-01-01

    Reduction of the protein content from 25 to 8% casein in the diet of pregnant rats results in impaired neocortical long-term potentiation (LTP) of the offspring together with lower visuospatial memory performance. The present study was aimed to investigate whether this type of maternal malnutrition could result in modification of plastic capabilities of the entorhinal cortex (EC) in the adult progeny. Unlike normal eutrophic controls, 55–60-day-old prenatally malnourished rats were unable to develop LTP in the medial EC to tetanizing stimulation delivered to either the ipsilateral occipital cortex or the CA1 hippocampal region. Tetanizing stimulation of CA1 also failed to increase the concentration of brain-derived neurotrophic factor (BDNF) in the EC of malnourished rats. Impaired capacity of the EC of prenatally malnourished rats to develop LTP and to increase BDNF levels during adulthood may be an important factor contributing to deficits in learning performance having adult prenatally malnourished animals. PMID:18604298

  2. The functions of the orbitofrontal cortex

    Microsoft Academic Search

    Edmund T. Rolls

    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 of objects from the temporal lobe cortical visual

  3. The functions of the orbitofrontal cortex

    Microsoft Academic Search

    Edmund T. Rolls

    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 of objects from the temporal lobe cortical visual

  4. The Functions of the Orbitofrontal Cortex

    ERIC Educational Resources Information Center

    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…

  5. Fractures of the occipital condyle clinical spectrum and course in eight patients

    PubMed Central

    Krüger, Antonio; Oberkircher, Ludwig; Frangen, Thomas; Ruchholtz, Steffen; Kühne, Christian; Junge, Andreas

    2013-01-01

    Introduction: Occipital condyle fractures (OCFs) are considered to be rare injuries. OCFs are now diagnosed more often because of the widespread use of computed tomography. Our aim is to report the incidence, treatment and long term outcome of 8 patients with OCFs. Materials and Methods: All patients presenting with multiple trauma from 1993 to 2006 were analyzed retrospectively. Characteristics and course of the treatment were evaluated. Follow-up was performed after 11,7 years (range 5,9 to 19,3 years). Results: Nine cases of OCF in 8 patients were identified. All injuries resulted from high velocity trauma. The average scores on the ISS Scale were 39,6 (24-75) and 7,3 (3-15) on the GCS. According to Anderson's classification, 5 cases of Type III and 4 cases of Type I fractures were identified. According to Tuli's classification, 5 cases of Type IIA and 4 cases of Type I were found. Indications for immobilization with the halo-vest were type III injuries according to Anderson's classification or Tuli's type IIA injuries, respectively. Patients with Tuli's type I injuries were treated with a Philadelphia collar for 6 weeks. In one patient with initial complete tetraplegia and one with incomplete neurological deficits the final follow-up neurologic examination showed no neurological impairment at all (Frankel-grade A to E, respectively B to E). At follow-up, 3 patients were asymptomatic. Four patients suffered from mild pain when turning their head, pain medication was necessary in one case only. Discussion: OCF's are virtually undetectable using conventional radiography. In cases of high velocity, cranio-cervical trauma or impaired consciousness, high resolution CT-scans of the craniocervical junction must be performed. We suggest immobilization using a halo device for type III injuries according to Anderson's classification or Tuli's type IIa injuries, respectively. Patients with Tuli's type I injuries should be treated with a Philadelphia collar. PMID:24744561

  6. The left inferior fronto-occipital fasciculus subserves language semantics: a multilevel lesion study.

    PubMed

    Almairac, Fabien; Herbet, Guillaume; Moritz-Gasser, Sylvie; de Champfleur, Nicolas Menjot; Duffau, Hugues

    2015-07-01

    Consequential works in cognitive neuroscience have led to the formulation of an interactive dual-stream model of language processing: the dorsal stream may process the phonological aspects of language, whereas the ventral stream may process the semantic aspects of language. While it is well-accepted that the dorsal route is subserved by the arcuate fasciculus, the structural connectivity of the semantic ventral stream is a matter of dispute. Here we designed a longitudinal study to gain new insights into this central but controversial question. Thirty-one patients harboring a left diffuse low-grade glioma-a rare neurological condition that infiltrates preferentially white matter associative pathways-were assessed with a prototypical task of language (i.e. verbal fluency) before and after surgery. All were operated under local anesthesia with a cortical and subcortical brain mapping-enabling to identify and preserve eloquent structures for language. We performed voxel-based lesion-symptom (VLSM) analyses on pre- and postoperative behavioral data. Preoperatively, we found a significant relationship between semantic fluency scores and the white matter fibers shaping the ventro-lateral connectivity (P < 0.05 corrected). The statistical map was found to substantially overlap with the spatial position of the inferior fronto-occipital fasciculus (IFOF) (37.7 %). Furthermore, a negative correlation was observed between semantic fluency scores and the infiltration volumes in this fasciculus (r = -0.4, P = 0.029). Postoperatively, VLSM analyses were inconclusive. Taken as a whole and when combined with the literature data, our findings strengthen the view that the IFOF plays an essential role in semantic processing and may subserve the direct ventral pathway of language. PMID:24744151

  7. Population coding in somatosensory cortex

    Microsoft Academic Search

    Rasmus S Petersen; Stefano Panzeri; Mathew E Diamond

    2002-01-01

    Computational analyses have begun to elucidate which components of somatosensory cortical population activity may encode basic stimulus features. Recent results from rat barrel cortex suggest that the essence of this code is not synergistic spike patterns, but rather the precise timing of single neuron's first post-stimulus spikes. This may form the basis for a fast, robust population code.

  8. The insular cortex: a review.

    PubMed

    Nieuwenhuys, Rudolf

    2012-01-01

    The human insular cortex forms a distinct, but entirely hidden lobe, situated in the depth of the Sylvian fissure. Here, we first review the recent literature on the connectivity and the functions of this structure. It appears that this small lobe, taking up less than 2% of the total cortical surface area, receives afferents from some sensory thalamic nuclei, is (mostly reciprocally) connected with the amygdala and with many limbic and association cortical areas, and is implicated in an astonishingly large number of widely different functions, ranging from pain perception and speech production to the processing of social emotions. Next, we embark on a long, adventurous journey through the voluminous literature on the structural organization of the insular cortex. This journey yielded the following take-home messages: (1) The meticulous, but mostly neglected publications of Rose (1928) and Brockhaus (1940) are still invaluable for our understanding of the architecture of the mammalian insular cortex. (2) The relation of the insular cortex to the adjacent claustrum is neither ontogenetical nor functional, but purely topographical. (3) The insular cortex has passed through a spectacular progressive differentiation during hominoid evolution, but the assumption of Craig (2009) that the human anterior insula has no homologue in the rhesus monkey is untenable. (4) The concept of Mesulam and Mufson (1985), that the primate insula is essentially composed of three concentrically arranged zones, agranular, dysgranular, and granular, is presumably correct, but there is at present much confusion concerning the more detailed architecture of the anterior insular cortex. (5) The large spindle-shaped cells in the fifth layer of the insular cortex, currently known as von Economo neurons (VENs), are not only confined to large-brained mammals, such as whales, elephants, apes, and humans, but also occur in monkeys and prosimians, as well as in the pygmy hippopotamus, the Atlantic walrus, and Florida manatee. Finally, we point out that the human insula presents a unique opportunity for performing an in-depth comparative analysis of the relations between structure and function in a typical sensory and a typical cognitive cortical domain. PMID:22230626

  9. Training transfers the limits on perception from parietal to ventral cortex.

    PubMed

    Chang, Dorita H F; Mevorach, Carmel; Kourtzi, Zoe; Welchman, Andrew E

    2014-10-20

    Visually guided behavior depends on (1) extracting and (2) discriminating signals from complex retinal inputs, and these perceptual skills improve with practice. For instance, training on aerial reconnaissance facilitated World War II Allied military operations; analysts pored over stereoscopic photographs, becoming expert at (1) segmenting pictures into meaningful items to break camouflage from (noisy) backgrounds, and (2) discriminating fine details to distinguish V-weapons from innocuous pylons. Training is understood to optimize neural circuits that process scene features (e.g., orientation) for particular purposes (e.g., judging position). Yet learning is most beneficial when it generalizes to other settings and is critical in recovery after adversity, challenging understanding of the circuitry involved. Here we used repetitive transcranial magnetic stimulation (rTMS) to infer the functional organization supporting learning generalization in the human brain. First, we show dissociable contributions of the posterior parietal cortex (PPC) versus lateral occipital (LO) circuits: extracting targets from noise is disrupted by PPC stimulation, in contrast to judging feature differences, which is affected by LO rTMS. Then, we demonstrate that training causes striking changes in this circuit: after feature training, identifying a target in noise is not disrupted by PPC stimulation but instead by LO stimulation. This indicates that training shifts the limits on perception from parietal to ventral brain regions and identifies a critical neural circuit for visual learning. We suggest that generalization is implemented by supplanting dynamic processing conducted in the PPC with specific feature templates stored in the ventral cortex. PMID:25283780

  10. Impaired synaptic plasticity in the visual cortex of mice lacking ?7-nicotinic receptor subunit.

    PubMed

    Criscuolo, C; Accorroni, A; Domenici, L; Origlia, N

    2015-05-21

    The primary visual cortex (V1) is the first step in visual information processing and its function may be modulated by acetylcholine through nicotinic receptors (nAChRs). Since our previous work demonstrated that visual acuity and cortical spatial resolution limit were significantly reduced in ?7 knock-out (KO) mice in the absence of retinal alterations, we decided to characterize the contribution of homomeric ?7 nicotinic receptors (?7nAChRs) to visual information processing at the cortical level. We evaluated long-term forms of synaptic plasticity in occipital slices containing V1 from ?7 KO mice and in wild-type (WT) slices perfused with nAChRs selective blocking agents. In ?7 KO mice slices, electrophysiological recordings demonstrated the absence of long-term potentiation (LTP) and long-term depression (LTD) in layer II/III after the stimulation of different intracortical pathways (layer IV or II/III). Furthermore, the acute and selective blockade of ?7nAChRs in slices from WT mice with either ?-bungarotoxin or methyllycaconitine did not alter the expression of LTP and LTD. Conversely, the perfusion with the unspecific nAChRs antagonist mecamylamine impaired LTP and LTD. Our results suggest the presence of impaired synaptic plasticity in the V1 of ?7 KO mice and indicate a different contribution of nAChRs to visual cortex function. PMID:25797465

  11. Right hemispheric dominance of visual phenomena evoked by intracerebral stimulation of the human visual cortex.

    PubMed

    Jonas, Jacques; Frismand, Solène; Vignal, Jean-Pierre; Colnat-Coulbois, Sophie; Koessler, Laurent; Vespignani, Hervé; Rossion, Bruno; Maillard, Louis

    2014-07-01

    Electrical brain stimulation can provide important information about the functional organization of the human visual cortex. Here, we report the visual phenomena evoked by a large number (562) of intracerebral electrical stimulations performed at low-intensity with depth electrodes implanted in the occipito-parieto-temporal cortex of 22 epileptic patients. Focal electrical stimulation evoked primarily visual hallucinations with various complexities: simple (spot or blob), intermediary (geometric forms), or complex meaningful shapes (faces); visual illusions and impairments of visual recognition were more rarely observed. With the exception of the most posterior cortical sites, the probability of evoking a visual phenomenon was significantly higher in the right than the left hemisphere. Intermediary and complex hallucinations, illusions, and visual recognition impairments were almost exclusively evoked by stimulation in the right hemisphere. The probability of evoking a visual phenomenon decreased substantially from the occipital pole to the most anterior sites of the temporal lobe, and this decrease was more pronounced in the left hemisphere. The greater sensitivity of the right occipito-parieto-temporal regions to intracerebral electrical stimulation to evoke visual phenomena supports a predominant role of right hemispheric visual areas from perception to recognition of visual forms, regardless of visuospatial and attentional factors. PMID:24733699

  12. Reduced Activity of Protein Kinase C in the Frontal Cortex of Subjects with Regressive Autism: Relationship with Developmental Abnormalities

    PubMed Central

    Ji, Lina; Chauhan, Abha; Chauhan, Ved

    2012-01-01

    Autism is a neurodevelopmental disorder with unknown etiology. In some cases, typically developing children regress into clinical symptoms of autism, a condition known as regressive autism. Protein kinases are essential for G-protein-coupled receptor-mediated signal transduction, and are involved in neuronal functions, gene expression, memory, and cell differentiation. Recently, we reported decreased activity of protein kinase A (PKA) in the frontal cortex of subjects with regressive autism. In the present study, we analyzed the activity of protein kinase C (PKC) in the cerebellum and different regions of cerebral cortex from subjects with regressive autism, autistic subjects without clinical history of regression, and age-matched control subjects. In the frontal cortex of subjects with regressive autism, PKC activity was significantly decreased by 57.1% as compared to age-matched control subjects (p = 0.0085), and by 65.8% as compared to non-regressed autistic subjects (p = 0.0048). PKC activity was unaffected in the temporal, parietal and occipital cortices, and in the cerebellum in both autism groups, i.e., regressive and non-regressed autism as compared to control subjects. These results suggest brain region-specific alteration of PKC activity in the frontal cortex of subjects with regressive autism. Further studies showed a negative correlation between PKC activity and restrictive, repetitive and stereotyped pattern of behavior (r= -0.084, p = 0.0363) in autistic individuals, suggesting involvement of PKC in behavioral abnormalities in autism. These findings suggest that regression in autism may be attributed, in part, to alterations in G-protein-coupled receptor-mediated signal transduction involving PKA and PKC in the frontal cortex. PMID:22949890

  13. Anatomy of the inferior petro-occipital vein and its relation to the base of the skull: application to surgical and endovascular procedures of the skull base.

    PubMed

    Tubbs, R Shane; Watanabe, Koichi; Loukas, Marios; Cohen-Gadol, Aaron A

    2014-07-01

    Although the inferior petro-occipital vein has been recently used for vascular access to the cavernous sinus, few detailed descriptions of its anatomy are in the literature. We aimed to investigate the morphology and relationships of this vessel. Twelve latex-injected cadaveric heads (24 sides) were dissected to identify the inferior petro-occipital vein and anatomic details documented. The petro-occipital vein was identified on 83.3% of sides. Generally this vein united the internal carotid venous plexus to the superior jugular bulb. However, on 10% of sides, the anterior part of this vein communicated directly with the cavernous sinus, and on 15%, the posterior vein drained into the inferior petrosal sinus at its termination into the superior jugular bulb. The petro-occipital vein was separated from the overlying inferior petrosal sinus by a thin plate of bone. On 40% of sides, small venous connections were found between these two venous structures. The vein was usually larger if a nondominant transverse sinus was present. The overlying inferior petrosal sinus was smaller in diameter when an underlying inferior petro-occipital vein was present. On 20% of sides, the posterior aspect of the vein communicated with the hypoglossal canal veins. On three sides, diploic veins from the clivus drained into the inferior petro-occipital vein. The inferior petro-occipital vein is present in most humans. This primarily extracranial vessel communicates with intracranial venous sinuses and should be considered an emissary vein. Knowledge of this vessel's exact anatomy may be useful to cranial base surgeons and endovascular specialists. PMID:23716071

  14. Attention modulates spatial priority maps in the human occipital, parietal and frontal cortices

    PubMed Central

    Sprague, Thomas C.; Serences, John T.

    2014-01-01

    Computational theories propose that attention modulates the topographical landscape of spatial ‘priority’ maps in regions of visual cortex so that the location of an important object is associated with higher activation levels. While single-unit recording studies have demonstrated attention-related increases in the gain of neural responses and changes in the size of spatial receptive fields, the net effect of these modulations on the topography of region-level priority maps has not been investigated. Here, we used fMRI and a multivariate encoding model to reconstruct spatial representations of attended and ignored stimuli using activation patterns across entire visual areas. These reconstructed spatial representations reveal the influence of attention on the amplitude and size of stimulus representations within putative priority maps across the visual hierarchy. Our results suggest that attention increases the amplitude of stimulus representations in these spatial maps, particularly in higher visual areas, but does not substantively change their size. PMID:24212672

  15. Late Complication of Surgically Treated Atlantoaxial Instability: Occipital Bone Erosion Induced by Protruded Fixed Titanium Rod: A Case Report

    PubMed Central

    Nakao, Yaoki; Shimokawa, Nobuyuki; Morisako, Hiroki; Tsukazaki, Yuji; Terada, Aiko; Nakajo, Kosuke; Fu, Yoshihiko

    2014-01-01

    Objective Polyaxial screw-rod fixation of C1-C2 is a relatively new technique to treat atlantoaxial instability, and there have been few reports in the literature outlining all possible complications. The purpose of this case report is to present the occurrence and management of occipital bone erosion induced by the protruded rostral part of a posterior atlantoaxial screw-rod construct causing headache. Clinical Features A 70-year-old Asian man with rheumatoid arthritis initially presented to our institution with atlantoaxial instability causing progressive quadraparesis and neck pain. Intervention and Outcome Posterior atlantoaxial instrumented fixation using C1 lateral mass screws in conjunction with C2 pedicle screws was performed to stabilize these segments. Postoperatively, the patient regained the ability to independently walk and had no radiographic evidence of instrumentation hardware failure and excellent sagittal alignment. However, despite a well-stabilized fusion, the patient began to complain of headache during neck extension. Follow-up imaging studies revealed left occipital bone erosion induced by a protruded titanium rod fixed with setscrews. During revision surgery, the rod protrusion was modified and the headaches diminished. Conclusion This case demonstrates that occipital bone erosion after posterior atlantoaxial fixation causing headache may occur. The principal cause of bone erosion in this case was rod protrusion. Although posterior atlantoaxial fixation using the screw-rod system was selected to manage atlantoaxial instability because it has less complications than other procedures, surgeons should pay attention that the length of the rod protrusion should not exceed 2 mm. PMID:25435842

  16. Mutations in extracellular matrix genes NID1 and LAMC1 cause autosomal dominant Dandy-Walker malformation and occipital cephaloceles

    PubMed Central

    Darbro, Benjamin W.; Mahajan, Vinit B.; Gakhar, Lokesh; Skeie, Jessica M.; Campbell, Elizabeth; Wu, Shu; Bing, Xinyu; Millen, Kathleen J.; Dobyns, William B.; Kessler, John A.; Jalali, Ali; Cremer, James; Segre, Alberto; Manak, J. Robert; Aldinger, Kimerbly A.; Suzuki, Satoshi; Natsume, Nagato; Ono, Maya; Hai, Huynh Dai; Viet, Le Thi; Loddo, Sara; Valente, Enza M.; Bernardini, Laura; Ghonge, Nitin; Ferguson, Polly J.; Bassuk, Alexander G.

    2013-01-01

    We performed whole-exome sequencing of a family with autosomal dominant Dandy-Walker malformation and occipital cephaloceles (ADDWOC) and detected a mutation in the extracellular matrix protein encoding gene NID1. In a second family, protein interaction network analysis identified a mutation in LAMC1, which encodes a NID1 binding partner. Structural modeling the NID1-LAMC1 complex demonstrated that each mutation disrupts the interaction. These findings implicate the extracellular matrix in the pathogenesis of Dandy-Walker spectrum disorders. PMID:23674478

  17. Acquired Chiari malformation secondary to atlantoaxial vertical subluxation in a patient with rheumatoid arthritis combined with atlanto-occipital assimilation.

    PubMed

    Kimura, Yuiko; Seichi, Atsushi; Gomi, Akira; Kojima, Masahiro; Inoue, Hirokazu; Kimura, Atsushi

    2012-01-01

    A 65-year-old woman with a history of rheumatoid arthritis presented with a rare case of acquired Chiari malformation secondary to atlantoaxial vertical subluxation, associated with congenital atlanto-occipital assimilation. Syringomyelia and tetraparesis improved immediately after posterior fossa decompression and simultaneous occipito-cervical junction fusion. The progression of acquired Chiari malformation is not well known. We concluded that coexisting assimilation accelerated crowded foramen magnum following atlantoaxial vertical subluxation and induced acquired Chiari malformation over the course of a few years. PMID:23006887

  18. Occipital condyle fractures. Prospective follow-up of 31 cases within 5 years at a level 1 trauma centre

    Microsoft Academic Search

    Franz Josef Mueller; Bernd Fuechtmeier; Bernd Kinner; Michael Rosskopf; Carsten Neumann; Michael Nerlich; Carsten Englert

    Purpose  Prospective investigation of incidence and outcome of occipital condyle fractures (OCF) in a level 1 trauma centre.\\u000a \\u000a \\u000a \\u000a Methods  Over a period of 5 years, we prospectively recorded all cases of OCF, and performed a 1-year post-injury radiological and\\u000a clinical follow-up using CT imaging, SF-36 and Neck Disability Index, respectively.\\u000a \\u000a \\u000a \\u000a \\u000a Results  A total of 31 patients with OCF were identified. Based on a total

  19. Sensory-specific anomic aphasia following left occipital lesions: Data from free oral descriptions of concrete word meanings

    PubMed Central

    Mårtensson, F.; Roll, M.; Lindgren, M.; Apt, P.; Horne, M.

    2013-01-01

    The present study investigated hierarchical lexical semantic structure in oral descriptions of concrete word meanings produced by a subject (ZZ) diagnosed with anomic aphasia due to left occipital lesions. The focus of the analysis was production of a) nouns at different levels of semantic specificity (e.g., “robin”–“bird”–“animal”) and b) words describing sensory or motor experiences (e.g., “blue,” “soft,” “fly”). Results show that in contrast to healthy and aphasic controls, who produced words at all levels of specificity and mainly vision-related sensory information, ZZ produced almost exclusively nouns at the most non-specific levels and words associated with sound and movement. PMID:23425233

  20. Sensory-specific anomic aphasia following left occipital lesions: data from free oral descriptions of concrete word meanings.

    PubMed

    Mårtensson, F; Roll, M; Lindgren, M; Apt, P; Horne, M

    2014-04-01

    The present study investigated hierarchical lexical semantic structure in oral descriptions of concrete word meanings produced by a subject (ZZ) diagnosed with anomic aphasia due to left occipital lesions. The focus of the analysis was production of a) nouns at different levels of semantic specificity (e.g., "robin"-"bird"-"animal") and b) words describing sensory or motor experiences (e.g., "blue," "soft," "fly"). Results show that in contrast to healthy and aphasic controls, who produced words at all levels of specificity and mainly vision-related sensory information, ZZ produced almost exclusively nouns at the most non-specific levels and words associated with sound and movement. PMID:23425233

  1. Joint effects of polymorphisms in the HTRA1, LOC387715\\/ ARMS2, and CFH genes on AMD in a Caucasian population

    Microsoft Academic Search

    Peter J Francis; Hong Zhang; Andrew DeWan; Josephine Hoh; Michael L Klein

    2008-01-01

    Purpose: To estimate the joint effects of single nucleotide polymorphysms (SNPs) in the genes complement factor H (CFH), HtrA serine peptidase 1 (HTRA1), and age-related maculopathy susceptibility 2 (LOC387715\\/ARMS2) in a Caucasian age related macular degeneration (AMD) case-control cohort. Methods: We genotyped three SNPs, rs1061170 (exon 9, CFH), rs11200638 (HTRA1 promoter, ?512 bp), and rs10490924 (6.6 kb upstream of HTRA1

  2. Sequence variants in HTRA1 and LOC387715\\/ARMS2 and phenotype and response to photodynamic therapy in neovascular age-related macular degeneration in populations from Israel

    Microsoft Academic Search

    Itay Chowers; Tal Meir; Michal Lederman; Nitza Goldenberg-Cohen; Yoram Cohen; Eyal Banin; Edward Averbukh; Itzhak Hemo; Ayala Pollack; Ruth Axer-Siegel; Orly Weinstein; Josephine Hoh; Donald J. Zack; Tural Galbinur

    2008-01-01

    Purpose: Single nucleotide polymorphisms (SNPs) in the tightly linked LOC387715\\/ARMS2 and HTRA1 genes have been associated with age-related macular degeneration (AMD). We tested whether these SNPs are associated with AMD in Israeli populations, if they underlie variable phenotype and response to therapy in neovascular AMD (NVAMD), and if HTRA1 expression in vivo is associated with its promoter variant. Methods: Genotyping

  3. The multifunctional application of microfluidic lab-on-a-chip surface enhanced Raman spectroscopy (LOC-SERS) within the field of bioanalytics

    Microsoft Academic Search

    Anne März; Bettina Mönch; Angela Walter; Thomas Bocklitz; Wilm Schumacher; Petra Rösch; Michael Kiehntopf; Jürgen Popp

    2011-01-01

    This contribution will present a variety of applications of lab-on-a-chip surface enhanced Raman spectroscopy in the field of bioanalytic. Beside the quantification and online monitoring of drugs and pharmaceuticals, determination of enzyme activity and discrimination of bacteria are successfully carried out utilizing LOC-SERS. The online-monitoring of drugs using SERS in a microfluidic device is demonstrated for nicotine. The enzyme activity

  4. ALCOHOL AND THE PREFRONTAL CORTEX

    PubMed Central

    Abernathy, Kenneth; Chandler, L. Judson; Woodward, John J.

    2013-01-01

    The prefrontal cortex occupies the anterior portion of the frontal lobes and is thought to be one of the most complex anatomical and functional structures of the mammalian brain. Its major role is to integrate and interpret inputs from cortical and sub-cortical structures and use this information to develop purposeful responses that reflect both present and future circumstances. This includes both action-oriented sequences involved in obtaining rewards and inhibition of behaviors that pose undue risk or harm to the individual. Given the central role in initiating and regulating these often complex cognitive and behavioral responses, it is no surprise that alcohol has profound effects on the function of the prefrontal cortex. In this chapter, we review the basic anatomy and physiology of the prefrontal cortex and discuss what is known about the actions of alcohol on the function of this brain region. This includes a review of both the human and animal literature including information on the electrophysiological and behavioral effects that follow acute and chronic exposure to alcohol. The chapter concludes with a discussion of unanswered questions and areas needing further investigation. PMID:20813246

  5. An analysis of von Economo neurons in the cerebral cortex of cetaceans, artiodactyls, and perissodactyls.

    PubMed

    Raghanti, Mary Ann; Spurlock, Linda B; Robert Treichler, F; Weigel, Sara E; Stimmelmayr, Raphaela; Butti, Camilla; Hans Thewissen, J G M; Hof, Patrick R

    2015-07-01

    Von Economo neurons (VENs) are specialized projection neurons with a characteristic spindle-shaped soma and thick basal and apical dendrites. VENs have been described in restricted cortical regions, with their most frequent appearance in layers III and V of the anterior cingulate cortex, anterior insula, and frontopolar cortex of humans, great apes, macaque monkeys, elephants, and some cetaceans. Recently, a ubiquitous distribution of VENs was reported in various cortical areas in the pygmy hippopotamus, one of the closest living relatives of cetaceans. That finding suggested that VENs might not be unique to only a few species that possess enlarged brains. In the present analysis, we assessed the phylogenetic distribution of VENs within species representative of the superordinal clade that includes cetartiodactyls and perissodactyls, as well as afrotherians. In addition, the distribution of fork cells that are often found in close proximity to VENs was also assessed. Nissl-stained sections from the frontal pole, anterior cingulate cortex, anterior insula, and occipital pole of bowhead whale, cow, sheep, deer, horse, pig, rock hyrax, and human were examined using stereologic methods to quantify VENs and fork cells within layer V of all four cortical regions. VENs and fork cells were found in each of the species examined here with species-specific differences in distributions and densities. The present results demonstrated that VENs and fork cells were not restricted to highly encephalized or socially complex species, and their repeated emergence among distantly related species seems to represent convergent evolution of specialized pyramidal neurons. The widespread phylogenetic presence of VENs and fork cells indicates that these neuron morphologies readily emerged in response to selective forces,whose variety and nature are yet to be identified. PMID:24852852

  6. Investigating Representations of Facial Identity in Human Ventral Visual Cortex with Transcranial Magnetic Stimulation

    PubMed Central

    Gilaie-Dotan, Sharon; Silvanto, Juha; Schwarzkopf, Dietrich S.; Rees, Geraint

    2010-01-01

    The occipital face area (OFA) is face-selective. This enhanced activation to faces could reflect either generic face and shape-related processing or high-level conceptual processing of identity. Here we examined these two possibilities using a state-dependent transcranial magnetic stimulation (TMS) paradigm. The lateral occipital (LO) cortex which is activated non-selectively by various types of objects served as a control site. We localized OFA and LO on a per-participant basis using functional MRI. We then examined whether TMS applied to either of these regions affected the ability of participants to decide whether two successively presented and physically different face images were of the same famous person or different famous people. TMS was applied during the delay between first and second face presentations to investigate whether neuronal populations in these regions played a causal role in mediating the behavioral effects of identity repetition. Behaviorally we found a robust identity repetition effect, with shorter reaction times (RTs) when identity was repeated, regardless of the fact that the pictures were physically different. Surprisingly, TMS applied over LO (but not OFA) modulated overall RTs, compared to the No-TMS condition. But critically, we found no effects of TMS to either area that were modulated by identity repetition. Thus, we found no evidence to suggest that OFA or LO contain neuronal representations selective for the identity of famous faces which play a causal role in identity processing. Instead, these brain regions may be involved in the processing of more generic features of their preferred stimulus categories. PMID:20631842

  7. Topographic organization of projections from the amygdala to the visual cortex in the macaque monkey.

    PubMed

    Amaral, D G; Behniea, H; Kelly, J L

    2003-01-01

    The topography of amygdaloid projections to the visual cortices in the macaque monkey was examined by injecting the fluorescent tracers Fast Blue and Diamidino Yellow at different locations in the occipital and temporal lobes and mapping the distribution of retrogradely labeled cells in the amygdala. Injections involving regions from rostral area TE to caudal area V1 all resulted in labeled cells within the basal nucleus of the amygdala. Relatively few double-labeled cells were observed even when the two injections were separated by less than 3 mm. The projections were rostrocaudally organized such that projections to caudal visual areas originated from dorsal and caudal portions of the magnocellular division of the basal nucleus while projections to more rostrally situated visual areas originated in more rostral and ventral portions of the basal nucleus. When injections involved rostral and medial portions of area TE, retrogradely labeled cells were observed in the accessory basal and lateral nuclei in addition to the basal nucleus. These data confirm that the amygdala gives rise to feedback projections to all levels of the "ventral stream" visual pathway. The projections do not appear to be diffusely distributed since few double-labeled cells were observed. The largest cells of the basal nucleus, those located in the magnocellular division, project the farthest in the visual system and innervate all occipital and temporal levels. The smaller cells, in the intermediate and parvicellular regions, project to more rostral and medial portions of the visual cortex. These results suggest that the amygdala may have substantial modulatory control over sensory processing at all stages of the ventral-stream visual cortical hierarchy. PMID:12732254

  8. Rapid, high-frequency, and theta-coupled gamma oscillations in the inferior occipital gyrus during face processing.

    PubMed

    Sato, Wataru; Kochiyama, Takanori; Uono, Shota; Matsuda, Kazumi; Usui, Keiko; Inoue, Yushi; Toichi, Motomi

    2014-11-01

    Neuroimaging studies have found greater activation in the inferior occipital gyrus (IOG), or occipital face area, in response to faces relative to non-facial stimuli. However, the temporal, frequency, and functional profiles of IOG activity during face processing remain unclear. Here, this issue was investigated by recording intracranial field potentials in the IOG during the presentation of faces, mosaics, and houses in upright and inverted orientations. Time-frequency statistical parametric mapping analyses revealed greater gamma-band activation in the IOG beginning at 110 msec and covering 40-300 Hz in response to upright faces relative to upright houses and mosaics. Phase-amplitude cross-frequency coupling analyses revealed more evident theta-gamma couplings at 115-256 msec during the processing of upright faces as compared with that of upright houses and mosaics. Comparable gamma-band activity was observed during the processing of inverted and upright faces at about 100-200 msec, but weaker activity and different coupling with theta-band activity after 200 msec. These patterns of activity were more evident in the right than in the left IOG. These results, together with other evidence on neural communication, suggest that broadband gamma oscillations in the right IOG conduct rapid and multistage (i.e., both featural and configural) face processing in collaboration with theta oscillations transmitted from other brain regions. PMID:24745564

  9. Decreased white matter integrity in fronto-occipital fasciculus bundles: relation to visual information processing in alcohol-dependent subjects.

    PubMed

    Bagga, Deepika; Sharma, Aakansha; Kumari, Archana; Kaur, Prabhjot; Bhattacharya, Debajyoti; Garg, Mohan Lal; Khushu, Subash; Singh, Namita

    2014-02-01

    Chronic alcohol abuse is characterized by impaired cognitive abilities with a more severe deficit in visual than in verbal functions. Neuropathologically, it is associated with widespread brain structural compromise marked by gray matter shrinkage, ventricular enlargement, and white matter degradation. The present study sought to increase current understanding of the impairment of visual processing abilities in alcohol-dependent subjects, and its correlation with white matter microstructural alterations, using diffusion tensor imaging (DTI). To that end, a DTI study was carried out on 35 alcohol-dependent subjects and 30 healthy male control subjects. Neuropsychological tests were assessed for visual processing skills and deficits were reported as raw dysfunction scores (rDyS). Reduced FA (fractional anisotropy) and increased MD (mean diffusivity) were observed bilaterally in inferior and superior fronto-occipital fasciculus (FOF) fiber bundles. A significant inverse correlation in rDyS and FA values was observed in these fiber tracts whereas a positive correlation of these scores was found with the MD values. Our results suggest that FOF fiber bundles linking the frontal lobe to occipital lobe might be related to visual processing skills. This is the first report of an alteration of the white matter microstructure of FOF fiber bundles that might have functional consequences for visual processing in alcohol-dependent subjects who exhibit no neurological complications. PMID:24388377

  10. ?-Aminobutyric acid (GABA) concentration inversely correlates with basal perfusion in human occipital lobe

    PubMed Central

    Donahue, Manus J; Rane, Swati; Hussey, Erin; Mason, Emily; Pradhan, Subechhya; Waddell, Kevin W; Ally, Brandon A

    2014-01-01

    Commonly used neuroimaging approaches in humans exploit hemodynamic or metabolic indicators of brain function. However, fundamental gaps remain in our ability to relate such hemo-metabolic reactivity to neurotransmission, with recent reports providing paradoxical information regarding the relationship among basal perfusion, functional imaging contrast, and neurotransmission in awake humans. Here, sequential magnetic resonance spectroscopy (MRS) measurements of the primary inhibitory neurotransmitter, ?-aminobutyric acid (GABA+macromolecules normalized by the complex N-acetyl aspartate-N-acetyl aspartyl glutamic acid: [GABA+]/[NAA–NAAG]), and magnetic resonance imaging (MRI) measurements of perfusion, fractional gray-matter volume, and arterial arrival time (AAT) are recorded in human visual cortex from a controlled cohort of young adult male volunteers with neurocognitive battery-confirmed comparable cognitive capacity (3?T; n=16; age=23±3 years). Regression analyses reveal an inverse correlation between [GABA+]/[NAA–NAAG] and perfusion (R=?0.46; P=0.037), yet no relationship between AAT and [GABA+]/[NAA–NAAG] (R=?0.12; P=0.33). Perfusion measurements that do not control for AAT variations reveal reduced correlations between [GABA+]/[NAA–NAAG] and perfusion (R=?0.13; P=0.32). These findings largely reconcile contradictory reports between perfusion and inhibitory tone, and underscore the physiologic origins of the growing literature relating functional imaging signals, hemodynamics, and neurotransmission. PMID:24398941

  11. Rescaling retinal size into perceived size: evidence for an occipital and parietal bottleneck.

    PubMed

    Kreutzer, Sylvia; Weidner, Ralph; Fink, Gereon R

    2015-07-01

    The spatial and temporal context of an object influence its perceived size. Two visual illusions illustrate this nicely: the size adaptation effect and the Ebbinghaus illusion. Whereas size adaptation affects size rescaling of a target circle via a previously presented, differently sized adaptor circle, the Ebbinghaus illusion alters perceived size by virtue of surrounding circles. In the classical Ebbinghaus setting, the surrounding circles are shown simultaneously with the target. However, size underestimation persists when the surrounding circles precede the target. Such a temporal separation of inducer and target circles in both illusions permits the comparison of BOLD signals elicited by two displays that, although objectively identical, elicit different percepts. The current study combined both illusions in a factorial design to identify a presumed common central mechanism involved in rescaling retinal into perceived size. At the behavioral level, combining both illusions did not affect perceived size further. At the neural level, however, this combination induced functional activation beyond that induced by either illusion separately: An underadditive activation pattern was found within left lingual gyrus, right supramarginal gyrus, and right superior parietal cortex. These findings provide direct behavioral and functional evidence for the presence of a neural bottleneck in rescaling retinal into perceived size, a process vital for visual perception. PMID:25603028

  12. Mapping Prefrontal Cortex Functions in Human Infancy

    ERIC Educational Resources Information Center

    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…

  13. The visual cortex as a crystal

    Microsoft Academic Search

    Paul C. Bressloff; Jack D. Cowan

    2002-01-01

    A theory of pattern formation in primary visual cortex (V1) is presented that takes into account its crystalline-like structure. The cortex is partitioned into fundamental domains or hypercolumnsof a lattice describing the distribution of singularities or pinwheels in the orientation preference map. Each hypercolumn is modelled as a network of orientation and spatial frequency selective cells organised around a pair

  14. Multi-voxel pattern analysis of selective representation of visual working memory in ventral temporal and occipital regions.

    PubMed

    Han, Xufeng; Berg, Alexander C; Oh, Hwamee; Samaras, Dimitris; Leung, Hoi-Chung

    2013-06-01

    While previous results from univariate analysis showed that the activity level of the parahippocampal gyrus (PHG) but not the fusiform gyrus (FG) reflects selective maintenance of the cued picture category, present results from multi-voxel pattern analysis (MVPA) showed that the spatial response patterns of both regions can be used to differentiate the selected picture category in working memory. The ventral temporal and occipital areas including the PHG and FG have been shown to be specialized in perceiving and processing different kinds of visual information, though their role in the representation of visual working memory remains unclear. To test whether the PHG and FG show spatial response patterns that reflect selective maintenance of task-relevant visual working memory in comparison with other posterior association regions, we reanalyzed data from a previous fMRI study of visual working memory with a cue inserted during the delay period of a delayed recognition task. Classification of FG and PHG activation patterns for the selected category (face or scene) during the cue phase was well above chance using classifiers trained with fMRI data from the cue or probe phase. Classification of activity in other temporal and occipital regions for the cued picture category during the cue phase was relatively less consistent even though classification of their activity during the probe recognition was comparable with the FG and PHG. In sum, these findings suggest that the FG and PHG carry information relevant to the cued visual category, and their spatial activation patterns during selective maintenance seem to match those during visual recognition. PMID:23380167

  15. R3P-Loc: a compact multi-label predictor using ridge regression and random projection for protein subcellular localization.

    PubMed

    Wan, Shibiao; Mak, Man-Wai; Kung, Sun-Yuan

    2014-11-01

    Locating proteins within cellular contexts is of paramount significance in elucidating their biological functions. Computational methods based on knowledge databases (such as gene ontology annotation (GOA) database) are known to be more efficient than sequence-based methods. However, the predominant scenarios of knowledge-based methods are that (1) knowledge databases typically have enormous size and are growing exponentially, (2) knowledge databases contain redundant information, and (3) the number of extracted features from knowledge databases is much larger than the number of data samples with ground-truth labels. These properties render the extracted features liable to redundant or irrelevant information, causing the prediction systems suffer from overfitting. To address these problems, this paper proposes an efficient multi-label predictor, namely R3P-Loc, which uses two compact databases for feature extraction and applies random projection (RP) to reduce the feature dimensions of an ensemble ridge regression (RR) classifier. Two new compact databases are created from Swiss-Prot and GOA databases. These databases possess almost the same amount of information as their full-size counterparts but with much smaller size. Experimental results on two recent datasets (eukaryote and plant) suggest that R3P-Loc can reduce the dimensions by seven-folds and significantly outperforms state-of-the-art predictors. This paper also demonstrates that the compact databases reduce the memory consumption by 39 times without causing degradation in prediction accuracy. For readers? convenience, the R3P-Loc server is available online at url:http://bioinfo.eie.polyu.edu.hk/R3PLocServer/. PMID:24997236

  16. Feasibility of Use of a Barbed Suture (V-Loc 180) for Quilting the Donor Site in Latissimus Dorsi Myocutaneous Flap Breast Reconstruction

    PubMed Central

    Hussain, Tasadooq; Mahapatra, Tapan Kumar; McManus, Penelope Louise; Kneeshaw, Peter John

    2013-01-01

    Background Latissimus dorsi (LD) myocutaneous flap is a popular method of breast reconstruction which can be associated with high incidence of seroma formation. Quilting sutures at the harvest site are used to reduce this. Barbed sutures are self anchoring sutures which avoid multiple knotting and can be useful in quilting. Methods A retrospective analysis of prospectively maintained database of patients who underwent LD flap breast reconstruction between January 2009 and January 2011 was carried out. Seroma formation at the harvest site, wound related complications, inpatient stay and duration of surgery were analysed and a comparison was made between two groups where quilting was done with barbed (V-Loc) suture and conventional polydioxanone (PDS) II sutures. Results Fifty-seven patients were included of which 33 had quilting by V-Loc sutures and in 24 patients PDS II suture was used. Median age in the PDS group was 55 years (interquartile range [IQR)], 45 to 61 years) which was comparable to the V-Loc group (53 years [IQR, 48 to 59 years]; P-value 0.948). Sixteen patients (28%) had significant seroma formation and 5 (9%) patients developed superficial wound dehiscence. Incidences of seroma or wound complications were comparable (P-value 0.378 and 1.00, respectively). Secondary outcomes such as total duration of surgery, total inpatient stay, total amount of drain at the donor site were also similar in two groups. Conclusions Use of barbed sutures for quilting the donor site in LD flap reconstruction is a feasible option and the associated seroma formation and wound complications are comparable with conventional sutures. PMID:23532830

  17. Progressive Cognitive Impairment Evolving to Dementia Parallels Parieto-Occipital and Temporal Enlargement in Idiopathic Chronic Hydrocephalus: A Retrospective Cohort Study

    PubMed Central

    Missori, Paolo; Currà, Antonio

    2015-01-01

    Little is known regarding progressive enlargement of the ventricular system in symptomatic patients or asymptomatic subjects. Before eventual surgical treatment, we evaluated the clinical and radiological features of an extremely rare group of patients with idiopathic chronic hydrocephalus (ICH) and cognitive impairment evolving to dementia (n?=?11), and an extremely rare group of asymptomatic or minimally symptomatic adults (AMSA) with ventricular enlargement (n?=?10). We quantified changes over time in the ventricular frontal, occipital, and temporal horns by measuring the Evans’ index plus a parieto-occipital ratio and a temporal ratio, and their percentage of progression. Cerebral ventricles expanded over very long term in both demented patients with ICH and in AMSA. In AMSA, frontal enlargement predominated, whereas demented patients showed predominant parieto-occipital (p?=?0.00) and temporal (p?=?0.00) enlargement that progressed faster than in AMSA (p?=?0.00). In ICH, progression of cognitive impairment parallels ventricular parieto-occipital and temporal horn enlargement. Limitations of this study are the retrospective nature, the non-uniform use of neuropsychological tests, the reduced sample size due to the extremely stringent enrollment criteria, the inability to determine the precise rate of progression. PMID:25759681

  18. Efficacy of sodium valproate in the treatment of photosensitive epilepsy (PSE) and the probable reasons for the persistence of occipital spikes.

    PubMed

    Anyanwu, Ebere C; Ehiri, John E; Campbell, Andrew W

    2004-07-15

    Intermittent photic stimulation (IPS) in patients with photosensitive epilepsy (PSE) leads to EEG abnormalities, which include generalized discharges with spike and wave activity. This paper investigates 33 PSE patients, 14 (42%) males and 19 (58%) females. The age range was between 8 and 45 years. After the treatment of the patients with sodium valproate (VPA), the EEG examinations showed that the generalized discharges disappeared, while the occipital spikes persisted. The mechanism of action of VPA was re-evaluated in order to ascertain whether or not the persistent occipital was due to a failure in inhibitory postsynaptic potential (IPSP). It was concluded that the possible causes of VPA's inefficacy in abolishing occipital spikes in PSE was not necessarily due to a failure in IPSP, but rather it could be due to a time-dependent failure of certain cells of the visual system to respond positively to the VPA's modulatory activity, probably involving the ionic channels, neurotransmitters, and the second messenger systems. The relationship between occipital spikes and visual evoked response is discussed. The extent to which metabolic processes and neurotransmitters are involved is also evaluated. PMID:15311327

  19. Supplement to Vol. 19, 2000 ACTA ANTHROPOLOGICA SINICA 37-46 Thickness Mapping of the Occipital Bone on CT-data

    E-print Network

    Neumaier, Arnold

    , University of Vienna, Strudlhofgasse 4, A-1090 Vienna, AUSTRIA; 3. Dept. of Anatomy & Histology, Muhimbili of thickness combined with aspects of functional anatomy. Key words: Occipital bone; Bone thickness; Hominid evolution; Virtual anthropology; Computed tomography 1 Introduction Information about the thickness

  20. Merosin-negative congenital muscular dystrophy, occipital epilepsy with periodic spasms and focal cortical dysplasia. Report of three Italian cases in two families

    Microsoft Academic Search

    Antonella Pini; Luciano Merlini; Fernando M. S. Tome´; Martine Chevallay; Giuseppe Gobbi

    1996-01-01

    We report clinical, EEG and neuroimaging findings of three patients in two Italian families with merosin-negative congenital muscular dystrophy (CMD), drug-resistant occipital epilepsy, diffuse persistent cerebral white matter changes and focal cortical dysplasia. Clinical and epilepsy histories, EEG and neuroimaging findings were very similar in all patients. Seizures started in childhood and mainly consisted of periodic spasms, a particular type

  1. Addiction and the adrenal cortex

    PubMed Central

    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

  2. Evaluative vs. trait representation in intergroup social judgments: distinct roles of anterior temporal lobe and prefrontal cortex.

    PubMed

    Gilbert, Sam J; Swencionis, Jillian K; Amodio, David M

    2012-12-01

    When interacting with someone from another social group, one's responses may be influenced by both stereotypes and evaluations. Given behavioral results suggesting that stereotypes and evaluative associations operate independently, we used fMRI to test whether these biases are mediated by distinct brain systems. White participants viewed pairs of Black or White faces and judged them based on an evaluation (who would you befriend?) or a stereotype-relevant trait (who is more likely to enjoy athletic activities?). Multi-voxel pattern analysis revealed that a predominantly occipital network represented race in a context-invariant manner. However, lateral orbitofrontal cortex preferentially represented race during friendship judgments, whereas anterior medial prefrontal cortex preferentially represented race during trait judgments. Furthermore, representation of race in left temporal pole correlated with a behavioral measure of evaluative bias during friendship judgments and, independently, a measure of stereotyping during trait judgments. Whereas early sensory regions represent race in an apparently invariant manner, representations in higher-level regions are multi-componential and context-dependent. PMID:22975194

  3. Vocalization Induced CFos Expression in Marmoset Cortex

    PubMed Central

    Miller, Cory T.; DiMauro, Audrey; Pistorio, Ashley; Hendry, Stewart; Wang, Xiaoqin

    2010-01-01

    All non-human primates communicate with conspecifics using vocalizations, a system involving both the production and perception of species-specific vocal signals. Much of the work on the neural basis of primate vocal communication in cortex has focused on the sensory processing of vocalizations, while relatively little data are available for vocal production. Earlier physiological studies in squirrel monkeys had shed doubts on the involvement of primate cortex in vocal behaviors. The aim of the present study was to identify areas of common marmoset (Callithrix jacchus) cortex that are potentially involved in vocal communication. In this study, we quantified cFos expression in three areas of marmoset cortex – frontal, temporal (auditory), and medial temporal – under various vocal conditions. Specifically, we examined cFos expression in these cortical areas during the sensory, motor (vocal production), and sensory–motor components of vocal communication. Our results showed an increase in cFos expression in ventrolateral prefrontal cortex as well as the medial and lateral belt areas of auditory cortex in the vocal perception condition. In contrast, subjects in the vocal production condition resulted in increased cFos expression only in dorsal premotor cortex. During the sensory–motor condition (antiphonal calling), subjects exhibited cFos expression in each of the above areas, as well as increased expression in perirhinal cortex. Overall, these results suggest that various cortical areas outside primary auditory cortex are involved in primate vocal communication. These findings pave the way for further physiological studies of the neural basis of primate vocal communication. PMID:21179582

  4. Altered Structural and Functional Connectivity in Late Preterm Preadolescence: An Anatomic Seed-Based Study of Resting State Networks Related to the Posteromedial and Lateral Parietal Cortex

    PubMed Central

    Degnan, Andrew J.; Wisnowski, Jessica L.; Choi, SoYoung; Ceschin, Rafael; Bhushan, Chitresh; Leahy, Richard M.; Corby, Patricia; Schmithorst, Vincent J.; Panigrahy, Ashok

    2015-01-01

    Objective Late preterm birth confers increased risk of developmental delay, academic difficulties and social deficits. The late third trimester may represent a critical period of development of neural networks including the default mode network (DMN), which is essential to normal cognition. Our objective is to identify functional and structural connectivity differences in the posteromedial cortex related to late preterm birth. Methods Thirty-eight preadolescents (ages 9–13; 19 born in the late preterm period (?32 weeks gestational age) and 19 at term) without access to advanced neonatal care were recruited from a low socioeconomic status community in Brazil. Participants underwent neurocognitive testing, 3-dimensional T1-weighted imaging, diffusion-weighted imaging and resting state functional MRI (RS-fMRI). Seed-based probabilistic diffusion tractography and RS-fMRI analyses were performed using unilateral seeds within the posterior DMN (posterior cingulate cortex, precuneus) and lateral parietal DMN (superior marginal and angular gyri). Results Late preterm children demonstrated increased functional connectivity within the posterior default mode networks and increased anti-correlation with the central-executive network when seeded from the posteromedial cortex (PMC). Key differences were demonstrated between PMC components with increased anti-correlation with the salience network seen only with posterior cingulate cortex seeding but not with precuneus seeding. Probabilistic tractography showed increased streamlines within the right inferior longitudinal fasciculus and inferior fronto-occipital fasciculus within late preterm children while decreased intrahemispheric streamlines were also observed. No significant differences in neurocognitive testing were demonstrated between groups. Conclusion Late preterm preadolescence is associated with altered functional connectivity from the PMC and lateral parietal cortex to known distributed functional cortical networks despite no significant executive neurocognitive differences. Selective increased structural connectivity was observed in the setting of decreased posterior interhemispheric connections. Future work is needed to determine if these findings represent a compensatory adaptation employing alternate neural circuitry or could reflect subtle pathology resulting in emotional processing deficits not seen with neurocognitive testing. PMID:26098888

  5. Training Transfers the Limits on Perception from Parietal to Ventral Cortex

    PubMed Central

    Chang, Dorita H.F.; Mevorach, Carmel; Kourtzi, Zoe; Welchman, Andrew E.

    2014-01-01

    Summary Visually guided behavior depends on (1) extracting and (2) discriminating signals from complex retinal inputs, and these perceptual skills improve with practice [1]. For instance, training on aerial reconnaissance facilitated World War II Allied military operations [2]; analysts pored over stereoscopic photographs, becoming expert at (1) segmenting pictures into meaningful items to break camouflage from (noisy) backgrounds, and (2) discriminating fine details to distinguish V-weapons from innocuous pylons. Training is understood to optimize neural circuits that process scene features (e.g., orientation) for particular purposes (e.g., judging position) [3–6]. Yet learning is most beneficial when it generalizes to other settings [7, 8] and is critical in recovery after adversity [9], challenging understanding of the circuitry involved. Here we used repetitive transcranial magnetic stimulation (rTMS) to infer the functional organization supporting learning generalization in the human brain. First, we show dissociable contributions of the posterior parietal cortex (PPC) versus lateral occipital (LO) circuits: extracting targets from noise is disrupted by PPC stimulation, in contrast to judging feature differences, which is affected by LO rTMS. Then, we demonstrate that training causes striking changes in this circuit: after feature training, identifying a target in noise is not disrupted by PPC stimulation but instead by LO stimulation. This indicates that training shifts the limits on perception from parietal to ventral brain regions and identifies a critical neural circuit for visual learning. We suggest that generalization is implemented by supplanting dynamic processing conducted in the PPC with specific feature templates stored in the ventral cortex. PMID:25283780

  6. The cerebral cortex of Albert Einstein: a description and preliminary analysis of unpublished photographs

    PubMed Central

    Lepore, Frederick E.; Noe, Adrianne

    2013-01-01

    Upon his death in 1955, Albert Einstein’s brain was removed, fixed and photographed from multiple angles. It was then sectioned into 240 blocks, and histological slides were prepared. At the time, a roadmap was drawn that illustrates the location within the brain of each block and its associated slides. Here we describe the external gross neuroanatomy of Einstein’s entire cerebral cortex from 14 recently discovered photographs, most of which were taken from unconventional angles. Two of the photographs reveal sulcal patterns of the medial surfaces of the hemispheres, and another shows the neuroanatomy of the right (exposed) insula. Most of Einstein’s sulci are identified, and sulcal patterns in various parts of the brain are compared with those of 85 human brains that have been described in the literature. To the extent currently possible, unusual features of Einstein’s brain are tentatively interpreted in light of what is known about the evolution of higher cognitive processes in humans. As an aid to future investigators, these (and other) features are correlated with blocks on the roadmap (and therefore histological slides). Einstein’s brain has an extraordinary prefrontal cortex, which may have contributed to the neurological substrates for some of his remarkable cognitive abilities. The primary somatosensory and motor cortices near the regions that typically represent face and tongue are greatly expanded in the left hemisphere. Einstein’s parietal lobes are also unusual and may have provided some of the neurological underpinnings for his visuospatial and mathematical skills, as others have hypothesized. Einstein’s brain has typical frontal and occipital shape asymmetries (petalias) and grossly asymmetrical inferior and superior parietal lobules. Contrary to the literature, Einstein’s brain is not spherical, does not lack parietal opercula and has non-confluent Sylvian and inferior postcentral sulci. PMID:23161163

  7. Locating the functional and anatomical boundaries of human primary visual cortex

    PubMed Central

    Hinds, Oliver; Polimeni, Jonathan R.; Rajendran, Niranjini; Balasubramanian, Mukund; Amunts, Katrin; Zilles, Karl; Schwartz, Eric L.; Fischl, Bruce; Triantafyllou, Christina

    2009-01-01

    The primary visual cortex (V1) can be delineated both functionally by its topographic map of the visual field and anatomically by its distinct pattern of laminar myelination. Although it is commonly assumed that the specialized anatomy V1 exhibits corresponds in location with functionally defined V1, demonstrating this in human has not been possible thus far due to the difficulty of determining the location of V1 both functionally and anatomically in the same individual. In this study we use MRI to measure the anatomical and functional V1 boundaries in the same individual and demonstrate close agreement between them. Functional V1 location was measured by parcellating occipital cortex of 10 living humans into visual cortical areas based on the topographic map of the visual field measured using functional MRI. Anatomical V1 location was estimated for these same subjects using a surface-based probabilistic atlas derived from high-resolution structural MRI of the stria of Gennari in 10 intact ex vivo human hemispheres. To ensure that the atlas prediction was correct, it was validated against V1 location measured using an observer-independent cortical parcellation based on the laminar pattern of cell density in serial brain sections from 10 separate individuals. The close agreement between the independent anatomically and functionally derived V1 boundaries indicates that the whole extent of V1 can be accurately predicted based on cortical surface reconstructions computed from structural MRI scans, eliminating the need for functional localizers of V1. In addition, that the primary cortical folds predict the location of functional V1 suggests that the mechanism giving rise to V1 location is tied to the development of the cortical folds. PMID:19328238

  8. The Role of Human Parietal Cortex in Attention Networks

    ERIC Educational Resources Information Center

    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…

  9. Chromosome 11: Ubiquilin 3 and LOC genes affecting smell, 3D animation with no audioSite: DNA Interactive (www.dnai.org)

    NSDL National Science Digital Library

    2008-10-06

    DNAi location: Genome>Tour>flyover>Ubiquilin and olfactory receptor cluster The intergenic region is followed by two adjacent ubiquilin genes, which are involved in key cell processes, from replication to \\"programmed\\" death. Ubiquilin 3 is expressed specifically in the testis, where it is believed to help regulate sperm development. These are followed by a cluster of gene locations (LOC) thought to encode olfactory receptors, which receive stimuli in the nose to allow us to detect smells. At 31,110 nucleotides long, the first gene in this cluster, LOC120009, is the longest we will encounter on our journey. Its 11 coding exons are indicated in red, but most of its bulk comes from its yellow introns and 29 blue and purple transposons. However, the majority of olfactory receptors are short. The next four gene locations are more typical of olfactory receptors in having only one or two coding exons. About 60% of our smell receptors are nonfunctional. Presumably, humans have less need for smell in locating food and interacting socially. The mutations that inactivate many receptors vary among people, meaning that there is a DNA basis for the observation that some people can smell better than others! It also suggests that the loss of smelling acuity has occurred very recently in human evolution and is still ongoing.

  10. Associations of Haplotypes Upstream of IRS1 with Insulin Resistance, Type 2 Diabetes, Dyslipidemia, Preclinical Atherosclerosis, and Skeletal Muscle LOC646736 mRNA Levels

    PubMed Central

    Soyal, Selma M.; Felder, Thomas; Auer, Simon; Oberkofler, Hannes; Iglseder, Bernhard; Paulweber, Bernhard; Dossena, Silvia; Nofziger, Charity; Paulmichl, Markus; Esterbauer, Harald; Krempler, Franz; Patsch, Wolfgang

    2015-01-01

    The genomic region ~500?kb upstream of IRS1 has been implicated in insulin resistance, type 2 diabetes, adverse lipid profile, and cardiovascular risk. To gain further insight into this chromosomal region, we typed four SNPs in a cross-sectional cohort and subjects with type 2 diabetes recruited from the same geographic region. From 16 possible haplotypes, 6 haplotypes with frequencies >0.01 were observed. We identified one haplotype that was protective against insulin resistance (determined by HOMA-IR and fasting plasma insulin levels), type 2 diabetes, an adverse lipid profile, increased C-reactive protein, and asymptomatic atherosclerotic disease (assessed by intima media thickness of the common carotid arteries). BMI and total adipose tissue mass as well as visceral and subcutaneous adipose tissue mass did not differ between the reference and protective haplotypes. In 92 subjects, we observed an association of the protective haplotype with higher skeletal muscle mRNA levels of LOC646736, which is located in the same haplotype block as the informative SNPs and is mainly expressed in skeletal muscle, but only at very low levels in liver or adipose tissues. These data suggest a role for LOC646736 in human insulin resistance and warrant further studies on the functional effects of this locus.

  11. The multifunctional application of microfluidic lab-on-a-chip surface enhanced Raman spectroscopy (LOC-SERS) within the field of bioanalytics

    NASA Astrophysics Data System (ADS)

    März, Anne; Mönch, Bettina; Walter, Angela; Bocklitz, Thomas; Schumacher, Wilm; Rösch, Petra; Kiehntopf, Michael; Popp, Jürgen

    2011-07-01

    This contribution will present a variety of applications of lab-on-a-chip surface enhanced Raman spectroscopy in the field of bioanalytic. Beside the quantification and online monitoring of drugs and pharmaceuticals, determination of enzyme activity and discrimination of bacteria are successfully carried out utilizing LOC-SERS. The online-monitoring of drugs using SERS in a microfluidic device is demonstrated for nicotine. The enzyme activity of thiopurine methyltransferase (TPMT) in lysed red blood cells is determined by SERS in a lab-on-a-chip device. To analyse the activity of TPMT the metabolism of 6-mercaptopurine to 6-methylmercaptopurine is investigated. The discrimination of bacteria on strain level is carried out with different E. coli strains. For the investigations, the bacteria are busted by ultra sonic to achieve a high information output. This sample preparation provides the possibility to detect SERS spectra containing information of the bacterial cell walls as well as of the cytoplasm. This contribution demonstrates the great potential of LOC-SERS in the field of bioanalytics.

  12. The similarities between the hallucinations associated with the partial epileptic seizures of the occipital lobe and ball lightning observations

    NASA Astrophysics Data System (ADS)

    Cooray, G. K.; Cooray, V.

    2007-12-01

    Ball Lightning was seen and described since antiquity and recorded in many places. Ball lightning is usually observed during thunderstorms but large number of ball lightning observations is also reported during fine weather without any connection to thunderstorms or lightning. However, so far no one has managed to generate them in the laboratory. It is photographed very rarely and in many cases the authenticity of them is questionable. It is possible that many different phenomena are grouped together and categorized simply as ball lightning. Indeed, the visual hallucinations associated with simple partial epileptic seizures, during which the patient remains conscious, may also be categorized by a patient unaware of his or her condition as ball lightning observation. Such visual hallucinations may occur as a result of an epileptic seizure in the occipital, temporo-occipital or temporal lobes of the cerebrum [1,2,3]. In some cases the hallucination is perceived as a coloured ball moving horizontally from the periphery to the centre of the vision. The ball may appear to be rotating or spinning. The colour of the ball can be red, yellow, blue or green. Sometimes, the ball may appear to have a solid structure surrounded by a thin glow or in other cases the ball appears to generate spark like phenomena. When the ball is moving towards the centre of the vision it may increase its intensity and when it reaches the centre it can 'explode' illuminating the whole field of vision. During the hallucinations the vision is obscured only in the area occupied by the apparent object. The hallucinations may last for 5 to 30 seconds and rarely up to a minute. Occipital seizures may spread into other regions of the brain giving auditory, olfactory and sensory sensations. These sensations could be buzzing sounds, the smell of burning rubber, pain with thermal perception especially in the arms and the face, and numbness and tingling sensation. In some cases a person may experience only one seizure during lifetime and may not be aware of the reason for the experience. Being of good health otherwise, the person may categorize the experience as a ball lightning encounter. If, as described above, the seizure spread into other regions of the brain the resulting experience may appear as electrical effects (the smell, heat sensation, tingling feeling etc.) of ball lightning. Epileptic seizures are a common and important medical problem, with about one in eleven persons experiencing at least one seizure at some point. Thus some of the ball lightning encounters presented in the literature could very well be associated with the experiences of persons who had an epileptic seizure with visual hallucinations. [1] Blom, S. et al., Epilepsy, Neurology, Edited by S-M Aquilonius and J. Fagius, Liber, 2000. [2] Panayiotopoulos, C. P., J. Neorl. Neurosurg. Psychiatry, 66, 536-540, 1999. [3] Bien et al, Brain,123, 244-253, 2000.

  13. Extrastriate cortex: A signature of perception grows.

    PubMed

    Britten, K H

    2001-09-18

    Neuronal activity in area MT of the extrastriate visual cortex is correlated with the choices monkeys make on perceptual tasks. New evidence suggests that this correlation is stronger on some tasks than others. PMID:11566118

  14. A pipeline for interactive cortex segmentation

    Microsoft Academic Search

    Daniela I. Wellein; Silvia Born; Matthias Pfeifle; Frank Duffner; Dirk Bartz

    2011-01-01

    In various clinical or research scenarios, such as neurosurgical intervention planning, diagnostics, or clinical studies concerning\\u000a neurological diseases, cortex segmentation can be of great value. As, e.g., the visualization of the cortical surface along\\u000a with target and risk structures enables conservative access planning and gives context information about the patient-specific\\u000a anatomy. We present an interactive cortex segmentation pipeline (CSP) for

  15. Food related processes in the insular cortex

    PubMed Central

    Frank, Sabine; Kullmann, Stephanie; Veit, Ralf

    2013-01-01

    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 (AN), bulimia nervosa (BN)). 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. PMID:23986683

  16. A layered network model of sensory cortex

    SciTech Connect

    Travis, B.J.

    1986-01-01

    An integrated computational approach to modeling sensory systems which couples realistic layered neural models of sensory cortex and midbrain nuclei to detailed models of the sense organs (e.g., retina or cochlea) is described. The approach is applied to the auditory system. Through an exercise of the model, it is shown that spatial location of sounds may be a natural consequence of the way cochlear response is mapped onto the cortex. 31 refs., 23 figs., 3 tabs.

  17. Atypical neuropathological sCJD-MM phenotype with abundant white matter Kuru-type plaques sparing the cerebellar cortex.

    PubMed

    Gelpi, Ellen; Soler Insa, Josep Ma; Parchi, Piero; Saverioni, Daniela; Yagüe, Jordi; Nos, Carlos; Martínez-Saez, Elena; Ribalta, Teresa; Ferrer, Isidre; Sanchez-Valle, Raquel

    2013-04-01

    We describe an atypical neuropatholgical phenotype of sporadic Creutzfeldt-Jakob disease (sCJD) in a 64-year-old man presenting with a 5-month history of rapidly progressive dementia, comprising behavioral disturbances, memory complaints, disorientation and language alterations. MRI showed diffuse atrophy and hyperintensities in parietal, occipital, temporal and frontal cortices and left caudate nucleus on T2-weighted and fluid-attenuated inversion recovery images. No typical EEG alterations were observed. Repeated 14-3-3 assay was positive after a first negative test. Neuropathology showed classical CJD changes with small cortical foci of large confluent vacuoles and relatively well-preserved cerebellar cortex. The most striking feature was the presence of abundant Kuru-type plaques in both cerebral cortex and subcortical white matter. Sparse Kuru-type plaques were also seen in cerebellum, although only in white matter. Immunohistochemistry showed, in addition to unicentric plaques, diffuse synaptic and patchy perivacuolar, as well as plaque-like and periaxonal pathological prion protein deposits (PrP(res) ). Western blot studies demonstrated the co-occurrence of PrP(res) types 1 and 2 in frontal cortex and a relatively weak type 2 signal in cerebellum. PRNP genotyping revealed methionine homozygosity at codon 129 and excluded mutations. This case shows a previously undescribed combination of histopathological features which preclude its classification according to the current phenotypic and molecular sCJD classification. The observation demonstrates that Kuru-type amyloid plaques mainly involving the cerebral white matter may also occur in sCJD cases with short clinical course and the co-existence of PrP(res) types 1 and 2. This case further highlights the complexity of the correlations between histopathological phenotype and PrP(res) isotype in prion diseases. PMID:22862687

  18. Multisensory maps in parietal cortex?

    PubMed Central

    Sereno, Martin I; Huang, Ruey-Song

    2014-01-01

    Parietal cortex has long been known to be a site of sensorimotor integration. Recent findings in humans have shown that it is divided up into a number of small areas somewhat specialized for eye movements, reaching, and hand movements, but also face-related movements (avoidance, eating), lower body movements, and movements coordinating multiple body parts. The majority of these areas contain rough sensory (receptotopic) maps, including a substantial multisensory representation of the lower body and lower visual field immediately medial to face VIP. There is strong evidence for retinotopic remapping in LIP and face-centered remapping in VIP, and weaker evidence for hand-centered remapping. The larger size of the functionally distinct inferior parietal default mode network in humans compared to monkeys results in a superior and medial displacement of middle parietal areas (e.g., the saccade-related LIP's). Multisensory superior parietal areas located anterior to the angular gyrus such as AIP and VIP are less medially displaced relative to macaque monkeys, so that human LIP paradoxically ends up medial to human VIP. PMID:24492077

  19. Multisensory maps in parietal cortex.

    PubMed

    Sereno, Martin I; Huang, Ruey-Song

    2014-02-01

    Parietal cortex has long been known to be a site of sensorimotor integration. Recent findings in humans have shown that it is divided up into a number of small areas somewhat specialized for eye movements, reaching, and hand movements, but also face-related movements (avoidance, eating), lower body movements, and movements coordinating multiple body parts. The majority of these areas contain rough sensory (receptotopic) maps, including a substantial multisensory representation of the lower body and lower visual field immediately medial to face VIP. There is strong evidence for retinotopic remapping in LIP and face-centered remapping in VIP, and weaker evidence for hand-centered remapping. The larger size of the functionally distinct inferior parietal default mode network in humans compared to monkeys results in a superior and medial displacement of middle parietal areas (e.g., the saccade-related LIP's). Multisensory superior parietal areas located anterior to the angular gyrus such as AIP and VIP are less medially displaced relative to macaque monkeys, so that human LIP paradoxically ends up medial to human VIP. PMID:24492077

  20. Redundancy gains in retinotopic cortex

    PubMed Central

    Jiang, Yuhong V.; Kanwisher, Nancy

    2013-01-01

    It is widely claimed that interactions among simultaneously presented visual stimuli are suppressive and that these interactions primarily occur when stimuli fall within the same receptive field (Desimone and Duncan 1995). Here, we show evidence for a novel form of interaction between simultaneously presented but distant stimuli that does not fit either pattern. To examine interactions between simultaneously presented stimuli, we measure the response to a single stimulus as a function of whether or not other stimuli are also presented simultaneously, and we further ask how the response to a given stimulus is affected by whether the simultaneously present stimuli are identical or different from each other. Our method reveals a new phenomenon of “redundancy gain:” the visual response to a stimulus is higher when accompanied by identical stimuli than when that stimulus is presented alone, even though the stimuli are displayed in separate visual quadrants. This pattern is observed throughout the visual hierarchy, including V1 and V2, and we show that it is distinct from the well-known simultaneous suppression effect (Kastner et al. 1998). We propose that the redundancy gain in early retinotopic cortex results from feedback from higher visual areas and may underlie perceptual averaging and other ensemble coding phenomena observed behaviorally. PMID:23904496

  1. Effect of Visual Feedback on the Occipital-Parietal-Motor Network in Parkinson’s Disease with Freezing of Gait

    PubMed Central

    Velu, Priya D.; Mullen, Tim; Noh, Eunho; Valdivia, Matthew C.; Poizner, Howard; Baram, Yoram; de Sa, Virginia R.

    2014-01-01

    Freezing of gait (FOG) is an elusive phenomenon that debilitates a large number of Parkinson’s disease (PD) patients regardless of stage of disease, medication status, or deep brain stimulation implantation. Sensory feedback cues, especially visual feedback cues, have been shown to alleviate FOG episodes or even prevent episodes from occurring. Here, we examine cortical information flow between occipital, parietal, and motor areas during the pre-movement stage of gait in a PD-with-FOG patient that had a strong positive behavioral response to visual cues, one PD-with-FOG patient without any behavioral response to visual cues, and age-matched healthy controls, before and after training with visual feedback. Results for this case study show differences in cortical information flow between the responding PD-with-FOG patient and the other two subject types, notably, an increased information flow in the beta range. Tentatively suggesting the formation of an alternative cortical sensory-motor pathway during training with visual feedback, these results are proposed as subject for further verification employing larger cohorts of patients. PMID:24409167

  2. R + C Factors and Sacro Occipital Technique Orthopedic Blocking: a pilot study using pre and post VAS assessment

    PubMed Central

    Blum, Charles L.

    2015-01-01

    Introduction: The concept of a systematic or predictive relationship between distant vertebral levels distinct from accumulative functional compensatory mechanisms, such as in scoliosis, has been perpetuated within chiropractic technique systems based on clinical observation and experience. This study seeks to investigate this relationship between the cervical and lumbar vertebrae. Methods: Patients (experimental group n=26 and control group n=12) were selected from the patient base of one office, and were limited to patients that had sensitivity at specific cervical reflex points. Using a pre and post outcome measurement and sacro occipital technique R + C protocols, the related lumbar vertebra was adjusted in the direction indicated by the cervical vertebral sensitivity. Results: Statistical analysis revealed there was a statistically significant difference between pre- and post-VAS measurements and found that the notable difference in mean change in VAS scores were statistically significantly different between the experimental and control groups (p < .001). Conclusion: The findings of this study suggest that further research into cervical and lumbar vertebra interrelationships, and the efficacy of orthopedic block treatment, may be warranted. Further studies are needed to confirm whether a causal relationship exists between lumbar manipulation and decreased cervical spine sensitivity. PMID:26136605

  3. Age-Group Differences in Medial Cortex Activity Associated With Thinking About Self-Relevant Agendas

    E-print Network

    Johnson, Marcia K.

    cognitive processes that are engaged by complex self-reflection and mediated by prefrontal cortex. Keywords: self-reflection, aging, medial prefrontal cortex, posterior cingulate cortex, precuneus Self

  4. Perirhinal cortex and temporal lobe epilepsy

    PubMed Central

    Biagini, Giuseppe; D'Antuono, Margherita; Benini, Ruba; de Guzman, Philip; Longo, Daniela; Avoli, Massimo

    2013-01-01

    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. PMID:24009554

  5. Auditory connections and functions of prefrontal cortex

    PubMed Central

    Plakke, Bethany; Romanski, Lizabeth M.

    2014-01-01

    The functional auditory system extends from the ears to the frontal lobes with successively more complex functions occurring as one ascends the hierarchy of the nervous system. Several areas of the frontal lobe receive afferents from both early and late auditory processing regions within the temporal lobe. Afferents from the early part of the cortical auditory system, the auditory belt cortex, which are presumed to carry information regarding auditory features of sounds, project to only a few prefrontal regions and are most dense in the ventrolateral prefrontal cortex (VLPFC). In contrast, projections from the parabelt and the rostral superior temporal gyrus (STG) most likely convey more complex information and target a larger, widespread region of the prefrontal cortex. Neuronal responses reflect these anatomical projections as some prefrontal neurons exhibit responses to features in acoustic stimuli, while other neurons display task-related responses. For example, recording studies in non-human primates indicate that VLPFC is responsive to complex sounds including vocalizations and that VLPFC neurons in area 12/47 respond to sounds with similar acoustic morphology. In contrast, neuronal responses during auditory working memory involve a wider region of the prefrontal cortex. In humans, the frontal lobe is involved in auditory detection, discrimination, and working memory. Past research suggests that dorsal and ventral subregions of the prefrontal cortex process different types of information with dorsal cortex processing spatial/visual information and ventral cortex processing non-spatial/auditory information. While this is apparent in the non-human primate and in some neuroimaging studies, most research in humans indicates that specific task conditions, stimuli or previous experience may bias the recruitment of specific prefrontal regions, suggesting a more flexible role for the frontal lobe during auditory cognition. PMID:25100931

  6. Dynamic Representation of Eye Position in the Parieto-Occipital Sulcus K. NAKAMURA, H. H. CHUNG, M.S.A. GRAZIANO, AND C. G. GROSS

    E-print Network

    Graziano, Michael

    of the position of the eye in the orbit, but this repre- sentation appears to be dynamic, emphasizing the arrival of the eye at a new position. I N T R O D U C T I O N The position of the eyes in the orbits affectsDynamic Representation of Eye Position in the Parieto-Occipital Sulcus K. NAKAMURA, H. H. CHUNG, M

  7. fMRI Measures of perceptual filling-in in the human visual cortex.

    PubMed

    Mendola, J D; Conner, I P; Sharma, S; Bahekar, A; Lemieux, S

    2006-03-01

    Filling-in refers to the tendency of stabilized retinal stimuli to fade and become replaced by their background. This phenomenon is a good example of central brain mechanisms that can selectively add or delete information to/from the retinal input. Importantly, such cortical mechanisms may overlap with those that are used more generally in visual perception. In order to identify cortical areas that contribute to perceptual filling-in, we used functional magnetic resonance imaging to image activity in the visual cortex while subjects experienced filling-in. Nine subjects viewed an achromatic disc with slightly higher luminance than the background and indicated the presence or absence of filling-in by a keypress. The disc was placed in either the upper or lower left quadrant. Similar high-contrast stimuli were used to map out the retinotopic representation of the disc. Unexpectedly, the lower-field high-contrast stimulus produced more parietal cortex activation than the upper-field condition, indicating preferential representation of the lower field by attentional control mechanisms. During perceptual filling-in, we observed significant contralateral reductions in activation in lower-tier retinotopic areas V1 and V2. In contrast, increased activation was consistently observed in visual areas V3A and V4v, higher-level cortex in the intraparietal sulcus, posterior superior temporal sulcus, and the ventral occipital-temporal region, as well as the pulvinar. The filling-in activation pattern was remarkably similar for both the upper- and lower-field conditions. Behaviorally, filling-in was reported to be easier for the lower visual field, and filling-in periods were longer for the lower than the upper quadrant. We suggest this behavioral asymmetry may be partially due to the preferential parietal representation of the lower field. The results lead us to propose that perceptual filling-in recruits high-level control mechanisms to reconcile competing percepts, and alters the normal image-related signals at the first stages of cortical processing. Moreover, the overall pattern of activation during filling-in resembles that seen in other studies of perceptually bistable stimuli, including binocular rivalry, indicating common control mechanisms. PMID:16513002

  8. Functional role and mechanism of lncRNA LOC728228 in malignant 16HBE cells transformed by anti-benzopyrene-trans-7,8-dihydrodiol-9,10-epoxide.

    PubMed

    Hu, Gongcheng; Yang, Ti; Zheng, Jingli; Dai, Jiabing; Nan, Aruo; Lai, Yandong; Zhang, Yajie; Yang, Chengfeng; Jiang, Yiguo

    2015-06-01

    Lung cancer is a major health problem, and is considered one of the deadliest cancers in humans. It is refractory to current treatments, and the mechanisms of lung cancer are unknown. Long noncoding RNAs (lncRNAs) are involved in various biological processes and human diseases. However, the exact functional roles and mechanisms of lncRNAs are largely unclear. In this study, we attempted to identify lung-cancer-related lncRNAs. We found changes in lncRNA expression in the anti-benzo(a) pyrene-7,8-diol-9,10-epoxide (anti-BPDE)-transformed human bronchial epithelial cell line (16HBE-T cells) using microarrays and qRT-PCR. Of these lncRNAs, LOC728228 was upregulated relative to its expression in control untransformed16HBE (16HBE-N) cells. LOC728228 knockdown inhibited cell proliferation, caused G0/G1-phase cell-cycle arrest, reduced cellular migration, suppressed colony formation in vitro, and inhibited tumor growth in a nude mouse xenograft model. LOC728228 knockdown also suppressed cyclin D1 expression, and the depletion of cyclin D1 induced G0/G1-phase cell-cycle arrest and inhibited cell proliferation, thus influencing the malignant potential of cancer cells. In summary, our results suggest that lncRNA LOC728228 has an oncogene-like function and plays a vital role in human lung cancer. © 2015 Wiley Periodicals, Inc. PMID:25820656

  9. Please cite this article in press as: Pitcher, D., et al. The role of lateral occipital face and object areas in the face inversion effect. Neuropsychologia (2011), doi:10.1016/j.neuropsychologia.2011.08.020

    E-print Network

    Kanwisher, Nancy

    2011-01-01

    Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA b Institute of Cognitive: Face perception Object recognition Transcranial magnetic stimulation Occipital face area Lateral facial features at an early stage of face processing. © 2011 Elsevier Ltd. All rights reserved. 1

  10. The functions of the orbitofrontal cortex.

    PubMed

    Rolls, Edmund T

    2004-06-01

    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 of objects from the temporal lobe cortical visual areas, and neurons in it learn and reverse the visual stimulus to which they respond when the association of the visual stimulus with a primary reinforcing stimulus (such as taste) is reversed. This is an example of stimulus-reinforcement association learning, and is a type of stimulus-stimulus association learning. More generally, the stimulus might be a visual or olfactory stimulus, and the primary (unlearned) positive or negative reinforcer a taste or touch. A somatosensory input is revealed by neurons that respond to the texture of food in the mouth, including a population that responds to the mouth feel of fat. In complementary neuroimaging studies in humans, it is being found that areas of the orbitofrontal cortex are activated by pleasant touch, by painful touch, by taste, by smell, and by more abstract reinforcers such as winning or losing money. Damage to the orbitofrontal cortex can impair the learning and reversal of stimulus-reinforcement associations, and thus the correction of behavioural responses when there are no longer appropriate because previous reinforcement contingencies change. The information which reaches the orbitofrontal cortex for these functions includes information about faces, and damage to the orbitofrontal cortex can impair face (and voice) expression identification. This evidence thus shows that the orbitofrontal cortex is involved in decoding and representing some primary reinforcers such as taste and touch; in learning and reversing associations of visual and other stimuli to these primary reinforcers; and in controlling and correcting reward-related and punishment-related behavior, and thus in emotion. The approach described here is aimed at providing a fundamental understanding of how the orbitofrontal cortex actually functions, and thus in how it is involved in motivational behavior such as feeding and drinking, in emotional behavior, and in social behavior. PMID:15134840

  11. Anatomic organization of the auditory cortex.

    PubMed

    Hackett, Troy A

    2015-01-01

    The auditory cortex is a network of areas in the part of the brain that receives inputs from the subcortical auditory pathways in the brainstem and thalamus. Through an elaborate network of intrinsic and extrinsic connections, the auditory cortex is thought to bring about the conscious perception of sound and provide a basis for the comprehension and production of meaningful utterances. In this chapter, the organization of auditory cortex is described with an emphasis on its anatomic features and the flow of information within the network. These features are then used to introduce key neurophysiologic concepts that are being intensively studied in humans and animal models. The discussion is presented in the context of our working model of the primate auditory cortex and extensions to humans. The material is presented in the context of six underlying principles, which reflect distinct, but related, aspects of anatomic and physiologic organization: (1) the division of auditory cortex into regions; (2) the subdivision of regions into areas; (3) tonotopic organization of areas; (4) thalamocortical connections; (5) serial and parallel organization of connections; and (6) topographic relationships between auditory and auditory-related areas. Although the functional roles of the various components of this network remain poorly defined, a more complete understanding is emerging from ongoing studies that link auditory behavior to its anatomic and physiologic substrates. PMID:25726261

  12. Long-range functional interactions of anterior insula and medial frontal cortex are differently modulated by visuospatial and inductive reasoning tasks.

    PubMed

    Ebisch, Sjoerd J H; Mantini, Dante; Romanelli, Roberta; Tommasi, Marco; Perrucci, Mauro G; Romani, Gian Luca; Colom, Roberto; Saggino, Aristide

    2013-09-01

    The brain is organized into functionally specific networks as characterized by intrinsic functional relationships within discrete sets of brain regions. However, it is poorly understood whether such functional networks are dynamically organized according to specific task-states. The anterior insular cortex (aIC)-dorsal anterior cingulate cortex (dACC)/medial frontal cortex (mFC) network has been proposed to play a central role in human cognitive abilities. The present functional magnetic resonance imaging (fMRI) study aimed at testing whether functional interactions of the aIC-dACC/mFC network in terms of temporally correlated patterns of neural activity across brain regions are dynamically modulated by transitory, ongoing task demands. For this purpose, functional interactions of the aIC-dACC/mFC network are compared during two distinguishable fluid reasoning tasks, Visualization and Induction. The results show an increased functional coupling of bilateral aIC with visual cortices in the occipital lobe during the Visualization task, whereas coupling of mFC with right anterior frontal cortex was enhanced during the Induction task. These task-specific modulations of functional interactions likely reflect ability related neural processing. Furthermore, functional connectivity strength between right aIC and right dACC/mFC reliably predicts general task performance. The findings suggest that the analysis of long-range functional interactions may provide complementary information about brain-behavior relationships. On the basis of our results, it is proposed that the aIC-dACC/mFC network contributes to the integration of task-common and task-specific information based on its within-network as well as its between-network dynamic functional interactions. PMID:23624492

  13. Sexual differentiation of mammalian frontal cortex

    SciTech Connect

    Maggi, A.; Zucchi, I.

    1987-03-23

    The pattern of distribution of the progesterone binding sites was examined in selected nuclei of the brain of male and female rat. In female rats the frontal cortex resulted to be the region with the highest concentration of /sup 3/H R5020 biding sites. However, in male rats the same region showed very little progestin binding activity. When female rats were androgenized via neonatal exposure to testosterone, the progestin binding activity of the frontal cortex became similar to that observed in male rats. The present investigation indicates that sexual differentiation of the rat brain may include also brain regions not clearly involved in sex related functions like the frontal cortex. 30 references, 2 figures, 1 table.

  14. Nicotine and Synaptic Plasticity in Prefrontal Cortex

    NSDL National Science Digital Library

    Daniel S. McGehee (University of Chicago; Department of Anesthesia and Critical Care REV)

    2007-08-14

    Nicotinic receptor activation enhances working memory and attention. The prefrontal cortex is a key brain area involved in working memory, and plasticity of excitatory synaptic transmission within the cortex is likely an important cellular mechanism of memory. A recent study has explored the cellular and synaptic basis of nicotine’s effects on excitability within the prefrontal cortex. The findings suggest that nicotine enhances inhibitory synaptic inputs to layer V pyramidal cells, which suppresses induction of long-term potentiation (LTP). This inhibitory effect can be overcome by stimulating the pyramidal cells in bursts, which suggests a modification in the signal-to-noise ratio for synaptic input. Thus, the impact of strong stimuli on working memory would be enhanced when combined with nicotinic receptor activity. These findings may lead to novel and more effective treatments for memory disorders.

  15. A neuronal model of the language cortex

    Microsoft Academic Search

    Max Garagnani; Thomas Wennekers; Friedemann Pulvermüller

    2007-01-01

    Abstract We modelled,language-learning processes in a brain-inspired model,of the language,cortex. The network,consisted of neuron-like elements,(graded-response units) and,mimicked,the neuroanatomical,areas in the perisylvian language,cortex and,the intrinsic and mutual,connections,within and,between,them. Speaking words,creates correlated activity in motor,and auditory,cortical systems. This correlated activity might play an important role in setting up word representations at the neuronal level [D.B. Fry, The development of the phonological system

  16. Progenitor genealogy in the developing cerebral cortex.

    PubMed

    Laguesse, Sophie; Peyre, Elise; Nguyen, Laurent

    2015-01-01

    The mammalian cerebral cortex is characterized by a complex histological organization that reflects the spatio-temporal stratifications of related stem and neural progenitor cells, which are responsible for the generation of distinct glial and neuronal subtypes during development. Some work has been done to shed light on the existing filiations between these progenitors as well as their respective contribution to cortical neurogenesis. The aim of the present review is to summarize the current views of progenitor hierarchy and relationship in the developing cortex and to further discuss future research directions that would help us to understand the molecular and cellular regulating mechanisms involved in cerebral corticogenesis. PMID:25141969

  17. A Survey on ARM Cortex A Overview of ARM Processors

    E-print Network

    Skadron, Kevin

    Focusing on Cortex A9 & Cortex A15 ARM ships no processors but only IP cores For SoC integration the flexibility to emphasize performance or code size "Thumb-aware" core is a standard ARM processor fitted1 A Survey on ARM Cortex A Processors Wei Wang Tanima Dey #12;2 Overview of ARM Processors

  18. Anxiety and Affective Style: Role of Prefrontal Cortex and Amygdala

    E-print Network

    Wisconsin at Madison, University of

    Anxiety and Affective Style: Role of Prefrontal Cortex and Amygdala Richard J. Davidson Psychiatry Key Words: Anxiety, affective style, prefrontal cortex, amygdala Introduction Biobehavioral: the prefrontal cortex (PFC) and the amygdala. There are several differ- ent functional divisions of the PFC

  19. The Discovery of Motor Cortex and its Background

    Microsoft Academic Search

    Charles G. Gross

    2007-01-01

    In 1870 Gustav Fritsch and Edvard Hitzig showed that electrical stimulation of the cerebral cortex of a dog produced movements. This was a crucial event in the development of modern neuroscience because it was the first good experimental evidence for a) cerebral cortex involvement in motor function, b) the electrical excitability of the cortex, c) topographic representation in the brain,

  20. Cell Counts in Cerebral Cortex of an Autistic Patient.

    ERIC Educational Resources Information Center

    Coleman, Paul D.; And Others

    1985-01-01

    Numbers of neurons and glia were counted in the cerebral cortex of one case of autism and two age- and sex-matched controls. Cell counts were made in primary auditory cortex, Broca's speech area, and auditory association cortex. No consistent differences in cell density were found between brains of autistic and control patients. (Author/CL)

  1. The neuropsychological impact of insular cortex lesions

    Microsoft Academic Search

    Catherine L Jones; Jamie Ward; Hugo D Critchley

    2010-01-01

    Influential models based on an increasing body of neuroimaging evidence propose that insular cortex integrates cognitive, affective, sensory and autonomic information to create a consciously perceived, ‘feeling state.’ To appraise these models and evaluate interpretations of neuroimaging findings, the authors review evidence pertaining to the psychological and behavioural consequences of insula lesions. The authors focus on the emotional, perceptual, sensorimotor

  2. Excitatory neuronal connectivity in the barrel cortex

    PubMed Central

    Feldmeyer, Dirk

    2012-01-01

    Neocortical areas are believed to be organized into vertical modules, the cortical columns, and the horizontal layers 1–6. In the somatosensory barrel cortex these columns are defined by the readily discernible barrel structure in layer 4. Information processing in the neocortex occurs along vertical and horizontal axes, thereby linking individual barrel-related columns via axons running through the different cortical layers of the barrel cortex. Long-range signaling occurs within the neocortical layers but also through axons projecting through the white matter to other neocortical areas and subcortical brain regions. Because of the ease of identification of barrel-related columns, the rodent barrel cortex has become a prototypical system to study the interactions between different neuronal connections within a sensory cortical area and between this area and other cortical as well subcortical regions. Such interactions will be discussed specifically for the feed-forward and feedback loops between the somatosensory and the somatomotor cortices as well as the different thalamic nuclei. In addition, recent advances concerning the morphological characteristics of excitatory neurons and their impact on the synaptic connectivity patterns and signaling properties of neuronal microcircuits in the whisker-related somatosensory cortex will be reviewed. In this context, their relationship between the structural properties of barrel-related columns and their function as a module in vertical synaptic signaling in the whisker-related cortical areas will be discussed. PMID:22798946

  3. Reorganization of Auditory Cortex in Tinnitus

    Microsoft Academic Search

    Werner Muhlnickel; Thomas Elbert; Edward Taub; Herta Flor

    1998-01-01

    Magnetic source imaging was used to determine whether tonotopy in auditory cortex of individuals with tinnitus diverges from normative functional organization. Ten tinnitus subjects and 15 healthy controls were exposed to four sets of tones while magnetoencephalographic recordings were obtained from the two cortical hemispheres in sequence. A marked shift of the cortical representation of the tinnitus frequency into an

  4. Frequency Change Detection in Human Auditory Cortex

    Microsoft Academic Search

    Patrick May; Hannu Tiitinen; Risto J. Ilmoniemi; Göte Nyman; John G. Taylor; Risto Näätänen

    1999-01-01

    We offer a model of how human cortex detects changes in the auditory environment. Auditory change detection has recently been the object of intense investigation via the mismatch negativity (MMN). MMN is a preattentive response to sudden changes in stimulation, measured noninvasively in the electroencephalogram (EEG) and the magnetoencephalogram (MEG). It is elicited in the oddball paradigm, where infrequent deviant

  5. Stochastic Multiple Stream Decoding of Cortex Codes

    Microsoft Academic Search

    Matthieu Arzel; Cyril Lahuec; Christophe Jego; Warren J. Gross; Yvain Bruned

    2011-01-01

    Being one of the most efficient solutions to implement forward error correction (FEC) decoders based on belief propagation, stochastic processing is thus a method worthy of consideration when addressing the decoding of emerging codes such as Cortex codes. This code family offers short block codes with large Hamming distances. Unfortunately, their con- struction introduces many hidden variables making them difficult

  6. Relative reward preference in primate orbitofrontal cortex.

    PubMed

    Tremblay, L; Schultz, W

    1999-04-22

    The orbital part of prefrontal cortex appears to be crucially involved in the motivational control of goal-directed behaviour. Patients with lesions of orbitofrontal cortex show impairments in making decisions about the expected outcome of actions. Monkeys with orbitofrontal lesions respond abnormally to changes in reward expectations and show altered reward preferences. As rewards constitute basic goals of behaviour, we investigated here how neurons in the orbitofrontal cortex of monkeys process information about liquid and food rewards in a typical frontal task, spatial delayed responding. The activity of orbitofrontal neurons increases in response to reward-predicting signals, during the expectation of rewards, and after the receipt of rewards. Neurons discriminate between different rewards, mainly irrespective of the spatial and visual features of reward-predicting stimuli and behavioural reactions. Most reward discriminations reflect the animals' relative preference among the available rewards, as expressed by their choice behaviour, rather than physical reward properties. Thus, neurons in the orbitofrontal cortex appear to process the motivational value of rewarding outcomes of voluntary action. PMID:10227292

  7. Theory of Orientation Tuning in Visual Cortex

    Microsoft Academic Search

    R. Ben-Yishai; R. Lev Bar-Or; H. Sompolinsky

    1995-01-01

    The role of intrinsic cortical connections in processing sensory input and in generating behavioral output is poorly understood. We have examined this issue in the context of the tuning of neuronal responses in cortex to the orientation of a visual stimulus. We analytically study a simple network model that incorporates both orientation-selective input from the lateral geniculate nucleus and orientation-specific

  8. Auditory processing in primate cerebral cortex

    Microsoft Academic Search

    Jon H Kaas; Troy A Hackett; Mark Jude Tramo

    1999-01-01

    Auditory information is relayed from the ventral nucleus of the medial geniculate complex to a core of three primary or primary-like areas of auditory cortex that are cochleotopically organized and highly responsive to pure tones. Auditory information is then distributed from the core areas to a surrounding belt of about seven areas that are less precisely cochleotopic and generally more

  9. Microglia in the Cerebral Cortex in Autism

    ERIC Educational Resources Information Center

    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…

  10. Motor Cortex Reorganization across the Lifespan

    ERIC Educational Resources Information Center

    Plowman, Emily K.; Kleim, Jeffrey A.

    2010-01-01

    The brain is a highly dynamic structure with the capacity for profound structural and functional change. Such neural plasticity has been well characterized within motor cortex and is believed to represent one of the neural mechanisms for acquiring and modifying motor behaviors. A number of behavioral and neural signals have been identified that…

  11. Cognitive Neurophysiology of the Motor Cortex

    Microsoft Academic Search

    Apostolos P. Georgopoulos; Masato Taira; Alexander Lukashin

    1993-01-01

    A major challenge of current neuroscience is to elucidate the brain mechanisms that underlie cognitive function. There is no doubt that cognitive processing in the brain engages large populations of cells. This article explores the logic of investigating these problems by combining psychological studies in human subjects and neurophysiological studies of neuronal populations in the motor cortex of behaving monkeys.

  12. The insular cortex: a comparative perspective.

    PubMed

    Butti, Camilla; Hof, Patrick R

    2010-06-01

    The human insular cortex is involved in a variety of viscerosensory, visceromotor, and interoceptive functions, and plays a role in complex processes such as emotions, music, and language. Across mammals, the insula has considerable morphologic variability. We review the structure and connectivity of the insula in laboratory animals (mouse, domestic cat, macaque monkey), and we present original data on the morphology and cytoarchitecture of insular cortex in less common species including a large carnivore (the Atlantic walrus, Odobenus rosmarus), two artiodactyls (the pigmy hippopotamus, Hexaprotodon liberiensis, and the Western bongo, Tragelaphus eurycerus), two cetaceans (the beluga whale, Delphinapterus leucas, and the minke whale, Balaenoptera acutorostrata), and a sirenian (the Florida manatee, Trichechus manatus latirostris). The insula shows substantial variability in shape, extent, and gyral and sulcal patterns, as well as differences in laminar organization, cellular specialization, and structural association with the claustrum. Our observations reveal that the insular cortex is extremely variable among mammals. These differences could be related to the role exerted by specific and selective pressures on cortical structure during evolution. We conclude that it is not possible to identify a general model of organization for the mammalian insular cortex. PMID:20512368

  13. Visual cortex: cartography, connectivity, and concurrent processing.

    PubMed

    Knierim, J J; Van Essen, D C

    1992-04-01

    The mammalian visual cortex contains a complex mosaic of areas that are richly connected with one another. Recent progress has advanced our understanding of both macroscopic and microscopic aspects of cortical organization, and of information flow within and between functionally specialized processing streams. PMID:1638145

  14. A Computational Model of the Cerebral Cortex

    Microsoft Academic Search

    Thomas Dean

    2005-01-01

    Our current understanding of the primate cerebral cor- tex (neocortex) and in particular the posterior, sensory association cortex has matured to a point where it is possible to develop a family of graphical models that capture the structure, scale and power of the neocor- tex for purposes of associative recall, sequence predic- tion and pattern completion among other functions. Im-

  15. Testosterone reduces amygdala–orbitofrontal cortex coupling

    Microsoft Academic Search

    Guido van Wingen; Claudia Mattern; Robbert Jan Verkes; Jan Buitelaar; Guillén Fernández

    2010-01-01

    Testosterone influences various aspects of affective behavior, which is mediated by different brain regions within the emotion circuitry. Previous neuroimaging studies have demonstrated that testosterone increases neural activity in the amygdala. To investigate whether this could be due to altered regulation of amygdala functioning which is thought to be mediated by the prefrontal cortex, we studied the effects of exogenous

  16. Auditory motion processing after early blindness

    PubMed Central

    Jiang, Fang; Stecker, G. Christopher; Fine, Ione

    2014-01-01

    Studies showing that occipital cortex responds to auditory and tactile stimuli after early blindness are often interpreted as demonstrating that early blind subjects “see” auditory and tactile stimuli. However, it is not clear whether these occipital responses directly mediate the perception of auditory/tactile stimuli, or simply modulate or augment responses within other sensory areas. We used fMRI pattern classification to categorize the perceived direction of motion for both coherent and ambiguous auditory motion stimuli. In sighted individuals, perceived motion direction was accurately categorized based on neural responses within the planum temporale (PT) and right lateral occipital cortex (LOC). Within early blind individuals, auditory motion decisions for both stimuli were successfully categorized from responses within the human middle temporal complex (hMT+), but not the PT or right LOC. These findings suggest that early blind responses within hMT+ are associated with the perception of auditory motion, and that these responses in hMT+ may usurp some of the functions of nondeprived PT. Thus, our results provide further evidence that blind individuals do indeed “see” auditory motion. PMID:25378368

  17. Rhinal Cortex Lesions and Emotional Responses 1 COMPARISON OF EMOTIONAL RESPONSES IN MONKEYS WITH RHINAL CORTEX OR AMYGDALA LESIONS

    E-print Network

    Paris-Sud XI, Université de

    WITH RHINAL CORTEX OR AMYGDALA LESIONS Martine Meunier (Institut des Sciences Cognitives, CNRS, Bron, France neurotoxic or aspiration lesions of the neighboring amygdala. Rhinal cortex ablations yielded several subtle following amygdala damage. These findings raise the possibility that the rhinal cortex and amygdala have

  18. Anatomo-functional study of the temporo-parieto-occipital region: dissection, tractographic and brain mapping evidence from a neurosurgical perspective.

    PubMed

    De Benedictis, Alessandro; Duffau, Hugues; Paradiso, Beatrice; Grandi, Enrico; Balbi, Sergio; Granieri, Enrico; Colarusso, Enzo; Chioffi, Franco; Marras, Carlo Efisio; Sarubbo, Silvio

    2014-08-01

    The temporo-parieto-occipital (TPO) junction is a complex brain territory heavily involved in several high-level neurological functions, such as language, visuo-spatial recognition, writing, reading, symbol processing, calculation, self-processing, working memory, musical memory, and face and object recognition. Recent studies indicate that this area is covered by a thick network of white matter (WM) connections, which provide efficient and multimodal integration of information between both local and distant cortical nodes. It is important for neurosurgeons to have good knowledge of the three-dimensional subcortical organisation of this highly connected region to minimise post-operative permanent deficits. The aim of this dissection study was to highlight the subcortical functional anatomy from a topographical surgical perspective. Eight human hemispheres (four left, four right) obtained from four human cadavers were dissected according to Klingler's technique. Proceeding latero-medially, the authors describe the anatomical courses of and the relationships between the main pathways crossing the TPO. The results obtained from dissection were first integrated with diffusion tensor imaging reconstructions and subsequently with functional data obtained from three surgical cases, all resection of infiltrating glial tumours using direct electrical mapping in awake patients. The subcortical limits for performing safe lesionectomies within the TPO region are as follows: within the parietal region, the anterior horizontal part of the superior longitudinal fasciculus and, more deeply, the arcuate fasciculus; dorsally, the vertical projective thalamo-cortical fibres. For lesions located within the temporal and occipital lobes, the resection should be tailored according to the orientation of the horizontal associative pathways (the inferior fronto-occipital fascicle, inferior longitudinal fascicle and optic radiation). The relationships between the WM tracts and the ventricle system were also examined. These results indicate that a detailed anatomo-functional awareness of the WM architecture within the TPO area is mandatory when approaching intrinsic brain lesions to optimise surgical results and to minimise post-operative morbidity. PMID:24975421

  19. Potential of Pretreatment Neural Activity in the Visual Cortex During Emotional Processing to Predict Treatment Response to Scopolamine in Major Depressive Disorder

    PubMed Central

    Furey, Maura L.; Drevets, Wayne C.; Hoffman, Elana M.; Frankel, Erica; Speer, Andrew M.; Zarate, Carlos A.

    2013-01-01

    Context The need for improved treatment options for patients with major depressive disorder (MDD) is critical. Faster-acting antidepressants and biomarkers that predict clinical response will facilitate treatment. Scopolamine produces rapid antidepressant effects and thus offers the opportunity to characterize potential biomarkers of treatment response within short periods. Objective To determine if baseline brain activity when processing emotional information can predict treatment response to scopolamine in MDD. Design A double-blind, placebo-controlled, crossover study together with repeated functional magnetic resonance imaging, acquired as participants performed face-identity and face-emotion working memory tasks. Setting National Institute of Mental Health Division of Intramural Research Programs. Participants Fifteen currently depressed outpatients meeting DSM-IV criteria for recurrent MDD and 21 healthy participants, between 18 and 55 years of age. Main Outcome Measure The magnitude of treatment response to scopolamine (percentage of change in the Montgomery-Asberg Depression Rating Scale score between study end and baseline) was correlated with blood oxygen level–dependent (BOLD) signal associated with each working memory component (encode, maintenance, and test) for both identity and emotion tasks. Treatment response also was correlated with change in BOLD response (scopolamine vs baseline). Baseline activity was compared between healthy and MDD groups. Results Baseline BOLD response in the bilateral middle occipital cortex, selectively during the stimulus-processing components of the emotion working memory task (no correlation during the identity task), correlated with treatment response magnitude. Change in BOLD response following scopolamine administration in overlapping areas in the middle occipital cortex while performing the same task conditions also correlated with clinical response. Healthy controls showed higher activity in the same visual regions than patients with MDD during baseline. Conclusion These results implicate cholinergic and visual processing dysfunction in the pathophysiology of MDD and suggest that neural response in the visual cortex, selectively to emotional stimuli, may provide a useful biomarker for identifying patients who will respond favorably to scopolamine. Trial Registration clinicaltrials.gov Identifier: NCT00055575 PMID:23364679

  20. Differential rearing effects on rat visual cortex synapses. II. Synaptic morphometry.

    PubMed

    Sirevaag, A M; Greenough, W T

    1985-04-01

    An array of morphological measurements was made upon spine synapses in the upper 4 layers of occipital cortex of rats reared for 30 days after weaning in complex (EC), social (SC) or isolated (IC) environments. The mean length of the synaptic contact zone (post-synaptic density plus interpolated non-impregnated regions) was greater in layer IV of EC rats than in IC rats. SC rats were intermediate, not differing from other groups. There were no differences in these measures in other layers, nor were there differences in the mean area or perimeter of presynaptic terminals or postsynaptic processes, the relative frequency of headed vs sessile shaped spines, the length of the apposition between pre- and postsynaptic processes, or the ratio of perimeter to area (inverse roundness) of postsynaptic processes. Cleft width was greater in regions of the contact zone where postsynaptic density was present than in regions where it was absent (perforations), but, aside from the previously described differences in the frequency of perforated synapses, there were no group differences in cleft width. The maximum length of synaptic contact zones and the maximum area of presynaptic terminals was greater in EC than in IC rats in layer IV, but not in other layers, with SC rats again intermediate. These results support previous findings of larger layer IV synaptic contacts in EC rats and suggest that the size of some synaptic components can change without changes in others, a population of very large synapses is seen in layer IV of EC rats that is not seen in IC rats, and perforations may be unlikely sites of synapse splitting, given that membranes are more closely apposed in these regions, rather than pulling apart. PMID:3995348

  1. Inhibitory repetitive transcranial magnetic stimulation (rTMS) of the dorsolateral prefrontal cortex modulates early affective processing.

    PubMed

    Zwanzger, Peter; Steinberg, Christian; Rehbein, Maimu Alissa; Bröckelmann, Ann-Kathrin; Dobel, Christian; Zavorotnyy, Maxim; Domschke, Katharina; Junghöfer, Markus

    2014-11-01

    The dorsolateral prefrontal cortex (dlPFC) has often been suggested as a key modulator of emotional stimulus appraisal and regulation. Therefore, in clinical trials, it is one of the most frequently targeted regions for non-invasive brain stimulation such as repetitive transcranial magnetic stimulation (rTMS). In spite of various encouraging reports that demonstrate beneficial effects of rTMS in anxiety disorders, psychophysiological studies exploring the underlying neural mechanisms are sparse. Here we investigated how inhibitory rTMS influences early affective processing when applied over the right dlPFC. Before and after rTMS or sham stimulation, subjects viewed faces with fearful or neutral expressions while whole-head magnetoencephalography (MEG) was recorded. Due to the disrupted functioning of the right dlPFC, visual processing in bilateral parietal, temporal, and occipital areas was amplified starting at around 90 ms after stimulus onset. Moreover, increased fear-specific activation was found in the right TPJ area in a time-interval between 110 and 170 ms. These neurophysiological effects were reflected in slowed reaction times for fearful, but not for neutral faces in a facial expression identification task while there was no such effect on a gender discrimination control task. Our study confirms the specific and important role of the dlPFC in regulation of early emotional attention and encourages future clinical research to use minimal invasive methods such as transcranial magnetic (TMS) or direct current stimulation (tDCS). PMID:25019678

  2. Plasticity of GFAP-immunoreactive astrocyte size and number in visual cortex of rats reared in complex environments.

    PubMed

    Sirevaag, A M; Greenough, W T

    1991-02-01

    Previous studies have indicated effects of postweaning rearing environment complexity on astrocyte nuclei. This study examined the effects of rearing for 10, 30 or 67 days in a complex (EC), social (SC) or individual cage (IC) environment upon glial fibrillary acidic protein (GFAP) immunoreactive astrocytes of the occipital cortex. EC rats exposed to their environment for 30 days or longer had a greater surface density of astrocytic processes (Sv) than SC or IC rats. The greater surface density of EC cortical astrocytes appeared to be due to an increase in the mean size of astrocytes after 30 days of differential environmental exposure. After 67 days of environmental exposure, however, the greater Sv appeared to be due to an increase in the number of astrocytes. Astrocytic plasticity appears to develop rather slowly during exposure to a complex environment and appears to involve two stages. The first stage is a hypertrophy of existing astrocytes and the second stage involves proliferation or retarded death of astrocytes. These changes may be related to brain information processing since astrocytes are known modulators of synaptic activity and may possibly serve as regulators of synaptic density. PMID:2054618

  3. Social Distance Evaluation in Human Parietal Cortex

    PubMed Central

    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. PMID:19204791

  4. Dopamine gates sensory representations in cortex

    PubMed Central

    Tian, Ju

    2014-01-01

    The prefrontal cortex (PFC) maintains information about relevant sensory stimuli, in a process thought to rely on dopamine release. In a recent paper, Jacob et al. (J Neurosci 33: 13724–13734, 2013) demonstrated one way in which dopamine might facilitate this process. The authors recorded from PFC neurons in monkeys during local application of dopamine. They found that dopamine increases the gain of sensory-evoked responses in putative pyramidal neurons in PFC, potentially by inhibiting local interneurons. PMID:24401705

  5. The post-occipital spinal venous sinus of the Nile crocodile Crocodylus niloticus: its anatomy and use for blood sample collection and intravenous infusions.

    PubMed

    Myburgh, Jan G; Kirberger, Robert M; Steyl, Johan C A; Soley, John T; Booyse, Dirk G; Huchzermeyer, Fritz W; Lowers, Russel H; Guillette, Louis J

    2014-01-01

    The post-occipital sinus of the spinal vein is often used for the collection of blood samples from crocodilians. Although this sampling method has been reported for several crocodilian species, the technique and associated anatomy has not been described in detail in any crocodilian, including the Nile crocodile (Crocodylus niloticus). The anatomy of the cranial neck region was investigated macroscopically, microscopically, radiographically and by means of computed tomography. Latex was injected into the spinal vein and spinal venous sinus of crocodiles to visualise the regional vasculature. The spinal vein ran within the vertebral canal, dorsal to and closely associated with the spinal cord and changed into a venous sinus cranially in the post-occipital region. For blood collection, the spinal venous sinus was accessed through the interarcuate space between the atlas and axis (C1 and C2) by inserting a needle angled just off the perpendicular in the midline through the craniodorsal cervical skin, just cranial to the cranial borders of the first cervical osteoderms. The most convenient method of blood collection was with a syringe and hypodermic needle. In addition, the suitability of the spinal venous sinus for intravenous injections and infusions in live crocodiles was evaluated. The internal diameter of the commercial human epidural catheters used during these investigations was relatively small, resulting in very slow infusion rates. Care should be taken not to puncture the spinal cord or to lacerate the blood vessel wall using this route for blood collection or intravenous infusions. PMID:24831995

  6. Sound processing hierarchy within human auditory cortex.

    PubMed

    Okamoto, Hidehiko; Stracke, Henning; Bermudez, Patrick; Pantev, Christo

    2011-08-01

    Both attention and masking sounds can alter auditory neural processes and affect auditory signal perception. In the present study, we investigated the complex effects of auditory-focused attention and the signal-to-noise ratio of sound stimuli on three different auditory evoked field components (auditory steady-state response, N1m, and sustained field) by means of magnetoencephalography. The results indicate that the auditory steady-state response originating in primary auditory cortex reflects the signal-to-noise ratio of physical sound inputs (bottom-up process) rather than the listener's attentional state (top-down process), whereas the sustained field, originating in nonprimary auditory cortex, reflects the attentional state rather than the signal-to-noise ratio. The N1m was substantially influenced by both bottom-up and top-down neural processes. The differential sensitivity of the components to bottom-up and top-down neural processes, contingent on their level in the processing pathway, suggests a stream from bottom-up driven sensory neural processing to top-down driven auditory perception within human auditory cortex. PMID:20521859

  7. Functional subregions of the human entorhinal cortex

    PubMed Central

    Maass, Anne; Berron, David; Libby, Laura A; Ranganath, Charan; Düzel, Emrah

    2015-01-01

    The entorhinal cortex (EC) is the primary site of interactions between the neocortex and hippocampus. Studies in rodents and nonhuman primates suggest that EC can be divided into subregions that connect differentially with perirhinal cortex (PRC) vs parahippocampal cortex (PHC) and with hippocampal subfields along the proximo-distal axis. Here, we used high-resolution functional magnetic resonance imaging at 7 Tesla to identify functional subdivisions of the human EC. In two independent datasets, PRC showed preferential intrinsic functional connectivity with anterior-lateral EC and PHC with posterior-medial EC. These EC subregions, in turn, exhibited differential connectivity with proximal and distal subiculum. In contrast, connectivity of PRC and PHC with subiculum followed not only a proximal-distal but also an anterior-posterior gradient. Our data provide the first evidence that the human EC can be divided into functional subdivisions whose functional connectivity closely parallels the known anatomical connectivity patterns of the rodent and nonhuman primate EC. DOI: http://dx.doi.org/10.7554/eLife.06426.001 PMID:26052749

  8. Functional subregions of the human entorhinal cortex.

    PubMed

    Maass, Anne; Berron, David; Libby, Laura; Ranganath, Charan; Düzel, Emrah

    2015-01-01

    The entorhinal cortex (EC) is the primary site of interactions between the neocortex and hippocampus. Studies in rodents and nonhuman primates suggest that EC can be divided into subregions that connect differentially with perirhinal cortex (PRC) vs parahippocampal cortex (PHC) and with hippocampal subfields along the proximo-distal axis. Here, we used high-resolution functional magnetic resonance imaging at 7 Tesla to identify functional subdivisions of the human EC. In two independent datasets, PRC showed preferential intrinsic functional connectivity with anterior-lateral EC and PHC with posterior-medial EC. These EC subregions, in turn, exhibited differential connectivity with proximal and distal subiculum. In contrast, connectivity of PRC and PHC with subiculum followed not only a proximal-distal but also an anterior-posterior gradient. Our data provide the first evidence that the human EC can be divided into functional subdivisions whose functional connectivity closely parallels the known anatomical connectivity patterns of the rodent and nonhuman primate EC. PMID:26052749

  9. The basic nonuniformity of the cerebral cortex

    PubMed Central

    Herculano-Houzel, Suzana; Collins, Christine E.; Wong, Peiyan; Kaas, Jon H.; Lent, Roberto

    2008-01-01

    Evolutionary changes in the size of the cerebral cortex, a columnar structure, often occur through the addition or subtraction of columnar modules with the same number of neurons underneath a unit area of cortical surface. This view is based on the work of Rockel et al. [Rockel AJ, Hiorns RW, Powell TP (1980) The basic uniformity in structure of the neocortex. Brain 103:221–244], who found a steady number of approximately 110 neurons underneath a surface area of 750 ?m2 (147,000 underneath 1 mm2) of the cerebral cortex of five species from different mammalian orders. These results have since been either corroborated or disputed by different groups. Here, we show that the number of neurons underneath 1 mm2 of the cerebral cortical surface of nine primate species and the closely related Tupaia sp. is not constant and varies by three times across species. We found that cortical thickness is not inversely proportional to neuronal density across species and that total cortical surface area increases more slowly than, rather than linearly with, the number of neurons underneath it. The number of neurons beneath a unit area of cortical surface varies linearly with neuronal density, a parameter that is neither related to cortical size nor total number of neurons. Our finding of a variable number of neurons underneath a unit area of the cerebral cortex across primate species indicates that models of cortical organization cannot assume that cortical columns in different primates consist of invariant numbers of neurons. PMID:18689685

  10. On the functional role of temporal and frontal cortex activation in passive detection of auditory deviance

    Microsoft Academic Search

    Chun-Yu Tse; Trevor B. Penney

    2008-01-01

    The superior temporal cortex (STC) and inferior frontal cortex (IFC) are active during pre-attentive change detection. According to one influential model, the temporal cortex is responsible for memory trace comparison and the frontal cortex for attention switching. However, fMRI studies that used parametric designs revealed frontal cortex activity that is inconsistent with this model. In response, alternative accounts of frontal

  11. Gateways of ventral and dorsal streams in mouse visual cortex

    PubMed Central

    Wang, Quanxin; Gao, Enquan; Burkhalter, Andreas

    2011-01-01

    It is widely held that the spatial processing functions underlying rodent navigation are similar to those encoding human episodic memory (Doeller et al, 2010). Spatial and nonspatial information are provided by all senses including vision. It has been suggested that visual inputs are fed to the navigational network in cortex and hippocampus through dorsal and ventral intracortical streams (Whitlock et al, 2008), but this has not been shown directly in rodents. We have used cyto- and chemoarchitectonic markers, topographic mapping of receptive fields and pathway tracing to determine in mouse visual cortex whether the lateromedial (LM) and the anterolateral fields (AL), which are the principal targets of primary visual cortex (V1) (Wang and Burkhalter, 2007) specialized for processing nonspatial and spatial visual information (Gao et al, 2006), are distinct areas with diverse connections. We have found that the LM/AL border coincides with a change in type 2 muscarinic acetylcholine receptor (m2AChR) expression in layer 4 and with the representation of the lower visual field periphery. Our quantitative analyses further show that LM strongly projects to temporal cortex as well as the lateral entorhinal cortex, which has weak spatial selectivity (Hargreaves et al, 2005). In contrast, AL has stronger connections with posterior parietal cortex, motor cortex and the spatially selective medial entorhinal cortex (Haftig et al, 2005). These results support the notion that LM and AL are architecturally, topographically and connectionally distinct areas of extrastriate visual cortex and that they are gateways for ventral and dorsal streams. PMID:21289200

  12. Object decoding with attention in inferior temporal cortex

    E-print Network

    Zhang, Ying

    Recognizing objects in cluttered scenes requires attentional mechanisms to filter out distracting information. Previous studies have found several physiological correlates of attention in visual cortex, including larger ...

  13. Apraxia, pantomime and the parietal cortex

    PubMed Central

    Niessen, E.; Fink, G.R.; Weiss, P.H.

    2014-01-01

    Apraxia, a disorder of higher motor cognition, is a frequent and outcome-relevant sequel of left hemispheric stroke. Deficient pantomiming of object use constitutes a key symptom of apraxia and is assessed when testing for apraxia. To date the neural basis of pantomime remains controversial. We here review the literature and perform a meta-analysis of the relevant structural and functional imaging (fMRI/PET) studies. Based on a systematic literature search, 10 structural and 12 functional imaging studies were selected. Structural lesion studies associated pantomiming deficits with left frontal, parietal and temporal lesions. In contrast, functional imaging studies associate pantomimes with left parietal activations, with or without concurrent frontal or temporal activations. Functional imaging studies that selectively activated parietal cortex adopted the most stringent controls. 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. PMID:24967158

  14. Feature extraction inspired by visual cortex mechanisms

    NASA Astrophysics Data System (ADS)

    Du, Xing; Gong, Weiguo; Li, Weihong

    2010-02-01

    Motivated by the mechanisms of mammalian primary visual cortex (V1), we propose a hierarchical model of feature extraction for object recognition. The proposed model consists of two layers, each of which emulates the functions of V1 simple cells and complex cells respectively. Filters learned from training images are applied at every position of the input image to get an edge feature representation. Then a maximum pooling operation is taken to increase shiftinvariance of the feature. Experiments on face recognition and crop-wise object detection show that our model is competitive with the state-of-the-art biologically-inspired method.

  15. Modeling spatial patterns in the visual cortex

    NASA Astrophysics Data System (ADS)

    Daza C., Yudy Carolina; Tauro, Carolina B.; Tamarit, Francisco A.; Gleiser, Pablo M.

    2014-10-01

    We propose a model for the formation of patterns in the visual cortex. The dynamical units of the model are Kuramoto phase oscillators that interact through a complex network structure embedded in two dimensions. In this way the strength of the interactions takes into account the geographical distance between units. We show that for different parameters, clustered or striped patterns emerge. Using the structure factor as an order parameter we are able to quantitatively characterize these patterns and present a phase diagram. Finally, we show that the model is able to reproduce patterns with cardinal preference, as observed in ferrets.

  16. Ictal Generalized EEG Attenuation (IGEA) and hypopnea in a child with occipital type 1 cortical dysplasia - Is it a biomarker for SUDEP?

    PubMed

    Chaitanya, Ganne; Santosh, N Subbareddy; Velmurugan, Jayabal; Arivazhagan, Arima; Bharath, Rose D; Mahadevan, Anita; Nagappa, Madhu; Bindu, Parayil S; Rao, Malla Bhaskara; Taly, Arun B; Satishchandra, Parthasarathy; Sinha, Sanjib

    2015-01-01

    An interesting association of ictal hypopnea and ictal generalized EEG attenuation (IGEA) as possible marker of sudden unexpected death in epilepsy (SUDEP) is reported. We describe a 5-years-old girl with left focal seizures with secondary generalization due to right occipital cortical dysplasia presenting with ictal hypopnea and IGEA. She had repeated episodes of the ictal apnoea in the past requiring ventilator support and intensive care unit (ICU) admission during episodes of status epilepticus. The IGEA lasted for 0.26-4.68 seconds coinciding with the ictal hypopnea during which both clinical seizure and electrical epileptic activity stopped. Review of literature showed correlation between post-ictal apnoea and post ictal generalized EEG suppression and increased risk for SUDEP. The report adds to the growing body of literature on peri-ictal apnea, about its association with IGEA might be considered as a marker for SUDEP. She is seizure free for 4 months following surgery. PMID:25745325

  17. Fiber tracts connecting mid-fusiform and lateral occipital regions J.M. Davie Yoon, Golijeh Golarai, Bob Dougherty, Michal Ben-Shachar, Alina Liberman, & Kalanit Grill-Spector

    E-print Network

    Grill-Spector, Kalanit

    Fiber tracts connecting mid-fusiform and lateral occipital regions J.M. Davie Yoon, Golijeh Golarai, Poster BB31, Sun 11/16, 3-4pm Introduction Data analysis · Preprocessing: fMRI preprocessing using mr algorithm: conTrack7,8, a probabilistic algorithm that estimates the most likely fiber pathways connecting

  18. Retrosplenial Cortex Codes for Permanent Landmarks

    PubMed Central

    Auger, Stephen D.; Mullally, Sinéad L.; Maguire, Eleanor A.

    2012-01-01

    Landmarks are critical components of our internal representation of the environment, yet their specific properties are rarely studied, and little is known about how they are processed in the brain. Here we characterised a large set of landmarks along a range of features that included size, visual salience, navigational utility, and permanence. When human participants viewed images of these single landmarks during functional magnetic resonance imaging (fMRI), parahippocampal cortex (PHC) and retrosplenial cortex (RSC) were both engaged by landmark features, but in different ways. PHC responded to a range of landmark attributes, while RSC was engaged by only the most permanent landmarks. Furthermore, when participants were divided into good and poor navigators, the latter were significantly less reliable at identifying the most permanent landmarks, and had reduced responses in RSC and anterodorsal thalamus when viewing such landmarks. The RSC has been widely implicated in navigation but its precise role remains uncertain. Our findings suggest that a primary function of the RSC may be to process the most stable features in an environment, and this could be a prerequisite for successful navigation. PMID:22912894

  19. Cognitive Control Signals in Posterior Cingulate Cortex

    PubMed Central

    Hayden, Benjamin Y.; Smith, David V.; Platt, Michael L.

    2010-01-01

    Efficiently shifting between tasks is a central function of cognitive control. The role of the default network – a constellation of areas with high baseline activity that declines during task performance – in cognitive control remains poorly understood. We hypothesized that task switching demands cognitive control to shift the balance of processing toward the external world, and therefore predicted that switching between the two tasks would require suppression of activity of neurons within the posterior cingulate cortex (CGp). To test this idea, we recorded the activity of single neurons in CGp, a central node in the default network, in monkeys performing two interleaved tasks. As predicted, we found that basal levels of neuronal activity were reduced following a switch from one task to another and gradually returned to pre-switch baseline on subsequent trials. We failed to observe these effects in lateral intraparietal cortex, part of the dorsal fronto-parietal cortical attention network directly connected to CGp. These findings indicate that suppression of neuronal activity in CGp facilitates cognitive control, and suggest that activity in the default network reflects processes that directly compete with control processes elsewhere in the brain. PMID:21160560

  20. Representation of numerosity in posterior parietal cortex

    PubMed Central

    Roitman, Jamie D.; Brannon, Elizabeth M.; Platt, Michael L.

    2012-01-01

    Humans and animals appear to share a similar representation of number as an analog magnitude on an internal, subjective scale. Neurological and neurophysiological data suggest that posterior parietal cortex (PPC) is a critical component of the circuits that form the basis of numerical abilities in humans. Patients with parietal lesions are impaired in their ability to access the deep meaning of numbers. Acalculiac patients with inferior parietal damage often have difficulty performing arithmetic (2 + 4?) or number bisection (what is between 3 and 5?) tasks, but are able to recite multiplication tables and read or write numerals. Functional imaging studies of neurologically intact humans performing subtraction, number comparison, and non-verbal magnitude comparison tasks show activity in areas within the intraparietal sulcus (IPS). Taken together, clinical cases and imaging studies support a critical role for parietal cortex in the mental manipulation of numerical quantities. Further, responses of single PPC neurons in non-human primates are sensitive to the numerosity of visual stimuli independent of low-level stimulus qualities. When monkeys are trained to make explicit judgments about the numerical value of such stimuli, PPC neurons encode their cardinal numerical value; without such training PPC neurons appear to encode numerical magnitude in an analog fashion. Here we suggest that the spatial and integrative properties of PPC neurons contribute to their critical role in numerical cognition. PMID:22666194

  1. Mapping the Structural Core of Human Cerebral Cortex

    Microsoft Academic Search

    Patric Hagmann; Leila Cammoun; Xavier Gigandet; Reto Meuli; Christopher J. Honey; Van J. Wedeen; Olaf Sporns

    2008-01-01

    Structurally segregated and functionally specialized regions of the human cerebral cortex are interconnected by a dense network of cortico-cortical axonal pathways. By using diffusion spectrum imaging, we noninvasively mapped these pathways within and across cortical hemispheres in individual human participants. An analysis of the resulting large-scale structural brain networks reveals a structural core within posterior medial and parietal cerebral cortex,

  2. Olfactocentric Paralimbic Cortex Morphology in Adolescents with Bipolar Disorder

    ERIC Educational Resources Information Center

    Wang, Fei; Kalmar, Jessica H.; Womer, Fay Y.; Edmiston, Erin E.; Chepenik, Lara G.; Chen, Rachel; Spencer, Linda; Blumberg, Hilary P.

    2011-01-01

    The olfactocentric paralimbic cortex plays a critical role in the regulation of emotional and neurovegetative functions that are disrupted in core features of bipolar disorder. Adolescence is thought to be a critical period in both the maturation of the olfactocentric paralimbic cortex and in the emergence of bipolar disorder pathology. Together,…

  3. Anatomical Correlates of Functional Plasticity in Mouse Visual Cortex

    Microsoft Academic Search

    Antonella Antonini; Michela Fagiolini; Michael P. Stryker

    1999-01-01

    Much of what is known about activity-dependent plasticity comes from studies of the primary visual cortex and its inputs in higher mammals, but the molecular bases remain largely unknown. Similar functional plasticity takes place during a crit- ical period in the visual cortex of the mouse, an animal in which genetic experiments can readily be performed to investigate the underlying

  4. Modality maps within primate somatosensory cortex Robert M. Friedman*

    E-print Network

    Roe, Anna Wang

    Modality maps within primate somatosensory cortex Robert M. Friedman* , Li Min Chen , and Anna Wang the input stage of primary somatosensory cortex (SI) in primates, area 3b. Little is known about are represented for the other senses is largely unknown. Within each retinotopic domain in area V1, the first

  5. Cerebral Cortex doi:10.1093/cercor/bhr316

    E-print Network

    Kilgard, Michael P.

    Cerebral Cortex doi:10.1093/cercor/bhr316 Repeatedly Pairing Vagus Nerve Stimulation. Repeatedly pairing a tone with a brief period of vagus nerve stimulation (VNS) increases the proportion, motor cortex, motor training, vagus nerve stimulation Introduction Although sensory and motor systems

  6. Distributed coding of sound locations in the auditory cortex

    Microsoft Academic Search

    G. Christopher Stecker; John C. Middlebrooks

    2003-01-01

    Although the auditory cortex plays an impor- tant role in sound localization, that role is not well understood. In this paper, we examine the nature of spatial representation within the auditory cortex, focusing on three questions. First, are sound-source locations encoded by individual sharply tuned neurons or by activity distributed across larger neuronal populations? Second, do temporal features of neural

  7. The Motor Cortex and the Coding of Force

    Microsoft Academic Search

    Apostolos P. Georgopoulos; James Ashe; Nikolaos Smyrnis; Masato Taira

    1992-01-01

    The relation of cellular activity in the motor cortex to the direction of two-dimensional isometric force was investigated under dynamic conditions in monkeys. A task was designed so that three force variables were dissociated: the force exerted by the subject, the net force, and the change in force. Recordings of neuronal activity in the motor cortex revealed that the activity

  8. The human orbitofrontal cortex: linking reward to hedonic experience

    Microsoft Academic Search

    Morten L. Kringelbach

    2005-01-01

    Hedonic experience is arguably at the heart of what makes us human. In recent neuroimaging studies of the cortical networks that mediate hedonic experience in the human brain, the orbitofrontal cortex has emerged as the strongest candidate for linking food and other types of reward to hedonic experience. The orbitofrontal cortex is among the least understood regions of the human

  9. Population Coding of Stimulus Location in Rat Somatosensory Cortex

    Microsoft Academic Search

    Rasmus S. Petersen; Stefano Panzeri; Mathew E. Diamond

    2001-01-01

    This study explores the nature of population coding in sensory cortex by applying information theoretic analyses to neuron pairs recorded simultaneously from rat barrel cortex. We quantified the roles of individual spikes and spike patterns in encoding whisker stimulus location. 82%–85% of the total information was contained in the timing of individual spikes: first spike time was particularly crucial. Spike

  10. Modes of neuronal migration in the developing cerebral cortex

    Microsoft Academic Search

    John G. Parnavelas; Bagirathy Nadarajah

    2002-01-01

    The conventional scheme of cortical formation shows that postmitotic neurons migrate away from the germinal ventricular zone to their positions in the developing cortex, guided by the processes of radial glial cells. However, recent studies indicate that different neuronal types adopt distinct modes of migration in the developing cortex. Here, we review evidence for two modes of radial movement: somal

  11. Activity in Prelimbic Cortex Subserves Fear Memory Reconsolidation over Time

    ERIC Educational Resources Information Center

    Stern, Cristina A. J.; Gazarini, Lucas; Vanvossen, Ana C.; Hames, Mayara S.; Bertoglio, Leandro J.

    2014-01-01

    The prelimbic cortex has been implicated in the consolidation of previously learned fear. Herein, we report that temporarily inactivating this medial prefrontal cortex subregion with the GABA [subscript A] agonist muscimol (4.0 nmol in 0.2 µL per hemisphere) was able to equally disrupt 1-, 7-, and 21-d-old contextual fear memories after their…

  12. Chronic Stress Alters Dendritic Morphology in Rat Medial Prefrontal Cortex

    E-print Network

    Wellman, Cara

    Chronic Stress Alters Dendritic Morphology in Rat Medial Prefrontal Cortex Susan C. Cook,1 Cara L ABSTRACT: Chronic stress produces deficits in cognition accompanied by alterations in neural chemis- try and morphology. Medial prefrontal cortex is a target for glucocorticoids involved in the stress response. We have

  13. Inverse amygdala and medial prefrontal cortex responses to surprised faces

    E-print Network

    Whalen, Paul J.

    Inverse amygdala and medial prefrontal cortex responses to surprised faces Hackjin Kim, Leah H. Somerville, Tom Johnstone, Andrew L. Alexander and Paul J. WhalenCA W.M. Keck Laboratory for Functional BrainMRI activation patterns in amygdala and medial prefrontal cortex (mPFC), depending upon whether subjects

  14. Reduction of orbital frontal cortex volume in geriatric depression

    Microsoft Academic Search

    Te-Jen Lai; Martha E Payne; Christopher E Byrum; David C Steffens; K. Ranga R Krishnan

    2000-01-01

    Background: Postmortem studies have documented abnormalities in the medial orbital frontal cortex in depressed patients. In this study we evaluated whether atrophy of this region can be identified in older depressed patients using magnetic resonance imaging.Methods: Twenty elderly patients meeting DSM-IV criteria for major depression and 20 matched control subjects were studied. The orbital frontal cortex was measured in both

  15. Metaphorically Feeling: Comprehending Textural Metaphors Activates Somatosensory Cortex

    ERIC Educational Resources Information Center

    Lacey, Simon; Stilla, Randall; Sathian, K.

    2012-01-01

    Conceptual metaphor theory suggests that knowledge is structured around metaphorical mappings derived from physical experience. Segregated processing of object properties in sensory cortex allows testing of the hypothesis that metaphor processing recruits activity in domain-specific sensory cortex. Using functional magnetic resonance imaging…

  16. Abnormal Asymmetry in Language Association Cortex in Autism

    E-print Network

    Chabris, Christopher F.

    Abnormal Asymmetry in Language Association Cortex in Autism Martha R. Herbert, MD, PhD,1 Gordon J Masanori Takeoka, MD,7 Helen Tager-Flusberg, PhD,4 and Verne S. Caviness, Jr., MD1 Autism- related cortex in autistic and control subjects. Subjects included 16 boys with autism (aged 7­11 years

  17. The myeloarchitectonic studies on the human cerebral cortex of the Vogt-Vogt school, and their significance for the interpretation of functional neuroimaging data.

    PubMed

    Nieuwenhuys, Rudolf

    2013-03-01

    The human cerebral cortex contains numerous myelinated fibres, many of which are concentrated in tangentially organized layers and radially oriented bundles. The spatial organization of these fibres is by no means homogeneous throughout the cortex. Local differences in the thickness and compactness of the fibre layers, and in the length and strength of the radial bundles renders it possible to recognize areas with a different myeloarchitecture. The neuroanatomical subdiscipline aimed at the identification and delineation of such areas is known as myeloarchitectonics. There is another, closely related neuroanatomical subdiscipline, named cytoarchitectonics. The aims and scope of this subdiscipline are the same as those of myeloarchitectonics, viz. parcellation. However, this subdiscipline focuses, as its name implies, on the size, shape and arrangement of the neuronal cell bodies in the cortex, rather than on the myelinated fibres. At the beginning of the twentieth century, two young investigators, Oskar and Cécile Vogt founded a centre for brain research, aimed to be devoted to the study of the (cyto + myelo) architecture of the cerebral cortex. The study of the cytoarchitecture was entrusted to their collaborator Korbinian Brodmann, who gained great fame with the creation of a cytoarchitectonic map of the human cerebral cortex. Here, we focus on the myeloarchitectonic studies on the cerebral cortex of the Vogt-Vogt school, because these studies are nearly forgotten in the present attempts to localize functional activations and to interprete findings in modern neuroimaging studies. Following introductory sections on the principles of myeloarchitectonics, and on the achievements of three myeloarchitectonic pioneers who did not belong to the Vogt-Vogt school, the pertinent literature is reviewed in some detail. These studies allow the conclusion that the human neocortex contains about 185 myeloarchitectonic areas, 70 frontal, 6 insular, 30 parietal, 19 occipital, and 60 temporal. It is emphasized that the data available, render it possible to compose a myeloarchitectonic map of the human neocortex, which is at least as reliable as any of the classic architectonic maps. During the realization of their myeloarchitectonic research program, in which numerous able collaborators were involved, the Vogts gradually developed a general concept of the organization of the cerebral cortex. The essence of this concept is that this structure is composed of about 200 distinct, juxtaposed 'Rindenfelder' or 'topistische Einheiten', which represent fundamental structural as well as functional entities. The second main part of this article is devoted to a discussion and evaluation of this 'Vogt-Vogt concept'. It is concluded that there is converging quantitative cytoarchitectonic, receptor architectonic, myeloarchitectonic, hodological, and functional evidence, indicating that this concept is essentially correct. The third, and final part of this article deals with the problem of relating particular cortical functions, as determined with neuroimaging techniques, to particular cortical structures. At present, these 'translation' operations are generally based on adapted, three-dimensional versions of Brodmann's famous map. However, it has become increasingly clear that these maps do not provide the neuroanatomical precision to match the considerable degree of functional segregation, suggested by neuroimaging studies. Therefore, we strongly recommend an attempt at combining and synthesizing the results of Brodmann's cytoarchitectonic analysis, with those of the detailed myeloarchitectonic studies of the Vogt-Vogt school. These studies may also be of interest for the interpretation of the myeloarchitectonic features, visualized in modern in vivo mappings of the human cortex. PMID:23076375

  18. Ventromedial prefrontal cortex mediates visual attention during facial emotion recognition

    PubMed Central

    Wolf, Richard C.; Philippi, Carissa L.; Motzkin, Julian C.; Baskaya, Mustafa K.

    2014-01-01

    The ventromedial prefrontal cortex is known to play a crucial role in regulating human social and emotional behaviour, yet the precise mechanisms by which it subserves this broad function remain unclear. Whereas previous neuropsychological studies have largely focused on the role of the ventromedial prefrontal cortex in higher-order deliberative processes related to valuation and decision-making, here we test whether ventromedial prefrontal cortex may also be critical for more basic aspects of orienting attention to socially and emotionally meaningful stimuli. Using eye tracking during a test of facial emotion recognition in a sample of lesion patients, we show that bilateral ventromedial prefrontal cortex damage impairs visual attention to the eye regions of faces, particularly for fearful faces. This finding demonstrates a heretofore unrecognized function of the ventromedial prefrontal cortex—the basic attentional process of controlling eye movements to faces expressing emotion. PMID:24691392

  19. Primary auditory cortex of cats: feature detection or something else?

    PubMed

    Nelken, Israel; Fishbach, Alon; Las, Liora; Ulanovsky, Nachum; Farkas, Dina

    2003-11-01

    Neurons in sensory cortices are often assumed to be "feature detectors", computing simple and then successively more complex features out of the incoming sensory stream. These features are somehow integrated into percepts. Despite many years of research, a convincing candidate for such a feature in primary auditory cortex has not been found. We argue that feature detection is actually a secondary issue in understanding the role of primary auditory cortex. Instead, the major contribution of primary auditory cortex to auditory perception is in processing previously derived features on a number of different timescales. We hypothesize that, as a result, neurons in primary auditory cortex represent sounds in terms of auditory objects rather than in terms of feature maps. According to this hypothesis, primary auditory cortex has a pivotal role in the auditory system in that it generates the representation of auditory objects to which higher auditory centers assign properties such as spatial location, source identity, and meaning. PMID:14669020

  20. Synaptogenesis and dendritic growth in the cortex opposite unilateral sensorimotor cortex damage in adult rats: a quantitative electron microscopic examination

    Microsoft Academic Search

    Theresa A. Jones; Jeffrey A. Kleim; William T. Greenough

    1996-01-01

    Unilateral lesions of the forelimb area of the sensorimotor cortex in adult rats resulted in time-dependent increases in the number of synapses per neuron and the volume and membrane surface area of dendritic processes per neuron within layer V of the contralateral motor cortex in comparison to sham-operated rats. Based on previous findings of a behavioral relationship with increased dendritic

  1. Primary motor cortex isolation: complete paralysis with preserved primary motor cortex

    Microsoft Academic Search

    Katsuyuki Sakai; Emiko Kojima; Masahiko Suzuki; Yoshikazu Ugawa; Yasuo Terao; Ritsuko Hanajima; Ichiro Kanazawa

    1998-01-01

    We present a left-sided hemiplegic patient with a cerebrovascular lesion involving the medial part of the right frontal and parietal lobes and the corpus callosum, but sparing the hand area of right primary motor cortex (M1). Several studies using transcranial magnetic stimulation demonstrated functional integrity of the efferent pathways from the right M1, intact sensory afferents to M1, an impairment

  2. Robust Motion Processing in the Visual Cortex

    NASA Astrophysics Data System (ADS)

    Sederberg, Audrey; Liu, Julia; Kaschube, Matthias

    2009-03-01

    Direction selectivity is an important model system for studying cortical processing. The role of inhibition in models of direction selectivity in the visual cortex is not well understood. We probe the selectivity of an integrate-and-fire neuron with a noisy background on top of a deterministic input current determined by a temporal-lag model for selectivity, including first only excitatory inputs and later both excitatory and inhibitory input. In this model, postsynaptic potentials are fully synchronous for the preferred direction and maximally dispersed in time for the null direction. Further, any inhibitory inputs lag excitatory inputs, as Priebe and Ferster have observed (2005). At any level of input strength, the selectivity is weak when only excitatory inputs are considered. The inclusion of inhibition significantly strengthens selectivity, and this selectivity is preserved over a wide range of background noise levels and for short stimulus durations. We conclude that inhibition likely plays an essential role in the mechanism underlying direction selectivity.

  3. Functional topography of the human entorhinal cortex

    PubMed Central

    Zaragoza Jimenez, Nestor I

    2015-01-01

    Despite extensive research on the role of the rodent medial and lateral entorhinal cortex (MEC/LEC) in spatial navigation, memory and related disease, their human homologues remain elusive. Here, we combine high-field functional magnetic resonance imaging at 7 T with novel data-driven and model-based analyses to identify corresponding subregions in humans based on the well-known global connectivity fingerprints in rodents and sensitivity to spatial and non-spatial information. We provide evidence for a functional division primarily along the anteroposterior axis. Localising the human homologue of the rodent MEC and LEC has important implications for translating studies on the hippocampo-entorhinal memory system from rodents to humans. DOI: http://dx.doi.org/10.7554/eLife.06738.001 PMID:26052748

  4. Functional topography of the human entorhinal cortex.

    PubMed

    Navarro Schröder, Tobias; Haak, Koen V; Zaragoza Jimenez, Nestor I; Beckmann, Christian F; Doeller, Christian F

    2015-01-01

    Despite extensive research on the role of the rodent medial and lateral entorhinal cortex (MEC/LEC) in spatial navigation, memory and related disease, their human homologues remain elusive. Here, we combine high-field functional magnetic resonance imaging at 7 T with novel data-driven and model-based analyses to identify corresponding subregions in humans based on the well-known global connectivity fingerprints in rodents and sensitivity to spatial and non-spatial information. We provide evidence for a functional division primarily along the anteroposterior axis. Localising the human homologue of the rodent MEC and LEC has important implications for translating studies on the hippocampo-entorhinal memory system from rodents to humans. PMID:26052748

  5. Cerebral blood flow modeling in primate cortex

    PubMed Central

    Guibert, Romain; Fonta, Caroline; Plouraboué, Franck

    2010-01-01

    We report new results on blood flow modeling over large volumes of cortical gray matter of primate brain. We propose a network method for computing the blood flow, which handles realistic boundary conditions, complex vessel shapes, and complex nonlinear blood rheology. From a detailed comparison of the available models for the blood flow rheology and the phase separation effect, we are able to derive important new results on the impact of network structure on blood pressure, hematocrit, and flow distributions. Our findings show that the network geometry (vessel shapes and diameters), the boundary conditions associated with the arterial inputs and venous outputs, and the effective viscosity of the blood are essential components in the flow distribution. In contrast, we show that the phase separation effect has a minor function in the global microvascular hemodynamic behavior. The behavior of the pressure, hematocrit, and blood flow distributions within the network are described through the depth of the primate cerebral cortex and are discussed. PMID:20648040

  6. Cerebral blood flow modeling in primate cortex.

    PubMed

    Guibert, Romain; Fonta, Caroline; Plouraboué, Franck

    2010-11-01

    We report new results on blood flow modeling over large volumes of cortical gray matter of primate brain. We propose a network method for computing the blood flow, which handles realistic boundary conditions, complex vessel shapes, and complex nonlinear blood rheology. From a detailed comparison of the available models for the blood flow rheology and the phase separation effect, we are able to derive important new results on the impact of network structure on blood pressure, hematocrit, and flow distributions. Our findings show that the network geometry (vessel shapes and diameters), the boundary conditions associated with the arterial inputs and venous outputs, and the effective viscosity of the blood are essential components in the flow distribution. In contrast, we show that the phase separation effect has a minor function in the global microvascular hemodynamic behavior. The behavior of the pressure, hematocrit, and blood flow distributions within the network are described through the depth of the primate cerebral cortex and are discussed. PMID:20648040

  7. Diffeomorphic Sulcal Shape Analysis on the Cortex

    PubMed Central

    Joshi, Shantanu H.; Cabeen, Ryan P.; Joshi, Anand A.; Sun, Bo; Dinov, Ivo; Narr, Katherine L.; Toga, Arthur W.; Woods, Roger P.

    2014-01-01

    We present a diffeomorphic approach for constructing intrinsic shape atlases of sulci on the human cortex. Sulci are represented as square-root velocity functions of continuous open curves in ?3, and their shapes are studied as functional representations of an infinite-dimensional sphere. This spherical manifold has some advantageous properties – it is equipped with a Riemannian metric on the tangent space and facilitates computational analyses and correspondences between sulcal shapes. Sulcal shape mapping is achieved by computing geodesics in the quotient space of shapes modulo scales, translations, rigid rotations and reparameterizations. The resulting sulcal shape atlas preserves important local geometry inherently present in the sample population. The sulcal shape atlas is integrated in a cortical registration framework and exhibits better geometric matching compared to the conventional euclidean method. We demonstrate experimental results for sulcal shape mapping, cortical surface registration, and sulcal classification for two different surface extraction protocols for separate subject populations. PMID:22328177

  8. Lateral prefrontal cortex contributes to maladaptive decisions

    PubMed Central

    Xue, Gui; Juan, Chi-Hung; Chang, Chi-Fu; Lu, Zhong-Lin; Dong, Qi

    2012-01-01

    Humans consistently make suboptimal decisions involving random events, yet the underlying neural mechanisms remain elusive. Using functional MRI and a matching pennies game that captured subjects’ increasing tendency to predict the break of a streak as it continued [i.e., the “gambler's fallacy” (GF)], we found that a strong blood oxygen level-dependent response in the left lateral prefrontal cortex (LPFC) to the current outcome preceded the use of the GF strategy 10 s later. Furthermore, anodal transcranial direct current stimulation over the left LPFC, which enhances neuronal firing rates and cerebral excitability, increased the use of the GF strategy, and made the decisions more “sticky.” These results reveal a causal role of the LPFC in implementing suboptimal decision strategy guided by false world models, especially when such strategy requires great resources for cognitive control. PMID:22393013

  9. Abnormalities of the foetal cerebral cortex.

    PubMed

    Toi, Ants; Chitayat, David; Blaser, Susan

    2009-04-01

    Prenatal ultrasound has concentrated on readily visible cerebral structures including head size, shape, ventricles, CSP (cavum septi pellucidi), cerebellar size/vermian presence and cisterna magna. However, apart from these easily visible structures it is important to evaluate the brain itself. Patients who initially appear to have mild isolated findings such as borderline ventriculomegaly in fact can have many more subtle findings that significantly alter prognosis and management that can be detected on detailed examination of the brain. There has been rapid evolution in imaging these foetuses, especially with neurosonography and MRI, and a revolution in understanding the underlying genetic and biochemical mechanisms. There is increasing emphasis to detect cortical abnormalities as early as possible. This article reviews development of the cerebral cortex, the classification, aetiologies and clinical manifestations of cortical disorders, normal and abnormal appearances at ultrasound and MRI, and approaches to investigation. PMID:19235759

  10. Evidence for inhibitory deficits in the prefrontal cortex in schizophrenia.

    PubMed

    Radhu, Natasha; Garcia Dominguez, Luis; Farzan, Faranak; Richter, Margaret A; Semeralul, Mawahib O; Chen, Robert; Fitzgerald, Paul B; Daskalakis, Zafiris J

    2015-02-01

    Abnormal gamma-aminobutyric acid inhibitory neurotransmission is a key pathophysiological mechanism underlying schizophrenia. Transcranial magnetic stimulation can be combined with electroencephalography to index long-interval cortical inhibition, a measure of GABAergic receptor-mediated inhibitory neurotransmission from the frontal and motor cortex. In previous studies we have reported that schizophrenia is associated with inhibitory deficits in the dorsolateral prefrontal cortex compared to healthy subjects and patients with bipolar disorder. The main objective of the current study was to replicate and extend these initial findings by evaluating long-interval cortical inhibition from the dorsolateral prefrontal cortex in patients with schizophrenia compared to patients with obsessive-compulsive disorder. A total of 111 participants were assessed: 38 patients with schizophrenia (average age: 35.71 years, 25 males, 13 females), 27 patients with obsessive-compulsive disorder (average age: 36.15 years, 11 males, 16 females) and 46 healthy subjects (average age: 33.63 years, 23 females, 23 males). Long-interval cortical inhibition was measured from the dorsolateral prefrontal cortex and motor cortex through combined transcranial magnetic stimulation and electroencephalography. In the dorsolateral prefrontal cortex, long-interval cortical inhibition was significantly reduced in patients with schizophrenia compared to healthy subjects (P = 0.004) and not significantly different between patients with obsessive-compulsive disorder and healthy subjects (P = 0.5445). Long-interval cortical inhibition deficits in the dorsolateral prefrontal cortex were also significantly greater in patients with schizophrenia compared to patients with obsessive-compulsive disorder (P = 0.0465). There were no significant differences in long-interval cortical inhibition across all three groups in the motor cortex. These results demonstrate that long-interval cortical inhibition deficits in the dorsolateral prefrontal cortex are specific to patients with schizophrenia and are not a generalized deficit that is shared by disorders of severe psychopathology. PMID:25524710

  11. Relationship of ?-aminobutyric acid and glutamate+glutamine concentrations in the perigenual anterior cingulate cortex with performance of Cambridge Gambling Task.

    PubMed

    Fujihara, Kazuyuki; Narita, Kosuke; Suzuki, Yusuke; Takei, Yuichi; Suda, Masashi; Tagawa, Minami; Ujita, Koichi; Sakai, Yuki; Narumoto, Jin; Near, Jamie; Fukuda, Masato

    2015-04-01

    The anterior cingulate cortex (ACC), consisting of the perigenual ACC (pgACC) and mid-ACC (i.e., affective and cognitive areas, respectively), plays a significant role in the performance of gambling tasks, which are used to measure decision-making behavior under conditions of risk. Although recent neuroimaging studies have suggested that the ?-aminobutyric acid (GABA) concentration in the pgACC is associated with decision-making behavior, knowledge regarding the relationship of GABA concentrations in subdivisions of the ACC with gambling task performance is still limited. The aim of our magnetic resonance spectroscopy study is to investigate in 20 healthy males the relationship of concentrations of GABA and glutamate+glutamine (Glx) in the pgACC, mid-ACC, and occipital cortex (OC) with multiple indexes of decision-making behavior under conditions of risk, using the Cambridge Gambling Task (CGT). The GABA/creatine (Cr) ratio in the pgACC negatively correlated with delay aversion score, which corresponds to the impulsivity index. The Glx/Cr ratio in the pgACC negatively correlated with risk adjustment score, which is reported to reflect the ability to change the amount of the bet depending on the probability of winning or losing. The scores of CGT did not significantly correlate with the GABA/Cr or Glx/Cr ratio in the mid-ACC or OC. Results of this study suggest that in the pgACC, but not in the mid-ACC or OC, GABA and Glx concentrations play a distinct role in regulating impulsiveness and risk probability during decision-making behavior under conditions of risk, respectively. PMID:25583607

  12. Medial Frontal Cortex Mediates Perceptual Attentional Set Shifting in the Rat

    Microsoft Academic Search

    Jennifer M. Birrell; Verity J. Brown

    2000-01-01

    If rodents do not display the behavioral complexity that is subserved in primates by prefrontal cortex, then evolution of prefrontal cortex in the rat should be doubted. Primate prefron- tal cortex has been shown to mediate shifts in attention be- tween perceptual dimensions of complex stimuli. This study examined the possibility that medial frontal cortex of the rat is involved

  13. Prefrontal and anterior cingulate cortex abnormalities in Tourette Syndrome: evidence from voxel-based morphometry and magnetization transfer imaging

    PubMed Central

    Müller-Vahl, Kirsten R; Kaufmann, Jörn; Grosskreutz, Julian; Dengler, Reinhard; Emrich, Hinderk M; Peschel, Thomas

    2009-01-01

    Background Pathophysiological evidence suggests an involvement of fronto-striatal circuits in Tourette syndrome (TS). To identify TS related abnormalities in gray and white matter we used optimized voxel-based morphometry (VBM) and magnetization transfer imaging (MTI) which are more sensitive to tissue alterations than conventional MRI and provide a quantitative measure of macrostructural integrity. Methods Volumetric high-resolution anatomical T1-weighted MRI and MTI were acquired in 19 adult, unmedicated male TS patients without co-morbidities and 20 age- and sex-matched controls on a 1.5 Tesla neuro-optimized GE scanner. Images were pre-processed and analyzed using an optimized version of VBM in SPM2. Results Using VBM, TS patients showed significant decreases in gray matter volumes in prefrontal areas, the anterior cingulate gyrus, sensorimotor areas, left caudate nucleus and left postcentral gyrus. Decreases in white matter volumes were detected in the right inferior frontal gyrus, the left superior frontal gyrus and the anterior corpus callosum. Increases were found in the left middle frontal gyrus and left sensorimotor areas. In MTI, white matter reductions were seen in the right medial frontal gyrus, the inferior frontal gyrus bilaterally and the right cingulate gyrus. Tic severity was negatively correlated with orbitofrontal structures, the right cingulate gyrus and parts of the parietal-temporal-occipital association cortex bilaterally. Conclusion Our MRI in vivo neuropathological findings using two sensitive and unbiased techniques support the hypothesis that alterations in frontostriatal circuitries underlie TS pathology. We suggest that anomalous frontal lobe association and projection fiber bundles cause disinhibition of the cingulate gyrus and abnormal basal ganglia function. PMID:19435502

  14. Reduction in glutamine/glutamate levels in the cerebral cortex after adrenocorticotropic hormone therapy in patients with west syndrome.

    PubMed

    Munakata, Mitsutoshi; Togashi, Noriko; Sakamoto, Osamu; Haginoya, Kazuhiro; Kobayashi, Yasuko; Onuma, Akira; Iinuma, Kazuie; Kure, Shigeo

    2014-01-01

    West syndrome (WS), an intractable epileptic encephalopathy of infancy, is refractory to many antiepileptic drugs; however, adrenocorticotropic hormone (ACTH) is an effective treatment for WS. The mechanism behind the efficacy of ACTH is mediated by biochemical processes that remain unknown. We examined the effects of ACTH therapy with tetracosactide (TCS), a synthetic ACTH analogue, on brain metabolism in patients with WS, using (1)H magnetic resonance spectroscopy (¹H-MRS). In six patients with cryptogenic WS, we performed single-voxel ¹H-MRS at the occipital lobe cortex. Measurements were taken prior to TCS treatment, a few days after therapy, and several months after therapy. Data were also compared with subjects having only mild psychomotor delays. The metabolites measured were glutamine plus glutamate (Glx), N-acetylaspartate (NAA), choline (Cho), and myoinositol (mI); each was expressed as a ratio with creatine plus phosphocreatine (total creatine: tCr). The Glx/tCr ratio was significantly reduced after the TCS treatment. The NAA/tCr ratio was also significantly reduced after the treatment compared with the control group, although the change in NAA signal was heterogeneous among patients, correlating with respective outcomes. The Cho/tCr and mI/tCr ratios were not affected by TCS treatment. The reduction in Glx suggests a decrease in the glutamate-glutamine cycle, which plays a pivotal role in synthesizing neurotransmitters such as glutamate and GABA. TCS-induced Glx reduction may induce changes in synaptic signal transduction, thereby accounting for the effect of TCS on WS. The change in NAA indicates altered neuronal activity, which may be correlated with outcome in WS patients. PMID:24705707

  15. A six year retrospective review of occipital nerve stimulation practice - controversies and challenges of an emerging technique for treating refractory headache syndromes

    PubMed Central

    2013-01-01

    Background A retrospective review of patients treated with Occipital Nerve Stimulation (ONS) at two large tertiary referral centres has been audited in order to optimise future treatment pathways. Methods Patient’s medical records were retrospectively reviewed, and each patient was contacted by a trained headache expert to confirm clinical diagnosis and system efficacy. Results were compared to reported outcomes in current literature on ONS for primary headaches. Results Twenty-five patients underwent a trial of ONS between January 2007 and December 2012, and 23 patients went on to have permanent implantation of ONS. All 23 patients reached one-year follow/up, and 14 of them (61%) exceeded two years of follow-up. Seventeen of the 23 had refractory chronic migraine (rCM), and 3 refractory occipital neuralgia (ON). 11 of the 19 rCM patients had been referred with an incorrect headache diagnosis. Nine of the rCM patients (53%) reported 50% or more reduction in headache pain intensity and or frequency at long term follow-up (11–77 months). All 3 ON patients reported more than 50% reduction in pain intensity and/or frequency at 28–31 months. Ten (43%) subjects underwent surgical revision after an average of 11 ± 7 months from permanent implantation - in 90% of cases due to lead problems. Seven patients attended a specifically designed, multi-disciplinary, two-week pre-implant programme and showed improved scores across all measured psychological and functional parameters independent of response to subsequent ONS. Conclusions Our retrospective review: 1) confirms the long-term ONS success rate in refractory chronic headaches, consistent with previously published studies; 2) suggests that some headaches types may respond better to ONS than others (ON vs CM); 3) calls into question the role of trial stimulation in ONS; 4) confirms the high rate of complications related to the equipment not originally designed for ONS; 5) emphasises the need for specialist multidisciplinary care in these patients. PMID:23919570

  16. Cerebrospinal fluid constituents collected at the atlanto-occipital site of xylazine hydrochloride sedated, healthy 8-week-old Holstein calves.

    PubMed Central

    St Jean, G; Yvorchuk-St Jean, K; Anderson, D E; Moore, W E

    1997-01-01

    Cerebrospinal fluid (CSF) collected at the atlanto-occipital site and serum were obtained from 10 male, 8-week-old, Holstein calves after sedation with xylazine hydrochloride. Glucose, creatine kinase, alkaline phosphatase, urea nitrogen, creatinine, sodium, potassium, chloride, calcium, phosphorus, total protein, and albumin were determined in serum and CSF. Optical characteristics, specific gravity, total red blood cell and nucleated cell counts and differentials were also evaluated in the CSF. Additionally, CSF protein electrophoresis and immunoglobulin concentrations were determined. Then, albumin quotients (AQ) were derived. Erythrocytes were observed in 9 of 10 CSF samples. Total nucleated cell counts ranged from 0-10 cells x 10(6)/L with a mean of 3 cells x 10(6)/L. Differential nucleated cell count in the CSF consisted primarily of lymphocytes/small mononuclear cells (57%), fewer monocytes/ large mononuclear cells (38%), and scant neutrophils (4%) and eosinophils (0.05%). The concentration of sodium (134 to 139 mEq/L) was similar to that of serum, but the concentration of potassium (2.8 to 3 mEq/L) was lower than that of serum. Creatine kinase activity (0 to 4 U/L) of CSF was markedly lower than serum activity. The CSF glucose concentration was approximately 80% of the serum value. Cerebrospinal fluid total protein concentration determined by electrophoresis ranged from 110 to 330 mg/L with a mean of 159 mg/L. Cerebrospinal fluid albumin ranged from 48 to 209 mg/L with a mean of 86 mg/L. In all CSF samples, radial immunodiffusion of unaltered CSF and concentrated CSF (four-fold concentration) revealed quantities undetectable by the present techniques in which the lowest standard values for IgG1, IgG, and IgM determinations was 70 mg/L and IgG2 was 30 mg/L. The albumin quotient ranged from 0.15 to 0.65 with a mean of 0.25. Based on the results of this study, CSF may be collected at the atlanto-occipital site safely and efficiently in calves, and reported values for CSF from adult cattle may not be suitable for evaluation of CSF collected from immature cattle. PMID:9114961

  17. Does Retinotopy Influence Cortical Folding in Primate Visual Cortex?

    E-print Network

    Rajimehr, Reza

    In humans and other Old World primates, much of visual cortex comprises a set of retinotopic maps, embedded in a cortical sheet with well known, identifiable folding patterns. However, the relationship between these two ...

  18. Retinotopy versus Face Selectivity in Macaque Visual Cortex

    E-print Network

    Rajimehr, Reza

    Retinotopic organization is a ubiquitous property of lower-tier visual cortical areas in human and nonhuman primates. In macaque visual cortex, the retinotopic maps extend to higher-order areas in the ventral visual pathway, ...

  19. Reorganization of the Human Somatosensory Cortex in Hand Dystonia

    PubMed Central

    Catalan, Maria Jose; Ishii, Kenji; Bara-Jimenez, William; Hallett, Mark

    2012-01-01

    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. PMID:24868405

  20. Cerebral Cortex doi:10.1093/cercor/bhn189

    E-print Network

    Van Essen, David

    of deception. Keywords: anterior cingulate, fMRI, lie detection, lying, neuroimaging, prefrontal cortex magnetic resonance imaging (fMRI) and positron emission tomography (PET) to study deception (Spence et al

  1. NEURAL CODING OF TEMPORAL INFORMATION IN AUDITORY THALAMUS AND CORTEX

    E-print Network

    Wang, Xiaoqin

    Engineering, Johns Hopkins University School of Medicine, 720 Rut- land Avenue, Traylor 410, Baltimore, MD representations of time-vary- ing signals in auditory cortex and thalamus in awake mar- moset monkeys. Findings

  2. Orbitofrontal cortex, decision-making and drug addiction

    PubMed Central

    Schoenbaum, Geoffrey; Roesch, Matthew R.; Stalnaker, Thomas A.

    2008-01-01

    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 expected outcomes to guide decisions. This review will discuss recent evidence that supports this proposal and will examine evidence that loss of this signal, as the result of drug-induced changes in these brain circuits, might account for the maladaptive decision-making that characterizes drug addiction. PMID:16406092

  3. Computerized Mappings of the Cerebral Cortex: A Multiresolution Flattening Method

    E-print Network

    Van Essen, David

    Computerized Mappings of the Cerebral Cortex: A Multiresolution Flattening Method and a Surface for the amount o f distortion introduced. The second stage reduces distortions using a multiresolution strategy

  4. The orbitofrontal cortex in methamphetamine addiction: involvement in fear

    E-print Network

    Goldstein, Rita

    The orbitofrontal cortex in methamphetamine addiction: involvement in fear Rita Z. Goldstein addiction. NeuroReport 13:2253^2257 c 2002 Lippincott Williams & Wilkins. Key words: Constraint superfactor; Drug addiction; Fear; Glucose metabolism; Harm avoidance scale; Inhibitory control; Methamphetamine

  5. CHRYSOTILE ASBESTOS IN KIDNEY CORTEX OF CHRONICALLY GAVAGED RATS

    EPA Science Inventory

    Using the transmission electron microscope, asbestos fibers have been assessed in kidney cortex of four groups of rats previously exposed to intermediate range feeding grade chrysotile asbestos. Newborn rats, from mothers gavaged with asbestos during pregnancy, were gavaged twice...

  6. Reflections on agranular architecture: predictive coding in the motor cortex

    PubMed Central

    Shipp, Stewart; Adams, Rick A.; Friston, Karl J.

    2013-01-01

    The agranular architecture of motor cortex lacks a functional interpretation. Here, we consider a ‘predictive coding’ account of this unique feature based on asymmetries in hierarchical cortical connections. In sensory cortex, layer 4 (the granular layer) is the target of ascending pathways. We theorise that the operation of predictive coding in the motor system (a process termed ‘active inference’) provides a principled rationale for the apparent recession of the ascending pathway in motor cortex. The extension of this theory to interlaminar circuitry also accounts for a sub-class of ‘mirror neuron’ in motor cortex – whose activity is suppressed when observing an action –explaining how predictive coding can gate hierarchical processing to switch between perception and action. PMID:24157198

  7. Descending Projections from the Auditory Cortex to the Inferior

    E-print Network

    Oxford, University of

    Descending Projections from the Auditory Cortex to the Inferior Colliculus in the Gerbil, Meriones unguiculatus VICTORIA M. BAJO* AND DAVID R. MOORE University Laboratory of Physiology, University of Oxford

  8. The spatiotopic 'visual' cortex of the blind

    NASA Astrophysics Data System (ADS)

    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 rules out vision-based explanatory mechanisms, and supports the more radical idea of V1 as a modality-independent 'projection screen' or a 'sketchpad', whose mapping scales to the projective dimensions of objects explored in the peri-personal space.

  9. Wrinkling of a lipid interface induced by actomyosin cortex

    E-print Network

    Hiroaki Ito; Yukinori Nishigami; Seiji Sonobe; Masatoshi Ichikawa

    2015-05-29

    Actomyosin actively generates contractile forces that provide the plasma membrane with the deformation stresses essential to carry out biological processes. Here, we reconstituted a model system with a cell-sized soft interface that exhibits anomalous curvature-radius dependent deformation caused by actomyosin cortex underneath the closed interface, by overcoming the conventional experimental difficulties. The observed curvature dependence was explained by the theoretical description of the cortex elasticity and contractility.

  10. The Evolution of Auditory Cortex: The Core Areas

    Microsoft Academic Search

    Jon H. Kaas

    \\u000a An alternative title might be “What, if Anything, is AI?” AI, of course, is primary auditory cortex, an area of cortex that\\u000a likely all mammals have. Thus, this seems a naive or a puzzling question. Yet, an important issue is hidden in this question.\\u000a And this type of question was formulated long ago: “What, if anything, is a rabbit?” (Wood

  11. Facelift- and circum-occipital incision placement for fat extirpation of the neck in Madelung's disease - a two-case report.

    PubMed

    Hundeshagen, Gregor; Hundeshagen, Gabriel; Assadov, Khamidulla F; Podmelle, Fred

    2014-03-01

    Benign symmetric lipomatosis (Madelung's disease) is a rare disorder of fat metabolism that is characterized by progressive symmetrical formation of unencapsulated and painless excess fat masses around the neck and trunk that result in cosmetic disfiguration and functional impairment. Since the disorder is incompletely understood and causal therapy is unavailable, surgical removal of fatty masses is the mainstay of treatment. In this paper the authors describe their use of the classical facelift incision placement as well as a horizontal circum-occipital incision to approach and excise excess fat of the anterior and posterior neck in two patients. This method yielded satisfying results with a combination of good access to fat masses, smooth trimming and redraping of redundant skin, in addition to fairly inconspicuous scarring post-operatively. After removal of 1.5 kg of fat from each patient and a period of uncomplicated wound healing, both patients showed no signs of relapsing fatty growth. Although more challenging than most conventional approaches, the authors' technique has shown good outcomes in those treated with this condition. PMID:23757287

  12. Brain stem/brain stem occipital bone ratio and the four-line view in nuchal translucency images of fetuses with open spina bifida.

    PubMed

    Iuculano, Ambra; Zoppi, Maria Angelica; Piras, Alessandra; Arras, Maurizio; Monni, Giovanni

    2014-09-10

    Abstract Objective: Brain stem depth/brain stem occipital bone distance (BS/BSOB ratio) and the four-line view, in images obtained for nuchal translucency (NT) screening in fetuses with open spina bifida (OSB). Methods: Single center, retrospective study based on the assessment of NT screening images of fetuses with OSB. A ratio between the BS depth and the BSOB distance was calculated (BS/BSOB ratio) and the four-line view observed, and the sensitivity for a BS/BSOB ratio superior/equal to 1, and for the lack of detection of the four-line view were calculated. Results: There were 17 cases of prenatal diagnosis OSB. In six cases, the suspicion on OSB was raised during NT screening, in six cases, the diagnosis was made before 20 weeks and in five cases during anomaly scan. The BS/BSOB ratio was superior/equal to 1 in all 17 cases, and three lines, were visualized in 15/17 images of the OSB cases, being the sensitivity 100% (95% CI, 81 to 100%) and 88% (95% CI, 65 to 96%). Conclusion: Assessment of BS/BSOB ratio and four-line view in NT images is feasible detecting affected by OSB with high sensitivity. The presence of associated anomalies or of an enlarged NT enhances the early detection. PMID:25123518

  13. Old and new hypotheses about the homology of the compound bones from the cheek and otico-occipital regions of the anuran skull.

    PubMed

    Alcalde, Leandro; Basso, Néstor G

    2013-08-01

    We studied the larval development of compound bones from the otico-occipital and cheek regions in species of the neobatrachian genera Batrachyla, Hylorina, Leptodactylus, Odontophrynus and Pleurodema. Comparisons were made using a set of Ambystoma spp. (Caudata) and Ceratophrys ornata (Anura; Ceratophryidae) larvae. As suggested by previous studies, we verified the compound nature of the exoccipital (two centers, anurans only), frontoparietal (one center, most anurans and Ambystoma; three centers, some anurans), and squamosal (two centers, all anurans and Ambystoma) bones. We discuss old and new homology hypotheses for each of the compound bone centers in the context of the most widely accepted scenario of lissamphibian origins and relationships, i.e., monophyletic Lissamphibia that includes the clade Batrachia (Caudata+Anura) and the most divergent Gymnophiona. Our findings have a direct impact on our understanding of the composition of the skull in Lissamphibia. We recognized the presence of the following bones: (i) opisthotic (fused to the exoccipital) and tabular (fused to the squamosal) in Batrachia (Anura+Caudata) and (ii) supratemporal (fused to the parietal portion of the frontoparietal) in Anura. Separate centers of the parietal were found only in Pleurodema. PMID:23835144

  14. What does spatial alternation tell us about retrosplenial cortex function?

    PubMed Central

    Nelson, Andrew J. D.; Powell, Anna L.; Holmes, Joshua D.; Vann, Seralynne D.; Aggleton, John P.

    2015-01-01

    The retrosplenial cortex supports navigation, but there are good reasons to suppose that the retrosplenial cortex has a very different role in spatial memory from that of the hippocampus and anterior thalamic nuclei. For example, retrosplenial lesions appear to have little or no effect on standard tests of spatial alternation. To examine these differences, the current study sought to determine whether the retrosplenial cortex is important for just one spatial cue type (e.g., allocentric, directional or intra-maze cues) or whether the retrosplenial cortex helps the animal switch between competing spatial strategies or competing cue types. Using T-maze alternation, retrosplenial lesion rats were challenged with situations in which the available spatial information between the sample and test phases was changed, so taxing the interaction between different cue types. Clear lesion deficits emerged when intra- and extra-maze cues were placed in conflict (by rotating the maze between the sample and choice phases), or when the animals were tested in the dark in a double-maze. Finally, temporary inactivation of the retrosplenial cortex by muscimol infusions resulted in a striking deficit on standard T-maze alternation, indicating that, over time, other sites may be able to compensate for the loss of the retrosplenial cortex. This pattern of results is consistent with the impoverished use of both allocentric and directional information, exacerbated by an impaired ability to switch between different cue types. PMID:26042009

  15. Spatial embedding of structural similarity in the cerebral cortex

    PubMed Central

    Song, H. Francis; Kennedy, Henry; Wang, Xiao-Jing

    2014-01-01

    Recent anatomical tracing studies have yielded substantial amounts of data on the areal connectivity underlying distributed processing in cortex, yet the fundamental principles that govern the large-scale organization of cortex remain unknown. Here we show that functional similarity between areas as defined by the pattern of shared inputs or outputs is a key to understanding the areal network of cortex. In particular, we report a systematic relation in the monkey, human, and mouse cortex between the occurrence of connections from one area to another and their similarity distance. This characteristic relation is rooted in the wiring distance dependence of connections in the brain. We introduce a weighted, spatially embedded random network model that robustly gives rise to this structure, as well as many other spatial and topological properties observed in cortex. These include features that were not accounted for in any previous model, such as the wide range of interareal connection weights. Connections in the model emerge from an underlying distribution of spatially embedded axons, thereby integrating the two scales of cortical connectivity—individual axons and interareal pathways—into a common geometric framework. These results provide insights into the origin of large-scale connectivity in cortex and have important implications for theories of cortical organization. PMID:25368200

  16. Neurodynamics of the prefrontal cortex during conditional visuomotor associations.

    PubMed

    Loh, Marco; Pasupathy, Anitha; Miller, Earl K; Deco, Gustavo

    2008-03-01

    The prefrontal cortex is believed to be important for cognitive control, working memory, and learning. It is known to play an important role in the learning and execution of conditional visuomotor associations, a cognitive task in which stimuli have to be associated with actions by trial-and-error learning. In our modeling study, we sought to integrate several hypotheses on the function of the prefrontal cortex using a computational model, and compare the results to experimental data. We constructed a module of prefrontal cortex neurons exposed to two different inputs, which we envision to originate from the inferotemporal cortex and the basal ganglia. We found that working memory properties do not describe the dominant dynamics in the prefrontal cortex, but the activation seems to be transient, probably progressing along a pathway from sensory to motor areas. During the presentation of the cue, the dynamics of the prefrontal cortex is bistable, yielding a distinct activation for correct and error trails. We find that a linear change in network parameters relates to the changes in neural activity in consecutive correct trials during learning, which is important evidence for the underlying learning mechanisms. PMID:18004947

  17. Spatial embedding of structural similarity in the cerebral cortex.

    PubMed

    Song, H Francis; Kennedy, Henry; Wang, Xiao-Jing

    2014-11-18

    Recent anatomical tracing studies have yielded substantial amounts of data on the areal connectivity underlying distributed processing in cortex, yet the fundamental principles that govern the large-scale organization of cortex remain unknown. Here we show that functional similarity between areas as defined by the pattern of shared inputs or outputs is a key to understanding the areal network of cortex. In particular, we report a systematic relation in the monkey, human, and mouse cortex between the occurrence of connections from one area to another and their similarity distance. This characteristic relation is rooted in the wiring distance dependence of connections in the brain. We introduce a weighted, spatially embedded random network model that robustly gives rise to this structure, as well as many other spatial and topological properties observed in cortex. These include features that were not accounted for in any previous model, such as the wide range of interareal connection weights. Connections in the model emerge from an underlying distribution of spatially embedded axons, thereby integrating the two scales of cortical connectivity--individual axons and interareal pathways--into a common geometric framework. These results provide insights into the origin of large-scale connectivity in cortex and have important implications for theories of cortical organization. PMID:25368200

  18. Auditory Cortex Is Required for Fear Potentiation of Gap Detection

    PubMed Central

    Weible, Aldis P.; Liu, Christine; Niell, Cristopher M.

    2014-01-01

    Auditory cortex is necessary for the perceptual detection of brief gaps in noise, but is not necessary for many other auditory tasks such as frequency discrimination, prepulse inhibition of startle responses, or fear conditioning with pure tones. It remains unclear why auditory cortex should be necessary for some auditory tasks but not others. One possibility is that auditory cortex is causally involved in gap detection and other forms of temporal processing in order to associate meaning with temporally structured sounds. This predicts that auditory cortex should be necessary for associating meaning with gaps. To test this prediction, we developed a fear conditioning paradigm for mice based on gap detection. We found that pairing a 10 or 100 ms gap with an aversive stimulus caused a robust enhancement of gap detection measured 6 h later, which we refer to as fear potentiation of gap detection. Optogenetic suppression of auditory cortex during pairing abolished this fear potentiation, indicating that auditory cortex is critically involved in associating temporally structured sounds with emotionally salient events. PMID:25392510

  19. Beta Oscillation Dynamics in Extrastriate Cortex after Removal of Primary Visual Cortex

    PubMed Central

    Schmiedt, Joscha T.; Maier, Alexander; Fries, Pascal; Saunders, Richard C.; Leopold, David A.

    2014-01-01

    The local field potential (LFP) in visual cortex is typically characterized by the following spectral pattern: before the onset of a visual stimulus, low-frequency oscillations (beta, 12–20 Hz) dominate, whereas during the presentation of a stimulus these oscillations diminish and are replaced by fluctuations at higher frequencies (gamma, >30 Hz). The origin of beta oscillations in vivo remains unclear, as is the basis of their suppression during visual stimulation. Here we investigate the contribution of ascending input from primary visual cortex (V1) to beta oscillation dynamics in extrastriate visual area V4 of behaving monkeys. We recorded LFP activity in V4 before and after resecting a portion of V1. After the surgery, the visually induced gamma LFP activity in the lesion projection zone of V4 was markedly reduced, consistent with previously reported spiking responses (Schmid et al., 2013). In the beta LFP range, the lesion had minimal effect on the normal pattern of spontaneous oscillations. However, the lesion led to a surprising and permanent reversal of the normal beta suppression during visual stimulation, with visual stimuli eliciting beta magnitude increases up to 50%, particularly in response to moving stimuli. This reversed beta activity pattern was specific to stimulus locations affected by the V1 lesion. Our results shed light on the mechanisms of beta activity in extrastriate visual cortex: The preserved spontaneous oscillations point to a generation mechanism independent of the geniculostriate pathway, whereas the positive beta responses support the contribution of visual information to V4 via direct thalamo-extrastriate projections. PMID:25164679

  20. Gene Expression Changes in the Prefrontal Cortex, Anterior Cingulate Cortex and Nucleus Accumbens of Mood Disorders Subjects That Committed Suicide

    E-print Network

    2012-01-01

    neurons and astrocytes from rat brain. Chemico-biologicalbrain: extracellular metallothioneins play an important role in the astrocyte-brain specific and expressed mainly in hippocampus amygdala and cortex in zinc enriched neurons and astrocytes [

  1. Does the orbitofrontal cortex signal value?

    PubMed Central

    Schoenbaum, Geoffrey; Takahashi, Yuji; Liu, Tzu-Lan; McDannald, Michael A.

    2012-01-01

    The orbitofrontal cortex (OFC) has long been implicated in associative learning. Early work by Mishkin and Rolls showed that the OFC was critical for rapid changes in learned behavior, a role that was reflected in the encoding of associative information by orbitofrontal neurons. Over the years, new data—particularly neurophysiological data—have increasingly emphasized the OFC in signaling actual value. These signals have been reported to vary according to internal preferences and judgments and to even be completely independent of the sensory qualities of predictive cues, the actual rewards, and the responses required to obtain them. At the same time, increasingly sophisticated behavioral studies have shown that the OFC is often unnecessary for simple value-based behavior and instead seems critical when information about specific outcomes must be used to guide behavior and learning. Here, we review these data and suggest a theory that potentially reconciles these two ideas, value versus specific outcomes, and bodies of work on the OFC. PMID:22145878

  2. Encoding frequency contrast in primate auditory cortex

    PubMed Central

    Scott, Brian H.; Semple, Malcolm N.

    2014-01-01

    Changes in amplitude and frequency jointly determine much of the communicative significance of complex acoustic signals, including human speech. We have previously described responses of neurons in the core auditory cortex of awake rhesus macaques to sinusoidal amplitude modulation (SAM) signals. Here we report a complementary study of sinusoidal frequency modulation (SFM) in the same neurons. Responses to SFM were analogous to SAM responses in that changes in multiple parameters defining SFM stimuli (e.g., modulation frequency, modulation depth, carrier frequency) were robustly encoded in the temporal dynamics of the spike trains. For example, changes in the carrier frequency produced highly reproducible changes in shapes of the modulation period histogram, consistent with the notion that the instantaneous probability of discharge mirrors the moment-by-moment spectrum at low modulation rates. The upper limit for phase locking was similar across SAM and SFM within neurons, suggesting shared biophysical constraints on temporal processing. Using spike train classification methods, we found that neural thresholds for modulation depth discrimination are typically far lower than would be predicted from frequency tuning to static tones. This “dynamic hyperacuity” suggests a substantial central enhancement of the neural representation of frequency changes relative to the auditory periphery. Spike timing information was superior to average rate information when discriminating among SFM signals, and even when discriminating among static tones varying in frequency. This finding held even when differences in total spike count across stimuli were normalized, indicating both the primacy and generality of temporal response dynamics in cortical auditory processing. PMID:24598525

  3. Gustatory cortex of primates: anatomy and physiology.

    PubMed

    Ogawa, H

    1994-07-01

    Clinical and physiological studies of patients with ageusia or gustatory hallucination suggest that the primary gustatory area (area G) lies at the anterior insula or at the base of the central sulcus. However, physiological and anatomical studies in subhuman primates, e.g. squirrel monkeys or macaque monkeys, locate area G at the buried frontal operculum (Fop) and dorsal insula. The presence of secondary or higher gustatory areas are claimed because taste neurons are found in the precentral opercular area (PrCO) or orbitofrontal cortex in alert monkeys. Part of the anterior insula is suggested to subserve the interface between area G and the amygdala. Many physiological studies have been conducted lacking knowledge of the histological boundaries of the primary and secondary gustatory areas. Some difference has been found in the physiological properties of taste neurons in the primary and secondary gustatory areas: the primary gustatory area contains various categories of taste neurons, whereas most of the taste neurons in the secondary gustatory areas (e.g., PrCO, area 1-2) are specifically sensitive to one of the four basic tastes, and taste neurons in the orbitofrontal opercular area (OFO), another secondary gustatory area, show sensory-specific hunger as well. PMID:7984335

  4. Decision Salience Signals in Posterior Cingulate Cortex

    PubMed Central

    Heilbronner, Sarah R.; Hayden, Benjamin Y.; Platt, Michael L.

    2011-01-01

    Despite its phylogenetic antiquity and clinical importance, the posterior cingulate cortex (CGp) remains an enigmatic nexus of attention, memory, motivation, and decision making. Here we show that CGp neurons track decision salience – the degree to which an option differs from a standard – but not the subjective value of a decision. To do this, we recorded the spiking activity of CGp neurons in monkeys choosing between options varying in reward-related risk, delay to reward, and social outcomes, each of which varied in level of decision salience. Firing rates were higher when monkeys chose the risky option, consistent with their risk-seeking preferences, but were also higher when monkeys chose the delayed and social options, contradicting their preferences. Thus, across decision contexts, neuronal activity was uncorrelated with how much monkeys valued a given option, as inferred from choice. Instead, neuronal activity signaled the deviation of the chosen option from the standard, independently of how it differed. The observed decision salience signals suggest a role for CGp in the flexible allocation of neural resources to motivationally significant information, akin to the role of attention in selective processing of sensory inputs. PMID:21541308

  5. Deep brain and motor cortex stimulation.

    PubMed

    Sukul, Vishad V; Slavin, Konstantin V

    2014-07-01

    Deep brain stimulation (DBS) and motor cortex stimulation (MCS) are established surgical modalities that have been successfully used over the last several decades for treatment of numerous chronic pain disorders. Most often, these approaches are reserved for severe, disabling, and medically refractory syndromes after less invasive approaches have been tried and have failed. Although the exact mechanism of action for DBS and MCS remains unknown, it appears that these central neuromodulation processes have multifactorial effects on central pain processing and descending pain inhibition. Clinical studies and laboratory reports have shed some light on stimulation details and optimal parameters, as well as the choice of stimulation targets, best surgical indications, and expected long-term outcomes. Based on the worldwide published experience, it appears that additional data is needed to obtain regulatory approval for both MCS and DBS for the treatment of pain. Following approval, further clinical research will shape the ability to initiate, implement, and update comprehensive patient and procedure selection paradigms. PMID:24817154

  6. Neural discriminability in rat lateral extrastriate cortex and deep but not superficial primary visual cortex correlates with shape discriminability

    PubMed Central

    Vermaercke, Ben; Van den Bergh, Gert; Gerich, Florian; Op de Beeck, Hans

    2015-01-01

    Recent studies have revealed a surprising degree of functional specialization in rodent visual cortex. It is unknown to what degree this functional organization is related to the well-known hierarchical organization of the visual system in primates. We designed a study in rats that targets one of the hallmarks of the hierarchical object vision pathway in primates: selectivity for behaviorally relevant dimensions. We compared behavioral performance in a visual water maze with neural discriminability in five visual cortical areas. We tested behavioral discrimination in two independent batches of six rats using six pairs of shapes used previously to probe shape selectivity in monkey cortex (Lehky and Sereno, 2007). The relative difficulty (error rate) of shape pairs was strongly correlated between the two batches, indicating that some shape pairs were more difficult to discriminate than others. Then, we recorded in naive rats from five visual areas from primary visual cortex (V1) over areas LM, LI, LL, up to lateral occipito-temporal cortex (TO). Shape selectivity in the upper layers of V1, where the information enters cortex, correlated mostly with physical stimulus dissimilarity and not with behavioral performance. In contrast, neural discriminability in lower layers of all areas was strongly correlated with behavioral performance. These findings, in combination with the results from Vermaercke et al. (2014b), suggest that the functional specialization in rodent lateral visual cortex reflects a processing hierarchy resulting in the emergence of complex selectivity that is related to behaviorally relevant stimulus differences. PMID:26041999

  7. Transient topographical amnesia and cingulate cortex damage: a case report.

    PubMed

    Cammalleri, R; Gangitano, M; D'Amelio, M; Raieli, V; Raimondo, D; Camarda, R

    1996-04-01

    Transient topographical amnesia (TTA) is the temporary inability to find one's way in familiar or unfamiliar surroundings due to the inability to use well known environmental landmarks for route finding. The syndrome has not been described as having any obvious aetiology and has been thought to be caused by a vascular deficit in right hemispheric structures which are crucial for topographic recognition, i.e. parietal association and parahippocampal cortex. The patient described in the present study complained of several critical episodes of TTA and tonic rigidity of the left limbs. Neuropsychological assessment was normal except for a deficit in spatial memory tasks. Magnetic resonance (MR) imaging of the brain showed an angioma at the border of areas 24d and 23 of the right cingulate cortex. Because area 23 is strategically located in a network that links the parietal associative (area 7a) and parahippocampal cortices, and because these cortical areas are involved in topographical orienting processes, we suggest that a transient functional inactivation of the network caused by epileptic discharges spreading from the damaged cingulate cortex towards the parahippocampal and parietal association cortex could account for the spatial disorder. Similar discharges spreading from area 24d towards the primary motor cortex and/or the spinal cord could account for the episodes of tonic rigidity of the left limbs. PMID:8657363

  8. The Interplay between Estrogen and Fetal Adrenal Cortex

    PubMed Central

    Kaludjerovic, Jovana; Ward, Wendy E.

    2012-01-01

    Estrogen is a steroid hormone that regulates embryogenesis, cell proliferation and differentiation, organogenesis, the timing of parturition, and fetal imprinting by carrying chemical messages from glands to cells within tissues or organs in the body. During development, placenta is the primary source of estrogen production but estrogen can only be produced if the fetus or the mother supplies dehydroepiandrosterone (DHEA), the estrogen prohormone. Studies show that the fetal zone of the fetal adrenal cortex supplies 60% of DHEA for placental estrogen production, and that placental estrogen in turn modulates the morphological and functional development of the fetal adrenal cortex. As such, in developed countries where humans are exposed daily to environmental estrogens, there is concern that the development of fetal adrenal cortex, and in turn, placental estrogen production may be disrupted. This paper discusses fetal adrenal gland development, how endogenous estrogen regulates the structure and function of the fetal adrenal cortex, and highlights the potential role that early life exposure to environmental estrogens may have on the development and endocrinology of the fetal adrenal cortex. PMID:22536492

  9. Recovery of function following unilateral damage to visuoparietal cortex.

    PubMed

    Rushmore, R J; Payne, Bertram; Valero-Cabre, Antoni

    2010-06-01

    Damage to the visuoparietal cortex located in the banks of the middle suprasylvian gyrus of the cat has been shown to produce a deficit in the detection and localization of moving visual cues presented in the contralesional visual hemifield. There is evidence from reversible cooling deactivation studies that the integrity of this orienting function is not completely dependent on the VP cortex and that under the right circumstances, other brain regions may come online and completely take over the processing that subserves this behavior. We examined the recovery of orienting behavior after unilateral damage to the VP cortex. We found that consistent with previous data, VP damage produced an impairment in the capacity to detect and orient to moving visual stimuli in the contralesional visual field. Over a span of days, spontaneous recovery fully occurred. The ability to detect and localize static visual stimuli was tested as a fiducial measure of parietal cortex function, and this function did not recover. We conclude that the detection and localization of moving visual stimuli is not a function that requires VP cortex and argue for the existence of a parallel and redundant subcortical-cortical brain network that serves as the substrate for recovery of function. PMID:20461362

  10. Adrenal cortex tissue homeostasis and zonation: A WNT perspective.

    PubMed

    Drelon, Coralie; Berthon, Annabel; Mathieu, Mickael; Martinez, Antoine; Val, Pierre

    2015-06-15

    The adrenal cortex plays essential roles in the control of sodium and water homeostasis, stress response, inflammation and metabolism, through secretion of glucocorticoids and mineralocorticoids. Coordinated production of these hormones relies on functional zonation of the cortex, characterised by expression of Cyp11b2 under the control of angiotensin II and plasma potassium level in zona glomerulosa (ZG) and Cyp11b1 under the control of ACTH in zona fasciculata (ZF). The mechanisms involved in the establishment of functional zonation and its maintenance during centripetal cortex cell renewal are still poorly understood. Here, we hypothesise that the hormonal and signalling pathways that control adrenal cortex function are also involved in cortical zonation. In particular, we summarise evidence on the role of WNT/?-catenin signalling in ZG differentiation and how tight control of its activity is required to shape the adult cortex. In this context, we discuss the potential role of known WNT regulators and the possibility of a reciprocal cross-talk between PKA and WNT signalling. PMID:25542843

  11. Cultivating the cortex in German neuroanatomy.

    PubMed

    Hagner, M

    2001-12-01

    The cerebral localization of mental functions is one of the centerpieces of modern brain research. Though the localization paradigm in its cultural and social interwovenness has been characterized as successful in the last third of the nineteenth century by a variety of historians of the neurosciences, there is also general agreement that localization came under threat around 1900. Besides the so-called holistic protest against the localization of mental functions, the neuroanatomical approach itself was challenged by experimental psychology, psychiatric nosology, and psychoanalysis. This story underestimates the fact that anatomically-based localization remained powerful in response to these multiple challenges. This meant a neuroanatomical revision of tools, concepts, and practices. But this meant also a shift in the cultivation of the cortex from a more philosophical agenda to rather concrete political claims. More specifically, the idea of the cortext as the noblest part of man was supplemented by suggestions concerning its "Höherzüchtung." I will analyze this re-orientation and radicalization in two steps. First, I briefly discuss the anatomical and philosophical account of Theodor Meynert and then turn to Paul Flechsig who in the late nineteenth century inscribed the ability to create culture and civilization into the cortext. Second, I focus on the neuroanatomists Oskar and Cécile Vogt, who began their careers around 1900 and expanded the cultivation of the cortext. Even before World War I, they proclaimed a "cerebral hygiene." Consequently, the Vogts linked their innovative neuroanatomical researches with the rising field of genetics, racial hygiene, and eugenics. In the early Weimar Republic, the Vogts openly supported socialist ideas and were engaged in establishing an Institute for Brain Research in Soviet Moscow, where Lenin's brain was analyzed. By the end of the Weimar Republic, the rhetoric of the Vogts was bluntly authoritarian. Based on a few anatomical examinations of so-called elite brains and the brains of criminals, they made concrete suggestions for eugenics and the breeding of "one-sidedly gifted leaders." Given the remarkable popularity of the Vogts around 1930, their program is an important example of the hubris of predicting and guiding future developments on the basis of scientific authority. It can be regarded as an ironic nemesis that the Vogts - never sympathizing with the political aims of the National Socialists - were forced to finish their careers as influential Kaiser Wilhelm scientists in Nazi-Germany. PMID:12174862

  12. A cholinergic mechanism for reward timing within primary visual cortex.

    PubMed

    Chubykin, Alexander A; Roach, Emma B; Bear, Mark F; Shuler, Marshall G Hussain

    2013-02-20

    Neurons in rodent primary visual cortex (V1) relate operantly conditioned stimulus-reward intervals with modulated patterns of spiking output, but little is known about the locus or mechanism of this plasticity. Here we show that cholinergic basal forebrain projections to V1 are necessary for the neural acquisition, but not the expression, of reward timing in the visual cortex of awake, behaving animals. We then mimic reward timing in vitro by pairing white matter stimulation with muscarinic receptor activation at a fixed interval and show that this protocol results in the prolongation of electrically evoked spike train durations out to the conditioned interval. Together, these data suggest that V1 possesses the circuitry and plasticity to support reward time prediction learning and the cholinergic system serves as an important reinforcement signal which, in vivo, conveys to the cortex the outcome of behavior. PMID:23439124

  13. A cholinergic mechanism for reward timing within primary visual cortex

    PubMed Central

    Chubykin, Alexander A.; Roach, Emma B.; Bear, Mark F.; Shuler, Marshall G. Hussain

    2013-01-01

    Summary Neurons in rodent primary visual cortex (V1) relate operantly conditioned stimulus-reward intervals with modulated patterns of spiking output, but little is known about the locus or mechanism of this plasticity. Here we show that cholinergic basal forebrain projections to V1 are necessary for the neural acquisition, but not the expression, of reward timing in the visual cortex of awake, behaving animals. We then mimic reward timing in vitro by pairing white matter stimulation with muscarinic receptor activation at a fixed interval, and show that this protocol results in the prolongation of electrically-evoked spike train durations out to the conditioned interval. Together, these data suggest that (1) V1 possesses the circuitry and plasticity to support reward time prediction learning and (2) the cholinergic system serves as an important reinforcement signal which, in vivo, conveys to the cortex the outcome of behavior. PMID:23439124

  14. Associative Hebbian Synaptic Plasticity in Primate Visual Cortex

    PubMed Central

    Huang, Shiyong; Rozas, Carlos; Treviño, Mario; Contreras, Jessica; Yang, Sunggu; Song, Lihua; Yoshioka, Takashi; Lee, Hey-Kyoung

    2014-01-01

    In primates, the functional connectivity of adult primary visual cortex is susceptible to be modified by sensory training during perceptual learning. It is widely held that this type of neural plasticity might involve mechanisms like long-term potentiation (LTP) and long-term depression (LTD). NMDAR-dependent forms of LTP and LTD are particularly attractive because in rodents they can be induced in a Hebbian manner by near coincidental presynaptic and postsynaptic firing, in a paradigm termed spike timing-dependent plasticity (STDP). These fundamental properties of LTP and LTD, Hebbian induction and NMDAR dependence, have not been examined in primate cortex. Here we demonstrate these properties in the primary visual cortex of the rhesus macaque (Macaca mulatta), and also show that, like in rodents, STDP is gated by neuromodulators. These findings indicate that the cellular principles governing cortical plasticity are conserved across mammalian species, further validating the use of rodents as a model system. PMID:24872561

  15. Interplay of hippocampus and prefrontal cortex in memory

    PubMed Central

    Preston, Alison R.; Eichenbaum, Howard

    2013-01-01

    Recent studies on the hippocampus and the prefrontal cortex have considerably advanced our understanding of the distinct roles of these brain areas in the encoding and retrieval of memories, and of how they interact in the prolonged process by which new memories are consolidated into our permanent storehouse of knowledge. These studies have led to a new model of how the hippocampus forms and replays memories and how the prefrontal cortex engages representations of the meaningful contexts in which related memories occur, as well as how these areas interact during memory retrieval. Furthermore, they have provided new insights into how interactions between the hippocampus and prefrontal cortex support the assimilation of new memories into pre-existing networks of knowledge, called schemas, and how schemas are modified in this process as the foundation of memory consolidation. PMID:24028960

  16. The role of the actin cortex in maintaining cell shape

    PubMed Central

    Haase, Kristina; Pelling, Andrew E

    2013-01-01

    Considering that the plasma membrane is host to a variety of mechanical cues in vivo, and the actin cortex is known to support cell shape, it comes as no surprise that the paired membrane-cortex plays a major role in cellular responses to deformation. In a recent study, we applied highly localized forces to HeLa cells in order to examine the deformation response of the membrane and cortex. Direct visualization of the deformation in the loading plane allowed for the characterization of the observed time-dependent strain. Despite large magnitude and long duration loading regimes, the majority of cells recovered their initial pre-deformed morphology within ~2 min. Unexpectedly, perturbed regions above large-volume nuclei were shown to be quite soft and had negligible influence on morphological recovery. The resistance to deformation and ability to recover was found to be largely influenced by the actin network, and dependent upon rho-kinase mediated contractility. PMID:24349607

  17. Evidence for Pitch Chroma Mapping in Human Auditory Cortex

    PubMed Central

    Briley, Paul M.; Breakey, Charlotte; Krumbholz, Katrin

    2013-01-01

    Some areas in auditory cortex respond preferentially to sounds that elicit pitch, such as musical sounds or voiced speech. This study used human electroencephalography (EEG) with an adaptation paradigm to investigate how pitch is represented within these areas and, in particular, whether the representation reflects the physical or perceptual dimensions of pitch. Physically, pitch corresponds to a single monotonic dimension: the repetition rate of the stimulus waveform. Perceptually, however, pitch has to be described with 2 dimensions, a monotonic, “pitch height,” and a cyclical, “pitch chroma,” dimension, to account for the similarity of the cycle of notes (c, d, e, etc.) across different octaves. The EEG adaptation effect mirrored the cyclicality of the pitch chroma dimension, suggesting that auditory cortex contains a representation of pitch chroma. Source analysis indicated that the centroid of this pitch chroma representation lies somewhat anterior and lateral to primary auditory cortex. PMID:22918980

  18. Multiple sensory afferents to ferret pseudosylvian sulcal cortex.

    PubMed

    Ramsay, Abigail M; Meredith, M Alex

    2004-03-01

    While the ferret cerebral cortex is being used with increasing frequency in studies of neural processing and development, little is known regarding the organization of its associational sensory and multisensory regions. Therefore, the present investigation used neuroanatomical methods to identify non-primary visual and somatosensory representations and their potential for multisensory convergence. Tracer injections made into V1 or SI cortex labeled axon terminals within the pseudosylvian sulcal cortex (PSSC). These inputs were distributed according to modality, with visual inputs identified in the lateral aspects of the posterior dorsal bank, and somatosensory inputs found anterior along the dorsal bank, fundus and ventral bank. Somatosensory inputs showed a topographic arrangement, with inputs representing face found more anteriorly than those representing trunk regions. Overlap between these different sensory projections occurred posteriorly in the PSSC and may represent a zone of multisensory convergence. These data are consistent with the presence of associational visual, somatosensory, and multisensory areas within the PSSC. PMID:15094504

  19. Cortical Connections of Functional Zones in Posterior Parietal Cortex and Frontal Cortex Motor Regions in New World Monkeys

    PubMed Central

    Stepniewska, Iwona; Kaas, Jon H.

    2011-01-01

    We examined the connections of posterior parietal cortex (PPC) with motor/premotor cortex (M1/PM) and other cortical areas. Electrical stimulation (500 ms trains) delivered to microelectrode sites evoked movements of reach, defense, and grasp, from distinct zones in M1/PM and PPC, in squirrel and owl monkeys. Tracer injections into M1/PM reach, defense, and grasp zones showed dense connections with M1/PM hand/forelimb representations. The densest inputs outside of frontal cortex were from PPC zones. M1 zones were additionally connected with somatosensory hand/forelimb representations in areas 3a, 3b, and 1 and the somatosensory areas of the upper bank of the lateral sulcus (S2/PV). Injections into PPC zones showed primarily local connections and the densest inputs outside of PPC originated from M1/PM zones. The PPC reach zone also received dense inputs from cortex caudal to PPC, which likely relayed visual information. In contrast, the PPC grasp zone was densely connected with the hand/forelimb representations of areas 3a, 3b, 1, and S2/PV. Thus, the dorsal parietal–frontal network involved in reaching was preferentially connected to visual cortex, whereas the more ventral network involved in grasping received somatosensory inputs. Additional weak interlinks between dissimilar zones (e.g., PPC reach and PPC grasp) were apparent and may coordinate actions. PMID:21263034

  20. PSA-NCAM expression in the rat medial prefrontal cortex.

    PubMed

    Varea, E; Nácher, J; Blasco-Ibáñez, J M; Gómez-Climent, M A; Castillo-Gómez, E; Crespo, C; Martínez-Guijarro, F J

    2005-01-01

    The rat medial prefrontal cortex, an area considered homologous to the human prefrontal cortex, is a region in which neuronal structural plasticity has been described during adulthood. Some plastic processes such as neurite outgrowth and synaptogenesis are known to be regulated by the polysialylated form of the neural cell adhesion molecule (PSA-NCAM). Since PSA-NCAM is present in regions of the adult CNS which are undergoing structural remodeling, such as the hypothalamus or the hippocampus, we have analyzed the expression of this molecule in the medial prefrontal cortex of adult rats using immunohistochemistry. PSA-NCAM immunoreactivity was found both in cell bodies and in the neuropil of the three divisions of the medial prefrontal cortex. All cell somata expressing PSA-NCAM corresponded to neurons and 5' bromodeoxyuridine labeling after long survival times demonstrated that these neurons were not recently generated. Many of these PSA-NCAM immunoreactive neurons in the medial prefrontal cortex could be classified as interneurons on the basis of their morphology and glutamate decarboxylase, isoform 67 expression. Some of the PSA-NCAM immunoreactive neurons also expressed somatostatin, neuropeptide Y and calbindin-D28K. By contrast, pyramidal neurons in this cortical region did not appear to express PSA-NCAM. However, some of these principal neurons appeared surrounded by PSA-NCAM immunoreactive puncta. Some of these puncta co-expressed synaptophysin, suggesting the presence of synapses. Since the etiology of some psychiatric disorders has been related to alterations in medial prefrontal cortex structural plasticity, the study of PSA-NCAM expression in this region may open a new approach to the pathophysiology of these mental disorders. PMID:16216431

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

    PubMed

    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. PMID:21807616

  2. Antidepressant action of HDAC inhibition in the prefrontal cortex.

    PubMed

    Covington, H E; Maze, I; Vialou, V; Nestler, E J

    2015-07-01

    Previous research has demonstrated antidepressant-like effects in rodents upon intracerebral inhibition of histone deacetylases (HDACs). Such effects have been reported for local HDAC inhibition in the nucleus accumbens, hippocampus, and amygdala. However, the effect of HDAC inhibition within the medial prefrontal cortex, which is integral to depression-related symptoms and their treatment, remains unknown. Here we show that local infusion of the highly selective HDAC inhibitor, MS-275, into the medial prefrontal cortex exerts robust antidepressant-like effects in the chronic social defeat stress paradigm in mice. These findings provide further impetus for the assessment of HDAC inhibitors for the treatment of depression. PMID:25907440

  3. Bilateral activity and callosal connections in the somatosensory cortex.

    PubMed

    Iwamura, Y; Taoka, M; Iriki, A

    2001-10-01

    Earlier studies recording single neuronal activity in the postcentral somatosensory cortex of monkeys converged in suggesting that the bilateral receptive fields were related exclusively to the body midline including the trunk, perioral face, and oral cavity. These neurons were recorded mostly in the rostral part of the gyrus, areas 3b and 1. However, the authors recently found a substantial number of neurons with bilateral receptive fields on extremities, hand/digits, shoulders/arms, or legs/feet in the caudalmost part (areas 2 and 5) of the postcentral gyrus. The authors review these results and discuss functional implications of the bilateral representation in the postcentral somatosensory cortex. PMID:11597101

  4. Long-term motor cortex stimulation for phantom limb pain.

    PubMed

    Pereira, Erlick A C; Moore, Tom; Moir, Liz; Aziz, Tipu Z

    2015-04-01

    We present the long-term course of motor cortex stimulation to relieve a case of severe burning phantom arm pain after brachial plexus injury and amputation. During 16-year follow-up the device continued to provide efficacious analgesia. However, several adjustments of stimulation parameters were required, as were multiple pulse generator changes, antibiotics for infection and one electrode revision due to lead migration. Steady increases in stimulation parameters over time were required. One of the longest follow-ups of motor cortex stimulation is described; the case illustrates challenges and pitfalls in neuromodulation for chronic pain, demonstrating strategies for maintaining analgesia and overcoming tolerance. PMID:25340991

  5. Effect of Undercutting on the Acetylcholinesterase and Choline Acetyltransferase Activity in the Cat's Cerebral Cortex

    Microsoft Academic Search

    Catherine O. Hebb; K. Krnjevic; Ann Silver

    1963-01-01

    IT has been shown that the mammalian cerebral cortex contains a substantial amount of acetylcholinesterase1,2 and choline acetyltransferase3,4. Moreover, large quantities of acetylcholine are released from the cortex5,6.

  6. What are the Computations of the Cerebellum, the Basal Gangila, and the Cerebral Cortex?

    E-print Network

    Doya, Kenji

    ganglia participate in 2 #12;Cerebral Cortex Basal Ganglia Cerebellum Thalamus substantia nigra inferior olive Figure 1: Global network linking the cerebellum, the basal ganglia, and the cerebral cortex

  7. Individual Differences in Amygdala and Ventromedial Prefrontal Cortex Activity are Associated with

    E-print Network

    Wisconsin at Madison, University of

    Individual Differences in Amygdala and Ventromedial Prefrontal Cortex Activity are Associated differences in amygdala activation in re- sponse to negative relative to neutral information are related information were associated with increased left and right amygdala activation. In the prefrontal cortex

  8. Reduction of human visual cortex excitability using 1-Hz transcranial magnetic stimulation.

    PubMed

    Boroojerdi, B; Prager, A; Muellbacher, W; Cohen, L G

    2000-04-11

    The effects of low-frequency (1-Hz) repetitive transcranial magnetic stimulation on visual cortex excitability were investigated by measuring phosphene thresholds (PTs) and stimulus-response curves. Stimulation over the visual cortex led to significantly decreased visual cortex excitability, expressed as an increase in PT. The motor threshold of the hand muscles did not change, indicating the topographic specificity of this effect. This intervention may be useful in situations associated with a hyperexcitable visual cortex. PMID:10751273

  9. Corticostriatal projections from the somatic motor areas of the frontal cortex in the macaque monkey: segregation versus overlap of input zones from the primary motor cortex, the supplementary motor area, and the premotor cortex

    Microsoft Academic Search

    M. Takada; H. Tokuno; A. Nambu; M. Inase

    1998-01-01

    It is an important issue to address the mode of information processing in the somatic motor circuit linking the frontal cortex\\u000a and the basal ganglia. In the present study, we investigated the extent to which corticostriatal input zones from the primary\\u000a motor cortex (MI), the supplementary motor area (SMA), and the premotor cortex (PM) of the macaque monkey might overlap

  10. [A clinical study of the number processing system: decimal size effects on reading numbers in patients with left parieto-occipital gliomas].

    PubMed

    Gasparini, F M; Cohen, L; Lopes, M; Denvil, D; Capelle, L; Duffau, H; Van Effenterre, R

    2005-04-01

    An increasing number of studies are focusing on the anatomo-functional organisation of number processing and some cognitive models have been recently developed. Nevertheless, relationships between areas implicated in number processing, and language areas and circuits remain unclear. Recently, Dehaene and Cohen, in their "triple-code model of number processing", (Dehaene and Cohen, 1995) distinguished two alternative number representation and processing systems: one depending on verbal processes, the other representing a quantity manipulation. According to this model, the retrieval of "arithmetical facts" (AF), learned by rote at school and memorised in a verbal form (such as the multiplication table or simple addition problems) can be considered as a verbal automatism; conversely, subtraction problems, which require mental manipulation of the quantities, represent an abstract, semantic elaboration: "Actual Calculation" (AC). The anatomical correlate of the retrieval of AF (depending on automatic verbal associations) seems to correspond to the left-hemispheric perisylvian areas, while impairment of the actual calculation (AC) depends on the intraparietal region, particularly in the left dominant hemisphere. The present study describes the neuropsychological assessment of three patients, tested after surgery for left parieto-occipital tumors. Two of them were affected by an anaplasic glioma, the third by a low-grade glioma. The cognitive evaluation included: words of Rey, numeral (directed and reversed) span, reading of "simple" numbers (from 1 to 10) and of "complex" numbers (many decimals), writing (dictation) and reading a standard text, finger denomination and right-left distinction. All patients showed language disturbances, dysgraphia and severe dyslexia. In reading numbers, we identified two types of errors: lexical and syntactic. "Lexical errors" consisted in a wrong choice among words in the number's lexicon. For instance, all patients made errors in reading "complex" numbers composed by many decimals, switching single numbers but respecting the decimal size and the structure of the whole number (such as 69107 instead of 68107). On the other hand, only one patient committed syntactic errors, misunderstanding the decimal size and the structure of the number. We considered lexical errors as verbal errors, and syntactic errors as semantic errors, affecting the notion of quantity. We tried to explain verbal disturbances as well as lexical errors as a consequence of lesion of the left-hemispheric perisylvian areas, while syntactic errors as a consequence of impairment of the intraparietal region. PMID:15924078

  11. Thermochemoradiation Therapy Using Superselective Intra-arterial Infusion via Superficial Temporal and Occipital Arteries for Oral Cancer With N3 Cervical Lymph Node Metastases

    SciTech Connect

    Mitsudo, Kenji, E-mail: mitsudo@yokohama-cu.ac.jp [Department of Oral and Maxillofacial Surgery, Yokohama City University Graduate School of Medicine, Yokohama (Japan)] [Department of Oral and Maxillofacial Surgery, Yokohama City University Graduate School of Medicine, Yokohama (Japan); Koizumi, Toshiyuki; Iida, Masaki; Iwai, Toshinori; Oguri, Senri [Department of Oral and Maxillofacial Surgery, Yokohama City University Graduate School of Medicine, Yokohama (Japan)] [Department of Oral and Maxillofacial Surgery, Yokohama City University Graduate School of Medicine, Yokohama (Japan); Yamamoto, Noriyuki [Department of Oral and Maxillofacial Surgery, Nagoya University Graduate School of Medicine, Nagoya (Japan)] [Department of Oral and Maxillofacial Surgery, Nagoya University Graduate School of Medicine, Nagoya (Japan); Itoh, Yoshiyuki [Department of Radiology, Nagoya University Graduate School of Medicine, Nagoya (Japan)] [Department of Radiology, Nagoya University Graduate School of Medicine, Nagoya (Japan); Kioi, Mitomu; Hirota, Makoto; Tohnai, Iwai [Department of Oral and Maxillofacial Surgery, Yokohama City University Graduate School of Medicine, Yokohama (Japan)] [Department of Oral and Maxillofacial Surgery, Yokohama City University Graduate School of Medicine, Yokohama (Japan)

    2012-08-01

    Purpose: To evaluate the therapeutic results and histopathological effects of treatment with thermochemoradiation therapy using superselective intra-arterial infusion via the superficial temporal and occipital arteries for N3 cervical lymph node metastases of advanced oral cancer. Methods and Materials: Between April 2005 and September 2010, 9 patients with N3 cervical lymph node metastases of oral squamous cell carcinoma underwent thermochemoradiation therapy using superselective intra-arterial infusion with docetaxel (DOC) and cisplatin (CDDP). Treatment consisted of hyperthermia (2-8 sessions), superselective intra-arterial infusions (DOC, total 40-60 mg/m{sup 2}; CDDP, total 100-150 mg/m{sup 2}) and daily concurrent radiation therapy (total, 40-60 Gy) for 4-6 weeks. Results: Six of 9 patients underwent neck dissection 5-8 weeks after treatment. In four of these 6 patients, all metastatic lymph nodes, including those at N3, were grade 3 (non-viable tumor cells present) or grade 4 (no tumor cells present) tumors, as classified by the system by Shimosato et al (Shimosato et al Jpn J Clin Oncol 1971;1:19-35). In 2 of these 6 patients, the metastatic lymph nodes were grade 2b (destruction of tumor structures with a small amount of residual viable tumor cells). The other 3 patients did not undergo neck dissection due to distant metastasis after completion of thermochemoradiation therapy (n=2) and refusal (n=1). The patient who refused neck dissection underwent biopsy of the N3 lymph node and primary sites and showed grade 3 cancer. During follow-up, 5 patients were alive without disease, and 4 patients died due to pulmonary metastasis (n=3) and noncancer-related causes (n=1). Five-year survival and locoregional control rates were 51% and 88%, respectively. Conclusions: Thermochemoradiation therapy using intra-arterial infusion provided good histopathologic effects and locoregional control rates in patients with N3 metastatic lymph nodes. However, patients with N3 metastatic lymph nodes experienced a high rate of distant metastases.

  12. Chronic stress effects on dendritic morphology in medial prefrontal cortex: sex differences and estrogen dependence

    Microsoft Academic Search

    J. E. Garrett; C. L. Wellman

    2009-01-01

    A growing body of work has documented sex differences in many behavioral, neurochemical, and morphological responses to stress. Chronic stress alters morphology of dendrites in medial prefrontal cortex in male rats. However, potential sex differences in stress-induced morphological changes in medial prefrontal cortex have not been examined. Thus, in Experiment 1 we assessed dendritic morphology in medial prefrontal cortex in

  13. Complementary roles of the rat prefrontal cortex and striatum in rewardbased learning and shifting navigation strategies

    E-print Network

    Paris-Sud XI, Université de

    Complementary roles of the rat prefrontal cortex and striatum in rewardbased learning and shifting Complementary roles of the rat prefrontal cortex and striatum in rewardbased learning and shifting navigation the roles of the rat prefrontal cortex and striatum in learning and shifting navigation strategies

  14. Ultrastructure of the outer cortex and the pia mater in man

    Microsoft Academic Search

    C. A. S. Lopes; W. G. P. Mair

    1974-01-01

    The pia mater consists of a single, interrupted layer of elongated cells which lie fairly close to the surface of the cortex. Granular material and some collagen fibres lie between the pial cells and the cortex, a greater amount of collagen being present where the pial cells are discontinuous. Basement membrane covers the outer aspect of the cortex, the outer

  15. Impaired Error-Likelihood Prediction in Medial Prefrontal Cortex in Schizophrenia

    E-print Network

    ÔØ Å ÒÙ× Ö ÔØ Impaired Error-Likelihood Prediction in Medial Prefrontal Cortex in Schizophrenia Prefrontal Cortex in Schizophrenia, NeuroImage (2010), doi: 10.1016/j.neuroimage.2010.09.027 This is a PDF-Likelihood Prediction in Medial Prefrontal Cortex in Schizophrenia Adam Krawitza* , Todd S. Braverb , Deanna M. Barchb

  16. Neural Correlates of Subsecond Time Distortion in the Middle Temporal Area of Visual Cortex

    E-print Network

    Neural Correlates of Subsecond Time Distortion in the Middle Temporal Area of Visual Cortex Navid G that both the duration and amplitude of the neural response in the middle temporal area of visual cortex internal clock, our results suggest that the known adaptive properties of neural activity in visual cortex

  17. Neurocomputing 70 (2007) 19141919 A neuronal model of the language cortex

    E-print Network

    Wennekers, Thomas

    2007-01-01

    ) inferior prefrontal and (v) premotor cortex (Broca areas), and (vi) primary motor cortex. Each ``area Wennekersb , Friedemann Pulvermu¨ llera a MRC Cognition and Brain Sciences Unit, 15, Chaucer Road language-learning processes in a brain-inspired model of the language cortex. The network consisted

  18. Cerebral Cortex doi:10.1093/cercor/bhm135

    E-print Network

    Cerebral Cortex doi:10.1093/cercor/bhm135 Cognitive Control, Goal Maintenance, and Prefrontal that age-related impairments in goal maintenance abilities cause a compensatory shift in older adults from a proactive (seen in young adults) to a reactive cognitive control strategy. Keywords: compensation, event

  19. Towards a circuit mechanism for movement tuning in motor cortex

    PubMed Central

    Harrison, Thomas C.; Murphy, Timothy H.

    2013-01-01

    The firing rates of neurons in primate motor cortex have been related to multiple parameters of voluntary movement. This finding has been corroborated by stimulation-based studies that have mapped complex movements in rodent and primate motor cortex. However, it has been difficult to link the movement tuning of a neuron with its role within the cortical microcircuit. In sensory cortex, neuronal tuning is largely established by afferents delivering information from tuned receptors in the periphery. Motor cortex, which lacks the granular input layer, may be better understood by analyzing its efferent projections. As a primary source of cortical output, layer 5 neurons represent an ideal starting point for this line of experimentation. It is in these deep output layers that movements can most effectively be evoked by intracortical microstimulation and recordings can obtain the most useful signals for the control of motor prostheses. Studies focused on layer 5 output neurons have revealed that projection identity is a fundamental property related to the laminar position, receptive field and ion channel complement of these cells. Given the variety of brain areas targeted by layer 5 output neurons, knowledge of a neuron's downstream connectivity may provide insight into its movement tuning. Future experiments that relate motor behavior to the activity of neurons with a known projection identity will yield a more detailed understanding of the function of cortical microcircuits. PMID:23346050

  20. High-Frequency Network Oscillations in Cerebellar Cortex

    Microsoft Academic Search

    Steven J. Middleton; Claudia Racca; Mark O. Cunningham; Roger D. Traub; Hannah Monyer; Thomas Knöpfel; Ian S. Schofield; Alistair Jenkins; Miles A. Whittington

    2008-01-01

    SUMMARY Both cerebellum and neocortex receive input from the somatosensory system. Interaction between these regions has been proposed to underpin the correct selection and execution of motor commands, but it is not clear how such interactions occur. In neo- cortex, inputs give rise to population rhythms, pro- viding a spatiotemporal coding strategy for inputs and consequent outputs. Here, we show

  1. Local landmark-based mapping of human auditory cortex

    Microsoft Academic Search

    Xiaojian Kang; Olivier Bertrand; Kimmo Alho; E. William Yund; Timothy J. Herron; David L. Woodsa

    2004-01-01

    Mammalian sensory cortex is functionally partitioned into cortical fields that are specialized for different processing operations. In theory, averaging functional and anatomical images across subjects can reveal both the average anatomy and the mean functional organization of sensory regions. However, this averaging process must overcome at least two obstacles: (1) the relative locations and sizes of cortical sensory areas vary

  2. Cerebral Cortex doi:10.1093/cercor/bhr162

    E-print Network

    did the control group. Finally, the autism group had decreased structural connectivity as measured). The underconnectivity theory is also supported by evidence of disrupted structural connectivity in autism as measuredCerebral Cortex doi:10.1093/cercor/bhr162 Distinctive Neural Processes during Learning in Autism

  3. Flexible neural mechanisms of cognitive control within human prefrontal cortex

    E-print Network

    , before the occurrence of cognitively de- manding events, to optimally bias attention, perception, and acFlexible neural mechanisms of cognitive control within human prefrontal cortex Todd S. Braver1 that different cognitive control processes may be im- plemented within the same brain regions, with fractionation

  4. Fourier analysis and spatial representation in the visual cortex

    Microsoft Academic Search

    J. J. Kulikowski; P. O. Bishop

    1981-01-01

    Summary Simple cells in the cat visual cortex are shown to be general purpose analyzers of visual information achieving, at the same time, minimum uncertainty in spatial localization and spatial frequency. Their responses to moving bars, edges and gratings are linearly interrelated and predictable from each other.

  5. Order and Magnitude Share a Common Representation in Parietal Cortex

    E-print Network

    Jonides, John

    Order and Magnitude Share a Common Representation in Parietal Cortex Michael S. Franklin1 and John magnitude is well established. Recently, there has also been speculation that the IPS is involved in the rep paradigms in which participants make judgments about either magnitude and/or order result in a behavioral

  6. Spatial Working Memory Effects in Early Visual Cortex

    ERIC Educational Resources Information Center

    Munneke, Jaap; Heslenfeld, Dirk J.; Theeuwes, Jan

    2010-01-01

    The present study investigated how spatial working memory recruits early visual cortex. Participants were required to maintain a location in working memory while changes in blood oxygen level dependent (BOLD) signals were measured during the retention interval in which no visual stimulation was present. We show working memory effects during the…

  7. Supra-modal role for frontal cortex in sensory gating

    Microsoft Academic Search

    S. M. Bowyer; N. Boutros; O. Korzyukov; N. Tepley

    2007-01-01

    The objective of this study was to determine if there is a cortical source in the frontal cortex that plays a role in somatosensory gating. Ten normal controls (aged 32±10 years) were monitored with MEG. Somatosensory evoked fields (SEF's) were measured during presentation of pressure pulses to the middle finger. The right hand was tested first then the left. Pulse #2

  8. Fast thermal waves spreading over the cerebral cortex

    Microsoft Academic Search

    I. A. Shevelev; E. N. Tsicalov

    1997-01-01

    Fast thermal waves spreading over the cerebral cortex were found in the white rat by infrared neuroimaging (thermoencephaloscopy) in the range of 3–5 pun. Thermal waves appeared under visual stimulation (the probability of their appearance = 0.92), and under background conditions (probability of appearance = 0.42). Typically, they moved during the period from 15 s before to 25 s after

  9. Patterns of intrinsic and associational circuitry in monkey prefrontal cortex

    Microsoft Academic Search

    Michele L. Pucak; Jonathan B. Levitt; Jennifer S. Lund; David A. Lewis

    1996-01-01

    Both local and long-range connections are critical mediators of information processing in the cerebral cortex, but little is known about the relationships among these types of connections, especially in higher-order cortical regions. We used quantitative reconstructions of the label arising from discrete (approximately 350 pm diameter) injections of biotinylated dextran amine and cholera toxin B to determine the spatial organization

  10. Primary and Secondary Auditory Cortex Stimulation for Intractable Tinnitus

    Microsoft Academic Search

    Dirk De Ridder; Gert De Mulder; Edwin Verstraeten; Karolien Van der Kelen; Stefan Sunaert; Marion Smits; Silvia Kovacs; Jan Verlooy; Paul Van de Heyning; Aage R. Moller

    2006-01-01

    Introduction: Recent research suggests tinnitus is a phantom phenomenon based on hyperactivity of the auditory system, which can be visualized by functional neuroimaging, and transiently modulated by transcranial magnetic stimulation (TMS). We present the results of the first implanted electrodes on the primary and secondary auditory cortex after a successful TMS suppression. Methods and Materials: Twelve patients underwent an auditory

  11. Tinnitus Intensity Dependent Gamma Oscillations of the Contralateral Auditory Cortex

    E-print Network

    Paris-Sud XI, Université de

    Tinnitus Intensity Dependent Gamma Oscillations of the Contralateral Auditory Cortex Elsa van der and Interdisciplinary Neuromodulation (BRAI2 N), University Hospital Antwerp, Antwerp, Belgium, 2 Tinnitus Research (CNRS), GIPSA-lab, Grenoble, France Abstract Background: Non-pulsatile tinnitus is considered

  12. Pre-attentive segmentation in the primary visual cortex

    Microsoft Academic Search

    Zhaoping Li

    2000-01-01

    The activities of neurons in primary visual cortex have been shown to be signié cantly inè uenced by stimuli outside their classical receptive é elds. We propose that these contextual inè uences serve pre-attentive visual segmentation by causing relatively higher neural responses to important or conspicuous image locations, making them more salient for perceptual pop-out. These locations include boundaries between

  13. Heterogeneity in the pyramidal network of the medial prefrontal cortex

    E-print Network

    Cai, Long

    Heterogeneity in the pyramidal network of the medial prefrontal cortex Yun Wang1, Henry Markram2, presumed to be the basis of working memory. The pyramidal network that supports this activity is unknown interconnecting distinct subnetworks of different pyramidal cells. One subnetwork was similar to the pyramidal

  14. Spectral mixing of rhythmic neuronal signals in sensory cortex

    E-print Network

    Kleinfeld, David

    Spectral mixing of rhythmic neuronal signals in sensory cortex Kurt F. Ahrens , Herbert Levine that such mixing is likely to occur in the mammalian nervous system as a means to compare two rhythmic sensory signals, such as occurs in human audition, and as a means to lock an intrinsic rhythm to a sensory input

  15. Prefrontal Cortex Contributions to Episodic Retrieval Monitoring and Evaluation

    ERIC Educational Resources Information Center

    Cruse, Damian; Wilding, Edward L.

    2009-01-01

    Although the prefrontal cortex (PFC) plays roles in episodic memory judgments, the specific processes it supports are not understood fully. Event-related potential (ERP) studies of episodic retrieval have revealed an electrophysiological modulation--the right-frontal ERP old/new effect--which is thought to reflect activity in PFC. The functional…

  16. Sparse Representation of Sounds in the Unanesthetized Auditory Cortex

    E-print Network

    Zadorlab, Tony

    in the auditory cortex represent acoustic stimuli? Although sound-evoked neural responses in the anesthetized of neurons engaged by acoustic stimuli (tones, frequency modulated sweeps, white-noise bursts, and natural receptive field. At the other extreme, the neural representation could be sparse, at any moment of time

  17. Valuation of uncertain and delayed rewards in primate prefrontal cortex

    PubMed Central

    Kim, Soyoun; Hwang, Jaewon; Seo, Hyojung; Lee, Daeyeol

    2009-01-01

    Humans and animals often must choose between rewards that differ in their qualities, magnitudes, immediacy, and likelihood, and must estimate these multiple reward parameters from their experience. However, the neural basis for such complex decision making is not well understood. To understand the role of the primate prefrontal cortex in determining the subjective value of delayed or uncertain reward, we examined the activity of individual prefrontal neurons during an inter-temporal choice task and a computer-simulated competitive game. Consistent with the findings from previous studies in humans and other animals, the monkey’s behaviors during inter-temporal choice were well accounted for by a hyperbolic discount function. In addition, the activity of many neurons in the lateral prefrontal cortex reflected the signals related to the magnitude and delay of the reward expected from a particular action, and often encoded the difference in temporally discounted values that predicted the animal’s choice. During a computerized matching pennies game, the animals approximated the optimal strategy, known as Nash equilibrium, using a reinforcement learning algorithm. We also found that many neurons in the lateral prefrontal cortex conveyed the signals related to the animal’s previous choices and their outcomes, suggesting that this cortical area might play an important role in forming associations between actions and their outcomes. These results show that the primate lateral prefrontal cortex plays a central role in estimating the values of alternative actions based on multiple sources of information. PMID:19375276

  18. Encoding and storage of spatial information in the retrosplenial cortex

    E-print Network

    Silva, Alcino

    of green fluorescent protein was under the control of the immediate early gene c-fos promoter as well- rhinal cortex (MEC) contains spatially modulated cells (grid cells) that fire at the nodes of a hexagonal lattice as the animal traverses its environment (2). Beyond hippocampal place cells and MEC grid cells

  19. Stress signalling pathways that impair prefrontal cortex structure and function

    Microsoft Academic Search

    Amy F. T. Arnsten

    2009-01-01

    The prefrontal cortex (PFC) — the most evolved brain region — subserves our highest-order cognitive abilities. However, it is also the brain region that is most sensitive to the detrimental effects of stress exposure. Even quite mild acute uncontrollable stress can cause a rapid and dramatic loss of prefrontal cognitive abilities, and more prolonged stress exposure causes architectural changes in

  20. Anterior Cingulate Cortex in Schema Assimilation and Expression

    ERIC Educational Resources Information Center

    Wang, Szu-Han; Tse, Dorothy; Morris, Richard G. M.

    2012-01-01

    In humans and in animals, mental schemas can store information within an associative framework that enables rapid and efficient assimilation of new information. Using a hippocampal-dependent paired-associate task, we now report that the anterior cingulate cortex is part of a neocortical network of schema storage with NMDA receptor-mediated…

  1. Anxiety and affective style: role of prefrontal cortex and amygdala

    Microsoft Academic Search

    Richard J. Davidson

    2002-01-01

    This article reviews the modern literature on two key aspects of the central circuitry of emotion: the prefrontal cortex (PFC) and the amygdala. There are several different functional divisions of the PFC, including the dorsolateral, ventromedial, and orbital sectors. Each of these regions plays some role in affective processing that shares the feature of representing affect in the absence of

  2. Role of the Primate Orbitofrontal Cortex in Mediating Anxious Temperament

    E-print Network

    Wisconsin at Madison, University of

    to understanding mechanisms underlying anxious temperament in humans. Key Words: Amygdala, anxiety, monkey anxious temperament and is a risk factor for the development of anxiety and affective disorders. Studies inhibition. The orbitofrontal cortex (OFC) and amygdala are part of a circuit involved in the processing

  3. Attentional Modulation in Visual Cortex Is Modified during Perceptual Learning

    ERIC Educational Resources Information Center

    Bartolucci, Marco; Smith, Andrew T.

    2011-01-01

    Practicing a visual task commonly results in improved performance. Often the improvement does not transfer well to a new retinal location, suggesting that it is mediated by changes occurring in early visual cortex, and indeed neuroimaging and neurophysiological studies both demonstrate that perceptual learning is associated with altered activity…

  4. Dynamics of Precise Spike Timing in Primary Auditory Cortex

    Microsoft Academic Search

    Mounya Elhilali; Jonathan B. Fritz; David J. Klein; Jonathan Z. Simon; Shihab A. Shamma

    2004-01-01

    Although single units in primary auditory cortex (A1) exhibit accurate timing in their phasic response to the onset of sound (precision of a few milliseconds), paradoxically, they are unable to sustain synchronized responses to repeated stimuli at rates much beyond 20 Hz. To explore the relationship between these two aspects of cortical response, we designed a broadband stimulus with a

  5. Sensory convergence in the parieto-insular vestibular cortex

    PubMed Central

    Shinder, Michael E.

    2014-01-01

    Vestibular signals are pervasive throughout the central nervous system, including the cortex, where they likely play different roles than they do in the better studied brainstem. Little is known about the parieto-insular vestibular cortex (PIVC), an area of the cortex with prominent vestibular inputs. Neural activity was recorded in the PIVC of rhesus macaques during combinations of head, body, and visual target rotations. Activity of many PIVC neurons was correlated with the motion of the head in space (vestibular), the twist of the neck (proprioceptive), and the motion of a visual target, but was not associated with eye movement. PIVC neurons responded most commonly to more than one stimulus, and responses to combined movements could often be approximated by a combination of the individual sensitivities to head, neck, and target motion. The pattern of visual, vestibular, and somatic sensitivities on PIVC neurons displayed a continuous range, with some cells strongly responding to one or two of the stimulus modalities while other cells responded to any type of motion equivalently. The PIVC contains multisensory convergence of self-motion cues with external visual object motion information, such that neurons do not represent a specific transformation of any one sensory input. Instead, the PIVC neuron population may define the movement of head, body, and external visual objects in space and relative to one another. This comparison of self and external movement is consistent with insular cortex functions related to monitoring and explains many disparate findings of previous studies. PMID:24671533

  6. Complementary Roles for Primate Frontal and Parietal Cortex in Guarding

    E-print Network

    Nieder, Andreas

    Neuron Article Complementary Roles for Primate Frontal and Parietal Cortex in Guarding Working and Gottlieb, 2013). These studies collectively suggest that attentional filtering per- formance in primates or rather restricted to particular situations. Specifically, it is unknown whether prefrontal sup- pression

  7. Neural substrates of vocalization feedback monitoring in primate auditory cortex

    E-print Network

    Wang, Xiaoqin

    LETTERS Neural substrates of vocalization feedback monitoring in primate auditory cortex Steven J the role of vocalization- induced suppression, remain virtually unknown. Here we show that neurons to passive listening5­10 . Similarly, investigations in non-human primates have demonstrated that most

  8. Reading Without the Left Ventral Occipito-Temporal Cortex

    ERIC Educational Resources Information Center

    Seghier, Mohamed L.; Neufeld, Nicholas H.; Zeidman, Peter; Leff, Alex P.; Mechelli, Andrea; Nagendran, Arjuna; Riddoch, Jane M.; Humphreys, Glyn W.; Price, Cathy J.

    2012-01-01

    The left ventral occipito-temporal cortex (LvOT) is thought to be essential for the rapid parallel letter processing that is required for skilled reading. Here we investigate whether rapid written word identification in skilled readers can be supported by neural pathways that do not involve LvOT. Hypotheses were derived from a stroke patient who…

  9. Delayed Maturation and Sensitive Periods in the Auditory Cortex

    Microsoft Academic Search

    Andrej Kral; Rainer Hartmann; Jochen Tillein; Silvia Heid; Rainer Klinke

    2001-01-01

    Behavioral data indicate the existence of sensitive periods in the development of audition and language. Neurophysiological data demonstrate deficits in the cerebral cortex of auditory-deprived animals, mainly in reduced cochleotopy and deficits in corticocortical and corticothalamic loops. In addition to current spread in the cochlea, reduced cochleotopy leads to channel interactions after cochlear implantation. Deficits in corticocortical and corticothalamic loops

  10. Membrane Potential and Firing Rate in Cat Primary Visual Cortex

    Microsoft Academic Search

    Matteo Carandini; David Ferster

    2000-01-01

    We have investigated the relationship between membrane po- tential and firing rate in cat visual cortex and found that the spike threshold contributes substantially to the sharpness of orientation tuning. The half-width at half-height of the tuning of the spike responses was 23 6 8°, compared with 38 6 15° for the membrane potential responses. Direction selectivity was also greater

  11. Development of Rostral Prefrontal Cortex and Cognitive and Behavioural Disorders

    ERIC Educational Resources Information Center

    Dumontheil, Iroise; Burgess, Paul W.; Blakemore, Sarah-Jayne

    2008-01-01

    Information on the development and functions of rostral prefrontal cortex (PFC), or Brodmann area 10, has been gathered from different fields, from anatomical development to functional neuroimaging in adults, and put forward in relation to three particular cognitive and behavioural disorders. Rostral PFC is larger and has a lower cell density in…

  12. Perirhinal cortex supports acquired fear of auditory objects

    Microsoft Academic Search

    Sun Jung Bang; Thomas H. Brown

    2009-01-01

    Damage to rat perirhinal cortex (PR) profoundly impairs fear conditioning to 22kHz ultrasonic vocalizations (USVs), but has no effect on fear conditioning to continuous tones. The most obvious difference between these two sounds is that continuous tones have no internal temporal structure, whereas USVs consist of strings of discrete calls separated by temporal discontinuities. PR was hypothesized to support the

  13. The onset of synaptogenesis in rat temporal cortex

    Microsoft Academic Search

    Norbert König; Gisèle Roch; Robert Marty

    1975-01-01

    The onset of synaptogenesis was studied in the temporal cortex of rat fetuses whose age ranged between 15 and 19 days of gestation. First synapses were found at a surprisingly early stage of cortical development: on day 16. These contacts showed relatively few vesicles and very inconspicuous membrane-thickenings. They were located in the marginal layer, above as well as below

  14. GABA as an Inhibitory Neurotransmitter in Human Cerebral Cortex

    Microsoft Academic Search

    DAVID A. MCCORMICK

    1989-01-01

    1. The possible role of y-aminobutyric acid (GABA) as an in- hibitory neurotransmitter in the human cerebral cortex was in- vestigated with the use of intracellular recordings from neocorti- cal slices maintained in vitro. 2. Electrical stimulation of afferents to presumed pyramidal cells resulted in an initial excitatory postsynaptic potential (EPSP) followed by fast and slow inhibitory postsynaptic potentials (IPSPs).

  15. Role of human prefrontal cortex in attention control.

    PubMed

    Knight, R T; Grabowecky, M F; Scabini, D

    1995-01-01

    Without a functioning dorsolateral prefrontal cortex, humans are stimulus bound and have little confidence in their ability to interact with the environment. Deficits in inhibitory control of external and internal processes coupled with impaired temporal coding of stimuli and detection capacity for novel events leave the patient functioning in a noisy internal environment without critical spatiotemporal cues. Some of these proposals are similar to those of Nauta (104). Based on connectivity of the prefrontal cortex, Nauta suggested that this region was ideally suited to generate and evaluate internal models of action. It is proposed that, in addition to this generation function, the prefrontal cortex is crucial for detecting changes in the external environment and for discriminating internally and externally derived models of the world. This chapter has described a cascade of deficits that result from damage to the dorsolateral prefrontal cortex. Awareness of the sensory world, and of the apparent stream of internal and external events, is impaired by deficits in novelty detection. Changes in the world, internal or external, may not be noticed in a noisy internal milieu. These deficits contribute to impaired reality monitoring and to a subsequent lack of confidence in behavior. An inability to bridge temporal gaps and temporally sequence internal events, together with deficits in inhibitory control systems, contribute to an impairment in the ability to generate coherent representations of alternate or counterfactual realities. PMID:7771302

  16. Gene expression in cortex and hippocampus during acute pneumococcal meningitis

    Microsoft Academic Search

    Roney S Coimbra; Veronique Voisin; Antoine B de Saizieu; Raija LP Lindberg; Matthias Wittwer; David Leppert; Stephen L Leib

    2006-01-01

    BACKGROUND: Pneumococcal meningitis is associated with high mortality (~30%) and morbidity. Up to 50% of survivors are affected by neurological sequelae due to a wide spectrum of brain injury mainly affecting the cortex and hippocampus. Despite this significant disease burden, the genetic program that regulates the host response leading to brain damage as a consequence of bacterial meningitis is largely

  17. Functional specialization of the primate frontal cortex during decision making.

    PubMed

    Lee, Daeyeol; Rushworth, Matthew F S; Walton, Mark E; Watanabe, Masataka; Sakagami, Masamichi

    2007-08-01

    Economic theories of decision making are based on the principle of utility maximization, and reinforcement-learning theory provides computational algorithms that can be used to estimate the overall reward expected from alternative choices. These formal models not only account for a large range of behavioral observations in human and animal decision makers, but also provide useful tools for investigating the neural basis of decision making. Nevertheless, in reality, decision makers must combine different types of information about the costs and benefits associated with each available option, such as the quality and quantity of expected reward and required work. In this article, we put forward the hypothesis that different subdivisions of the primate frontal cortex may be specialized to focus on different aspects of dynamic decision-making processes. In this hypothesis, the lateral prefrontal cortex is primarily involved in maintaining the state representation necessary to identify optimal actions in a given environment. In contrast, the orbitofrontal cortex and the anterior cingulate cortex might be primarily involved in encoding and updating the utilities associated with different sensory stimuli and alternative actions, respectively. These cortical areas are also likely to contribute to decision making in a social context. PMID:17670961

  18. An Amplitude Equation Approach to Contextual Effects in Visual Cortex

    Microsoft Academic Search

    Paul C. Bressloff; Jack D. Cowan

    2002-01-01

    A mathematical theory of interacting hypercolumns in primary visual cortex (V1) is presented that incorporates details concerning the anisotropic nature of long-range lateral connections. Each hypercolumn is modeled as a ring of interacting excitatory and inhibitory neural populations with orientation preferences over the range 0 to 180 degrees. Analytical methods from bifurcation theory are used to derive nonlinear equations for

  19. The functions of the orbitofrontal cortex Edmund T. Rolls*

    E-print Network

    Rolls, Edmund T.

    ) positive or negative reinforcer a taste or touch. A somatosensory input is revealed by neurons that respond are activated by pleasant touch, by painful touch, by taste, by smell, and by more abstract reinforcers such as winning or losing money. Damage to the orbitofrontal cortex can impair the learning and reversal

  20. Representation of Spatial Frequency and Orientation in the Visual Cortex

    Microsoft Academic Search

    R. M. Everson; A. K. Prashanth; M. Gabbay; B. W. Knight; L. Sirovich; E. Kaplan

    1998-01-01

    Knowledge of the response of the primary visual cortex to the various spatial frequencies and orientations in the visual scene should help us understand the principles by which the brain recognizes patterns. Current information about the cortical layout of spatial frequency response is still incomplete because of difficulties in recording and interpreting adequate data. Here, we report results from a

  1. TERMINATION OF AFFERENT AXONS IN MACAQUE STRIATE CORTEX1

    Microsoft Academic Search

    GARY G. BLASDEL; JENNIFER S. LUND

    1983-01-01

    We used horseradish peroxidase (HRP) to orthogradely label afferent axons in macaque striate cortex. Of the 38 axons that we recovered, nine were recorded intracelhrlarly before being filled with HRP. Light microscope and computer reconstructions of filled processes reveal highly stereotyped patterns of arborization and suggest that there are at least five discrete populations of lateral geniculate nucleus (LGN) afferent

  2. Networks within the orbital and medial prefrontal cortex

    Microsoft Academic Search

    J. L. Price

    1999-01-01

    The orbital and medial regions of the prefrontal cortex (OMPFC) can be divided into at least 22 architectonic areas, based on differences in staining with a number of methods and on differences in connections. The connections of these areas indicate that they can be divided into two interconnected groups or networks. The orbital network includes most of the areas on

  3. Development of functional organization of the pallid bat auditory cortex

    PubMed Central

    Razak, Khaleel A.; Fuzessery, Zoltan M.

    2007-01-01

    The primary auditory cortex is characterized by a tonotopic map and a clustered organization of binaural properties. The factors involved in the development of overlain representation of these two properties are unclear. We addressed this issue in the auditory cortex of the pallid bat. The adult pallid bat cortex contains a systematic relationship between best frequency (BF) and binaural properties. Most neurons with BF <30 kHz are binaurally inhibited (EO/I), while most neurons with BF >30 kHz are monaural (EO). As in other species, binaural properties are clustered. The EO/I cluster contains a systematic map of interaural intensity difference (IID) sensitivity. We asked if these properties are present at the time the bat acquires its full audible range (postnatal day [P] 15). Tonotopy, relationship between BF and binaural properties, and the map of IID sensitivity are adult-like at P15. However, binaural facilitation is only observed in pups older than P25. Frequency selectivity shows a BF-dependent sharpening during development. Thus, overlain representation of binaural properties and tonotopy in the pallid bat cortex is remarkably adult-like at an age when the full audible range is first present, suggesting an experience-independent development of overlapping feature maps. PMID:17321705

  4. Neural odometry: the discrete charm of the entorhinal cortex.

    PubMed

    Jeffery, Kathryn J

    2013-03-01

    A recent study finds that the grid reference system in entorhinal cortex, used for computing distances during self-localization, has a discretized and modular organization. This has implications both for how the system develops and also for how it functions. PMID:23473564

  5. SUPERIOR COLLICULUS LESIONS AND FLASH EVOKED POTENTIALS FROM RAT CORTEX

    EPA Science Inventory

    It is generally assumed that the primary response of the rat flash evoked potential (FEP) is activated by a retino-geniculate pathway, and that the second response reflects input to the cortex by way of the superior colliculus (SC) or other brainstem structures. In the present st...

  6. Cerebral Cortex doi:10.1093/cercor/bhs068

    E-print Network

    Nemeth, Dezso

    Cerebral Cortex doi:10.1093/cercor/bhs068 Boosting Human Learning by Hypnosis Dezso Nemeth1 in striatum-related procedural learning. In our study, hypnosis was used as a tool to reduce the competition between these 2 systems. We compared learning in hypnosis and in the alert state and found that hypnosis

  7. Auditory modulation of visual stimulus encoding in human retinotopic cortex

    PubMed Central

    de Haas, Benjamin; Schwarzkopf, D. Samuel; Urner, Maren; Rees, Geraint

    2013-01-01

    Sounds can modulate visual perception as well as neural activity in retinotopic cortex. Most studies in this context investigated how sounds change neural amplitude and oscillatory phase reset in visual cortex. However, recent studies in macaque monkeys show that congruence of audio-visual stimuli also modulates the amount of stimulus information carried by spiking activity of primary auditory and visual neurons. Here, we used naturalistic video stimuli and recorded the spatial patterns of functional MRI signals in human retinotopic cortex to test whether the discriminability of such patterns varied with the presence and congruence of co-occurring sounds. We found that incongruent sounds significantly impaired stimulus decoding from area V2 and there was a similar trend for V3. This effect was associated with reduced inter-trial reliability of patterns (i.e. higher levels of noise), but was not accompanied by any detectable modulation of overall signal amplitude. We conclude that sounds modulate naturalistic stimulus encoding in early human retinotopic cortex without affecting overall signal amplitude. Subthreshold modulation, oscillatory phase reset and dynamic attentional modulation are candidate neural and cognitive mechanisms mediating these effects. PMID:23296187

  8. Valuation of uncertain and delayed rewards in primate prefrontal cortex.

    PubMed

    Kim, Soyoun; Hwang, Jaewon; Seo, Hyojung; Lee, Daeyeol

    2009-04-01

    Humans and animals often must choose between rewards that differ in their qualities, magnitudes, immediacy, and likelihood, and must estimate these multiple reward parameters from their experience. However, the neural basis for such complex decision making is not well understood. To understand the role of the primate prefrontal cortex in determining the subjective value of delayed or uncertain reward, we examined the activity of individual prefrontal neurons during an inter-temporal choice task and a computer-simulated competitive game. Consistent with the findings from previous studies in humans and other animals, the monkey's behaviors during inter-temporal choice were well accounted for by a hyperbolic discount function. In addition, the activity of many neurons in the lateral prefrontal cortex reflected the signals related to the magnitude and delay of the reward expected from a particular action, and often encoded the difference in temporally discounted values that predicted the animal's choice. During a computerized matching pennies game, the animals approximated the optimal strategy, known as Nash equilibrium, using a reinforcement learning algorithm. We also found that many neurons in the lateral prefrontal cortex conveyed the signals related to the animal's previous choices and their outcomes, suggesting that this cortical area might play an important role in forming associations between actions and their outcomes. These results show that the primate lateral prefrontal cortex plays a central role in estimating the values of alternative actions based on multiple sources of information. PMID:19375276

  9. Perception and Action Selection Dissociate Human Ventral and Dorsal Cortex

    ERIC Educational Resources Information Center

    Ikkai, Akiko; Jerde, Trenton A.; Curtis, Clayton E.

    2011-01-01

    We test theories about the functional organization of the human cortex by correlating brain activity with demands on perception versus action selection. Subjects covertly searched for a target among an array of 4, 8, or 12 items (perceptual manipulation) and then, depending on the color of the array, made a saccade toward, away from, or at a right…

  10. Genetic Instructions and Developmental Plasticity in the Kitten's Visual Cortex

    Microsoft Academic Search

    C. Blakemore; G. M. Jones

    1977-01-01

    Two major properties of neurons in the kitten's visual cortex, binocularity and orientation selectivity, are present when the eyes first open, and therefore can be established by genetic instructions alone. However, both of these attributes require visual experience for their maintenance or strengthening; and both can be rapidly modified by unusual kinds of experience. Alternating sequences of cells dominated by

  11. Multisensory integration: vision boosts information through suppression in auditory cortex.

    PubMed

    Ghazanfar, Asif A; Lemus, Luis

    2010-01-12

    Signals from non-primary modalities can influence neural activity in 'unimodal' sensory areas of the neocortex, but whether this 'extra-modal' influence has any relevant consequences for neural coding has been unclear. Recent findings show that vision enhances the information content of neural signals in auditory cortex, but in a counter-intuitive fashion. PMID:20152139

  12. Bump attractor dynamics in prefrontal cortex explains behavioral precision in

    E-print Network

    Bump attractor dynamics in prefrontal cortex explains behavioral precision in spatial working, Minneapolis MN 3 Wake Forest School of Medicine, Winston-Salem NC Keywords: Persistent activity, saccade is lacking, and to date no demonstration exists that bump attractor dynamics underlies spatial working memory

  13. A Computational Model of the Cerebral Cortex Thomas Dean

    E-print Network

    Dean, Thomas

    researchers to combine lessons learned from biology with state-of-the- art graphical-model and machine-learningA Computational Model of the Cerebral Cortex Thomas Dean Department of Computer Science Brown with both hard-wired connection schemes and structure-learning algorithms inspired by animal learn- ing

  14. Feedback of visual object information to foveal retinotopic cortex

    E-print Network

    Kanwisher, Nancy

    Feedback of visual object information to foveal retinotopic cortex Mark A Williams1,2, Chris I Kanwisher1,5 The mammalian visual system contains an extensive web of feedback connections projecting from by prior theories of feedback. This information was position invariant, correlated with perceptual

  15. The gateway hypothesis of rostral prefrontal cortex (area 10) function

    Microsoft Academic Search

    Paul W. Burgess; Iroise Dumontheil; Sam J. Gilbert

    2007-01-01

    One of the most fascinating puzzles in cognitive neuroscience concerns the functions of a large brain area known as the rostral prefrontal cortex (or Area 10). This is a sizeable brain region, which is especially large in humans compared with other animals, yet very little is known about what role it plays in cognition. This chapter contains three sections. The

  16. Investigations into the organization of information in sensory cortex

    Microsoft Academic Search

    Mathew E. Diamond; Rasmus S. Petersen; Justin A. Harris; Stefano Panzeri

    2003-01-01

    One might take the exploration of sensory cortex in the first decades of the last century as the opening chapter of modern neuroscience. The combined approaches of (i) measuring effects of restricted ablation on functional capacities, both in the clinic and the laboratory, together with (ii) anatomical investigations of cortical lamination, arealization, and connectivity, and (iii) the early physiological probing

  17. Sexual attraction enhances glutamate transmission in mammalian anterior cingulate cortex

    Microsoft Academic Search

    Long-Jun Wu; Susan S Kim; Xiangyao Li; Fuxing Zhang; Min Zhuo

    2009-01-01

    Functional human brain imaging studies have indicated the essential role of cortical regions, such as the anterior cingulate cortex (ACC), in romantic love and sex. However, the neurobiological basis of how the ACC neurons are activated and engaged in sexual attraction remains unknown. Using transgenic mice in which the expression of green fluorescent protein (GFP) is controlled by the promoter

  18. Controlling human striatal cognitive function via the frontal cortex.

    PubMed

    van Schouwenburg, Martine R; O'Shea, Jacinta; Mars, Rogier B; Rushworth, Matthew F S; Cools, Roshan

    2012-04-18

    Cognitive flexibility is known to depend on the striatum. However, the striatum does not act in isolation to bias cognitive flexibility. In particular, cognitive flexibility also implicates the frontal cortex. Here we tested the hypothesis that the human frontal cortex controls cognitive flexibility by regulating striatal function via topographically specific frontostriatal connections. To this end, we exploited a repetitive transcranial magnetic stimulation (TMS) protocol over frontal cortex that is known to increase dopamine release in the striatum. This intervention was combined with functional magnetic resonance imaging to determine the functional and topographic specificity of its consequences at the whole brain level. Participants were scanned both before and after off-line TMS while performing a cognitive switching task that is known to depend on a specific striatal substructure, the putamen. Frontal stimulation perturbed task-specific functional signals in the putamen, while reducing fronto-striatal functional connectivity. There were no such effects of TMS over the medial parietal cortex. These data strengthen the hypothesis that cognitive flexibility involves topographic frontal control of striatal function. PMID:22514324

  19. Impairment of motor cortex activation and deactivation in Parkinson's disease

    Microsoft Academic Search

    Robert Chen; Sameer Kumar; Rami R. Garg; Anthony E. Lang

    2001-01-01

    Objectives: To examine the time course of corticospinal excitability before and after voluntary movement in Parkinson's disease (PD).Methods: We studied 9 mild PD patients at least 12 h off medications and 11 healthy volunteers in a simple reaction time (RT) paradigm. Suprathreshold transcranial magnetic stimulation was delivered to the left motor cortex at intervals covering the periods before and after

  20. Amygdala, Medial Prefrontal Cortex, and Hippocampal Function in PTSD

    E-print Network

    Patel, Aniruddh D.

    Amygdala, Medial Prefrontal Cortex, and Hippocampal Function in PTSD LISA M. SHIN,a,b SCOTT L, and hippocampus in posttrau- matic stress disorder (PTSD). Neuroimaging research reviewed in this article reveals heightened amygdala responsivity in PTSD during symp- tomatic states and during the processing of trauma

  1. Cognitive and emotional influences in anterior cingulate cortex

    Microsoft Academic Search

    George Bush; Phan Luu; Michael I. Posner

    2000-01-01

    Anterior cingulate cortex (ACC) is a part of the brain’s limbic system. Classically, this region has been related to affect, on the basis of lesion studies in humans and in animals. In the late 1980s, neuroimaging research indicated that ACC was active in many studies of cognition. The findings from EEG studies of a focal area of negativity in scalp

  2. Cerebral Cortex doi:10.1093/cercor/bhm233

    E-print Network

    Cerebral Cortex doi:10.1093/cercor/bhm233 Hearing Loss Prevents the Maturation of GABAergic that sensorineural hearing loss (SNHL) in gerbils leads to smaller inhibitory potentials in L2/3 pyramidal neurons that they support, such as speech discrimination in background noise, can be compromised by hearing loss, and this

  3. Human Medial Frontal Cortex Activity Predicts Learning from Errors

    Microsoft Academic Search

    Robert Hester; Natalie Barre; Kevin Murphy; Tim J. Silk; Jason B. Mattingley

    2008-01-01

    Learning from errors is a critical feature of human cognition. It underlies our ability to adapt to changing environmental demands and to tune behavior for optimal performance. The posterior medial frontal cortex (pMFC) has been implicated in the evaluation of errors to control behavior, although it has not previously been shown that activity in this region predicts learning from errors.

  4. PRIMARY MOTOR CORTEX INFLUENCES ON THE DESCENDING AND ASCENDING SYSTEMS

    Microsoft Academic Search

    ANTONIO CANEDO

    1997-01-01

    The motor cortex plays a crucial role in the co-ordination of movement and posture. This is possible because the pyramidal tract fibres have access both directly and through collateral branches to structures governing eye, head, neck, trunk and limb musculature. Pyramidal tract axons also directly reach the dorsal laminae of the spinal cord and the dorsal column nuclei, thus aiding

  5. The third dimension in the primary visual cortex.

    PubMed

    Westheimer, Gerald

    2009-06-15

    Anatomical superposition of the cortical projections from the overlapping visual fields of the two eyes does not make it obvious how the disposition of objects in the third dimension is encoded. Hubel and Wiesel's demonstration that units in the primary visual cortex of the mammal respond preferentially to elongated contours of specific orientation encouraged the inquiry into whether binocular disparity might not similarly be represented as an attribute interdigitated within the orderly progression of position. When this was found to indeed be the case, this entrained a brisk research activity into the disparity of receptive fields of single units in the primary visual cortex and the influence on their response of the three-dimensional locations of outside world stimuli. That cells' preferred orientations covered the whole gamut whereas space perception required only horizontal disparity was an apparent paradox that needed resolution. A connection with an observer's stereoscopic performance was made by the discovery that cells in the primate primary visual cortex display good tuning to the disparity in random-dot stereograms. But a wide gap still remains between the properties of these cortical units and human stereo thresholds in simple target configurations, let alone depth judgments in which perceptual and cognitive factors enter. When the neural circuits in the primary visual cortex that are involved in processing depth are eventually traced in detail they will also need to have properties that allow for the plasticity in learning and experience. PMID:19525565

  6. Basilar artery pseudoaneurysm presenting at 5-month follow-up after traumatic atlanto-occipital dislocation in a 7-year-old girl treated with intracranial stent placement and coiling

    PubMed Central

    Griauzde, Julius; Gemmete, Joseph J; Chaudhary, Neeraj; Pandey, Aditya S; Garton, Hugh J

    2013-01-01

    Atlanto-occipital dislocation (AOD) is a grave injury that is rarely survivable. Patients who do survive often have long-term sequelae resulting from the intracranial damage sustained during the traumatic event. The high impact needed to cause AOD is translated to the intracranial vessels, which can lead to vascular injury. Pseudoaneurysm is one of the possible outcomes of damage to the vessel wall. We present a case of basilar artery pseudoaneurysm diagnosed 5?months after a traumatic AOD who was treated with intracranial stent placement and coiling. PMID:23389747

  7. The role of adenosine A 1 and A 2A receptors of entorhinal cortex on piriform cortex kindled seizures in rats

    Microsoft Academic Search

    Narges Hosseinmardi; Javad Mirnajafi-Zadeh; Yaghoub Fathollahi; Parviz Shahabi

    2007-01-01

    In this research the role of adenosine A1 and A2A receptors of the entorhinal cortex on piriform cortex kindled seizures was investigated. In piriform cortex kindled rats, N6-cyclohexyladenosine (CHA), a selective A1 receptor agonist, 1,3-dimethyl-8 cyclopenthylxanthine (CPT), a selective A1 receptor antagonist, CGS21680 hydrochloride (CGS), a selective A2A receptor agonist and ZM241385 (ZM), a selective A2A receptor antagonist were injected

  8. Surround suppression maps in the cat primary visual cortex

    PubMed Central

    Vanni, Matthieu P.; Casanova, Christian

    2013-01-01

    In the primary visual cortex and higher-order areas, it is well known that the stimulation of areas surrounding the classical receptive field of a neuron can inhibit its responses. In the primate area middle temporal (MT), this surround suppression was shown to be spatially organized into high and low suppression modules. However, such an organization has not been demonstrated yet in the primary visual cortex. Here, we used optical imaging of intrinsic signals to spatially evaluate surround suppression in the cat visual cortex. The magnitude of the response was measured in areas 17 and 18 for stimuli with different diameters, presented at different eccentricities. Delimited regions of the cortex were revealed by circumscribed stimulations of the visual field (“cortical response field”). Increasing the stimulus diameter increased the spread of cortical activation. In the cortical response field, the optimal stimulation diameter and the level of suppression were evaluated. Most pixels (?3/4) exhibited surround suppression profiles. The optimal diameter, corresponding to a population of receptive fields, was smaller in area 17 (22°) than in area 18 (36°) in accordance with electrophysiological data. No difference in the suppression strength was observed between both areas (A17: 25%, A18: 21%). Further analysis of our data revealed the presence of surround modulation maps, organized in low and high suppression domains. We also developed a statistical method to confirm the existence of this cortical map and its neuronal origin. The organization for center/surround suppression observed here at the level of the primary visual cortex is similar to those found in higher order areas in primates (e.g., area MT) and could represent a strategy to optimize figure ground discrimination. PMID:23630471

  9. Connections of Cat Auditory Cortex: I. Thalamocortical System

    PubMed Central

    Lee, Charles C.; Winer, Jeffery A.

    2008-01-01

    Despite the functional importance of the medial geniculate body (MGB) in normal hearing, many aspects of its projections to auditory cortex are unknown. We analyzed the MGB projections to thirteen auditory areas in the cat using two retrograde tracers to investigate thalamocortical nuclear origins, topography, convergence, and divergence. MGB divisions and auditory cortex areas were defined independently of the connectional results using architectonic, histochemical, and immunocytochemical criteria. Each auditory cortex area received a unique pattern of input from several MGB nuclei; and these patterns of input identify four groups of cortical areas distinguished by their putative functional affiliations: tonotopic, non-tonotopic, multisensory, and limbic. Each family of areas received projections from a functionally related set of MGB nuclei; some nuclei project to only a few a few areas (e.g., the MGB ventral division to tonotopic areas), and others project to all areas (e.g., the medial division input to every auditory cortical areas and to other regions). Projections to tonotopic areas had fewer nuclear origins than those to multisensory or limbic-affiliated fields. All projections were organized topographically, even those from non-tonotopic nuclei. The few divergent neurons (mean: 2%) are consistent with a model of multiple segregated streams ascending to auditory cortex. The expanded cortical representation of MGB auditory, multisensory, and limbic affiliated streams appears to be a primary facet of forebrain auditory function. The emergence of several auditory cortex representations of characteristic frequency may be a functional multiplication of the more limited maps in the MGB. This expansion suggests emergent cortical roles consistent with the divergence of thalamocortical connections. PMID:18271026

  10. Location and spatial profile of category-specific regions in human extrastriate cortex

    Microsoft Academic Search

    Mona Spiridon; Bruce Fischl; Nancy Kanwisher

    2006-01-01

    Subjects were scanned in a single functional MRI (fMRI) experiment that enabled us to localize cortical regions in each subject in the occipital and temporal lobes that responded significantly in a variety of contrasts: faces objects, body parts objects, scenes objects, objects scrambled objects, and moving stationary stimuli. The resulting activation maps were coregistered across subjects using spherical surface coordinates

  11. The response of face-selective cortex with single face parts and part combinations

    E-print Network

    James, Thomas

    recognition Face recognition fMRI Occipital face area Feature-based processing a b s t r a c t A critical issue in object recognition research is how the parts of an object are analyzed by the visual system. This is particularly true of the research on face recognition, and especially with questions related to the neural

  12. Cerebral Cortex October 2008;18:2416--2438 doi:10.1093/cercor/bhn002

    E-print Network

    Todd, James T.

    from texture (SfT) and shading. The stimuli included monocular images of randomly shaped 3D surfaces that the extraction of 3D SfT involves the bilateral caudal inferior temporal gyrus (caudal ITG), lateral occipital reported in the literature that have investigated the perceptual analysis of 3D shape from texture (3D SfT

  13. Multivariate Patterns in Object-Selective Cortex Dissociate Perceptual and Physical

    E-print Network

    Kanwisher, Nancy

    to the perceptual experience of shape. We used human functional MRI to measure the physical, behavioral, and neural, functional magnetic resonance imaging (fMRI) has identified a brain region known as lateral occipital complex scrambled images of everyday objects [2,3] and is thought to be critical for object recognition [4

  14. Dissociable Effects of Lesions to the Perirhinal Cortex and the Postrhinal Cortex on Memory for Context and Objects in Rats

    E-print Network

    Wagner, Anthony

    for Context and Objects in Rats G. Norman and M. J. Eacott University of Durham Memory for the context. Sham-operated rats explore familiar objects appearing in incongruent but familiar contexts more than appeared. At short delays, perirhinal cortex-lesioned rats were unimpaired on memory for object in context

  15. Impairments in visual discrimination learning and recognition memory produced by neurotoxic lesions of rhinal cortex in rhesus monkeys

    Microsoft Academic Search

    Mark G. Baxter; Elisabeth A. Murray

    2001-01-01

    Much work on the cognitive functions of the primate rhinal (i.e. entorhinal plus perirhinal) cortex has been based on aspiration lesions of this structure, which might disrupt fibres passing nearby and through the rhinal cortex in addition to removing the cell bodies of the rhinal cortex itself. To determine whether damage limited to the cell bodies of the rhinal cortex

  16. Cortical integration in the visual system of the macaque monkey: large-scale morphological differences in the pyramidal neurons in the occipital, parietal and temporal lobes.

    PubMed Central

    Elston, G N; Tweedale, R; Rosa, M G

    1999-01-01

    Layer III pyramidal neurons were injected with Lucifer yellow in tangential cortical slices taken from the inferior temporal cortex (area TE) and the superior temporal polysensory (STP) area of the macaque monkey. Basal dendritic field areas of layer III pyramidal neurons in area STP are significantly larger, and their dendritic arborizations more complex, than those of cells in area TE. Moreover, the dendritic fields of layer III pyramidal neurons in both STP and TE are many times larger and more complex than those in areas forming 'lower' stages in cortical visual processing, such as the first (V1), second (V2), fourth (V4) and middle temporal (MT) visual areas. By combining data on spine density with those of Sholl analyses, we were able to estimate the average number of spines in the basal dendritic field of layer III pyramidal neurons in each area. These calculations revealed a 13-fold difference in the number of spines in the basal dendritic field between areas STP and V1 in animals of similar age. The large differences in complexity of the same kind of neuron in different visual areas go against arguments for isopotentiality of different cortical regions and provide a basis that allows pyramidal neurons in temporal areas TE and STP to integrate more inputs than neurons in more caudal visual areas. PMID:10445291

  17. Plasticity of the visual cortex and treatment of amblyopia.

    PubMed

    Sengpiel, Frank

    2014-09-22

    Over the last 50 years, research into the developmental plasticity of the visual cortex has led to a growing understanding of first the causes and then of the underlying cellular mechanisms of amblyopia or 'lazy eye', the commonest childhood disorder of vision. While it is widely believed that amblyopia cannot be treated successfully after the age of about 7, recent animal studies have demonstrated that visual cortex plasticity can be restored or enhanced later in life, paving the way for new strategies for the treatment of amblyopia that attempt to remove molecular brakes on plasticity. In addition, both animal and human work has established that amblyopia is not simply a monocular deficit, and therefore the most promising new non-invasive approaches force the two eyes to cooperate as opposed to conventional procedures that severely penalise the good eye. PMID:25247373

  18. Insight without cortex: lessons from the avian brain.

    PubMed

    Kirsch, Janina A; Güntürkün, Onur; Rose, Jonas

    2008-06-01

    Insight is a cognitive feature that is usually regarded as being generated by the neocortex and being present only in humans and possibly some closely related primates. In this essay we show that especially corvids display behavioral skills within the domains of object permanence, episodic memory, theory of mind, and tool use/causal reasoning that are insightful. These similarities between humans and corvids at the behavioral level are probably the result of a convergent evolution. Similarly, the telencephalic structures involved in higher cognitive functions in both species show a high degree of similarity, although the forebrain of birds has no cortex-like lamination. The neural substrate for insight-related cognitive functions in mammals and birds is thus not necessarily based on a laminated cortical structure but can be generated by differently organized forebrains. Hence, neither is insight restricted to mammals, as predicted from a "scala naturae", nor is the laminated cortex a prerequisite for the highest cognitive functions. PMID:18440242

  19. Symmetry activates extrastriate visual cortex in human and nonhuman primates

    PubMed Central

    Sasaki, Yuka; Vanduffel, Wim; Knutsen, Tamara; Tyler, Christopher; Tootell, Roger

    2005-01-01

    Humans often create and appreciate visual symmetry in their environment, and the underlying brain mechanisms have been a topic of increasing interest. Here, symmetric versus random dot stimuli produced robust functional MRI (fMRI) activity in higher-order regions of human visual cortex (especially areas V3A, V4, V7, and LO) but little activity elsewhere in brain. This fMRI response was found both with and without attention controls. Moreover, it was highly correlated with the psychophysical perception of symmetry. Similar symmetry responses were found by using line-based and dot stimuli and were found at a wide range of stimulus sizes and geometric configurations. Weaker symmetry responses were found in analogous regions of macaque visual cortex by using fMRI techniques with higher sensitivity. This evidence suggests that visual symmetry is specifically enhanced in the human brain, but that the underlying neural mechanisms may nevertheless be resolvable in nonhuman primates. PMID:15710884

  20. Attention modulates synchronized neuronal firing in primate somatosensory cortex

    NASA Astrophysics Data System (ADS)

    Steinmetz, P. N.; Roy, A.; Fitzgerald, P. J.; Hsiao, S. S.; Johnson, K. O.; Niebur, E.

    2000-03-01

    A potentially powerful information processing strategy in the brain is to take advantage of the temporal structure of neuronal spike trains. An increase in synchrony within the neural representation of an object or location increases the efficacy of that neural representation at the next synaptic stage in the brain; thus, increasing synchrony is a candidate for the neural correlate of attentional selection. We investigated the synchronous firing of pairs of neurons in the secondary somatosensory cortex (SII) of three monkeys trained to switch attention between a visual task and a tactile discrimination task. We found that most neuron pairs in SII cortex fired synchronously and, furthermore, that the degree of synchrony was affected by the monkey's attentional state. In the monkey performing the most difficult task, 35% of neuron pairs that fired synchronously changed their degree of synchrony when the monkey switched attention between the tactile and visual tasks. Synchrony increased in 80% and decreased in 20% of neuron pairs affected by attention.