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Sample records for occipital cortex loc

  1. Disambiguating the roles of area V1 and the lateral occipital complex (LOC) in contour integration

    PubMed Central

    Shpaner, Marina; Molholm, Sophie; Forde, Emma-Jane; Foxe, John J.

    2013-01-01

    Contour integration, the linking of collinear but disconnected visual elements across space, is an essential facet of object and scene perception. Here, we set out to arbitrate between two previously advanced mechanisms of contour integration: serial facilitative interactions between collinear cells in the primary visual cortex (V1) versus pooling of inputs in higher-order visual areas. To this end, we used high-density electrophysiological recordings to assess the spatio-temporal dynamics of brain activity in response to Gabor contours embedded in Gabor noise (so-called “pathfinder displays”) versus control stimuli. Special care was taken to elicit and detect early activity stemming from the primary visual cortex, as indexed by the C1 component of the visual evoked potential. Arguing against a purely early V1 account, there was no evidence for contour-related modulations within the C1 timeframe (50-100 msecs). Rather, the earliest effects were observed within the timeframe of the N1 component (160-200 msecs) and inverse source analysis pointed to principle generators in the lateral occipital complex (LOC) within the ventral visual stream. Source anlaysis also suggested that it was only during this relatively late processing period that contextual effects emerged in hierarchically early visual regions (i.e. V1/V2), consistent with a more distributed process involving recurrent feedback/feedforward interactions between LOC and early visual sensory regions. The distribution of effects uncovered here is consistent with pooling of information in higher order cortical areas as the initial step in contour integration, and that this pooling occurs relatively late in processing rather than during the initial sensory-processing period. PMID:23201366

  2. Neural Associations of the Early Retinotopic Cortex with the Lateral Occipital Complex during Visual Perception

    PubMed Central

    Liang, Bishan; Liu, Bo; Liu, Ming; Huang, Ruiwang

    2014-01-01

    Previous studies have demonstrated that the early retinotopic cortex (ERC, i.e., V1/V2/V3) is highly associated with the lateral occipital complex (LOC) during visual perception. However, it remains largely unclear how to evaluate their associations in quantitative way. The present study tried to apply a multivariate pattern analysis (MVPA) to quantify the neural activity in ERC and its association with that of the LOC when participants saw visual images. To this end, we assessed whether low-level visual features (Gabor features) could predict the neural activity in the ERC and LOC according to a voxel-based encoding model (VBEM), and then quantified the association of the neural activity between these regions by using an analogical VBEM. We found that the Gabor features remarkably predicted the activity of the ERC (e.g., the predicted accuracy was 52.5% for a participant) instead of that of the LOC (4.2%). Moreover, the MVPA approach can also be used to establish corresponding relationships between the activity patterns in the LOC and those in the ERC (64.2%). In particular, we found that the integration of the Gabor features and LOC visual information could dramatically improve the ‘prediction’ of ERC activity (88.3%). Overall, the present study provides new evidences for the possibility of quantifying the association of the neural activity between the regions of ERC and LOC. This approach will help to provide further insights into the neural substrates of the visual processing. PMID:25251083

  3. Language processing in the occipital cortex of congenitally blind adults

    E-print Network

    Bedny, Marina

    Language processing in the occipital cortex of congenitally blind adults Marina Bednya,b,1 , Alvaro in the left frontal and temporal cortex that are uniquely capable of language processing. However that this visual cortex activity in fact re ects language processing. We nd that in congenitally blind individuals

  4. Language processing in the occipital cortex of congenitally blind adults

    E-print Network

    Saxe, Rebecca

    Language processing in the occipital cortex of congenitally blind adults Marina Bednya,b,1 , Alvaro in the left frontal and temporal cortex that are uniquely capable of language processing. However that this visual cortex activity in fact reflects language processing. We find that in congenitally blind

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

    E-print Network

    Bedny, Marina

    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 ...

  6. 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

  7. Impossible expectations: fMRI adaptation in the lateral occipital complex (LOC) is modulated by the statistical regularities of 3D structural information.

    PubMed

    Freud, Erez; Ganel, Tzvi; Avidan, Galia

    2015-11-15

    fMRI adaptation (fMRIa), the attenuation of fMRI signal which follows repeated presentation of a stimulus, is a well-documented phenomenon. Yet, the underlying neural mechanisms supporting this effect are not fully understood. Recently, short-term perceptual expectations, induced by specific experimental settings, were shown to play an important modulating role in fMRIa. Here we examined the role of long-term expectations, based on 3D structural statistical regularities, in the modulation of fMRIa. To this end, human participants underwent fMRI scanning while performing a same-different task on pairs of possible (regular, expected) objects and spatially impossible (irregular, unexpected) objects. We hypothesized that given the spatial irregularity of impossible objects in relation to real-world visual experience, the visual system would always generate a prediction which is biased to the possible version of the objects. Consistently, fMRIa effects in the lateral occipital cortex (LOC) were found for possible, but not for impossible objects. Additionally, in alternating trials the order of stimulus presentation modulated LOC activity. That is, reduced activation was observed in trials in which the impossible version of the object served as the prime object (i.e. first object) and was followed by the possible version compared to the reverse order. These results were also supported by the behavioral advantage observed for trials that were primed by possible objects. Together, these findings strongly emphasize the importance of perceptual expectations in object representation and provide novel evidence for the role of real-world statistical regularities in eliciting fMRIa. PMID:26254586

  8. 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

  9. Language processing in the occipital cortex of congenitally blind

    E-print Network

    Bedny, Marina

    Humans are thought to have evolved brain regions in the left frontal and temporal cortex that are uniquely capable of language processing. However, congenitally blind individuals also activate the visual cortex in some ...

  10. Language processing in the occipital cortex of congenitally blind adults

    PubMed Central

    Bedny, Marina; Pascual-Leone, Alvaro; Dodell-Feder, David; Fedorenko, Evelina; Saxe, Rebecca

    2011-01-01

    Humans are thought to have evolved brain regions in the left frontal and temporal cortex that are uniquely capable of language processing. However, congenitally blind individuals also activate the visual cortex in some verbal tasks. We provide evidence that this visual cortex activity in fact reflects language processing. We find that in congenitally blind individuals, the left visual cortex behaves similarly to classic language regions: (i) BOLD signal is higher during sentence comprehension than during linguistically degraded control conditions that are more difficult; (ii) BOLD signal is modulated by phonological information, lexical semantic information, and sentence-level combinatorial structure; and (iii) functional connectivity with language regions in the left prefrontal cortex and thalamus are increased relative to sighted individuals. We conclude that brain regions that are thought to have evolved for vision can take on language processing as a result of early experience. Innate microcircuit properties are not necessary for a brain region to become involved in language processing. PMID:21368161

  11. The representation of objects in the human occipital and temporal cortex.

    PubMed

    Ishai, A; Ungerleider, L G; Martin, A; Haxby, J V

    2000-01-01

    Recently, we identified, using fMRI, three bilateral regions in the ventral temporal cortex that responded preferentially to faces, houses, and chairs [Ishai, A., Ungerleider, L. G., Martin, A., Schouten, J. L., & Haxby, J. V. (1999). Distributed representation of objects in the human ventral visual pathway. Proceedings of the National Academy of Sciences, U.S.A., 96, 9379--9384]. Here, we report differential patterns of activation, similar to those seen in the ventral temporal cortex, in bilateral regions of the ventral occipital cortex. We also found category-related responses in the dorsal occipital cortex and in the superior temporal sulcus. Moreover, rather than activating discrete, segregated areas, each category was associated with its own differential pattern of response across a broad expanse of cortex. The distributed patterns of response were similar across tasks (passive viewing, delayed matching) and presentation formats (photographs, line drawings). We propose that the representation of objects in the ventral visual pathway, including both occipital and temporal regions, is not restricted to small, highly selective patches of cortex but, instead, is a distributed representation of information about object form. Within this distributed system, the representation of faces appears to be less extensive as compared to the representations of nonface objects. PMID:11506646

  12. Role of the human retrosplenial cortex/parieto-occipital sulcus in perspective priming.

    PubMed

    Sulpizio, Valentina; Committeri, Giorgia; Lambrey, Simon; Berthoz, Alain; Galati, Gaspare

    2016-01-15

    The ability to imagine the world from a different viewpoint is a fundamental competence for spatial reorientation and for imagining what another individual sees in the environment. Here, we investigated the neural bases of such an ability using functional magnetic resonance imaging. Healthy participants detected target displacements across consecutive views of a familiar virtual room, either from the perspective of an avatar (primed condition) or in the absence of such a prime (unprimed condition). In the primed condition, the perspective at test always corresponded to the avatar's perspective, while in the unprimed condition it was randomly chosen as 0, 45 or 135deg of viewpoint rotation. We observed a behavioral advantage in performing a perspective transformation during the primed condition as compared to an equivalent amount of unprimed perspective change. Although many cortical regions (dorsal parietal, parieto-temporo-occipital junction, precuneus and retrosplenial cortex/parieto-occipital sulcus or RSC/POS) were involved in encoding and retrieving target location from different perspectives and were modulated by the amount of viewpoint rotation, the RSC/POS was the only area showing decreased activity in the primed as compared to the unprimed condition, suggesting that this region anticipates the upcoming perspective change. The retrosplenial cortex/parieto-occipital sulcus appears to play a special role in the allocentric coding of heading directions. PMID:26484830

  13. V1 surface size predicts GABA concentration in medial occipital cortex.

    PubMed

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

    2016-01-01

    A number of recent studies have established a link between behavior and the anatomy of the primary visual cortex (V1). However, one often-raised criticism has been that these studies provide little insight into the mechanisms of the observed relationships. As inhibitory neural interactions have been postulated as an important mechanism for those behaviors related to V1 anatomy, we measured the concentration of inhibitory gamma-amino butyric acid (GABA) in the medial occipital cortex where V1 is located using magnetic resonance spectroscopy (MRS) and estimated the surface area of V1 using fMRI retinotopic mapping. We found a significant positive relationship between GABA concentration and V1 surface area. This relationship was present irrespective of whether the MRS voxel had a fixed size across participants or was proportionally sized to each individual's V1 surface area. Hence, individuals with a larger V1 had a higher GABA concentration in the medial occipital cortex. By tying together V1 size and GABA concentration, our findings point towards individual differences in the level of neural inhibition that might partially mediate the relationships between behavior and V1 neuroanatomy. In addition, they illustrate how stable microscopic properties of neural activity and function are reflected in macro-measures of V1 structure. PMID:26416651

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

    PubMed Central

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

    2015-01-01

    The extent of visual cortex reorganization following injury remains controversial. We report serial functional magnetic resonance imaging (fMRI) data from a patient with sequential posterior circulation strokes occurring 3 weeks apart, compared with data from an age-matched healthy control subject. At 8 days following a left occipital stroke, contralesional visual cortical activation was within expected striate and extrastriate sites, comparable to that seen in controls. Despite a further infarct in the right (previously unaffected hemisphere), there was evolution of visual cortical reorganization progressed. In this patient, there was evidence of utilization of peri-infarct sites (right-sided) and recruitment of new activation sites in extrastriate cortices, including in the lateral middle and inferior temporal lobes. The changes over time corresponded topographically with the patient's lesion site and its connections. Reorganization of the surviving visual cortex was demonstrated 8 days after the first stroke. Ongoing reorganization in extant cortex was demonstrated at the 6 month scan. We present a summary of mechanisms of recovery following stroke relevant to the visual system. We conclude that mature primary visual cortex displays considerable plasticity and capacity to reorganize, associated with evolution of visual field deficits. We discuss these findings and their implications for therapy within the context of current concepts in visual compensatory and restorative therapies. PMID:25972800

  15. Is LOC Responsive to Object Familiarity?

    PubMed

    Shilowich, Bryan; Shah, Manan; Biederman, Irving; Tjan, Bosco; Keller, Brenton

    2015-09-01

    Malach et al. (1995) discovered that the lateral occipital cortex and the posterior fusiform gyrus, cortical areas that they termed the lateral occipital complex (LOC), yielded greater fMRI BOLD responses when viewing intact images of familiar objects than their scrambled versions (resembling texture). Malach et al. discounted a role of familiarity by showing that unfamiliar "abstract" Henry Moore sculptures also activated LOC more than its scrambled versions. Although such a comparison does indicate that intact images produce greater LOC activation than their scrambled versions, it is not clear, without control for lower-level stimulus features, whether there is, in fact, no effect of familiarity. There is strong evidence that LOC represents objects in terms of their parts (Hayworth & Biederman, 2006). We put this issue of object familiarity to test by comparing cortical activation to 72 familiar objects and their novel counterparts, produced by rearranging their simple geon-like parts, thus holding the part ensemble of an image constant while varying familiarity (Panel A of Fig). Each object was composed of three or more geons, with each geon corresponding to a simple part of the object. The intact minus scrambled versions of each object was used to define LOC itself. With subjects performing an orthogonal task, greater activation in LOC was found for the familiar compared to the novel objects (Panel B). There was no effect of object symmetry. Although novel objects produce greater BOLD activity in LOC than their scrambled versions, there was still greater activation for familiar objects than their novel arrangements. Meeting abstract presented at VSS 2015. PMID:26326300

  16. Resting-state connectivity and functional specialization in human medial parieto-occipital cortex.

    PubMed

    Tosoni, Annalisa; Pitzalis, Sabrina; Committeri, Giorgia; Fattori, Patrizia; Galletti, Claudio; Galati, Gaspare

    2015-11-01

    According to recent models of visuo-spatial processing, the medial parieto-occipital cortex is a crucial node of the dorsal visual stream. Evidence from neurophysiological studies in monkeys has indicated that the parieto-occipital sulcus (POS) contains three functionally and cytoarchitectonically distinct areas: the visual area V6 in the fundus of the POS, and the visuo-motor areas V6Av and V6Ad in a progressively dorsal and anterior location with respect to V6. Besides different topographical organization, cytoarchitectonics, and functional properties, these three monkey areas can also be distinguished based on their patterns of cortico-cortical connections. Thanks to wide-field retinotopic mapping, areas V6 and V6Av have been also mapped in the human brain. Here, using a combined approach of resting-state functional connectivity and task-evoked activity by fMRI, we identified a new region in the anterior POS showing a pattern of functional properties and cortical connections that suggests a homology with the monkey area V6Ad. In addition, we observed distinct patterns of cortical connections associated with the human V6 and V6Av which are remarkably consistent with those showed by the anatomical tracing studies in the corresponding monkey areas. Consistent with recent models on visuo-spatial processing, our findings demonstrate a gradient of functional specialization and cortical connections within the human POS, with more posterior regions primarily dedicated to the analysis of visual attributes useful for spatial navigation and more anterior regions primarily dedicated to analyses of spatial information relevant for goal-directed action. PMID:25096286

  17. Exploratory Metabolomic Analyses Reveal Compounds Correlated with Lutein Concentration in Frontal Cortex, Hippocampus, and Occipital Cortex of Human Infant Brain

    PubMed Central

    Lieblein-Boff, Jacqueline C.; Johnson, Elizabeth J.; Kennedy, Adam D.; Lai, Chron-Si; Kuchan, Matthew J.

    2015-01-01

    Lutein is a dietary carotenoid well known for its role as an antioxidant in the macula, and recent reports implicate a role for lutein in cognitive function. Lutein is the dominant carotenoid in both pediatric and geriatric brain tissue. In addition, cognitive function in older adults correlated with macular and postmortem brain lutein concentrations. Furthermore, lutein was found to preferentially accumulate in the infant brain in comparison to other carotenoids that are predominant in diet. While lutein is consistently related to cognitive function, the mechanisms by which lutein may influence cognition are not clear. In an effort to identify potential mechanisms through which lutein might influence neurodevelopment, an exploratory study relating metabolite signatures and lutein was completed. Post-mortem metabolomic analyses were performed on human infant brain tissues in three regions important for learning and memory: the frontal cortex, hippocampus, and occipital cortex. Metabolomic profiles were compared to lutein concentration, and correlations were identified and reported here. A total of 1276 correlations were carried out across all brain regions. Of 427 metabolites analyzed, 257 were metabolites of known identity. Unidentified metabolite correlations (510) were excluded. In addition, moderate correlations with xenobiotic relationships (2) or those driven by single outliers (3) were excluded from further study. Lutein concentrations correlated with lipid pathway metabolites, energy pathway metabolites, brain osmolytes, amino acid neurotransmitters, and the antioxidant homocarnosine. These correlations were often brain region—specific. Revealing relationships between lutein and metabolic pathways may help identify potential candidates on which to complete further analyses and may shed light on important roles of lutein in the human brain during development. PMID:26317757

  18. Differential alpha-mediated inhibition of dopamine and noradrenaline release in the parietal and occipital cortex following noradrenaline transporter blockade.

    PubMed

    Valentini, V; Cacciapaglia, F; Frau, R; Di Chiara, G

    2006-07-01

    Parietal and occipital cortices, while densely innervated by noradrenalin 2 (NA) projections, possess a comparatively sparse dopamine 2 (DA) innervation, even sparser than the prefrontal cortex. We previously reported that reboxetine and desipramine, two selective norepinephrine transporter (NET) blockers, at doses that maximally increase DA in the prefrontal cortex, do not increase DA in the parietal and occipital cortices. In the present study, we performed a full dose-response study of the effect of systemic reboxetine and desipramine on DA and NA in dialysates from the parietal and occipital cortices. Seven doses of reboxetine (0.1, 0.25, 0.5, 1.0, 2.5, 5.0 and 10 mg/kg) and four doses of desipramine (0.25, 1.0, 2.5 and 5.0 mg/kg) were tested. Reboxetine and desipramine differentially affected dialysate DA as compared with NA. Reboxetine increased DA maximally by about 100% after doses of 0.25-0.5 mg/kg and showed a bell-shaped dose-response function in both areas; desipramine did not affect DA in the parietal cortex and increased it in the occipital cortex only at 2.5 mg/kg. NA was maximally increased by 275% by 0.5-2.5 mg/kg reboxetine and by about 300% by 5.0 mg/kg desipramine with a more linear dose-response curve. The mechanism of peculiar dose-response function of dialysate DA after reboxetine and desipramine was further investigated by testing the effect of drugs on dialysate DA and NA under alpha(2) receptor blockade. Under local perfusion of the occipital cortex with idazoxan, an otherwise ineffective dose of reboxetine and desipramine (5 mg/kg) became effective in raising extracellular DA. In contrast, the effect of reboxetine on NA was potentiated, while that of desipramine was not affected. These results suggest that, in the parietal and occipital cortices, extracellular NA, raised by NET blockade, exerts a preferential inhibitory influence on DA release by acting on local alpha(2) receptors, thus accounting for the bell-shaped feature of the dose-response function of drugs on dialysate DA in these areas. PMID:16805801

  19. A short period of visual deprivation at birth triggers long-lasting crossmodal reorganization of the occipital cortex in humans.

    PubMed

    Collignon, Olivier; Dormal, Giulia; de Heering, Adelaide; Lepore, Franco; Lewis, Terri; Maurer, Daphne

    2015-09-01

    The study of sensory deprivation is a striking model to reveal the role experience plays in sculpting the functional architecture of the brain. Here we used functional Magnetic Resonance Imaging to characterize brain responses to auditory stimuli in 11 adults who had been deprived of all patterned vision at birth by dense congenital cataracts in both eyes until they were removed surgically at 9 to 238 days of age. When compared to a control group with typical vision, the cataract-recovery group showed enhanced auditory-driven activity in two focal bilateral visual regions (the superior occipital gyrus and the cuneus) classically considered retinotopic. The crossmodal activation of occipital regions correlated neither with visual acuity nor with the duration of deprivation in the cataract-recovery group. A combination of dynamic causal modeling with Bayesian model selection indicated that this auditory-driven activity in the occipital cortex was better explained by direct cortico-cortical connections with primary auditory cortex than by subcortical reorganizations. These results demonstrate that a short period of visual deprivation during the early sensitive period of brain development leads to enduring large-scale crossmodal reorganization of the brain circuitry typically dedicated to vision. Meeting abstract presented at VSS 2015. PMID:26325880

  20. Repetition Suppression for Speech Processing in the Associative Occipital and Parietal Cortex of Congenitally

    E-print Network

    ´, Grenoble, France, 3 De´partement de Linguistique, Universite´ du Que´bec a` Montre´al, Montre´al, Canada, 4 of cross-modal activation of visual cortex in the blind comes from three different but related sources

  1. Occipital Neuralgia

    MedlinePLUS

    NINDS Occipital Neuralgia Information Page Table of Contents (click to jump to sections) What is Occipital Neuralgia? Is there any treatment? ... being done? Clinical Trials Organizations What is Occipital Neuralgia? Occipital neuralgia is a distinct type of headache ...

  2. Alfred Walter Campbell and the visual functions of the occipital cortex.

    PubMed

    Macmillan, Malcolm

    2014-07-01

    In his pioneering cytoarchitectonic studies of the human brain, Alfred Walter Campbell identified two structurally different areas in the occipital lobes and assigned two different kinds of visual functions to them. The first area, the visuosensory, was essentially on the mesial surface of the calcarine fissure. It was the terminus of nervous impulses generated in the retina and was where simple visual sensations arose. The second area, the visuopsychic, which surrounded or invested the first, was where sensations were interpreted and elaborated into visual perceptions. I argue that Campbell's distinction between the two areas was the starting point for the eventual differentiation of areas V1-V5. After a brief outline of Campbell's early life and education in Australia and of his Scottish medical education and early work as a pathologist at the Lancashire County Lunatic Asylum at Rainhill near Liverpool, I summarise his work on the human brain. In describing the structures he identified in the occipital lobes, I analyse the similarities and differences between them and the related structures identified by Joseph Shaw Bolton. I conclude by proposing some reasons for how that work came to be overshadowed by the later studies of Brodmann and for the more general lack of recognition given Campbell and his work. Those reasons include the effect of the controversies precipitated by Campbell's alliance with Charles Sherrington over the functions of the sensory and motor cortices. PMID:23218905

  3. Dynamic modulation of local population activity by rhythm phase in human occipital cortex during a visual search task.

    PubMed

    Miller, Kai J; Hermes, Dora; Honey, Christopher J; Sharma, Mohit; Rao, Rajesh P N; den Nijs, Marcel; Fetz, Eberhard E; Sejnowski, Terrence J; Hebb, Adam O; Ojemann, Jeffrey G; Makeig, Scott; Leuthardt, Eric C

    2010-01-01

    Brain rhythms are more than just passive phenomena in visual cortex. For the first time, we show that the physiology underlying brain rhythms actively suppresses and releases cortical areas on a second-to-second basis during visual processing. Furthermore, their influence is specific at the scale of individual gyri. We quantified the interaction between broadband spectral change and brain rhythms on a second-to-second basis in electrocorticographic (ECoG) measurement of brain surface potentials in five human subjects during a visual search task. Comparison of visual search epochs with a blank screen baseline revealed changes in the raw potential, the amplitude of rhythmic activity, and in the decoupled broadband spectral amplitude. We present new methods to characterize the intensity and preferred phase of coupling between broadband power and band-limited rhythms, and to estimate the magnitude of rhythm-to-broadband modulation on a trial-by-trial basis. These tools revealed numerous coupling motifs between the phase of low-frequency (?, ?, ?, ?, and ? band) rhythms and the amplitude of broadband spectral change. In the ? and ? ranges, the coupling of phase to broadband change is dynamic during visual processing, decreasing in some occipital areas and increasing in others, in a gyrally specific pattern. Finally, we demonstrate that the rhythms interact with one another across frequency ranges, and across cortical sites. PMID:21119778

  4. Vision After Early-Onset Lesions of the Occipital Cortex: I. Neuropsychological and Psychophysical Studies

    PubMed Central

    Kiper, D. C.; Zesiger, P.; Maeder, P.; Deonna, T.; Innocenti, G. M.

    2002-01-01

    We analyzed the visual functions of two patients (MS, FJ) with bilateral lesion of the primary visual cortex, which occurred at gestational age 33 wk in MS and at postnatal month 7 in FJ. In both patients basic visual functions— visual acuity, contrast sensitivity, color, form, motion perception—are similarly preserved or modestly impaired. Functions requiring higher visual processing, particularly figure-ground segregation based on textural cues, are severely impaired. In MS, studied longitudinally, the deficits attenuated between the ages of 4.5 and 8 y, suggesting that the developing visual system can display a considerable degree of adaptive plasticity several years after the occurrence of a lesion. In FJ (age 18:9 to 20:6 y), who is more impaired, the recovery, if any, was less. PMID:12458786

  5. Occipital Alpha Activity during Stimulus Processing Gates the Information Flow to Object-Selective Cortex

    PubMed Central

    Zumer, Johanna M.; Scheeringa, René; Schoffelen, Jan-Mathijs; Norris, David G.; Jensen, Ole

    2014-01-01

    Given the limited processing capabilities of the sensory system, it is essential that attended information is gated to downstream areas, whereas unattended information is blocked. While it has been proposed that alpha band (8–13 Hz) activity serves to route information to downstream regions by inhibiting neuronal processing in task-irrelevant regions, this hypothesis remains untested. Here we investigate how neuronal oscillations detected by electroencephalography in visual areas during working memory encoding serve to gate information reflected in the simultaneously recorded blood-oxygenation-level-dependent (BOLD) signals recorded by functional magnetic resonance imaging in downstream ventral regions. We used a paradigm in which 16 participants were presented with faces and landscapes in the right and left hemifields; one hemifield was attended and the other unattended. We observed that decreased alpha power contralateral to the attended object predicted the BOLD signal representing the attended object in ventral object-selective regions. Furthermore, increased alpha power ipsilateral to the attended object predicted a decrease in the BOLD signal representing the unattended object. We also found that the BOLD signal in the dorsal attention network inversely correlated with visual alpha power. This is the first demonstration, to our knowledge, that oscillations in the alpha band are implicated in the gating of information from the visual cortex to the ventral stream, as reflected in the representationally specific BOLD signal. This link of sensory alpha to downstream activity provides a neurophysiological substrate for the mechanism of selective attention during stimulus processing, which not only boosts the attended information but also suppresses distraction. Although previous studies have shown a relation between the BOLD signal from the dorsal attention network and the alpha band at rest, we demonstrate such a relation during a visuospatial task, indicating that the dorsal attention network exercises top-down control of visual alpha activity. PMID:25333286

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

    PubMed

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

    2004-02-01

    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 alpha2 and 5-HT2 receptors, and of clozapine, an atypical antipsychotic, on dialysate DA in the medial PFCX, ParCX and OccCX was studied. We also assessed the influence of a prior 6-hydroxydopamine (6-OHDA) lesion of the dorsal noradrenergic bundle (DNAB) on the effect of reboxetine and clozapine on dialysate DA in the PFCX and ParCX. Systemic administration of reboxetine and desipramine dose-dependently increased dialysate DA in the PFCX but not in the ParCX and OccCX. In contrast, mianserin and clozapine raised dialysate DA in the ParCX and OccCX to an even larger extent than in the PFCX. 6-OHDA lesions of DNAB abolished the increase of dialysate DA elicited by reboxetine in the PFCX and by clozapine both in the PFCX and in the ParCX. It is concluded that, although PFCX and ParCX/OccCX share the presence of a strong control of DA transmission by NA through alpha2 receptors, they differ in the extent to which DA is cleared from the extracellular compartment by uptake through the NA transporter. This process, although extensive in the PFCX, appears insignificant in the ParCX and OccCX, probably as a result of the higher ratio of NA to DA resulting in exclusion of DA from NA transporter. PMID:14756813

  7. Crossmodal enhancement in the LOC for visuohaptic object recognition over development.

    PubMed

    Jao, R Joanne; James, Thomas W; James, Karin Harman

    2015-10-01

    Research has provided strong evidence of multisensory convergence of visual and haptic information within the visual cortex. These studies implement crossmodal matching paradigms to examine how systems use information from different sensory modalities for object recognition. Developmentally, behavioral evidence of visuohaptic crossmodal processing has suggested that communication within sensory systems develops earlier than across systems; nonetheless, it is unknown how the neural mechanisms driving these behavioral effects develop. To address this gap in knowledge, BOLD functional Magnetic Resonance Imaging (fMRI) was measured during delayed match-to-sample tasks that examined intramodal (visual-to-visual, haptic-to-haptic) and crossmodal (visual-to-haptic, haptic-to-visual) novel object recognition in children aged 7-8.5 years and adults. Tasks were further divided into sample encoding and test matching phases to dissociate the relative contributions of each. Results of crossmodal and intramodal object recognition revealed the network of known visuohaptic multisensory substrates, including the lateral occipital complex (LOC) and the intraparietal sulcus (IPS). Critically, both adults and children showed crossmodal enhancement within the LOC, suggesting a sensitivity to changes in sensory modality during recognition. These groups showed similar regions of activation, although children generally exhibited more widespread activity during sample encoding and weaker BOLD signal change during test matching than adults. Results further provided evidence of a bilateral region in the occipitotemporal cortex that was haptic-preferring in both age groups. This region abutted the bimodal LOtv, and was consistent with a medial to lateral organization that transitioned from a visual to haptic bias within the LOC. These findings converge with existing evidence of visuohaptic processing in the LOC in adults, and extend our knowledge of crossmodal processing in adults and children. PMID:26272239

  8. The development and organization of visuohaptic modality-biased signals in the LOC.

    PubMed

    Jao, R Joanne; James, Karin; James, Thomas

    2015-09-01

    Areas of the putative visual cortex are involved in combining multisensory information about object shape. In particular, the lateral occipital complex (LOC) is a known region involved in visuohaptic object recognition. Relative to adult research, there have been few studies investigating the development of crossmodal perception of visual and haptic information, and fewer still exploring the neural substrates of this ability. In the present study, BOLD fMRI was measured in children aged 7 to 8.5 years and in adults during intramodal (visual-to-visual, haptic-to-haptic) and crossmodal (visual-to-haptic, haptic-to-visual) delayed match-to-sample recognition tasks. In both children and adults, results indicated that the ventral occipitotemporal cortex followed a medial to lateral organization in which there was a visual to haptic bias in the mapping of sensory modalities used to process shape information. These areas were adjacent to (and on either side of) an overlapping bimodal region within the LOC (corresponding to LOtv). Additionally, results showed a crossmodal enhancement effect in which crossmodal matching produced greater activation than intramodal matching in the overlapping bimodal LOC region (LOtv), but not in the medial visual-preferring or lateral haptic-preferring areas of the LOC, suggesting that this bimodal region was sensitive to sensory changes. Finally, although children and adults did not differ qualitatively in the overall patterns of neural activity, children produced more widespread, but lower intensity, activation than adults. This suggests that fundamental neural support for visuohaptic object processing is present by 7 years, but requires fine-tuning to be adult-like. Finding a haptic-preferring region in the LOC suggests that the multisensory signals integrated in the LOtv likely arrive via neighboring modality-biased regions within the LOC itself. We hypothesize that these modality-biased regions transform somatosensory and visual signals to facilitate multisensory integration in the LOtv. A future step should be identifying the exact nature of those transformations. Meeting abstract presented at VSS 2015. PMID:26326548

  9. Fingerprints of Learned Object Recognition Seen in the fMRI Activation Patterns of Lateral Occipital Complex.

    PubMed

    Roth, Zvi N; Zohary, Ehud

    2015-09-01

    One feature of visual processing in the ventral stream is that cortical responses gradually depart from the physical aspects of the visual stimulus and become correlated with perceptual experience. Thus, unlike early retinotopic areas, the responses in the object-related lateral occipital complex (LOC) are typically immune to parameter changes (e.g., contrast, location, etc.) when these do not affect recognition. Here, we use a complementary approach to highlight changes in brain activity following a shift in the perceptual state (in the absence of any alteration in the physical image). Specifically, we focus on LOC and early visual cortex (EVC) and compare their functional magnetic resonance imaging (fMRI) responses to degraded object images, before and after fast perceptual learning that renders initially unrecognized objects identifiable. Using 3 complementary analyses, we find that, in LOC, unlike EVC, learned recognition is associated with a change in the multivoxel response pattern to degraded object images, such that the response becomes significantly more correlated with that evoked by the intact version of the same image. This provides further evidence that the coding in LOC reflects the recognition of visual objects. PMID:24692511

  10. Early occipital injury affects numerosity counting but not simple arithmetic.

    PubMed

    Zhang, Han; Chen, Chuansheng; Sun, Zhaohui; Lin, Jiuluan; Zhou, Wenjing; Zhou, Xinlin

    2016-02-01

    This study investigated the effects of early occipital injury on the development of counting and simple arithmetic abilities in an occipital epileptic patient. This patient had obvious softening lesions in the bilateral occipital regions due to viral encephalitis at the age of 1.5 years. Results showed that she could perform subitizing and simple arithmetic very well, but could not perform numerosity counting tasks. These results suggest that the occipital cortex plays an important role in the development of numerosity counting skills, but not in the development of subitizing and simple arithmetic. PMID:25771703

  11. Occipital and inferotemporal responses to visual signals in the monkey.

    PubMed

    Ashford, J W; Fuster, J M

    1985-11-01

    This study analyzes cellular and field-potential responses in striate and inferotemporal cortex to visual stimuli in monkeys performing a memory task (delayed matching-to-sample). Each trial was initiated by a brief alerting diffuse flash preceding presentation of the memorandum (sample); the latter was a lighted circle (red or green, 1.5 s) to be retained by the animal during a subsequent delay for correct behavioral response (color match). The alerting flash evoked distinct excitatory cell responses and field potentials in the occipital cortex; those two orders of phenomena were broadly related to each other in temporal terms. By contrast, most cells in the inferotemporal region were inhibited by the flash, although the local evoked field potential had a configuration similar to that of the occipital potential. In each region, the sample stimuli elicited excitatory unit responses which summed to a unimodal distribution with an initial component roughly corresponding in time course to the local field potential. Although the shortest response latencies were found in occipital cortex, considerable temporal overlap of the sample-related activities in the two cortices was observed. The finding that most inferotemporal cells, unlike occipital cells, treated only the sample with excitatory response indicates that the inferotemporal cortex is selectively attuned to visual detail. However, the largely simultaneous activation of both cortical regions following the onset of the sample suggests that discriminative visual information is processed by hierarchic interactions of the two cortices through their reciprocal connections. PMID:4054294

  12. Contextual influences on object representations in the occipito-temporal cortex.

    PubMed

    Cheung, Olivia; Caramazza, Alfonso

    2015-09-01

    What are the factors that determine how objects are represented in the visual system? Apart from visual shape, conceptual information such as animacy and object size has been established as major organizational principles for object representations in the occipito-temporal cortex. However, it remains unclear whether object representations may also be influenced by contextual information (i.e., where objects appear in the world). There has been debate regarding whether contextual information is retrieved when objects are seen, and whether the neural locus of contextual effect may be in the object-selective lateral occipital complex (LOC) or the scene-selective parahippocampal cortex (PHC). We examined how object representations in the occipito-temporal cortex may be influenced by animacy, object size, and context. We used 24 items, including 4 animals, 4 big and 4 small inanimate objects for each of 2 contexts (e.g., beach items: dolphin, lifeguard chair, goggles; house items: dog, coffee table, vase). Sixteen exemplars were included for each item. Using fMRI, neural responses for the 24 items were obtained when participants (n=15) performed a one-back task to match identical images. To analyze the nature of object representations, we first calculated representational similarity matrices (RSMs) on the neural response patterns for the 24 items in both the LOC and the PHC (defined in a separate localizer). We then correlated the neural RSMs with several candidate models of RSMs. We found that a RSM that incorporated the effects of animacy, object size, and context was significantly correlated with the RSMs in both LOC and PHC. The correlations were stronger compared to those with other candidate RSMs, which concerned only animacy and size, or animacy alone. These results suggest that contextual information is engaged, even when such information is task-irrelevant. It appears that multiple sources of object knowledge contribute to form object representations in the occipito-temporal cortex. Meeting abstract presented at VSS 2015. PMID:26326857

  13. 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 ...

  14. Voxel-based morphometry in patients with cryptogenic occipital epilepsies. Preliminary data.

    PubMed

    Bilo, L; De Leva, M F; Meo, R; Tortora, F; Esposito, F; Aragri, A; Elefante, A

    2010-03-01

    We evaluated the differences in grey matter concentration (GMC) by voxel-based morphometry (VBM) in patients with cryptogenic occipital epilepsies. VBM analysis was performed in 11 patients with cryptogenic occipital epilepsies compared to 11 healthy controls. VBM analysis in patients revealed focal areas of reduced GMC in the occipital cortex and, more interestingly, increased GMC in the midbrain tegmentum and basal ganglia (globus pallidus and thalamus). VBM may disclose slight structural abnormalities in the brain of cryptogenic epilepsy patients, not evident with standard MRI. To the best of our knowledge, this is the first literature report describing areas of altered GMC in patients with occipital epilepsy. We hypothesize that these findings might be related to epileptic discharges and/or their diffusion and suggest that midbrain, globus pallidus and thalamus may be part of a functional network originating from the occipital areas. PMID:24148329

  15. Decoding the content of visual short-term memory under distraction in occipital and parietal areas.

    PubMed

    Bettencourt, Katherine C; Xu, Yaoda

    2016-01-01

    Recent studies have provided conflicting accounts regarding where in the human brain visual short-term memory (VSTM) content is stored, with strong univariate fMRI responses being reported in superior intraparietal sulcus (IPS), but robust multivariate decoding being reported in occipital cortex. Given the continuous influx of information in everyday vision, VSTM storage under distraction is often required. We found that neither distractor presence nor predictability during the memory delay affected behavioral performance. Similarly, superior IPS exhibited consistent decoding of VSTM content across all distractor manipulations and had multivariate responses that closely tracked behavioral VSTM performance. However, occipital decoding of VSTM content was substantially modulated by distractor presence and predictability. Furthermore, we found no effect of target-distractor similarity on VSTM behavioral performance, further challenging the role of sensory regions in VSTM storage. Overall, consistent with previous univariate findings, our results indicate that superior IPS, but not occipital cortex, has a central role in VSTM storage. PMID:26595654

  16. Sex differences in interactions between nucleus accumbens and visual cortex by explicit visual erotic stimuli: an fMRI study.

    PubMed

    Lee, S W; Jeong, B S; Choi, J; Kim, J-W

    2015-09-01

    Men tend to have greater positive responses than women to explicit visual erotic stimuli (EVES). However, it remains unclear, which brain network makes men more sensitive to EVES and which factors contribute to the brain network activity. In this study, we aimed to assess the effect of sex difference on brain connectivity patterns by EVES. We also investigated the association of testosterone with brain connection that showed the effects of sex difference. During functional magnetic resonance imaging scans, 14 males and 14 females were asked to see alternating blocks of pictures that were either erotic or non-erotic. Psychophysiological interaction analysis was performed to investigate the functional connectivity of the nucleus accumbens (NA) as it related to EVES. Men showed significantly greater EVES-specific functional connection between the right NA and the right lateral occipital cortex (LOC). In addition, the right NA and the right LOC network activity was positively correlated with the plasma testosterone level in men. Our results suggest that the reason men are sensitive to EVES is the increased interaction in the visual reward networks, which is modulated by their plasma testosterone level. PMID:25971857

  17. On the concept of third occipital headache.

    PubMed Central

    Bogduk, N; Marsland, A

    1986-01-01

    One of the putative causes of headache is osteoarthritis of the C2-3 zygapophysial joint. A technique for blocking the third occipital nerve which innervates this joint was devised and used as a screening procedure for headache mediated by this nerve. Seven out of ten consecutive patients presenting with suspected cervical headache were found to suffer pain mediated by the third occipital nerve and stemming from a C2-3 zygapophysial joint. Because third occipital headache may be indistinguishable clinically from tension or other forms of headache, third occipital nerve blocks are advocated as means of establishing this largely unrecognised diagnosis. Images PMID:3018167

  18. Alterations of the occipital lobe in schizophrenia.

    PubMed

    Tohid, Hassaan; Faizan, Muhammad; Faizan, Uzma

    2015-07-01

    The relationship of the occipital lobe of the brain with schizophrenia is not commonly studied; however, this topic is considered an essential subject matter among clinicians and scientists. We conducted this systematic review to elaborate the relationship in depth. We found that most schizophrenic patients show normal occipital anatomy and physiology, a minority showed dwindled values, and some demonstrated augmented function and structure. The findings are laborious to incorporate within single disease models that present the involvement of the occipital lobe in schizophrenia. Schizophrenia progresses clinically in the mid-twenties and thirties and its prognosis is inadequate. Changes in the volume, the gray matter, and the white matter in the occipital lobe are quite evident; however, the mechanism behind this involvement is not yet fully understood. Therefore, we recommend further research to explore the occipital lobe functions and volumes across the different stages of schizophrenia. PMID:26166588

  19. Human occipital cortices differentially exert saccadic suppression: intracranial recording in children

    PubMed Central

    Uematsu, Mitsugu; Matsuzaki, Naoyuki; Brown, Erik C.; Kojima, Katsuaki; Asano, Eishi

    2013-01-01

    By repeating saccades unconsciously, humans explore the surrounding world every day. Saccades inevitably move external visual images across the retina at high velocity; nonetheless, healthy humans don’t perceive transient blurring of the visual scene during saccades. This perceptual stability is referred to as saccadic suppression. Functional suppression is believed to take place transiently in the visual systems, but it remains unknown how commonly or differentially the human occipital lobe activities are suppressed at the large-scale cortical network level. We determined the spatial-temporal dynamics of intracranially-recorded gamma activity at 80–150 Hz around spontaneous saccades under no-task conditions during wakefulness and those in darkness during REM sleep. Regardless of wakefulness or REM sleep, a small degree of attenuation of gamma activity was noted in the occipital regions during saccades, most extensively in the polar and least in the medial portions. Longer saccades were associated with more intense gamma-attenuation. Gamma-attenuation was subsequently followed by gamma-augmentation most extensively involving the medial and least involving the polar occipital region. Such gamma-augmentation was more intense during wakefulness and temporally locked to the offset of saccades. The polarities of initial peaks of perisaccadic event-related potentials (ERPs) were frequently positive in the medial and negative in the polar occipital regions. The present study, for the first time, provided the electrophysiological evidence that human occipital cortices differentially exert peri-saccadic modulation. Transiently suppressed sensitivity of the primary visual cortex in the polar region may be an important neural basis for saccadic suppression. Presence of occipital gamma-attenuation even during REM sleep suggests that saccadic suppression might be exerted even without external visual inputs. The primary visual cortex in the medial region, compared to the polar region, may be more sensitive to an upcoming visual scene provided at the offset of each saccade. PMID:23792979

  20. 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

  1. Social appraisal in chronic psychosis: Role of medial frontal and occipital networks

    PubMed Central

    Taylor, Stephan F.; Chen, Ashley C.; Tso, Ivy F.; Liberzon, Israel; Welsh, Robert C.

    2010-01-01

    Persons with schizophrenia often appraise other individuals as threatening or persecutory. To evaluate social appraisal in schizophrenia, we probed brain networks with a task in which subjects judged whether or not they liked face stimuli with emotional expressions. We predicted that appraising negative expressions would engage patients, more than controls, and negative faces would be related to higher levels of negative affect and produce increased activity in the medial frontal cortex, an area involved in social appraisal. Twenty-one stable outpatients with chronic non-affective psychosis (16 schizophrenic, 5 schizoaffective) and 21 healthy subjects underwent functional magnetic resonance imaging. Compared with the control subjects, patients were slower to respond, but particularly slow when they judged negatively-valenced faces, a slowness correlated with negative affect in the psychosis patients. Appraisal activated the medial prefrontal cortex (mPFC) across all face valences. For negative expressions, patients exhibited greater activation of the dorsal anterior cingulate cortex (dACC). A psychophysiological interaction analysis of the dACC revealed co-modulation of the mPFC in controls, significantly less in patients, and a trend for co-modulation of occipital cortex in the patients. Activity in occipital cortex correlated with poor social adjustment and impaired social cognition, and co-modulation of the occipital gyrus by the dACC was correlated with poorer social cognition. The findings link appraisal of negative affect with aberrant activation of the medial frontal cortex, while early sensory processing of this social cognitive task was linked with poor social function, reflecting either top down or bottom up influences. PMID:20797730

  2. Emotional face expression modulates occipital-frontal effective connectivity during memory formation in a bottom-up fashion

    PubMed Central

    Xiu, Daiming; Geiger, Maximilian J.; Klaver, Peter

    2015-01-01

    This study investigated the role of bottom-up and top-down neural mechanisms in the processing of emotional face expression during memory formation. Functional brain imaging data was acquired during incidental learning of positive (“happy”), neutral and negative (“angry” or “fearful”) faces. Dynamic Causal Modeling (DCM) was applied on the functional magnetic resonance imaging (fMRI) data to characterize effective connectivity within a brain network involving face perception (inferior occipital gyrus and fusiform gyrus) and successful memory formation related areas (hippocampus, superior parietal lobule, amygdala, and orbitofrontal cortex). The bottom-up models assumed processing of emotional face expression along feed forward pathways to the orbitofrontal cortex. The top-down models assumed that the orbitofrontal cortex processed emotional valence and mediated connections to the hippocampus. A subsequent recognition memory test showed an effect of negative emotion on the response bias, but not on memory performance. Our DCM findings showed that the bottom-up model family of effective connectivity best explained the data across all subjects and specified that emotion affected most bottom-up connections to the orbitofrontal cortex, especially from the occipital visual cortex and superior parietal lobule. Of those pathways to the orbitofrontal cortex the connection from the inferior occipital gyrus correlated with memory performance independently of valence. We suggest that bottom-up neural mechanisms support effects of emotional face expression and memory formation in a parallel and partially overlapping fashion. PMID:25954169

  3. [Simple partial seizure consisting of complex visual hallucinations due to left temporo-occipital lesion].

    PubMed

    Takahashi, N; Kawamura, M

    1996-05-01

    We report a case of simple partial seizure consisting of elementary visual hallucinations and complex visual hallucinations due to left temporo-occipital lesion. The patient was a 45-year-old right-handed female who has been suffering from paroxysmal visual hallucinations in her right visual field for 15 days before admission. The properties of the hallucinations included several round colorful figures, the upper torsos of people in red, and green trees. CT scan showed a small low density area which, limited to the basal part of the left temporal and occipital lobes, was complicated partially by a high density area that was thought to be calcified. On T2-weighted MRI images, the lesion was shown as a small oval-shaped high signal intensity area surrounded by a low signal intensity area, and from its characteristic findings, a cavernous angioma was suspected. On the EEG, epileptic discharge was observed in the area limited to the left occipital region when elementary visual hallucinations occurred, and high amplitude diffuse slow waves were revealed predominantly on the left when complex visual hallucinations developed. It was thought that elementary visual hallucinations occurred in this patient following epileptic discharge of the occipital lobe, and complex visual hallucinations developed secondarily to the discharge which expanded from the occipital lobe to the surrounding area. Considering the investigation of non-epileptic visual hallucinations that are observed in the hemianopic visual field, we believe that disturbances of function of the temporo-parietal lobes around the occipital visual cortex has an important role in causing the development of complex visual hallucinations. PMID:8905986

  4. Does Shape Discrimination by the Mouth Activate the Parietal and Occipital Lobes? – Near-Infrared Spectroscopy Study

    PubMed Central

    Kagawa, Tomonori; Narita, Noriyuki; Iwaki, Sunao; Kawasaki, Shingo; Kamiya, Kazunobu; Minakuchi, Shunsuke

    2014-01-01

    A cross-modal association between somatosensory tactile sensation and parietal and occipital activities during Braille reading was initially discovered in tests with blind subjects, with sighted and blindfolded healthy subjects used as controls. However, the neural background of oral stereognosis remains unclear. In the present study, we investigated whether the parietal and occipital cortices are activated during shape discrimination by the mouth using functional near-infrared spectroscopy (fNIRS). Following presentation of the test piece shape, a sham discrimination trial without the test pieces induced posterior parietal lobe (BA7), extrastriate cortex (BA18, BA19), and striate cortex (BA17) activation as compared with the rest session, while shape discrimination of the test pieces markedly activated those areas as compared with the rest session. Furthermore, shape discrimination of the test pieces specifically activated the posterior parietal cortex (precuneus/BA7), extrastriate cortex (BA18, 19), and striate cortex (BA17), as compared with sham sessions without a test piece. We concluded that oral tactile sensation is recognized through tactile/visual cross-modal substrates in the parietal and occipital cortices during shape discrimination by the mouth. PMID:25299397

  5. Headache Following Occipital Brain Lesion: A Case of Migraine Triggered by Occipital Spikes?

    PubMed

    Vollono, Catello; Mariotti, Paolo; Losurdo, Anna; Giannantoni, Nadia Mariagrazia; Mazzucchi, Edoardo; Valentini, Piero; De Rose, Paola; Della Marca, Giacomo

    2015-10-01

    This study describes the case of an 8-year-old boy who developed a genuine migraine after the surgical excision, from the right occipital lobe, of brain abscesses due to selective infestation of the cerebrum by Entamoeba histolytica. After the surgical treatment, the boy presented daily headaches with typical migraine features, including right-side parieto-temporal pain, nausea, vomiting, and photophobia. Electroencephalography (EEG) showed epileptiform discharges in the right occipital lobe, although he never presented seizures. Clinical and neurophysiological observations were performed, including video-EEG and polygraphic recordings. EEG showed "interictal" epileptiform discharges in the right occipital lobe. A prolonged video-EEG recording performed before, during, and after an acute attack ruled out ictal or postictal migraine. In this boy, an occipital lesion caused occipital epileptiform EEG discharges without seizures, probably prevented by the treatment. We speculate that occipital spikes, in turn, could have caused a chronic headache with features of migraine without aura. Occipital epileptiform discharges, even in absence of seizures, may trigger a genuine migraine, probably by means of either the trigeminovascular or brainstem system. PMID:25406125

  6. Occipital cortical proton MRS at 4 Tesla in human moderate MDMA polydrug users

    PubMed Central

    Cowan, Ronald L.; Bolo, Nicolas R.; Dietrich, Mary; Haga, Erica; Lukas, Scott E.; Renshaw, Perry F.

    2007-01-01

    The recreational drug MDMA (3,4, methylenedioxymethamphetamine; sold under the street name of Ecstasy) is toxic to serotonergic axons in some animal models of MDMA administration. In humans, MDMA use is associated with alterations in markers of brain function that are pronounced in occipital cortex. Among neuroimaging methods, magnetic resonance spectroscopy (MRS) studies of brain metabolites N-acetylaspartate (NAA) and myoinositol (MI) at a field strength of 1.5 Tesla (T) reveal inconsistent results in MDMA users. Because higher field strength proton MRS has theoretical advantages over lower field strengths, we used proton MRS at 4.0 T to study absolute concentrations of occipital cortical NAA and MI in a cohort of moderate MDMA users (n = 9) versus non-MDMA using (n = 7) controls. Mean NAA in non-MDMA users was 10.47 mM (± 2.51), versus 9.83 mM (± 1.94) in MDMA users. Mean MI in non-MDMA users was 7.43 mM (± 1.68), versus 6.57 mM (± 1.59) in MDMA users. There were no statistical differences in absolute metabolite levels for NAA and MI in occipital cortex of MDMA users and controls. These findings are not supportive of MDMA-induced alterations in NAA or MI levels in this small sample of moderate MDMA users. Limitations to this study suggest caution in the interpretation of these results. PMID:17574394

  7. Analysis of the volumetric relationship among human ocular, orbital and fronto-occipital cortical morphology.

    PubMed

    Masters, Michael; Bruner, Emiliano; Queer, Sarah; Traynor, Sarah; Senjem, Jess

    2015-10-01

    Recent research on the visual system has focused on investigating the relationship among eye (ocular), orbital, and visual cortical anatomy in humans. This issue is relevant in evolutionary and medical fields. In terms of evolution, only in modern humans and Neandertals are the orbits positioned beneath the frontal lobes, with consequent structural constraints. In terms of medicine, such constraints can be associated with minor deformation of the eye, vision defects, and patterns of integration among these features, and in association with the frontal lobes, are important to consider in reconstructive surgery. Further study is therefore necessary to establish how these variables are related, and to what extent ocular size is associated with orbital and cerebral cortical volumes. Relationships among these anatomical components were investigated using magnetic resonance images from a large sample of 83 individuals, which also included each subject's body height, age, sex, and uncorrected visual acuity score. Occipital and frontal gyri volumes were calculated using two different cortical parcellation tools in order to provide a better understanding of how the eye and orbit vary in relation to visual cortical gyri, and frontal cortical gyri which are not directly related to visual processing. Results indicated that ocular and orbital volumes were weakly correlated, and that eye volume explains only a small proportion of the variance in orbital volume. Ocular and orbital volumes were also found to be equally and, in most cases, more highly correlated with five frontal lobe gyri than with occipital lobe gyri associated with V1, V2, and V3 of the visual cortex. Additionally, after accounting for age and sex variation, the relationship between ocular and total visual cortical volume was no longer statistically significant, but remained significantly related to total frontal lobe volume. The relationship between orbital and visual cortical volumes remained significant for a number of occipital lobe gyri even after accounting for these cofactors, but was again found to be more highly correlated with the frontal cortex than with the occipital cortex. These results indicate that eye volume explains only a small amount of variation in orbital and visual cortical volume, and that the eye and orbit are generally more structurally associated with the frontal lobes than they are functionally associated with the visual cortex of the occipital lobes. Results also demonstrate that these components of the visual system are highly complex and influenced by a multitude of factors in humans. PMID:26250048

  8. Retractorless surgery for a pineal region tumor through an occipital transtentorial approach.

    PubMed

    Nakao, Naoyuki

    2016-01-01

    This video demonstrates surgical techniques of the occipital transtentorial approach to a pineal region tumor without using a fixed brain retractor, which may cause functional impairment or even tissue injury to the occipital visual cortex. There are several ways to facilitate retractorless surgery through this approach. A lateral-semiprone positioning of the patient can induce gravity retraction. The brain is relaxed by draining CSF fluid through lumbar drainage or lateral ventricular tap in the case of obstructive hydrocephalus. Dynamic retraction with handheld instruments after extensive dissection of the deep venous system, including basal veins, can provide a sufficient working space. The video can be found here: https://youtu.be/kQvEHiNcRow . PMID:26722684

  9. [Occipital blindness in juvenile, spongiform glio-neuronal dystrophy (author's transl)].

    PubMed

    Schmidt, D; Noetzel, H; Mühlhäuser, J

    1977-10-01

    A 17-year-old patient with spongiform glioneuronal dystrophy is described. Symptoms of a severe infection at the onset of this disease give an insight on the unknown etiology. Occipital visual disturbances were the main signs in this case. 5 years after the onset of the disease death occured. The pathological-anatomical findings were: necrosis of ganglion cells in the visual cortex, severe loss of Purkinje- and granular cells of the cerebellum with spongy changes and cavities in the occipital lobe. Slight loss of ganglion cells was to be seen in the striata area, thalamus, dentate nucleus, and in the inferior olive. In addition, there was a demyelinisation of the posterior funiculi. PMID:592642

  10. Crystal structure of Homo sapiens protein LOC79017

    SciTech Connect

    Bae, Euiyoung; Bingman, Craig A.; Aceti, David J.; Phillips, Jr., George N.

    2010-02-08

    LOC79017 (MW 21.0 kDa, residues 1-188) was annotated as a hypothetical protein encoded by Homo sapiens chromosome 7 open reading frame 24. It was selected as a target by the Center for Eukaryotic Structural Genomics (CESG) because it did not share more than 30% sequence identity with any protein for which the three-dimensional structure is known. The biological function of the protein has not been established yet. Parts of LOC79017 were identified as members of uncharacterized Pfam families (residues 1-95 as PB006073 and residues 104-180 as PB031696). BLAST searches revealed homologues of LOC79017 in many eukaryotes, but none of them have been functionally characterized. Here, we report the crystal structure of H. sapiens protein LOC79017 (UniGene code Hs.530024, UniProt code O75223, CESG target number go.35223).

  11. Cervico-occipital joint (RX,CT)

    SciTech Connect

    Wackenheim, A.

    1985-01-01

    This book is a continuation of the author's Exercises in Radiological Diagnosis series. The text is organized into an atlas of 158 sets of images of normal anatomy and pathologic processes affecting the cervico-occipital junction, followed by comments, interpretations, and drawings in the second half of the book. The text includes a wide range of pathologic conditions extending from tumor to congenital variation.

  12. The timing of spheno-occipital fusion in hominoids.

    PubMed

    Balolia, Katharine L

    2015-01-01

    The degree of spheno-occipital fusion has been used to assign a relative age to dentally mature hominoid cranial specimens. However, a recent study of captive individuals (Poe: Am J Phys Anthropol 144 (2011) 162–165) concluded that fusion of the spheno-occipital suture in great ape taxa is of little utility for aging dentally mature individuals. In this contribution, I use dentally mature samples of extant hominoid taxa (Homo sapiens, Pan troglodytes schweinfurthii, Gorilla gorilla gorilla, Pongo pygmaeus pygmaeus and Hylobates lar) to investigate a) the temporal relationship between spheno-occipital fusion and dental maturity, b) whether there is an association between the degree of spheno-occipital fusion and relative age, c) whether there are differences in relative timing of spheno-occipital fusion between taxa, and d) whether there are sex differences in the relative timing of spheno-occipital fusion. Results suggest that a) a substantial proportion of dentally mature wild-shot chimpanzee, gorilla and orang-utans have unfused or partially fused spheno-occipital synchondoses, b) there is an association between the degree of spheno-occipital fusion and age, c) there are interspecific differences in the timing of spheno-occipital fusion, and d) there are significant sex differences in spheno-occipital fusion in chimpanzees, orang-utans and gibbons. Thus, contrary to previous work, degree of spheno-occipital fusion is a potentially useful indicator of relative maturity, especially in great ape taxa. PMID:25293964

  13. 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

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

    PubMed Central

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

    2013-01-01

    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

  15. The influence of posterior parietal cortex on extrastriate visual activity: A concurrent TMS and fast optical imaging study.

    PubMed

    Parks, Nathan A; Mazzi, Chiara; Tapia, Evelina; Savazzi, Silvia; Fabiani, Monica; Gratton, Gabriele; Beck, Diane M

    2015-11-01

    The posterior parietal cortex (PPC) is a critical node in attentional and saccadic eye movement networks of the cerebral cortex, exerting top-down control over activity in visual cortex. Here, we sought to further elucidate the properties of PPC feedback by providing a time-resolved map of functional connectivity between parietal and occipital cortex using single-pulse TMS to stimulate the left PPC while concurrently recording fast optical imaging data from bilateral occipital cortex. Magnetic stimulation of the PPC induced transient ipsilateral occipital activations (BA 18) 24-48ms post-TMS. Concurrent TMS and fast optical imaging results demonstrate a clear influence of PPC stimulation on activity within human extrastriate visual cortex and further extend this time- and space-resolved method for examining functional connectivity. PMID:26449990

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

    E-print Network

    Ottino, Julio M.

    management, strategy, leadership in for-profit and not-for- profit organizations, process improvement, training, health care management, instructional design, organization development and design, instructional, business, psychology, and law. Curriculum You must complete the following LOC concentration courses: · LOC

  17. [Panic attacks simulated by occipital lobe seizures].

    PubMed

    Stolle, Martin; Sieben, Claudia; Püst, Burkhard

    2009-05-01

    Eleven-year-old Stephanie was admitted to a child and adolescent psychiatry day hospital with symptoms of an anxiety and panic disorder, and compulsive and self-harmful behavior. The patient described detailed threatening scenic sequences that caused her to feel panicky. They symptoms could be classified as epilepsy with visually dominated seizures of the occipital lobe. In addition to pharmacological treatment with oxcabazepine, extensive multimodal interventions as part of the child and adolescent psychiatric day hospital treatment program helped all family members to understand and handle the seizures. Eight weeks after initiation of treatment, Stephanie was seizure-free. Complex partial epilepsy can be mistaken for primary child-psychiatric disorder. PMID:19415605

  18. ORIGINAL ARTICLE High refractive index of melanin in shiny occipital

    E-print Network

    ORIGINAL ARTICLE High refractive index of melanin in shiny occipital feathers of a bird of paradise by ordered melanin pigmentation. The barbules of the Parotia's occipital feathers, with thickness ,3 mm, contain 6­7 layers of densely packed melanin rodlets (diameter ,0.25 mm, length ,2 mm). The effectively ,0

  19. 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

  20. Demo Abstract: QiLoc--A Qi-Wireless Based Platform for Robust User-Initiated Indoor Location Services

    E-print Network

    Demo Abstract: QiLoc--A Qi-Wireless Based Platform for Robust User-Initiated Indoor Location and implementa- tion of a novel user-initiated indoor location system called QiLoc. QiLoc is a simple yet effective way to accurately lo- cate and identify occupants inside buildings. QiLoc is com- posed of Qi

  1. Tiny hair tuft: a clue for occipital cephalocele.

    PubMed

    Hatipoglu, Nevin; Türel, Ozden; Hatipoglu, Husem; Engerek, Nuri; Siraneci, Rengin

    2014-02-01

    Recurrent meningitis is a rare problem and can be due to alterations in immune system, or craniospinal defect. Any clue either in patient's history or physical examination would be helpful for avoiding unnecessary and tiring tests. Here we present the case of a child with recurrent bacterial meningitis who had an unnoticed hair tuft on the occipital region. The final diagnosis was occipital cephalocele with a rare presentation of a tiny tuft of hair. PMID:23982828

  2. Suppression of unformed visual hallucinations in homonymous hemianopia from occipital stroke using TMS.

    PubMed

    Rafique, Sara; Richards, John; Steeves, Jennifer

    2015-09-01

    Visual hallucinations represent the dissociation between visual perception and sensory input. We present the case of a 31-year old patient who perceived continuous unformed hallucinations in the hemianopic field immediately following right occipital cortex stroke, which have remained unchanged over 2 years. We performed 1 Hz repetitive transcranial magnetic stimulation (TMS) to the lesioned area for 30 minutes per day over 5 days in an attempt to suppress the perpetual hallucinations. fMRI was performed prior to and after TMS treatment to assess plasticity changes. Pre-TMS, the patient showed greater immediate activation at the boundary of the lesion compared to healthy controls; in the cuneus, lingual gyrus and surrounding areas. The associated "hyperactivity" corresponded to a reported perceptual increase in visual hallucinations. In addition, the patient displayed greater right frontal lobe activity compared to controls prior to TMS, indicative of a greater level of distress (Bartolic et al., 1999). During daily TMS sessions, the perception of hallucinations was greatly reduced. Post-TMS fMRI showed suppression of activity in the previously associated regions of "hyperactivity" to a level similar to that of controls. This is consistent with our previous work showing a decrease in occipital activation with TMS results in a decrease of frontal activity, thereby indicating connections between ventral regions and the frontal lobe (Rafique et al., 2014). Notably, the patient displayed greater activity post-TMS in the inferotemporal and parietal lobes when viewing images of objects and scenes respectively, demonstrating a redistribution of activity most likely regarding object and attention processing. This case provides evidence of an infarct resulting in excitatory discharges at the border of the lesioned area, which stimulate neighbouring areas, and thus results in abnormal visual perception. We causally demonstrate that repetitive TMS provides a valuable method of modulating hallucinations from occipital injury or infarct. Meeting abstract presented at VSS 2015. PMID:26326725

  3. 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

  4. Alexia Without Agraphia in a Right-Handed Individual Following Right Occipital Stroke.

    PubMed

    Robinson, Jordan S; Collins, Robert L; Mukhi, Shalini V

    2016-01-01

    Alexia without agraphia is a disconnection syndrome that typically involves damage to the occipital lobe, with splenium involvement, in the dominant left hemisphere. We describe an exceptionally rare case of a right-handed individual displaying this deficit following a right-sided occipital stroke. A report of a single case of a 65-year-old man is presented with data from appointments with the neurology and neuropsychology departments that occurred approximately 10 and 12 months following the patient's stroke. During the evaluation, he exhibited a marked deficit in his ability to read, with vision grossly intact. His ability to write single words and short phrases from dictation was intact, but he was later unable to read them. This case demonstrates the complexity of the organization of language in the human brain. Although a large majority of individuals exhibit language dominance in their left hemispheres, it remains possible that some right-handed individuals may show atypical organization of language. This highlights the need for clinicians to consider atypical cortical organization when observed deficits may not necessarily match expected lesions within the cortex. PMID:26397830

  5. 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

  6. 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 100 ms 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 200 ms 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

  7. SherLoc2: a high-accuracy hybrid method for predicting subcellular localization of proteins.

    PubMed

    Briesemeister, Sebastian; Blum, Torsten; Brady, Scott; Lam, Yin; Kohlbacher, Oliver; Shatkay, Hagit

    2009-11-01

    SherLoc2 is a comprehensive high-accuracy subcellular localization prediction system. It is applicable to animal, fungal, and plant proteins and covers all main eukaryotic subcellular locations. SherLoc2 integrates several sequence-based features as well as text-based features. In addition, we incorporate phylogenetic profiles and Gene Ontology (GO) terms derived from the protein sequence to considerably improve the prediction performance. SherLoc2 achieves an overall classification accuracy of up to 93% in 5-fold cross-validation. A novel feature, DiaLoc, allows users to manually provide their current background knowledge by describing a protein in a short abstract which is then used to improve the prediction. SherLoc2 is available both as a free Web service and as a stand-alone version at http://www-bs.informatik.uni-tuebingen.de/Services/SherLoc2. PMID:19764776

  8. Grievous Temporal and Occipital Injury Caused by a Bear Attack

    PubMed Central

    Thada, Nikhil Dinaker; Rao, Pallavi; Thada, Smitha Rani; Prasad, Kishore Chandra

    2013-01-01

    Bear attacks are reported from nearly every part of the world. The chance of a human encountering a bear increases as the remote bear territory diminishes. The sloth bear is one of the three species of bears found in India, which inhabits the forests of India and its neighboring countries. Here we describe a teenager who came to us with a critical injury involving the face, temporal and occipital bones inflicted by a sloth bear attack. He underwent a temporal exploration, facial nerve decompression, pinna reconstruction, and occipital bone repair to save him from fatality. PMID:24396623

  9. "What?" and "where?" versus "what is where?": the impact of task on coding of object form and position in the lateral occipital complex.

    PubMed

    Macevoy, Sean P

    2013-01-01

    Fast and accurate recognition of both the identities and positions of objects in visual space is critical to deciphering visual environments. Studies in both humans and nonhuman primates have demonstrated that neural populations in ventral temporal visual areas are jointly tuned to both the form and position of objects, allowing information about the identities of objects to be "tagged" with their positions. Because not all behaviors demand that the identities of objects be associated with position information with equal precision, however, the present study asked whether the spatial tuning of form-encoding populations in the human lateral occipital complex (LOC) is sculpted by task demands. Subjects were scanned using functional magnetic resonance imaging while viewing matches of the game Rock, Paper, Scissors played with exemplar pairs from those categories. Subjects first performed a repetition-detection task that depended on object form but not position; subsequently, subjects viewed the same stimuli while determining the position of each pair's "winner," a task that depended upon the conjunction of object form and position. Compared to data from the initial scan, multivoxel activity patterns evoked in the lateral occipital (LO) subdivision of LOC while subjects judged winners showed enhanced sensitivity to the relative positions of objects in pairs. Although superficially consistent with dynamic position tuning, this effect appears to be attributable to an accompanying task-dependent improvement in the sensitivity of LO populations to object form. The results thus suggest that the spatial tuning of form-encoding populations in LO does not depend upon the precision of spatial information demanded by a task. PMID:23873674

  10. 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

  11. 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

  12. Occipital Nerve Blocks for Pediatric Posttraumatic Headache: A Case Series.

    PubMed

    Seeger, Trevor A; Orr, Serena; Bodell, Lisa; Lockyer, Lisette; Rajapakse, Thilinie; Barlow, Karen M

    2015-08-01

    Posttraumatic headache is one of the most common and disabling symptoms after traumatic brain injury. However, evidence for treating posttraumatic headache is sparse, especially in the pediatric literature. This retrospective chart review evaluated the use of occipital nerve blocks in adolescents treated for posttraumatic headache following mild traumatic brain injury, presenting to the Complex Concussion and Traumatic Brain Injury clinic. Fifteen patients (mean age 15.47; range: 13-17) received occipital nerve block for posttraumatic headache. Follow-up was obtained in 14 patients at 5.57 (standard deviation = 3.52) months postinjury. The headache burden was high, with all except one having headaches 15 or more days per month (median 30, range 10-30). Sixty-four percent reported long-term response to the occipital nerve blocks, with associated improved quality of life and decreased postconcussion symptom scores (P < .05). One patient reported transient allopecia. Occipital nerve blocks are well tolerated and can be helpful in posttraumatic headache. PMID:25406154

  13. 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 with spontaneous EEG recor- ded. Meditation state dynamics were measured with spec- tral decomposition of the last

  14. RESEARCH REPORT Occipital gamma activation during Vipassana meditation

    E-print Network

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

  15. 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…

  16. QiLoc: A Qi Wireless Charging Based System for Robust User-Initiated Indoor Location Services

    E-print Network

    QiLoc: A Qi Wireless Charging Based System for Robust User-Initiated Indoor Location Services 1 the design and implementation of a novel user-initiated indoor localization system called QiLoc. QiLoc is a simple yet effective way to accurately locate and identify occupants of Qi-compatible devices inside

  17. Long non-coding RNA Loc554202 regulates proliferation and migration in breast cancer cells

    SciTech Connect

    Shi, Yongguo; Lu, Jianwei; Zhou, Jing; Tan, Xueming; He, Ye; Ding, Jie; Tian, Yun; Wang, Li; Wang, Keming

    2014-04-04

    Highlights: • First, we have shown that upregulated of the Loc554202 in breast cancer tissues. • Second, we demonstrated the function of Loc554202 in breast cancer cell. • Finally, we demonstrated that LOC554202 knockdown could inhibit tumor growth in vivo. - Abstract: Data derived from massive cloning and traditional sequencing methods have revealed that long non-coding RNAs (lncRNA) play important roles in the development and progression of cancer. Although many studies suggest that the lncRNAs have different cellular functions, many of them are not yet to be identified and characterized for the mechanism of their functions. To address this question, we assay the expression level of lncRNAs–Loc554202 in breast cancer tissues and find that Loc554202 is significantly increased compared with normal control, and associated with advanced pathologic stage and tumor size. Moreover, knockdown of Loc554202 decreased breast cancer cell proliferation, induced apoptosis and inhibits migration/invasion in vitro and impeded tumorigenesis in vivo. These data suggest an important role of Loc554202 in breast tumorigenesis.

  18. Location and Spatial Profile of Category-Specific Regions in Human Extrastriate Cortex

    E-print Network

    Kanwisher, Nancy

    Location and Spatial Profile of Category-Specific Regions in Human Extrastriate Cortex MonaMRI) 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

  19. 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…

  20. Traumatic atlanto-occipital dissociation presenting as locked-in syndrome.

    PubMed

    Desai, Rupen; Kinon, Merritt D; Loriaux, Daniel B; Bagley, Carlos A

    2015-12-01

    We present an unusual presentation of unstable atlanto-occipital dissociation as locked-in syndrome. Traumatic atlanto-occipital dissociation is a severe injury that accounts for 15-20% of all fatal cervical spinal injuries. A disruption occurs between the tectorial ligaments connecting the occipital condyle to the superior articulating facets of the atlas, resulting in anterior, longitudinal, or posterior translation, and it may be associated with Type III odontoid fractures. Furthermore, the dissociation may be complete (atlanto-occipital dislocation) or incomplete (atlanto-occipital subluxation), with neurologic findings ranging from normal to complete quadriplegia with respiratory compromise. PMID:26190221

  1. Brain Herniation in Neurofibromatosis with Dysplasia of Occipital Bone and Posterior Skull Base

    PubMed Central

    Rangarajan, Vithal; Mahore, Amit; Patil, Manoj; Sathe, Prashant; Kaswa, Amol; Gore, Sandeep; Dharurkar, Pralhad; Kawale, Juhi

    2015-01-01

    A 22-year-old female, a known case of neurofibromatosis 1 (NF1), presented with a congenital swelling in the left occipital region. She had developed recent onset dysphagia and localized occipital headache. Neuroradiology revealed a left occipital meningoencephalocele and a left parapharyngeal meningocele. This was associated with ventriculomegaly. She was advised on cranioplasty along with duraplasty which she denied. She agreed to a lumbar-peritoneal shunt. She described a dramatic improvement in her symptoms following the lumbar-peritoneal shunt. Occipital dysplasias, though uncommon, have been reported in the literature. We review this case and its management and discuss relevant literature on occipital dysplasias in NF1. PMID:26600957

  2. The human cerebral cortex is neither one nor many: neuronal distribution reveals two quantitatively different zones in the gray matter, three in the white matter, and explains local variations in cortical folding.

    PubMed

    Ribeiro, Pedro F M; Ventura-Antunes, Lissa; Gabi, Mariana; Mota, Bruno; Grinberg, Lea T; Farfel, José M; Ferretti-Rebustini, Renata E L; Leite, Renata E P; Filho, Wilson J; Herculano-Houzel, Suzana

    2013-01-01

    The human prefrontal cortex has been considered different in several aspects and relatively enlarged compared to the rest of the cortical areas. Here we determine whether the white and gray matter of the prefrontal portion of the human cerebral cortex have similar or different cellular compositions relative to the rest of the cortical regions by applying the Isotropic Fractionator to analyze the distribution of neurons along the entire anteroposterior axis of the cortex, and its relationship with the degree of gyrification, number of neurons under the cortical surface, and other parameters. The prefrontal region shares with the remainder of the cerebral cortex (except for occipital cortex) the same relationship between cortical volume and number of neurons. In contrast, both occipital and prefrontal areas vary from other cortical areas in their connectivity through the white matter, with a systematic reduction of cortical connectivity through the white matter and an increase of the mean axon caliber along the anteroposterior axis. These two parameters explain local differences in the distribution of neurons underneath the cortical surface. We also show that local variations in cortical folding are neither a function of local numbers of neurons nor of cortical thickness, but correlate with properties of the white matter, and are best explained by the folding of the white matter surface. Our results suggest that the human cerebral cortex is divided in two zones (occipital and non-occipital) that differ in how neurons are distributed across their gray matter volume and in three zones (prefrontal, occipital, and non-occipital) that differ in how neurons are connected through the white matter. Thus, the human prefrontal cortex has the largest fraction of neuronal connectivity through the white matter and the smallest average axonal caliber in the white matter within the cortex, although its neuronal composition fits the pattern found for other, non-occipital areas. PMID:24032005

  3. The human cerebral cortex is neither one nor many: neuronal distribution reveals two quantitatively different zones in the gray matter, three in the white matter, and explains local variations in cortical folding

    PubMed Central

    Ribeiro, Pedro F. M.; Ventura-Antunes, Lissa; Gabi, Mariana; Mota, Bruno; Grinberg, Lea T.; Farfel, José M.; Ferretti-Rebustini, Renata E. L.; Leite, Renata E. P.; Filho, Wilson J.; Herculano-Houzel, Suzana

    2013-01-01

    The human prefrontal cortex has been considered different in several aspects and relatively enlarged compared to the rest of the cortical areas. Here we determine whether the white and gray matter of the prefrontal portion of the human cerebral cortex have similar or different cellular compositions relative to the rest of the cortical regions by applying the Isotropic Fractionator to analyze the distribution of neurons along the entire anteroposterior axis of the cortex, and its relationship with the degree of gyrification, number of neurons under the cortical surface, and other parameters. The prefrontal region shares with the remainder of the cerebral cortex (except for occipital cortex) the same relationship between cortical volume and number of neurons. In contrast, both occipital and prefrontal areas vary from other cortical areas in their connectivity through the white matter, with a systematic reduction of cortical connectivity through the white matter and an increase of the mean axon caliber along the anteroposterior axis. These two parameters explain local differences in the distribution of neurons underneath the cortical surface. We also show that local variations in cortical folding are neither a function of local numbers of neurons nor of cortical thickness, but correlate with properties of the white matter, and are best explained by the folding of the white matter surface. Our results suggest that the human cerebral cortex is divided in two zones (occipital and non-occipital) that differ in how neurons are distributed across their gray matter volume and in three zones (prefrontal, occipital, and non-occipital) that differ in how neurons are connected through the white matter. Thus, the human prefrontal cortex has the largest fraction of neuronal connectivity through the white matter and the smallest average axonal caliber in the white matter within the cortex, although its neuronal composition fits the pattern found for other, non-occipital areas. PMID:24032005

  4. Temporal stability of visually selective responses in intracranial field potentials recorded from human occipital and temporal lobes

    PubMed Central

    Bansal, Arjun K.; Singer, Jedediah M.; Anderson, William S.; Golby, Alexandra; Madsen, Joseph R.

    2012-01-01

    The cerebral cortex needs to maintain information for long time periods while at the same time being capable of learning and adapting to changes. The degree of stability of physiological signals in the human brain in response to external stimuli over temporal scales spanning hours to days remains unclear. Here, we quantitatively assessed the stability across sessions of visually selective intracranial field potentials (IFPs) elicited by brief flashes of visual stimuli presented to 27 subjects. The interval between sessions ranged from hours to multiple days. We considered electrodes that showed robust visual selectivity to different shapes; these electrodes were typically located in the inferior occipital gyrus, the inferior temporal cortex, and the fusiform gyrus. We found that IFP responses showed a strong degree of stability across sessions. This stability was evident in averaged responses as well as single-trial decoding analyses, at the image exemplar level as well as at the category level, across different parts of visual cortex, and for three different visual recognition tasks. These results establish a quantitative evaluation of the degree of stationarity of visually selective IFP responses within and across sessions and provide a baseline for studies of cortical plasticity and for the development of brain-machine interfaces. PMID:22956795

  5. Traumatic aneurysm of the occipital artery secondary to paintball injury.

    PubMed

    John, Neely; Leach, James L; Rachana, Tyagi; Mangano, Francesco T

    2009-01-01

    Paintball is an "extreme sport" that has been steadily growing in popularity since the early 1980s. Although this activity is considered recreational, there are a number of inherent dangers associated. Most notably, the number of head and neck injuries due to paintball participation has been increasing in recent years. In this paper we present the first reported case of occipital artery traumatic pseudoaneurysm resulting from a paintball accident. The presentation, diagnosis and intraoperative findings are detailed. A discussion including a review of the literature is also presented. The authors recommend a re-evaluation of guidelines within the paintball sporting industry, including improvements in protective equipment. PMID:18922630

  6. The antidepressant effect of ketamine is not associated with changes in occipital amino acid neurotransmitter content as measured by [(1)H]-MRS.

    PubMed

    Valentine, Gerald W; Mason, Graeme F; Gomez, Rosane; Fasula, Madonna; Watzl, June; Pittman, Brian; Krystal, John H; Sanacora, Gerard

    2011-02-28

    The NMDA receptor antagonist ketamine can induce a rapid improvement in depressive symptoms that often endures for days after a single intravenous dose. The pharmacodynamic basis for this effect is poorly understood. Using a proton magnetic resonance spectroscopy ([(1)H]-MRS) method that previously detected a normalization of amino acid neurotransmitter (AANt) content after chronic treatment with conventional antidepressant treatments, we examined whether the acute action of ketamine is associated with alterations in AANt content as well. Ten subjects with major depressive disorder (MDD) received saline, then ketamine in a fixed order, one week apart, under single-blind conditions. Each infusion was associated with three [(1)H] MRS scans (baseline, 3h and 48 h post-infusion) that measured glutamate, GABA and glutamine within the occipital cortex. Rating scales were administered before, during and after each infusion. The rapid (1h) and sustained (at least 7 days) antidepressant effect we observed after ketamine infusion was not associated with either baseline measures of, or changes in, occipital AANt content. Dissociative symptoms were not correlated with changes in depression scores. While our results indicate that changes in occipital AANt content are not a correlate of ketamine's antidepressant action, this may only apply to the regional and temporal windows of our MRS measurements. PMID:21232924

  7. Airbag-mediated pediatric atlanto-occipital dislocation.

    PubMed

    Saveika, Joseph A; Thorogood, Christine

    2006-12-01

    Pediatric atlanto-occipital dislocation (AOD) most commonly occurs in victims of high-velocity motor vehicle collisions and usually results in death. The mechanical and anatomic predisposing factors for AOD in children have been well documented. With the introduction of passenger-side air bags in automobiles, reports have documented an increased incidence of pediatric cervical spine injuries, including AOD, in low-speed motor vehicle collisions. Although long-term survival in AOD is so unusual that there is no separate literature regarding its physiatric treatment, it is generally treated like any other high cervical spinal cord injury. Recent advances in adaptive technology have aided greatly in management. Despite benefits that adaptive technology affords, the best treatment for AOD is still prevention. For this reason, children under the age of 13 should be restrained backseat passengers in automobiles. PMID:17117005

  8. The Role of Transverse Occipital Sulcus in Scene Perception and Its Relationship to Object Individuation in

    E-print Network

    Xu, Yaoda

    The Role of Transverse Occipital Sulcus in Scene Perception and Its Relationship to Object Individuation in Inferior Intraparietal Sulcus Katherine C. Bettencourt and Yaoda Xu Abstract The parietal these areas relate to each other. Two such regions are the transverse occipital sulcus (TOS) scene area

  9. Occipital lymph node metastasis from nasopharyngeal carcinoma: a special case report and literature review.

    PubMed

    Yang, Jing; Xia, Wei-Xiong; Xiang, Yan-Qun; Lv, Xing; Ke, Liang-Ru; Yu, Ya-Hui; Guo, Xiang

    2016-01-01

    Cervical lymph node metastasis is common in patients with nasopharyngeal carcinoma (NPC), but occipital lymph node metastasis in NPC patients has not yet been reported. In this case report, we describe an NPC patient with occipital lymph node metastasis. The clinical presentation, diagnostic procedure, treatment, and outcome of this case were presented, with a review of the related literature. PMID:26728009

  10. 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

  11. Target sites for transcallosal fibers in human visual cortex - A combined diffusion and polarized light imaging study.

    PubMed

    Caspers, Svenja; Axer, Markus; Caspers, Julian; Jockwitz, Christiane; Jütten, Kerstin; Reckfort, Julia; Grässel, David; Amunts, Katrin; Zilles, Karl

    2015-11-01

    Transcallosal fibers of the visual system have preferential target sites within the occipital cortex of monkeys. These target sites coincide with vertical meridian representations of the visual field at borders of retinotopically defined visual areas. The existence of preferential target sites of transcallosal fibers in the human brain at the borders of early visual areas was claimed, but controversially discussed. Hence, we studied the distribution of transcallosal fibers in human visual cortex, searching for an organizational principle across early and higher visual areas. In-vivo high angular resolution diffusion imaging data of 28 subjects were used for probabilistic fiber tracking using a constrained spherical deconvolution approach. The fiber architecture within the target sites was analyzed at microscopic resolution using 3D polarized light imaging in a post-mortem human hemisphere. Fibers through a seed in the splenium of the corpus callosum reached the occipital cortex via the forceps major and the tapetum. We found target sites of these transcallosal fibers at borders of cytoarchitectonically defined occipital areas not only between early visual areas V1 and V2, V3d and V3A, and V3v and V4, but also between higher extrastriate areas, namely V4 (ventral) and posterior fusiform area FG1 as well as posterior fusiform area FG2 and lateral occipital cortex. In early visual areas, the target sites coincided with the vertical meridian representations of retinotopic maps. The spatial arrangement of the fibers in the 'border tuft' region at the V1/V2 border was found to be more complex than previously observed in myeloarchitectonic studies. In higher visual areas, our results provided additional evidence for a hemi-field representation in human area V4. The fiber topography in posterior fusiform gyrus indicated that additional retinotopic areas might exist, located between the recently identified retinotopic representations phPITv/phPITd and PHC-1/PHC-2 in lateral occipital cortex and parahippocampal gyrus. PMID:25697048

  12. Credit Card Misuse, Money Attitudes, and Compulsive Buying Behaviors: A Comparison of Internal and External Locus of Control (LOC) Consumers

    ERIC Educational Resources Information Center

    Watson, Stevie

    2009-01-01

    This study examined attitudinal and behavioral differences between internal and external locus of control (LOC) consumers on credit card misuse, the importance of money, and compulsive buying. Using multiple analysis of variance and separate analyses of variance, internal LOC consumers were found to have lower scores on credit card misuse and…

  13. Sensitivity to syntax in visual cortex

    PubMed Central

    Dikker, Suzanne; Rabagliati, Hugh; Pylkkänen, Liina

    2009-01-01

    One of the most intriguing findings on language comprehension is that violations of syntactic predictions can affect event-related potentials as early as 120 ms, in the same time-window as early sensory processing. This effect, the so-called early left-anterior negativity (ELAN), has been argued to reflect word category access and initial syntactic structure building (Friederici, 2002). In two experiments, we used magnetoencephalography to investigate whether (a) rapid word category identification relies on overt category-marking closed-class morphemes and (b) whether violations of word category predictions affect modality-specific sensory responses. Participants read sentences containing violations of word category predictions. Unexpected items varied in whether or not their word category was marked by an overt function morpheme. In Experiment 1, the amplitude of the visual evoked M100 component was increased for unexpected items, but only when word category was overtly marked by a function morpheme. Dipole modeling localized the generator of this effect to the occipital cortex. Experiment 2 replicated the main results of Experiment 1 and eliminated two non-morphology-related explanations of the M100 contrast we observed between targets containing overt category-marking and targets that lacked such morphology. Our results show that during reading, syntactically relevant cues in the input can affect activity in occipital regions at around 125 ms, a finding that may shed new light on the remarkable rapidity of language processing. PMID:19121826

  14. Pre-cue Fronto-Occipital Alpha Phase and Distributed Cortical Oscillations Predict Failures of Cognitive Control

    PubMed Central

    Hamm, Jordan P.; Dyckman, Kara A.; McDowell, Jennifer E.; Clementz, Brett A.

    2012-01-01

    Cognitive control is required for correct performance on antisaccade tasks, including the ability to inhibit an externally driven ocular motor repsonse (a saccade to a peripheral stimulus) in favor of an internally driven ocular motor goal (a saccade directed away from a peripheral stimulus). Healthy humans occasionally produce errors during antisaccade tasks, but the mechanisms associated with such failures of cognitive control are uncertain. Most research on cognitive control failures focuses on post-stimulus processing, although a growing body of literature highlights a role of intrinsic brain activity in perceptual and cognitive performance. The current investigation used dense array electroencephalography and distributed source analyses to examine brain oscillations across a wide frequency bandwidth in the period prior to antisaccade cue onset. Results highlight four important aspects of ongoing and preparatory brain activations that differentiate error from correct antisaccade trials: (i) ongoing oscillatory beta (20–30Hz) power in anterior cingulate prior to trial initiation (lower for error trials), (ii) instantaneous phase of ongoing alpha-theta (7Hz) in frontal and occipital cortices immediately before trial initiation (opposite between trial types), (iii) gamma power (35–60Hz) in posterior parietal cortex 100 ms prior to cue onset (greater for error trials), and (iv) phase locking of alpha (5–12Hz) in parietal and occipital cortices immediately prior to cue onset (lower for error trials). These findings extend recently reported effects of pre-trial alpha phase on perception to cognitive control processes, and help identify the cortical generators of such phase effects. PMID:22593071

  15. PiLoc: a Self-Calibrating Participatory Indoor Localization System

    E-print Network

    Chan, Mun Choon

    , Participatory, Smart- phones, Floor Plan I. INTRODUCTION Location is one of the most important context imposed by the walking trajectory of the user and the floor plan. There are also approaches that try, all these approaches [1], [3], [12], [13] require knowledge of the floor plan. UnLoc [2] attempts

  16. Algorithmic, LOCS and HOCS (Chemistry) Exam Questions: Performance and Attitudes of College Students.

    ERIC Educational Resources Information Center

    Zoller, Uri

    2002-01-01

    Studies the performance of freshmen biology and physics-mathematics majors and chemistry majors as well as pre- and in-service chemistry teachers at two Israeli universities on algorithmic (ALG), lower-order cognitive skills (LOCS), and higher-order cognitive skills (HOCS) chemistry exam questions. Finds that students in both universities…

  17. Reorganization of Retinotopic Maps After Occipital Lobe Infarction

    PubMed Central

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

    2015-01-01

    We studied patient JS who had a right occipital infarct that encroached on visual areas V1, V2v and VP. When tested psychophysically, he was very impaired at detecting the direction of motion in random dot displays where a variable proportion of dots moving in one direction (signal) were embedded in masking motion noise (noise dots). The impairment on this Motion Coherence task was especially marked when the display was presented to the upper left (affected) visual quadrant, contralateral to his lesion. However, with extensive training, by 11 months his threshold fell to the level of healthy subjects. Training on the Motion Coherence task generalized to another motion task, the Motion Discontinuity task, on which he had to detect the presence of an edge that was defined by the difference in the direction of the coherently moving dots (signal) within the display. He was much better at this task at 8 than 3 months, and this improvement was associated with an increase in the activation of the human MT complex (hMT+) and in the kinetic occipital region (KO) as shown by repeated fMRI scans. We also used fMRI to perform retinotopic mapping at 3, 8 and 11 months after the infarct. We quantified the retinotopy and areal shifts by measuring the distances between the center of mass of functionally defined areas, computed in spherical surface-based coordinates. The functionally defined retinotopic areas V1, V2v, V2d and VP were initially smaller in the lesioned right hemisphere, but they increased in size between 3 and 11 months. This change was not found in the normal, left hemisphere, of the patient or in either hemispheres of the healthy control subjects. We were interested in whether practice on the motion coherence task promoted the changes in the retinotopic maps. We compared the results for patient JS with those from another patient (PF) who had a comparable lesion but had not been given such practice. We found similar changes in the maps in the lesioned hemisphere of PF. However, PF was only scanned at 3 and 7 months, and the biggest shifts in patient JS were found between 8 and 11 months. Thus, it is important to carry out a prospective study with a trained and untrained group so as to determine whether the patterns of reorganization that we have observed can be further promoted by training. PMID:24345177

  18. ngLOC: software and web server for predicting protein subcellular localization in prokaryotes and eukaryotes

    PubMed Central

    2012-01-01

    Background Understanding protein subcellular localization is a necessary component toward understanding the overall function of a protein. Numerous computational methods have been published over the past decade, with varying degrees of success. Despite the large number of published methods in this area, only a small fraction of them are available for researchers to use in their own studies. Of those that are available, many are limited by predicting only a small number of organelles in the cell. Additionally, the majority of methods predict only a single location for a sequence, even though it is known that a large fraction of the proteins in eukaryotic species shuttle between locations to carry out their function. Findings We present a software package and a web server for predicting the subcellular localization of protein sequences based on the ngLOC method. ngLOC is an n-gram-based Bayesian classifier that predicts subcellular localization of proteins both in prokaryotes and eukaryotes. The overall prediction accuracy varies from 89.8% to 91.4% across species. This program can predict 11 distinct locations each in plant and animal species. ngLOC also predicts 4 and 5 distinct locations on gram-positive and gram-negative bacterial datasets, respectively. Conclusions ngLOC is a generic method that can be trained by data from a variety of species or classes for predicting protein subcellular localization. The standalone software is freely available for academic use under GNU GPL, and the ngLOC web server is also accessible at http://ngloc.unmc.edu. PMID:22780965

  19. 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. PMID:26167209

  20. The course of the greater occipital nerve in the suboccipital region: a proposal for setting landmarks for local anesthesia in patients with occipital neuralgia.

    PubMed

    Natsis, K; Baraliakos, X; Appell, H J; Tsikaras, P; Gigis, I; Koebke, J

    2006-05-01

    The anatomical relationships of the greater occipital nerve (GON) to the semispinalis capitis muscle (SCM) and the trapezius muscle aponeurosis (TMA) were examined to identify topographic landmarks for use in anesthetic blockade of the GON in occipital neuralgia. The course and the diameter of the GON were studied in 40 cadavers (29 females, 11 males), and the points where it pierced the SCM and the TMA were identified. The course of the GON did not differ between males and females. A left-right difference was detected in the site of the GON in the TMA region but not in the SCM region. The nerve became wider towards the periphery. This may be relevant to entrapment of the nerve in the development of occipital neuralgia. In three cases, the GON split into two branches before piercing the TMA and reunited after having passed the TMA, and it pierced the obliquus capitis inferior muscle in another three cases. The GON and the lesser occipital nerve reunited at the level of the occiput in 80% of the specimens. The occiput and the nuchal midline are useful topographic landmarks to guide anesthetic blockade of the GON for diagnosis and therapy of occipital neuralgia. The infiltration is probably best aimed at the site where the SCM is pierced by the GON. PMID:16258972

  1. 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

  2. [Multiple bladder diverticula caused by occipital horn syndrome].

    PubMed

    Legros, L; Revencu, N; Nassogne, M-C; Wese, F-X; Feyaerts, A

    2015-11-01

    We report on the case of a child who presented with recurrent, multiple, and voluminous bladder diverticula. Bladder diverticula are defined as a herniation of the mucosa through the bladder muscle or the detrusor. Causes are numerous and diverticula can be classified into primary congenital diverticula (para-ureteral - or Hutch diverticula - and posterolateral diverticula); secondary diverticula (resulting from chronic mechanical obstruction or from neurological disease; and diverticula secondary to connective tissue or muscle fragility. The latter is seen in disease entities such as prune belly syndrome, Ehlers-Danlos syndrome, cutis laxa syndrome, OHS (occipital horn syndrome), Menkes disease, and Williams-Beuren syndrome. In this patient, the cause of these diverticula was OHS, a genetic, recessive X-chromosome-linked syndrome, responsible for abnormal tissue caused by a disorder in copper metabolism. This case reminds us of the importance of pushing the diagnostic workup when presented with multiple and/or large bladder diverticula, and in particular to search for rare malformation syndromes after exclusion of an obstacle. PMID:26386812

  3. 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

  4. Randomized, double-blind, comparative-effectiveness study comparing pulsed radiofrequency to steroid injections for occipital neuralgia or migraine with occipital nerve tenderness

    PubMed Central

    Cohen, Steven P.; Peterlin, B. Lee; Fulton, Larry; Neely, Edward T.; Kurihara, Connie; Gupta, Anita; Mali, Jimmy; Fu, Diana C.; Jacobs, Michael B.; Plunkett, Anthony R.; Verdun, Aubrey J.; Stojanovic, Milan P.; Hanling, Steven; Constantinescu, Octav; White, Ronald L.; McLean, Brian C.; Pasquina, Paul F.; Zhao, Zirong

    2015-01-01

    Occipital neuralgia (ON) is characterized by lancinating pain and tenderness overlying the occipital nerves. Both steroid injections and pulsed radiofrequency (PRF) are used to treat ON, but few clinical trials have evaluated efficacy, and no study has compared treatments. We performed a multicenter, randomized, double-blind, comparative-effectiveness study in 81 participants with ON or migraine with occipital nerve tenderness whose aim was to determine which treatment is superior. Forty-two participants were randomized to receive local anesthetic and saline, and three 120 second cycles of PRF per targeted nerve, and 39 were randomized to receive local anesthetic mixed with deposteroid and 3 rounds of sham PRF. Patients, treating physicians, and evaluators were blinded to interventions. The PRF group experienced a greater reduction in the primary outcome measure, average occipital pain at 6 weeks (mean change from baseline ?2.743 ± 2.487 vs ?1.377 ± 1.970; P <0.001), than the steroid group, which persisted through the 6-month follow-up. Comparable benefits favoring PRF were obtained for worst occipital pain through 3 months (mean change from baseline?1.925 ± 3.204 vs?0.541 ± 2.644; P = 0.043), and average overall headache pain through 6 weeks (mean change from baseline ?2.738 ± 2.753 vs ?1.120 ± 2.1; P = 0.037). Adverse events were similar between groups, and few significant differences were noted for nonpain outcomes. We conclude that although PRF can provide greater pain relief for ON and migraine with occipital nerve tenderness than steroid injections, the superior analgesia may not be accompanied by comparable improvement on other outcome measures. PMID:26447705

  5. Randomized, double-blind, comparative-effectiveness study comparing pulsed radiofrequency to steroid injections for occipital neuralgia or migraine with occipital nerve tenderness.

    PubMed

    Cohen, Steven P; Peterlin, B Lee; Fulton, Larry; Neely, Edward T; Kurihara, Connie; Gupta, Anita; Mali, Jimmy; Fu, Diana C; Jacobs, Michael B; Plunkett, Anthony R; Verdun, Aubrey J; Stojanovic, Milan P; Hanling, Steven; Constantinescu, Octav; White, Ronald L; McLean, Brian C; Pasquina, Paul F; Zhao, Zirong

    2015-12-01

    Occipital neuralgia (ON) is characterized by lancinating pain and tenderness overlying the occipital nerves. Both steroid injections and pulsed radiofrequency (PRF) are used to treat ON, but few clinical trials have evaluated efficacy, and no study has compared treatments. We performed a multicenter, randomized, double-blind, comparative-effectiveness study in 81 participants with ON or migraine with occipital nerve tenderness whose aim was to determine which treatment is superior. Forty-two participants were randomized to receive local anesthetic and saline, and three 120 second cycles of PRF per targeted nerve, and 39 were randomized to receive local anesthetic mixed with deposteroid and 3 rounds of sham PRF. Patients, treating physicians, and evaluators were blinded to interventions. The PRF group experienced a greater reduction in the primary outcome measure, average occipital pain at 6 weeks (mean change from baseline -2.743 ± 2.487 vs -1.377 ± 1.970; P < 0.001), than the steroid group, which persisted through the 6-month follow-up. Comparable benefits favoring PRF were obtained for worst occipital pain through 3 months (mean change from baseline -1.925 ± 3.204 vs -0.541 ± 2.644; P = 0.043), and average overall headache pain through 6 weeks (mean change from baseline -2.738 ± 2.753 vs -1.120 ± 2.1; P = 0.037). Adverse events were similar between groups, and few significant differences were noted for nonpain outcomes. We conclude that although PRF can provide greater pain relief for ON and migraine with occipital nerve tenderness than steroid injections, the superior analgesia may not be accompanied by comparable improvement on other outcome measures. PMID:26447705

  6. Neuropsychologia xxx (2004) xxxxxx Segregation and persistence of form in the lateral occipital complex

    E-print Network

    Vilis, Tutis

    2004-01-01

    Neuropsychologia xxx (2004) xxx­xxx Segregation and persistence of form in the lateral occipital.neuropsychologia.2004.06.020 #12;2 S. Ferber et al. / Neuropsychologia xxx (2004) xxx­xxx in this area regardless

  7. Ventral fixation of chronic atlanto-occipital luxation in a dog.

    PubMed

    Buks, Y; Snelling, S R; Yates, G D

    2011-09-01

    A 4·5-year-old male Australian Kelpie was presented for evaluation of ambulatory tetraparesis and neck pain of five weeks duration. Atlanto-occipital luxation was diagnosed by computed tomography. The joint was unstable following closed reduction, and a ventral surgical approach to the cranial cervical spine and occiput permitted manual reduction and stabilisation of the atlanto-occipital joint. The thickened joint capsule and articular cartilage were removed to promote AO arthrodesis. Eight cortical screws, inserted into the occipital condyles and C1, were embedded in polymethylmethacrylate to stabilise the atlanto-occipital articulation. The dog recovered uneventfully after it was placed in a neck brace and rested for six weeks. Neurologic examination at six weeks was normal and the dog returned to normal farm work 12 weeks after surgery. PMID:21824148

  8. Occipital somites guide motor axons of the accessory nerve in the avian embryo.

    PubMed

    Pu, Q; Bai, Z; Haque, Z; Wang, J; Huang, R

    2013-08-29

    The accessory nerve (nervus accessorius) displays a unique organization in that its axons ascend along the rostrocaudal axis after exiting the cervical spinal cord and medulla oblongata and thereafter project ventrally into the periphery at the first somite level. Little is known about how this organization is achieved. We have investigated the role of somites in the guidance of motor axons of the accessory nerve using heterotopic transplantations of somites in avian embryos. The formation of not only accessory nerve but also the vagal nerve was affected, when a more caudal occipital somite (somites 2-4) was grafted to the position of the first occipital somite. Our study reveals that only the first occipital somite permits the development of ventral projection of accessory axons, a process that is inhibited by more caudal occipital somites. PMID:23632169

  9. Changes in Cerebral Cortex of Children Treated for Medulloblastoma

    SciTech Connect

    Liu, Arthur K. . E-mail: aliu1@partners.org; Marcus, Karen J.; Fischl, Bruce; Grant, P. Ellen; Young Poussaint, Tina; Rivkin, Michael J.; Davis, Peter; Tarbell, Nancy J.; Yock, Torunn I.

    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.

  10. Widespread reduction of somatostatin-like immunoreactivity in the cerebral cortex in Alzheimer's disease.

    PubMed

    Beal, M F; Mazurek, M F; Svendsen, C N; Bird, E D; Martin, J B

    1986-10-01

    Although several studies have documented reduced concentrations of somatostatin-like immunoreactivity (SLI) in the cerebral cortex in Alzheimer's disease, there is controversy concerning the extent and importance of these changes. We measured SLI in brains obtained post mortem from 12 patients with pathologically confirmed Alzheimer's disease and from 13 neurologically normal controls. All major cortical and subcortical regions were examined. Widespread reductions of SLI in Alzheimer's disease cerebral cortex were found, with the most profound changes seen in temporal lobe; but there also were major reductions in both the frontal and occipital cortex. There were no significant reductions in subcortical regions. Characterization of SLI by high-pressure liquid chromatography showed no significant difference in profiles between Alzheimer's disease and control frontal cortex. These results suggest that the reduction in somatostatin immunoreactivity in Alzheimer's disease may be caused by degeneration of intrinsic somatostatin cortical neurons. PMID:3789664

  11. Neuropeptide Y immunoreactivity is reduced in cerebral cortex in Alzheimer's disease.

    PubMed

    Beal, M F; Mazurek, M F; Chattha, G K; Svendsen, C N; Bird, E D; Martin, J B

    1986-09-01

    Neuropeptide Y is a 36-amino acid peptide that is found in high concentrations in cerebral cortex and is contained in cortical neurons. We measured concentrations of this peptide in postmortem tissue from patients with Alzheimer's disease and controls using a sensitive and specific radioimmunoassay. High-performance liquid chromatography showed that more than 95% of immunoreactivity co-migrated with synthetic standards in both Alzheimer's disease and control frontal cortex. Significant reductions in neuropeptide Y-like immunoreactivity were found in eleven cortical regions, the hippocampus, and the locus ceruleus. The regions particularly affected included the temporal lobe, frontal lobe, and occipital cortex. As neuropeptide Y is co-localized with somatostatin in a considerable proportion of cortical neurons, the loss of immunoreactivity may in part reflect degeneration of these neurons. Further study of the selective vulnerability of these neurons in Alzheimer's disease cortex may provide clues to the nature of the underlying disease process. PMID:3767313

  12. How the cortico-thalamic feedback affects the EEG power spectrum over frontal and occipital regions during propofol-induced sedation.

    PubMed

    Hashemi, Meysam; Hutt, Axel; Sleigh, Jamie

    2015-10-01

    Increasing concentrations of the anaesthetic agent propofol initially induces sedation before achieving full general anaesthesia. During this state of anaesthesia, the observed specific changes in electroencephalographic (EEG) rhythms comprise increased activity in the ?- (0.5-4 Hz) and ?- (8-13 Hz) frequency bands over the frontal region, but increased ?- and decreased ?-activity over the occipital region. It is known that the cortex, the thalamus, and the thalamo-cortical feedback loop contribute to some degree to the propofol-induced changes in the EEG power spectrum. However the precise role of each structure to the dynamics of the EEG is unknown. In this paper we apply a thalamo-cortical neuronal population model to reproduce the power spectrum changes in EEG during propofol-induced anaesthesia sedation. The model reproduces the power spectrum features observed experimentally both in frontal and occipital electrodes. Moreover, a detailed analysis of the model indicates the importance of multiple resting states in brain activity. The work suggests that the ?-activity originates from the cortico-thalamic relay interaction, whereas the emergence of ?-activity results from the full cortico-reticular-relay-cortical feedback loop with a prominent enforced thalamic reticular-relay interaction. This model suggests an important role for synaptic GABAergic receptors at relay neurons and, more generally, for the thalamus in the generation of both the ?- and the ?- EEG patterns that are seen during propofol anaesthesia sedation. PMID:26256583

  13. Fabrication and testing of a PDMS multi-stacked hand-operated LOC for use in portable immunosensing systems.

    PubMed

    Park, Sin Wook; Lee, Jun Hwang; Yoon, Hyun C; Kim, Byung Woo; Sim, Sang Jun; Chae, Heeyeop; Yang, Sang Sik

    2008-12-01

    This paper presents the development of a reliable multi-liquid lab-on-a-chip (LOC), with a hand-operated mechanism, for the application in portable immunosensing systems. To control the transport of multiple liquids without any external equipment, we utilize capillary attraction force for filling and surface tension for stopping liquid flow. As a driving force, hydraulic pressure caused by the elastic deformation of a liquid reservoir transfers liquid stopped at passive valves. The proposed LOC successfully demonstrates a reliable sequential liquid transfer within the reaction channel. To highlight its feasibility as a portable diagnostic system, we performed the electrochemical immunoassay measuring antibody concentrations within the fabricated LOC. As a test biorecognition reaction, the anti-dinitrophenyl (DNP) antibody with an enzymatic catalysis was selected as the target analyte. The amplified signals obtained from this experiment indicated a high selectivity of the immunosensing LOC. PMID:18553169

  14. Faciotopy-A face-feature map with face-like topology in the human occipital face area.

    PubMed

    Henriksson, Linda; Mur, Marieke; Kriegeskorte, Nikolaus

    2015-11-01

    The occipital face area (OFA) and fusiform face area (FFA) are brain regions thought to be specialized for face perception. However, their intrinsic functional organization and status as cortical areas with well-defined boundaries remains unclear. Here we test these regions for "faciotopy", a particular hypothesis about their intrinsic functional organisation. A faciotopic area would contain a face-feature map on the cortical surface, where cortical patches represent face features and neighbouring patches represent features that are physically neighbouring in a face. The faciotopy hypothesis is motivated by the idea that face regions might develop from a retinotopic protomap and acquire their selectivity for face features through natural visual experience. Faces have a prototypical configuration of features, are usually perceived in a canonical upright orientation, and are frequently fixated in particular locations. To test the faciotopy hypothesis, we presented images of isolated face features at fixation to subjects during functional magnetic resonance imaging. The responses in V1 were best explained by low-level image properties of the stimuli. OFA, and to a lesser degree FFA, showed evidence for faciotopic organization. When a single patch of cortex was estimated for each face feature, the cortical distances between the feature patches reflected the physical distance between the features in a face. Faciotopy would be the first example, to our knowledge, of a cortical map reflecting the topology, not of a part of the organism itself (its retina in retinotopy, its body in somatotopy), but of an external object of particular perceptual significance. PMID:26235800

  15. Faciotopy—A face-feature map with face-like topology in the human occipital face area

    PubMed Central

    Henriksson, Linda; Mur, Marieke; Kriegeskorte, Nikolaus

    2015-01-01

    The occipital face area (OFA) and fusiform face area (FFA) are brain regions thought to be specialized for face perception. However, their intrinsic functional organization and status as cortical areas with well-defined boundaries remains unclear. Here we test these regions for “faciotopy”, a particular hypothesis about their intrinsic functional organisation. A faciotopic area would contain a face-feature map on the cortical surface, where cortical patches represent face features and neighbouring patches represent features that are physically neighbouring in a face. The faciotopy hypothesis is motivated by the idea that face regions might develop from a retinotopic protomap and acquire their selectivity for face features through natural visual experience. Faces have a prototypical configuration of features, are usually perceived in a canonical upright orientation, and are frequently fixated in particular locations. To test the faciotopy hypothesis, we presented images of isolated face features at fixation to subjects during functional magnetic resonance imaging. The responses in V1 were best explained by low-level image properties of the stimuli. OFA, and to a lesser degree FFA, showed evidence for faciotopic organization. When a single patch of cortex was estimated for each face feature, the cortical distances between the feature patches reflected the physical distance between the features in a face. Faciotopy would be the first example, to our knowledge, of a cortical map reflecting the topology, not of a part of the organism itself (its retina in retinotopy, its body in somatotopy), but of an external object of particular perceptual significance. PMID:26235800

  16. 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

  17. Color and spatial error in block design in stone-age Auca Indians: ecological underuse of occipital-parietal system in men and of frontal lobes in women.

    PubMed

    Pontius, A A

    1989-05-01

    The entire healthy adult population of 19 nonmissionized nomadic Auca Indians of the Ecuadorian Amazon basin were given tests involving the four-colored Kohs Block Design, spatial-relational, lexical, and body and face shapes. The test results reveal a specific grouping of deficiencies in color naming (with preservation of color concept), block design especially related to representation, and construction of certain intrapattern spatial relations and graphic representational skills. This ecologically determined grouping of deficiencies suggests a homology to certain neuropsychological syndromes (E. Stengel, 1948, Journal of Mental Science, 94, 46-58; J. de Ajuriaguerra & H. Hécaen, 1960, Le cortex cérébrale; N. Geschwind & M. Fusillo, 1966, Archives of Neurology, 15, 137-146). Further, specifically deficient components of constructional praxis (A. R. Luria & L. S. Tsvetkova, 1964, Neuropsychologia, 2, 95-107) are proposed to reflect gender-related limitations of daily tasks, suggesting occipital-parietal underuse in Auca men and frontal system underuse in Auca women. PMID:2713145

  18. Is the Medial Prefrontal Cortex Necessary for Theory of Mind?

    PubMed Central

    Otti, Alexander; Wohlschlaeger, Afra M.; Noll-Hussong, Michael

    2015-01-01

    Background Successful social interaction relies on the ability to attribute mental states to other people. Previous functional neuroimaging studies have shown that this process, described as Theory of Mind (ToM) or mentalization, is reliably associated with activation of the medial prefrontal cortex (mPFC). However, this study presents a novel and surprising finding that provides new insight into the role of the mPFC in mentalization tasks. Methodology/Principal Findings Twenty healthy individuals were recruited from a wide range of ages and social backgrounds. Participants underwent functional magnetic resonance imaging (fMRI) while viewing a well-established ToM visual paradigm involving moving triangles. Functional MRI data were analyzed using a classical general linear model. No activation was detected in the medial prefrontal cortex (mPFC) during movement patterns that typically elicit ToM. However, increased activity was observed in the right middle occipital gyrus, right temporoparietal junction (TPJ), left middle occipital gyrus and right inferior frontal gyrus. No correlation was found between participants’ age and BOLD response. Conclusions/Significance In contrast with previous neuroimaging research, our findings support the notion that mPFC function is not critical for reasoning about the mental states of others; furthermore, our data indicate that the right TPJ and right inferior frontal gyrus are able to perform mentalization without any contributions from the mPFC. PMID:26301900

  19. 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

  20. The Visual Word Form Area remains in the dominant hemisphere for language in late-onset left occipital lobe epilepsies: A postsurgery analysis of two cases.

    PubMed

    Lopes, Ricardo; Nunes, Rita Gouveia; Simões, Mário Rodrigues; Secca, Mário Forjaz; Leal, Alberto

    2015-05-01

    Automatic recognition of words from letter strings is a critical processing step in reading that is lateralized to the left-hemisphere middle fusiform gyrus in the so-called Visual Word Form Area (VWFA). Surgical lesions in this location can lead to irreversible alexia. Very early left hemispheric lesions can lead to transfer of the VWFA to the nondominant hemisphere, but it is currently unknown if this capability is preserved in epilepsies developing after reading acquisition. In this study, we aimed to determine the lateralization of the VWFA in late-onset left inferior occipital lobe epilepsies and also the effect of surgical disconnection from the adjacent secondary visual areas. Two patients with focal epilepsies with onset near the VWFA underwent to surgery for epilepsy, with sparing of this area. Neuropsychology evaluations were performed before and after surgery, as well as quantitative evaluation of the speed of word reading. Comparison of the surgical localization of the lesion, with the BOLD activation associated with the contrast of words-strings, was performed, as well as a study of the associated main white fiber pathways using diffusion-weighted imaging. Neither of the patients developed alexia after surgery (similar word reading speed before and after surgery) despite the fact that the inferior occipital surgical lesions reached the neighborhood (less than 1cm) of the VWFA. Surgeries partly disconnected the VWFA from left secondary visual areas, suggesting that pathways connecting to the posterior visual ventral stream were severely affected but did not induce alexia. The anterior and superior limits of the resection suggest that the critical connection between the VWFA and the Wernicke's Angular Gyrus cortex was not affected, which is supported by the detection of this tract with probabilistic tractography. Left occipital lobe epilepsies developing after reading acquisition did not produce atypical localizations of the VWFA, even with foci in the close neighborhood. Surgery for occipital lobe epilepsy should take this into consideration, as well as the fact that disconnection from the left secondary visual areas may not produce alexia. PMID:25940105

  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. Sounds Activate Visual Cortex and Improve Visual Discrimination

    PubMed Central

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

    2014-01-01

    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

  3. Airway management for occipital encephalocele in neonatal patients: A review of 17 cases

    PubMed Central

    Y?ld?r?m, Zeynep Baysel; Avci, Emel; Torun, Fuat; Cengiz, Mustafa; Çigdem, Ali; Karaba?, Hamza; Karaman, Haktan

    2011-01-01

    Introduction: Encephalocele, midline defect of cranial bone fusion, occurs most frequently in the occipital region. Airway management in pediatric patients with craniofacial disorders poses many challenges to the anesthesiologist. The purpose of this study is to describe the airway problems encountered for such cases, and describe how these problems were managed. Materials and Methods: We reviewed the charts of occipital encephalocele newborn that were treated by surgical correction in Harran University Hospital during 2006–2008. The collected data were categorized into preoperative, intraoperative, and postoperative data. Results: The mean age of the patients was 5.17 days. Of these 17 patients, eight patients (47.1%) had hydrocephaly, one patient (5.8%) with Dandy Walker syndrome. Micrognathia, macroglossia, restriction in neck movements were recorded as the reasons in six cases each. No major anesthetic complication was found. Conclusions: We reported perioperative management in 17 occipital encephalocele infant. Comprehensive care during peroperative period is essential for successful outcome. PMID:21897680

  4. Thrombosed traumatic aneurysm of the occipital artery: a case report and review of the literature

    PubMed Central

    2012-01-01

    Introduction Occipital artery aneurysms are very rare vascular lesions. Most cases reported in the literature have been post-traumatic pseudoaneurysms of the occipital artery. Case presentation We report the case of a 14-year-old Caucasian boy presented with a painless non-pulsatile scalp mass that developed rapidly after minor blunt head trauma. The scalp mass was excised six months after the trauma. A pathologic diagnosis of a thrombosed true aneurysm was made. Our patient has had no recurrence of the mass at 15?months follow-up. Conclusions We present a case of a true aneurysm of the occipital artery following minor head trauma. We review the literature for similar cases and discuss the difficulty of establishing a diagnosis prior to surgical intervention. PMID:22804804

  5. Occipital meningoencephalocele with Cleft Lip, Cleft Palate and Limb Abnormalities- A Case Report

    PubMed Central

    T, Sadeesh; Swer, Mary Hydrina; Rao, Sudha

    2014-01-01

    A 21-week-old still born female fetus with occipital encepholocele, cleft lip and cleft palate was received from the Department of Obstetrics and Gynecology, Mahatma Gandhi Medical College and Research Institute, Pondicherry and was studied in detail. It was born to Primigravida, of a second degree consanguineous marriage, with unremarkable family history. The biometric measurements were noted which corresponded to the age of the fetus. Further the fetus was embalmed and dissected. On examination an encephalocele of 2.7×1.5 cm was seen in the occipital region with a midline defect in the occipital bone and herniated brain tissue. Other anomalies observed were right unilateral cleft lip, right cleft palate, and bilateral syndactyly of the lower limbs and associated Congenital Talipus Equino Varus of the right foot. Other internal organs were developed appropriate for the age of the fetus. PMID:25653933

  6. Hemodynamic Response to Featural Changes in the Occipital and Inferior Temporal Cortex in Infants: A Preliminary Methodological Exploration

    ERIC Educational Resources Information Center

    Wilcox, Teresa; Bortfeld, Heather; Woods, Rebecca; Wruck, Eric; Boas, David A.

    2008-01-01

    Over the past 30 years researchers have learned a great deal about the development of object processing in infancy. In contrast, little is understood about the neural mechanisms that underlie this capacity, in large part because there are few techniques available to measure brain functioning in human infants. The present research examined the…

  7. Parieto-occipital encephalomalacia in neonatal hyperammonemia with ornithine transcarbamylase deficiency: A case report.

    PubMed

    Okanishi, Tohru; Ito, Tetsuya; Nakajima, Yoko; Ito, Koichi; Kakita, Hiroki; Yamada, Yasumasa; Kobayashi, Satoru; Ando, Naoki; Togari, Hajime

    2010-08-01

    Urea cycle disorders are congenital metabolic disorders that often cause episodic hyperammonemia. Neuroimaging in episodic hyperammonemia demonstrates several patterns of brain injuries, including focal lesions in the lentiform nucleus, insula, cingulate gyrus, and perirolandic fissure, as well as diffuse cerebral edema. In cases with neonatal onset of hyperammonemia, similar lesions have also been reported. We herein report a boy with severe neonatal hyperammonemia caused by ornithine transcarbamylase deficiency. He presented with parieto-occipital encephalomalacia, which resembles severe neonatal hypoglycemia on magnetic resonance imaging. This radiological finding may indicate parieto-occipital vulnerability not only to hypoglycemia but also to hyperammonemia. PMID:19640662

  8. Benign occipital unicameral bone cyst causing lower cranial nerve palsies complicated by iophendylate arachnoiditis

    PubMed Central

    Bradley, W. G.; Kalbag, R. M.; Ramani, P. S.; Tomlinson, B. E.

    1974-01-01

    A 20 year old girl presented with a history of neck and occipital pain for six weeks, which was found to be due to a unicameral bone cyst of the left occipital condylar region. The differential diagnosis of bone cysts in the skull is discussed. Six months after the operation, the patient again presented with backache due to adhesive arachnoiditis. The latter was believed to have arisen as a result of a combination of spinal infective meningitis and intrathecal ethyl iodophenyl undecylate (iophendylate, Myodil, Pantopaque). The nature of meningeal reactions to iophendylate and the part played by intrathecal corticosteroids in relieving the arachnoiditis in the present case are discussed. Images

  9. Supporting Information to SherLoc2: a high-accuracy hybrid method for predicting subcellular

    E-print Network

    localization of proteins August 31, 2009 1 Cross-validation test SherLoc2 was tested via 5-fold cross.91 0.91 0.92 pm 1238 0.94 0.95 0.95 0.95 0.95 0.95 pe 157 0.98 0.87 0.96 0.88 0.97 0.87 er 198 0.92 0) (abbreviations from the paper are used) the number of proteins (No.) is shown. For each organism and subcellular

  10. Aptamer-NASBA LOC as a prospective tool for systemic therapy of cancer: quantitative detection on signaling molecular profiling.

    PubMed

    Zhao, Xinyan; Dong, Tao; Yang, Zhaochu; Karlsen, Haakon

    2012-01-01

    As the present technology of cancer treatment cannot cure the diseases, a prospective therapy, named 'systemic therapy', brings forth a new trend in cancer treatment. The aptamer-NASBA-based lab-on-a-chip (LOC) for systemic therapy was designed, fabricated and tested as an ultra-sensitive tool to monitor signaling molecular profiling in serum samples. The chip is divided into four parallel functional areas, corresponding to four groups of signaling molecules (i.e. hormones, neurotransmitters, cytokines and tumor biomarkers). The results can help doctors fully understand the body of patients. The chip is modeled on a 384-well microplate, which is completely compatible with common microplate readers in a biological laboratory. It can distinguish 24 signaling molecules in the same blood sample quantitatively and simultaneously. The chip was made of PDMS and silicon with a deposited gold layer, which was coated by aptamers before bonding; then, the LOC was operated by external valves and a vacuum pump. Its performance was demonstrated by detecting the presence of a synthetic peptide, GnRH (gonadotropin-releasing hormone) in artificial samples. The results indicated that the LOC has the potential to quantify traces of biomarkers even at subfemtomolar levels. Compared with our previous immuno-NASBA LOC, the aptamer-NASBA LOC showed an increased sensitivity and better repeatability. PMID:23365958

  11. Understanding the nature of visual short-term memory representation in human parietal cortex.

    PubMed

    Bettencourt, Katherine; Xu, Yaoda

    2015-09-01

    Recent work has shown that the human parietal cortex, in particular superior intraparietal sulcus (IPS), plays a central role in visual short-term memory (VSTM) storage. However, much remains unknown about the nature of these memory representations including whether they are similar or distinct from perceptual representations. Using fMRI multivariate pattern analysis (MVPA), it has been shown that VSTM representations in occipital cortex are highly similar to perceptual representations. Here, we tested whether the same would be true for VSTM representations in superior IPS. On the one hand, VSTM representations in superior IPS could simply be an extension of the sensory representations formed during perception. This would predict a high degree of similarity between VSTM and perceptual representations in this region. However, we have previously shown that VSTM representations in superior IPS, unlike those in occipital cortex, are robust to visual distraction. This suggests that the nature of VSTM representation in the two regions may differ, and that representations in superior IPS may be consolidated and thus, distinct from perceptual representations. In the present study, we had participants complete both a VSTM and perceptual task using face and gazebo stimuli. We then decoded between the two stimuli types both within a task and across the two tasks. To minimize any attention or memory effects in the perceptual task, participants performed a one back letter task at fixation. Pilot results showed decoding of both memory and perceptual information in superior IPS, and, importantly, successful cross decoding between the two tasks. This suggests that, just like in occipital cortex, VSTM information in superior IPS is represented in a similar manner to perceptual information. Meeting abstract presented at VSS 2015. PMID:26325980

  12. Abnormal visual field maps in human cortex: a mini-review and a case report.

    PubMed

    Haak, Koen V; Langers, Dave R M; Renken, Remco; van Dijk, Pim; Borgstein, Johannes; Cornelissen, Frans W

    2014-07-01

    Human visual cortex contains maps of the visual field. Much research has been dedicated to answering whether and when these visual field maps change if critical components of the visual circuitry are damaged. Here, we first provide a focused mini-review of the functional magnetic resonance imaging (fMRI) studies that have evaluated the human cortical visual field maps in the face of retinal lesions, brain injury, and atypical retinocortical projections. We find that there is a fair body of research that has found abnormal fMRI activity, but also that this abnormal activity does not necessarily stem from cortical remapping. The abnormal fMRI activity can often be explained in terms of task effects and/or the uncovering of normally hidden system dynamics. We then present the case of a 16-year-old patient who lost the entire left cerebral hemisphere at age three for treatment of chronic focal encephalitis (Rasmussen syndrome) and intractable epilepsy. Using an fMRI retinotopic mapping procedure and population receptive field (pRF) modeling, we found that (1) despite the long period since the hemispherectomy, the retinotopic organization of early visual cortex remained unaffected by the removal of an entire cerebral hemisphere, and (2) the intact lateral occipital cortex contained an exceptionally large representation of the center of the visual field. The same method also indicates that the neuronal receptive fields in these lateral occipital brain regions are extraordinarily small. These features are clearly abnormal, but again they do not necessarily stem from cortical remapping. For example, the abnormal features can also be explained by the notion that the hemispherectomy took place during a critical period in the development of the lateral occipital cortex and therefore arrested its normal development. Thus, caution should be exercised when interpreting abnormal fMRI activity as a marker of cortical remapping; there are often other explanations. PMID:23347557

  13. Cortex Morphology in First-Episode Psychosis Patients With Neurological Soft Signs

    PubMed Central

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

    2013-01-01

    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

  14. 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

  15. 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

  16. Irreversible Loss of Vision in a Child due to Occipital Infarction after Gastroenteritis

    PubMed Central

    Mansour, Ahmad M.; Hasbini, Dana; Younis, Muhammad H.; Bhatti, M. Tariq

    2015-01-01

    A 2½-year-old girl developed a bilateral occipital infarct following severe gastroenteritis with bilateral vision of light perception. Evaluations for sickle cell anemia, hemolytic anemia and coagulopathies were negative. Cortical blindness is an uncommon but dramatic complication of gastroenteritis, hence the need of prompt hydration and other supportive measures to avoid irreversible visual loss or mental sequela. PMID:25960732

  17. 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

  18. A giant occipital encephalocele with spontaneous hemorrhage into the sac: A rare case report

    PubMed Central

    Nath, H. D.; Mahapatra, A. K.; Borkar, S. A.

    2014-01-01

    In giant encephalocele, head size is smaller than the encelphalocele. Occipital encephalocele is the commonest of all encephalocele. In our case, there was rare association with giant encephalocele with old hemorrhage in the sac. This was a unique presentation. In world literature, there was rare association with giant encephalocele with hemorrhage. PMID:25685207

  19. A giant occipital encephalocele with spontaneous hemorrhage into the sac: A rare case report.

    PubMed

    Nath, H D; Mahapatra, A K; Borkar, S A

    2014-01-01

    In giant encephalocele, head size is smaller than the encelphalocele. Occipital encephalocele is the commonest of all encephalocele. In our case, there was rare association with giant encephalocele with old hemorrhage in the sac. This was a unique presentation. In world literature, there was rare association with giant encephalocele with hemorrhage. PMID:25685207

  20. Elementary visual hallucinations, blindness, and headache in idiopathic occipital epilepsy: differentiation from migraine

    PubMed Central

    Panayiotopoulos, C

    1999-01-01

    This is a qualitative and chronological analysis of ictal and postictal symptoms, frequency of seizures, family history, response to treatment, and prognosis in nine patients with idiopathic occipital epilepsy and visual seizures. Ictal elementary visual hallucinations are stereotyped for each patient, usually lasting for seconds. They consist of mainly multiple, bright coloured, small circular spots, circles, or balls. Mostly, they appear in a temporal hemifield often moving contralaterally or in the centre where they may be flashing. They may multiply and increase in size in the course of the seizure and may progress to other non-visual occipital seizure symptoms and more rarely to extra-occipital manifestations and convulsions. Blindness occurs usually from the beginning and postictal headache, often indistinguishable from migraine, is common. It is concluded that elementary visual hallucinations in occipital seizures are entirely different from visual aura of migraine when individual elements of colour, shape, size, location, movement, speed of development, duration, and progress are synthesised together. Postictal headache does not show preference for those with a family history of migraine. Most of the patients are misdiagnosed as having migraine with aura, basilar migraine, acephalgic migraine, or migralepsy simply because physicians are not properly informed of differential diagnostic criteria. As a result, treatment may be delayed for years. Response to carbamazepine is excellent and seizures may remit.?? PMID:10201433

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

    E-print Network

    Wisconsin at Madison, University of

    Experienced Mindfulness Meditators Exhibit Higher Parietal-Occipital EEG Gamma Activity during NREM meditation practice has gained increasing attention as a non-pharmacological intervention to provide health conditions. However, the effects of meditation training on brain activity still need to be fully

  2. Adult-onset photosensitivity: clinical significance and epilepsy syndromes including idiopathic (possibly genetic) photosensitive occipital epilepsy.

    PubMed

    Koutroumanidis, Michalis; Tsirka, Vasiliki; Panayiotopoulos, Chrysostomos

    2015-09-01

    To evaluate the clinical associations of adult-onset photosensitivity, we studied the clinical and EEG data of patients who were referred due to a possible first seizure and who had a photoparoxysmal response on their EEG. Patients with clinical evidence of photosensitivity before the age of 20 were excluded. Of a total of 30 patients, four had acute symptomatic seizures, two had vasovagal syncope, and 24 were diagnosed with epilepsy. Nine of the 24 patients had idiopathic (genetic) generalized epilepsies and predominantly generalized photoparoxysmal response, but also rare photically-induced seizures, while 15 had exclusively, or almost exclusively, reflex photically-induced occipital seizures with frequent secondary generalization and posterior photoparoxysmal response. Other important differences included a significantly older age at seizure onset and paucity of spontaneous interictal epileptic discharges in patients with photically-induced occipital seizures; only a quarter of these had occasional occipital spikes, in contrast to the idiopathic (genetic) generalized epilepsy patients with typically generalized epileptic discharges. On the other hand, both groups shared a positive family history of epilepsy, common seizure threshold modulators (such as tiredness and sleep deprivation), normal neurological examination and MRI, a generally benign course, and good response to valproic acid. We demonstrated that photosensitivity can first occur in adult life and manifest, either as idiopathic (possibly genetic) photosensitive occipital epilepsy with secondary generalization or as an EEG, and less often, a clinical/EEG feature of idiopathic (genetic) generalized epilepsies. Identification of idiopathic photosensitive occipital epilepsy fills a diagnostic gap in adult first-seizure epileptology and is clinically important because of its good response to antiepileptic drug treatment and fair prognosis. PMID:26293003

  3. Representations in auditory cortex.

    PubMed

    Hromádka, Tomás; Zador, Anthony M

    2009-08-01

    How does auditory cortex represent auditory stimuli, and how do these representations contribute to behavior? Recent experimental evidence suggests that activity in auditory cortex consists of sparse and highly synchronized volleys of activity, observed both in anesthetized and awake animals. Many neurons are capable of remarkably precise activity with very low jitter or spike count variability. Most importantly, animals are capable of exploiting such precise neuronal activity in making sensory decisions. Whether the ability of auditory cortex to exploit fine temporal differences in cortical activity is unique to auditory modality, or represents a general strategy used by cortical circuits remains an open question. PMID:19674890

  4. 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

  5. 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

  6. Freiburg RNA Tools: a web server integrating IntaRNA, ExpaRNA and LocARNA

    E-print Network

    Smith, Cameron

    The Freiburg RNA tools web server integrates three tools for the advanced analysis of RNA in a common web-based user interface. The tools IntaRNA, ExpaRNA and LocARNA support the prediction of RNA–RNA interaction, exact ...

  7. Verslag Vergadering 67 LOC/NOC (Landelijke en NOVA Onderwijs Commissie) PLAATS: Utrecht, BBL 702 (koffiekamer SIU)

    E-print Network

    Peletier, Reynier

    Verslag Vergadering 67 LOC/NOC (Landelijke en NOVA Onderwijs Commissie) PLAATS: Utrecht, BBL 702 evaluatie rapport over de laatste NOVA herfstschool nog is rondgestuurd, dit zal ter sprake komen bij LOCNOC van de NOVA site gebruik kan maken om een eigen webpagina op te zetten. De LOCNOC website komt

  8. 56 lNropurlanoNeNnTEcm{oLocYRpponr I Fixed-width Aerial Transects for Determining Dugong Population

    E-print Network

    Marsh, Helene

    56 lNropurlanoNeNnTEcm{oLocYRpponr I Fixed-width Aerial Transects for Determining Dugong Population-levelchronicdeclinein dugongabundanceevenata largespatialscalewouldtakeaboutonedecade. Keywords: Aerialsurveytechniques,biascorrections,dugong,Dugongdugon' The range of the dugong (Dugong dugon) extends throughout the tropical and subtropicalcoastaland island

  9. Current and emerging technology in G-LOC detection: noninvasive monitoring of cerebral microcirculation using near infrared.

    PubMed

    Glaister, D H

    1988-01-01

    G-induced loss of consciousness (G-LOC) has emerged as an important operational problem of high-performance aircraft. Since it appears that G-LOC will continue to be a problem, a requirement exists to detect its occurrence in pilots so that the aircraft may be placed on autopilot. One excellent method of detecting G-LOC physiologically, one would assume, would be based on the oxidative status of the brain. This determination can be made noninvasively with an Oxidative Metabolism Near-Infrared monitor using 4 wave lengths (OMNI-4). The OMNI-4 is capable of measuring the relative quantities in the brain of hemoglobin (Hb), oxygenated hemoglobin (HbO2), blood volume (BV), and oxidative status of cytochrome c oxidase. This instrument was tested on subjects in the USAFSAM human-use centrifuge at +3, 4, and 5 Gz with onset rates of 1 G.s-1. Results showed changes within the brain, as expected, during increased G with reductions in Hb, BV, and HbO2. Cytochrome c oxidase measurements were inconclusive. Immediately following G exposure, Hb, BV, and HbO2 "overshoots" occurred suggesting vasodilation of the cerebral microcirculation. The use of OMNI-4 in the laboratory and its possible role as a detector of G-LOC in pilots are discussed including suggestions for future developments. PMID:3355461

  10. LAURA -LocAlization and Ubiquitous monitoRing of pAtients for health care support

    E-print Network

    Tagliasacchi, Marco

    LAURA - LocAlization and Ubiquitous monitoRing of pAtients for health care support Alessandro based on the IEEE 801.15.4 (Zigbee) standard. We focus on the indoor personal localization module, which and tracking system using commercial hardware, and we test the LAURA system in real environment, both

  11. TECHNICAL NOTE www.rsc.org/loc | Lab on a Chip Neutravidin micropatterning by deep UV irradiation

    E-print Network

    Hancock, William O.

    TECHNICAL NOTE www.rsc.org/loc | Lab on a Chip Neutravidin micropatterning by deep UV irradiation February 2008, Accepted 16th June 2008 First published as an Advance Article on the web 13th August 2008 by exposure to deep UV irradiation. Neutravidin is physically absorbed onto the glass or quartz substrate

  12. TMS to object cortex affects both object and scene remote networks while TMS to scene cortex only affects scene networks.

    PubMed

    Rafique, Sara A; Solomon-Harris, Lily M; Steeves, Jennifer K E

    2015-12-01

    Viewing the world involves many computations across a great number of regions of the brain, all the while appearing seamless and effortless. We sought to determine the connectivity of object and scene processing regions of cortex through the influence of transient focal neural noise in discrete nodes within these networks. We consecutively paired repetitive transcranial magnetic stimulation (rTMS) with functional magnetic resonance-adaptation (fMR-A) to measure the effect of rTMS on functional response properties at the stimulation site and in remote regions. In separate sessions, rTMS was applied to the object preferential lateral occipital region (LO) and scene preferential transverse occipital sulcus (TOS). Pre- and post-stimulation responses were compared using fMR-A. In addition to modulating BOLD signal at the stimulation site, TMS affected remote regions revealing inter and intrahemispheric connections between LO, TOS, and the posterior parahippocampal place area (PPA). Moreover, we show remote effects from object preferential LO to outside the ventral perception network, in parietal and frontal areas, indicating an interaction of dorsal and ventral streams and possibly a shared common framework of perception and action. PMID:26511624

  13. 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

  14. Density and Frequency Caudo-Rostral Gradients of Sleep Spindles Recorded in the Human Cortex

    PubMed Central

    Peter-Derex, Laure; Comte, Jean-Christophe; Mauguière, François; Salin, Paul A.

    2012-01-01

    Study Objective: This study aims at providing a quantitative description of intrinsic spindle frequency and density (number of spindles/min) in cortical areas using deep intracerebral recordings in humans. Patients or Participants: Thirteen patients suffering from pharmaco-resistant focal epilepsy and investigated through deep intracortical EEG in frontal, parietal, temporal, occipital, insular, and limbic cortices including the hippocampus were included. Methods: Spindle waves were detected from the ongoing EEG during slow wave sleep (SWS) by performing a time-frequency analysis on filtered signals (band-pass filter: 10-16 Hz). Then, spindle intrinsic frequency was determined using a fast Fourier transform, and spindle density (number of spindles per minute) was computed. Results: Firstly, we showed that sleep spindles were recorded in all explored cortical areas, except temporal neocortex. In particular, we observed the presence of spindles during SWS in areas such as the insular cortex, medial parietal cortex, occipital cortex, and cingulate gyrus. Secondly, we demonstrated that both spindle frequency and density smoothly change along the caudo-rostral axis, from fast frequent posterior spindles to slower and less frequent anterior spindles. Thirdly, we identified the presence of spindle frequency oscillations in the hippocampus and the entorhinal cortex. Conclusions: Spindling activity is widespread among cortical areas, which argues for the fundamental role of spindles in cortical functions. Mechanisms of caudo-rostral gradient modulation in spindle frequency and density may result from a complex interplay of intrinsic properties and extrinsic modulation of thalamocortical and corticothalamic neurons. Citation: Peter-Derex L; Comte JC; Mauguière F; Salin PA. Density and frequency caudo-rostral gradients of sleep spindles recorded in the human cortex. SLEEP 2012;35(1):69-79. PMID:22215920

  15. 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. PMID:26136602

  16. Neurofibromatosis Type 1: Transcatheter Arterial Embolization for Ruptured Occipital Arterial Aneurysms

    SciTech Connect

    Kanematsu, Masayuki; Kato, Hiroki; Kondo, Hiroshi; Goshima, Satoshi; Tsuge, Yusuke; Kojima, Toshiaki; Watanabe, Haruo

    2011-02-15

    Two cases of ruptured aneurysms in the posterior cervical regions associated with type-1 neurofibromatosis treated by transcatheter embolization are reported. Patients presented with acute onset of swelling and pain in the affected areas. Emergently performed contrast-enhanced CT demonstrated aneurysms and large hematomas widespread in the posterior cervical regions. Angiography revealed aneurysms and extravasations of the occipital artery. Patients were successfully treated by percutaneous transcatheter arterial microcoil embolization. Transcatheter arterial embolization therapy was found to be an effective method for treating aneurysmal rupture in the posterior cervical regions occurring in association with type-1 neurofibromatosis. A literature review revealed that rupture of an occipital arterial aneurysm, in the setting of neurofibromatosis type 1, has not been reported previously.

  17. Hypoglycemia-occipital syndrome: a specific neurologic syndrome following neonatal hypoglycemia?

    PubMed

    Karimzadeh, Parvaneh; Tabarestani, Sepideh; Ghofrani, Mohammad

    2011-02-01

    This study attempted to elaborate the existence of a specific neurologic pattern observed in children who experienced neonatal hypoglycemia. Twenty-seven patients with seizure and history of neonatal hypoglycemia were compared with 28 children suffering from idiopathic occipital epilepsy. In both groups the most common type of seizure activities included eye movements and impaired consciousness responding well to treatment; however, ictal vomiting was more common in controls. Subjects were in epileptic and nonepileptic groups. Ninety percent of cases showed abnormal signal of the posterior head region on magnetic resonance imaging (MRI). A large number showed posterior abnormalities on electroencephalography (EEG). Visual loss with abnormal visual evoked potential was the most frequent visual finding. Fifty-five percent showed mild psychomotor retardation. This study demonstrates that neonatal hypoglycemia can induce a syndrome with a specific clinical spectrum consisting of epilepsy, visual disturbances, and psychomotor retardation. Hypoglycemia-occipital syndrome is an entity without statistically significant semiologic differences from the idiopathic type. PMID:20639407

  18. 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

  19. 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

  20. Occipital calcified pseudoneoplasms of the neuraxis (CAPNON): understanding a rare pathology.

    PubMed

    Lyapichev, Kirill; Bregy, Amade; Shah, Ashish H; Shah, Kinjal; Desai, Mehul B; Petito, Carol; Komotar, Ricardo J

    2014-01-01

    Calcifying pseudoneoplasms of the neuraxis (CAPNON) are rare and typically benign lesions that can occur anywhere within the central nervous system. Aetiology of this lesion is unclear and surgical removal is usually curative. We present a 24-year-old male patient with a history of occipital migraines who was admitted after sudden onset seizure and loss of vision. CT and MRI demonstrated a small calcifying lesion in the right temporo-occipital lobe. The patient underwent gross total resection of the tumour mass and pathological analysis revealed a CAPNON. The preoperative diagnosis of CAPNON remains difficult due to unspecific radiological findings, yet a clear understanding of characteristic pathological findings and prognosis of CAPNON remains paramount. PMID:25480139

  1. Outcomes of Greater Occipital Nerve Injections in Pediatric Patients with Chronic Primary Headache Disorders

    PubMed Central

    Gelfand, Amy A.; Reider, Amanda C.; Goadsby, Peter J.

    2014-01-01

    Background Chronic migraine is common in pediatrics and generally disabling. In adults, infiltration of the area around the greater occipital nerve can provide short to medium term benefit in some patients. This study reports the efficacy of greater occipital nerve infiltrations in pediatric patients with chronic primary headache disorders. Methods Retrospective chart review of patients <18 years with a chronic primary headache disorder undergoing a first-time injection. Infiltrations were unilateral and consisted of a mixture of methylprednisolone acetate, adjusted for weight, and lidocaine 2%. Results Forty-six patients were treated. Thirty-five (76%) had chronic migraine, nine (20%) New Daily Persistent Headache (NDPH), and two (4%) a chronic trigeminal autonomic cephalalgia. Medication overuse was present in 26%. Ages ranged from 7–17 years. Follow-up data were available for 40 (87%). Overall, 53% (21/40) benefitted, 52% (11/21) significantly. Benefit onset ranged from 0–14 days, mean 4.7(SD 4.3), with mean benefit duration of 5.4(SD 4.9) weeks. In chronic migraine, 62% (18/29) benefitted, 56% (10/18) significantly. In NDPH, 33% (3/9) benefitted; 33% (n=1) significantly. Neither child with a chronic trigeminal autonomic cephalalgia benefitted. In logistic regression modeling, medication overuse, age, sex, and sensory change in the distribution of the infiltrated nerve did not predict outcome. There were no serious side effects. Conclusions Greater occipital nerve injections benefitted 53% of pediatric patients with chronic primary headache disorders. Efficacy appeared higher in chronic migraine than NDPH. Given the benign side effect profile, a greater occipital nerve infiltration prior to more aggressive approaches seems appropriate. PMID:24268688

  2. Biofidelic neck influences head kinematics of parietal and occipital impacts following short falls in infants.

    PubMed

    Sullivan, Sarah; Coats, Brittany; Margulies, Susan S

    2015-09-01

    Falls are a major cause of traumatic head injury in children. Understanding head kinematics during low height falls is essential for evaluating injury risk and designing mitigating strategies. Typically, these measurements are made with commercial anthropomorphic infant surrogates, but these surrogates are designed based on adult biomechanical data. In this study, we improve upon the state-of-the-art anthropomorphic testing devices by incorporating new infant cadaver neck bending and tensile data. We then measure head kinematics following head-first falls onto 4 impact surfaces from 3 fall heights with occipital and parietal head impact locations. The biofidelic skull compliance and neck properties of the improved infant surrogate significantly influenced the measured kinematic loads, decreasing the measured impact force and peak angular accelerations, lowering the expected injury risk. Occipital and parietal impacts exhibited distinct kinematic responses in primary head rotation direction and the magnitude of the rotational velocities and accelerations, with larger angular velocities as the head rebounded after occipital impacts. Further evaluations of injury risk due to short falls should take into account the impact surface and head impact location, in addition to the fall height. PMID:26072183

  3. Dopamine D sub 2 receptors in the cerebral cortex: Distribution and pharmacological characterization with ( sup 3 H)raclopride

    SciTech Connect

    Lidow, M.S.; Goldman-Rakic, P.S.; Rakic, P.; Innis, R.B. )

    1989-08-01

    An apparent involvement of dopamine in the regulation of cognitive functions and the recognition of a widespread dopaminergic innervation of the cortex have focused attention on the identity of cortical dopamine receptors. However, only the presence and distribution of dopamine D{sub 1} receptors in the cortex have been well documented. Comparable information on cortical D{sub 2} sites is lacking. The authors report here the results of binding studied in the cortex and neostriatum of rat and monkey using the D{sub 2} selective antagonist ({sup 3}H)raclopride. In both structures ({sup 3}H)raclopride bound in a sodium-dependent and saturable manner to a single population of sites with pharmacological profiles of dopamine D{sub 2} receptors. D{sub 2} sites were present in all regions of the cortex, although their density was much lower than in the neostriatum. The density of these sites in both monkey and, to a lesser extent, rat cortex displayed a rostral-caudal gradient with highest concentrations in the prefrontal and lowest concentrations in the occipital cortex, corresponding to dopamine levels in these areas. Thus, the present study established the presence and widespread distribution of dopamine D{sub 2} receptors in the cortex.

  4. Effects of Visual Cortex Activation on the Nociceptive Blink Reflex in Healthy Subjects

    PubMed Central

    Sava, Simona L.; de Pasqua, Victor; Magis, Delphine; Schoenen, Jean

    2014-01-01

    Bright light can cause excessive visual discomfort, referred to as photophobia. The precise mechanisms linking luminance to the trigeminal nociceptive system supposed to mediate this discomfort are not known. To address this issue in healthy human subjects we modulated differentially visual cortex activity by repetitive transcranial magnetic stimulation (rTMS) or flash light stimulation, and studied the effect on supraorbital pain thresholds and the nociceptive-specific blink reflex (nBR). Low frequency rTMS that inhibits the underlying cortex, significantly decreased pain thresholds, increased the 1st nBR block ipsi- and contralaterally and potentiated habituation contralaterally. After high frequency or sham rTMS over the visual cortex, and rMS over the right greater occipital nerve we found no significant change. By contrast, excitatory flash light stimulation increased pain thresholds, decreased the 1st nBR block of ipsi- and contralaterally and increased habituation contralaterally. Our data demonstrate in healthy subjects a functional relation between the visual cortex and the trigeminal nociceptive system, as assessed by the nociceptive blink reflex. The results argue in favour of a top-down inhibitory pathway from the visual areas to trigemino-cervical nociceptors. We postulate that in normal conditions this visuo-trigeminal inhibitory pathway may avoid disturbance of vision by too frequent blinking and that hypoactivity of the visual cortex for pathological reasons may promote headache and photophobia. PMID:24936654

  5. How Visual Is the Visual Cortex? Comparing Connectional and Functional Fingerprints between Congenitally Blind and Sighted Individuals.

    PubMed

    Wang, Xiaoying; Peelen, Marius V; Han, Zaizhu; He, Chenxi; Caramazza, Alfonso; Bi, Yanchao

    2015-09-01

    Classical animal visual deprivation studies and human neuroimaging studies have shown that visual experience plays a critical role in shaping the functionality and connectivity of the visual cortex. Interestingly, recent studies have additionally reported circumscribed regions in the visual cortex in which functional selectivity was remarkably similar in individuals with and without visual experience. Here, by directly comparing resting-state and task-based fMRI data in congenitally blind and sighted human subjects, we obtained large-scale continuous maps of the degree to which connectional and functional "fingerprints" of ventral visual cortex depend on visual experience. We found a close agreement between connectional and functional maps, pointing to a strong interdependence of connectivity and function. Visual experience (or the absence thereof) had a pronounced effect on the resting-state connectivity and functional response profile of occipital cortex and the posterior lateral fusiform gyrus. By contrast, connectional and functional fingerprints in the anterior medial and posterior lateral parts of the ventral visual cortex were statistically indistinguishable between blind and sighted individuals. These results provide a large-scale mapping of the influence of visual experience on the development of both functional and connectivity properties of visual cortex, which serves as a basis for the formulation of new hypotheses regarding the functionality and plasticity of specific subregions. Significance statement: How is the functionality and connectivity of the visual cortex shaped by visual experience? By directly comparing resting-state and task-based fMRI data in congenitally blind and sighted subjects, we obtained large-scale continuous maps of the degree to which connectional and functional "fingerprints" of ventral visual cortex depend on visual experience. In addition to revealing regions that are strongly dependent on visual experience (early visual cortex and posterior fusiform gyrus), our results showed regions in which connectional and functional patterns are highly similar in blind and sighted individuals (anterior medial and posterior lateral ventral occipital temporal cortex). These results serve as a basis for the formulation of new hypotheses regarding the functionality and plasticity of specific subregions of the visual cortex. PMID:26354920

  6. 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

  7. EEG gamma-band phase synchronization between posterior and frontal cortex during mental rotation in humans.

    PubMed

    Bhattacharya, J; Petsche, H; Feldmann, U; Rescher, B

    2001-09-21

    The main purpose of the present paper was: (1) to study the phase synchronization pattern in the gamma-band while performing the classical Shepard-Metzler task of mental rotation; (2) to investigate the role of musical training; and (3) to study hemispheric differences in the degree of synchronization during mental rotation. Multivariate electroencephalograph signals from 20 male subjects (ten musicians and ten non-musicians) were recorded while performing the mental rotation task and also at resting condition. Phase synchronization was measured by a recent index, mean phase coherence. It was found that synchronization between frontal cortex and right parietal cortex was significantly increased during mental rotation with respect to rest, whereby musicians showed significantly higher degrees of synchronization than non-musicians. Left hemispheric dominance in the degree of phase synchronization, stronger in the posterior right parietal and occipital regions, was observed in musicians. Right hemispheric dominance was generally observed in non-musicians. PMID:11585560

  8. Freiburg RNA Tools: a web server integrating IntaRNA, ExpaRNA and LocARNA

    PubMed Central

    Smith, Cameron; Heyne, Steffen; Richter, Andreas S.; Will, Sebastian; Backofen, Rolf

    2010-01-01

    The Freiburg RNA tools web server integrates three tools for the advanced analysis of RNA in a common web-based user interface. The tools IntaRNA, ExpaRNA and LocARNA support the prediction of RNA–RNA interaction, exact RNA matching and alignment of RNA, respectively. The Freiburg RNA tools web server and the software packages of the stand-alone tools are freely accessible at http://rna.informatik.uni-freiburg.de. PMID:20444875

  9. MitoLoc: A method for the simultaneous quantification of mitochondrial network morphology and membrane potential in single cells

    PubMed Central

    Vowinckel, Jakob; Hartl, Johannes; Butler, Richard; Ralser, Markus

    2015-01-01

    Mitochondria assemble into flexible networks. Here we present a simple method for the simultaneous quantification of mitochondrial membrane potential and network morphology that is based on computational co-localisation analysis of differentially imported fluorescent marker proteins. Established in, but not restricted to, Saccharomyces cerevisiae, MitoLoc reproducibly measures changes in membrane potential induced by the uncoupling agent CCCP, by oxidative stress, in respiratory deficient cells, and in ?fzo1, ?ref2, and ?dnm1 mutants that possess fission and fusion defects. In combination with super-resolution images, MitoLoc uses 3D reconstruction to calculate six geometrical classifiers which differentiate network morphologies in ?fzo1, ?ref2, and ?dnm1 mutants, under oxidative stress and in cells lacking mtDNA, even when the network is fragmented to a similar extent. We find that mitochondrial fission and a decline in membrane potential do regularly, but not necessarily, co-occur. MitoLoc hence simplifies the measurement of mitochondrial membrane potential in parallel to detect morphological changes in mitochondrial networks. Marker plasmid open-source software as well as the mathematical procedures are made openly available. PMID:26184437

  10. Visual-Manual Exploration and Posterior Parietal Cortex in Humans

    PubMed Central

    Hinkley, Leighton B. N.; Krubitzer, Leah A.; Padberg, Jeff

    2009-01-01

    Areas of human posterior parietal cortex (PPC) specialized for processing sensorimotor information associated with visually locating an object, reaching to grasp, and manually exploring that object were examined using functional MRI. Cortical activation was observed in response to three tasks: 1) saccadic eye movements, 2) visually guided reaching to grasp, and 3) manual shape discrimination. During saccadic eye movements, cortical fields within the lateral and rostral superior parietal lobe (SPL) and the caudal SPL and parieto-occipital boundary were active. During visually guided reaching to grasp, regions of cortex within the postcentral sulcus (PoCS) and rostral intraparietal sulcus (IPS) were active, as well as the caudal SPL of the left hemisphere and the medial and caudal IPS of the right hemisphere. Cortical regions at the junction of the IPS and PoCS and an area in the medial SPL were active bilaterally during shape manipulation. Only a few regions were most active during a single motor behavior, whereas several areas were highly active during two or more tasks. Hemispheric asymmetries in activation patterns were observed during visually guided reaching to grasp. The gross areal organization of human PPC is likely similar to the pattern previously described in nonhuman primates, including multifunctional regions and asymmetric processing of some manual abilities. PMID:19812283

  11. Increased Visual Stimulation Systematically Decreases Activity in Lateral Intermediate Cortex

    PubMed Central

    Nasr, Shahin; Stemmann, Heiko; Vanduffel, Wim; Tootell, Roger B. H.

    2015-01-01

    Previous studies have attributed multiple diverse roles to the posterior superior temporal cortex (STC), both visually driven and cognitive, including part of the default mode network (DMN). Here, we demonstrate a unifying property across this multimodal region. Specifically, the lateral intermediate (LIM) portion of STC showed an unexpected feature: a progressively decreasing fMRI response to increases in visual stimulus size (or number). Such responses are reversed in sign, relative to well-known responses in classic occipital temporal visual cortex. In LIM, this “reversed” size function was present across multiple object categories and retinotopic eccentricities. Moreover, we found a significant interaction between the LIM size function and the distribution of subjects' attention. These findings suggest that LIM serves as a part of the DMN. Further analysis of functional connectivity, plus a meta-analysis of previous fMRI results, suggests that LIM is a heterogeneous area including different subdivisions. Surprisingly, analogous fMRI tests in macaque monkeys did not reveal a clear homolog of LIM. This interspecies discrepancy supports the idea that self-referential thinking and theory of mind are more prominent in humans, compared with monkeys. PMID:25480358

  12. 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

  13. Incidence of neuropathic pain after radiofrequency denervation of the third occipital nerve.

    PubMed

    Gazelka, Halena M; Knievel, Sarah; Mauck, William D; Moeschler, Susan M; Pingree, Matthew J; Rho, Richard H; Lamer, Tim J

    2014-01-01

    The purpose of this study was to identify the incidence of neuropathic pain occurring after radiofrequency neurotomy of the third occipital nerve (TON). This study was conducted at a teaching hospital from January 1, 2008, to March 31, 2010. With institutional review board approval, Current Procedural Terminology codes were used to identify patients who received radiofrequency ablation (RFA) of the nerves supplying the C2-3 facet joint and the TON. The C3 dorsal ramus provides innervation to the C2-3 facet joint and the suboccipital cutaneous region, and procedures that included ablation to this region were reviewed for complications. Postprocedural data were collected by reviewing follow-up appointment notes and telephone calls. Included were patients who had new neuropathic pain in the distribution of the TON after RFA. They described what they were feeling as burning, tingling, or numbness. All patients who presented with complaints had normal neurologic findings and no secondary cause for their symptoms. The included patient medical records were then reviewed for severity and duration of symptoms and the need for treatment with pain medication. Sixty-four patients underwent C2-3 RFA or TON RFA, and 12 patients were identified as experiencing ablation-induced third occipital neuralgia, an incidence rate of 19%. This finding suggests that patients undergoing RFA of the nerves supplying the C2-3 joint or TON are at risk for postprocedural third occipital neuralgia. This possibility may affect providing informed consent as well as anticipating and managing postprocedural pain. PMID:24748815

  14. The application of temporo-occipital fascial flap in the wound of medium scalp defect with bone exposure

    PubMed Central

    Wang, Jian-Li; Huang, Wen-Gang; Liu, Xing-Long

    2015-01-01

    We are aimed to observe the effect of applying the combined temporo-occipital fascial flap in the medium scalp defect with bone exposure. Three cases of moderate scalp defect with bone exposure were admitted by The 89th Hospital of PLA and China-Japan Friendship Hospital from October 2009 to March 2014, and the wounds were repaired by application of the temporo-occipital fascial flap with medium-thickness skin grafting. And then these 3 patients were followed up after the operation, and the wound repair was observed. These 3 cases of fascial flaps all survived well with good appearance and covered the wound completely. Fibrosarcoma of one case had a relapse 3 months after operation, and the other two cases were followed up from 6 months to 3 years. Meanwhile, the appearance and function were satisfactory. The communicating branches between superficial temporal artery and occipital artery are rich. Therefore we designed and utilized the long temporo-occipital fascial flap containing the ipsilateral occipital superficial fascia to repair the scalp defect with bone exposure, and the curative effect is satisfactory. PMID:26550384

  15. Distinctive Menkes disease variant with occipital horns: Delineation of natural history and clinical phenotype

    SciTech Connect

    Proud, V.K.; Mussell, H.G.; Percy, A.K.

    1996-10-02

    To delineate further the clinical spectrum of Menkes disease, an X-linked recessive disorder of copper transport, we studied 4 related males, ranging in age from 4-38 years, with a unique phenotype that combines manifestations of classical and mild Menkes disease and occipital horn syndrome (OHS). The propositus, an 18-year-old man, was evaluated following an intracerebral hemorrhage at age 15 years and was noted to have marked hypotonia, motor delay with mental retardation, bladder diverticula, failure to thrive, and diarrhea from infancy; seizures from age 3 years; and abnormal hair (pili torti) and face, cutis laxa, and multiple joint dislocations. Radiographic abnormalities included occipital exostoses, tortuous cerebral blood vessels with multiple branch occlusions, and hammer-shaped clavicles. Biochemical studies demonstrated reduced copper and ceruloplasmin levels in serum, and abnormal plasma catecholamine ratios. We reported previously the molecular defect in this family, a splice-site mutation that predicts formation of approximately 20% of the normal Menkes gene product. Here, we detail the clinical course and physical features and radiographic findings in these 4 individuals, and compare their phenotype with classical and mild Menkes and OHS. Unusual Menkes disease variants such as this may escape recognition due to anomalies that appear inconsistent with the diagnosis, particularly prolonged survival and later onset of seizures. Males with mental retardation and connective tissue abnormalities should be evaluated for biochemical evidence of defective copper transport. 28 refs., 8 figs.

  16. Reduced Resting-State Functional Connectivity of the Somatosensory Cortex Predicts Psychopathological Symptoms in Women with Bulimia Nervosa

    PubMed Central

    Lavagnino, Luca; Amianto, Federico; D’Agata, Federico; Huang, Zirui; Mortara, Paolo; Abbate-Daga, Giovanni; Marzola, Enrica; Spalatro, Angela; Fassino, Secondo; Northoff, Georg

    2014-01-01

    Background: Alterations in the resting-state functional connectivity (rs-FC) of several brain networks have been demonstrated in eating disorders. However, very few studies are currently available on brain network dysfunctions in bulimia nervosa (BN). The somatosensory network is central in processing body-related stimuli and it may be altered in BN. The present study therefore aimed to investigate rs-FC in the somatosensory network in bulimic women. Methods: Sixteen medication-free women with BN (age?=?23?±?5?years) and 18 matched controls (age?=?23?±?3?years) underwent a functional magnetic resonance resting-state scan and assessment of eating disorder symptoms. Within-network and seed-based functional connectivity analyses were conducted to assess rs-FC within the somatosensory network and to other areas of the brain. Results: Bulimia nervosa patients showed a decreased rs-FC both within the somatosensory network (t?=?9.0, df?=?1, P?=?0.005) and with posterior cingulate cortex and two visual areas (the right middle occipital gyrus and the right cuneus) (P?=?0.05 corrected for multiple comparison). The rs-FC of the left paracentral lobule with the right middle occipital gyrus correlated with psychopathology measures like bulimia (r?=??0.4; P?=?0.02) and interoceptive awareness (r?=??0.4; P?=?0.01). Analyses were conducted using age, BMI (body mass index), and depressive symptoms as covariates. Conclusion: Our findings show a specific alteration of the rs-FC of the somatosensory cortex in BN patients, which correlates with eating disorder symptoms. The region in the right middle occipital gyrus is implicated in body processing and is known as extrastriate body area (EBA). The connectivity between the somatosensory cortex and the EBA might be related to dysfunctions in body image processing. The results should be considered preliminary due to the small sample size. PMID:25136302

  17. A BOLD signature of eyeblinks in the visual cortex.

    PubMed

    Hupé, Jean-Michel; Bordier, Cécile; Dojat, Michel

    2012-05-15

    We are usually unaware of the brief but large illumination changes caused by blinks, presumably because of blink suppression mechanisms. In fMRI however, increase of the BOLD signal was reported in the visual cortex, e.g. during blocks of voluntary blinks (Bristow, Frith and Rees, 2005) or after spontaneous blinks recorded during the prolonged fixation of a static stimulus (Tse, Baumgartner and Greenlee, 2010). We tested whether such activation, possibly related to illumination changes, was also present during standard fMRI retinotopic and visual experiments and was large enough to contaminate the BOLD signal we are interested in. We monitored in a 3T scanner the eyeblinks of 14 subjects who observed three different types of visual stimuli, including periodic rotating wedges and contracting/expanding rings, event-related Mondrians and graphemes, while fixating. We performed event-related analyses on the set of detected spontaneous blinks. We observed large and widespread BOLD responses related to blinks in the visual cortex of every subject and whatever the visual stimulus. The magnitude of the modulation was comparable to visual stimulation. However, blink-related activations lay mostly in the anterior parts of retinotopic visual areas, coding the periphery of the visual field well beyond the extent of our stimuli. Blinks therefore represent an important source of BOLD variations in the visual cortex and a troublesome source of noise since any correlation, even weak, between the distribution of blinks and a tested protocol could trigger artifactual activities. However, the typical signature of blinks along the anterior calcarine and the parieto-occipital sulcus allows identifying, even in the absence of eyetracking, fMRI protocols possibly contaminated by a heterogeneous distribution of blinks. PMID:22426351

  18. The neural representation of Arabic digits in visual cortex

    PubMed Central

    Peters, Lien; De Smedt, Bert; Op de Beeck, Hans P.

    2015-01-01

    In this study, we investigated how Arabic digits are represented in the visual cortex, and how their representation changes throughout the ventral visual processing stream, compared to the representation of letters. We probed these questions with two functional magnetic resonance imaging (fMRI) experiments. In Experiment 1, we explored whether we could find brain regions that were more activated for digits than for number words in a subtraction task. One such region was detected in lateral occipital cortex. However, the activity in this region might have been confounded by string length—number words contain more characters than digits. We therefore conducted a second experiment in which string length was systematically controlled. Experiment 2 revealed that the findings of the first experiment were task dependent (as it was only observed in a task in which numerosity was relevant) or stimulus dependent (as it was only observed when the number of characters of a stimulus was not controlled). We further explored the characteristics of the activation patterns for digit and letter strings across the ventral visual processing stream through multi-voxel pattern analyses. We found an alteration in representations throughout the ventral processing stream from clustering based on amount of visual information in primary visual cortex (V1) towards clustering based on symbolic stimulus category higher in the visual hierarchy. The present findings converge to the conclusion that in the ventral visual system, as far as can be detected with fMRI, the distinction between Arabic digits and letter strings is represented in terms of distributed patterns rather than separate regions. PMID:26441613

  19. 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

  20. Phosphene Perception Relates to Visual Cortex Glutamate Levels and Covaries with Atypical Visuospatial Awareness.

    PubMed

    Terhune, Devin B; Murray, Elizabeth; Near, Jamie; Stagg, Charlotte J; Cowey, Alan; Cohen Kadosh, Roi

    2015-11-01

    Phosphenes are illusory visual percepts produced by the application of transcranial magnetic stimulation to occipital cortex. Phosphene thresholds, the minimum stimulation intensity required to reliably produce phosphenes, are widely used as an index of cortical excitability. However, the neural basis of phosphene thresholds and their relationship to individual differences in visual cognition are poorly understood. Here, we investigated the neurochemical basis of phosphene perception by measuring basal GABA and glutamate levels in primary visual cortex using magnetic resonance spectroscopy. We further examined whether phosphene thresholds would relate to the visuospatial phenomenology of grapheme-color synesthesia, a condition characterized by atypical binding and involuntary color photisms. Phosphene thresholds negatively correlated with glutamate concentrations in visual cortex, with lower thresholds associated with elevated glutamate. This relationship was robust, present in both controls and synesthetes, and exhibited neurochemical, topographic, and threshold specificity. Projector synesthetes, who experience color photisms as spatially colocalized with inducing graphemes, displayed lower phosphene thresholds than associator synesthetes, who experience photisms as internal images, with both exhibiting lower thresholds than controls. These results suggest that phosphene perception is driven by interindividual variation in glutamatergic activity in primary visual cortex and relates to cortical processes underlying individual differences in visuospatial awareness. PMID:25725043

  1. Representational Similarity of Body Parts in Human Occipitotemporal Cortex.

    PubMed

    Bracci, Stefania; Caramazza, Alfonso; Peelen, Marius V

    2015-09-23

    Regions in human lateral and ventral occipitotemporal cortices (OTC) respond selectively to pictures of the human body and its parts. What are the organizational principles underlying body part responses in these regions? Here we used representational similarity analysis (RSA) of fMRI data to test multiple possible organizational principles: shape similarity, physical proximity, cortical homunculus proximity, and semantic similarity. Participants viewed pictures of whole persons, chairs, and eight body parts (hands, arms, legs, feet, chests, waists, upper faces, and lower faces). The similarity of multivoxel activity patterns for all body part pairs was established in whole person-selective OTC regions. The resulting neural similarity matrices were then compared with similarity matrices capturing the hypothesized organizational principles. Results showed that the semantic similarity model best captured the neural similarity of body parts in lateral and ventral OTC, which followed an organization in three clusters: (1) body parts used as action effectors (hands, feet, arms, and legs), (2) noneffector body parts (chests and waists), and (3) face parts (upper and lower faces). Whole-brain RSA revealed, in addition to OTC, regions in parietal and frontal cortex in which neural similarity was related to semantic similarity. In contrast, neural similarity in occipital cortex was best predicted by shape similarity models. We suggest that the semantic organization of body parts in high-level visual cortex relates to the different functions associated with the three body part clusters, reflecting the unique processing and connectivity demands associated with the different types of information (e.g., action, social) different body parts (e.g., limbs, faces) convey. Significance statement: While the organization of body part representations in motor and somatosensory cortices has been well characterized, the principles underlying body part representations in visual cortex have not yet been explored. In the present fMRI study we used multivoxel pattern analysis and representational similarity analysis to characterize the organization of body maps in human occipitotemporal cortex (OTC). Results indicate that visual and shape dimensions do not fully account for the organization of body part representations in OTC. Instead, the representational structure of body maps in OTC appears strongly related to functional-semantic properties of body parts. We suggest that this organization reflects the unique processing and connectivity demands associated with the different types of information different body parts convey. PMID:26400929

  2. 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

  3. Monkey brain cortex imaging by photoacoustic tomography

    E-print Network

    Yang, Xinmai; Wang, Lihong V.

    2008-08-20

    Photoacoustic tomography (PAT) is applied to image the brain cortex of a monkey through the intact scalp and skull ex vivo. The reconstructed PAT image shows the major blood vessels on the monkey brain cortex. For comparison, the brain cortex...

  4. Giant Prolactinoma Presenting with Neck Pain and Structural Compromise of the Occipital Condyles

    PubMed Central

    Yecies, Derek; Ajlan, Abdulrazag; Ratliff, John; Ziskin, Jennifer; Hwang, Peter; Vogel, Hannes; Katznelson, Laurence; Harsh, Griffith

    2015-01-01

    Prolactinomas are the most common form of endocrinologically active pituitary adenoma; they account for ? 45% of pituitary adenomas encountered in clinical practice. Giant adenomas are those?>?4 cm in diameter. Less than 0.5% of pituitary adenomas encountered in neurosurgical practice are giant prolactinomas. Patients with giant prolactinomas typically present with highly elevated prolactin levels, endocrinologic disturbances, and neurologic symptoms from mass-induced pressure. Described here is an unusual case of a giant prolactinoma presenting with neck pain and structural compromise of the occipital condyles. Transnasal biopsy of the nasopharyngeal portion of the mass obtained tissue consistent with an atypical prolactinoma with p53 reactivity and a high Ki-67 index of 5%. Despite the size and invasiveness of the tumor, the patient had resolution of his clinical symptoms, dramatic reduction of his hyperprolactinemia, and near-complete disappearance of his tumor following medical treatment. PMID:26623246

  5. Chiari I malformation associated with atlanto-occipital assimilation presenting as orthopnea and cough syncope.

    PubMed

    Mangubat, Erwin Zeta; Wilson, Tom; Mitchell, Brian A; Byrne, Richard W

    2014-02-01

    Although it is not uncommon for patients with Chiari I malformations to present with respiratory complaints, cough syncope is a rare presenting symptom. We report an adult patient who had both a Chiari I malformation and atlanto-occipital assimilation, and complained of cough syncope, orthopnea, and central sleep apnea. The patient underwent decompressive craniectomy of the posterior fossa and a cervical level 2 laminectomy. However, due to an initial under-appreciation of the profound narrowing of the foramen magnum as a result of these concomitant pathologies, the patient had continued impaired cerebrospinal fluid flow, leading to a symptomatic pseudomeningocele and required a more extensive decompression that included a cervical level 3 laminectomy as well as a temporary lumbar drain. On 2 year follow-up, he remained asymptomatic. PMID:24080068

  6. 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…

  7. APFiLoc: An Infrastructure-Free Indoor Localization Method Fusing Smartphone Inertial Sensors, Landmarks and Map Information.

    PubMed

    Shang, Jianga; Gu, Fuqiang; Hu, Xuke; Kealy, Allison

    2015-01-01

    The utility and adoption of indoor localization applications have been limited due to the complex nature of the physical environment combined with an increasing requirement for more robust localization performance. Existing solutions to this problem are either too expensive or too dependent on infrastructure such as Wi-Fi access points. To address this problem, we propose APFiLoc-a low cost, smartphone-based framework for indoor localization. The key idea behind this framework is to obtain landmarks within the environment and to use the augmented particle filter to fuse them with measurements from smartphone sensors and map information. A clustering method based on distance constraints is developed to detect organic landmarks in an unsupervised way, and the least square support vector machine is used to classify seed landmarks. A series of real-world experiments were conducted in complex environments including multiple floors and the results show APFiLoc can achieve 80% accuracy (phone in the hand) and around 70% accuracy (phone in the pocket) of the error less than 2 m error without the assistance of infrastructure like Wi-Fi access points. PMID:26516858

  8. APFiLoc: An Infrastructure-Free Indoor Localization Method Fusing Smartphone Inertial Sensors, Landmarks and Map Information

    PubMed Central

    Shang, Jianga; Gu, Fuqiang; Hu, Xuke; Kealy, Allison

    2015-01-01

    The utility and adoption of indoor localization applications have been limited due to the complex nature of the physical environment combined with an increasing requirement for more robust localization performance. Existing solutions to this problem are either too expensive or too dependent on infrastructure such as Wi-Fi access points. To address this problem, we propose APFiLoc—a low cost, smartphone-based framework for indoor localization. The key idea behind this framework is to obtain landmarks within the environment and to use the augmented particle filter to fuse them with measurements from smartphone sensors and map information. A clustering method based on distance constraints is developed to detect organic landmarks in an unsupervised way, and the least square support vector machine is used to classify seed landmarks. A series of real-world experiments were conducted in complex environments including multiple floors and the results show APFiLoc can achieve 80% accuracy (phone in the hand) and around 70% accuracy (phone in the pocket) of the error less than 2 m error without the assistance of infrastructure like Wi-Fi access points. PMID:26516858

  9. Published online 30 July 2002 Functional measurements of human ventral occipital

    E-print Network

    Wandell, Brian A.

    ; visual cortex; cerebral achromatopsia; V4; V8 1. INTRODUCTION In his insightful review of the neurological literature on cerebral achromatopsia and colour anomia, Meadows (1974) argued that several structure of the pho- topic pathways, in which cones dominate the central two degrees of the fovea

  10. Simultaneous TMS-fMRI of the Visual Cortex Reveals Functional Network, Even in Absence of Phosphene Sensation

    PubMed Central

    Caparelli, E.C.; Backus, W.; Telang, F.; Wang, G-J; Maloney, T.; Goldstein, R.Z.; Anschel, D.; Henn, F.

    2010-01-01

    Phosphene sensation is commonly used to measure cortical excitability during transcranial magnetic stimulation (TMS) of the occipital cortex. However, some individuals lack this perception, and the reason for it is still unknown. In this work, we used functional magnetic resonance imaging (fMRI) to detect brain activation during local TMS of the occipital cortex in twelve healthy subjects. We found that TMS modulated brain activity in areas connected to the stimulation site, even in people unable to see phosphene. However, we observed a trend for a lower blood-oxygenation-level dependent (BOLD) signal, and smaller brain-activation clusters near the stimulated site than in the interconnected brain areas, suggesting that TMS pulse is more effective downstream than at its application site. Furthermore, we noted prominent differences in brain activation/deactivation patterns between subjects who perceived phosphene and those who did not, implying a functional distinction in their neuronal networks that might explain the origin of differences in phosphene generation. PMID:21686319

  11. Univariate frontoparietal BOLD does not track the magnitude of attentional modulations in visual cortex.

    PubMed

    Smith, Mary; Sprague, Thomas; Serences, John

    2015-09-01

    Directing attention to a region of visual space facilitates the processing of relevant sensory information, resulting in increased neural and BOLD activity in areas of the brain that process this sensory information. This process is thought to be mediated by a frontoparietal "attentional control" network that biases processing in visual cortex. Electrical microstimulation of frontal area FEF in macaques selectively enhances responses in area V4, and also leads to improved behavior (Moore, Fallah 2001, 2004; Armstrong, Moore 2007). If frontoparietal regions such as the FEF are responsible for the differential modulations in early visual cortex across time, then the magnitude of frontoparietal activity should track the magnitude of attentional modulations in early visual cortex on a trial-by-trial basis. Here, we attempted to test this hypothesis using fMRI. Participants directed spatial attention to either the left or right visual field on each trial while performing a demanding spatial attention task. Consistent with previous data, we found that frontoparietal responses were high when early visual responses were high across trials (i.e. an overall yoking between frontoparietal and occipital regions). In addition, visual areas in the hemisphere contralateral to the attended stimulus showed reliably larger BOLD responses compared to areas in the ipsilateral hemisphere. We compared the magnitude of frontoparietal activity and the differential activity in visual areas contra and ipsilateral to the attended stimulus. However, we found no evidence that the overall magnitude of responses in frontoparietal regions track the magnitude of differential attentional responses in early visual cortex. These findings indicate that the univariate magnitude in frontoparietal ROIs is not related to the magnitude of attention effects in visual cortex, at least as measured with the BOLD signal. Meeting abstract presented at VSS 2015. PMID:26326739

  12. Aversive learning shapes neuronal orientation tuning in human visual cortex

    PubMed Central

    McTeague, Lisa M.; Gruss, L. Forest; Keil, Andreas

    2015-01-01

    The responses of sensory cortical neurons are shaped by experience. As a result perceptual biases evolve, selectively facilitating the detection and identification of sensory events that are relevant for adaptive behaviour. Here we examine the involvement of human visual cortex in the formation of learned perceptual biases. We use classical aversive conditioning to associate one out of a series of oriented gratings with a noxious sound stimulus. After as few as two grating-sound pairings, visual cortical responses to the sound-paired grating show selective amplification. Furthermore, as learning progresses, responses to the orientations with greatest similarity to the sound-paired grating are increasingly suppressed, suggesting inhibitory interactions between orientation-selective neuronal populations. Changes in cortical connectivity between occipital and fronto-temporal regions mirror the changes in visuo-cortical response amplitudes. These findings suggest that short-term behaviourally driven retuning of human visual cortical neurons involves distal top–down projections as well as local inhibitory interactions. PMID:26215466

  13. Normal repetition probability effects in the occipito-temporal cortex in Schizophrenia.

    PubMed

    Grotheer, Mareike; Nenadic, Igor; Münke, Lisa; Kéri, Szabolcs; Kovács, Gyula

    2015-09-01

    A growing body of evidences suggests that the comparison of expected and incoming sensory stimuli (predictive error (PE) processing) is impaired in schizophrenia (SZ). For example in studies of mismatch negativity, an ERP component that signals PE, SZ patients show deficits in both the auditory (Fulham et al., 2014) and the visual (Neuhaus, Brandt, Goldberg, Bates, & Malhotra, 2013) modality. In order to test the role of impaired PE processing in SZ further, using neuroimaging methods, we applied a repetition suppression (RS) paradigm (Summerfield, Trittschuh, Monti, Mesulam, & Egner, 2008). 17 patients diagnosed with SZ according to DSM-IV-R / DSM V as well as 17 age and gender matched healthy control (HC) subjects were presented with pairs of faces which could either repeat or alternate. Additionally, the likelihood of repetition/alternation trials was modulated in individual blocks of fMRI recordings, testing the effects of repetition probability (P(rep)) on RS. We found a significant RS in the fusiform and occipital face areas, as well as in the lateral occipital cortex that was similar in both groups. More importantly, we observed similar P(rep) effects (significant RS in blocks with high repetition likelihood but not in blocks with low repetition likelihood) in both groups as well. Crucially, this suggests normal predictive processes in patients with Schizophrenia. Meeting abstract presented at VSS 2015. PMID:26326881

  14. The response of face-selective cortex with single face parts and part combinations

    PubMed Central

    Dachille, Lindsay R.; Gold, Jason M.; James, Thomas W.

    2012-01-01

    A critical issue in object recognition research is how the parts of an object are analyzed by the visual system and combined into a perceptual whole. However, most of the previous research has examined how changes to object parts influence recognition of the whole, rather than recognition of the parts themselves. This is particularly true of the research on face recognition, and especially with questions related to the neural substrates. Here, we investigated patterns of BOLD fMRI brain activation with internal face parts (features) presented singly and in different combinations. A preference for single features over combinations was found in the occipital face area (OFA) as well as a preference for the two-eyes combination stimulus over other combination stimulus types. The fusiform face area (FFA) and lateral occipital cortex (LO) showed no preferences among the single feature and combination stimulus types. The results are consistent with a growing view that the OFA represents processes involved in early, feature-based analysis. PMID:22750118

  15. Changing tune in auditory cortex

    PubMed Central

    Castro, Jason B; Kandler, Karl

    2010-01-01

    Investigating the organization of tone representation in the rodent auditory cortex at high resolution, two new studies in this issue find that the arrangement of relative frequency responsiveness is not preserved at a fine-scale cortical level. PMID:20177415

  16. Auditory Cortex: Representation through Sparsification?

    PubMed Central

    Willmore, Ben D.B.; King, Andrew J.

    2015-01-01

    Summary The recent discovery of combination-sensitive neurons in the primary auditory cortex of awake marmosets may reconcile previous, apparently contradictory, findings that cortical neurons produce strong, sustained responses, but also represent stimuli sparsely. PMID:20064424

  17. Suppression of diaphragmatic activity during spontaneous ponto-geniculo-occipital waves in cat.

    PubMed

    Dunin-Barkowski, W L; Orem, J M

    1998-11-01

    It has been reported that spontaneous ponto-geniculo-occipital (PGO) waves, which occur during REM sleep in the cat, are associated with a brief inhibition of diaphragmatic activity (Orem, 1980). This report was preliminary and not supported by a detailed analysis. We report here analysis of the relationship between PGO waves and diaphragmatic activity based on 3073 PGO waves recorded simultaneously with diaphragmatic activity. The results show that there is indeed an inhibition of diaphragmatic activity during PGO waves. This inhibition has an amplitude up to 20% of background, and a duration (approximately 80 ms) approximately coinciding with the temporal duration of the PGO wave. In addition, we analyzed the relationships among the activity of medullary respiratory neurons, PGO waves, and diaphragmatic activity. Two neurons were observed whose relationships to diaphragmatic activity and PGO waves were consistent with the idea that they mediated the PGO-associated inhibition of diaphragmatic activity. However, the number of PGO waves involved in the analysis of the interaction between medullary respiratory neuronal activity and diaphragmatic activity was small and, although suggestive, was not conclusive. PMID:11286342

  18. 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

  19. Ultrasound-guided atlanto-occipital puncture for cerebrospinal fluid analysis on the standing horse.

    PubMed

    Depecker, M; Bizon-Mercier, C; Couroucé-Malblanc, A

    2014-01-11

    The atlanto-occipital site (AO) is convenient for retrieving an adequate volume and quality of cerebrospinal fluid (CSF) in the diagnosis of neurological disease in horses. However, general anaesthesia is not always possible for horses displaying severe neurological signs, or for economical reasons. The objectives of the present work were to determine the feasibility and safety of ultrasound-guided CSF puncture at the AO site on the standing horse. Seven horses (six healthy and one mildly ataxic) were sedated with acepromazine (0.02 mg/kg bodyweight intravenously or 0.04 mg/kg bodyweight intramuscularly) and detomidine (0.01 mg/kg bodyweight intravenously), and placed in stocks or in a recovery stall with the head kept on a headstand. Puncture was performed by ultrasonographic guidance with a parasagittal technique, as previously described, using a 20 g, 3.5 inch spinal needle. In all horses, no adverse reaction was observed when crossing the dura mater and 20 ml of CSF was rapidly retrieved without any blood contamination. Ultrasound-guided CSF puncture can be performed easily at the AO site on a healthy standing horse. Regarding the potential risk of this procedure, safety measures and close observation are essential. Further studies on a larger amount of ataxic horses are also required before considering this technique as an alternative option for CSF puncture. PMID:24225443

  20. 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. PMID:26167008

  1. 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.

  2. A New Role for LOC101928437 in Non-Syndromic Intellectual Disability: Findings from a Family-Based Association Test

    PubMed Central

    Zhou, Shaohe; Shi, Zhangyan; Cui, Meng; Li, Junlin; Ma, Zhe; Shi, Yuanyu; Zheng, Zijian; Zhang, Fuchang; Jin, Tianbo; Geng, Tingting; Chen, Chao; Guo, Yale; Zhou, Jianping; Huang, Shaoping; Guo, Xingli; Gao, Lin; Gong, Pingyuan; Gao, Xiaocai; Zhang, Kejin

    2015-01-01

    Non-syndromic intellectual disability (NSID) is mental retardation in persons of normal physical appearance who have no recognisable features apart from obvious deficits in intellectual functioning and adaptive ability; however, its genetic etiology of most patients has remained unknown. The main purpose of this study was to fine map and identify specific causal gene(s) by genotyping a NSID family cohort using a panel of markers encompassing a target region reported in a previous work. A total of 139 families including probands, parents and relatives were included in the household survey, clinical examinations and intelligence tests, recruited from the Qinba mountain region of Shannxi province, western China. A collection of 34 tagged single nucleotide polymorphisms (tSNPs) spanning five microsatellite marker (STR) loci were genotyped using an iPLEX Gold assay. The association between tSNPs and patients was analyzed by family-based association testing (FBAT) and haplotype analysis (HBAT). Four markers (rs5974392, rs12164331, rs5929554 and rs3116911) in a block that showed strong linkage disequilibrium within the first three introns of the LOC101928437 locus were found to be significantly associated with NSID (all P<0.01) by the FBAT method for a single marker in additive, dominant and recessive models. The results of haplotype tests of this block also revealed a significant association with NSID (all P<0.05) using 2-window and larger HBAT analyses. These results suggest that LOC101928437 is a novel candidate gene for NSID in Han Chinese individuals of the Qinba region of China. Although the biological function of the gene has not been well studied, knowledge about this gene will provide insights that will increase our understanding of NSID development. PMID:26287547

  3. 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

  4. Ultrasound-guided bilateral greater occipital nerve block for the treatment of post-dural puncture headache

    PubMed Central

    Akyol, Fethi; Binici, Orhan; Kuyrukluyildiz, Ufuk; Karabakan, Guldane

    2015-01-01

    Background and Objective: Post-dural puncture headache (PDPH) is one of the complications frequently observed after spinal or epidural anesthesia with dural penetration. For PDPH patients who do not respond to conservative medical treatment, alternative treatments such as bilateral occipital nerve block should be considered.In this study the efficacy of bilateral occipital nerve block was retrospectively evaluated in patients with post-dural puncture headache. Methods: Ultrasound-guided bilateral occipital nerve block was administrated in 21 patients who developed PDPH after spinal anesthesia, but did not respond to conservative medical treatment within 48 hours between January 2012 and February 2014. The study was conducted at Erzincan University Faculty of Medicine Gazi Mengucek Education and Research Hospital Results: Mean Visual Analog Scale (VAS) pain scores at 10 minutes and 6, 10, 15 and 24 hours after the block were significantly improved compared to the patients with a pre-block VAS score between 4 and 6 as well as patients with a pre-block VAS score between 7 and 9 (p<0.01). After 24 hours of the block applied, VAS pain score dropped to 1 for all 12 patients who had a pre-block VAS score between 4 and 6. Whereas, VAS score decreased to 2 at 24 hours after the block in only one of the patients with a pre-block VAS between 7 and 9. For the patients with a pre-block VAS score between 7 and 9, there was no significant improvement in the mean VAS score 24 hours after the block. Conclusions: For patients with PDPH and a pre-block VAS score between 4 and 6 who do not respond to conservative medical treatment, an ultrasound-guided bilateral occipital nerve block may be effective. PMID:25878625

  5. Quantitative assessment of diffuse optical tomography sensitivity to the cerebral cortex using a whole-head probe

    PubMed Central

    Perdue, Katherine L; Fang, Qianqian; Diamond, Solomon G

    2012-01-01

    We quantify the variability in diffuse optical tomography (DOT) sensitivity over the cortical surface in eight young adult subjects. We use the 10/5 electroencephalography system as a basis for our whole-head optical high-density probe design. The contrast-to-noise ratio (CNR) is calculated along with the percentage of the cortex that is above a CNR=0 dB threshold. We also quantify the effect of including vasculature on the forward model and list our assumptions that allow us to estimate light penetration depth in the head. We show that using the 10/5 system for optical probe design allows for measurement of 37% of the cortical surface on average, with a mean CNR in the visible region of 5.5 dB. Certain anatomical regions, such as the lateral occipital cortex, had a very high percentage above the CNR threshold, while other regions such as the cingulate cortex were not measurable. Vasculature blocked optical sensitivity over 1% of the cortex. Cortical coverage was positively correlated with intracranial volume and relative cerebrospinal fluid volume, and negatively correlated with relative scalp volume and skull volume. These contributions allow experimenters to understand how anatomical variation in a subject population may impact DOT or functional near-infrared spectroscopy measurements. PMID:22513789

  6. Quantitative assessment of diffuse optical tomography sensitivity to the cerebral cortex using a whole-head probe

    NASA Astrophysics Data System (ADS)

    Perdue, Katherine L.; Fang, Qianqian; Diamond, Solomon G.

    2012-05-01

    We quantify the variability in diffuse optical tomography (DOT) sensitivity over the cortical surface in eight young adult subjects. We use the 10/5 electroencephalography system as a basis for our whole-head optical high-density probe design. The contrast-to-noise ratio (CNR) is calculated along with the percentage of the cortex that is above a CNR = 0 dB threshold. We also quantify the effect of including vasculature on the forward model and list our assumptions that allow us to estimate light penetration depth in the head. We show that using the 10/5 system for the optical probe design allows for the measurement of 37% of the cortical surface on average, with a mean CNR in the visible region of 5.5 dB. Certain anatomical regions, such as the lateral occipital cortex, had a very high percentage above the CNR threshold, while other regions such as the cingulate cortex were not measurable. Vasculature blocked optical sensitivity over 1% of the cortex. Cortical coverage was positively correlated with intracranial volume and relative cerebrospinal fluid volume, and negatively correlated with relative scalp volume and skull volume. These contributions allow experimenters to understand how anatomical variation in a subject population may impact DOT or functional near-infrared spectroscopy measurements.

  7. Surgical Treatment for Atlanto-Occipital Subluxation due to Destructive Spondyloarthropathy in a Patient Undergoing Long-Term Hemodialysis

    PubMed Central

    Murata, Yasuaki; Kato, Yoshiharu

    2015-01-01

    Destructive spondyloarthropathy (DSA) has been reported in patients undergoing long-term hemodialysis. Cervical spinal lesions, including those of the upper cervical spine, are reported to be some of the most common. To our knowledge, we report for the first time, a case of atlanto-occipital subluxation requiring surgical treatment due to severe myelopathy and nuchal pain in a patient undergoing long-term hemodialysis. The patient was a 66-year-old woman who had undergone hemodialysis for 40 years. She visited our hospital due to an acute progression of gait disturbance and severe nuchal pain. Computed tomography showed posterior subluxation of the atlanto-occipital joints. DSA was also observed in the lower cervical spine. Magnetic resonance imaging showed spinal canal stenosis at both the upper and lower cervical levels. We performed Oc-C7 fixation, C1 laminectomy, and C3-C7 laminoplasty. We first recognized that the atlanto-occipital subluxation was caused by the extremely long-term, in this case, 40 years, hemodialysis. PMID:26240725

  8. [An unusual case of epilepsy exhibiting gelastic seizure, simple visual hallucination, and transient swelling of the left parieto-occipital region].

    PubMed

    Kawakami, T; Takiyama, Y; Nonaka, M; Tanaka, Y; Nishizawa, M; Nakano, I

    2000-01-01

    We report a 74-year-old man with gelastic seizure, simple visual hallucination, and adversive seizure. The patient described his visual hallucinations as "rotating light like a firefly" and "mimicking a stream". Brain CT scan showed a transient swelling as well as low density of a left parieto-occipital region. Electroencephalographic study revealed spikes and fast waves beginning at left occipital region. Although temporal lobe and hypothalamic lesions (especially hypothalamic hamartomas) are well known as origins of gelastic seizures, we could not find any report that described a series of occurrence of gelastic seizure and simple visual hallucination. Usually, simple visual hallucination is thought to occur in occipital lesion. In our case, it is possible that gelastic seizure and simple visual hallucination are related to the epileptic discharge from occipital lesion directly or indirectly. The reversible brain swelling with low density seen in the present case might be caused by cytotoxic edema due to status epilepticus. PMID:10825796

  9. Visual distraction in a patient with abnormal occipital gyration - an eye-tracking study.

    PubMed

    Urgen, Buse; Demirayak, Pinar; Ustun, Fatma; Doerschner, Katja

    2015-09-01

    Maintaining focus and resisting distraction is critical for many visual tasks. We investigated these abilities in a patient with congenital abnormal bilateral occipital and parietal gyration, caused by a single gene (LAMC3) mutation. Because of the location and nature of these structural idiosyncrasies as well as compromised performance in several attention-related screening tasks we set out to measure the patient's visual attention in detail. Here, we assessed the patient's ability to maintain focus in the presence of several types of visual distractors. The patient's performance was compared to that of five sex- and education-matched healthy controls. Participants performed four eye-tracking conditions in randomized order in one experimental session: Fixation-only, Fixation with rapid sequential visual perception (RSVP), Fixation with relevant peripheral distractor (RPD), and Fixation with irrelevant peripheral distractors (IPD). Participants were required to fixate at the center and to respond when a target was detected (in RSVP, RPD, IPD). In the RPD condition relevant cues were presented for 100 ms at 8.71 degrees visual angle eccentricity in one of four possible directions, followed by a 200 ms target in the same location. In the IPD condition no cues preceded targets, everything else was as in the RPD condition. Experiments were done in MATLAB using Psychtoolbox and with an ASL Eye-Trac6 D6 Desk Mounted Optics. We measured percent correct in RSVP, RDP and IDP tasks and mean deviation from fixation in horizontal and vertical directions in all experimental conditions. Patient and control group performed comparably in behavioral tasks. Fixation results, however, indicated a decreased fixation quality of the patient in the presence of visual distractors, with deviations from fixation more than doubling (compared to controls) in RDP and IDP conditions. We discuss these results in light of the patient's structural connectivity and morphometry. Meeting abstract presented at VSS 2015. PMID:26326955

  10. Occipital Nerve Stimulation for Chronic Migraine—A Systematic Review and Meta-Analysis

    PubMed Central

    Chen, Yen-Fu; Bramley, George; Unwin, Gemma; Hanu-Cernat, Dalvina; Dretzke, Janine; Moore, David; Bayliss, Sue; Cummins, Carole; Lilford, Richard

    2015-01-01

    Background Chronic migraine is a debilitating headache disorder that has significant impact on quality of life. Stimulation of peripheral nerves is increasingly being used to treat chronic refractory pain including headache disorders. This systematic review examines the effectiveness and adverse effects of occipital nerve stimulation (ONS) for chronic migraine. Methods Databases, including the Cochrane Library, MEDLINE, EMBASE, CINAHL and clinical trial registers were searched to September 2014. Randomized controlled trials (RCTs), other controlled and uncontrolled observational studies and case series (n? 10) were eligible. RCTs were assessed using the Cochrane risk of bias tool. Meta-analysis was carried out using a random-effects model. Findings are presented in summary tables and forest plots. Results Five RCTs (total n=402) and seven case series (total n=115) met the inclusion criteria. Pooled results from three multicenter RCTs show that ONS was associated with a mean reduction of 2.59 days (95% CI 0.91 to 4.27, I2=0%) of prolonged, moderate to severe headache per month at 3 months compared with a sham control. Results for other outcomes generally favour ONS over sham controls but quantitative analysis was hampered by incomplete publication and reporting of trial data. Lead migration and infections are common and often require revision surgery. Open-label follow-up of RCTs and case series suggest long-term effectiveness can be maintained in some patients but evidence is limited. Conclusions While the effectiveness of ONS compared to sham control has been shown in multiple RCTs, the average effect size is modest and may be exaggerated by bias as achieving effective blinding remains a methodological challenge. Further measures to reduce the risk of adverse events and revision surgery are needed. Systematic Review Registration this systematic review is an update and expanded work of part of a broader review registered with PROSPERO. Registration No. CRD42012002633. PMID:25793740

  11. Premature closure of the spheno-occipital synchondrosis in Pfeiffer syndrome: a link to midface hypoplasia.

    PubMed

    Paliga, James Thomas; Goldstein, Jesse A; Vossough, Arastoo; Bartlett, Scott P; Taylor, Jesse Adam

    2014-01-01

    The spheno-occipital synchondrosis (SOS) is a critical component of midfacial and cranial base growth. Premature closure has been associated with midface hypoplasia in animal models and syndromic craniosynostosis subpopulations with Apert and Muenke syndromes. To link premature SOS closure and midface hypoplasia in patients with Pfeiffer syndrome, a retrospective case-control study was performed in patients treated at a large craniofacial center between 1982 and 2012 diagnosed with Pfeiffer syndrome. At least 1 computed tomography (CT) scan was required to assess SOS patency. Age-/sex-matched control CT scans were also assessed for SOS patency. Three independent reviewers with high interrater reliability (? = 0.88) graded SOS patency as open, partially closed, or completely closed. Wilcoxon rank sum test compared the Pfeiffer patients with control subjects. A total of 63 CT scans in 16 patients with Pfeiffer syndrome, all with midface hypoplasia, and 63 age-/sex-matched control scans, none of whom had midface hypoplasia, met inclusion criteria. Earliest partial SOS closure in patients with Pfeiffer syndrome was seen at 5 days compared with control subjects at 7.07 years. Earliest age at complete fusion was 2.76 years in the Pfeiffer cohort and 12.74 years in control subjects. Average age at partial closure was significantly younger (4.99 ± 3.33 years; n = 31 scans) in patients with Pfeiffer syndrome compared with control subjects (10.92 ± 3.53 years) (P = 0.0005), whereas average age at complete closure (11.90 ± 7.04 years) was not significantly different than that in control subjects (16.07 ± 3.39 years). Although definitive causality cannot be concluded, a strong correlation exists between midface hypoplasia and premature SOS closure in Pfeiffer syndrome. PMID:24406578

  12. Effect of prenatal protein malnutrition on long-term potentiation and BDNF protein expression in the rat entorhinal cortex after neocortical and hippocampal tetanization.

    PubMed

    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

  13. 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

  14. Feasibility of C2 Vertebra Screws Placement in Patient With Occipitalization of Atlas

    PubMed Central

    Ji, Wei; Liu, Xiang; Huang, Wenhan; Huang, Zucheng; Li, Xueshi; Chen, Jianting; Wu, Zenghui; Zhu, Qingan

    2015-01-01

    Abstract Occipitalization of atlas (OA) is a congenital disease with the possibility of anomalous bony anatomies and the C2 pedicle screw insertion is technically challenging. However, there are no existing literatures clarified the dimensions and angulations of the C2 pedicles, lamina and lateral masses for screw insertion in patients with OA. Therefore, the aim of this study was to assess the morphometric features of C2 for screw placement in OA to guide the use of surgical screws. Measurements of the OA patients on the computer tomography (CT) images including lamina angle, length and thickness, pedicle angle, length and thickness, and lateral mass thickness and length of the axis vertebra. The OA patients data were compared with age and gender matched cohort of randomly selected patients in a control group without OA. The picture archiving and communication system was used for all patients who had received cervical CT scanning between January 2001 and January 2015. Measurements were performed independently by 2 experienced observers who reviewed the CT scans and recorded the patients with OA. Statistical analysis was performed at a level of significance P?

  15. 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…

  16. 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

  17. 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

  18. 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

  19. USP38, FREM3, SDC1, DDC, and LOC727982 Gene Polymorphisms and Differential Susceptibility to Severe Malaria in Tanzania.

    PubMed

    Manjurano, Alphaxard; Sepúlveda, Nuno; Nadjm, Behzad; Mtove, George; Wangai, Hannah; Maxwell, Caroline; Olomi, Raimos; Reyburn, Hugh; Drakeley, Christopher J; Riley, Eleanor M; Clark, Taane G

    2015-10-01

    Populations exposed to Plasmodium falciparum infection develop genetic mechanisms of protection against severe malarial disease. Despite decades of genetic epidemiological research, the sickle cell trait (HbAS) sickle cell polymorphism, ABO blood group, and other hemoglobinopathies remain the few major determinants in severe malaria to be replicated across different African populations and study designs. Within a case-control study in a region of high transmission in Tanzania (n = 983), we investigated the role of 40 new loci identified in recent genome-wide studies. In 32 loci passing quality control procedures, we found polymorphisms in USP38, FREM3, SDC1, DDC, and LOC727982 genes to be putatively associated with differential susceptibility to severe malaria. Established candidates explained 7.4% of variation in severe malaria risk (HbAS polymorphism, 6.3%; ?-thalassemia, 0.3%; ABO group, 0.3%; and glucose-6-phosphate dehydrogenase deficiency, 0.5%) and the new polymorphisms, another 4.3%. The regions encompassing the loci identified are promising targets for the design of future treatment and control interventions. PMID:25805752

  20. USP38, FREM3, SDC1, DDC, and LOC727982 Gene Polymorphisms and Differential Susceptibility to Severe Malaria in Tanzania

    PubMed Central

    Manjurano, Alphaxard; Sepúlveda, Nuno; Nadjm, Behzad; Mtove, George; Wangai, Hannah; Maxwell, Caroline; Olomi, Raimos; Reyburn, Hugh; Drakeley, Christopher J.; Riley, Eleanor M.; Clark, Taane G.

    2015-01-01

    Populations exposed to Plasmodium falciparum infection develop genetic mechanisms of protection against severe malarial disease. Despite decades of genetic epidemiological research, the sickle cell trait (HbAS) sickle cell polymorphism, ABO blood group, and other hemoglobinopathies remain the few major determinants in severe malaria to be replicated across different African populations and study designs. Within a case-control study in a region of high transmission in Tanzania (n = 983), we investigated the role of 40 new loci identified in recent genome-wide studies. In 32 loci passing quality control procedures, we found polymorphisms in USP38, FREM3, SDC1, DDC, and LOC727982 genes to be putatively associated with differential susceptibility to severe malaria. Established candidates explained 7.4% of variation in severe malaria risk (HbAS polymorphism, 6.3%; ?-thalassemia, 0.3%; ABO group, 0.3%; and glucose-6-phosphate dehydrogenase deficiency, 0.5%) and the new polymorphisms, another 4.3%. The regions encompassing the loci identified are promising targets for the design of future treatment and control interventions. PMID:25805752

  1. Parietal and Frontal Cortex Encode Stimulus-Specific Mnemonic Representations during Visual Working Memory.

    PubMed

    Ester, Edward F; Sprague, Thomas C; Serences, John T

    2015-08-19

    Working memory (WM) enables the storage and manipulation of information in an active state. WM storage has long been associated with sustained increases in activation across a network of frontal and parietal cortical regions. However, recent evidence suggests that these regions primarily encode information related to general task goals rather than feature-selective representations of specific memoranda. These goal-related representations are thought to provide top-down feedback that coordinates the representation of fine-grained details in early sensory areas. Here, we test this model using fMRI-based reconstructions of remembered visual details from region-level activation patterns. We could reconstruct high-fidelity representations of a remembered orientation based on activation patterns in occipital visual cortex and in several sub-regions of frontal and parietal cortex, independent of sustained increases in mean activation. These results challenge models of WM that postulate disjoint frontoparietal "top-down control" and posterior sensory "feature storage" networks. PMID:26257053

  2. Pausing for thought: engagement of left temporal cortex during pauses in speech.

    PubMed

    Kircher, Tilo T J; Brammer, Michael J; Levelt, W; Bartels, Mathias; McGuire, Philip K

    2004-01-01

    Pauses during continuous speech, particularly those that occur within clauses, are thought to reflect the planning of forthcoming verbal output. We used functional Magnetic Resonance Imaging (fMRI) to examine their neural correlates. Six volunteers were scanned while describing seven Rorschach inkblots, producing 3 min of speech per inkblot. In an event-related design, the level of blood oxygenation level dependent (BOLD) contrast during brief speech pauses (mean duration 1.3 s, SD 0.3 s) during overt speech was contrasted with that during intervening periods of articulation. We then examined activity associated with pauses that occurred within clauses and pauses that occurred between grammatical junctions. Relative to articulation during speech, pauses were associated with activation in the banks of the left superior temporal sulcus (BA 39/22), at the temporoparietal junction. Continuous speech was associated with greater activation bilaterally in the inferior frontal (BA 44/45), middle frontal (BA 8) and anterior cingulate (BA 24) gyri, the middle temporal sulcus (BA 21/22), the occipital cortex and the cerebellum. Left temporal activation was evident during pauses that occurred within clauses but not during pauses at grammatical junctions. In summary, articulation during continuous speech involved frontal, temporal and cerebellar areas, while pausing was associated with activity in the left temporal cortex, especially when this occurred within a clause. The latter finding is consistent with evidence that within-clause pauses are a correlate of speech planning and in particular lexical retrieval. PMID:14741645

  3. Specific EEG Sleep Pattern in the Prefrontal Cortex in Primary Insomnia

    PubMed Central

    Perrier, Joy; Clochon, Patrice; Bertran, Françoise; Couque, Colette; Bulla, Jan; Denise, Pierre; Bocca, Marie-Laure

    2015-01-01

    Objective To assess the specific prefrontal activity in comparison to those in the other main cortical areas in primary insomnia patients and in good sleepers. Methods Fourteen primary insomnia patients and 11 good sleepers were included in the analysis. Participants completed one night of polysomnography in the sleep lab. Power spectra were calculated during the NREM (Non-rapid eyes movements) and the REM (Rapid eyes movements) sleep periods at prefrontal, occipital, temporal and central electrode positions. Results During the NREM sleep, the power spectra did not differ between groups in the prefrontal cortex; while primary insomnia patients exhibited a higher beta power spectrum and a lower delta power spectrum compared to good sleepers in other areas. During the REM sleep, the beta1 power spectrum was lower in the prefrontal cortex in primary insomnia patients compared to good sleepers; while no significant difference between groups was obtained for the other areas. Conclusions The present study shows a specific prefrontal sleep pattern during the whole sleep period. In addition, we suggest that primary insomnia patients displayed a dysfunction in the reactivation of the limbic system during the REM sleep and we give additional arguments in favor of a sleep-protection mechanism displayed by primary insomnia patients. PMID:25611059

  4. 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

  5. Dynamics of EEG Rhythms Support Distinct Visual Selection Mechanisms in Parietal Cortex: A Simultaneous Transcranial Magnetic Stimulation and EEG Study

    PubMed Central

    Spadone, Sara; Tosoni, Annalisa; Sestieri, Carlo; Romani, Gian Luca; Della Penna, Stefania; Corbetta, Maurizio

    2015-01-01

    Using repetitive transcranial magnetic stimulation (rTMS), we have recently shown a functional anatomical distinction in human parietal cortex between regions involved in maintaining attention to a location [ventral intraparietal sulcus (vIPS)] and a region involved in shifting attention between locations [medial superior parietal lobule (mSPL)]. In particular, while rTMS interference over vIPS impaired target discrimination at contralateral attended locations, interference over mSPL affected performance following shifts of attention regardless of the visual field (Capotosto et al., 2013). Here, using rTMS interference in conjunction with EEG recordings of brain rhythms during the presentation of cues that indicate to either shift or maintain spatial attention, we tested whether this functional anatomical segregation involves different mechanisms of rhythm synchronization. The transient inactivation of vIPS reduced the amplitude of the expected parieto-occipital low-? (8–10 Hz) desynchronization contralateral to the cued location. Conversely, the transient inactivation of mSPL, compared with vIPS, reduced the high-? (10–12 Hz) desynchronization induced by shifting attention into both visual fields. Furthermore, rTMS induced a frequency-specific delay of task-related modulation of brain rhythms. Specifically, rTMS over vIPS or mSPL during maintenance (stay cues) or shifting (shift cues) of spatial attention, respectively, caused a delay of ? parieto-occipital desynchronization. Moreover, rTMS over vIPS during stay cues caused a delay of ? (2–4 Hz) frontocentral synchronization. These findings further support the anatomo-functional subdivision of the dorsal attention network in subsystems devoted to shifting or maintaining covert visuospatial attention and indicate that these mechanisms operate in different frequency channels linking frontal to parieto-occipital visual regions. PMID:25589765

  6. Top-down modulation in the infant brain: Learning-induced expectations rapidly affect the sensory cortex at 6 months.

    PubMed

    Emberson, Lauren L; Richards, John E; Aslin, Richard N

    2015-08-01

    Recent theoretical work emphasizes the role of expectation in neural processing, shifting the focus from feed-forward cortical hierarchies to models that include extensive feedback (e.g., predictive coding). Empirical support for expectation-related feedback is compelling but restricted to adult humans and nonhuman animals. Given the considerable differences in neural organization, connectivity, and efficiency between infant and adult brains, it is a crucial yet open question whether expectation-related feedback is an inherent property of the cortex (i.e., operational early in development) or whether expectation-related feedback develops with extensive experience and neural maturation. To determine whether infants' expectations about future sensory input modulate their sensory cortices without the confounds of stimulus novelty or repetition suppression, we used a cross-modal (audiovisual) omission paradigm and used functional near-infrared spectroscopy (fNIRS) to record hemodynamic responses in the infant cortex. We show that the occipital cortex of 6-month-old infants exhibits the signature of expectation-based feedback. Crucially, we found that this region does not respond to auditory stimuli if they are not predictive of a visual event. Overall, these findings suggest that the young infant's brain is already capable of some rudimentary form of expectation-based feedback. PMID:26195772

  7. Impact of family history of alcoholism on glutamine/glutamate ratio in anterior cingulate cortex in substance-naïve adolescents.

    PubMed

    Cohen-Gilbert, Julia E; Sneider, Jennifer T; Crowley, David J; Rosso, Isabelle M; Jensen, J Eric; Silveri, Marisa M

    2015-12-01

    Neuroimaging studies of individuals with family histories of alcoholism provide evidence suggesting neurobiological risk factors for alcoholism. Youth family history positive (FH+) for alcoholism exhibit increased impulsivity compared to family history negative (FH-) peers in conjunction with altered functional activation in prefrontal cortex, including anterior cingulate cortex (ACC). This study examined glutamate (Glu) and glutamine (Gln), amino acids vital to protein synthesis, cellular metabolism and neurotransmission, acquired from ACC and parieto-occipital cortex (POC) using magnetic resonance spectroscopy (MRS) at 4T. Participants were 28 adolescents (13 male, 12-14yrs) and 31 emerging adults (16 male, 18-25yrs), stratified into FH- and FH+ groups. Significantly higher ACC Gln/Glu was observed in emerging adults versus adolescents in FH- but not FH+ groups. In FH- adolescents, higher impulsivity was significantly associated with higher ACC Gln/Glu. In FH+ emerging adults, higher impulsivity was negatively associated with ACC Gln/Glu. No differences or associations were observed for POC. These findings provide preliminary evidence that family history of alcoholism is associated with a neurochemical profile that may influence normative age differences in glutamatergic metabolites and their association with impulse control, which together could confer greater genetic risk of addiction later in life. PMID:26025607

  8. Top-down modulation in the infant brain: Learning-induced expectations rapidly affect the sensory cortex at 6 months

    PubMed Central

    Emberson, Lauren L.; Richards, John E.; Aslin, Richard N.

    2015-01-01

    Recent theoretical work emphasizes the role of expectation in neural processing, shifting the focus from feed-forward cortical hierarchies to models that include extensive feedback (e.g., predictive coding). Empirical support for expectation-related feedback is compelling but restricted to adult humans and nonhuman animals. Given the considerable differences in neural organization, connectivity, and efficiency between infant and adult brains, it is a crucial yet open question whether expectation-related feedback is an inherent property of the cortex (i.e., operational early in development) or whether expectation-related feedback develops with extensive experience and neural maturation. To determine whether infants’ expectations about future sensory input modulate their sensory cortices without the confounds of stimulus novelty or repetition suppression, we used a cross-modal (audiovisual) omission paradigm and used functional near-infrared spectroscopy (fNIRS) to record hemodynamic responses in the infant cortex. We show that the occipital cortex of 6-month-old infants exhibits the signature of expectation-based feedback. Crucially, we found that this region does not respond to auditory stimuli if they are not predictive of a visual event. Overall, these findings suggest that the young infant’s brain is already capable of some rudimentary form of expectation-based feedback. PMID:26195772

  9. Endoscopic-assisted interhemispheric parieto-occipital transtentorial approach for microsurgical resection of a pineal region tumor: operative video and technical nuances.

    PubMed

    Liu, James K

    2016-01-01

    The angle of the straight sinus and tentorium cerebelli can often influence the choice of surgical approach to the pineal region. The supracerebellar infratentorial approach can be technically challenging and a relative contraindication in cases where the angle of the straight sinus and tentorium is very steep. Similarly, an occipital transtentorial approach, which uses a low occipital craniotomy at the junction of the superior sagittal sinus and transverse sinus, may not provide the best trajectory to the pineal region in patients with a steep tentorium. In addition, this approach often necessitates retraction on the occipital lobe to access the tentorial incisura and pineal region, which can increase the risk of visual compromise. In this operative video, the author demonstrates an alternative route using an endoscopic-assisted interhemispheric parieto-occipital transtentorial approach to a pineal region tumor in a patient with a steep straight sinus and tentorium. The approach provided a shorter route and more direct trajectory to the tumor at the tentorial incisura, and avoided direct fixed retraction on the occipital lobe when performed using the lateral position, thereby minimizing visual complications. This video atlas demonstrates the operative technique and surgical nuances, including the application of endoscopic-assisted microsurgical resection and operative pearls for preservation of the deep cerebral veins. In summary, the parieto-occipital transtentorial approach with endoscopic assistance is an important approach in the armamentarium for surgical management of pineal region tumors. The video can be found here: https://youtu.be/Ph4veG14aTk . PMID:26722692

  10. Frontal Eye Fields Control Attentional Modulation of Alpha and Gamma Oscillations in Contralateral Occipitoparietal Cortex

    PubMed Central

    O'Shea, Jacinta; Jensen, Ole; Bergmann, Til O.

    2015-01-01

    Covertly directing visuospatial attention produces a frequency-specific modulation of neuronal oscillations in occipital and parietal cortices: anticipatory alpha (8–12 Hz) power decreases contralateral and increases ipsilateral to attention, whereas stimulus-induced gamma (>40 Hz) power is boosted contralaterally and attenuated ipsilaterally. These modulations must be under top-down control; however, the control mechanisms are not yet fully understood. Here we investigated the causal contribution of the human frontal eye field (FEF) by combining repetitive transcranial magnetic stimulation (TMS) with subsequent magnetoencephalography. Following inhibitory theta burst stimulation to the left FEF, right FEF, or vertex, participants performed a visual discrimination task requiring covert attention to either visual hemifield. Both left and right FEF TMS caused marked attenuation of alpha modulation in the occipitoparietal cortex. Notably, alpha modulation was consistently reduced in the hemisphere contralateral to stimulation, leaving the ipsilateral hemisphere relatively unaffected. Additionally, right FEF TMS enhanced gamma modulation in left visual cortex. Behaviorally, TMS caused a relative slowing of response times to targets contralateral to stimulation during the early task period. Our results suggest that left and right FEF are causally involved in the attentional top-down control of anticipatory alpha power in the contralateral visual system, whereas a right-hemispheric dominance seems to exist for control of stimulus-induced gamma power. These findings contrast the assumption of primarily intrahemispheric connectivity between FEF and parietal cortex, emphasizing the relevance of interhemispheric interactions. The contralaterality of effects may result from a transient functional reorganization of the dorsal attention network after inhibition of either FEF. PMID:25632139

  11. Understanding the topography of face and body selectivity in human ventral temporal cortex.

    PubMed

    Chan, Annie; Silson, Edward; Baker, Chris

    2015-09-01

    Faces and body-parts are amongst the most salient visual stimuli in our environment. Research from human and non-human primates has reported multiple clusters of selectivity for faces and body-parts in the ventral visual pathway. Body-selective regions are often found close to face-selective regions, suggesting some sort of organizational principle. However, the nature of this organizational principle is not well established. Here, we investigated the topographical organization and specificity of body- and face-selective regions in visual temporal cortex at high resolution (1.2 mm isotropic voxels) using a 7T MRI scanner. First, we identified regions selective for faces and body-parts. Given prior reports of a body-part topography in lateral occipital cortex, we separately tested both hands and feet, which might be expected to have the most distinct representations. Second, we mapped population receptive fields in each participant to determine the extent to which the location of face- and body-selectivity reflect underlying retinotopic biases. Third, we tested the representational structure in face- and body-selective regions in a condition-rich event-related experiment. As expected, we found that faces elicited strong responses along the mid fusiform sulcus, in a region that has often been referred to as the Fusiform Face Area. This face selectivity coincided with a foveal representation of the visual field, while hands and feet produced robust responses adjacent and lateral to the face selectivity. We found little evidence for alternating patches of face and limb selectivity. Instead, we observed parallel streams of limb and face selectivity, extending from lateral to medial areas of the ventral cortex. Further, analysis of the representational structure of limb and face selective regions revealed striking differences. Our findings highlight the fine-grained organizational structure in ventral temporal and the importance of underlying retinotopic biases. Meeting abstract presented at VSS 2015. PMID:26326311

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

    PubMed

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

  13. Complete pattern of ocular dominance columns in human primary visual cortex.

    PubMed

    Adams, Daniel L; Sincich, Lawrence C; Horton, Jonathan C

    2007-09-26

    The occipital lobes were obtained after death from six adult subjects with monocular visual loss. Flat-mounts were processed for cytochrome oxidase (CO) to reveal metabolic activity in the primary (V1) and secondary (V2) visual cortices. Mean V1 surface area was 2643 mm2 (range, 1986-3477 mm2). Ocular dominance columns were present in all cases, having a mean width of 863 microm. There were 78-126 column pairs along the V1 perimeter. Human column patterns were highly variable, but in at least one person they resembled a scaled-up version of macaque columns. CO patches in the upper layers were centered on ocular dominance columns in layer 4C, with one exception. In this individual, the columns in a local area resembled those present in the squirrel monkey, and no evidence was found for column/patch alignment. In every subject, the blind spot of the contralateral eye was conspicuous as an oval region without ocular dominance columns. It provided a precise landmark for delineating the central 15 degrees of the visual field. A mean of 53.1% of striate cortex was devoted to the representation of the central 15 degrees. This fraction was less than the proportion of striate cortex allocated to the representation of the central 15 degrees in the macaque. Within the central 15 degrees, each eye occupied an equal territory. Beyond this eccentricity, the contralateral eye predominated, occupying 63% of the cortex. In one subject, monocular visual loss began at age 4 months, causing shrinkage of ocular dominance columns. In V2, which had a larger surface area than V1, CO stripes were present but could not be classified as thick or thin. PMID:17898211

  14. Noradrenalin and dopamine receptors both control cAMP-PKA signaling throughout the cerebral cortex

    PubMed Central

    Nomura, Shinobu; Bouhadana, Maud; Morel, Carole; Faure, Philippe; Cauli, Bruno; Lambolez, Bertrand; Hepp, Régine

    2014-01-01

    Noradrenergic fibers innervate the entire cerebral cortex, whereas the cortical distribution of dopaminergic fibers is more restricted. However, the relative functional impact of noradrenalin and dopamine receptors in various cortical regions is largely unknown. Using a specific genetic label, we first confirmed that noradrenergic fibers innervate the entire cortex whereas dopaminergic fibers were present in all layers of restricted medial and lateral areas but only in deep layers of other areas. Imaging of a genetically encoded sensor revealed that noradrenalin and dopamine widely activate PKA in cortical pyramidal neurons of frontal, parietal and occipital regions with scarce dopaminergic fibers. Responses to noradrenalin had higher amplitude, velocity and occurred at more than 10-fold lower dose than those elicited by dopamine, whose amplitude and velocity increased along the antero-posterior axis. The pharmacology of these responses was consistent with the involvement of Gs-coupled beta1 adrenergic and D1/D5 dopaminergic receptors, but the inhibition of both noradrenalin and dopamine responses by beta adrenergic antagonists was suggestive of the existence of beta1-D1/D5 heteromeric receptors. Responses also involved Gi-coupled alpha2 adrenergic and D2-like dopaminergic receptors that markedly reduced their amplitude and velocity and contributed to their cell-to-cell heterogeneity. Our results reveal that noradrenalin and dopamine receptors both control cAMP-PKA signaling throughout the cerebral cortex with moderate regional and laminar differences. These receptors can thus mediate widespread effects of both catecholamines, which are reportedly co-released by cortical noradrenergic fibers beyond the territory of dopaminergic fibers. PMID:25191229

  15. 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

  16. Occipital Artery Arising from the Anterior Aspect of the Internal Carotid Artery Identified by Three-Dimensional Computed Tomography Angiography

    PubMed Central

    Iwai, Toshinori; Izumi, Toshiharu; Inoue, Tomio; Maegawa, Jiro; Fuwa, Nobukazu; Mitsudo, Kenji; Tohnai, Iwai

    2012-01-01

    Variation of the branches of the external carotid artery (ECA) is well known, but it is extremely rare for the occipital artery (OA) to arise from the internal carotid artery (ICA). A 87-year-old man was found to have this anatomical variation on the right side by threedimensional computed tomography angiography for vascular mapping of the carotid arteries before superselective intra-arterial catheterization for advanced tongue cancer. Imaging showed the OA arose from the anterior aspect of the right ICA with the origin located 8.8 mm distal from the carotid bifurcation. The inner diameter of the origin of the OA was 2.1 mm and the angle between the OA and the ICA was 62 degrees. It is important to recognize this anatomic variation of the branches of the ECA before head and neck microsurgical reconstruction or superselective intra-arterial chemotherapy for oral cancer. PMID:23329973

  17. Paleoneurology of two new neandertal occipitals from El Sidrón (asturias, Spain) in the context of homo endocranial evolution.

    PubMed

    Peña-Melián, Angel; Rosas, Antonio; García-Tabernero, Antonio; Bastir, Markus; De La Rasilla, Marco

    2011-08-01

    The endocranial surface description and comparative analyses of two new neandertal occipital fragments (labelled SD-1149 and SD-370a) from the El Sidrón site (Asturias, Spain) reveal new aspects of neandertal brain morphological asymmetries. The dural sinus drainage pattern, as observed on the sagittal-transverse system, as well as the cerebral occipito-petalias, point out a slightly differential configuration of the neandertal brain when compared to other Homo species, especially H. sapiens. The neandertal dural sinus drainage pattern is organized in a more asymmetric mode, in such a way that the superior sagittal sinus (SSS) drains either to the right or to the left transverse sinuses, but in no case in a confluent mode (i.e. simultaneous continuation of SSS with both right (RTS) and left (LTS) transverse sinuses). Besides, the superior sagittal sinus shows an accentuated deviation from of the mid-sagittal plane in its way to the RTS in 35% of neandertals. This condition, which increases the asymmetry of the system, is almost nonexistent neither in the analyzed Homo fossil species sample nor in that of anatomically modern humans. Regarding the cerebral occipito-petalias, neandertals manifest one of the lowest percentages of left petalia of the Homo sample (including modern H. sapiens). As left occipito-petalia is the predominant pattern in hominins, it seems as if neandertals would have developed a different pattern of brain hemispheres asymmetry. Finally, the relief and position of the the cerebral sulci and gyri impressions observed in the El Sidrón occipital specimens look similar to those observed in modern H. sapiens. PMID:21714107

  18. Multimap formation in visual cortex

    PubMed Central

    Jain, Rishabh; Millin, Rachel; Mel, Bartlett W.

    2015-01-01

    An extrastriate visual area such as V2 or V4 contains neurons selective for a multitude of complex shapes, all sharing a common topographic organization. Simultaneously developing multiple interdigitated maps—hereafter a “multimap”—is challenging in that neurons must compete to generate a diversity of response types locally, while cooperating with their dispersed same-type neighbors to achieve uniform visual field coverage for their response type at all orientations, scales, etc. Previously proposed map development schemes have relied on smooth spatial interaction functions to establish both topography and columnar organization, but by locally homogenizing cells' response properties, local smoothing mechanisms effectively rule out multimap formation. We found in computer simulations that the key requirements for multimap development are that neurons are enabled for plasticity only within highly active regions of cortex designated “learning eligibility regions” (LERs), but within an LER, each cell's learning rate is determined only by its activity level with no dependence on location. We show that a hybrid developmental rule that combines spatial and activity-dependent learning criteria in this way successfully produces multimaps when the input stream contains multiple distinct feature types, or in the degenerate case of a single feature type, produces a V1-like map with “salt-and-pepper” structure. Our results support the hypothesis that cortical maps containing a fine mixture of different response types, whether in monkey extrastriate cortex, mouse V1 or elsewhere in the cortex, rather than signaling a breakdown of map formation mechanisms at the fine scale, are a product of a generic cortical developmental scheme designed to map cells with a diversity of response properties across a shared topographic space. PMID:26641946

  19. Multimap formation in visual cortex.

    PubMed

    Jain, Rishabh; Millin, Rachel; Mel, Bartlett W

    2015-12-01

    An extrastriate visual area such as V2 or V4 contains neurons selective for a multitude of complex shapes, all sharing a common topographic organization. Simultaneously developing multiple interdigitated maps-hereafter a "multimap"-is challenging in that neurons must compete to generate a diversity of response types locally, while cooperating with their dispersed same-type neighbors to achieve uniform visual field coverage for their response type at all orientations, scales, etc. Previously proposed map development schemes have relied on smooth spatial interaction functions to establish both topography and columnar organization, but by locally homogenizing cells' response properties, local smoothing mechanisms effectively rule out multimap formation. We found in computer simulations that the key requirements for multimap development are that neurons are enabled for plasticity only within highly active regions of cortex designated "learning eligibility regions" (LERs), but within an LER, each cell's learning rate is determined only by its activity level with no dependence on location. We show that a hybrid developmental rule that combines spatial and activity-dependent learning criteria in this way successfully produces multimaps when the input stream contains multiple distinct feature types, or in the degenerate case of a single feature type, produces a V1-like map with "salt-and-pepper" structure. Our results support the hypothesis that cortical maps containing a fine mixture of different response types, whether in monkey extrastriate cortex, mouse V1 or elsewhere in the cortex, rather than signaling a breakdown of map formation mechanisms at the fine scale, are a product of a generic cortical developmental scheme designed to map cells with a diversity of response properties across a shared topographic space. PMID:26641946

  20. Frontal cortex TMS for tinnitus.

    PubMed

    De Ridder, Dirk; Song, Jae-Jin; Vanneste, Sven

    2013-05-01

    Both invasive and non-invasive neuromodulation of the dorsolateral prefrontal cortex (DLPFC) are capable of suppressing tinnitus loudness. Repetitive transcranial magnetic stimulation (rTMS) of the DLPFC has an add-on effect for auditory cortex (AC) rTMS in improving tinnitus-related distress. We aimed to investigate whether TMS and rTMS of the DLPFC is capable of reducing tinnitus loudness and what mechanism might be involved. Two TMS studies targeting the right DLPFC were performed. Study 1 investigated 44 tinnitus patients who underwent either 1 or 10 Hz real or sham TMS (200 pulses at 80% motor threshold). In Study 2 we performed rTMS (10 sessions of 600 pulses) in responders of study 1. Changes on the visual analog scale (VAS) loudness were evaluated. All patients underwent a pre-TMS electroencephalography: differences in functional connectivity between responders and non-responders were evaluated using sLORETA. Only 1 Hz TMS was capable of significantly reducing tinnitus loudness for 11 patients with a mean suppression of 39.23%. RTMS for these 11 patients yielded a 21% improvement in VAS loudness, and in 7 of 11 rTMS was successful, with, a mean suppression of 27.13%. The responders were characterized by a difference in lagged linear connectivity in the theta band among the DLPFC, anterior cingulate cortex (ACC), parahippocampus and AC. In summary, 1 H, TMS and rTMS of the right DLPFC can transiently reduce the perceived tinnitus loudness mediated via functional connections between the DLPFC and a network consisting of the ACC, parahippocampus and AC. PMID:22853891

  1. Strategies: HOCs & LOCs

    E-print Network

    . Some Higher Order Concerns: Sources: Plagiarism Plagiarism is a serious offense at Duke and beyond plagiarism and be grounds for judicial review. Don't jeopardize your career at Duke: cite your sources

  2. 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

  3. On the Self-Regulation of the Occipital Alpha Rhythm: Control Strategies, States of Consciousness, and the Role of Physiological Feedback

    ERIC Educational Resources Information Center

    Plotkin, William B.

    1976-01-01

    This experiment was designed to gather data on issues corresponding to the following questions: 1. What is the relationship between the Oculomotor and Cognitive strategies of occipital alpha control? 2. Are there states of consciousness that are directly associated with alpha activity? 3. Does physiological feedback itself contribute to the…

  4. 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

    Dynamic Representation of Eye Position in the Parieto-Occipital Sulcus K. NAKAMURA, H. H. CHUNG, M 08544 Nakamura, K., H. H. Chung, M.S.A. Graziano, and C. G. Gross. Dynamic representation of eye stimulation and to the position and movement of the eyes. We examined the effects of eye position and eye

  5. 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…

  6. 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. PMID:26090471

  7. 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.

  8. 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.

  9. Distinct illusory own-body perceptions caused by damage to posterior insula and extrastriate cortex.

    PubMed

    Heydrich, Lukas; Blanke, Olaf

    2013-03-01

    Recent research in cognitive neuroscience using virtual reality, robotic technology and brain imaging has linked self-consciousness to the processing and integration of multisensory bodily signals. This work on bodily self-consciousness has implicated the temporo-parietal, premotor and extrastriate cortex and partly originated in work on neurological patients with different disorders of bodily self-consciousness. One class of such disorders is autoscopic phenomena, which are defined as illusory own-body perceptions, during which patients experience the visual illusory reduplication of their own body in extrapersonal space. Three main forms of autoscopic phenomena have been defined. During autoscopic hallucinations, a second own body is seen without any changes in bodily self-consciousness. During out-of-body experiences, the second own body is seen from an elevated perspective and location associated with disembodiment. During heautoscopy, subjects report strong self-identification with the second own body, often associated with the experience of existing at and perceiving the world from two places at the same time. Although it has been proposed that each autoscopic phenomenon is associated with different impairments of bodily self-consciousness, past research on neurological patients and the development of experimental paradigms for the study of bodily self-consciousness has focused on out-of-body experiences and the association with temporo-parietal cortex. Here, we performed quantitative lesion analysis in the-to date-largest group of patients with autoscopic hallucination and heautoscopy and compared the location of brain damage with those of control patients suffering from complex visual hallucinations. We found that heautoscopy was associated with lesions to the left posterior insula, and that autoscopic hallucinations were associated with damage to the right occipital cortex. Autoscopic hallucination and heautoscopy were further associated with distinct symptoms and deficits. The present data suggest that the autoscopic hallucination is a visuo-somatosensory deficit implicating extrastriate cortex and is, despite the visual hallucination of the own body, not associated with major deficits in bodily self-consciousness. Based on the symptoms and deficits in patients with heautoscopy and the implication of the left posterior insula, we suggest that abnormal bodily self-consciousness during heautoscopy is caused by a breakdown of self-other discrimination regarding affective somatosensory experience due to a disintegration of visuo-somatosensory signals with emotional (and/or interoceptive) bodily signals. These brain mechanisms are distinct from those described for out-of-body experiences. The present data extend previous models of autoscopic phenomena and provide clinical evidence for the importance of emotional and interoceptive signal processing in the posterior insula in relation to bodily self-consciousness. PMID:23423672

  10. 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

  11. Medial perirhinal cortex disambiguates confusable objects.

    PubMed

    Kivisaari, Sasa L; Tyler, Lorraine K; Monsch, Andreas U; Taylor, Kirsten I

    2012-12-01

    Our brain disambiguates the objects in our cluttered visual world seemingly effortlessly, enabling us to understand their significance and to act appropriately. The role of anteromedial temporal structures in this process, particularly the perirhinal cortex, is highly controversial. In some accounts, the perirhinal cortex is necessary for differentiating between perceptually and semantically confusable objects. Other models claim that the perirhinal cortex neither disambiguates perceptually confusable objects nor plays a unique role in semantic processing. One major hurdle to resolving this central debate is the fact that brain damage in human patients typically encompasses large portions of the anteromedial temporal lobe, such that the identification of individual substructures and precise neuroanatomical locus of the functional impairments has been difficult. We tested these competing accounts in patients with Alzheimer's disease with varying degrees of atrophy in anteromedial structures, including the perirhinal cortex. To assess the functional contribution of each anteromedial temporal region separately, we used a detailed region of interest approach. From each participant, we obtained magnetic resonance imaging scans and behavioural data from a picture naming task that contrasted naming performance with living and non-living things as a way of manipulating perceptual and semantic confusability; living things are more similar to one another than non-living things, which have more distinctive features. We manually traced neuroanatomical regions of interest on native-space cortical surface reconstructions to obtain mean thickness estimates for the lateral and medial perirhinal cortex and entorhinal cortex. Mean cortical thickness in each region of interest, and hippocampal volume, were submitted to regression analyses predicting naming performance. Importantly, atrophy of the medial perirhinal cortex, but not lateral perirhinal cortex, entorhinal cortex or hippocampus, significantly predicted naming performance on living relative to non-living things. These findings indicate that one specific anteromedial temporal lobe region-the medial perirhinal cortex-is necessary for the disambiguation of perceptually and semantically confusable objects. Taken together, these results support a hierarchical account of object processing, whereby the perirhinal cortex at the apex of the ventral object processing system is required to bind properties of not just perceptually, but also semantically confusable objects together, enabling their disambiguation from other similar objects and thus comprehension. Significantly, this model combining a hierarchical object processing architecture with a semantic feature statistic account explains why category-specific semantic impairments for living things are associated with anteromedial temporal lobe damage, and pinpoints the root of this syndrome to perirhinal cortex damage. PMID:23250887

  12. 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

  13. Visual areas in macaque cortex measured using functional magnetic resonance imaging.

    PubMed

    Brewer, Alyssa A; Press, William A; Logothetis, Nikos K; Wandell, Brian A

    2002-12-01

    We describe the first systematic functional magnetic resonance imaging (fMRI) measurements of visual field maps in macaque visual cortex. The boundaries of visual areas V1, V2, V3, V3A, V4, MT/V5, and TEO/V4A were identified using stimuli that create traveling waves of activity in retinotopically organized areas of the visual cortex. Furthermore, these stimuli were used to measure the dimensions of the representations of the central 11 degrees in V1-V3, quantitative visual field eccentricity functions for V1-V3 and MT, and the distribution of foveal and peripheral signals within the occipital lobe. Within areas V1, V2, MT, and portions of V4, the fMRI signals were 5-10 times the noise level (3 mm3 volumes of interest). Signals were weaker but still significant in other cortical regions, including V3, V3A, and TEO. There is good agreement between the fMRI maps and the visual area maps discovered using local anatomical and physiological measurements. The fMRI measurements allow one to obtain a broad view of the distribution of cortical signals, spanning multiple visual areas at a single point in time. The combination of scale and sensitivity demonstrated here create a good foundation for measuring how localized signals and lesions influence the responses and reorganization in widely separated cortical regions. The ability to measure human and macaque maps using the same technology will make it possible to define computational homologies between the two species. PMID:12451141

  14. 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

  15. 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

  16. Determinants of Global Color-Based Selection in Human Visual Cortex.

    PubMed

    Bartsch, Mandy V; Boehler, Carsten N; Stoppel, Christian M; Merkel, Christian; Heinze, Hans-Jochen; Schoenfeld, Mircea A; Hopf, Jens-Max

    2015-09-01

    Feature attention operates in a spatially global way, with attended feature values being prioritized for selection outside the focus of attention. Accounts of global feature attention have emphasized feature competition as a determining factor. Here, we use magnetoencephalographic recordings in humans to test whether competition is critical for global feature selection to arise. Subjects performed a color/shape discrimination task in one visual field (VF), while irrelevant color probes were presented in the other unattended VF. Global effects of color attention were assessed by analyzing the response to the probe as a function of whether or not the probe's color was a target-defining color. We find that global color selection involves a sequence of modulations in extrastriate cortex, with an initial phase in higher tier areas (lateral occipital complex) followed by a later phase in lower tier retinotopic areas (V3/V4). Importantly, these modulations appeared with and without color competition in the focus of attention. Moreover, early parts of the modulation emerged for a task-relevant color not even present in the focus of attention. All modulations, however, were eliminated during simple onset-detection of the colored target. These results indicate that global color-based attention depends on target discrimination independent of feature competition in the focus of attention. PMID:24770709

  17. Voxel-based morphometry reveals reduced grey matter volume in the temporal cortex of developmental prosopagnosics

    PubMed Central

    Furl, Nicholas; Draganski, Bogdan; Weiskopf, Nikolaus; Stevens, John; Tan, Geoffrey Chern-Yee; Driver, Jon; Dolan, Ray J.; Duchaine, Bradley

    2009-01-01

    Individuals with developmental prosopagnosia exhibit severe and lasting difficulties in recognizing faces despite the absence of apparent brain abnormalities. We used voxel-based morphometry to investigate whether developmental prosopagnosics show subtle neuroanatomical differences from controls. An analysis based on segmentation of T1-weighted images from 17 developmental prosopagnosics and 18 matched controls revealed that they had reduced grey matter volume in the right anterior inferior temporal lobe and in the superior temporal sulcus/middle temporal gyrus bilaterally. In addition, a voxel-based morphometry analysis based on the segmentation of magnetization transfer parameter maps showed that developmental prosopagnosics also had reduced grey matter volume in the right middle fusiform gyrus and the inferior temporal gyrus. Multiple regression analyses relating three distinct behavioural component scores, derived from a principal component analysis, to grey matter volume revealed an association between a component related to facial identity and grey matter volume in the left superior temporal sulcus/middle temporal gyrus plus the right middle fusiform gyrus/inferior temporal gyrus. Grey matter volume in the lateral occipital cortex was associated with component scores related to object recognition tasks. Our results demonstrate that developmental prosopagnosics have reduced grey matter volume in several regions known to respond selectively to faces and provide new evidence that integrity of these areas relates to face recognition ability. PMID:19887506

  18. Testing the dual-pathway model for auditory processing in human cortex.

    PubMed

    Zündorf, Ida C; Lewald, Jörg; Karnath, Hans-Otto

    2016-01-01

    Analogous to the visual system, auditory information has been proposed to be processed in two largely segregated streams: an anteroventral ("what") pathway mainly subserving sound identification and a posterodorsal ("where") stream mainly subserving sound localization. Despite the popularity of this assumption, the degree of separation of spatial and non-spatial auditory information processing in cortex is still under discussion. In the present study, a statistical approach was implemented to investigate potential behavioral dissociations for spatial and non-spatial auditory processing in stroke patients, and voxel-wise lesion analyses were used to uncover their neural correlates. The results generally provided support for anatomically and functionally segregated auditory networks. However, some degree of anatomo-functional overlap between "what" and "where" aspects of processing was found in the superior pars opercularis of right inferior frontal gyrus (Brodmann area 44), suggesting the potential existence of a shared target area of both auditory streams in this region. Moreover, beyond the typically defined posterodorsal stream (i.e., posterior superior temporal gyrus, inferior parietal lobule, and superior frontal sulcus), occipital lesions were found to be associated with sound localization deficits. These results, indicating anatomically and functionally complex cortical networks for spatial and non-spatial auditory processing, are roughly consistent with the dual-pathway model of auditory processing in its original form, but argue for the need to refine and extend this widely accepted hypothesis. PMID:26388552

  19. Realistic and spherical head modeling for EEG forward problem solution: a comparative cortex-based analysis.

    PubMed

    Vatta, Federica; Meneghini, Fabio; Esposito, Fabrizio; Mininel, Stefano; Di Salle, Francesco

    2010-01-01

    The accuracy of forward models for electroencephalography (EEG) partly depends on head tissues geometry and strongly affects the reliability of the source reconstruction process, but it is not yet clear which brain regions are more sensitive to the choice of different model geometry. In this paper we compare different spherical and realistic head modeling techniques in estimating EEG forward solutions from current dipole sources distributed on a standard cortical space reconstructed from Montreal Neurological Institute (MNI) MRI data. Computer simulations are presented for three different four-shell head models, two with realistic geometry, either surface-based (BEM) or volume-based (FDM), and the corresponding sensor-fitted spherical-shaped model. Point Spread Function (PSF) and Lead Field (LF) cross-correlation analyses were performed for 26 symmetric dipole sources to quantitatively assess models' accuracy in EEG source reconstruction. Realistic geometry turns out to be a relevant factor of improvement, particularly important when considering sources placed in the temporal or in the occipital cortex. PMID:20169107

  20. Lack of automatic attentional orienting by gaze cues following a bilateral loss of visual cortex.

    PubMed

    Burra, Nicolas; Kerzel, Dirk; de Gelder, Beatrice; Pegna, Alan J

    2014-05-01

    In social interactions, the location of relevant stimuli is often indicated by the orientation of gaze. It has been proposed that the direction of gaze might produce an automatic cueing of attention, similar to what is observed with exogenous cues. However, several reports have challenged this claim by demonstrating that the behavioral gain that arises with gaze cueing could be explained by shifts of attention, which are intentional and not automatic. We reasoned that if cueing by gaze was truly automatic, it should occur without awareness and should be sustained by subcortical circuits, including the amygdalae, independently of the main geniculo-striate visual pathway. We presented a cross-modal version of the Posner cueing paradigm to a patient (TN) with bilateral lesions of occipital cortex (Burra et al., 2013; Pegna, Khateb, Lazeyras, & Seghier, 2005). TN was asked to localize a sound using a key press. The location of the sound was congruent or incongruent with the direction of gaze of a face-cue. In groups of healthy young and age-matched participants, we observed significantly longer response times for incongruent than congruent sounds, suggesting that gaze direction interfered with processing of localized sounds. By contrast, TN?s performance was not affected by sound-gaze congruence. The results suggest that the processing of gaze orientation cannot occur in the absence of geniculo-striate processing, suggesting that it is not automatic. PMID:24732381

  1. [Anesthetic Management Using Frontal Nerve, Greater Occipital Nerve, and Superficial Cervical Plexus Block for Posterior Cervical Spinal Fusion in a Patient with Athetoid Cerebral Palsy].

    PubMed

    Matsunami, Sayuri; Komasawa, Nobuyasu; Fujiwara, Shunsuke; Fujitate, Yasutaka; Soen, Masako; Minami, Toshiaki

    2015-05-01

    Here, we report successful anesthetic management of posterior cervical spinal fusion utilizing block of the frontal nerve, the greater occipital nerve, and the superficial cervical plexus in a patient with athetoid cerebral palsy. A 69-year-old woman (height 157 cm; weight 33 kg) with athetoid cerebral palsy was scheduled to undergo posterior cervical spinal fusion for cervical spondylotic myelopathy. After induction of general anesthesia, we performed tracheal intubation using the Pentax-AWS Airwayscope with a thin Intlock. After tracheal intubation, we used ropivacaine for the frontal nerve, greater occipital nerve, and superficial cervical plexus block. Anesthetic maintenance was performed with total intravenous anesthesia utilizing propofol and remifentanil. Continuous administration of dexmedetomidine was started during operation. Following surgery, smooth spontaneous ventilation was observed following uneventful extubation. No significant pain and no athetoid movement were observed under continuous administration of dexmedetomidine. PMID:26422967

  2. Occipital Condyle Fracture with Accompanying Meningeal Spinal Cysts as a result of Cervical Spine Injury in 15-Year-Old Girl

    PubMed Central

    Wiktor, ?ukasz; Tomaszewski, Ryszard

    2015-01-01

    The occipital condyle fracture is rare injury of the craniocervical junction. Meningeal spinal cysts are rare tumors of the spinal cord. Depending on location, these lesions may be classified as extradural and subdural, but extradural spinal cysts are more common. We present the case of a 15-year-old girl who suffered from avulsion occipital condyle fracture treated with use of “halo-vest” system. We established that clinical effect after completed treatment is very good. Control MRI evaluation was performed 12 months after removal of “halo-vest” traction, and clinically silent extradural meningeal spinal cysts were detected at the ventral side of the spinal cord in the cervical segment of the spine. Due to clinically silent course of the disease, we decided to use the conservative treatment. The patient remains under control of our department. PMID:26543656

  3. 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.

  4. Combined bi-occipital suboccipital transsinus transtentorial approach for resection of a pineal region falcotentorial meningioma: operative video and technical nuances.

    PubMed

    Liu, James K

    2016-01-01

    Large deep-seated meningiomas of the falcotentorial region present a formidable surgical challenge. In this operative video, the author demonstrates the combined bi-occipital suboccipital transsinus transtentorial approach for microsurgical resection of a large falcotentorial meningioma. This approach involves division of the less dominant transverse sinus after assessment of the venous pressure before and after clipping of the sinus with continuous neurophysiologic monitoring. Mild retraction of the occipital lobe and cerebellum results in a wide supra- and infratentorial exposure of extensive pineal region tumors. This video atlas demonstrates the operative technique and surgical nuances, including patient positioning, supra- and infratentorial craniotomy, transsinus transtentorial incision, and tumor removal with preservation of the vein of Galen complex. In summary, the combined bi-occipital suboccipital transsinus transtentorial approach provides a wide supra- and infratentorial surgical corridor for removal of select falcotentorial meningiomas. The video can be found here: https://youtu.be/3aD8h2uwBAo . PMID:26722686

  5. Intracranial spectral amplitude dynamics of perceptual suppression in fronto-insular, occipito-temporal, and primary visual cortex

    PubMed Central

    Vidal, Juan R.; Perrone-Bertolotti, Marcela; Kahane, Philippe; Lachaux, Jean-Philippe

    2015-01-01

    If conscious perception requires global information integration across active distant brain networks, how does the loss of conscious perception affect neural processing in these distant networks? Pioneering studies on perceptual suppression (PS) described specific local neural network responses in primary visual cortex, thalamus and lateral prefrontal cortex of the macaque brain. Yet the neural effects of PS have rarely been studied with intracerebral recordings outside these cortices and simultaneously across distant brain areas. Here, we combined (1) a novel experimental paradigm in which we produced a similar perceptual disappearance and also re-appearance by using visual adaptation with transient contrast changes, with (2) electrophysiological observations from human intracranial electrodes sampling wide brain areas. We focused on broadband high-frequency (50–150 Hz, i.e., gamma) and low-frequency (8–24 Hz) neural activity amplitude modulations related to target visibility and invisibility. We report that low-frequency amplitude modulations reflected stimulus visibility in a larger ensemble of recording sites as compared to broadband gamma responses, across distinct brain regions including occipital, temporal and frontal cortices. Moreover, the dynamics of the broadband gamma response distinguished stimulus visibility from stimulus invisibility earlier in anterior insula and inferior frontal gyrus than in temporal regions, suggesting a possible role of fronto-insular cortices in top–down processing for conscious perception. Finally, we report that in primary visual cortex only low-frequency amplitude modulations correlated directly with perceptual status. Interestingly, in this sensory area broadband gamma was not modulated during PS but became positively modulated after 300 ms when stimuli were rendered visible again, suggesting that local networks could be ignited by top–down influences during conscious perception. PMID:25642199

  6. Inferior-frontal cortex phase synchronizes with the temporal-parietal junction prior to successful change detection.

    PubMed

    Micheli, Cristiano; Kaping, Daniel; Westendorff, Stephanie; Valiante, Taufik A; Womelsdorf, Thilo

    2015-10-01

    The inferior frontal gyrus (IFG) and the temporo-parietal junction (TPJ) are believed to be core structures of human brain networks that activate when sensory top-down expectancies guide goal directed behavior and attentive perception. But it is unclear how activity in IFG and TPJ coordinates during attention demanding tasks and whether functional interactions between both structures are related to successful attentional performance. Here, we tested these questions in electrocorticographic (ECoG) recordings in human subjects using a visual detection task that required sustained attentional expectancy in order to detect non-salient, near-threshold visual events. We found that during sustained attention the successful visual detection was predicted by increased phase synchronization of band-limited 15-30 Hz beta band activity that was absent prior to misses. Increased beta-band phase alignment during attentional engagement early during the task was restricted to inferior and lateral prefrontal cortex, but with sustained attention it extended to long-range IFG-TPJ phase synchronization and included superior prefrontal areas. In addition to beta, a widely distributed network of brain areas comprising the occipital cortex showed enhanced and reduced alpha band phase synchronization before correct detections. These findings identify long-range phase synchrony in the 15-30 Hz beta band as the mesoscale brain signal that predicts the successful deployment of attentional expectancy of sensory events. We speculate that localized beta coherent states in prefrontal cortex index 'top-down' sensory expectancy whose coupling with TPJ subregions facilitates the gating of relevant visual information. PMID:26119023

  7. Elastic instabilities in a layered cerebral cortex: A revised axonal tension model for cortex folding

    E-print Network

    O. V. Manyuhina; David Mayett; J. M. Schwarz

    2014-12-04

    We model the elasticity of the cerebral cortex as a layered material with bending energy along the layers and elastic energy between them in both planar and polar geometries. The cortex is also subjected to axons pulling from the underlying white matter. Above a critical threshold force, a "flat" cortex configuration becomes unstable and periodic unduluations emerge, i.e. a buckling instability occurs. These undulations may indeed initiate folds in the cortex. We identify analytically the critical force and the critical wavelength of the undulations. Both quantities are physiologically relevant values. Our model is a revised version of the axonal tension model for cortex folding, with our version taking into account the layered structure of the cortex. Moreover, our model draws a connection with another competing model for cortex folding, namely the differential growth-induced buckling model. For the polar geometry, we study the relationship between brain size and the critical force and wavelength to understand why small mice brains exhibit no folds, while larger human brains do, for example. Finally, an estimate of the bending rigidity constant for the cortex can be made based on the critical wavelength.

  8. 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

  9. Tuning of temporo-occipital activity by frontal oscillations during virtual mirror exposure causes erroneous self-recognition.

    PubMed

    Serino, Andrea; Sforza, Anna Laura; Kanayama, Noriaki; van Elk, Michiel; Kaliuzhna, Mariia; Herbelin, Bruno; Blanke, Olaf

    2015-10-01

    Self-face recognition, a hallmark of self-awareness, depends on 'off-line' stored information about one's face and 'on-line' multisensory-motor face-related cues. The brain mechanisms of how on-line sensory-motor processes affect off-line neural self-face representations are unknown. This study used 3D virtual reality to create a 'virtual mirror' in which participants saw an avatar's face moving synchronously with their own face movements. Electroencephalographic (EEG) analysis during virtual mirror exposure revealed mu oscillations in sensory-motor cortex signalling on-line congruency between the avatar's and participants' movements. After such exposure and compatible with a change in their off-line self-face representation, participants were more prone to recognize the avatar's face as their own, and this was also reflected in the activation of face-specific regions in the inferotemporal cortex. Further EEG analysis showed that the on-line sensory-motor effects during virtual mirror exposure caused these off-line visual effects, revealing the brain mechanisms that maintain a coherent self-representation, despite our continuously changing appearance. PMID:26215485

  10. Motor Cortex Neuroplasticity Following Brachial Plexus Transfer

    PubMed Central

    Dimou, Stefan; Biggs, Michael; Tonkin, Michael; Hickie, Ian B.; Lagopoulos, Jim

    2013-01-01

    In the past decade, research has demonstrated that cortical plasticity, once thought only to exist in the early stages of life, does indeed continue on into adulthood. Brain plasticity is now acknowledged as a core principle of brain function and describes the ability of the central nervous system to adapt and modify its structural organization and function as an adaptive response to functional demand. In this clinical case study we describe how we used neuroimaging techniques to observe the functional topographical expansion of a patch of cortex along the sensorimotor cortex of a 27-year-old woman following brachial plexus transfer surgery to re-innervate her left arm. We found bilateral activations present in the thalamus, caudate, insula as well as across the sensorimotor cortex during an elbow flex motor task. In contrast we found less activity in the sensorimotor cortex for a finger tap motor task in addition to activations lateralized to the left inferior frontal gyrus and thalamus and bilaterally for the insula. From a pain perspective the patient who had experienced extensive phantom limb pain (PLP) before surgery found these sensations were markedly reduced following transfer of the right brachial plexus to the intact left arm. Within the context of this clinical case the results suggest that functional improvements in limb mobility are associated with increased activation in the sensorimotor cortex as well as reduced PLP. PMID:23966938

  11. FIRST PROOF Occipital Lobe

    E-print Network

    Grill-Spector, Kalanit

    is approximately 12% of the total surface area of the neocortex of the brain. Direct electrical stimulation (retinotopy), which is inverted due to the optical properties of the cornea and lens of the eye. Information is crossed. Visual information from the left half of the visual field (from both the right and the left eyes

  12. The Age of Human Cerebral Cortex Neurons

    SciTech Connect

    Bhardwaj, R D; Curtis, M A; Spalding, K L; Buchholz, B A; Fink, D; Bjork-Eriksson, T; Nordborg, C; Gage, F H; Druid, H; Eriksson, P S; Frisen, J

    2006-04-06

    The traditional static view of the adult mammalian brain has been challenged by the realization of continuous generation of neurons from stem cells. Based mainly on studies in experimental animals, adult neurogenesis may contribute to recovery after brain insults and decreased neurogenesis has been implicated in the pathogenesis of neurological and psychiatric diseases in man. The extent of neurogenesis in the adult human brain has, however, been difficult to establish. We have taken advantage of the integration of {sup 14}C, generated by nuclear bomb tests during the Cold War, in DNA to establish the age of neurons in the major areas of the human cerebral cortex. Together with the analysis of the cortex from patients who received BrdU, which integrates in the DNA of dividing cells, our results demonstrate that whereas non-neuronal cells turn over, neurons in the human cerebral cortex are not generated postnatally at detectable levels, but are as old as the individual.

  13. Spatial updating in human parietal cortex

    NASA Technical Reports Server (NTRS)

    Merriam, Elisha P.; Genovese, Christopher R.; Colby, Carol L.

    2003-01-01

    Single neurons in monkey parietal cortex update visual information in conjunction with eye movements. This remapping of stimulus representations is thought to contribute to spatial constancy. We hypothesized that a similar process occurs in human parietal cortex and that we could visualize it with functional MRI. We scanned subjects during a task that involved remapping of visual signals across hemifields. We observed an initial response in the hemisphere contralateral to the visual stimulus, followed by a remapped response in the hemisphere ipsilateral to the stimulus. We ruled out the possibility that this remapped response resulted from either eye movements or visual stimuli alone. Our results demonstrate that updating of visual information occurs in human parietal cortex.

  14. The anterior cingulate cortex and pain processing

    PubMed Central

    Fuchs, Perry N.; Peng, Yuan Bo; Boyette-Davis, Jessica A.; Uhelski, Megan L.

    2014-01-01

    The neural network that contributes to the suffering which accompanies persistent pain states involves a number of brain regions. Of primary interest is the contribution of the cingulate cortex in processing the affective component of pain. The purpose of this review is to summarize recent data obtained using novel behavioral paradigms in animals based on measuring escape and/or avoidance of a noxious stimulus. These paradigms have successfully been used to study the nature of the neuroanatomical and neurochemical contributions of the anterior cingulate cortex (ACC) to higher order pain processing in rodents. PMID:24829554

  15. 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

  16. Keynote Address: Revaluing the Orbital Prefrontal Cortex

    PubMed Central

    DOLAN, R. J.

    2010-01-01

    The importance of orbitofrontal cortex (OFC) in human behavioral regulation is no longer a matter of dispute, though its precise role remains a matter of ongoing investigation. It is ironic that this revaluation of OFC required a major departure from a historical nadir, during which it was viewed as redundant or “silent cortex,” a situation that prevailed even up to the latter half of the 20th century. The increasing wealth of data from diverse fields within neuroscience now provides an unambiguous testament to the importance of this cortical region in behavioral regulation and cognition in general. PMID:17846153

  17. Global optimization of cerebral cortex layout Christopher Cherniak*

    E-print Network

    Cherniak, Christopher

    Global optimization of cerebral cortex layout Christopher Cherniak* , Zekeria Mokhtarzada*, Raul than the macroeconomic patterns, which may indicate cortex optimizing mechanisms involve more global optimality level. The optimization problem here, originating in microcircuit design, is: Given connections

  18. Stimulus similarity modulates competitive interactions in human visual cortex

    E-print Network

    Kastner, Sabine

    Stimulus similarity modulates competitive interactions in human visual cortex Department of Psychology and Center for the Study of Brain, Mind and Behavior, Princeton University, Princeton, NJ., & Kastner, S. (2007). Stimulus similarity modulates competitive interactions in human visual cortex. Journal

  19. Structure and plasticity potential of neural networks in the cerebral cortex

    NASA Astrophysics Data System (ADS)

    Fares, Tarec Edmond

    In this thesis, we first described a theoretical framework for the analysis of spine remodeling plasticity. We provided a quantitative description of two models of spine remodeling in which the presence of a bouton is either required or not for the formation of a new synapse. We derived expressions for the density of potential synapses in the neuropil, the connectivity fraction, which is the ratio of actual to potential synapses, and the number of structurally different circuits attainable with spine remodeling. We calculated these parameters in mouse occipital cortex, rat CA1, monkey V1, and human temporal cortex. We found that on average a dendritic spine can choose among 4-7 potential targets in rodents and 10-20 potential targets in primates. The neuropil's potential for structural circuit remodeling is highest in rat CA1 (7.1-8.6 bits/mum3) and lowest in monkey V1 (1.3-1.5 bits/mum 3 We next studied the role neuron morphology plays in defining synaptic connectivity. As previously stated it is clear that only pairs of neurons with closely positioned axonal and dendritic branches can be synaptically coupled. For excitatory neurons in the cerebral cortex, ). We also evaluated the lower bound of neuron selectivity in the choice of synaptic partners. Post-synaptic excitatory neurons in rodents make synaptic contacts with more than 21-30% of pre-synaptic axons encountered with new spine growth. Primate neurons appear to be more selective, making synaptic connections with more than 7-15% of encountered axons. We next studied the role neuron morphology plays in defining synaptic connectivity. As previously stated it is clear that only pairs of neurons with closely positioned axonal and dendritic branches can be synaptically coupled. For excitatory neurons in the cerebral cortex, such axo-dendritic oppositions, or potential synapses, must be bridged by dendritic spines to form synaptic connections. To explore the rules by which synaptic connections are formed within the constraints imposed by neuron morphology, we compared the distributions of the numbers of actual and potential synapses between pre- and post-synaptic neurons forming different laminar projections in rat barrel cortex. Quantitative comparison explicitly ruled out the hypothesis that individual synapses between neurons are formed independently of each other. Instead, the data are consistent with a cooperative scheme of synapse formation, where multiple-synaptic connections between neurons are stabilized, while neurons that do not establish a critical number of synapses are not likely to remain synaptically coupled. In the above two projects, analysis of potential synapse numbers played an important role in shaping our understanding of connectivity and structural plasticity. In the third part of this thesis, we shift our attention to the study of the distribution of potential synapse numbers. This distribution is dependent on the details of neuron morphology and it defines synaptic connectivity patterns attainable with spine remodeling. To better understand how the distribution of potential synapse numbers is influenced by the overlap and the shapes of axonal and dendritic arbors, we first analyzed uniform disconnected arbors generated in silico. The resulting distributions are well described by binomial functions. We used a dataset of neurons reconstructed in 3D and generated the potential synapse distributions for neurons of different classes. Quantitative analysis showed that the binomial distribution is a good fit to this data as well. All distributions considered clustered into two categories, inhibitory to inhibitory and excitatory to excitatory projections. We showed that the distributions of potential synapse numbers are universally described by a family of single parameter (p) binomial functions, where p = 0.08, and for the inhibitory and p = 0.19 for the excitatory projections. In the last part of this thesis an attempt is made to incorporate some of the biological constraints we considered thus far, into an artificial neural network model. It became

  20. 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

  1. 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)

  2. Pushing the Boundaries of Fine-Grained Object Classification with fMRI Decoding in Human Occipito-Temporal Cortex.

    PubMed

    Fannjiang, Clara; Iordan, Marius Catalin; Beck, Diane; Fei-Fei, Li

    2015-09-01

    Multi-voxel pattern analysis or 'decoding' has become a widespread tool for investigating how much object and scene category information is linearly readable from fMRI response patterns. Previous studies have compared the performance of various classifiers on this task (Laconte et al., 2005; Misaki et al., 2010; Yourganov et al., 2014), however, with the fundamental limitation that comparisons are made on simple, often binary classification problems. Arguably, as questions probed by fMRI experiments become more complex, they demand methods that can expose subtle distinctions between large sets of categories. To address this issue, we performed the first evaluation of multivariate classifiers on fine-grained object categorization. We tested several commonly used classifiers: correlation classifier (CC), linear support vector machine (SVM), and linear discriminant analysis (LDA). For the latter, we employed two regularization schemes: principal components (LDA-PC) and ridge regression (LDA-RR). We benchmarked these classifiers on three passive-viewing, block-design fMRI datasets comprising 16, 27, and 32 fine-grained object categories, respectively. To assess the classification tasks, we selected several regions of interest (ROI) across visual cortex: early visual areas (V1, V2, V3v, hV4), scene- (PPA, TOS, RSC), face- (FFA), and object-selective regions (LOC). We evaluated the classifiers on the following criteria: mean decoding accuracy, number of categories decoded significantly above chance, and robustness of decoding accuracy to ROI size. Our comparisons on these challenging fine-grained datasets showed that, while all classifiers could decode category above chance across multiple regions, LDA-RR consistently outperformed the others across most ROIs on both mean decoding accuracy and number of categories decoded above chance. We reached a peak classification accuracy of 16% on 32-way categorization in LOC. Thus, despite the current popularity of CC and SVM in fMRI studies, our results suggest that LDA-RR should be the tool of choice for experimental questions involving complex, fine-grained category distinctions. Meeting abstract presented at VSS 2015. PMID:26326855

  3. Mindfulness training modulates value signals in ventromedial prefrontal cortex through input from insular cortex

    E-print Network

    Buehrer, R. Michael

    Mindfulness training modulates value signals in ventromedial prefrontal cortex through input from Mindfulness training Longitudinal design Neuroimaging research has demonstrated that ventromedial prefrontal biological basis. It has been hypothesized that mindful- ness training (MT) provides one path for gaining

  4. The Frontal Cortex and Exogenous Attentional Orienting

    E-print Network

    Chatterjee, Anjan

    a reorienting deficit that extends in duration well beyond established boundaries of the normal reflexive to different parts of the dorsolateral prefrontal cortex. & INTRODUCTION The human visual system is constantly faced with enor- mous amounts of changing visual stimuli, much of which is irrelevant to behavioral

  5. 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…

  6. Visual Cortex! Vision Science Lectures in Ophthalmology

    E-print Network

    Mullen, Kathy T.

    in luminance Chaudhuri, Fig 9.14 #12;retina-LGN-cortex KSJ, Fig 27-4 #12;V1 neurons: orientation selectivity KSJ, Fig 27-11 #12;V1 neurons: direction selectivity #12 as stimulus filters! #12;near and far cells KSJ, Fig 28-14 #12;ocular dominance columns KSJ, Fig 27-16 #12

  7. 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

  8. Hierarchical error representation in medial prefrontal cortex.

    PubMed

    Zarr, Noah; Brown, Joshua W

    2016-01-01

    The medial prefrontal cortex (mPFC) is reliably activated by both performance and prediction errors. Error signals have typically been treated as a scalar, and it is unknown to what extent multiple error signals may co-exist within mPFC. Previous studies have shown that lateral frontal cortex (LFC) is arranged in a hierarchy of abstraction, such that more abstract concepts and rules are represented in more anterior cortical regions. Given the close interaction between lateral and medial prefrontal cortex, we explored the hypothesis that mPFC would be organized along a similar rostro-caudal gradient of abstraction, such that more abstract prediction errors are represented further anterior and more concrete errors further posterior. We show that multiple prediction error signals can be found in mPFC, and furthermore, these are arranged in a rostro-caudal gradient of abstraction which parallels that found in LFC. We used a task that requires a three-level hierarchy of rules to be followed, in which the rules changed without warning at each level of the hierarchy. Task feedback indicated which level of the rule hierarchy changed and led to corresponding prediction error signals in mPFC. Moreover, each identified region of mPFC was preferentially functionally connected to correspondingly anterior regions of LFC. These results suggest the presence of a parallel structure between lateral and medial prefrontal cortex, with the medial regions monitoring and evaluating performance based on rules maintained in the corresponding lateral regions. PMID:26343320

  9. The Piriform Cortex and Human Focal Epilepsy

    PubMed Central

    Vaughan, David N.; Jackson, Graeme D.

    2014-01-01

    It is surprising that the piriform cortex, when compared to the hippocampus, has been given relatively little significance in human epilepsy. Like the hippocampus, it has a phylogenetically preserved three-layered cortex that is vulnerable to excitotoxic injury, has broad connections to both limbic and cortical areas, and is highly epileptogenic – being critical to the kindling process. The well-known phenomenon of early olfactory auras in temporal lobe epilepsy highlights its clinical relevance in human beings. Perhaps because it is anatomically indistinct and difficult to approach surgically, as it clasps the middle cerebral artery, it has, until now, been understandably neglected. In this review, we emphasize how its unique anatomical and functional properties, as primary olfactory cortex, predispose it to involvement in focal epilepsy. From recent convergent findings in human neuroimaging, clinical epileptology, and experimental animal models, we make the case that the piriform cortex is likely to play a facilitating and amplifying role in human focal epileptogenesis, and may influence progression to epileptic intractability. PMID:25538678

  10. Developmental Outcomes after Early Prefrontal Cortex Damage

    ERIC Educational Resources Information Center

    Eslinger, Paul J.; Flaherty-Craig, Claire V.; Benton, Arthur L.

    2004-01-01

    The neuropsychological bases of cognitive, social, and moral development are minimally understood, with a seemingly wide chasm between developmental theories and brain maturation models. As one approach to bridging ideas in these areas, we review 10 cases of early prefrontal cortex damage from the clinical literature, highlighting overall clinical…

  11. 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…

  12. Flood risk analysis and adaptive strategy in context of uncertainties: a case study of Nhieu Loc Thi Nghe Basin, Ho Chi Minh City

    NASA Astrophysics Data System (ADS)

    Ho, Long-Phi; Chau, Nguyen-Xuan-Quang; Nguyen, Hong-Quan

    2013-04-01

    The Nhieu Loc - Thi Nghe basin is the most important administrative and business area of Ho Chi Minh City. Due to system complexity of the basin such as the increasing trend of rainfall intensity, (tidal) water level and land subsidence, the simulation of hydrological, hydraulic variables for flooding prediction seems rather not adequate in practical projects. The basin is still highly vulnerable despite of multi-million USD investment for urban drainage improvement projects since the last decade. In this paper, an integrated system analysis in both spatial and temporal aspects based on statistical, GIS and modelling approaches has been conducted in order to: (1) Analyse risks before and after projects, (2) Foresee water-related risk under uncertainties of unfavourable driving factors and (3) Develop a sustainable flood risk management strategy for the basin. The results show that given the framework of risk analysis and adaptive strategy, certain urban developing plans in the basin must be carefully revised and/or checked in order to reduce the highly unexpected loss in the future

  13. Cholecystokinin from the entorhinal cortex enables neural plasticity in the auditory cortex.

    PubMed

    Li, Xiao; Yu, Kai; Zhang, Zicong; Sun, Wenjian; Yang, Zhou; Feng, Jingyu; Chen, Xi; Liu, Chun-Hua; Wang, Haitao; Guo, Yi Ping; He, Jufang

    2014-03-01

    Patients with damage to the medial temporal lobe show deficits in forming new declarative memories but can still recall older memories, suggesting that the medial temporal lobe is necessary for encoding memories in the neocortex. Here, we found that cortical projection neurons in the perirhinal and entorhinal cortices were mostly immunopositive for cholecystokinin (CCK). Local infusion of CCK in the auditory cortex of anesthetized rats induced plastic changes that enabled cortical neurons to potentiate their responses or to start responding to an auditory stimulus that was paired with a tone that robustly triggered action potentials. CCK infusion also enabled auditory neurons to start responding to a light stimulus that was paired with a noise burst. In vivo intracellular recordings in the auditory cortex showed that synaptic strength was potentiated after two pairings of presynaptic and postsynaptic activity in the presence of CCK. Infusion of a CCKB antagonist in the auditory cortex prevented the formation of a visuo-auditory association in awake rats. Finally, activation of the entorhinal cortex potentiated neuronal responses in the auditory cortex, which was suppressed by infusion of a CCKB antagonist. Together, these findings suggest that the medial temporal lobe influences neocortical plasticity via CCK-positive cortical projection neurons in the entorhinal cortex. PMID:24343575

  14. FMRI analysis of contrast polarity processing in face-selective cortex in humans and monkeys

    PubMed Central

    Yue, Xiaomin; Nasr, Shahin; Devaney, Kathryn J.; Holt, Daphne J.; Tootell, Roger B.H.

    2013-01-01

    Recognition is strongly impaired when the normal contrast polarity of faces is reversed. For instance, otherwise-familiar faces become very difficult to recognize when viewed as photographic negatives. Here, we used fMRI to demonstrate related properties in visual cortex: 1) fMRI responses in the human Fusiform Face Area (FFA) decreased strongly (26%) to contrast-reversed faces across a wide range of contrast levels (5.3-100% RMS contrast), in all subjects tested. In a whole brain analysis, this contrast polarity bias was largely confined to the Fusiform Face Area (FFA; p < 0.0001), with possible involvement of a left occipital face-selective region. 2) It is known that reversing facial contrast affects three image properties in parallel (absorbance, shading, and specular reflection). Here, comparison of FFA responses to those in V1 suggests that the contrast polarity bias is produced in FFA only when all three component properties were reversed simultaneously, which suggests a prominent non-linearity in FFA processing. 3) Across a wide range (180°) of illumination source angles, 3D face shapes without texture produced response constancy in FFA, without a contrast polarity bias. 4) Consistent with psychophysics, analogous fMRI biases for normal contrast polarity were not produced by non-face objects, with image statistics similar to the face stimuli. 5) Using fMRI, we also demonstrated a contrast polarity bias in awake behaving macaque monkeys, in the cortical region considered homologous to human FFA. Thus common cortical mechanisms may underlie facial contrast processing across ~ 25 million years of primate evolution. PMID:23518007

  15. Reduced Haemodynamic Response in the Ageing Visual Cortex Measured by Absolute fNIRS.

    PubMed

    Ward, Laura McKernan; Aitchison, Ross Thomas; Tawse, Melisa; Simmers, Anita Jane; Shahani, Uma

    2015-01-01

    The effect of healthy ageing on visual cortical activation is still to be fully explored. This study aimed to elucidate whether the haemodynamic response (HDR) of the visual cortex altered as a result of ageing. Visually normal (healthy) participants were presented with a simple visual stimulus (reversing checkerboard). Full optometric screening was implemented to identify two age groups: younger adults (n = 12, mean age 21) and older adults (n = 13, mean age 71). Frequency-domain Multi-distance (FD-MD) functional Near-Infrared Spectroscopy (fNIRS) was used to measure absolute changes in oxygenated [HbO] and deoxygenated [HbR] haemoglobin concentrations in the occipital cortices. Utilising a slow event-related design, subjects viewed a full field reversing checkerboard with contrast and check size manipulations (15 and 30 minutes of arc, 50% and 100% contrast). Both groups showed the characteristic response of increased [HbO] and decreased [HbR] during stimulus presentation. However, older adults produced a more varied HDR and often had comparable levels of [HbO] and [HbR] during both stimulus presentation and baseline resting state. Younger adults had significantly greater concentrations of both [HbO] and [HbR] in every investigation regardless of the type of stimulus displayed (p<0.05). The average variance associated with this age-related effect for [HbO] was 88% and [HbR] 91%. Passive viewing of a visual stimulus, without any cognitive input, showed a marked age-related decline in the cortical HDR. Moreover, regardless of stimulus parameters such as check size, the HDR was characterised by age. In concurrence with present neuroimaging literature, we conclude that the visual HDR decreases as healthy ageing proceeds. PMID:25909849

  16. 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

  17. Functional connectivity of the cortex of term and preterm infants and infants with Down's syndrome.

    PubMed

    Imai, Makiko; Watanabe, Hama; Yasui, Kojiro; Kimura, Yuki; Shitara, Yoshihiko; Tsuchida, Shinya; Takahashi, Naoto; Taga, Gentaro

    2014-01-15

    Near-infrared spectroscopy (NIRS) imaging studies have revealed the functional development of the human brain in early infancy. By measuring spontaneous fluctuations in cerebral blood oxygenation with NIRS, we can examine the developmental status of the functional connectivity of networks in the cortex. However, it has not been clarified whether premature delivery and/or chromosomal abnormalities affect the development of the functional connectivity of the cortex. In the current study, we investigated the spontaneous brain activity of sleeping infants who were admitted to a neonatal intensive care unit at term age. We classified them into the 3 following infant groups: (i) term-or-late-preterm, (ii) early-preterm, and (iii) Down's syndrome (DS). We used multichannel NIRS to measure the spontaneous changes in oxygenated hemoglobin (oxy-Hb) and deoxygenated hemoglobin (deoxy-Hb) at 10 measurement channels, which covered the frontal, temporal, and occipital regions. In order to reveal the functional connectivity of the cortical networks, we calculated the temporal correlations of the time-course signals among all of the pairs of measurement channels. The functional connectivity was classified into the 4 following types: (i) short-range, (ii) contralateral-transverse, (iii) ipsilateral-longitudinal, and (iv) control. In order to examine whether the local properties of hemodynamics reflected any pathological conditions, we calculated the phase differences between the oxy- and deoxy-Hb time-course signals in the 3 groups. The statistical analyses of the functional connectivity data showed main effects of group and the types of connectivity. For the group effect, the mean functional connectivity of the infants in the term-or-late-preterm group did not differ from that in the early-preterm group, and the mean functional connectivity of the infants in the DS group was lower than that in the other 2 groups. For the effect of types of connectivity, short-range connectivity was highest compared to any of the other types of connectivity, and the second highest connectivity was the contralateral-transverse one. The phase differences between the oxy- and deoxy-Hb changes showed that there were significant differences between the DS group and the other 2 groups. Our findings suggested that the development of the functional connectivity of cortical networks did not differ between term-or-late-preterm infants and early-preterm infants around term-equivalent ages, while DS infants had alterations in their functional connectivity development and local hemodynamics at term age. The highest short-range connectivity and the second highest contralateral-transverse connectivity suggested that the precursors for the basic cortical networks of functional connectivity were present at term age. PMID:23631984

  18. How do barrels form in somatosensory cortex?

    PubMed Central

    Li, Hong; Crair, Michael C.

    2011-01-01

    The somatosensory cortex of many rodents, lagomorphs, and marsupials contain distinct cytoarchitectonic features named “barrels” that reflect the pattern of large facial whiskers on the snout. Barrels are composed of clustered thalamocortical afferents relaying sensory information from one whisker surrounded by cell dense walls or “barrels” in layer 4 of the cortex. In many ways, barrels are a simple and relatively accessible canonical cortical column, making them a common model system for the examination of cortical development and function. Despite their experimental accessibility and popularity, we still lack a basic understanding of how and why barrels form in the first place. In this review, we will examine what is known about mechanisms of barrel development, focusing specifically on the recent literature utilizing the molecular–genetic power of mice as a model system for examining brain development. PMID:21534999

  19. Monkey cortex through fMRI glasses

    PubMed Central

    Vanduffel, Wim; Zhu, Qi; Orban, Guy A.

    2015-01-01

    In 1998 several groups reported the feasibility of functional magnetic resonance imaging (fMRI) experiments in monkeys, with the goal to bridge the gap between invasive nonhuman primate studies and human functional imaging. These studies yielded critical insights in the neuronal underpinnings of the BOLD signal. Furthermore, the technology has been successful in guiding electrophysiological recordings and identifying focal perturbation targets. Finally, invaluable information was obtained concerning human brain evolution. We here provide a comprehensive overview of awake monkey fMRI studies mainly confined to the visual system. We review the latest insights about the topographic organization of monkey visual cortex and discuss the spatial relationships between retinotopy and category and feature selective clusters. We briefly discuss the functional layout of parietal and frontal cortex and continue with a summary of some fascinating functional and effective connectivity studies. Finally, we review recent comparative fMRI experiments and speculate about the future of nonhuman primate imaging. PMID:25102559

  20. Anterior Insular Cortex and Emotional Awareness

    PubMed Central

    Gu, Xiaosi; Hof, Patrick R.; Friston, Karl J.; Fan, Jin

    2014-01-01

    This paper reviews the foundation for a role of the human anterior insular cortex (AIC) in emotional awareness, defined as the conscious experience of emotions. We first introduce the neuroanatomical features of AIC and existing findings on emotional awareness. Using empathy, the awareness and understanding of other people’s emotional states, as a test case, we then present evidence to demonstrate: 1) AIC and anterior cingulate cortex (ACC) are commonly coactivated as revealed by a meta-analysis, 2) AIC is functionally dissociable from ACC, 3) AIC integrates stimulus-driven and top-down information, and 4) AIC is necessary for emotional awareness. We propose a model in which AIC serves two major functions: integrating bottom-up interoceptive signals with top-down predictions to generate a current awareness state and providing descending predictions to visceral systems that provide a point of reference for autonomic reflexes. We argue that AIC is critical and necessary for emotional awareness. PMID:23749500

  1. Chemical and biological differentiation of Cortex Phellodendri Chinensis and Cortex Phellodendri Amurensis.

    PubMed

    Chen, Meng-Li; Xian, Yan-Fang; Ip, Siu-Po; Tsai, Sam-Hip; Yang, Ji-Yong; Che, Chun-Tao

    2010-10-01

    The Chinese herbal drug Cortex Phellodendri is derived from two species of PHELLODENDRON, P. CHINENSIS Schneid. and P. AMURENSE Rupr. Traditionally, Cortex Phellodendri Chinensis (CPC) and Cortex Phellodendri Amurensis (CPA) are used interchangeably because they are believed to share the same clinical efficacy. Berberine has been believed to be the active ingredient of the herbs. However, recent studies have shown that the content of berberine is much higher in CPC than in CPA. Interestingly, the majority of researches deal with CPA, the one with lower content of berberine. These observations provoke us to reconsider the active ingredients of Cortex Phellodendri. In this study, two traditional usages (antidiarrheal and antibacterial) of Cortex Phellodendri were compared with the chemical analysis of the two herb species used in its formulation. The results suggest that berberine is one of the active ingredients responsible for the antidiarrheal and antibacterial activities of the herbs, but that other chemical ingredients are also involved in regulating the biological actions of the herbal drug. These chemical ingredients may have the same or the opposite effect as berberine. The effectiveness of the herbs is more likely to correlate to the content of total alkaloids rather than to the content of berberine. PMID:20354951

  2. Amodal processing in human prefrontal cortex.

    PubMed

    Tamber-Rosenau, Benjamin J; Dux, Paul E; Tombu, Michael N; Asplund, Christopher L; Marois, René

    2013-07-10

    Information enters the cortex via modality-specific sensory regions, whereas actions are produced by modality-specific motor regions. Intervening central stages of information processing map sensation to behavior. Humans perform this central processing in a flexible, abstract manner such that sensory information in any modality can lead to response via any motor system. Cognitive theories account for such flexible behavior by positing amodal central information processing (e.g., "central executive," Baddeley and Hitch, 1974; "supervisory attentional system," Norman and Shallice, 1986; "response selection bottleneck," Pashler, 1994). However, the extent to which brain regions embodying central mechanisms of information processing are amodal remains unclear. Here we apply multivariate pattern analysis to functional magnetic resonance imaging (fMRI) data to compare response selection, a cognitive process widely believed to recruit an amodal central resource across sensory and motor modalities. We show that most frontal and parietal cortical areas known to activate across a wide variety of tasks code modality, casting doubt on the notion that these regions embody a central processor devoid of modality representation. Importantly, regions of anterior insula and dorsolateral prefrontal cortex consistently failed to code modality across four experiments. However, these areas code at least one other task dimension, process (instantiated as response selection vs response execution), ensuring that failure to find coding of modality is not driven by insensitivity of multivariate pattern analysis in these regions. We conclude that abstract encoding of information modality is primarily a property of subregions of the prefrontal cortex. PMID:23843526

  3. Evolution of a form of pure alexia without agraphia in a child sustaining occipital lobe infarction at 2 1/2 years.

    PubMed

    O'Hare, A E; Dutton, G N; Green, D; Coull, R

    1998-06-01

    The progress of cognitive visual dysfunction over an 8-year period of a child who sustained bilateral occipital-lobe infarctions at the age of 2 1/2 years is described. She survived with normal intelligence and went on to attend mainstream school. She manifested many features of cognitive visual impairment and, in particular, developed a form of pure alexia without agraphia. She achieved some letter-by-letter reading but no sight vocabulary development, including to her own name. She learned to write imaginatively employing phonetically true spelling but cannot read what she has written. Her progress and the difficulties encountered during the management of her condition are discussed in this first case report of the evolution of pure alexia without agraphia in childhood. The features of this syndrome in the developing child who has never developed the capacity to read are contrasted with that seen in affected adults. PMID:9652784

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

    PubMed Central

    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

  5. Chiari I malformation associated with atlanto-occipital assimilation presenting as orthopnea and cough syncope: a case report and review of literature.

    PubMed

    Mangubat, Erwin Zeta; Wilson, Tom; Mitchell, Brian A; Byrne, Richard W

    2014-08-01

    Although it is not uncommon for patients with Chiari I malformations to present with respiratory complaints, cough syncope is a rare presenting symptom. We report an adult patient who harbored both a Chiari I malformation and atlanto-occipital assimilation who complained of cough syncope, orthopnea, and central sleep apnea. The patient underwent decompressive craniectomy of the posterior fossa and cervical level 2 laminectomy. However, due to a possible initial underappreciation of the profound narrowing of the foramen magnum as a result of these concomitant pathologies, the patient may have had continued impaired cerebrospinal fluid flow, leading to a symptomatic pseudomeningocele and requiring a more extensive decompression that included a cervical level 3 laminectomy as well as a temporary lumbar drain. On 2-year follow-up, he has remained asymptomatic. PMID:25083365

  6. 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 ...

  7. Activity in prelimbic cortex subserves fear memory reconsolidation over time

    PubMed Central

    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 GABAA agonist muscimol (4.0 nmol in 0.2 ?L per hemisphere) was able to equally disrupt 1-, 7-, and 21-d-old contextual fear memories after their brief retrieval in rats. In all cases, this effect was prevented when memory reactivation was omitted. These results indicate that recent and remote fear memories are susceptible to reconsolidation blockade induced by prelimbic cortex inactivation. It was also demonstrated that the disrupting effect of prelimbic cortex inactivation on fear memory persisted over 11 d, and did not show extinction-related features, such as reinstatement. Infusing the same dose and volume of muscimol bilaterally into the infralimbic cortex after brief retrieval/reactivation of the fear memory did not disrupt it, as seen in prelimbic cortex-inactivated animals. The expression of Zif268/Egr1, the product of an immediate early gene related to memory reconsolidation, was also less pronounced in the infralimbic cortex than in prelimbic cortex following memory retrieval/reactivation. Altogether, the present findings highlight that activity in the prelimbic cortex may reestablish reactivated aversive memories and, therefore, contribute to their maintenance over time. PMID:24344180

  8. 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

  9. Parametric responses to rotation symmetry in mid-level visual cortex.

    PubMed

    Kohler, Peter; Yakovleva, Alexandra; Clarke, Alasdair; Liu, Yanxi; Norcia, Anthony

    2015-09-01

    Symmetry is a fundamental principle of perceptual organization that contributes to multiple aspects of vision, running the gamut from judgments of aesthetics and mate selection, to shape processing and surface orientation. Crystallographic group theory categorizes all possible two-dimensional repetitive patterns into 17 wallpaper groups, as unique combinations of the four fundamental symmetries: mirror reflection, translation, rotation and glide reflection (Liu et al., 2010). We have developed an algorithm that can generate a near-infinite number of well-controlled exemplars belonging to each of the 17 wallpaper groups. Here, we focus on four wallpaper groups that all contain rotation symmetry exclusively - only differing in the maximum order of rotation symmetry found in each group. We use an fMRI block design that isolates the symmetry-specific BOLD response by alternating group exemplar images with matched control images. Using scalp EEG, we have previously shown that the neural responses to the groups increase linearly with maximum order of rotation symmetry (Kohler et al., VSS 2014), indicating that rotation is represented parametrically. Our fMRI experiment (n=12) localizes this parametric effect in several extra-striate areas of human visual cortex (V4, VO1, LOC), while other visual areas have little response to rotation symmetry (e.g. MT). Interestingly, the parametric response is also seen in V3, an area that has previously been found to have little or no response to mirror symmetry (Sasaki et al 2005). The fact that V1 and V2 do not show the effect suggests a functional distinction between V3 and earlier visual areas. Neurons in intermediate-level visual areas like V4 have complex and diverse response properties (Roe et al., 2012) that are difficult to characterize systematically (Gallant et al., 1996). These results present a novel, well-defined stimulus set, the wallpaper groups, that can drive V4 and other mid-level visual areas in a robust and systematic way. Meeting abstract presented at VSS 2015. PMID:26326810

  10. Determining physical properties of the cell cortex

    E-print Network

    A. Saha; M. Nishikawa; M. Behrndt; C. -P. Heisenberg; F. Jülicher; S. W. Grill

    2015-07-02

    Actin and myosin assemble into a thin layer of a highly dynamic network underneath the membrane of eukaryotic cells. This network generates the forces that drive cell and tissue-scale morphogenetic processes. The effective material properties of this active network determine large-scale deformations and other morphogenetic events. For example,the characteristic time of stress relaxation (the Maxwell time)in the actomyosin sets the time scale of large-scale deformation of the cortex. Similarly, the characteristic length of stress propagation (the hydrodynamic length) sets the length scale of slow deformations, and a large hydrodynamic length is a prerequisite for long-ranged cortical flows. Here we introduce a method to determine physical parameters of the actomyosin cortical layer (in vivo). For this we investigate the relaxation dynamics of the cortex in response to laser ablation in the one-cell-stage {\\it C. elegans} embryo and in the gastrulating zebrafish embryo. These responses can be interpreted using a coarse grained physical description of the cortex in terms of a two dimensional thin film of an active viscoelastic gel. To determine the Maxwell time, the hydrodynamic length and the ratio of active stress and per-area friction, we evaluated the response to laser ablation in two different ways: by quantifying flow and density fields as a function of space and time, and by determining the time evolution of the shape of the ablated region. Importantly, both methods provide best fit physical parameters that are in close agreement with each other and that are similar to previous estimates in the two systems. We provide an accurate and robust means for measuring physical parameters of the actomyosin cortical layer.It can be useful for investigations of actomyosin mechanics at the cellular-scale, but also for providing insights in the active mechanics processes that govern tissue-scale morphogenesis.

  11. Parietal cortex: from sight to action.

    PubMed

    Rizzolatti, G; Fogassi, L; Gallese, V

    1997-08-01

    Recent findings have altered radically our thinking about the functional role of the parietal cortex. According to this view, the parietal lobe consists of a multiplicity of areas with specific connections to the frontal lobe. These areas, together with the frontal areas to which they are connected, mediate distinct sensorimotor transformations related to the control of hand, arm, eye or head movements. Space perception is not unitary, but derives from the joint activity of the fronto-parietal circuits that control actions requiring space computation. PMID:9287198

  12. Computational Modeling of Orientation Tuning Dynamics in Monkey Primary Visual Cortex

    E-print Network

    Pugh, Mary

    Computational Modeling of Orientation Tuning Dynamics in Monkey Primary Visual Cortex M. C. Pugh, D, monkey, primary visual cortex, lay- ers. 1 #12;Introduction How visual cells in the primary visual cortex

  13. Neuronal Correlates of Amblyopia in the Visual Cortex of Macaque Monkeys with Experimental Strabismus and Anisometropia

    E-print Network

    Kiper, Daniel C.

    Neuronal Correlates of Amblyopia in the Visual Cortex of Macaque Monkeys with Experimental. We studied the response properties of visual cortex neurons in six amblyopic macaques; three monkeys cortex; amblyopia; anisometropia; strabismus; macaque monkeys Visual function in adulthood depends

  14. Chemosensory convergence on primary olfactory cortex

    PubMed Central

    Maier, Joost X.; Wachowiak, Matt; Katz, Donald B.

    2012-01-01

    Food perception and preference formation relies on the ability to combine information from both the taste and olfactory systems. Accordingly, psychophysical investigations in humans and behavioral work in animals has shown that the taste system plays an integral role in odor processing. However, the neural basis for the influence of taste (gustation) on odor (olfaction) remains largely unknown. Here we tested the hypothesis that gustatory influence on olfactory processing occurs at the level of primary olfactory cortex. We recorded activity from single neurons in posterior olfactory (piriform) cortex (pPC) of awake rats while presenting basic taste solutions directly to the tongue. A significant portion of pPC neurons proved to respond selectively to taste stimuli. These taste responses were significantly reduced by blockade of the gustatory epithelium, were unaffected by blockade of the olfactory epithelium and were independent of respiration behavior. In contrast, responses to olfactory stimuli, recorded from the same area, were reduced by nasal epithelial deciliation and phase-locked to the respiration cycle. These results identify pPC as a likely site for gustatory influences on olfactory processing, which play an important role in food perception and preference formation. PMID:23197697

  15. Dynamic cortex stripping for vertebra evaluation

    NASA Astrophysics Data System (ADS)

    Stieger, James; Burns, Joseph E.; Yao, Jianhua; Summers, Ronald M.

    2015-03-01

    Vertebral cortex removal through cancellous bone reconstruction (CBR) algorithms on CT has been shown to enhance the detection rate of bone metastases by radiologists and reduce average reading time per case. Removal of the cortical bone provides an unobstructed view of the inside of vertebrae without any anomalous distractions. However, these algorithms rely on the assumption that the cortical bone of vertebrae can be removed without the identification of the endosteal cortical margin. We present a method for the identification of the endosteal cortical margin based on vertebral models and CT intensity information. First, triangular mesh models are created using the marching cubes algorithm. A search region is established along the normal of the surface and the image gradient is calculated at every point along the search region. The location with the greatest image gradient is selected as the corresponding point on the endosteal cortical margin. In order to analyze the strength of this method, ground truth and control models were also created. Our method was shown to have a significantly reduce the average error from 0.80 mm +/- 0.14 mm to 0.65 mm +/- 0.17 mm (p <0.0001) when compared to erosion. This method can potentially improve CBR algorithms, which improve visualization of cancellous bone lesions such as metastases, by more accurately identifying the inner wall of the vertebral cortex.

  16. Sound frequency representation in cat auditory cortex.

    PubMed

    Tsytsarev, Vassiliy; Yamazaki, Tadashi; Ribot, Jérôme; Tanaka, Shigeru

    2004-12-01

    Using the intrinsic signal optical recording technique, we reconstructed the two-dimensional pattern of stimulus-evoked neuronal activities in the auditory cortex of anesthetized and paralyzed cats. The average magnitude of intrinsic signal in response to a pure tone stimulus increased steadily as the sound pressure level increased. A detailed analysis demonstrated that the evoked signals at early frames were scaled by the sound pressure level, which in turn indicated the presence of a minimum level of sound pressure beyond which stimulus-related intrinsic signal can be generated. Intrinsic signals evoked significantly by pure tone stimuli of different frequencies were localized and arranged in an orderly manner in the middle ectosylvian gyrus, which indicates that the primary auditory field (AI) is tonotopically organized. The arrangement of optimal frequencies obtained from optical recordings of the same auditory cortex, which were conducted on different days, was highly reproducible. Furthermore, other auditory fields surrounding AI in the recorded area were allocated based on the observed tonotopicity. We also conducted unit recordings on the cats used for optical recording with the same set of acoustic stimuli. The gross feature of the arrangement of optimal frequencies determined by unit recordings agreed with the tonotopic arrangement determined by the optical recording, although the precise agreement was not obtained. PMID:15589090

  17. The medial prefrontal cortex in constructing personality models

    E-print Network

    Spreng, R. Nathan

    The medial prefrontal cortex in constructing personality models Jonathan B. Freeman and Ryan M A recent study by Hassabis et al. suggests that the brain constructs `personality models' of other people cortex (mPFC) contained information about the individual's unique combination of personality traits

  18. 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…

  19. Cerebral Cortex doi:10.1093/cercor/bhp162

    E-print Network

    Cortex and Pulvinar Nucleus of the Tree Shrew Ranida D. Chomsung1 , Haiyang Wei1 , Jonathan D. Day-Brown1 connections between the temporal cortex and the dorsal (Pd) and central (Pc) subdivisions of the tree shrew input from the superficial layers of the superior colliculus (SC). Tree shrews (Tupaia) are small, fast

  20. Insular Cortex Is Involved in Consolidation of Object Recognition Memory

    ERIC Educational Resources Information Center

    Bermudez-Rattoni, Federico; Okuda, Shoki; Roozendaal, Benno; McGaugh, James L.

    2005-01-01

    Extensive evidence indicates that the insular cortex (IC), also termed gustatory cortex, is critically involved in conditioned taste aversion and taste recognition memory. Although most studies of the involvement of the IC in memory have investigated taste, there is some evidence that the IC is involved in memory that is not based on taste. In…

  1. Circuit Dynamics and Coding Strategies in Rodent Somatosensory Cortex

    E-print Network

    Brumberg, Joshua

    Circuit Dynamics and Coding Strategies in Rodent Somatosensory Cortex DAVID J. PINTO,1,2 JOSHUA C., Joshua C. Brumberg, and Daniel J. Simons. Circuit dynamics and coding strategies in rodent somatosensory and thalamic barreloid neuron responses in rodent somatosensory cortex have indicated an active role for barrel

  2. Modeling Shape Representation in Visual Cortex Charles Fredrick Cadieu

    E-print Network

    Poggio, Tomaso

    Modeling Shape Representation in Visual Cortex Area V4 by Charles Fredrick Cadieu Submitted INSTITUTE OF TECHNOLOGY May 2005 Copyright 2005 Charles Fredrick Cadieu. All rights reserved. The author Representation in Visual Cortex Area V4 by Charles Fredrick Cadieu Submitted to the Department of Electrical

  3. 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

  4. 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…

  5. Cerebral Cortex doi:10.1093/cercor/bhs030

    E-print Network

    Sur, Mriganka

    Cerebral Cortex doi:10.1093/cercor/bhs030 Deletion of Ten-m3 Induces the Formation of Eye Dominance into ocular dominance columns in primary visual cortex (V1), whereas in rodents, this does not occur. Ten-m3 dominance domains. Segregation is confirmed by optical imaging of intrinsic signals. Single-unit recording

  6. Representation of Naturalistic Image Structure in the Primate Visual Cortex

    E-print Network

    Simoncelli, Eero

    cerebral cortex. We have probed the early stages of this cascade with "naturalistic" texture stimuli neural activity as it is trans- formed through a cascade of areas in the cerebral cortex. Neurons the past 50 years, the dominant view in both the computational and biological vision communities

  7. Receptive Fields and Maps in the Visual Cortex: Models of

    E-print Network

    Columbia University

    of ocular dominance columns in the cat or monkey primary visual cortex (reviewed in [44]). The cerebral1 Receptive Fields and Maps in the Visual Cortex: Models of Ocular Dominance and Orientation ``Models of Ocular Dominance and Orientation Columns.'' Reused by permission. ABSTRACT The formation

  8. 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,…

  9. Medial Prefrontal Cortex Lesions Abolish Contextual Control of Competing Responses

    ERIC Educational Resources Information Center

    Haddon, J. E.; Killcross, A. S.

    2005-01-01

    There is much debate as to the extent and nature of functional specialization within the different subregions of the prefrontal cortex. The current study was undertaken to investigate the effect of damage to medial prefrontal cortex subregions in the rat. Rats were trained on two biconditional discrimination tasks, one auditory and one visual, in…

  10. Discourse Production Following Injury to the Dorsolateral Prefrontal Cortex

    ERIC Educational Resources Information Center

    Coelho, Carl; Le, Karen; Mozeiko, Jennifer; Krueger, Frank; Grafman, Jordan

    2012-01-01

    Individuals with damage to the prefrontal cortex, and the dorsolateral prefrontal cortex (DLPFC) in particular, often demonstrate difficulties with the formulation of complex language not attributable to aphasia. The present study employed a discourse analysis procedure to characterize the language of individuals with left (L) or right (R) DLPFC…

  11. BEHAVIORAL NEUROSCIENCE Extinction reveals that primary sensory cortex predicts

    E-print Network

    Weinberger, Norman M.

    no longer predicts reinforcement. Rats (n = 11) were trained to bar-press to a signal tone (5.0 kBEHAVIORAL NEUROSCIENCE Extinction reveals that primary sensory cortex predicts reinforcement cortex, instrumental conditioning, learning-induced plasticity, memory strength, rat Abstract Primary

  12. Cerebral Cortex doi:10.1093/cercor/bhp206

    E-print Network

    : cognitive control, mixed blocked/event-related fMRI, parietal cortex, prefrontal cortex, task set in terms of mixing costs that index sustained changes during task-switching block (De Jong 2001; Reimers during task switching. A mixed blocked/event-related functional magnetic resonance imaging design enabled

  13. Representation of Cochlea Within Primav Auditory Cortex in the Cat

    E-print Network

    Kilgard, Michael P.

    Representation of Cochlea Within Primav Auditory Cortex in the Cat MICHAEL M. MERZENPCH, PAUL L of the cochlear basilar par- tition in the auditory region of the cerebral cortex of the cat. Their classic evoked patches in the dog (54-56) and cat (26) substanti- ated these conclusions. The former studies more

  14. The scaling of frontal cortex in primates and carnivores

    E-print Network

    Allman, John M.

    The scaling of frontal cortex in primates and carnivores Eliot C. Bush* and John M. Allman Biology primates and 15 carnivores. We find evidence for significant differences in scaling between pri- mates and carnivores. Primate frontal cortex hyperscales relative to the rest of neocortex and the rest of the brain

  15. Topographic maps in human frontal and parietal cortex

    E-print Network

    Whitney, David

    Topographic maps in human frontal and parietal cortex Michael A. Silver1 and Sabine Kastner2 1 of Brain, Mind, and Behavior, and Princeton Neuroscience Institute, Princeton University, Princeton, NJ resulted in the identification of many areas in human visual cortex and a description of the organization

  16. Reduced Anterior Cingulate Cortex Glutamatergic Concentrations in Childhood Major Depression

    ERIC Educational Resources Information Center

    Mirza, Yousha; Tang, Jennifer; Russell, Aileen; Banerjee, S. Preeya; Bhandari, Rashmi; Ivey, Jennifer; Rose, Michelle; Moore, Gregory J.; Rosenberg, David R.

    2004-01-01

    Objective: To examine in vivo glutamatergic neurochemical alterations in the anterior cingulate cortex of children with major depressive disorder (MDD). Method: Single-voxel proton magnetic resonance spectroscopic ([.sup.1]H-MRS) examinations of the anterior cingulate cortex were conducted in 13 psychotropic-naive children and adolescents with MDD…

  17. Learning in mammalian sensory cortex Geoffrey M Ghose

    E-print Network

    Ghose, Geoff

    with training can offer important insight into the physiological basis of learning in the cerebral cortex on cortical processing can improve with training. Thus, sensory areas of the cortex offer unique opportu- nities for the exploration of the physiological basis of learning. An understanding of the neural basis

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

    PubMed

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

    2014-06-01

    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. The discovery of motor cortex and its background.

    PubMed

    Gross, Charles G

    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, and d) localization of function in different regions of the cerebral cortex. This paper discusses their experiment and some developments in the previous two centuries that led to it including the ideas of Thomas Willis and Emanuel Swedenborg, the widespread interest in electricity and the localizations of function of Franz Joseph Gall, John Hughlings Jackson, and Paul Broca. We also consider the subsequent study of the motor cortex by David Ferrier and others. PMID:17620195

  20. 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

  1. 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

  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. What the orbitofrontal cortex does not do.

    PubMed

    Stalnaker, Thomas A; Cooch, Nisha K; Schoenbaum, Geoffrey

    2015-05-01

    The number of papers about the orbitofrontal cortex (OFC) has grown from 1 per month in 1987 to a current rate of over 50 per month. This publication stream has implicated the OFC in nearly every function known to cognitive neuroscience and in most neuropsychiatric diseases. However, new ideas about OFC function are typically based on limited data sets and often ignore or minimize competing ideas or contradictory findings. Yet true progress in our understanding of an area's function comes as much from invalidating existing ideas as proposing new ones. Here we consider the proposed roles for OFC, critically examining the level of support for these claims and highlighting the data that call them into question. PMID:25919962

  4. Co-release of noradrenaline and dopamine in the cerebral cortex elicited by single train and repeated train stimulation of the locus coeruleus

    PubMed Central

    Devoto, Paola; Flore, Giovanna; Saba, Pierluigi; Fà, Mauro; Gessa, Gian Luigi

    2005-01-01

    Background Previous studies by our group suggest that extracellular dopamine (DA) and noradrenaline (NA) may be co-released from noradrenergic nerve terminals in the cerebral cortex. We recently demonstrated that the concomitant release of DA and NA could be elicited in the cerebral cortex by electrical stimulation of the locus coeruleus (LC). This study analyses the effect of both single train and repeated electrical stimulation of LC on NA and DA release in the medial prefrontal cortex (mPFC), occipital cortex (Occ), and caudate nucleus. To rule out possible stressful effects of electrical stimulation, experiments were performed on chloral hydrate anaesthetised rats. Results Twenty min electrical stimulation of the LC, with burst type pattern of pulses, increased NA and DA both in the mPFC and in the Occ. NA in both cortices and DA in the mPFC returned to baseline within 20 min after the end of the stimulation period, while DA in the Occ reached a maximum increase during 20 min post-stimulation and remained higher than baseline values at 220 min post-stimulation. Local perfusion with tetrodotoxin (TTX, 10 ?M) markedly reduced baseline NA and DA in the mPFC and Occ and totally suppressed the effect of electrical stimulation in both areas. A sequence of five 20 min stimulations at 20 min intervals were delivered to the LC. Each stimulus increased NA to the same extent and duration as the first stimulus, whereas DA remained elevated at the time next stimulus was delivered, so that baseline DA progressively increased in the mPFC and Occ to reach about 130 and 200% the initial level, respectively. In the presence of the NA transport (NAT) blocker desipramine (DMI, 100 ?M), multiple LC stimulation still increased extracellular NA and DA levels. Electrical stimulation of the LC increased NA levels in the homolateral caudate nucleus, but failed to modify DA level. Conclusion The results confirm and extend that LC stimulation induces a concomitant release of DA and NA in the mPFC and Occ. The different time-course of LC-induced elevation of DA and NA suggests that their co-release may be differentially controlled. PMID:15865626

  5. Evidence of Ferrichromite of Extraterrestrial Origin by Means of Rock Magnetic Studies from the LOC-9 Drill Core (lockne Crater, Sweden)

    NASA Astrophysics Data System (ADS)

    Melero Asensio, I.; Martin Hernandez, F.; Örmo, J.; Guerrero-Suarez, S.

    2011-12-01

    The Lockne (456 Ma) marine-target impact structure is a concentric with a 7.5 km wide inner crater in the crystalline basement, and an up to 3.5 km wide brim where the sedimentary target succession is partially or completely removed. Much of the crater is covered by sediments deposited during the resurge of seawater, as well as by secular sediments. The LOC-9 core is 31.04m long and was drilled into the crystalline crater brim and the proximal ejecta flap of the inner crater. The ejecta flap at this location is mainly brecciated basalt with some blending of dark shale just at the contact with the more intact granitic basement. Published studies of the resurge deposits by Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) show the presence of ferrichromite particles interpreted to be meteoritic material. Here we combine complete rock magnetic characterization of the magnetic signal along the core with the characterization of the ferrichromite phase. Rock magnetic analysis includes low-field magnetic susceptibility, hysteresis loops, isothermal remanent magnetization (IRM) acquisition curves, coercivity spectra derived from IRM acquisition curves, back field IRM demagnetization curves and thermomagnetic curves. Additionally, a compositional analysis of a magnetic extract with SEM-EDX was done in order to identify the dominant magnetic fraction. Magnetite and titanomagnetite with different Ti content are identified as the main carriers of the magnetic signal along the core, based on the thermomagnetic curves, the saturation magnetization measured in the hysteresis loops, and the IRM acquisition curves. Pyrite is indicated by the thermomagnetic curve at one location in the core. A high coercivity phase is also observed in some samples. The coercivity spectral analysis shows one single population of magnetic minerals that dominates the magnetic signal at a level where the magnetic susceptibility is particularly high. The median destructive field is consistent with values reported at positions in the core with lower susceptibility and the dispersion parameter is well constrained with average values suggesting no significant diagenesis. The level immediately above the brecciated basement is composed of a relatively high amount of target material. At this depth, thermomagnetic curves reveal the presence of a magnetic phase with low Curie unblocking temperature (˜ 100 °C). No evidence of transformation of goethite into hematite is noted, which suggests the ferrichromite to be of extraterrestrial origin. This exotic phase is characterized by rock magnetic parameters derived from thermomagnetic curves, IRM acquisition curves, and hysteresis loops. The estimated Curie temperature is also consistent with a 50% content Cr, as reported by previous SEM studies of material from the Lockne crater. We conclude that rock magnetic studies complement other methods in the detection of potential extraterrestrial component in impactites.

  6. 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

  7. Relationship between Stereoscopic Vision, Visual Perception, and Microstructure Changes of Corpus Callosum and Occipital White Matter in the 4-Year-Old Very Low Birth Weight Children

    PubMed Central

    Kwinta, Przemko; Herman-Sucharska, Izabela; Le?niak, Anna; Klimek, Ma?gorzata; Karcz, Paulina; Durlak, Wojciech; Nitecka, Magdalena; Dutkowska, Gra?yna; Kubatko-Zieli?ska, Anna; Romanowska-Dixon, Bo?ena; Pietrzyk, Jacek Józef

    2015-01-01

    Aim. To assess the relationship between stereoscopic vision, visual perception, and microstructure of the corpus callosum (CC) and occipital white matter, 61 children born with a mean birth weight of 1024?g (SD 270?g) were subjected to detailed ophthalmologic evaluation, Developmental Test of Visual Perception (DTVP-3), and diffusion tensor imaging (DTI) at the age of 4. Results. Abnormal stereoscopic vision was detected in 16 children. Children with abnormal stereoscopic vision had smaller CC (CC length: 53 ± 6?mm versus 61 ± 4?mm; p < 0.01; estimated CC area: 314 ± 106?mm2 versus 446 ± 79?mm2; p < 0.01) and lower fractional anisotropy (FA) values in CC (FA value of rostrum/genu: 0.7 ± 0.09 versus 0.79 ± 0.07; p < 0.01; FA value of CC body: 0.74 ± 0.13 versus 0.82 ± 0.09; p = 0.03). We found a significant correlation between DTVP-3 scores, CC size, and FA values in rostrum and body. This correlation was unrelated to retinopathy of prematurity. Conclusions. Visual perceptive dysfunction in ex-preterm children without major sequelae of prematurity depends on more subtle changes in the brain microstructure, including CC. Role of interhemispheric connections in visual perception might be more complex than previously anticipated. PMID:26451381

  8. Discrimination of Visual Categories Based on Behavioral Relevance in Widespread Regions of Frontoparietal Cortex.

    PubMed

    Erez, Yaara; Duncan, John

    2015-09-01

    Allocating attentional resources to currently relevant information in a dynamically changing environment is critical to goal-directed behavior. Previous studies in nonhuman primates (NHPs) have demonstrated modulation of neural representations of stimuli, in particular visual categorizations, by behavioral significance in the lateral prefrontal cortex. In the human brain, a network of frontal and parietal regions, the "multiple demand" (MD) system, is involved in cognitive and attentional control. To test for the effect of behavioral significance on categorical discrimination in the MD system in humans, we adapted a previously used task in the NHP and used multivoxel pattern analysis for fMRI data. In a cued-detection categorization task, participants detected whether an image from one of two target visual categories was present in a display. Our results revealed that categorical discrimination is modulated by behavioral relevance, as measured by the distributed pattern of response across the MD network. Distinctions between categories with different behavioral status (e.g., a target and a nontarget) were significantly discriminated. Category distinctions that were not behaviorally relevant (e.g., between two targets) were not discriminated. Other aspects of the task that were orthogonal to the behavioral decision did not modulate categorical discrimination. In a high visual region, the lateral occipital complex, modulation by behavioral relevance was evident in its posterior subregion but not in the anterior subregion. The results are consistent with the view of the MD system as involved in top-down attentional and cognitive control by selective coding of task-relevant discriminations. Significance statement: Control of cognitive demands fundamentally involves flexible allocation of attentional resources depending on a current behavioral context. Essential to such a mechanism is the ability to select currently relevant information and at the same time filter out information that is irrelevant. In an fMRI study, we measured distributed patterns of activity for objects from different visual categories while manipulating the behavioral relevance of the categorical distinctions. In a network of frontal and parietal cortical regions, the multiple-demand (MD) network, patterns reflected category distinctions that were relevant to behavior. Patterns could not be used to make task-irrelevant category distinctions. These findings demonstrate the ability of the MD network to implement complex goal-directed behavior by focused attention. PMID:26354907

  9. Elevation of the petrous bone caused by hyperplasia of the occipital bone presenting as hemifacial spasm: diagnostic values of magnetic resonance imaging and three-dimensional computed tomographic images in a bone anomaly.

    PubMed

    Tanaka, A; Tanaka, T; Irie, Y; Yoshinaga, S; Tomonaga, M

    1990-12-01

    A case of elevation of the petrous bone due to hyperplasia of the occipital bone presenting as hemifacial spasm is reported. A 44-year-old man sought treatment for twitching of the buccal muscles on the right side that progressed rapidly in severity within 2 weeks of the onset. The anatomical details of the petrous and occipital bones were delineated clearly by computed tomographic scans of a bone window level. Details of the brain stem were shown by magnetic resonance images. The bone anomaly was displayed more realistically by three-dimensional computed tomographic reconstructions. The faithful representation of structures with these radiological studies should be mandatory, to prepare the surgical planning of such a complicated bone anomaly. PMID:2274120

  10. Direct recordings in human cortex reveal the dynamics of gamma-band [50-150 Hz] activity during pursuit eye movement control.

    PubMed

    Bastin, Julien; Lebranchu, Pierre; Jerbi, Karim; Kahane, Philippe; Orban, Guy; Lachaux, Jean-Philippe; Berthoz, Alain

    2012-10-15

    The time course of neural activity in human brain regions involved in mediating pursuit eye movements is unclear. To address this question, we recorded intracerebral electroencephalography activity in eight epileptic patients while they performed a pursuit task that dissociates reactive, predictive and inhibited pursuits. A sustained gamma band (50-150 Hz) activity corresponding to pursuit maintenance was observed in the pursuit (and not saccade) area of the frontal eye field (FEF), in the ventral intraparietal sulcus (VIPS) and in occipital areas. The latency of gamma increase was found to precede target onset in FEF and VIPS, suggesting that those areas could also be involved during pursuit preparation/initiation. During pursuit inhibition, a sustained gamma band response was observed within prefrontal areas (pre-supplementary-motor-area, dorso-lateral prefrontal and frontopolar cortex). This study describes for the first time the dynamics of the neural activity in four areas of the pursuit system, not previously available in humans. These findings provide novel timing constraints to current models of the human pursuit system and establish the relevance of direct recordings to precisely relate eye movement behavior with neural activity in humans. PMID:22819950

  11. Regulation of somatosensory cortex development downstream of glutamate 

    E-print Network

    Petrie, Anne

    2009-01-01

    Development of the rodent somatosensory cortex is well characterised and involves activity-dependent mechanisms that occur during the first postnatal week. Glutamate is a key neurotransmitter responsible for signalling ...

  12. Superimposed Hemifields in Primary Visual Cortex of Achiasmic Individuals

    E-print Network

    Sinha, Pawan

    In the rare condition of achiasma, the visual cortex in each hemisphere receives information from both halves of the visual field. How is this “doubling” of information accommodated in V1? In this issue of Neuron, Hoffmann ...

  13. Retinotopic Mapping of the Visual Cortex Using Functional Magnetic Resonance

    E-print Network

    Yantis, Steven

    was used to define the site and stability of fixation and the area of dense scotoma. Functional magnetic to perform retinotopic map- ping­that is, to determine which areas in the visual cortex are stimulated

  14. Multiple dynamic representations in the motor cortex during sensorimotor learning

    PubMed Central

    Huber, D.; Gutnisky, D.A.; Peron, S.; O’Connor, D. H.; Wiegert, J. S.; Tian, L.; Oertner, G.; Looger, L. L.; Svoboda, K.

    2015-01-01

    Summary The mechanisms linking sensation and action during learning are poorly understood. Layer 2/3 neurons in the motor cortex might participate in sensorimotor integration and learning; they receive input from sensory cortex, and excite deep layer neurons, which control movement. Here we imaged activity in the same set of layer 2/3 neurons in the motor cortex over weeks, while mice learned to detect objects with their whiskers and report detection with licking. Spatially intermingled neurons represented sensory (touch) and motor behaviors (whisking, licking). With learning, the population-level representation of task-related licking strengthened. In trained mice, population-level representations were redundant and stable, despite dynamism of single-neuron representations. The activity of a subpopulation of neurons was consistent with driving licking triggered by touch. Our results suggest that ensembles of motor cortex neurons couple sensory input to multiple, related motor programs during learning. PMID:22538608

  15. 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...

  16. Investigating the maintenance of the mouse definitive adrenal cortex 

    E-print Network

    Zhao, Xin

    2013-11-29

    The adrenal gland is an important endocrine organ, protecting the body against acute and chronic stress. The adrenal cortex consists of three morphologically and functionally distinct zones: the outer zona glomerulosa (zG), the zona fasciculata (zF...

  17. Emergence of invariant representation of vocalizations in the auditory cortex.

    PubMed

    Carruthers, Isaac M; Laplagne, Diego A; Jaegle, Andrew; Briguglio, John J; Mwilambwe-Tshilobo, Laetitia; Natan, Ryan G; Geffen, Maria N

    2015-11-01

    An essential task of the auditory system is to discriminate between different communication signals, such as vocalizations. In everyday acoustic environments, the auditory system needs to be capable of performing the discrimination under different acoustic distortions of vocalizations. To achieve this, the auditory system is thought to build a representation of vocalizations that is invariant to their basic acoustic transformations. The mechanism by which neuronal populations create such an invariant representation within the auditory cortex is only beginning to be understood. We recorded the responses of populations of neurons in the primary and nonprimary auditory cortex of rats to original and acoustically distorted vocalizations. We found that populations of neurons in the nonprimary auditory cortex exhibited greater invariance in encoding vocalizations over acoustic transformations than neuronal populations in the primary auditory cortex. These findings are consistent with the hypothesis that invariant representations are created gradually through hierarchical transformation within the auditory pathway. PMID:26311178

  18. Role of the Primate Orbitofrontal Cortex in Mediating Anxious Temperament

    E-print Network

    Wisconsin at Madison, University of

    Role of the Primate Orbitofrontal Cortex in Mediating Anxious Temperament Ned H. Kalin, Steven E anxious temperament and is a risk factor for the development of anxiety and affective disorders. Studies temperament and its involvement in fear responses. Methods: Twelveadolescentrhesusmonkeyswerestudied

  19. The Laryngeal Motor Cortex: Its Organization and Connectivity

    PubMed Central

    Simonyan, Kristina

    2014-01-01

    Our ability to learn and control the motor aspects of complex laryngeal behaviors, such as speech and song, is modulated by the laryngeal motor cortex (LMC), which is situated in the area 4 of the primary motor cortex and establishes both direct and indirect connections with laryngeal motoneurons. In contrast, the LMC in monkeys is located in the area 6 of the premotor cortex, projects only indirectly to laryngeal motoneurons and its destruction has essentially no effect on production of species-specific calls. These differences in cytoarchitectonic location and connectivity may be a result of hominid evolution that led to the LMC shift from the phylogenetically “old” to “new” motor cortex in order to fulfill its paramount function, i.e., voluntary motor control of human speech and song production. PMID:24929930

  20. Pre-Attentive Segmentation in the Primary Visual Cortex

    E-print Network

    Li, Zhaoping

    1998-06-30

    Stimuli outside classical receptive fields have been shown to exert significant influence over the activities of neurons in primary visual cortexWe propose that contextual influences are used for pre-attentive visual ...

  1. Reliability and representational bandwidth in the auditory cortex.

    PubMed

    DeWeese, Michael R; Hromádka, Tomás; Zador, Anthony M

    2005-11-01

    It is unclear why there are so many more neurons in sensory cortex than in the sensory periphery. One possibility is that these "extra" neurons are used to overcome cortical noise and faithfully represent the acoustic stimulus. Another possibility is that even after overcoming cortical noise, there is "excess representational bandwidth" available and that this bandwidth is used to represent conjunctions of auditory and nonauditory information for computation. Here, we discuss recent data about neuronal reliability in auditory cortex showing that cortical noise may not be as high as was previously believed. Although at present, the data suggest that auditory cortex neurons can be more reliable than those in the visual cortex, we speculate that the principles governing cortical computation are universal and that visual and other cortical areas can also exploit strategies based on similarly high-fidelity activity. PMID:16269364

  2. Sparse Representation of Sounds in the Unanesthetized Auditory Cortex

    E-print Network

    Zadorlab, Tony

    Sparse Representation of Sounds in the Unanesthetized Auditory Cortex Toma´s Hroma´dka1 , Michael R subsets of highly active neurons. Citation: Hroma´dka T, DeWeese MR, Zador AM (2008) Sparse representation

  3. Vision: how to train visual cortex to predict reward time.

    PubMed

    Hangya, Balázs; Kepecs, Adam

    2015-06-15

    Little is known about how the brain learns to anticipate the timing of reward. A new study demonstrates that optogenetic activation of basal forebrain input is sufficient to train reward timing activity in the primary visual cortex. PMID:26079076

  4. Decoding cognitive control in human parietal cortex Michael Esterman1

    E-print Network

    Yantis, Steven

    Decoding cognitive control in human parietal cortex Michael Esterman1 , Yu-Chin Chiu, Benjamin J reconfiguration of the mind/brain in one or more domains is required as goals and environmental demands change

  5. Antidepressant Effect of Optogenetic Stimulation of the Medial Prefrontal Cortex

    E-print Network

    Covington III, Herbert E.

    Brain stimulation and imaging studies in humans have highlighted a key role for the prefrontal cortex in clinical depression; however, it remains unknown whether excitation or inhibition of prefrontal cortical neuronal ...

  6. Visual Field Map Clusters in Macaque Extrastriate Visual Cortex

    E-print Network

    Kolster, Hauke

    The macaque visual cortex contains >30 different functional visual areas, yet surprisingly little is known about the underlying organizational principles that structure its components into a complete "visual" unit. A recent ...

  7. Selectivity of Local Field Potentials in Macaque Inferior Temporal Cortex

    E-print Network

    Kreiman, Gabriel

    2004-09-21

    While single neurons in inferior temporal (IT) cortex show differential responses to distinct complex stimuli, little is known about the responses of populations of neurons in IT. We recorded single electrode data, including ...

  8. 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, ...

  9. 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.

  10. Stream segregation in the anesthetized auditory cortex

    PubMed Central

    Scholes, Chris; Palmer, Alan R.; Sumner, Christian J.

    2015-01-01

    Auditory stream segregation describes the way that sounds are perceptually segregated into groups or streams on the basis of perceptual attributes such as pitch or spectral content. For sequences of pure tones, segregation depends on the tones' proximity in frequency and time. In the auditory cortex (and elsewhere) responses to sequences of tones are dependent on stimulus conditions in a similar way to the perception of these stimuli. However, although highly dependent on stimulus conditions, perception is also clearly influenced by factors unrelated to the stimulus, such as attention. Exactly how ‘bottom-up’ sensory processes and non-sensory ‘top-down’ influences interact is still not clear. Here, we recorded responses to alternating tones (ABAB …) of varying frequency difference (FD) and rate of presentation (PR) in the auditory cortex of anesthetized guinea-pigs. These data complement previous studies, in that top-down processing resulting from conscious perception should be absent or at least considerably attenuated. Under anesthesia, the responses of cortical neurons to the tone sequences adapted rapidly, in a manner sensitive to both the FD and PR of the sequences. While the responses to tones at frequencies more distant from neuron best frequencies (BFs) decreased as the FD increased, the responses to tones near to BF increased, consistent with a release from adaptation, or forward suppression. Increases in PR resulted in reductions in responses to all tones, but the reduction was greater for tones further from BF. Although asymptotically adapted responses to tones showed behavior that was qualitatively consistent with perceptual stream segregation, responses reached asymptote within 2 s, and responses to all tones were very weak at high PRs (>12 tones per second). A signal-detection model, driven by the cortical population response, made decisions that were dependent on both FD and PR in ways consistent with perceptual stream segregation. This included showing a range of conditions over which decisions could be made either in favor of perceptual integration or segregation, depending on the model ‘decision criterion’. However, the rate of ‘build-up’ was more rapid than seen perceptually, and at high PR responses to tones were sometimes so weak as to be undetectable by the model. Under anesthesia, adaptation occurs rapidly, and at high PRs tones are generally poorly represented, which compromises the interpretation of the experiment. However, within these limitations, these results complement experiments in awake animals and humans. They generally support the hypothesis that ‘bottom-up’ sensory processing plays a major role in perceptual organization, and that processes underlying stream segregation are active in the absence of attention. PMID:26163899

  11. Stream segregation in the anesthetized auditory cortex.

    PubMed

    Scholes, Chris; Palmer, Alan R; Sumner, Christian J

    2015-10-01

    Auditory stream segregation describes the way that sounds are perceptually segregated into groups or streams on the basis of perceptual attributes such as pitch or spectral content. For sequences of pure tones, segregation depends on the tones' proximity in frequency and time. In the auditory cortex (and elsewhere) responses to sequences of tones are dependent on stimulus conditions in a similar way to the perception of these stimuli. However, although highly dependent on stimulus conditions, perception is also clearly influenced by factors unrelated to the stimulus, such as attention. Exactly how 'bottom-up' sensory processes and non-sensory 'top-down' influences interact is still not clear. Here, we recorded responses to alternating tones (ABAB …) of varying frequency difference (FD) and rate of presentation (PR) in the auditory cortex of anesthetized guinea-pigs. These data complement previous studies, in that top-down processing resulting from conscious perception should be absent or at least considerably attenuated. Under anesthesia, the responses of cortical neurons to the tone sequences adapted rapidly, in a manner sensitive to both the FD and PR of the sequences. While the responses to tones at frequencies more distant from neuron best frequencies (BFs) decreased as the FD increased, the responses to tones near to BF increased, consistent with a release from adaptation, or forward suppression. Increases in PR resulted in reductions in responses to all tones, but the reduction was greater for tones further from BF. Although asymptotically adapted responses to tones showed behavior that was qualitatively consistent with perceptual stream segregation, responses reached asymptote within 2 s, and responses to all tones were very weak at high PRs (>12 tones per second). A signal-detection model, driven by the cortical population response, made decisions that were dependent on both FD and PR in ways consistent with perceptual stream segregation. This included showing a range of conditions over which decisions could be made either in favor of perceptual integration or segregation, depending on the model 'decision criterion'. However, the rate of 'build-up' was more rapid than seen perceptually, and at high PR responses to tones were sometimes so weak as to be undetectable by the model. Under anesthesia, adaptation occurs rapidly, and at high PRs tones are generally poorly represented, which compromises the interpretation of the experiment. However, within these limitations, these results complement experiments in awake animals and humans. They generally support the hypothesis that 'bottom-up' sensory processing plays a major role in perceptual organization, and that processes underlying stream segregation are active in the absence of attention. PMID:26163899

  12. A functional microcircuit for cat visual cortex.

    PubMed Central

    Douglas, R J; Martin, K A

    1991-01-01

    1. We have studied in vivo the intracellular responses of neurones in cat visual cortex to electrical pulse stimulation of the cortical afferents and have developed a microcircuit that simulates much of the experimental data. 2. Inhibition and excitation are not separable events, because individual neurones are embedded in microcircuits that contribute strong population effects. Synchronous electrical activation of the cortex inevitably set in motion a sequence of excitation and inhibition in every neurone we recorded. The temporal form of this response depends on the cortical layer in which the neurone is located. Superficial layer (layers 2+3) pyramidal neurones show a more marked polysynaptic excitatory phase than the pyramids of the deep layers (layers 5+6). 3. Excitatory effects on pyramidal neurones, particularly the superficial layer pyramids, are in general not due to monosynaptic input from thalamus, but polysynaptic input from cortical pyramids. Since the thalamic input is transient it does not provide the major, sustained excitation arriving at any cortical neurone. Instead the intracortical excitatory connections provide the major component of the excitation. 4. The polysynaptic excitatory response would be sustained well after the stimulus, were it not for the suppressive effect of intracortical inhibition induced by the pulse stimulation. 5. Intracellular recording combined with ionophoresis of gamma-aminobutyric acid (GABA) agonists and antagonists showed that intracortical inhibition is mediated by GABAA and GABAB receptors. The GABAA component occurs in the early phase of the impulse response. It is reflected in the strong hyperpolarization that follows the excitatory response and lasts about 50 ms. The GABAB component occurs in the late phase of the response, and is reflected in a sustained hyperpolarization that lasts some 200-300 ms. Both components are seen in all cortical pyramidal neurones. However, the GABAA component appears more powerful in deep layer pyramids than superficial layer pyramids. 6. The microcircuit simulates with good fidelity the above data from experiments in vivo and provides a novel explantation for the apparent lack of significant inhibition during visual stimulation. The basic circuit may be common to all cortical areas studied and thus the microcircuit may be a 'canonical' microcircuit for neocortex. PMID:1666655

  13. 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

  14. Spatial processing in the auditory cortex of the macaque monkey

    NASA Astrophysics Data System (ADS)

    Recanzone, Gregg H.

    2000-10-01

    The patterns of cortico-cortical and cortico-thalamic connections of auditory cortical areas in the rhesus monkey have led to the hypothesis that acoustic information is processed in series and in parallel in the primate auditory cortex. Recent physiological experiments in the behaving monkey indicate that the response properties of neurons in different cortical areas are both functionally distinct from each other, which is indicative of parallel processing, and functionally similar to each other, which is indicative of serial processing. Thus, auditory cortical processing may be similar to the serial and parallel "what" and "where" processing by the primate visual cortex. If "where" information is serially processed in the primate auditory cortex, neurons in cortical areas along this pathway should have progressively better spatial tuning properties. This prediction is supported by recent experiments that have shown that neurons in the caudomedial field have better spatial tuning properties than neurons in the primary auditory cortex. Neurons in the caudomedial field are also better than primary auditory cortex neurons at predicting the sound localization ability across different stimulus frequencies and bandwidths in both azimuth and elevation. These data support the hypothesis that the primate auditory cortex processes acoustic information in a serial and parallel manner and suggest that this may be a general cortical mechanism for sensory perception.

  15. 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

  16. Behavior Modulates Effective Connectivity between Cortex and Striatum

    PubMed Central

    Nakhnikian, Alexander; Rebec, George V.; Grasse, Leslie M.; Dwiel, Lucas L.; Shimono, Masanori; Beggs, John M.

    2014-01-01

    It has been notoriously difficult to understand interactions in the basal ganglia because of multiple recurrent loops. Another complication is that activity there is strongly dependent on behavior, suggesting that directional interactions, or effective connections, can dynamically change. A simplifying approach would be to examine just the direct, monosynaptic projections from cortex to striatum and contrast this with the polysynaptic feedback connections from striatum to cortex. Previous work by others on effective connectivity in this pathway indicated that activity in cortex could be used to predict activity in striatum, but that striatal activity could not predict cortical activity. However, this work was conducted in anesthetized or seizing animals, making it impossible to know how free behavior might influence effective connectivity. To address this issue, we applied Granger causality to local field potential signals from cortex and striatum in freely behaving rats. Consistent with previous results, we found that effective connectivity was largely unidirectional, from cortex to striatum, during anesthetized and resting states. Interestingly, we found that effective connectivity became bidirectional during free behaviors. These results are the first to our knowledge to show that striatal influence on cortex can be as strong as cortical influence on striatum. In addition, these findings highlight how behavioral states can affect basal ganglia interactions. Finally, we suggest that this approach may be useful for studies of Parkinson's or Huntington's diseases, in which effective connectivity may change during movement. PMID:24618981

  17. Cortex Integrity Relevance in Muscle Synergies in Severe Chronic Stroke

    PubMed Central

    García-Cossio, Eliana; Broetz, Doris; Birbaumer, Niels; Ramos-Murguialday, Ander

    2014-01-01

    Background: Recent experimental evidence has indicated that the motor system coordinates muscle activations through a linear combination of muscle synergies that are specified at the spinal or brainstem networks level. After stroke upper limb impairment is characterized by abnormal patterns of muscle activations or synergies. Objective: This study aimed at characterizing the muscle synergies in severely affected chronic stroke patients. Furthermore, the influence of integrity of the sensorimotor cortex on synergy modularity and its relation with motor impairment was evaluated. Methods: Surface electromyography from 33 severely impaired chronic stroke patients was recorded during 6 bilateral movements. Muscle synergies were extracted and synergy patterns were correlated with motor impairment scales. Results: Muscle synergies extracted revealed different physiological patterns dependent on the preservation of the sensorimotor cortex. Patients without intact sensorimotor cortex showed a high preservation of muscle synergies. On the contrary, patients with intact sensorimotor cortex showed poorer muscle synergies preservation and an increase in new generated synergies. Furthermore, the preservation of muscle synergies correlated positively with hand functionality in patients with intact sensorimotor cortex and subcortical lesions only. Conclusion: Our results indicate that severely paralyzed chronic stroke patient with intact sensorimotor cortex might sculpt new synergy patterns as a response to maladaptive compensatory strategies. PMID:25294998

  18. Medial cortex activity, self-reflection and depression

    PubMed Central

    Nolen-Hoeksema, Susan; Mitchell, Karen J.; Levin, Yael

    2009-01-01

    Using functional magnetic resonance imaging, we investigated neural activity associated with self-reflection in depressed [current major depressive episode (MDE)] and healthy control participants, focusing on medial cortex areas previously shown to be associated with self-reflection. Both the MDE and healthy control groups showed greater activity in anterior medial cortex (medial frontal gyrus, anterior cingulate gyrus) when cued to think about hopes and aspirations compared with duties and obligations, and greater activity in posterior medial cortex (precuneus, posterior cingulate) when cued to think about duties and obligations (Experiment 1). However, the MDE group showed less activity than controls in the same area of medial frontal cortex when self-referential cues were more ambiguous with respect to valence (Experiment 2), and less deactivation in a non-self-referential condition in both experiments. Furthermore, individual differences in rumination were positively correlated with activity in both anterior and posterior medial cortex during non-self-referential conditions. These results provide converging evidence for a dissociation of anterior and posterior medial cortex depending on the focus of self-relevant thought. They also provide neural evidence consistent with behavioral findings that depression is associated with disruption of positively valenced thoughts in response to ambiguous cues, and difficulty disengaging from self-reflection when it is appropriate to do so. PMID:19620180

  19. Spatial Frequency Maps in Cat Visual Cortex

    PubMed Central

    Issa, Naoum P.; Trepel, Christopher; Stryker, Michael P.

    2008-01-01

    Neurons in the primary visual cortex (V1) respond preferentially to stimuli with distinct orientations and spatial frequencies. Although the organization of orientation selectivity has been thoroughly described, the arrangement of spatial frequency (SF) preference in V1 is controversial. Several layouts have been suggested, including laminar, columnar, clustered, pinwheel, and binary (high and low SF domains). We have reexamined the cortical organization of SF preference by imaging intrinsic cortical signals induced by stimuli of various orientations and SFs. SF preference maps, produced from optimally oriented stimuli, were verified using targeted microelectrode recordings. We found that a wide range of SFs is represented independently and mostly continuously within V1. Domains with SF preferences at the extremes of the SF continuum were separated by no more than 3/4 mm (conforming to the hypercolumn description of cortical organization) and were often found at pinwheel center singularities in the cortical map of orientation preference. The organization of cortical maps permits nearly all combinations of orientation and SF preference to be represented in V1, and the overall arrangement of SF preference in V1 suggests that SF-specific adaptation effects, found in psychophysical experiments, may be explained by local interactions within a given SF domain. By reanalyzing our data using a different definition of SF preference than is used in electrophysiological and psychophysical studies, we can reproduce the different SF organizations suggested by earlier studies. PMID:11069958

  20. Navigating actions through the rodent parietal cortex

    PubMed Central

    Whitlock, Jonathan R.

    2014-01-01

    The posterior parietal cortex (PPC) participates in a manifold of cognitive functions, including visual attention, working memory, spatial processing, and movement planning. Given the vast interconnectivity of PPC with sensory and motor areas, it is not surprising that neuronal recordings show that PPC often encodes mixtures of spatial information as well as the movements required to reach a goal. Recent work sought to discern the relative strength of spatial vs. motor signaling in PPC by recording single unit activity in PPC of freely behaving rats during selective changes in either the spatial layout of the local environment or in the pattern of locomotor behaviors executed during navigational tasks. The results revealed unequivocally a predominant sensitivity of PPC neurons to locomotor action structure, with subsets of cells even encoding upcoming movements more than 1 s in advance. In light of these and other recent findings in the field, I propose that one of the key contributions of PPC to navigation is the synthesis of goal-directed behavioral sequences, and that the rodent PPC may serve as an apt system to investigate cellular mechanisms for spatial motor planning as traditionally studied in humans and monkeys. PMID:24860475

  1. Microstimulation of inferotemporal cortex influences face categorization.

    PubMed

    Afraz, Seyed-Reza; Kiani, Roozbeh; Esteky, Hossein

    2006-08-10

    The inferior temporal cortex (IT) of primates is thought to be the final visual area in the ventral stream of cortical areas responsible for object recognition. Consistent with this hypothesis, single IT neurons respond selectively to highly complex visual stimuli such as faces. However, a direct causal link between the activity of face-selective neurons and face perception has not been demonstrated. In the present study of macaque monkeys, we artificially activated small clusters of IT neurons by means of electrical microstimulation while the monkeys performed a categorization task, judging whether noisy visual images belonged to 'face' or 'non-face' categories. Here we show that microstimulation of face-selective sites, but not other sites, strongly biased the monkeys' decisions towards the face category. The magnitude of the effect depended upon the degree of face selectivity of the stimulation site, the size of the stimulated cluster of face-selective neurons, and the exact timing of microstimulation. Our results establish a causal relationship between the activity of face-selective neurons and face perception. PMID:16878143

  2. Optogenetic dissection of medial prefrontal cortex circuitry

    PubMed Central

    Riga, Danai; Matos, Mariana R.; Glas, Annet; Smit, August B.; Spijker, Sabine; Van den Oever, Michel C.

    2014-01-01

    The medial prefrontal cortex (mPFC) is critically involved in numerous cognitive functions, including attention, inhibitory control, habit formation, working memory and long-term memory. Moreover, through its dense interconnectivity with subcortical regions (e.g., thalamus, striatum, amygdala and hippocampus), the mPFC is thought to exert top-down executive control over the processing of aversive and appetitive stimuli. Because the mPFC has been implicated in the processing of a wide range of cognitive and emotional stimuli, it is thought to function as a central hub in the brain circuitry mediating symptoms of psychiatric disorders. New optogenetics technology enables anatomical and functional dissection of mPFC circuitry with unprecedented spatial and temporal resolution. This provides important novel insights in the contribution of specific neuronal subpopulations and their connectivity to mPFC function in health and disease states. In this review, we present the current knowledge obtained with optogenetic methods concerning mPFC function and dysfunction and integrate this with findings from traditional intervention approaches used to investigate the mPFC circuitry in animal models of cognitive processing and psychiatric disorders. PMID:25538574

  3. Computational models of perirhinal cortex function.

    PubMed

    Cowell, Rosemary A

    2012-10-01

    I review seven models of the contribution of perirhinal cortex (PRC) or neighboring neocortical regions to cognition. Five of the models address recognition memory function (Sohal and Hasselmo (2000) Network 11:169-190; Bogacz et al. (2001) J Comput Neurosci 10:5-23; Bogacz and Brown (2003a) Neurocomputing 52:1-6; Norman and O'Reilly (2003) Psychol Rev 110:611-646; Cowell et al. (2006) J Neurosci 26:12186-12197) and two account for the role of PRC in visual discrimination learning (Bussey and Saksida (2002) Eur J Neurosci 15:355-364; Cowell et al. (2010b) J Cogn Neurosci 22:2460-2479). The models span a range of biological scales and target a variety of datasets, such that like for like comparison between them is not always possible. I lay out a novel framework for facilitating comparison by defining some general abstract principles concerning the organization of cognition in the brain about which all of the models make a statement. The controversies that are revealed by scrutinizing the models within this framework highlight the fundamental questions that remain to be answered by future research. Ultimately, it is by combining these disparate accounts to build a unified model that bridges several levels of biological scale and accounts for multiple psychological phenomena that a full account of PRC function will be achieved. PMID:22987674

  4. Effects of TMS to occipital face area on the perception of face viewpoint cued only by shape changes in the external contour of the face.

    PubMed

    Lawrence, Samuel; Keefe, Bruce; Vernon, Richard; Gouws, André; Brown, Holly; Wade, Alex; McKeefry, Declan; Morland, Antony

    2015-09-01

    Changes in the outer contour of a face act as a cue to face viewpoint, and these changes can be captured using radial frequency (RF) pattern stimuli (Wilson et al., 2000). The face viewpoint aftereffect (FVA) is a visual illusion where adaptation to a left-facing face causes a front-facing face to appear as right-facing and vice versa (Fang and He, 2005). The occipital face area (OFA) has been implicated in both the FVA (Fang et al., 2007) and early face processing (Haxby et al., 2000; Pitcher et al., 2007). We replicated the FVA using synthetic head outline RF pattern stimuli. We then applied transcranial magnetic stimulation (TMS) to OFA and a nearby shape processing area, LO2 (Silson et al., 2013), during viewpoint discriminations of the same stimuli following adaptation to a forward- or lateral-facing stimulus. TMS to OFA resulted in significantly worse viewpoint discrimination than TMS to LO2, however neither condition was significantly different from control conditions. It was therefore impossible to determine whether our effect of TMS on discrimination was attributable to a facilitation of performance from TMS to LO2, or an inhibition of performance from TMS to OFA. In addition we found no effect of TMS to any brain regions on the magnitude of the FVA. We conclude that our differential effect of TMS to LO2 and OFA on viewpoint discrimination likely indicates a causal role for OFA in the processing of shape cues to viewpoint, however more data will be acquired to further clarify our results. This would be consistent with Silson et al.'s (2013) suggestion of parallel mechanisms for orientation and shape processing in LO1 and LO2, respectively. We add a potential third parallel mechanism for shape information that is relevant to face processing in OFA. Meeting abstract presented at VSS 2015. PMID:26326120

  5. 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

  6. Decoding Sound and Imagery Content in Early Visual Cortex

    PubMed Central

    Vetter, Petra; Smith, Fraser W.; Muckli, Lars

    2014-01-01

    Summary Human early visual cortex was traditionally thought to process simple visual features such as orientation, contrast, and spatial frequency via feedforward input from the lateral geniculate nucleus (e.g., [1]). However, the role of nonretinal influence on early visual cortex is so far insufficiently investigated despite much evidence that feedback connections greatly outnumber feedforward connections [2–5]. Here, we explored in five fMRI experiments how information originating from audition and imagery affects the brain activity patterns in early visual cortex in the absence of any feedforward visual stimulation. We show that category-specific information from both complex natural sounds and imagery can be read out from early visual cortex activity in blindfolded participants. The coding of nonretinal information in the activity patterns of early visual cortex is common across actual auditory perception and imagery and may be mediated by higher-level multisensory areas. Furthermore, this coding is robust to mild manipulations of attention and working memory but affected by orthogonal, cognitively demanding visuospatial processing. Crucially, the information fed down to early visual cortex is category specific and generalizes to sound exemplars of the same category, providing evidence for abstract information feedback rather than precise pictorial feedback. Our results suggest that early visual cortex receives nonretinal input from other brain areas when it is generated by auditory perception and/or imagery, and this input carries common abstract information. Our findings are compatible with feedback of predictive information to the earliest visual input level (e.g., [6]), in line with predictive coding models [7–10]. PMID:24856208

  7. Role of somatosensory cortex in visuospatial attention.

    PubMed

    Balslev, Daniela; Odoj, Bartholomäus; Karnath, Hans-Otto

    2013-11-13

    The human somatosensory cortex (S1) is not among the brain areas usually associated with visuospatial attention. However, such a function can be presumed, given the recently identified eye proprioceptive input to S1 and the established links between gaze and attention. Here we investigated a rare patient with a focal lesion of the right postcentral gyrus that interferes with the processing of eye proprioception without affecting the ability to locate visual objects relative to her body or to execute eye movements. As a behavioral measure of spatial attention, we recorded fixation time during visual search and reaction time for visual discrimination in lateral displays. In contrast to a group of age-matched controls, the patient showed a gradient in looking time and in visual sensitivity toward the midline. Because an attention bias in the opposite direction, toward the ipsilesional space, occurs in patients with spatial neglect, in a second study, we asked whether the incidental coinjury of S1 together with the neglect-typical perisylvian lesion leads to a milder neglect. A voxelwise lesion behavior mapping analysis of a group of right-hemisphere stroke patients supported this hypothesis. The effect of an isolated S1 lesion on visual exploration and visual sensitivity as well as the modulatory role of S1 in spatial neglect suggest a role of this area in visuospatial attention. We hypothesize that the proprioceptive gaze signal in S1, although playing only a minor role in locating visual objects relative to the body, affects the allocation of attention in the visual space. PMID:24227740

  8. Neurovascular Coupling and Decoupling in the Cortex during Voluntary Locomotion

    PubMed Central

    Huo, Bing-Xing; Smith, Jared B.

    2014-01-01

    Hemodynamic signals are widely used to infer neural activity in the brain. We tested the hypothesis that hemodynamic signals faithfully report neural activity during voluntary behaviors by measuring cerebral blood volume (CBV) and neural activity in the somatosensory cortex and frontal cortex of head-fixed mice during locomotion. Locomotion induced a large and robust increase in firing rate and gamma-band (40–100 Hz) power in the local field potential in the limb representations in somatosensory cortex, and was accompanied by increases in CBV, demonstrating that hemodynamic signals are coupled with neural activity in this region. However, in the frontal cortex, CBV did not change during locomotion, but firing rate and gamma-band power both increased, indicating a decoupling of neural activity from the hemodynamic signal. These results show that hemodynamic signals are not faithful indicators of the mean neural activity in the frontal cortex during locomotion; thus, the results from fMRI and other hemodynamic imaging methodologies for studying neural processes must be interpreted with caution. PMID:25122897

  9. Infralimbic cortex activation and motivated arousal induce histamine release

    PubMed Central

    Forray, María Inés; Torrealba, Fernando

    2015-01-01

    Appetitive behaviours occur in a state of behavioural and physiological activation that allows the optimal performance of these goal-directed behaviours. Here, we tested the hypothesis that histamine neurons under the command of the infralimbic cortex are important to provide behavioural activation. Extracellular histamine and serotonin were measured by microdialysis of the medial prefrontal cortex in behaving rats in parallel with a picrotoxin microinjection into the infralimbic cortex. The injection aroused the rats behaviourally, increased histamine release and decreased serotonin levels. Inhibition of the infralimbic cortex with muscimol produced the opposite effects on neurotransmitter release. The behavioural activation induced by motivating hungry rats with caged food was paralleled by an immediate histamine release, whereas awakening induced by tapping their microdialysis bowl increased serotonin, but not histamine levels. In conclusion, picrotoxin injection into the infralimbic cortex produces behavioural activation together with histamine release; in a similar manner, induction of an appetitive state produced histamine release, likely related to increased behavioural activation characteristic of an appetitive behaviour. PMID:25746330

  10. Orosensory and Homeostatic Functions of the Insular Taste Cortex

    PubMed Central

    de Araujo, Ivan E.; Geha, Paul

    2014-01-01

    The gustatory aspect of the insular cortex is part of the brain circuit that controls ingestive behaviors based on chemosensory inputs. However, the sensory properties of foods are not restricted to taste and should also include salient features such as odor, texture, temperature, and appearance. Therefore, it is reasonable to hypothesize that specialized circuits within the central taste pathways must be involved in representing several other oral sensory modalities in addition to taste. In this review, we evaluate current evidence indicating that the insular gustatory cortex functions as an integrative circuit, with taste-responsive regions also showing heightened sensitivity to olfactory, somatosensory, and even visual stimulation. We also review evidence for modulation of taste-responsive insular areas by changes in physiological state, with taste-elicited neuronal responses varying according to the nutritional state of the organism. We then examine experimental support for a functional map within the insular cortex that might reflect the various sensory and homeostatic roles associated with this region. Finally, we evaluate the potential role of the taste insular cortex in weight-gain susceptibility. Taken together, the current experimental evidence favors the view that the insular gustatory cortex functions as an orosensory integrative system that not only enables the formation of complex flavor representations but also mediates their modulation by the internal state of the body, playing therefore a central role in food intake regulation. PMID:25485032

  11. A common somaesthetic pathway to red nucleus and motor cortex.

    PubMed

    Padel, Y; Relova, J L

    1988-01-01

    Comparable short latency somaesthetic responses have been observed in the red nucleus and the motor cortex. Since previous experiments showed that a ventral spinal ascending pathway could account for red nucleus responses, the present experiments were designed to establish whether the same pathway could also transmit the short latency peripheral inputs to motor cortex. Two experimental data argue in favour of a such organization: (1) Using the collision technique, it was demonstrated that somaesthetic responses recorded in red nucleus cells are transmitted by collaterals of ascending fibres ending in the ventrobasal thalamus. (2) Intracellular recordings from identified corticospinal cells were performed on cats acutely prepared on section of the brachium conjunctivum and the dorsal columns of the spinal cord. Cortico-cortical connections to motor cortex were also eliminated by lesions of the ipsilateral sensory cortex and contralateral motor cortex. With this preparation it is still possible to record postsynaptic potentials after stimulation of primary afferent fibres in the dorsal columns, caudally to their section. The existence of these somaesthetic parallel inputs to rubro- and corticospinal cells suggest that the ongoing movement might be corrected on-line by these two pathways. PMID:3382509

  12. The orbitofrontal cortex: novelty, deviation from expectation, and memory.

    PubMed

    Petrides, Michael

    2007-12-01

    The orbitofrontal cortex is strongly connected with limbic areas of the medial temporal lobe that are critically involved in the establishment of declarative memories (entorhinal and perirhinal cortex and the hippocampal region) as well as the amygdala and the hypothalamus that are involved in emotional and motivational states. The present article reviews evidence regarding the role of the orbitofrontal cortex in the processing of novel information, breaches of expectation, and memory. Functional neuroimaging evidence is provided that there is a difference between the anterior and posterior orbitofrontal cortex in such processing. Exposure to novel information gives rise to a selective increase of activity in the granular anterior part of the orbitofrontal cortex (area 11) and this activity increases when subjects attempt to encode this information in memory. If the stimuli violate expectations (e.g., inspection of graffiti-like stimuli in the context of other regular stimuli) or are unpleasant (i.e., exposure to the sounds of car crashes), there is increased response in the posteromedial agranular/dysgranular area 13 of the orbitofrontal region. The anatomic data provide a framework within which to understand these functional neuroimaging findings. PMID:17872393

  13. Major glutamatergic projection from subplate into visual cortex during development.

    PubMed

    Finney, E M; Stone, J R; Shatz, C J

    1998-08-17

    Subplate neurons, the first neurons of the cerebral cortex to differentiate and mature, are thought to be essential for the formation of connections between thalamus and cortex, such as the system of ocular dominance columns within layer 4 of visual cortex. To learn more about the requirement for subplate neurons in the formation of thalamocortical connections, we have sought to identify the neurotransmitters and peptides expressed by the specific class of subplate neurons that sends axonal projections into the overlying visual cortex. To label retrogradely subplate neurons, fluorescent latex microspheres were injected into primary visual cortex of postnatal day 28 ferrets, just prior to the onset of ocular dominance column formation. Subsequently, neurons were immunostained with antibodies against glutamate, glutamic acid decarboxylase (GAD-67), parvalbumin, neuropeptide Y (NPY), somatostatin (SRIF), or nitric oxide synthase (NOS). Retrograde labeling results indicate that the majority of subplate neurons projecting into the cortical plate reside in the upper half of the subplate. Combined immunostaining and microsphere labeling reveal that about half of cortically projecting subplate neurons are glutamatergic; most microsphere-labeled subplate neurons do not stain for GAD-67, parvalbumin, NPY, SRIF, or NOS. These observations suggest that subplate neurons can provide a significant glutamatergic synaptic input to the cortical plate, including the neurons of layer 4. If so, excitation from the axons of subplate neurons may be required in addition to that from lateral geniculate nucleus neurons for the activity-dependent synaptic interactions that lead to the formation of ocular dominance columns during development. PMID:9703030

  14. Electrocorticography Reveals Enhanced Visual Cortex Responses to Visual Speech.

    PubMed

    Schepers, Inga M; Yoshor, Daniel; Beauchamp, Michael S

    2015-11-01

    Human speech contains both auditory and visual components, processed by their respective sensory cortices. We test a simple model in which task-relevant speech information is enhanced during cortical processing. Visual speech is most important when the auditory component is uninformative. Therefore, the model predicts that visual cortex responses should be enhanced to visual-only (V) speech compared with audiovisual (AV) speech. We recorded neuronal activity as patients perceived auditory-only (A), V, and AV speech. Visual cortex showed strong increases in high-gamma band power and strong decreases in alpha-band power to V and AV speech. Consistent with the model prediction, gamma-band increases and alpha-band decreases were stronger for V speech. The model predicts that the uninformative nature of the auditory component (not simply its absence) is the critical factor, a prediction we tested in a second experiment in which visual speech was paired with auditory white noise. As predicted, visual speech with auditory noise showed enhanced visual cortex responses relative to AV speech. An examination of the anatomical locus of the effects showed that all visual areas, including primary visual cortex, showed enhanced responses. Visual cortex responses to speech are enhanced under circumstances when visual information is most important for comprehension. PMID:24904069

  15. Responses of primate frontal cortex neurons during natural vocal communication.

    PubMed

    Miller, Cory T; Thomas, A Wren; Nummela, Samuel U; de la Mothe, Lisa A

    2015-08-01

    The role of primate frontal cortex in vocal communication and its significance in language evolution have a controversial history. While evidence indicates that vocalization processing occurs in ventrolateral prefrontal cortex neurons, vocal-motor activity has been conjectured to be primarily subcortical and suggestive of a distinctly different neural architecture from humans. Direct evidence of neural activity during natural vocal communication is limited, as previous studies were performed in chair-restrained animals. Here we recorded the activity of single neurons across multiple regions of prefrontal and premotor cortex while freely moving marmosets engaged in a natural vocal behavior known as antiphonal calling. Our aim was to test whether neurons in marmoset frontal cortex exhibited responses during vocal-signal processing and/or vocal-motor production in the context of active, natural communication. We observed motor-related changes in single neuron activity during vocal production, but relatively weak sensory responses for vocalization processing during this natural behavior. Vocal-motor responses occurred both prior to and during call production and were typically coupled to the timing of each vocalization pulse. Despite the relatively weak sensory responses a population classifier was able to distinguish between neural activity that occurred during presentations of vocalization stimuli that elicited an antiphonal response and those that did not. These findings are suggestive of the role that nonhuman primate frontal cortex neurons play in natural communication and provide an important foundation for more explicit tests of the functional contributions of these neocortical areas during vocal behaviors. PMID:26084912

  16. 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; Koizumi, Toshiyuki; Iida, Masaki; Iwai, Toshinori; Oguri, Senri; Yamamoto, Noriyuki; Itoh, Yoshiyuki; Kioi, Mitomu; Hirota, Makoto; Tohnai, Iwai

    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.

  17. Dental Occlusal Changes Induce Motor Cortex Neuroplasticity.

    PubMed

    Avivi-Arber, L; Lee, J-C; Sessle, B J

    2015-12-01

    Modification to the dental occlusion may alter oral sensorimotor functions. Restorative treatments aim to restore sensorimotor functions; however, it is unclear why some patients fail to adapt to the restoration and remain with sensorimotor complaints. The face primary motor cortex (face-M1) is involved in the generation and control of orofacial movements. Altered sensory inputs or motor function can induce face-M1 neuroplasticity. We took advantage of the continuous eruption of the incisors in Sprague-Dawley rats and used intracortical microstimulation (ICMS) to map the jaw and tongue motor representations in face-M1. Specifically, we tested the hypothesis that multiple trimming of the right mandibular incisor, to keep it out of occlusal contacts for 7 d, and subsequent incisor eruption and restoration of occlusal contacts, can alter the ICMS-defined features of jaw and tongue motor representations (i.e., neuroplasticity). On days 1, 3, 5, and 7, the trim and trim-recovered groups had 1 to 2 mm of incisal trimming of the incisor; a sham trim group had buccal surface trimming with no occlusal changes; and a naive group had no treatment. Systematic mapping was performed on day 8 in the naive, trim, and sham trim groups and on day 14 in the trim-recovered group. In the trim group, the tongue onset latency was shorter in the left face-M1 than in the right face-M1 (P < .001). In the trim-recovered group, the number of tongue sites and jaw/tongue overlapping sites was greater in the left face-M1 than in the right face-M1 (P = 0.0032, 0.0016, respectively), and the center of gravity was deeper in the left than in the right face-M1 (P = 0.026). Therefore, incisor trimming and subsequent restoration of occlusal contacts induced face-M1 neuroplasticity, reflected in significant disparities between the left and right face-M1 in some ICMS-defined features of the tongue motor representations. Such neuroplasticity may reflect or contribute to subjects' ability to adapt their oral sensorimotor functions to an altered dental occlusion. PMID:26310722

  18. 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

  19. 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

  20. Adaptation to sensory input tunes visual cortex to criticality

    NASA Astrophysics Data System (ADS)

    Shew, Woodrow L.; Clawson, Wesley P.; Pobst, Jeff; Karimipanah, Yahya; Wright, Nathaniel C.; Wessel, Ralf

    2015-08-01

    A long-standing hypothesis at the interface of physics and neuroscience is that neural networks self-organize to the critical point of a phase transition, thereby optimizing aspects of sensory information processing. This idea is partially supported by strong evidence for critical dynamics observed in the cerebral cortex, but the impact of sensory input on these dynamics is largely unknown. Thus, the foundations of this hypothesis--the self-organization process and how it manifests during strong sensory input--remain unstudied experimentally. Here we show in visual cortex and in a computational model that strong sensory input initially elicits cortical network dynamics that are not critical, but adaptive changes in the network rapidly tune the system to criticality. This conclusion is based on observations of multifaceted scaling laws predicted to occur at criticality. Our findings establish sensory adaptation as a self-organizing mechanism that maintains criticality in visual cortex during sensory information processing.

  1. Up states are rare in awake auditory cortex.

    PubMed

    Hromádka, Tomáš; Zador, Anthony M; DeWeese, Michael R

    2013-04-01

    The dynamics of subthreshold membrane potential provide insight into the organization of activity in neural circuits. In many brain areas, membrane potential is bistable, transiting between a relatively hyperpolarized down state and a depolarized up state. These up and down states, which have been proposed to play a number of computational roles, have mainly been studied in anesthetized and in vitro preparations. Here, we have used intracellular recordings to characterize the dynamics of membrane potential in the auditory cortex of awake rats. We find that long up states are rare in the awake auditory cortex, with only 0.4% of up states >500 ms. Most neurons displayed only brief up states (bumps) and spent on average ?1% of recording time in up states >500 ms. We suggest that the near absence of long up states in awake auditory cortex may reflect an adaptation to the rapid processing of auditory stimuli. PMID:23343898

  2. Up states are rare in awake auditory cortex

    PubMed Central

    Hromádka, Tomáš; Zador, Anthony M.

    2013-01-01

    The dynamics of subthreshold membrane potential provide insight into the organization of activity in neural circuits. In many brain areas, membrane potential is bistable, transiting between a relatively hyperpolarized down state and a depolarized up state. These up and down states, which have been proposed to play a number of computational roles, have mainly been studied in anesthetized and in vitro preparations. Here, we have used intracellular recordings to characterize the dynamics of membrane potential in the auditory cortex of awake rats. We find that long up states are rare in the awake auditory cortex, with only 0.4% of up states >500 ms. Most neurons displayed only brief up states (bumps) and spent on average ?1% of recording time in up states >500 ms. We suggest that the near absence of long up states in awake auditory cortex may reflect an adaptation to the rapid processing of auditory stimuli. PMID:23343898

  3. Dichotomy of functional organization in the mouse auditory cortex

    PubMed Central

    Bandyopadhyay, Sharba; Shamma, Shihab A.; Kanold, Patrick O.

    2010-01-01

    The sensory areas of the cerebral cortex possess multiple topographic representations of sensory dimensions. Gradient of frequency selectivity (tonotopy) is the dominant organizational feature in the primary auditory cortex, while other feature-based organizations are less well established. We probed the topographic organization of the mouse auditory cortex at the single cell level using in vivo two-photon Ca2+ imaging. Tonotopy was present on a large scale but was fractured on a fine scale. Intensity tuning, important in level-invariant representation, was observed in individual cells but was not topographically organized. The presence or near-absence of putative sub-threshold responses revealed a dichotomy in topographic organization. Inclusion of sub-threshold responses revealed a topographic clustering of neurons with similar response properties, while such clustering was absent in supra-threshold responses. This dichotomy indicates that groups of nearby neurons with locally shared inputs can perform independent parallel computations in ACX. PMID:20118924

  4. 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

  5. Similarities between GCS and human motor cortex: complex movement coordination

    NASA Astrophysics Data System (ADS)

    Rodríguez, Jose A.; Macias, Rosa; Molgo, Jordi; Guerra, Dailos

    2014-07-01

    The "Gran Telescopio de Canarias" (GTC1) is an optical-infrared 10-meter segmented mirror telescope at the ORM observatory in Canary Islands (Spain). The GTC control system (GCS), the brain of the telescope, is is a distributed object & component oriented system based on RT-CORBA and it is responsible for the management and operation of the telescope, including its instrumentation. On the other hand, the Human motor cortex (HMC) is a region of the cerebrum responsible for the coordination of planning, control, and executing voluntary movements. If we analyze both systems, as far as the movement control of their mechanisms and body parts is concerned, we can find extraordinary similarities in their architectures. Both are structured in layers, and their functionalities are comparable from the movement conception until the movement action itself: In the GCS we can enumerate the Sequencer high level components, the Coordination libraries, the Control Kit library and the Device Driver library as the subsystems involved in the telescope movement control. If we look at the motor cortex, we can also enumerate the primary motor cortex, the secondary motor cortices, which include the posterior parietal cortex, the premotor cortex, and the supplementary motor area (SMA), the motor units, the sensory organs and the basal ganglia. From all these components/areas we will analyze in depth the several subcortical regions, of the the motor cortex, that are involved in organizing motor programs for complex movements and the GCS coordination framework, which is composed by a set of classes that allow to the high level components to transparently control a group of mechanisms simultaneously.

  6. Motor and cognitive functions of the ventral premotor cortex.

    PubMed

    Rizzolatti, Giacomo; Fogassi, Leonardo; Gallese, Vittorio

    2002-04-01

    Recent data show that the ventral premotor cortex in both humans and monkeys has motor and cognitive functions. The cognitive functions include space perception, action understanding and imitation. The data also show a clear functional homology between monkey area F5 and human area 44. Preliminary evidence suggests that the ventral part of the lateral premotor cortex in humans may correspond to monkey area F4. A tentative map of the human lateral premotor areas founded on the reviewed evidence is presented. PMID:12015230

  7. Plasticity in the prefrontal cortex of adult rats

    PubMed Central

    Kolb, Bryan; Gibb, Robbin

    2015-01-01

    We review the plastic changes of the prefrontal cortex of the rat in response to a wide range of experiences including sensory and motor experience, gonadal hormones, psychoactive drugs, learning tasks, stress, social experience, metaplastic experiences, and brain injury. Our focus is on synaptic changes (dendritic morphology and spine density) in pyramidal neurons and the relationship to behavioral changes. The most general conclusion we can reach is that the prefrontal cortex is extremely plastic and that the medial and orbital prefrontal regions frequently respond very differently to the same experience in the same brain and the rules that govern prefrontal plasticity appear to differ for those of other cortical regions. PMID:25691857

  8. Transcranial Direct Current Stimulation of the Dorsolateral Prefrontal Cortex Modulates Repetition

    E-print Network

    Gosselin, Frédéric

    Transcranial Direct Current Stimulation of the Dorsolateral Prefrontal Cortex Modulates Repetition and learning of unfamiliar faces remains unclear. Transcranial direct current stimulation (tDCS) transiently Direct Current Stimulation of the Dorsolateral Prefrontal Cortex Modulates Repetition Suppression

  9. Computational Modeling of Orientation Tuning Dynamics in Monkey Primary Visual Cortex

    E-print Network

    Pugh, Mary

    Computational Modeling of Orientation Tuning Dynamics in Monkey Primary Visual Cortex M. C. Pugh, D, monkey, primary visual cortex, lay­ ers. 1 #12; Introduction How visual cells in the primary visual

  10. Anterior Cingulate Cortex Dysfunction in Attention-Deficit/Hyperactivity Disorder Revealed by fMRI

    E-print Network

    Bush, George

    Anterior Cingulate Cortex Dysfunction in Attention- Deficit/Hyperactivity Disorder Revealed by f disorder, cingulate cortex Introduction Attention-deficit/hyperactivity disorder is character- ized contribute to pro- ducing core features of attention-deficit/hyperactivity dis- order (ADHD), namely

  11. Reference Frames for Reach Planning in Macaque Dorsal Premotor Cortex Aaron P. Batista,1,2

    E-print Network

    Shenoy, Krishna V.

    Reference Frames for Reach Planning in Macaque Dorsal Premotor Cortex Aaron P. Batista,1,2 Gopal in macaque dorsal premotor cortex. J Neurophysiol 98: 966­983, 2007. First published June 20, 2007; doi:10

  12. Macaque Parahippocampal Functional Connectivity Functional Connectivity of the Macaque Posterior Parahippocampal Cortex4

    E-print Network

    Van Essen, David

    Macaque Parahippocampal Functional Connectivity 1 1 2 3 Functional Connectivity of the Macaque, Harvard Medical School13 14 Running Head: Macaque Parahippocampal Functional Connectivity15 16 Manuscript: functional connectivity; macaque; default network; parietal cortex;19 parahippocampal cortex; spontaneous

  13. Visual Cortex in Humans B A Wandell, S O Dumoulin, and A A Brewer,

    E-print Network

    Dumoulin, Serge O.

    Visual Cortex in Humans B A Wandell, S O Dumoulin, and A A Brewer, Stanford University, Stanford, CA, USA ã 2009 Elsevier Ltd. All rights reserved. Human visual cortex comprises 4­6 billion neurons human cortex can be identified by measuring visual field maps. The neurons within these areas have

  14. 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

  15. Representations of faces and body parts in macaque temporal cortex: A functional MRI study

    E-print Network

    Kastner, Sabine

    Representations of faces and body parts in macaque temporal cortex: A functional MRI study Mark A of macaque temporal cortex for representations of monkey faces and monkey body parts relative to man in macaque temporal cortex. non-human primate visual category representations Human and non-human primates

  16. Behavioral/Systems/Cognitive Looming Biases in Monkey Auditory Cortex

    E-print Network

    Ghazanfar, Asif

    Behavioral/Systems/Cognitive Looming Biases in Monkey Auditory Cortex Joost X. Maier and Asif A.Byrecordinglocalfieldpotentialandmultiunitspikingactivitywhilethesubjectswerepresentedwithauditorylooming and receding signals, we show here that auditory cortical activity was biased in magnitude toward looming, it is thought that animals have an evolved bias for detecting and re- sponding to looming events (Schiff et al

  17. Peripheral sounds rapidly activate visual cortex: evidence from electrocorticography.

    PubMed

    Brang, David; Towle, Vernon L; Suzuki, Satoru; Hillyard, Steven A; Di Tusa, Senneca; Dai, Zhongtian; Tao, James; Wu, Shasha; Grabowecky, Marcia

    2015-11-15

    Neurophysiological studies with animals suggest that sounds modulate activity in primary visual cortex in the presence of concurrent visual stimulation. Noninvasive neuroimaging studies in humans have similarly shown that sounds modulate activity in visual areas even in the absence of visual stimuli or visual task demands. However, the spatial and temporal limitations of these noninvasive methods prevent the determination of how rapidly sounds activate early visual cortex and what information about the sounds is relayed there. Using spatially and temporally precise measures of local synaptic activity acquired from depth electrodes in humans, we demonstrate that peripherally presented sounds evoke activity in the anterior portion of the contralateral, but not ipsilateral, calcarine sulcus within 28 ms of sound onset. These results suggest that auditory stimuli rapidly evoke spatially specific activity in visual cortex even in the absence of concurrent visual stimulation or visual task demands. This rapid auditory-evoked activation of primary visual cortex is likely to be mediated by subcortical pathways or direct cortical projections from auditory to visual areas. PMID:26334017

  18. 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…

  19. RAPID COMMUNICATION The Human Perirhinal Cortex and Recognition Memory

    E-print Network

    Squire, Larry R.

    ; visual perception; short-term memory; immediate memory Recognition memory refers to the ability, California ABSTRACT: The importance of the perirhinal cortex for visual recogni- tion memory performance in two amnesic patients by assessing recognition memory for complex visual stimuli across delays from 0

  20. INTRODUCTION The cerebral cortex is crucial for perceptual and higher

    E-print Network

    McConnell, Susan

    of the Small eye cortex. We tested this hypothesis by following the migration of cortical precursors after labelling them with bromodeoxyuridine in Small eye mice with a point mutation of Pax-6 (Sey, in which a stop and their developmental abilities could be assessed. MATERIALS AND METHODS Animals Mice were from isolated laboratory

  1. K+ waves in brain cortex visualized using a long-

    E-print Network

    Cai, Long

    -soluble, long-wavelength K+ sensor, TAC-Red, consisting of triazacryptand coupled to 3,6- bis+ waves in TAC-Red­stained brain cortex in mice during spreading depression, with velocity 4.4 ± 0.5 mm challenging and their use involves direct invasion of a single measurement site. A K+-sensing fluorescent dye

  2. Increased striatal functional connectivity with auditory cortex in tinnitus

    PubMed Central

    Hinkley, Leighton B.; Mizuiri, Danielle; Hong, OiSaeng; Nagarajan, Srikantan S.; Cheung, Steven W.

    2015-01-01

    Tinnitus is a common auditory perceptual disorder whose neural substrates are under intense debate. One physiologically based model posits the dorsal striatum to play a key role in gating auditory phantoms to perceptual awareness. Here, we directly test this model along with the roles of auditory and auditory-limbic networks in tinnitus non-invasively by comparing resting-state fMRI functional connectivity patterns in chronic tinnitus patients against matched control subjects without hearing loss. We assess resting-state functional connectivity of the caudate dorsal striatum (area LC), caudate head (CH), nucleus accumbens (NA), and primary auditory cortex (A1) to determine patterns of abnormal connectivity. In chronic tinnitus, increases in ipsilateral striatal–auditory cortical connectivity are found consistently only in area LC. Other patterns of increased connectivity are as follows: (1) right striatal area LC, A1, CH, and NA with parietal cortex, (2) left and right CHs with dorsal pre-frontal cortex, (3) NA and A1 with cerebellum, hippocampus, visual and ventral pre-frontal cortex. Those findings provide further support for a striatal gating model of tinnitus, where dysfunctionally permissive area LC enables auditory phantoms to reach perceptual awareness. PMID:26578924

  3. 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…

  4. Shape perception reduces activity in human primary visual cortex

    E-print Network

    Olshausen, Bruno

    (received for review April 25, 2002) Visual perception involves the grouping of individual elements of this perceptual simplifica- tion remains poorly understood. We used functional MRI to mea- sure activity cortex when elements formed coherent shapes, suggesting that activity in early visual areas is reduced

  5. Melting the Iceberg: Contrast Invariance in Visual Cortex

    E-print Network

    Poggio, Tomaso

    Melting the Iceberg: Contrast Invariance in Visual Cortex Matteo Carandini1, * 1 The Smith variations in stimulus contrast. Achieving this invariance is a challenge because of the iceberg effect limitation of the classic model is a behavior known since at least the 1970s as the ``iceberg effect'' (e

  6. 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

  7. Origins of choice-related activity in mouse somatosensory cortex.

    PubMed

    Yang, Hongdian; Kwon, Sung E; Severson, Kyle S; O'Connor, Daniel H

    2016-01-01

    During perceptual decisions about faint or ambiguous sensory stimuli, even identical stimuli can produce different choices. Spike trains from sensory cortex neurons can predict trial-to-trial variability in choice. Choice-related spiking is widely studied as a way to link cortical activity to perception, but its origins remain unclear. Using imaging and electrophysiology, we found that mouse primary somatosensory cortex neurons showed robust choice-related activity during a tactile detection task. Spike trains from primary mechanoreceptive neurons did not predict choices about identical stimuli. Spike trains from thalamic relay neurons showed highly transient, weak choice-related activity. Intracellular recordings in cortex revealed a prolonged choice-related depolarization in most neurons that was not accounted for by feed-forward thalamic input. Top-down axons projecting from secondary to primary somatosensory cortex signaled choice. An intracellular measure of stimulus sensitivity determined which neurons converted choice-related depolarization into spiking. Our results reveal how choice-related spiking emerges across neural circuits and within single neurons. PMID:26642088

  8. Cerebral Cortex doi:10.1093/cercor/bhn186

    E-print Network

    response to stimulus repetition is not uniform across brain regions, stimulus modalities, or task contextsCerebral Cortex doi:10.1093/cercor/bhn186 Repetition Suppression and Reactivation in Auditory stimulus repetition leads to a relative reduction in neural activity (repetition suppression), whereas

  9. Spindle neurons of the human anterior cingulate cortex

    NASA Technical Reports Server (NTRS)

    Nimchinsky, E. A.; Vogt, B. A.; Morrison, J. H.; Hof, P. R.; Bloom, F. E. (Principal Investigator)

    1995-01-01

    The human anterior cingulate cortex is distinguished by the presence of an unusual cell type, a large spindle neuron in layer Vb. This cell has been noted numerous times in the historical literature but has not been studied with modern neuroanatomic techniques. For instance, details regarding the neuronal class to which these cells belong and regarding their precise distribution along both ventrodorsal and anteroposterior axes of the cingulate gyrus are still lacking. In the present study, morphological features and the anatomic distribution of this cell type were studied using computer-assisted mapping and immunocytochemical techniques. Spindle neurons are restricted to the subfields of the anterior cingulate cortex (Brodmann's area 24), exhibiting a greater density in anterior portions of this area than in posterior portions, and tapering off in the transition zone between anterior and posterior cingulate cortex. Furthermore, a majority of the spindle cells at any level is located in subarea 24b on the gyral surface. Immunocytochemical analysis revealed that the neurofilament protein triple was present in a large percentage of these neurons and that they did not contain calcium-binding proteins. Injections of the carbocyanine dye DiI into the cingulum bundle revealed that these cells are projection neurons. Finally, spindle cells were consistently affected in Alzheimer's disease cases, with an overall loss of about 60%. Taken together, these observations indicate that the spindle cells of the human cingulate cortex represent a morphological subpopulation of pyramidal neurons whose restricted distribution may be associated with functionally distinct areas.

  10. Unconscious processing of orientation and color without primary visual cortex

    E-print Network

    Zhu, Zhigang

    Unconscious processing of orientation and color without primary visual cortex Jennifer L. Boyer transcranial magnetic stimulation (TMS) to deactivate V1, producing transient blindness for visual targets choice discrimination tasks for orien- tation (experiment 1) and color (experiment 2) were both signifi

  11. Imprecise Whisker Map in the Neonatal Rat Barrel Cortex.

    PubMed

    Mitrukhina, Olga; Suchkov, Dmitry; Khazipov, Roustem; Minlebaev, Marat

    2015-10-01

    The somatosensory barrel cortex in rodents contains a topographic map of the facial whiskers where each cortical barrel is tuned to a corresponding whisker. However, exactly when this correspondence is established during development and how precise the functional topography of the whisker protomap is at birth, before the anatomical formation of barrels, are questions that remain unresolved. Here, using extracellular and whole-cell recordings from the barrel cortex of 0- to 7-day-old (P0-7; P0 = day of birth) rat pups in vivo, we report a low level of tuning to the principal whisker at P0-1, with multiple adjacent whiskers evoking large multi- and single-unit responses and excitatory postsynaptic currents in cortical neurons. Additionally, we found broad and largely overlapping projection fields (PFs) for neighboring whiskers in the barrel cortex at P0-1. Starting from P2-3, a segregated whisker map emerged, characterized by preferential single whisker tuning and segregated whisker PFs. These results indicate that the functional whisker protomap in the somatosensory cortex is imprecise at birth, that for 2-3 days after birth, whiskers compete for the cortical target territories, and that formation of a segregated functional whisker map coincides with emergence of the anatomical barrel map. PMID:25100857

  12. INTRODUCTION During embryogenesis, neurons of the cerebral cortex are

    E-print Network

    McConnell, Susan

    that cells follow both radial and nonradial pathways as they travel from their sites of origin that nonradial migration is equally common in brain slices and the intact cortex and that it increases during neurogenesis. Additionally, cells appear to follow nonradial trajectories at all levels of the developing

  13. Preference for Audiovisual Speech Congruency in Superior Temporal Cortex.

    PubMed

    Lüttke, Claudia S; Ekman, Matthias; van Gerven, Marcel A J; de Lange, Floris P

    2016-01-01

    Auditory speech perception can be altered by concurrent visual information. The superior temporal cortex is an important combining site for this integration process. This area was previously found to be sensitive to audiovisual congruency. However, the direction of this congruency effect (i.e., stronger or weaker activity for congruent compared to incongruent stimulation) has been more equivocal. Here, we used fMRI to look at the neural responses of human participants during the McGurk illusion-in which auditory /aba/ and visual /aga/ inputs are fused to perceived /ada/-in a large homogenous sample of participants who consistently experienced this illusion. This enabled us to compare the neuronal responses during congruent audiovisual stimulation with incongruent audiovisual stimulation leading to the McGurk illusion while avoiding the possible confounding factor of sensory surprise that can occur when McGurk stimuli are only occasionally perceived. We found larger activity for congruent audiovisual stimuli than for incongruent (McGurk) stimuli in bilateral superior temporal cortex, extending into the primary auditory cortex. This finding suggests that superior temporal cortex prefers when auditory and visual input support the same representation. PMID:26351991

  14. 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…

  15. 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…

  16. Orbito-Frontal Cortex Is Necessary for Temporal Context Memory

    ERIC Educational Resources Information Center

    Duarte, Audrey; Henson, Richard N.; Knight, Robert T.; Emery, Tina; Graham, Kim S.

    2010-01-01

    Lesion and neuroimaging studies suggest that orbito-frontal cortex (OFC) supports temporal aspects of episodic memory. However, it is unclear whether OFC contributes to the encoding and/or retrieval of temporal context and whether it is selective for temporal relative to nontemporal (spatial) context memory. We addressed this issue with two…

  17. Prior expectations bias sensory representations in visual cortex.

    PubMed

    Kok, Peter; Brouwer, Gijs Joost; van Gerven, Marcel A J; de Lange, Floris P

    2013-10-01

    Perception is strongly influenced by expectations. Accordingly, perception has sometimes been cast as a process of inference, whereby sensory inputs are combined with prior knowledge. However, despite a wealth of behavioral literature supporting an account of perception as probabilistic inference, the neural mechanisms underlying this process remain largely unknown. One important question is whether top-down expectation biases stimulus representations in early sensory cortex, i.e., whether the integration of prior knowledge and bottom-up inputs is already observable at the earliest levels of sensory processing. Alternatively, early sensory processing may be unaffected by top-down expectations, and integration of prior knowledge and bottom-up input may take place in downstream association areas that are proposed to be involved in perceptual decision-making. Here, we implicitly manipulated human subjects' prior expectations about visual motion stimuli, and probed the effects on both perception and sensory representations in visual cortex. To this end, we measured neural activity noninvasively using functional magnetic resonance imaging, and applied a forward modeling approach to reconstruct the motion direction of the perceived stimuli from the signal in visual cortex. Our results show that top-down expectations bias representations in visual cortex, demonstrating that the integration of prior information and sensory input is reflected at the earliest stages of sensory processing. PMID:24107959

  18. Cerebral Cortex doi:10.1093/cercor/bhr360

    E-print Network

    Thompson, Paul

    Cerebral Cortex doi:10.1093/cercor/bhr360 Multimodal MRI Analysis of the Corpus Callosum Reveals degeneration, white matter changes Introduction Huntington's disease (HD) is a severe, dominantly transmitted mutation carries with it a cascade of toxic events that extend beyond the striatum to involve the cerebral

  19. The reorganization of extrastriate cortex in patients with lobectomy.

    PubMed

    Liu, Tina; Nestor, Adrian; Patterson, Christina; Behrmann, Marlene

    2015-09-01

    The recovery of perceptual functions that occur following cortical damage can offer key insights into the nature and plasticity of brain organization. In this respect, studies of individuals post-lobectomy/hemispherectomy offer a unique window into the nature and extent of cortical plasticity. First, in contrast with more common lesions, the extent of the damage in such patients can be extreme (i.e. an entire hemisphere in some cases) yet, at the same time, very well controlled - both cortical and subcortical structures of the remaining hemisphere are typically intact. Second, the extent of the recovery is often disproportionate relative to the extent of the damage - many compromised functions are regained partly or even completely. Using fMRI, our present work characterizes the changes in topography in extrastriate cortex in children who have undergone surgical lobectomy or hemispherectomy of ventral cortex in either hemisphere (compared with control participants who have undergone resections to other areas such as dorsal cortex). We also map language areas in each individual as an anchor for hemispheric dominance. We uncover atypicalities in the selectivity maps to common visual categories (face, object, and word) in the ventral patients and show changes in their development/reorganization over time. Overall, the current results suggest that extensive removal of visual cortex lead to atypical/diminished selectivity for common visual categories despite the absence of major recognition difficulties and that, in some cases, reorganization may result in somewhat more typical selectivity maps. Meeting abstract presented at VSS 2015. PMID:26326122

  20. Extinction Circuits for Fear and Addiction Overlap in Prefrontal Cortex

    ERIC Educational Resources Information Center

    Peters, Jamie; Kalivas, Peter W.; Quirk, Gregory J.

    2009-01-01

    Extinction is a form of inhibitory learning that suppresses a previously conditioned response. Both fear and drug seeking are conditioned responses that can lead to maladaptive behavior when expressed inappropriately, manifesting as anxiety disorders and addiction, respectively. Recent evidence indicates that the medial prefrontal cortex (mPFC) is…

  1. The Role of the Orbitofrontal Cortex in Human Discrimination Learning

    ERIC Educational Resources Information Center

    Chase, Henry W.; Clark, Luke; Myers, Catherine E.; Gluck, Mark A.; Sahakian, Barbara J.; Bullmore, Edward T.; Robbins, Trevor W.

    2008-01-01

    Several lines of evidence implicate the prefrontal cortex in learning but there is little evidence from studies of human lesion patients to demonstrate the critical role of this structure. To this end, we tested patients with lesions of the frontal lobe (n = 36) and healthy controls (n = 35) on two learning tasks: the weather prediction task…

  2. Sparse Representation of Sounds in the Unanesthetized Auditory Cortex

    PubMed Central

    Hromádka, Tomáš; DeWeese, Michael R; Zador, Anthony M

    2008-01-01

    How do neuronal populations in the auditory cortex represent acoustic stimuli? Although sound-evoked neural responses in the anesthetized auditory cortex are mainly transient, recent experiments in the unanesthetized preparation have emphasized subpopulations with other response properties. To quantify the relative contributions of these different subpopulations in the awake preparation, we have estimated the representation of sounds across the neuronal population using a representative ensemble of stimuli. We used cell-attached recording with a glass electrode, a method for which single-unit isolation does not depend on neuronal activity, to quantify the fraction of neurons engaged by acoustic stimuli (tones, frequency modulated sweeps, white-noise bursts, and natural stimuli) in the primary auditory cortex of awake head-fixed rats. We find that the population response is sparse, with stimuli typically eliciting high firing rates (>20 spikes/second) in less than 5% of neurons at any instant. Some neurons had very low spontaneous firing rates (<0.01 spikes/second). At the other extreme, some neurons had driven rates in excess of 50 spikes/second. Interestingly, the overall population response was well described by a lognormal distribution, rather than the exponential distribution that is often reported. Our results represent, to our knowledge, the first quantitative evidence for sparse representations of sounds in the unanesthetized auditory cortex. Our results are compatible with a model in which most neurons are silent much of the time, and in which representations are composed of small dynamic subsets of highly active neurons. PMID:18232737

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

    PubMed

    Hromádka, Tomás; Deweese, Michael R; Zador, Anthony M

    2008-01-01

    How do neuronal populations in the auditory cortex represent acoustic stimuli? Although sound-evoked neural responses in the anesthetized auditory cortex are mainly transient, recent experiments in the unanesthetized preparation have emphasized subpopulations with other response properties. To quantify the relative contributions of these different subpopulations in the awake preparation, we have estimated the representation of sounds across the neuronal population using a representative ensemble of stimuli. We used cell-attached recording with a glass electrode, a method for which single-unit isolation does not depend on neuronal activity, to quantify the fraction of neurons engaged by acoustic stimuli (tones, frequency modulated sweeps, white-noise bursts, and natural stimuli) in the primary auditory cortex of awake head-fixed rats. We find that the population response is sparse, with stimuli typically eliciting high firing rates (>20 spikes/second) in less than 5% of neurons at any instant. Some neurons had very low spontaneous firing rates (<0.01 spikes/second). At the other extreme, some neurons had driven rates in excess of 50 spikes/second. Interestingly, the overall population response was well described by a lognormal distribution, rather than the exponential distribution that is often reported. Our results represent, to our knowledge, the first quantitative evidence for sparse representations of sounds in the unanesthetized auditory cortex. Our results are compatible with a model in which most neurons are silent much of the time, and in which representations are composed of small dynamic subsets of highly active neurons. PMID:18232737

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

    E-print Network

    Wellman, Cara

    occur in response to chronic stress, we assessed the effects of daily restraint stress on dendritic morphol- ogy in medial prefrontal cortex. Male rats were exposed to either 3 h of restraint stress daily for 3 weeks or left unhandled except for weighing during this period. On the last day of restraint

  5. PREFRONTAL CORTICAL MODULATION OF ACETYLCHOLINE RELEASE IN POSTERIOR PARIETAL CORTEX

    E-print Network

    Bruno, John P.

    (PPC). Cortical cholinergic inputs, originating from the basal forebrain cholinergic sys- tem, have. © 2005 Published by Elsevier Ltd on behalf of IBRO. Key words: attention, basal forebrain, cortex). Studies using laboratory animals revealed the importance of the basal forebrain cortical cholinergic

  6. Cerebral Cortex doi:10.1093/cercor/bhm256

    E-print Network

    Wandell, Brian A.

    Cerebral Cortex doi:10.1093/cercor/bhm256 V1 Projection Zone Signals in Human Macular Degeneration abnormal cortical signals in humans with juvenile macular degeneration (JMD). These signals have beenMRI) in a subject with age-related macular degeneration, Sunness et al. (2004) report no significant responses

  7. 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…

  8. 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…

  9. RESEARCH REPORTS Medial Orbitofrontal Cortex Gray Matter Is Reduced in

    E-print Network

    Banich, Marie T.

    in orbitofrontal cortex (OFC) and associated limbic- prefrontal pathways that might underlie abuse-related behavior. High-resolution T1-weighted images were acquired on a 3-T magnetic resonance system. Image processing as a patho- logical usurpation of the cortico­striatal­limbic circuit me- diating reward behavior (1­4). Long

  10. Cerebral Cortex doi:10.1093/cercor/bhm231

    E-print Network

    Cerebral Cortex doi:10.1093/cercor/bhm231 Remediation of Sleep-Deprivation-- Induced Working Memory to test the role of selected cortical regions in remediating sleep- deprivation--induced deficits resonance imaging (fMRI)--identified network associated with sleep-deprivation--induced WM performance

  11. Multiarea visuotopic map complexes in macaque striate and extrastriate cortex

    E-print Network

    Schwartz, Eric L.

    Multi­area visuotopic map complexes in macaque striate and extra­striate cortex J.R. Polimeni a , M to the full­field, two­dimensional topographic structure of macaque V1, V2, and V3. A single map function and a publicly available data set of full­field macaque V1 and V2 topography. Good quantitative agreement

  12. A Mediating Role of the Premotor Cortex in Phoneme Segmentation

    ERIC Educational Resources Information Center

    Sato, Marc; Tremblay, Pascale; Gracco, Vincent L.

    2009-01-01

    Consistent with a functional role of the motor system in speech perception, disturbing the activity of the left ventral premotor cortex by means of repetitive transcranial magnetic stimulation (rTMS) has been shown to impair auditory identification of syllables that were masked with white noise. However, whether this region is crucial for speech…

  13. Off-center yaw rotation: effect of naso-occipital linear acceleration on the nystagmus response of normal human subjects and patients after unilateral vestibular loss.

    PubMed

    Curthoys, I S; Haslwanter, T; Black, R A; Burgess, A M; Halmagyi, G M; Topple, A N; Todd, M J

    1998-12-01

    Dual search coils were used to record horizontal, vertical and torsional eye movement components of one eye during nystagmus caused by off-center yaw rotation (yaw centrifugation). Both normal healthy human subjects (n=7) and patients with only one functioning labyrinth (n=12) were studied in order to clarify how the concomitant linear acceleration affected the nystagmus response. Each subject was seated with head erect on the arm of a fixed-chair human centrifuge, 1 m away from the center of the rotation, and positioned to be facing along a radius; either towards (facing-in) or away from (facing-out) the center of rotation. Both yaw right and yaw left angular accelerations of 10 degrees s(-2) from 0 to 200 degrees/s were studied. During rotation a centripetal linear acceleration (increasing from 0 to 1.24xg units) was directed along the subject's naso-occipital axis resulting in a shift of the resultant angle of the gravitoinertial acceleration (GIA) of 51 degrees in the subject's pitch plane and an increase in the total GIA magnitude from 1.0 to 1.59xg. In normal subjects during the angular acceleration off-center there were, in addition to the horizontal eye velocity components, torsional and vertical eye velocities present. The magnitude of these additional components, although small, was larger than observed during similar experiments with on-center angular acceleration (Haslwanter et al. 1996), and the change in these components is attributed to the additional effect of the linear acceleration stimulation. In the pitch plane the average size of the shift of the axis of eye velocity (AEV) during the acceleration was about 8 degrees for a 51 degrees shift of the GIA (around 16% of the GIA shift) so that the AEV-GIA alignment was inadequate. There was a very marked difference in the size of the AEV shift depending on whether the person was facing-in [AEV shift forward (i.e. non-compensatory) of about 4 degrees] or facing-out [AEV shift forward (i.e. compensatory) of around 12 degrees]. The linear acceleration decreased the time constant of decay of the horizontal component of the post-rotatory nystagmus: from an average of 24.8 degrees/s facing-in to an average of 11.3 degrees/s facing-out. The linear acceleration dumps torsional eye velocity in an manner analogous to, but independent of, the dumping of horizontal eye velocity. Patients with UVD had dramatically reduced torsional eye velocities for both facing-in and facing-out headings, and there was little if any shift of the AEV in UVD patients. The relatively small effects of linear acceleration on human canal-induced nystagmus found here confirms other recent studies in humans (Fetter et al. 1996) in contrast to evidence from monkeys and emphasizes the large and important differences between humans and monkeys in otolith-canal interaction. Our results confirm the vestibular control of the axis of eye velocity of humans is essentially head-referenced whereas in monkeys that control is essentially space-referenced. PMID:9870602

  14. 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

  15. Faces are represented holistically in the human occipito-temporal cortex

    E-print Network

    Rossion, Bruno

    in the extraction of individual face representations (Gauthier et al., 2000; Rossion et al., 2003; Grill-Spector et on terminology: FFA = MFG (middle fusiform gyrus) OFA = IOG (inferior occipital gyrus) · The two functional regions are defined by a comparison of faces and nonface stimuli · Either MFG/IOG terminology is used here

  16. 04/25/2007 01:56 PMUPS: Tracking Information Page 1 of 2http://wwwapps.ups.com/WebTracking/printSummary?loc=en_US&page=...el=1&addr=1&shipOn=1&service=1&weight=1&payment=0&displayFlag=1

    E-print Network

    Bartholdi III, John J.

    04/25/2007 01:56 PMUPS: Tracking Information Page 1 of 2http://wwwapps.ups.com Information Page 2 of 2http://wwwapps.ups.com/WebTracking/printSummary?loc=en_US&page=...el=1&addr=1&shipOn=1.M. BILLING INFORMATION RECEIVED Tracking results provided by UPS: 04/25/2007 1:55 P.M. EST (USA) NOTICE: UPS

  17. Anterior Cingulate Cortex and Cognitive Control: Neuropsychological and Electrophysiological Findings in Two Patients with Lesions to Dorsomedial Prefrontal Cortex

    ERIC Educational Resources Information Center

    Lovstad, M.; Funderud, I.; Meling, T.; Kramer, U. M.; Voytek, B.; Due-Tonnessen, P.; Endestad, T.; Lindgren, M.; Knight, R. T.; Solbakk, A. K.

    2012-01-01

    Whereas neuroimaging studies of healthy subjects have demonstrated an association between the anterior cingulate cortex (ACC) and cognitive control functions, including response monitoring and error detection, lesion studies are sparse and have produced mixed results. Due to largely normal behavioral test results in two patients with medial…

  18. Studies of the earliest generated cells of the cat's visual cortex: cogeneration of subplate and marginal zones.

    PubMed

    Luskin, M B; Shatz, C J

    1985-04-01

    The earliest generated cells of the cat's telencephalon that may play a role in the formation of the primary visual cortex are the subject of this study. Using [3H]thymidine autoradiography, we have found that these cells are generated between embryonic day 24 (E24) and E30 (gestation is 65 days) and that they are present in very low numbers in the white matter of the adult brain. These cells are rarely labeled by injections made after E30, when the cells destined for the cortical layers are generated. Examination of the labeling pattern in the fetal brain 10 days or more after administration of [3H]thymidine between E24 and E30 revealed a bistratified distribution of these early generated cells. Labeled cells were found in large numbers in two embryonic zones flanking the developing cortical plate: above in the marginal zone and below in the subplate. (Some if not all of the marginal zone cells constitute the population of Cajal-Retzius cells of the cat's telencephalon.). These experiments indicate that cells of the subplate and marginal zones are cogenerated in time during the days just preceding the genesis of the cortical plate. We also examined the distribution of the early generated cells shortly after their genesis--on E30, a time when cells of the cortical plate are just being generated at the ventricular zone. In this case, the labeling pattern at the occipital pole was not bistratified. Rather, labeled cells were situated within a single zone extending from the pial surface inward to the border of the ventricular zone. This finding indicates that the cells of the subplate and marginal zones are generated as a contiguous population that is subsequently split apart by the insertion of cells forming the cortical plate. A comparison between the number of early generated cells found in fetal and newborn brains with that found in adult brains suggests that these cells are generated initially in substantial numbers but then largely disappear during early postnatal life, since injections of [3H]thymidine between E24 and E30 yielded large numbers of labeled cells in the white matter and layer 1 at birth, but very few at 2 months postnatal. This significant loss contrasted with the results from injections made just a few days later (E33) that resulted in large numbers of labeled cells in cortical layer 6 not only at birth but also in adulthood.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:3981242

  19. Efficacy of Cathodal Transcranial Direct Current Stimulation Over the Left Orbitofrontal Cortex in a Patient With Treatment-Resistant Obsessive-Compulsive Disorder.

    PubMed

    Mondino, Marine; Haesebaert, Frédéric; Poulet, Emmanuel; Saoud, Mohamed; Brunelin, Jérôme

    2015-12-01

    Obsessive-compulsive disorder (OCD) is a disabling and frequent neuropsychiatric disorder. Forty percent to 60% of patients with OCD fail to respond to available treatments. Neuroimaging studies have highlighted an association between the severity of obsessive and compulsive symptoms and an increased activity of the left orbitofrontal cortex (OFC) in patients with OCD. Transcranial direct current stimulation (tDCS) is a powerful and easy-to-use tool to modulate brain activity. Cathodal tDCS (c-tDCS) is assumed to decrease cortical excitability in the targeted brain region. We hypothesized that c-tDCS applied over the left OFC alleviates symptoms in patients with treatment-resistant OCD. We report here the case of a patient who received 10 sessions (2 mA, 20 minutes) of c-tDCS. The tDCS sessions were delivered twice a day with a 2-hour interval, with the cathode (35 cm) placed over the left OFC and the anode (100 cm) placed over the contralateral occipital region. No adverse event was reported. One month after the completion of the tDCS sessions, we observed a 26% reduction in severity of obsessive and compulsive symptoms measured using the Yale-Brown Obsessive Compulsive Scale scores. These findings are consistent with a previous study reporting a similar reduction in obsessive and compulsive symptoms after a low-frequency repetitive transcranial magnetic stimulation was given to the left OFC. Our results indicate that c-tDCS applied over the left OFC may be a suitable and safe treatment in patients with treatment-resistant OCD. PMID:25651393

  20. Somatostatin binding to dissociated cells from rat cerebral cortex

    SciTech Connect

    Colas, B.; Prieto, J.C.; Arilla, E. )

    1990-11-01

    A method has been developed for the study of somatostatin (SS) binding to dissociated cells from rat cerebral cortex. Binding of {sup 125}I (Tyr11)SS to cells obtained by mechanical dissociation of rat cerebral cortex was dependent on time and temperature, saturable, reversible and highly specific. Under conditions of equilibrium, i.e., 60 min at 25 degrees C, native SS inhibited tracer binding in a dose-dependent manner. The Scatchard analysis of binding data was linear and yielded a dissociation constant of 0.60 +/- 0.08 nM with a maximal binding capacity of 160 +/- 16 fmol/mg protein. The binding of {sup 125}I (Tyr11)SS was specific as shown in experiments on tracer displacement by the native peptides, SS analogues, and unrelated peptides.

  1. A Specialized Odor Memory Buffer in Primary Olfactory Cortex

    PubMed Central

    Zelano, Christina; Montag, Jessica; Khan, Rehan; Sobel, Noam

    2009-01-01

    Background The neural substrates of olfactory working memory are unknown. We addressed the questions of whether olfactory working memory involves a verbal representation of the odor, or a sensory image of the odor, or both, and the location of the neural substrates of these processes. Methodology/Principal Findings We used functional magnetic resonance imaging to measure activity in the brains of subjects who were remembering either nameable or unnameable odorants. We found a double dissociation whereby remembering nameable odorants was reflected in sustained activity in prefrontal language areas, and remembering unnameable odorants was reflected in sustained activity in primary olfactory cortex. Conclusions/Significance These findings suggest a novel dedicated mechanism in primary olfactory cortex, where odor information is maintained in temporary storage to subserve ongoing tasks. PMID:19305509

  2. Spontaneous origin of topological complexity in the cerebral cortex

    SciTech Connect

    Chapline, G.

    1995-04-07

    Attention is drawn to the possibility of regarding the cerebral cortex as a physical system whose only excitations are topological. An attractive feature of such a hypothesis is that it is possible to understand how local dynamics could spontaneously give rise to a large scale organization of neurons and synapses that one might associate with sophisticated cognitive capabilities. It is suggested that the spontaneous appearance of topological disorder in the topological phases of 2-D and 4-D quantum gravity illustrates how the topological complexity of the human brain can develop. In particular the cooperative behavior of different neural circuits in the cerebral cortex may be closely related to the topology of certain 4-manifolds.

  3. The Roles of Occipitotemporal Cortex in Reading, Spelling, and Naming

    PubMed Central

    Sebastian, Rajani; Gomez, Yessenia; Leigh, Richard; Davis, Cameron; Newhart, Melissa; Hillis, Argye E.

    2014-01-01

    We evaluated the hypothesis that Brodmann’s area 37 within left occipitotemporal cortex has at least two important functions in lexical processing. One role is the computation of case-, font-, location-, and orientation-independent grapheme descriptions for written word recognition and production (reading and spelling). This role may depend on the medial part of BA 37, in left midfusiform gyrus. The second role is in accessing modality-independent lexical representations for output, for naming and for reading and spelling of irregular or exception words. This role may depend on the lateral part of BA 37 in inferior temporal cortex. We tested these hypotheses in 234 participants with acute left hemisphere ischemic stroke who underwent MRI and language testing within 48 hours of onset of stroke symptoms. PMID:24527769

  4. Reconstitution of an Actin Cortex Inside a Liposome

    PubMed Central

    Pontani, Léa-Laetitia; van der Gucht, Jasper; Salbreux, Guillaume; Heuvingh, Julien; Joanny, Jean-François; Sykes, Cécile

    2009-01-01

    Abstract The composite and versatile structure of the cytoskeleton confers complex mechanical properties on cells. Actin filaments sustain the cell membrane and their dynamics insure cell shape changes. For example, the lamellipodium moves by actin polymerization, a mechanism that has been studied using simplified experimental systems. Much less is known about the actin cortex, a shell-like structure underneath the membrane that contracts for cell movement. We have designed an experimental system that mimicks the cell cortex by allowing actin polymerization to nucleate and assemble at the inner membrane of a liposome. Actin shell growth can be triggered inside the liposome, which offers a useful system for a controlled study. The observed actin shell thickness and estimated mesh size of the actin structure are in good agreement with cellular data. Such a system paves the way for a thorough characterization of cortical dynamics and mechanics. PMID:19134475

  5. Neural Anatomy of Primary Visual Cortex Limits Visual Working Memory.

    PubMed

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

    2016-01-01

    Despite the immense processing power of the human brain, working memory storage is severely limited, and the neuroanatomical basis of these limitations has remained elusive. Here, we show that the stable storage limits of visual working memory for over 9 s are bound by the precise gray matter volume of primary visual cortex (V1), defined by fMRI retinotopic mapping. Individuals with a bigger V1 tended to have greater visual working memory storage. This relationship was present independently for both surface size and thickness of V1 but absent in V2, V3 and for non-visual working memory measures. Additional whole-brain analyses confirmed the specificity of the relationship to V1. Our findings indicate that the size of primary visual cortex plays a critical role in limiting what we can hold in mind, acting like a gatekeeper in constraining the richness of working mental function. PMID:25100854

  6. Noninvasive studies of human visual cortex using neuromagnetic techniques

    SciTech Connect

    Aine, C.J.; George, J.S.; Supek, S. ); Maclin, E.L. . Center for Magnetoencephalography)

    1990-01-01

    The major goals of noninvasive studies of the human visual cortex are: to increase knowledge of the functional organization of cortical visual pathways; and to develop noninvasive clinical tests for the assessment of cortical function. Noninvasive techniques suitable for studies of the structure and function of human visual cortex include magnetic resonance imaging (MRI), positron emission tomography (PET), single photon emission tomography (SPECT), scalp recorded event-related potentials (ERPs), and event-related magnetic fields (ERFs). The primary challenge faced by noninvasive functional measures is to optimize the spatial and temporal resolution of the measurement and analytic techniques in order to effectively characterize the spatial and temporal variations in patterns of neuronal activity. In this paper we review the use of neuromagnetic techniques for this purpose. 8 refs., 3 figs.

  7. Tinnitus: the dark side of the auditory cortex plasticity.

    PubMed

    Pantev, Christo; Okamoto, Hidehiko; Teismann, Henning

    2012-04-01

    Music has increasingly been used as a tool for investigation of human cognition and its underlying brain mechanisms. However, music can be used also for neurorehabilitation. Chronic tinnitus is a symptom with high prevalence, especially in industrialized countries. There is evidence that the tinnitus perception is related to unfavorable cortical plastic changes. Maladaptive auditory cortex reorganization may contribute to the generation and maintenance of tinnitus. Because cortical organization can be modified by behavioral training, potentially via reversing maladaptive auditory cortex reorganization, we attempted to reduce tinnitus loudness by exposing chronic tinnitus patients to self-chosen, enjoyable music that was modified ("notched") to contain no energy in the frequency range surrounding the individual tinnitus frequency and thus attracting lateral inhibition to the brain area generating tinnitus. On this basis, we have developed and evaluated a customized music training strategy that appears capable of both reducing cortical tinnitus-related neuronal activity and alleviating subjective tinnitus perception. PMID:22524367

  8. Random positions of dendritic spines in human cerebral cortex.

    PubMed

    Morales, Juan; Benavides-Piccione, Ruth; Dar, Mor; Fernaud, Isabel; Rodríguez, Angel; Anton-Sanchez, Laura; Bielza, Concha; Larrañaga, Pedro; DeFelipe, Javier; Yuste, Rafael

    2014-07-23

    Dendritic spines establish most excitatory synapses in the brain and are located in Purkinje cell's dendrites along helical paths, perhaps maximizing the probability to contact different axons. To test whether spine helixes also occur in neocortex, we reconstructed >500 dendritic segments from adult human cortex obtained from autopsies. With Fourier analysis and spatial statistics, we analyzed spine position along apical and basal dendrites of layer 3 pyramidal neurons from frontal, temporal, and cingulate cortex. Although we occasionally detected helical positioning, for the great majority of dendrites we could not reject the null hypothesis of spatial randomness in spine locations, either in apical or basal dendrites, in neurons of different cortical areas or among spines of different volumes and lengths. We conclude that in adult human neocortex spine positions are mostly random. We discuss the relevance of these results for spine formation and plasticity and their functional impact for cortical circuits. PMID:25057209

  9. Random Positions of Dendritic Spines in Human Cerebral Cortex

    PubMed Central

    Morales, Juan; Benavides-Piccione, Ruth; Dar, Mor; Fernaud, Isabel; Rodríguez, Angel; Anton-Sanchez, Laura; Bielza, Concha; Larrañaga, Pedro; DeFelipe, Javier

    2014-01-01

    Dendritic spines establish most excitatory synapses in the brain and are located in Purkinje cell's dendrites along helical paths, perhaps maximizing the probability to contact different axons. To test whether spine helixes also occur in neocortex, we reconstructed >500 dendritic segments from adult human cortex obtained from autopsies. With Fourier analysis and spatial statistics, we analyzed spine position along apical and basal dendrites of layer 3 pyramidal neurons from frontal, temporal, and cingulate cortex. Although we occasionally detected helical positioning, for the great majority of dendrites we could not reject the null hypothesis of spatial randomness in spine locations, either in apical or basal dendrites, in neurons of different cortical areas or among spines of different volumes and lengths. We conclude that in adult human neocortex spine positions are mostly random. We discuss the relevance of these results for spine formation and plasticity and their functional impact for cortical circuits. PMID:25057209

  10. Nonsensory target-dependent organization of piriform cortex.

    PubMed

    Chen, Chien-Fu F; Zou, Dong-Jing; Altomare, Clara G; Xu, Lu; Greer, Charles A; Firestein, Stuart J

    2014-11-25

    The piriform cortex (PCX) is the largest component of the olfactory cortex and is hypothesized to be the locus of odor object formation. The distributed odorant representation found in PCX contrasts sharply with the topographical representation seen in other primary sensory cortices, making it difficult to test this view. Recent work in PCX has focused on functional characteristics of these distributed afferent and association fiber systems. However, information regarding the efferent projections of PCX and how those may be involved in odor representation and object recognition has been largely ignored. To investigate this aspect of PCX, we have used the efferent pathway from mouse PCX to the orbitofrontal cortex (OFC). Using double fluorescent retrograde tracing, we identified the output neurons (OPNs) of the PCX that project to two subdivisions of the OFC, the agranular insula and the lateral orbitofrontal cortex (AI-OPNs and LO-OPNs, respectively). We found that both AI-OPNs and LO-OPNs showed a distinct spatial topography within the PCX and fewer than 10% projected to both the AI and the LO as judged by double-labeling. These data revealed that the efferent component of the PCX may be topographically organized. Further, these data suggest a model for functional organization of the PCX in which the OPNs are grouped into parallel output circuits that provide olfactory information to different higher centers. The distributed afferent input from the olfactory bulb and the local PCX association circuits would then ensure a complete olfactory representation, pattern recognition capability, and neuroplasticity in each efferent circuit. PMID:25385630

  11. Sensory uncertainty decoded from visual cortex predicts behavior

    PubMed Central

    van Bergen, Ruben S; Ma, Wei Ji; Pratte, Michael S; Jehee, Janneke F M

    2015-01-01

    Bayesian theories of neural coding propose that sensory uncertainty is represented by a probability distribution encoded in neural population activity, but direct neural evidence supporting this hypothesis is currently lacking. Using fMRI in combination with a generative model-based analysis, we found that probability distributions reflecting sensory uncertainty could reliably be estimated from human visual cortex and, moreover, that observers appeared to use knowledge of this uncertainty in their perceptual decisions. PMID:26502262

  12. The Tracking of Speech Envelope in the Human Cortex

    PubMed Central

    Kubanek, Jan; Brunner, Peter; Gunduz, Aysegul; Poeppel, David; Schalk, Gerwin

    2013-01-01

    Humans are highly adept at processing speech. Recently, it has been shown that slow temporal information in speech (i.e., the envelope of speech) is critical for speech comprehension. Furthermore, it has been found that evoked electric potentials in human cortex are correlated with the speech envelope. However, it has been unclear whether this essential linguistic feature is encoded differentially in specific regions, or whether it is represented throughout the auditory system. To answer this question, we recorded neural data with high temporal resolution directly from the cortex while human subjects listened to a spoken story. We found that the gamma activity in human auditory cortex robustly tracks the speech envelope. The effect is so marked that it is observed during a single presentation of the spoken story to each subject. The effect is stronger in regions situated relatively early in the auditory pathway (belt areas) compared to other regions involved in speech processing, including the superior temporal gyrus (STG) and the posterior inferior frontal gyrus (Broca's region). To further distinguish whether speech envelope is encoded in the auditory system as a phonological (speech-related), or instead as a more general acoustic feature, we also probed the auditory system with a melodic stimulus. We found that belt areas track melody envelope weakly, and as the only region considered. Together, our data provide the first direct electrophysiological evidence that the envelope of speech is robustly tracked in non-primary auditory cortex (belt areas in particular), and suggest that the considered higher-order regions (STG and Broca's region) partake in a more abstract linguistic analysis. PMID:23408924

  13. Sensory stimulation shifts visual cortex from synchronous to asynchronous states

    PubMed Central

    Tan, Andrew Y.Y.; Chen, Yuzhi; Scholl, Benjamin; Seidemann, Eyal; Priebe, Nicholas J.

    2014-01-01

    In the mammalian cerebral cortex, neural responses are highly variable during spontaneous activity and sensory stimulation. To explain this variability, the cortex of alert animals has been hypothesized to be in an asynchronous high conductance state in which irregular spiking arises from the convergence of large numbers of uncorrelated excitatory and inhibitory inputs onto individual neurons1–4. Signatures of this state are that a neuron’s membrane potential (Vm) hovers just below spike threshold, and its aggregate synaptic input is nearly Gaussian, arising from many uncorrelated inputs1–4. Alternatively, irregular spiking could arise from infrequent correlated input events that elicit large Vm fluctuations5,6. To distinguish these hypotheses, we developed a technique to carry out whole-cell Vm measurements from the cortex of behaving monkeys, focusing on primary visual cortex (V1) of monkeys performing a visual fixation task. Contrary to the predictions of an asynchronous state, mean Vm during fixation was far from threshold (14 mV) and spiking was triggered by occasional large spontaneous fluctuations. Distributions of Vm values were skewed beyond that expected for a range of Gaussian input6,7, but were consistent with synaptic input arising from infrequent correlated events5,6. Furthermore, spontaneous Vm fluctuations were correlated with the surrounding network activity, as reflected in simultaneously recorded nearby local field potential (LFP). Visual stimulation, however, led to responses more consistent with an asynchronous state: mean Vm approached threshold, fluctuations became more Gaussian, and correlations between single neurons and the surrounding network were disrupted. These observations demonstrate that sensory drive can shift a common cortical circuitry from a synchronous to an asynchronous state. PMID:24695217

  14. Nonsensory target-dependent organization of piriform cortex

    PubMed Central

    Chen, Chien-Fu F.; Zou, Dong-Jing; Altomare, Clara G.; Xu, Lu; Greer, Charles A.; Firestein, Stuart J.

    2014-01-01

    The piriform cortex (PCX) is the largest component of the olfactory cortex and is hypothesized to be the locus of odor object formation. The distributed odorant representation found in PCX contrasts sharply with the topographical representation seen in other primary sensory cortices, making it difficult to test this view. Recent work in PCX has focused on functional characteristics of these distributed afferent and association fiber systems. However, information regarding the efferent projections of PCX and how those may be involved in odor representation and object recognition has been largely ignored. To investigate this aspect of PCX, we have used the efferent pathway from mouse PCX to the orbitofrontal cortex (OFC). Using double fluorescent retrograde tracing, we identified the output neurons (OPNs) of the PCX that project to two subdivisions of the OFC, the agranular insula and the lateral orbitofrontal cortex (AI-OPNs and LO-OPNs, respectively). We found that both AI-OPNs and LO-OPNs showed a distinct spatial topography within the PCX and fewer than 10% projected to both the AI and the LO as judged by double-labeling. These data revealed that the efferent component of the PCX may be topographically organized. Further, these data suggest a model for functional organization of the PCX in which the OPNs are grouped into parallel output circuits that provide olfactory information to different higher centers. The distributed afferent input from the olfactory bulb and the local PCX association circuits would then ensure a complete olfactory representation, pattern recognition capability, and neuroplasticity in each efferent circuit. PMID:25385630

  15. Distinct development of the cerebral cortex in platypus and echidna.

    PubMed

    Ashwell, Ken W S; Hardman, Craig D

    2012-01-01

    Both lineages of the modern monotremes have distinctive features in the cerebral cortex, but the developmental mechanisms that produce such different adult cortical architecture remain unknown. Similarly, nothing is known about the differences and/or similarities between monotreme and therian cortical development. We have used material from the Hill embryological collection to try to answer key questions concerning cortical development in monotremes. Our findings indicate that gyrencephaly begins to emerge in the echidna brain shortly before birth (crown-rump length 12.5 mm), whereas the cortex of the platypus remains lissencephalic throughout development. The cortices of both monotremes are very immature at the time of hatching, much like that seen in marsupials, and both have a subventricular zone (SubV) within both the striatum and pallium during post-hatching development. It is particularly striking that in the platypus, this region has an extension from the palliostriatal angle beneath the developing trigeminoreceptive part of the somatosensory cortex of the lateral cortex. The putative SubV beneath the trigeminal part of S1 appears to accommodate at least two distinct types of cell and many mitotic figures and (particularly in the platypus) appears to be traversed by large numbers of thalamocortical axons as these grow in. The association with putative thalamocortical fibres suggests that this region may also serve functions similar to the subplate zone of Eutheria. These findings suggest that cortical development in each monotreme follows distinct paths from at least the time of birth, consistent with a long period of independent and divergent cortical evolution. PMID:22143038

  16. Decoding bipedal locomotion from the rat sensorimotor cortex

    NASA Astrophysics Data System (ADS)

    Rigosa, J.; Panarese, A.; Dominici, N.; Friedli, L.; van den Brand, R.; Carpaneto, J.; DiGiovanna, J.; Courtine, G.; Micera, S.

    2015-10-01

    Objective. Decoding forelimb movements from the firing activity of cortical neurons has been interfaced with robotic and prosthetic systems to replace lost upper limb functions in humans. Despite the potential of this approach to improve locomotion and facilitate gait rehabilitation, decoding lower limb movement from the motor cortex has received comparatively little attention. Here, we performed experiments to identify the type and amount of information that can be decoded from neuronal ensemble activity in the hindlimb area of the rat motor cortex during bipedal locomotor tasks. Approach. Rats were trained to stand, step on a treadmill, walk overground and climb staircases in a bipedal posture. To impose this gait, the rats were secured in a robotic interface that provided support against the direction of gravity and in the mediolateral direction, but behaved transparently in the forward direction. After completion of training, rats were chronically implanted with a micro-wire array spanning the left hindlimb motor cortex to record single and multi-unit activity, and bipolar electrodes into 10 muscles of the right hindlimb to monitor electromyographic signals. Whole-body kinematics, muscle activity, and neural signals were simultaneously recorded during execution of the trained tasks over multiple days of testing. Hindlimb kinematics, muscle activity, gait phases, and locomotor tasks were decoded using offline classification algorithms. Main results. We found that the stance and swing phases of gait and the locomotor tasks were detected with accuracies as robust as 90% in all rats. Decoded hindlimb kinematics and muscle activity exhibited a larger variability across rats and tasks. Significance. Our study shows that the rodent motor cortex contains useful information for lower limb neuroprosthetic development. However, brain-machine interfaces estimating gait phases or locomotor behaviors, instead of continuous variables such as limb joint positions or speeds, are likely to provide more robust control strategies for the design of such neuroprostheses.

  17. Multimodal Lexical Processing in Auditory Cortex Is Literacy Skill Dependent

    PubMed Central

    McNorgan, Chris; Awati, Neha; Desroches, Amy S.; Booth, James R.

    2014-01-01

    Literacy is a uniquely human cross-modal cognitive process wherein visual orthographic representations become associated with auditory phonological representations through experience. Developmental studies provide insight into how experience-dependent changes in brain organization influence phonological processing as a function of literacy. Previous investigations show a synchrony-dependent influence of letter presentation on individual phoneme processing in superior temporal sulcus; others demonstrate recruitment of primary and associative auditory cortex during cross-modal processing. We sought to determine whether brain regions supporting phonological processing of larger lexical units (monosyllabic words) over larger time windows is sensitive to cross-modal information, and whether such effects are literacy dependent. Twenty-two children (age 8–14 years) made rhyming judgments for sequentially presented word and pseudoword pairs presented either unimodally (auditory- or visual-only) or cross-modally (audiovisual). Regression analyses examined the relationship between literacy and congruency effects (overlapping orthography and phonology vs. overlapping phonology-only). We extend previous findings by showing that higher literacy is correlated with greater congruency effects in auditory cortex (i.e., planum temporale) only for cross-modal processing. These skill effects were specific to known words and occurred over a large time window, suggesting that multimodal integration in posterior auditory cortex is critical for fluent reading. PMID:23588185

  18. Engagement of right temporal cortex during processing of linguistic context.

    PubMed

    Kircher, T T; Brammer, M; Tous Andreu, N; Williams, S C; McGuire, P K

    2001-01-01

    Language processing involves the interplay of areas in both cerebral hemispheres. Whereas the left temporal lobe is necessary for most language tasks, the right hemisphere seems to be additionally activated during processing of paragraphs and metaphors. We studied the neural correlates of word generation and selection in a sentence context, using functional magnetic resonance imaging (fMRI). Cerebral activation was measured while seven healthy, right handed volunteers read and completed sentence stems, with relatively low Cloze frequency, out loud. During a GENERATION condition, subjects were required to generate a word which completed a sentence stem appropriately. During a DECISION condition, subjects selected and articulated one of two presented terminal words. A READING condition in which subjects read an appropriate completion aloud, served as baseline. When GENERATION was compared to READING or DECISION, the left middle frontal, anterior cingulate, precuneus and right lateral temporal cortex were activated. During DECISION relative to READING, the left inferior frontal and middle/superior temporal cortex bilaterally were activated. The prominent engagement of the right lateral temporal cortex during the GENERATION conditions may reflect the processing of linguistic context, and particularly the activation of multiple meanings in the course of producing an appropriate completion. PMID:11369403

  19. Specialized Cortex Glial Cells Accumulate Lipid Droplets in Drosophila melanogaster

    PubMed Central

    Kis, Viktor; Barti, Benjámin; Lippai, Mónika; Sass, Miklós

    2015-01-01

    Lipid droplets (LDs) are common organelles of the majority of eukaryotic cell types. Their biological significance has been extensively studied in mammalian liver cells and white adipose tissue. Although the central nervous system contains the highest relative amount and the largest number of different lipid species, neither the spatial nor the temporal distribution of LDs has been described. In this study, we used the brain of the fruitfly, Drosophila melanogaster, to investigate the neuroanatomy of LDs. We demonstrated that LDs are exclusively localised in glial cells but not in neurons in the larval nervous system. We showed that the brain’s LD pool, rather than being constant, changes dynamically during development and reaches its highest value at the beginning of metamorphosis. LDs are particularly enriched in cortex glial cells located close to the brain surface. These specialized superficial cortex glial cells contain the highest amount of LDs among glial cell types and encapsulate neuroblasts and their daughter cells. Superficial cortex glial cells, combined with subperineurial glial cells, express the Drosophila fatty acid binding protein (Dfabp), as we have demonstrated through light- and electron microscopic immunocytochemistry. To the best of our best knowledge this is the first study that describes LD neuroanatomy in the Drosophila larval brain. PMID:26148013

  20. Representation of temporal sound features in the human auditory cortex.

    PubMed

    Nourski, Kirill V; Brugge, John F

    2011-01-01

    Temporal information in acoustic signals is important for the perception of environmental sounds, including speech. This review focuses on several aspects of temporal processing within human auditory cortex and its relevance for the processing of speech sounds. Periodic non-speech sounds, such as trains of acoustic clicks and bursts of amplitude-modulated noise or tones, can elicit different percepts depending on the pulse repetition rate or modulation frequency. Such sounds provide convenient methodological tools to study representation of timing information in the auditory system. At low repetition rates of up to 8-10 Hz, each individual stimulus (a single click or a sinusoidal amplitude modulation cycle) within the sequence is perceived as a separate event. As repetition rates increase up to and above approximately 40 Hz, these events blend together, giving rise first to the percept of flutter and then to pitch. The extent to which neural responses of human auditory cortex encode temporal features of acoustic stimuli is discussed within the context of these perceptual classes of periodic stimuli and their relationship to speech sounds. Evidence for neural coding of temporal information at the level of the core auditory cortex in humans suggests possible physiological counterparts to perceptual categorical boundaries for periodic acoustic stimuli. Temporal coding is less evident in auditory cortical fields beyond the core. Finally, data suggest hemispheric asymmetry in temporal cortical processing. PMID:21476940

  1. Topography and Areal Organization of Mouse Visual Cortex

    PubMed Central

    Garrett, Marina E.; Nauhaus, Ian; Marshel, James H.

    2014-01-01

    To guide future experiments aimed at understanding the mouse visual system, it is essential that we have a solid handle on the global topography of visual cortical areas. Ideally, the method used to measure cortical topography is objective, robust, and simple enough to guide subsequent targeting of visual areas in each subject. We developed an automated method that uses retinotopic maps of mouse visual cortex obtained with intrinsic signal imaging (Schuett et al., 2002; Kalatsky and Stryker, 2003; Marshel et al., 2011) and applies an algorithm to automatically identify cortical regions that satisfy a set of quantifiable criteria for what constitutes a visual area. This approach facilitated detailed parcellation of mouse visual cortex, delineating nine known areas (primary visual cortex, lateromedial area, anterolateral area, rostrolateral area, anteromedial area, posteromedial area, laterointermediate area, posterior area, and postrhinal area), and revealing two additional areas that have not been previously described as visuotopically mapped in mice (laterolateral anterior area and medial area). Using the topographic maps and defined area boundaries from each animal, we characterized several features of map organization, including variability in area position, area size, visual field coverage, and cortical magnification. We demonstrate that higher areas in mice often have representations that are incomplete or biased toward particular regions of visual space, suggestive of specializations for processing specific types of information about the environment. This work provides a comprehensive description of mouse visuotopic organization and describes essential tools for accurate functional localization of visual areas. PMID:25209296

  2. The Insular Taste Cortex Contributes to Odor Quality Coding

    PubMed Central

    Veldhuizen, Maria G.; Nachtigal, Danielle; Teulings, Lynsey; Gitelman, Darren R.; Small, Dana M.

    2010-01-01

    Despite distinct peripheral and central pathways, stimulation of both the olfactory and the gustatory systems may give rise to the sensation of sweetness. Whether there is a common central mechanism producing sweet quality sensations or two discrete mechanisms associated independently with gustatory and olfactory stimuli is currently unknown. Here we used fMRI to determine whether odor sweetness is represented in the piriform olfactory cortex, which is thought to code odor quality, or in the insular taste cortex, which is thought to code taste quality. Fifteen participants sampled two concentrations of a pure sweet taste (sucrose), two sweet food odors (chocolate and strawberry), and two sweet floral odors (lilac and rose). Replicating prior work we found that olfactory stimulation activated the piriform, orbitofrontal and insular cortices. Of these regions, only the insula also responded to sweet taste. More importantly, the magnitude of the response to the food odors, but not to the non-food odors, in this region of insula was positively correlated with odor sweetness rating. These findings demonstrate that insular taste cortex contributes to odor quality coding by representing the taste-like aspects of food odors. Since the effect was specific to the food odors, and only food odors are experienced with taste, we suggest this common central mechanism develops as a function of experiencing flavors. PMID:20700500

  3. Memory's echo: Vivid remembering reactivates sensory-specific cortex

    PubMed Central

    Wheeler, Mark E.; Petersen, Steven E.; Buckner, Randy L.

    2000-01-01

    A fundamental question in human memory is how the brain represents sensory-specific information during the process of retrieval. One hypothesis is that regions of sensory cortex are reactivated during retrieval of sensory-specific information (1). Here we report findings from a study in which subjects learned a set of picture and sound items and were then given a recall test during which they vividly remembered the items while imaged by using event-related functional MRI. Regions of visual and auditory cortex were activated differentially during retrieval of pictures and sounds, respectively. Furthermore, the regions activated during the recall test comprised a subset of those activated during a separate perception task in which subjects actually viewed pictures and heard sounds. Regions activated during the recall test were found to be represented more in late than in early visual and auditory cortex. Therefore, results indicate that retrieval of vivid visual and auditory information can be associated with a reactivation of some of the same sensory regions that were activated during perception of those items. PMID:11005879

  4. Intrahemispheric cortico-cortical connections of the human auditory cortex.

    PubMed

    Cammoun, Leila; Thiran, Jean Philippe; Griffa, Alessandra; Meuli, Reto; Hagmann, Patric; Clarke, Stephanie

    2015-11-01

    The human auditory cortex comprises the supratemporal plane and large parts of the temporal and parietal convexities. We have investigated the relevant intrahemispheric cortico-cortical connections using in vivo DSI tractography combined with landmark-based registration, automatic cortical parcellation and whole-brain structural connection matrices in 20 right-handed male subjects. On the supratemporal plane, the pattern of connectivity was related to the architectonically defined early-stage auditory areas. It revealed a three-tier architecture characterized by a cascade of connections from the primary auditory cortex to six adjacent non-primary areas and from there to the superior temporal gyrus. Graph theory-driven analysis confirmed the cascade-like connectivity pattern and demonstrated a strong degree of segregation and hierarchy within early-stage auditory areas. Putative higher-order areas on the temporal and parietal convexities had more widely spread local connectivity and long-range connections with the prefrontal cortex; analysis of optimal community structure revealed five distinct modules in each hemisphere. The pattern of temporo-parieto-frontal connectivity was partially asymmetrical. In conclusion, the human early-stage auditory cortical connectivity, as revealed by in vivo DSI tractography, has strong similarities with that of non-human primates. The modular architecture and hemispheric asymmetry in higher-order regions is compatible with segregated processing streams and lateralization of cognitive functions. PMID:25173473

  5. Coevolution of radial glial cells and the cerebral cortex.

    PubMed

    De Juan Romero, Camino; Borrell, Víctor

    2015-08-01

    Radial glia cells play fundamental roles in the development of the cerebral cortex, acting both as the primary stem and progenitor cells, as well as the guides for neuronal migration and lamination. These critical functions of radial glia cells in cortical development have been discovered mostly during the last 15 years and, more recently, seminal studies have demonstrated the existence of a remarkable diversity of additional cortical progenitor cell types, including a variety of basal radial glia cells with key roles in cortical expansion and folding, both in ontogeny and phylogeny. In this review, we summarize the main cellular and molecular mechanisms known to be involved in cerebral cortex development in mouse, as the currently preferred animal model, and then compare these with known mechanisms in other vertebrates, both mammal and nonmammal, including human. This allows us to present a global picture of how radial glia cells and the cerebral cortex seem to have coevolved, from reptiles to primates, leading to the remarkable diversity of vertebrate cortical phenotypes. PMID:25808466

  6. Glucose-monitoring neurons in the mediodorsal prefrontal cortex.

    PubMed

    Nagy, Bernadett; Szabó, István; Papp, Szilárd; Takács, Gábor; Szalay, Csaba; Karádi, Zoltán

    2012-03-20

    The mediodorsal prefrontal cortex (mdPFC), a key structure of the limbic neural circuitry, plays important roles in the central regulation of feeding. As an integrant part of the forebrain dopamine (DA) system, it performs complex roles via interconnections with various brain areas where glucose-monitoring (GM) neurons have been identified. The main goal of the present experiments was to examine whether similar GM neurons exist in the mediodorsal prefrontal cortex. To search for such chemosensory cells here, and to estimate their involvement in the DA circuitry, extracellular single neuron activity of the mediodorsal prefrontal cortex of anesthetized Wistar and Sprague-Dawley rats was recorded by means of tungsten wire multibarreled glass microelectrodes during microelectrophoretic administration of d-glucose and DA. One fourth of the neurons tested changed in firing rate in response to glucose, thus, proved to be elements of the forebrain GM neural network. DA responsive neurons in the mdPFC were found to represent similar proportion of all cells; the glucose-excited units were shown to display excitatory whereas the glucose-inhibited neurons were demonstrated to exert mainly inhibitory responses to dopamine. The glucose-monitoring neurons of the mdPFC and their distinct DA sensitivity are suggested to be of particular significance in adaptive processes of the central feeding control. PMID:22330723

  7. Essential functions of primate frontopolar cortex in cognition

    PubMed Central

    Boschin, Erica A.; Piekema, Carinne; Buckley, Mark J.

    2015-01-01

    Brodmann’s area 10 is one of the largest cytoarchitecturally defined regions in the human cerebral cortex, occupying the most anterior part of the prefrontal cortex [frontopolar cortex (FPC)], and is believed to sit atop a prefrontal hierarchy. The crucial contributions that the FPC makes to cognition are unknown. Rodents do not possess such a FPC, but primates do, and we report here the behavioral effects of circumscribed FPC lesions in nonhuman primates. FPC lesions selectively impaired rapid one-trial learning about unfamiliar objects and unfamiliar objects-in-scenes, and also impaired rapid learning about novel abstract rules. Object recognition memory, shifting between established abstract behavioral rules, and the simultaneous application of two distinct rules were unaffected by the FPC lesion. The distinctive pattern of impaired and spared performance across these seven behavioral tasks reveals that the FPC mediates exploration and rapid learning about the relative value of novel behavioral options, and shows that the crucial contributions made by the FPC to cognition differ markedly from the contributions of other primate prefrontal regions. PMID:25691741

  8. Circadian rhythmicity of synapses in mouse somatosensory cortex.

    PubMed

    Jasinska, Malgorzata; Grzegorczyk, Anna; Woznicka, Olga; Jasek, Ewa; Kossut, Malgorzata; Barbacka-Surowiak, Grazyna; Litwin, Jan A; Pyza, Elzbieta

    2015-10-01

    The circadian rhythmicity displayed by motor behavior of mice: activity at night and rest during the day; and the associated changes in the sensory input are reflected by cyclic synaptic plasticity in the whisker representations located in the somatosensory (barrel) cortex. It was not clear whether diurnal rhythmic changes in synapse density previously observed in the barrel cortex resulted from changes in the activity of the animals, from daily light/dark (LD) rhythm or are driven by an endogenous clock. These changes were investigated in the barrel cortex of C57BL/6 mouse strain kept under LD 12 : 12 h conditions and in constant darkness (DD). Stereological analysis of serial electron microscopic sections was used to assess numerical density of synapses. In mice kept under LD conditions, the total density of synapses and the density of excitatory synapses located on dendritic spines was higher during the light period (rest phase). In contrast, the density of inhibitory synapses located on dendritic spines increased during the dark period (activity phase). Under DD conditions, the upregulation of the inhibitory synapses during the activity phase was retained, but the cyclic changes in the density of excitatory synapses were not observed. The results show that the circadian plasticity concerns only synapses located on spines (and not those on dendritic shafts), and that excitatory and inhibitory synapses are differently regulated during the 24 h cycle: the excitatory synapses are influenced by light, whilst the inhibitory synapses are driven by the endogenous circadian clock. PMID:26274013

  9. Integrating information from different senses in the auditory cortex.

    PubMed

    King, Andrew J; Walker, Kerry M M

    2012-12-01

    Multisensory integration was once thought to be the domain of brain areas high in the cortical hierarchy, with early sensory cortical fields devoted to unisensory processing of inputs from their given set of sensory receptors. More recently, a wealth of evidence documenting visual and somatosensory responses in auditory cortex, even as early as the primary fields, has changed this view of cortical processing. These multisensory inputs may serve to enhance responses to sounds that are accompanied by other sensory cues, effectively making them easier to hear, but may also act more selectively to shape the receptive field properties of auditory cortical neurons to the location or identity of these events. We discuss the new, converging evidence that multiplexing of neural signals may play a key role in informatively encoding and integrating signals in auditory cortex across multiple sensory modalities. We highlight some of the many open research questions that exist about the neural mechanisms that give rise to multisensory integration in auditory cortex, which should be addressed in future experimental and theoretical studies. PMID:22798035

  10. Maternal Geophagy of Calabash Chalk on Foetal Cerebral Cortex Histomorphology

    PubMed Central

    EKANEM, Theresa Bassey; EKONG, Moses Bassey; ELUWA, Mokutima Amarachi; IGIRI, Anozeng Oyono; OSIM, Eme Efiom

    2015-01-01

    Background: Calabash chalk, a kaolin-base substance is a common geophagic material mostly consumed by pregnant women. This study investigated its effect on the histomorphology of the foetal cerebral cortex. Methods: Twelve gestating Wistar rats were divided equally into groups 1 and 2. On pregnancy day seven (PD7), group 2 animals were administered 200 mg/kg body weight of calabash chalk suspension, while group 1 animals served as the control and received 1 ml of distilled water, by oral gavages and for 14 days (PD7-PD20). On PD21, the dams were sacrificed, and the foetuses removed, examined for gross malformations, weighed and culled to two foetuses per mother. Their whole brains were excised, weighed and preserved using 10% buffered formalin, and routinely processed by haematoxylin and eosin, and Luxol fast blue methods. Results: The foetuses showed no morphological change, but their mean body weights was higher (p=0.0001). Histomorphological sections of the cerebral cortex showed hypertrophy and hyperplasia of cells in all the cortical layers, with less demonstrated Nissl and higher (p=0.001) cellular population compared with the control group. Conclusion: Calabash chalk cause body weight increase and histomorphological changes in the cerebral cortex of foetuses. PMID:26715904

  11. CREB regulates memory allocation in the insular cortex.

    PubMed

    Sano, Yoshitake; Shobe, Justin L; Zhou, Miou; Huang, Shan; Shuman, Tristan; Cai, Denise J; Golshani, Peyman; Kamata, Masakazu; Silva, Alcino J

    2014-12-01

    The molecular and cellular mechanisms of memory storage have attracted a great deal of attention. By comparison, little is known about memory allocation, the process that determines which specific neurons in a neural network will store a given memory. Previous studies demonstrated that memory allocation is not random in the amygdala; these studies showed that amygdala neurons with higher levels of the cyclic-AMP-response-element-binding protein (CREB) are more likely to be recruited into encoding and storing fear memory. To determine whether specific mechanisms also regulate memory allocation in other brain regions and whether CREB also has a role in this process, we studied insular cortical memory representations for conditioned taste aversion (CTA). In this task, an animal learns to associate a taste (conditioned stimulus [CS]) with the experience of malaise (such as that induced by LiCl; unconditioned stimulus [US]). The insular cortex is required for CTA memory formation and retrieval. CTA learning activates a subpopulation of neurons in this structure, and the insular cortex and the basolateral amygdala (BLA) interact during CTA formation. Here, we used a combination of approaches, including viral vector transfections of insular cortex, arc fluorescence in situ hybridization (FISH), and designer receptors exclusively activated by designer drugs (DREADD) system, to show that CREB levels determine which insular cortical neurons go on to encode a given conditioned taste memory. PMID:25454591

  12. Evolution and development of the mammalian cerebral cortex

    PubMed Central

    Molnár, Zoltán; Kaas, Jon H.; de Carlos, Juan A.; Hevner, Robert F.; Lein, Ed; N?mec, Pavel

    2014-01-01

    Comparative developmental studies of the mammalian brain can identify key changes that can generate the diverse structures and functions of brains. We have studied how the neocortex of early mammals became organized into functionally distinct areas, and how the current level of cortical cellular and laminar specialization arose from the simpler premammalian cortex. We demonstrate the neocortical organization in early mammals that is most informative for an understanding of how the large, complex human brain evolved from a long line of ancestors. The radial and tangential enlargement of the cortex was driven by changes in the patterns of cortical neurogenesis, including alterations in the proportions of distinct progenitor types. Some cortical cell populations travel to the cortex through tangential migration, others migrate radially. A number of recent studies have begun to characterize the chick, mouse, human and non-human primate cortical transcriptome to help us understand how gene expression relates to the development, and to the anatomical and functional organization of the adult neocortex. Although all mammalian forms share the basic layout of cortical areas, the areal proportions and distributions are driven by distinct evolutionary pressures acting on sensory and motor experiences during the individual ontogenies. PMID:24776993

  13. Characterizing synaptic protein development in human visual cortex enables alignment of synaptic age with rat visual cortex

    PubMed Central

    Pinto, Joshua G. A.; Jones, David G.; Williams, C. Kate; Murphy, Kathryn M.

    2015-01-01

    Although many potential neuroplasticity based therapies have been developed in the lab, few have translated into established clinical treatments for human neurologic or neuropsychiatric diseases. Animal models, especially of the visual system, have shaped our understanding of neuroplasticity by characterizing the mechanisms that promote neural changes and defining timing of the sensitive period. The lack of knowledge about development of synaptic plasticity mechanisms in human cortex, and about alignment of synaptic age between animals and humans, has limited translation of neuroplasticity therapies. In this study, we quantified expression of a set of highly conserved pre- and post-synaptic proteins (Synapsin, Synaptophysin, PSD-95, Gephyrin) and found that synaptic development in human primary visual cortex (V1) continues into late childhood. Indeed, this is many years longer than suggested by neuroanatomical studies and points to a prolonged sensitive period for plasticity in human sensory cortex. In addition, during childhood we found waves of inter-individual variability that are different for the four proteins and include a stage during early development (<1 year) when only Gephyrin has high inter-individual variability. We also found that pre- and post-synaptic protein balances develop quickly, suggesting that maturation of certain synaptic functions happens within the 1 year or 2 of life. A multidimensional analysis (principle component analysis) showed that most of the variance was captured by the sum of the four synaptic proteins. We used that sum to compare development of human and rat visual cortex and identified a simple linear equation that provides robust alignment of synaptic age between humans and rats. Alignment of synaptic ages is important for age-appropriate targeting and effective translation of neuroplasticity therapies from the lab to the clinic. PMID:25729353

  14. Observing accidental and intentional unusual actions is associated with different subregions of the medial frontal cortex.

    PubMed

    Desmet, Charlotte; Brass, Marcel

    2015-11-15

    The literature on action observation revealed contradictory results regarding the activation of different subregions of the medial prefrontal cortex when observing unusual behaviour. Error observation research has shown that the posterior part of the medial prefrontal cortex is more active when observing unusual behaviour compared to usual behaviour while action understanding research has revealed some mixed results concerning the role of the anterior part of the medial prefrontal cortex during the observation of unusual actions. Here, we resolve this discrepancy in the literature by showing that different parts of the medial prefrontal cortex are active depending on whether an observed unusual behaviour is intentional or not. While the posterior medial prefrontal cortex is more active when we observe unusual accidental actions compared to unusual intentional actions, a more anterior part of the medial prefrontal cortex is more active when we observe unusual intentional actions compared to unusual accidental actions. PMID:26279209

  15. Fast transmission from the dopaminergic ventral midbrain to the sensory cortex of awake primates.

    PubMed

    Mylius, Judith; Happel, Max F K; Gorkin, Alexander G; Huang, Ying; Scheich, Henning; Brosch, Michael

    2015-11-01

    Motivated by the increasing evidence that auditory cortex is under control of dopaminergic cell structures of the ventral midbrain, we studied how the ventral tegmental area and substantia nigra affect neuronal activity in auditory cortex. We electrically stimulated 567 deep brain sites in total within and in the vicinity of the two dopaminergic ventral midbrain structures and at the same time, recorded local field potentials and neuronal discharges in cortex. In experiments conducted on three awake macaque monkeys, we found that electrical stimulation of the dopaminergic ventral midbrain resulted in short-latency (~35 ms) phasic activations in all cortical layers of auditory cortex. We were also able to demonstrate similar activations in secondary somatosensory cortex and superior temporal polysensory cortex. The electrically evoked responses in these parts of sensory cortex were similar to those previously described for prefrontal cortex. Moreover, these phasic responses could be reversibly altered by the dopamine D1-receptor antagonist SCH23390 for several tens of minutes. Thus, we speculate that the dopaminergic ventral midbrain exerts a temporally precise, phasic influence on sensory cortex using fast-acting non-dopaminergic transmitters and that their effects are modulated by dopamine on a longer timescale. Our findings suggest that some of the information carried by the neuronal discharges in the dopaminergic ventral midbrain, such as the motivational value or the motivational salience, is transmitted to auditory cortex and other parts of sensory cortex. The mesocortical pathway may thus contribute to the representation of non-auditory events in the auditory cortex and to its associative functions. PMID:25084746

  16. Functions of the orbitofrontal and pregenual cingulate cortex in taste, olfaction, appetite and emotion.

    PubMed

    Rolls, E T

    2008-06-01

    Complementary neurophysiological recordings in macaques and functional neuroimaging in humans show that the primary taste cortex in the rostral insula and adjoining frontal operculum provides separate and combined representations of the taste, temperature, and texture (including viscosity and fat texture) of food in the mouth independently of hunger and thus of reward value and pleasantness. One synapse on, in the orbitofrontal cortex, these sensory inputs are for some neurons combined by learning with olfactory and visual inputs. Different neurons respond to different combinations, providing a rich representation of the sensory properties of food. The representation of taste and other food-related stimuli in the orbitofrontal cortex of macaques is found from its lateral border throughout area 13 to within 7 mm of the midline, and in humans the representation of food-related and other pleasant stimuli is found particularly in the medial orbitofrontal cortex. In the orbitofrontal cortex, feeding to satiety with one food decreases the responses of these neurons to that food, but not to other foods, showing that sensory-specific satiety is computed in the primate (including human) orbitofrontal cortex. Consistently, activation of parts of the human orbitofrontal cortex correlates with subjective ratings of the pleasantness of the taste and smell of food. Cognitive factors, such as a word label presented with an odour, influence the pleasantness of the odour, and the activation produced by the odour in the orbitofrontal cortex. Food intake is thus controlled by building a multimodal representation of the sensory properties of food in the orbitofrontal cortex, and gating this representation by satiety signals to produce a representation of the pleasantness or reward value of food which drives food intake. A neuronal representation of taste is also found in the pregenual cingulate cortex, which receives inputs from the orbitofrontal cortex, and in humans many pleasant stimuli activate the pregenual cingulate cortex, pointing towards this as an important area in motivation and emotion. PMID:18642756

  17. Cerebral Cortex September 2008;18:2158--2168 doi:10.1093/cercor/bhm242

    E-print Network

    Sereno, Martin

    sulcus), the intraparietal sulcus, and the vicinity of the frontal eye fields in frontal cortex. Early: biological motion, frontal eye fields, intraparietal sulcus, superior temporal sulcus, topography

  18. Prefrontal Cortex Activity is Reduced in Gambling and Nongambling Substance Users During

    E-print Network

    Banich, Marie T.

    sponsor: Institute for Research on Pathological Gambling and Related Disorders, Harvard Medical School- related reductions in right orbitofrontal and dorsolateral prefrontal cortex in abstinent marijuana users

  19. Spine formation and maturation in the developing rat auditory cortex.

    PubMed

    Schachtele, Scott J; Losh, Joe; Dailey, Michael E; Green, Steven H

    2011-11-01

    The rat auditory cortex is organized as a tonotopic map of sound frequency. This map is broadly tuned at birth and is refined during the first 3 weeks postnatal. The structural correlates underlying tonotopic map maturation and reorganization during development are poorly understood. We employed fluorescent dye ballistic labeling ("DiOlistics") alone, or in conjunction with immunohistochemistry, to quantify synaptogenesis in the auditory cortex of normal hearing rats. We show that the developmental appearance of dendritic protrusions, which include both immature filopodia and mature spines, on layers 2/3, 4, and 5 pyramidal and layer 4 spiny nonpyramidal neurons occurs in three phases: slow addition of dendritic protrusions from postnatal day 4 (P4) to P9, rapid addition of dendritic protrusions from P9 to P19, and a final phase where mature protrusion density is achieved (>P21). Next, we combined DiOlistics with immunohistochemical labeling of bassoon, a presynaptic scaffolding protein, as a novel method to categorize dendritic protrusions as either filopodia or mature spines in cortex fixed in vivo. Using this method we observed an increase in the spine-to-filopodium ratio from P9-P16, indicating a period of rapid spine maturation. Previous studies report mature spines as being shorter in length compared to filopodia. We similarly observed a reduction in protrusion length between P9 and P16, corroborating our immunohistochemical spine maturation data. These studies show that dendritic protrusion formation and spine maturation occur rapidly at a time previously shown to correspond to auditory cortical tonotopic map refinement (P11-P14), providing a structural correlate of physiological maturation. PMID:21800311

  20. A dorsolateral prefrontal cortex semi-automatic segmenter

    NASA Astrophysics Data System (ADS)

    Al-Hakim, Ramsey; Fallon, James; Nain, Delphine; Melonakos, John; Tannenbaum, Allen

    2006-03-01

    Structural, functional, and clinical studies in schizophrenia have, for several decades, consistently implicated dysfunction of the prefrontal cortex in the etiology of the disease. Functional and structural imaging studies, combined with clinical, psychometric, and genetic analyses in schizophrenia have confirmed the key roles played by the prefrontal cortex and closely linked "prefrontal system" structures such as the striatum, amygdala, mediodorsal thalamus, substantia nigra-ventral tegmental area, and anterior cingulate cortices. The nodal structure of the prefrontal system circuit is the dorsal lateral prefrontal cortex (DLPFC), or Brodmann area 46, which also appears to be the most commonly studied and cited brain area with respect to schizophrenia. 1, 2, 3, 4 In 1986, Weinberger et. al. tied cerebral blood flow in the DLPFC to schizophrenia.1 In 2001, Perlstein et. al. demonstrated that DLPFC activation is essential for working memory tasks commonly deficient in schizophrenia. 2 More recently, groups have linked morphological changes due to gene deletion and increased DLPFC glutamate concentration to schizophrenia. 3, 4 Despite the experimental and clinical focus on the DLPFC in structural and functional imaging, the variability of the location of this area, differences in opinion on exactly what constitutes DLPFC, and inherent difficulties in segmenting this highly convoluted cortical region have contributed to a lack of widely used standards for manual or semi-automated segmentation programs. Given these implications, we developed a semi-automatic tool to segment the DLPFC from brain MRI scans in a reproducible way to conduct further morphological and statistical studies. The segmenter is based on expert neuroanatomist rules (Fallon-Kindermann rules), inspired by cytoarchitectonic data and reconstructions presented by Rajkowska and Goldman-Rakic. 5 It is semi-automated to provide essential user interactivity. We present our results and provide details on our DLPFC open-source tool.