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Sample records for occipital cortex loc

  1. 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

  2. Neural Responses to Central and Peripheral Objects in the Lateral Occipital Cortex

    PubMed Central

    Wang, Bin; Guo, Jiayue; Yan, Tianyi; Ohno, Seiichiro; Kanazawa, Susumu; Huang, Qiang; Wu, Jinglong

    2016-01-01

    Human object recognition and classification depend on the retinal location where the object is presented and decrease as eccentricity increases. The lateral occipital complex (LOC) is thought to be preferentially involved in the processing of objects, and its neural responses exhibit category biases to objects presented in the central visual field. However, the nature of LOC neural responses to central and peripheral objects remains largely unclear. In the present study, we used functional magnetic resonance imaging (fMRI) and a wide-view presentation system to investigate neural responses to four categories of objects (faces, houses, animals, and cars) in the primary visual cortex (V1) and the lateral visual cortex, including the LOC and the retinotopic areas LO-1 and LO-2. In these regions, the neural responses to objects decreased as the distance between the location of presentation and center fixation increased, which is consistent with the diminished perceptual ability that was found for peripherally presented images. The LOC and LO-2 exhibited significantly positive neural responses to all eccentricities (0–55°), but LO-1 exhibited significantly positive responses only to central eccentricities (0–22°). By measuring the ratio relative to V1 (RRV1), we further demonstrated that eccentricity, category and the interaction between them significantly affected neural processing in these regions. LOC, LO-1, and LO-2 exhibited larger RRV1s when stimuli were presented at an eccentricity of 0° compared to when they were presented at the greater eccentricities. In LOC and LO-2, the RRV1s for images of faces, animals and cars showed an increasing trend when the images were presented at eccentricities of 11 to 33°. However, the RRV1s for houses showed a decreasing trend in LO-1 and no difference in the LOC and LO-2. We hypothesize, that when houses and the images in the other categories were presented in the peripheral visual field, they were processed via different strategies in the lateral visual cortex. PMID:26924972

  3. Neural Responses to Central and Peripheral Objects in the Lateral Occipital Cortex.

    PubMed

    Wang, Bin; Guo, Jiayue; Yan, Tianyi; Ohno, Seiichiro; Kanazawa, Susumu; Huang, Qiang; Wu, Jinglong

    2016-01-01

    Human object recognition and classification depend on the retinal location where the object is presented and decrease as eccentricity increases. The lateral occipital complex (LOC) is thought to be preferentially involved in the processing of objects, and its neural responses exhibit category biases to objects presented in the central visual field. However, the nature of LOC neural responses to central and peripheral objects remains largely unclear. In the present study, we used functional magnetic resonance imaging (fMRI) and a wide-view presentation system to investigate neural responses to four categories of objects (faces, houses, animals, and cars) in the primary visual cortex (V1) and the lateral visual cortex, including the LOC and the retinotopic areas LO-1 and LO-2. In these regions, the neural responses to objects decreased as the distance between the location of presentation and center fixation increased, which is consistent with the diminished perceptual ability that was found for peripherally presented images. The LOC and LO-2 exhibited significantly positive neural responses to all eccentricities (0-55°), but LO-1 exhibited significantly positive responses only to central eccentricities (0-22°). By measuring the ratio relative to V1 (RRV1), we further demonstrated that eccentricity, category and the interaction between them significantly affected neural processing in these regions. LOC, LO-1, and LO-2 exhibited larger RRV1s when stimuli were presented at an eccentricity of 0° compared to when they were presented at the greater eccentricities. In LOC and LO-2, the RRV1s for images of faces, animals and cars showed an increasing trend when the images were presented at eccentricities of 11 to 33°. However, the RRV1s for houses showed a decreasing trend in LO-1 and no difference in the LOC and LO-2. We hypothesize, that when houses and the images in the other categories were presented in the peripheral visual field, they were processed via different strategies in the lateral visual cortex. PMID:26924972

  4. 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

  5. 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

  6. The causal role of the occipital face area (OFA) and lateral occipital (LO) cortex in symmetry perception.

    PubMed

    Bona, Silvia; Cattaneo, Zaira; Silvanto, Juha

    2015-01-14

    Symmetry is an important cue in face and object perception. Here we used fMRI-guided transcranial magnetic stimulation (TMS) to shed light on the role of the occipital face area (OFA), a key region in face processing, and the lateral occipital (LO) cortex, a key area in object processing, in symmetry detection. In the first experiment, we applied TMS over the rightOFA, its left homolog (leftOFA), rightLO, and vertex (baseline) while participants were discriminating between symmetric and asymmetric dot patterns. Stimulation of rightOFA and rightLO impaired performance, causally implicating these two regions in detection of symmetry in low-level dot configurations. TMS over rightLO but not rightOFA also significantly impaired detection of nonsymmetric shapes defined by collinear Gabor patches, demonstrating that rightOFA responds to symmetry but not to all cues mediating figure-ground segregation. The second experiment showed a causal role for rightOFA but not rightLO in facial symmetry detection. Overall, our results demonstrate that both the rightOFA and rightLO are sensitive to symmetry in dot patterns, whereas only rightOFA is causally involved in facial symmetry detection. PMID:25589766

  7. Functional specialization in rat occipital and temporal visual cortex.

    PubMed

    Vermaercke, Ben; Gerich, Florian J; Ytebrouck, Ellen; Arckens, Lutgarde; Op de Beeck, Hans P; Van den Bergh, Gert

    2014-10-15

    Recent studies have revealed a surprising degree of functional specialization in rodent visual cortex. Anatomically, suggestions have been made about the existence of hierarchical pathways with similarities to the ventral and dorsal pathways in primates. Here we aimed to characterize some important functional properties in part of the supposed "ventral" pathway in rats. We investigated the functional properties along a progression of five visual areas in awake rats, from primary visual cortex (V1) over lateromedial (LM), latero-intermediate (LI), and laterolateral (LL) areas up to the newly found lateral occipito-temporal cortex (TO). Response latency increased >20 ms from areas V1/LM/LI to areas LL and TO. Orientation and direction selectivity for the used grating patterns increased gradually from V1 to TO. Overall responsiveness and selectivity to shape stimuli decreased from V1 to TO and was increasingly dependent upon shape motion. Neural similarity for shapes could be accounted for by a simple computational model in V1, but not in the other areas. Across areas, we find a gradual change in which stimulus pairs are most discriminable. Finally, tolerance to position changes increased toward TO. These findings provide unique information about possible commonalities and differences between rodents and primates in hierarchical cortical processing. PMID:24990566

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

    PubMed Central

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

    2013-01-01

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

  9. Right occipital cortex activation correlates with superior odor processing performance in the early blind.

    PubMed

    Renier, Laurent; Cuevas, Isabel; Grandin, Cécile B; Dricot, Laurence; Plaza, Paula; Lerens, Elodie; Rombaux, Philippe; De Volder, Anne G

    2013-01-01

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

  10. 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

  11. 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

  12. MEG reveals a fast pathway from somatosensory cortex to occipital areas via posterior parietal cortex in a blind subject

    PubMed Central

    Ioannides, Andreas A.; Liu, Lichan; Poghosyan, Vahe; Saridis, George A.; Gjedde, Albert; Ptito, Maurice; Kupers, Ron

    2013-01-01

    Cross-modal activity in visual cortex of blind subjects has been reported during performance of variety of non-visual tasks. A key unanswered question is through which pathways non-visual inputs are funneled to the visual cortex. Here we used tomographic analysis of single trial magnetoencephalography (MEG) data recorded from one congenitally blind and two sighted subjects after stimulation of the left and right median nerves at three intensities: below sensory threshold, above sensory threshold and above motor threshold; the last sufficient to produce thumb twitching. We identified reproducible brain responses in the primary somatosensory (S1) and motor (M1) cortices at around 20 ms post-stimulus, which were very similar in sighted and blind subjects. Time-frequency analysis revealed strong 45–70 Hz activity at latencies of 20–50 ms in S1 and M1, and posterior parietal cortex Brodmann areas (BA) 7 and 40, which compared to lower frequencies, were substantially more pronounced in the blind than the sighted subjects. Critically, at frequencies from α-band up to 100 Hz we found clear, strong, and widespread responses in the visual cortex of the blind subject, which increased with the intensity of the somatosensory stimuli. Time-delayed mutual information (MI) revealed that in blind subject the stimulus information is funneled from the early somatosensory to visual cortex through posterior parietal BA 7 and 40, projecting first to visual areas V5 and V3, and eventually V1. The flow of information through this pathway occurred in stages characterized by convergence of activations into specific cortical regions. In sighted subjects, no linked activity was found that led from the somatosensory to the visual cortex through any of the studied brain regions. These results provide the first evidence from MEG that in blind subjects, tactile information is routed from primary somatosensory to occipital cortex via the posterior parietal cortex. PMID:23935576

  13. Orienting Auditory Spatial Attention Engages Frontal Eye Fields and Medial Occipital Cortex in Congenitally Blind Humans

    PubMed Central

    Garg, Arun; Schwartz, Daniel; Stevens, Alexander A.

    2007-01-01

    What happens in vision related cortical areas when congenitally blind (CB) individuals orient attention to spatial locations? Previous neuroimaging of sighted individuals has found overlapping activation in a network of frontoparietal areas including frontal eye-fields (FEF), during both overt (with eye movement) and covert (without eye movement) shifts of spatial attention. Since voluntary eye movement planning seems irrelevant in CB, their FEF neurons should be recruited for alternative functions if their attentional role in sighted individuals is only due to eye movement planning. Recent neuroimaging of the blind has also reported activation in medial occipital areas, normally associated with visual processing, during a diverse set of non-visual tasks, but their response to attentional shifts remains poorly understood. Here, we used event-related fMRI to explore FEF and medial occipital areas in CB individuals and sighted controls with eyes closed (SC) performing a covert attention orienting task, using endogenous verbal cues and spatialized auditory targets. We found robust stimulus-locked FEF activation of all CB subjects, similar but stronger than in SC, suggesting that FEF plays a role in endogenous orienting of covert spatial attention even in individuals in whom voluntary eye movements are irrelevant. We also found robust activation in bilateral medial occipital cortex in CB but not in SC subjects. The response decreased below baseline following endogenous verbal cues but increased following auditory targets, suggesting that the medial occipital area in CB does not directly engage during cued orienting of attention but may be recruited for processing of spatialized auditory targets. PMID:17397882

  14. LOC689986, a unique gene showing specific expression in restricted areas of the rodent neocortex

    PubMed Central

    2013-01-01

    Background The neocortex is a highly specialised and complex brain structure, involved in numerous tasks, ranging from processing and interpretation of somatosensory information, to control of motor functions. The normal function linked to distinct neocortical areas might involve control of highly specific gene expression, and in order to identify such regionally enriched genes, we previously analysed the global gene expression in three different cortical regions (frontomedial, temporal and occipital cortex) from the adult rat brain. We identified distinct sets of differentially expressed genes. One of these genes, namely the hypothetical protein LOC689986 (LOC689986), was of particular interest, due to an almost exclusive expression in the temporal cortex. Results Detailed analysis of LOC689986 in the adult rat brain confirmed the expression in confined areas of parieto-temporal cortex, and revealed highly specific expression in layer 4 of the somatosensory cortex, with sharp borders towards the neighbouring motor cortex. In addition, LOC689986 was found to be translated in vivo, and was detected in the somatosensory cortex and in the Purkinje cells of the cerebellar cortex. The protein was present in neuronal dendrites and also in astrocyte cells. Finally, this unique gene is apparently specific for, and highly conserved in, the vertebrate lineage. Conclusions In this study, we have partially characterised the highly conserved LOC689986 gene, which is specific to the vertebrate linage. The gene displays a distinct pattern of expression in layer 4 of the somatosensory cortex, and areas of the parieto-temporal cortex in rodents. PMID:23844656

  15. Top–down flow of visual spatial attention signals from parietal to occipital cortex

    PubMed Central

    Lauritzen, Thomas Z.; D’Esposito, Mark; Heeger, David J.; Silver, Michael A.

    2010-01-01

    Given the complexity of our visual environment, the ability to selectively attend to certain locations, while ignoring others, is crucial for reducing the amount of visual information to manageable levels and for optimizing behavioral performance. Sustained allocation of spatial attention causes persistent increases in functional magnetic resonance imaging (fMRI) signals in portions of early visual cortex that retinotopically represent the attended location, even in the absence of a visual stimulus. Here we test the hypothesis that topographically organized posterior parietal cortical areas IPS1 and IPS2 transmit top–down spatial attention signals to early visual cortex. We employed fMRI and coherency analysis to measure functional connectivity among cortical areas V1, V2, V3, V3A, V3B, V7, IPS1, and IPS2 during sustained visual spatial attention. Attention increased the magnitude of coherency for many pairs of areas in occipital and parietal cortex. Additionally, attention-related activity in IPS1 and IPS2 led activity in several visual cortical areas by a few hundred milliseconds. These results are consistent with transmission of top–down spatial attention signals from IPS1 and IPS2 to early visual cortex. PMID:20055551

  16. 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

  17. Recruitment of Occipital Cortex during Sensory Substitution Training Linked to Subjective Experience of Seeing in People with Blindness

    PubMed Central

    Ortiz, Tomás; Poch, Joaquín; Santos, Juan M.; Requena, Carmen; Martínez, Ana M.; Ortiz-Terán, Laura; Turrero, Agustín; Barcia, Juan; Nogales, Ramón; Calvo, Agustín; Martínez, José M.; Córdoba, José L.; Pascual-Leone, Alvaro

    2011-01-01

    Over three months of intensive training with a tactile stimulation device, 18 blind and 10 blindfolded seeing subjects improved in their ability to identify geometric figures by touch. Seven blind subjects spontaneously reported ‘visual qualia’, the subjective sensation of seeing flashes of light congruent with tactile stimuli. In the latter subjects tactile stimulation evoked activation of occipital cortex on electroencephalography (EEG). None of the blind subjects who failed to experience visual qualia, despite identical tactile stimulation training, showed EEG recruitment of occipital cortex. None of the blindfolded seeing humans reported visual-like sensations during tactile stimulation. These findings support the notion that the conscious experience of seeing is linked to the activation of occipital brain regions in people with blindness. Moreover, the findings indicate that provision of visual information can be achieved through non-visual sensory modalities which may help to minimize the disability of blind individuals, affording them some degree of object recognition and navigation aid. PMID:21853098

  18. 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

  19. Repetition Suppression for Speech Processing in the Associative Occipital and Parietal Cortex of Congenitally Blind Adults

    PubMed Central

    Arnaud, Laureline; Sato, Marc; Ménard, Lucie; Gracco, Vincent L.

    2013-01-01

    In the congenitally blind (CB), sensory deprivation results in cross-modal plasticity, with visual cortical activity observed for various auditory tasks. This reorganization has been associated with enhanced auditory abilities and the recruitment of visual brain areas during sound and language processing. The questions we addressed are whether visual cortical activity might also be observed in CB during passive listening to auditory speech and whether cross-modal plasticity is associated with adaptive differences in neuronal populations compared to sighted individuals (SI). We focused on the neural substrate of vowel processing in CB and SI adults using a repetition suppression (RS) paradigm. RS has been associated with enhanced or accelerated neural processing efficiency and synchronous activity between interacting brain regions. We evaluated whether cortical areas in CB were sensitive to RS during repeated vowel processing and whether there were differences across the two groups. In accordance with previous studies, both groups displayed a RS effect in the posterior temporal cortex. In the blind, however, additional occipital, temporal and parietal cortical regions were associated with predictive processing of repeated vowel sounds. The findings suggest a more expanded role for cross-modal compensatory effects in blind persons during sound and speech processing and a functional transfer of specific adaptive properties across neural regions as a consequence of sensory deprivation at birth. PMID:23717628

  20. Occipital cortex activation by long-term repetitive tactile stimulation is necessary for object recognition in blinds: a case report.

    PubMed

    Ortiz, Tomás; Poch, Joaquín; Santos, Juan M; Martínez, Ana M; Ortiz-Terán, Laura; Requena, Carmen; Barcia, Juan A; de Erausquin, Gabriel A; Pascual-Leone, Alvaro

    2014-06-01

    Tactile vision has been approached from a variety of angles using different techniques. So far, a certain kind of object (and text) recognition has been shown, though seeing as such has not been achieved yet, and it remains unclear. Trough repetitive passive tactile stimulation perceptual processing is transferred from temporo-parietal to occipital areas, which affects object recognition. We report the results of passive tactile stimulation, as well as rTMS, applied to a 50 year old left handed blind male with over 97% loss of vision, who suffers from Peter's anomaly and microphthalmia. After 15 weeks of passive tactile stimulation, the subject showed increased activity in occipital areas associated with the development of visual-like perception which remained unchanged after three months without passive tactile stimulation. Inhibitory rTMS over the visual cortex led to noticeable reduction of spatial recognition performance and visual sensations in this subject. Stable changes in occipital cortical activity can be associated with subjective sensations of seeing. Once occipital activation has been achieved, it is necessary for spatial object recognition. Both facts highlight the implication of occipital areas in tactile vision and the cortical plasticity of passive tactile long-term stimulation in people with blindness. PMID:23819463

  1. Functional interactions of feature-selective responses in MT+ and LOC and primary visual cortex in dynamic feature interpolation during apparent motion.

    PubMed

    Ma, Feilong; Shim, Won Mok

    2015-01-01

    When a static stimulus appears at two locations in succession, one can perceive the illusion of apparent motion (AM) across the two locations. Previous research using fMRI and a forward encoding model shows that intermediate visual features of a transforming object, which are absent in the retinal input but are spatiotemporally interpolated during AM, are reconstructed in population-level feature-selective tuning responses in the region of V1 corresponding to the AM path (Familiar, Chong, & Shim, 2014 VSS). However, little is known about how this interpolated feature information is reconstructed in non-stimulated regions of early visual cortex via top-down processing. Here using fMRI and a novel method of feature channel-based functional connectivity we examined functional interactions between the region of V1 that is retinotopically mapped to the AM path (V1-AM path) and high-level visual areas that are implicated in motion and shape processing (MT+ and LOC) during the perception of AM. Participants viewed rotational AM between two oriented gratings in the periphery and the population-level orientation channel responses in the V1-AM path, MT+ and LOC ROIs were reconstructed. We used the response at each orientation channel as input to compute channel-based inter-area correlations between V1 and each of the higher-level areas. The results showed that correlations between V1-AM path and MT+, as well as V1-AM path and LOC, were higher at orientation channels corresponding to the interpolated orientations on the AM path (0° or 90° depending on AM condition) when AM was perceived compared to when AM was abolished by simultaneously presenting the two gratings. This channel-selective increase in functional connectivity was not evident at other orientation channels. These results suggest that signals from high-level motion and shape processing areas, such as MT+ and LOC, may provide feedback information that mediates dynamic feature reconstruction in early retinotopic cortex during AM. Meeting abstract presented at VSS 2015. PMID:26326175

  2. Phosphene-guided transcranial magnetic stimulation of occipital but not parietal cortex suppresses stimulus visibility

    PubMed Central

    Tapia, Evelina; Mazzi, Chiara; Savazzi, Silvia; Beck, Diane M.

    2014-01-01

    Transcranial magnetic stimulation (TMS) applied over the occipital lobe approximately 100 ms after the onset of a stimulus decreases its visibility if it appears in the location of the phosphene. Because phosphenes can also be elicited by stimulation of the parietal regions, we asked if the same procedure that is used to reduce visibility of stimuli with occipital TMS will lead to decreased stimulus visibility when TMS is applied to parietal regions. TMS was randomly applied at 0 to 130 ms after the onset of the stimulus (SOA) in steps of 10 ms in occipital and parietal regions. Participants responded to the orientation of the line stimulus and rated its visibility. We replicate previous reports of phosphenes from both occipital and parietal TMS. As previously reported, we also observed visual suppression around the classical 100 ms window both in the objective line orientation and subjective visibility responses with occipital TMS. Parietal stimulation, on the other hand, did not consistently reduce stimulus visibility in any time window. PMID:24584900

  3. Gene expression in the rat brain: High similarity but unique differences between frontomedial-, temporal- and occipital cortex

    PubMed Central

    2011-01-01

    Background The six-layered neocortex of the mammalian brain may appear largely homologous, but is in reality a modular structure of anatomically and functionally distinct areas. However, global gene expression seems to be almost identical across the cerebral cortex and only a few genes have so far been reported to show regional enrichment in specific cortical areas. Results In the present study on adult rat brain, we have corroborated the strikingly similar gene expression among cortical areas. However, differential expression analysis has allowed for the identification of 30, 24 and 11 genes enriched in frontomedial -, temporal- or occipital cortex, respectively. A large proportion of these 65 genes appear to be involved in signal transduction, including the ion channel Fxyd6, the neuropeptide Grp and the nuclear receptor Rorb. We also find that the majority of these genes display increased expression levels around birth and show distinct preferences for certain cortical layers and cell types in rodents. Conclusions Since specific patterns of expression often are linked to equally specialised biological functions, we propose that these cortex sub-region enriched genes are important for proper functioning of the cortical regions in question. PMID:21269499

  4. Anodal-tDCS over the human right occipital cortex enhances the perception and memory of both faces and objects.

    PubMed

    Barbieri, Marica; Negrini, Marcello; Nitsche, Michael A; Rivolta, Davide

    2016-01-29

    Accurate face processing skills are pivotal for typical social cognition, and impairments in this ability characterise various clinical conditions (e.g., prosopagnosia). No study to date has investigated whether transcranial direct current stimulation (tDCS) can causally enhance face processing. In addition, the category- and the process-specificity of tDCS effects, as well as the role of the timing of neuromodulation with respect to the execution of cognitive tasks are still unknown. In this single-blind, sham-controlled study, we examined whether the administration of anodal-tDCS (a-tDCS) over the right occipital cortex of healthy volunteers (N=64) enhances performance on perceptual and memory tasks involving both face and object stimuli. Neuromodulation was delivered in two conditions: online (a-tDCS during task execution) and offline (a-tDCS before task execution). The results demonstrate that offline a-tDCS enhances the perception and memory performance of both faces and objects. There was no effect of online a-tDCS on behaviour. Furthermore, the offline effect was site-specific since a-tDCS over the sensory-motor cortex did not lead to behavioural changes. Our results add relevant information about the breadth of cognitive processes and visual stimuli that can be modulated by tDCS, and about the design of effective neuromodulation protocols, which have implications for advancing theories in cognitive neuroscience and clinical applications. PMID:26744225

  5. Transient decrease in water diffusion observed in human occipital cortex during visual stimulation

    PubMed Central

    Darquié, Anne; Poline, Jean-Baptiste; Poupon, Cyril; Saint-Jalmes, Hervé; Le Bihan, Denis

    2001-01-01

    Using MRI, we report the observation of a transient decrease of the apparent diffusion coefficient (ADC) of water in the human brain visual cortex during activation by a black and white 8-Hz-flickering checkerboard. The ADC decrease was small (<1%), but significant and reproducible, and closely followed the time course of the activation paradigm. Based on the known sensitivity of diffusion MRI to cell size in tissues and on optical imaging studies that have revealed changes in the shape of neurons and glial cells during activation, the observed ADC findings have been tentatively ascribed to a transient swelling of cortical cells. These preliminary results suggest a new approach to produce images of brain activation with MRI from signals directly associated with neuronal activation, and not through changes in local blood flow. PMID:11459931

  6. 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

  7. Shape from sound: evidence for a shape operator in the lateral occipital cortex.

    PubMed

    James, Thomas W; Stevenson, Ryan A; Kim, Sunah; Vanderklok, Ross M; James, Karin Harman

    2011-06-01

    A recent view of cortical functional specialization suggests that the primary organizing principle of the cortex is based on task requirements, rather than sensory modality. Consistent with this view, recent evidence suggests that a region of the lateral occipitotemporal cortex (LO) may process object shape information regardless of the modality of sensory input. There is considerable evidence that area LO is involved in processing visual and haptic shape information. However, sound can also carry acoustic cues to an object's shape, for example, when a sound is produced by an object's impact with a surface. Thus, the current study used auditory stimuli that were created from recordings of objects impacting a hard surface to test the hypothesis that area LO is also involved in auditory shape processing. The objects were of two shapes, rods and balls, and of two materials, metal and wood. Subjects were required to categorize the impact sounds in one of three tasks, (1) by the shape of the object while ignoring material, (2) by the material of the object while ignoring shape, or (3) by using all the information available. Area LO was more strongly recruited when subjects discriminated impact sounds based on the shape of the object that made them, compared to when subjects discriminated those same sounds based on material. The current findings suggest that activation in area LO is shape selective regardless of sensory input modality, and are consistent with an emerging theory of perceptual functional specialization of the brain that is task-based rather than sensory modality-based. PMID:21397616

  8. rTMS of medial parieto-occipital cortex interferes with attentional reorienting during attention and reaching tasks.

    PubMed

    Ciavarro, Marco; Ambrosini, Ettore; Tosoni, Annalisa; Committeri, Giorgia; Fattori, Patrizia; Galletti, Claudio

    2013-09-01

    Unexpected changes in the location of a target for an upcoming action require both attentional reorienting and motor planning update. In both macaque and human brain, the medial posterior parietal cortex is involved in both phenomena but its causal role is still unclear. Here we used on-line rTMS over the putative human V6A (pV6A), a reach-related region in the dorsal part of the anterior bank of the parieto-occipital sulcus, during an attention and a reaching task requiring covert shifts of attention and planning of reaching movements toward cued targets in space. We found that rTMS increased RTs to invalidly cued but not to validly cued targets during both the attention and reaching task. Furthermore, we found that rTMS induced a deviation of reaching endpoints toward visual fixation and that this deviation was larger for invalidly cued targets. The results suggest that reorienting signals are used by human pV6A area to rapidly update the current motor plan or the ongoing action when a behaviorally relevant object unexpectedly occurs in an unattended location. The current findings suggest a direct involvement of the action-related dorso-medial visual stream in attentional reorienting and a more specific role of pV6A area in the dynamic, on-line control of reaching actions. PMID:23647519

  9. Dynamic Modulation of Local Population Activity by Rhythm Phase in Human Occipital Cortex During a Visual Search Task

    PubMed Central

    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 (δ, θ, α, β, and γ band) rhythms and the amplitude of broadband spectral change. In the θ and β 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

  10. Microcircuitry of agranular frontal cortex: contrasting laminar connectivity between occipital and frontal areas.

    PubMed

    Ninomiya, Taihei; Dougherty, Kacie; Godlove, David C; Schall, Jeffrey D; Maier, Alexander

    2015-05-01

    Neocortex is striking in its laminar architecture. Tracer studies have uncovered anatomical connectivity among laminae, but the functional connectivity between laminar compartments is still largely unknown. Such functional connectivity can be discerned through spontaneous neural correlations during rest. Previous work demonstrated a robust pattern of mesoscopic resting-state connectivity in macaque primary visual cortex (V1) through interlaminar cross-frequency coupling. Here we investigated whether this pattern generalizes to other cortical areas by comparing resting-state laminar connectivity between V1 and the supplementary eye field (SEF), a frontal area lacking a granular layer 4 (L4). Local field potentials (LFPs) were recorded with linear microelectrode arrays from all laminae of granular V1 and agranular SEF while monkeys rested in darkness. We found substantial differences in the relationship between the amplitude of gamma-band (>30 Hz) LFP and the phase of alpha-band (7-14 Hz) LFP between these areas. In V1, gamma amplitudes in L2/3 and L5 were coupled with alpha-band LFP phase in L5, as previously described. In contrast, in SEF phase-amplitude coupling was prominent within L3 and much weaker across layers. These results suggest that laminar interactions in agranular SEF are unlike those in granular V1. Thus the intrinsic functional connectivity of the cortical microcircuit does not seem to generalize across cortical areas. PMID:25744881

  11. Cytoarchitecture of the human lateral occipital cortex: mapping of two extrastriate areas hOc4la and hOc4lp.

    PubMed

    Malikovic, Aleksandar; Amunts, Katrin; Schleicher, Axel; Mohlberg, Hartmut; Kujovic, Milenko; Palomero-Gallagher, Nicola; Eickhoff, Simon B; Zilles, Karl

    2016-05-01

    The microstructural correlates of the functional segregation of the human lateral occipital cortex are largely unknown. Therefore, we analyzed the cytoarchitecture of this region in ten human post-mortem brains using an observer-independent and statistically testable parcellation method to define the position and extent of areas in the lateral occipital cortex. Two new cytoarchitectonic areas were found: an anterior area hOc4la and a posterior area hOc4lp. hOc4la was located behind the anterior occipital sulcus in rostral and ventral portions of this region where it occupies the anterior third of the middle and inferior lateral occipital gyri. hOc4lp was found in caudal and dorsal portions of this region where it extends along the superior and middle lateral occipital gyri. The cytoarchitectonic areas were registered to 3D reconstructions of the corresponding brains, which were subsequently spatially normalized to the Montreal Neurological Institute reference space. Continuous probabilistic maps of both areas based on the analysis of ten brains were generated to characterize their inter-subject variability in location and size. The maps of hOc4la and hOc4lp were then used as seeds for meta-analytic connectivity modeling and quantitative functional decoding to identify their co-activation patterns and assignment to functional domains. Convergent evidence from their location, topography, size, functional domains and connectivity indicates that hOc4la and hOc4lp are the potential anatomical correlates of the functionally defined lateral occipital areas LO-1 and LO-2. PMID:25687261

  12. Occipital Neuralgia

    MedlinePlus

    ... better ways to treat occipital neuralgia. NIH Patient Recruitment for Occipital Neuralgia Clinical Trials At NIH Clinical Center Throughout the U.S. and Worldwide NINDS Clinical Trials Organizations Column1 Column2 American Chronic Pain Association (ACPA) P. ...

  13. Activity in the lateral occipital cortex between 200 and 300 ms distinguishes between physically identical seen and unseen stimuli

    PubMed Central

    Liu, Ying; Paradis, Anne-Lise; Yahia-Cherif, Lydia; Tallon-Baudry, Catherine

    2012-01-01

    There is converging evidence that electrophysiological responses over posterior cortical regions in the 200300 ms range distinguish between physically identical stimuli that reach consciousness or remain unseen. Here, we attempt at determining the sources of this awareness-related activity using magneto-encephalographic (MEG). Fourteen subjects were presented with faint colored gratings at threshold for contrast and reported on each trial whether the grating was seen or unseen. Subjects were primed with a color cue that could be congruent or incongruent with the color of the grating, to probe to what extent two co-localized features (color and orientation) would be bound in consciousness. The contrast between neural responses to seen and unseen physically identical gratings revealed a sustained posterior difference between 190 and 350 ms, thereby replicating prior studies. We further show that the main sources of the awareness-related activity were localized bilaterally on the lateral convexity of the occipito-temporal region, in the Lateral Occipital (LO) complex, as well as in the right posterior infero-temporal region. No activity differentiating seen and unseen trials could be observed in frontal or parietal regions in this latency range, even at lower threshold. Color congruency did not improve grating's detection, and the awareness-related activity was independent from color congruency. However, at the neural level, color congruency was processed differently in grating-present and grating-absent trials. The pattern of results suggests the existence of a neural process of color congruency engaging left parietal regions that is affected by the mere presence of another feature, whether this feature reaches consciousness or not. Altogether, our results reveal an occipital source of visual awareness insensitive to color congruency, and a simultaneous parietal source not engaged in visual awareness, but sensitive to the manipulation of co-localized features. PMID:22848195

  14. Task-Related Dynamic Division of Labor Between Anterior Temporal and Lateral Occipital Cortices in Representing Object Size

    PubMed Central

    2016-01-01

    Object size is represented by functionally distinct sectors along the ventral visual pathway. The early visual cortex encodes objects' sensory-retinal size. Subsequently, the occipitotemporal cortex computes objects' canonical size based on statistical regularities of visual features. Although the neurocomputation of size has been studied in a “bottom-up” sensory-driven framework, little is known about how perceptual size information is transformed into conceptual knowledge and how this computation is modulated by “top-down” goal-driven signals. Using continuous theta burst stimulation, we demonstrated that behavioral goal shapes the neurocognitive network underpinning object size. We manipulated the congruency of perceptual versus conceptual object size, which provides a robust behavioral probe reflecting implicit size knowledge. Neurostimulation was targeted at the lateral occipital cortex (LOC), a key region for object perception, or the anterior temporal lobe (ATL), a “hub” of supramodal conceptual processing. We observed striking contextual modulation of the neurocognitive architecture: when human participants judged perceptual size, the congruency effect was significantly attenuated by LOC stimulation but stayed resilient to ATL stimulation. By contrast, when they judged conceptual size, both LOC and ATL stimulation eradicated the otherwise robust effect. Our findings demonstrate disparate functional profiles of the LOC and ATL, providing the first evidence of a malleable network adaptively altering its division of labor with top-down states. The LOC, regardless of task demand, automatically represents “bottom-up” statistical regularities of visual conformation (reflecting typical object size), whereas the ATL contributes to this computation when the context requires semantically based linkage of visual attributes to object recognition. SIGNIFICANCE STATEMENT In the present study, we provide compelling evidence that the “top-down” cognitive state of an observer changes the dynamic interaction between different subregions of the ventral temporal cortex. Using inhibitory neurostimulation combined with a novel paradigm, we demonstrate a flexible division of labor in the neurocognitive architecture that underpins size knowledge: the lateral occipital cortex codes perceptually based aspects (statistical visual configuration of small/large objects), whereas the anterior temporal lobe represents semantically based aspects (object identity), with their involvement interactively weighted by task demand. The interactive nature of the ventral temporal cortex highlights how top-down modulation constrains and shapes neural representations in the visual system. PMID:27122025

  15. 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

  16. Occipital bending in depression.

    PubMed

    Maller, Jerome J; Thomson, Richard H S; Rosenfeld, Jeffrey V; Anderson, Rodney; Daskalakis, Zafiris J; Fitzgerald, Paul B

    2014-06-01

    There are reports of differences in occipital lobe asymmetry within psychiatric populations when compared with healthy control subjects. Anecdotal evidence and enlarged lateral ventricles suggests that there may also be a different pattern of curvature whereby one occipital lobe wraps around the other, termed 'occipital bending'. We investigated the prevalence of occipital bending in 51 patients with major depressive disorder (males mean age = 41.96 ± 14.00 years, females mean age = 40.71 ± 12.41 years) and 48 age- and sex-matched healthy control subjects (males mean age = 40.29 ± 10.23 years, females mean age = 42.47 ± 14.25 years) and found the prevalence to be three times higher among patients with major depressive disorder (18/51, 35.3%) when compared with control subjects (6/48, 12.5%). The results suggest that occipital bending is more common among patients with major depressive disorder than healthy subjects, and that occipital asymmetry and occipital bending are separate phenomena. Incomplete neural pruning may lead to the cranial space available for brain growth being restricted, or ventricular enlargement may exacerbate the natural occipital curvature patterns, subsequently causing the brain to become squashed and forced to 'wrap' around the other occipital lobe. Although the clinical implications of these results are unclear, they provide an impetus for further research into the relevance of occipital bending in major depression disorder. PMID:24740986

  17. Objective Assessment of Nuclear and Cortical Cataracts through Scheimpflug Images: Agreement with the LOCS III Scale

    PubMed Central

    2016-01-01

    Purpose To assess nuclear and cortical opacities through the objective analysis of Scheimpflug images, and to check the correlation with the Lens Opacity Classification System III (LOCS III). Methods Nuclear and cortical opacities were graded according to the LOCS III rules after pupil dilation. The maximum and average pixel intensity values along an elliptical mask within the lens nucleus were taken to analyse nuclear cataracts. A new metric based on the percentage of opaque pixels within a region of interest was used to analyse cortical cataracts. The percentage of opaque pixels was also calculated for half, third and quarter areas from the region of interest’s periphery. Results The maximum and average intensity values along the nucleus were directly proportional to the LOCS III grade: The larger the LOCS III value, the larger maximum and average intensity ones. These metrics showed a positive and significant correlation with the LOCS grade: The larger the LOCS grade, the higher was percentage of opaque pixels along the cortex within the same mask’s size. This metric showed a significant correlation to the LOCS grade. Conclusion The metrics used to assess nuclear opacities showed good correlation with the LOCS III. The percentage of opaque pixels showed to be a useful metric to measure objectively the severity of the cortical opacity. These metrics could be implemented in an algorithm to detect and grade lens opacities automatically and objectively. PMID:26890694

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

    PubMed Central

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

    2015-01-01

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

  19. [Photosensitivity, epilepsy, the occipital and frontal cortex].

    PubMed

    Karlov, V A

    2015-01-01

    This article discusses the features of the structural-functional organization of the visual distance perception which, in contrast to other distant sensory systems, has not only afferent but also efferent part--the frontal visual field and, smooth and stripy muscles of the eye which accordingly support the visual function. The increasing importance of the efferent component of the visual system in the present conditions of real and virtual movements of visual objects is shown. The case of photosensitivity in epilepsy proves the fact that the efferent component of the visual system can react in a protective way to the rhythmic photostimulation. PMID:26288280

  20. Atlanto-occipital dislocation

    PubMed Central

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

    2015-01-01

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

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

    PubMed

    Cheung, Olivia; Caramazza, Alfonso

    2015-01-01

    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

  2. Early processing in human LOC is highly responsive to illusory contours but not to salient regions

    PubMed Central

    Shpaner, Marina; Murray, Micah M.; Foxe, John J.

    2011-01-01

    Human electrophysiological studies support a model whereby sensitivity to so-called illusory contour stimuli is first seen within the lateral occipital complex. A challenge to this model posits that the lateral occipital complex is a general site for crude region-based segmentation, based on findings of equivalent hemodynamic activations in the lateral occipital complex to illusory contour and so-called salient region stimuli, a stimulus class that lacks the classic bounding contours of illusory contours. Using high-density electrical mapping of visual evoked potentials, we show that early lateral occipital cortex activity is substantially stronger to illusory contour than to salient region stimuli, while later lateral occipital complex activity is stronger to salient region than to illusory contour stimuli. Our results suggest that equivalent hemodynamic activity to illusory contour and salient region stimuli likely reflects temporally integrated responses, a result of the poor temporal resolution of hemodynamic imaging. The temporal precision of visual evoked potentials is critical for establishing viable models of completion processes and visual scene analysis. We propose that crude spatial segmentation analyses, which are insensitive to illusory contours, occur first within dorsal visual regions, not lateral occipital complex, and that initial illusory contour sensitivity is a function of the lateral occipital complex. PMID:19895562

  3. 48 CFR 732.406-73 - LOC contract clause.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false LOC contract clause. 732.406-73 Section 732.406-73 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL DEVELOPMENT GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING Advance Payments 732.406-73 LOC contract clause. (a) If payment is to be provided by LOC,...

  4. Enhanced visual perception with occipital transcranial magnetic stimulation.

    PubMed

    Mulckhuyse, Manon; Kelley, Todd A; Theeuwes, Jan; Walsh, Vincent; Lavie, Nilli

    2011-10-01

    Transcranial magnetic stimulation (TMS) over the occipital pole can produce an illusory percept of a light flash (or 'phosphene'), suggesting an excitatory effect. Whereas previous reported effects produced by single-pulse occipital pole TMS are typically disruptive, here we report the first demonstration of a location-specific facilitatory effect on visual perception in humans. Observers performed a spatial cueing orientation discrimination task. An orientation target was presented in one of two peripheral placeholders. A single pulse below the phosphene threshold applied to the occipital pole 150 or 200 ms before stimulus onset was found to facilitate target discrimination in the contralateral compared with the ipsilateral visual field. At the 150-ms time window contralateral TMS also amplified cueing effects, increasing both facilitation effects for valid cues and interference effects for invalid cues. These results are the first to show location-specific enhanced visual perception with single-pulse occipital pole stimulation prior to stimulus presentation, suggesting that occipital stimulation can enhance the excitability of visual cortex to subsequent perception. PMID:21848918

  5. 48 CFR 732.406-72 - Establishing an LOC.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Establishing an LOC. 732.406-72 Section 732.406-72 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL DEVELOPMENT GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING Advance Payments 732.406-72 Establishing an LOC. (a) While the contract will provide for the...

  6. 48 CFR 732.406-74 - Revocation of the LOC.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Revocation of the LOC. 732.406-74 Section 732.406-74 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL DEVELOPMENT GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING Advance Payments 732.406-74 Revocation of the LOC. If during the term of the contract...

  7. 48 CFR 732.406-72 - Establishing an LOC.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 5 2012-10-01 2012-10-01 false Establishing an LOC. 732.406-72 Section 732.406-72 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL DEVELOPMENT GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING Advance Payments 732.406-72 Establishing an LOC....

  8. 48 CFR 732.406-72 - Establishing an LOC.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 5 2013-10-01 2013-10-01 false Establishing an LOC. 732.406-72 Section 732.406-72 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL DEVELOPMENT GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING Advance Payments 732.406-72 Establishing an LOC....

  9. 48 CFR 732.406-74 - Revocation of the LOC.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Revocation of the LOC. 732.406-74 Section 732.406-74 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL DEVELOPMENT GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING Advance Payments 732.406-74 Revocation of the LOC....

  10. 48 CFR 732.406-72 - Establishing an LOC.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Establishing an LOC. 732.406-72 Section 732.406-72 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL DEVELOPMENT GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING Advance Payments 732.406-72 Establishing an LOC....

  11. 48 CFR 732.406-74 - Revocation of the LOC.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 5 2013-10-01 2013-10-01 false Revocation of the LOC. 732.406-74 Section 732.406-74 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL DEVELOPMENT GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING Advance Payments 732.406-74 Revocation of the LOC....

  12. 48 CFR 732.406-72 - Establishing an LOC.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Establishing an LOC. 732.406-72 Section 732.406-72 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL DEVELOPMENT GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING Advance Payments 732.406-72 Establishing an LOC....

  13. 48 CFR 732.406-74 - Revocation of the LOC.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 5 2012-10-01 2012-10-01 false Revocation of the LOC. 732.406-74 Section 732.406-74 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL DEVELOPMENT GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING Advance Payments 732.406-74 Revocation of the LOC....

  14. 48 CFR 732.406-74 - Revocation of the LOC.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Revocation of the LOC. 732.406-74 Section 732.406-74 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL DEVELOPMENT GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING Advance Payments 732.406-74 Revocation of the LOC....

  15. The role of sensory cortex and cortical "hubs" in category-specific executive function.

    PubMed

    James, Thomas; Arcurio, Lindsay; Nikoulina, Anastasia

    2015-01-01

    Human executive functions are sensitive to visual cues that make up the environmental context, but there are few research programs that study this influence or study the impact of changes in sensory neural signals on frontal cortical function. In this talk, I will present findings from studies of people with alcohol use disorders (AUD) that implicate the lateral occipital cortex (LOC) and its connections with the anterior insular cortex (AIC) in impulsive decisions-to-drink when exposed to visual alcohol cues. Specifically, 31 women (15 AUD) were scanned using fMRI while performing a decisions-to-drink task. In that task, they were presented with alcohol and food cues that were normed for attractiveness/desirability. They were asked to imagine themselves in a situation where deciding to drink had a high or low probability of a negative consequence and were asked to rate their likelihood of drinking (or eating) on a 4-point scale. AUD women endorsed alcohol cues more than non-AUD, but not food cues - a category-specific effect on decision making. Differences in BOLD signal between AUD women and non-AUD for alcohol vs food cues were widespread and always greater for AUD. This finding suggests that there was no single neural system (e.g., cognitive control) that accounts for the group difference in behavior. Comparing high- to low-risk scenarios highlighted differences between AUD and non-AUD in the LOC and AIC. A task-based functional connectivity analyses provided further support for the role of LOC and AIC in AUD women producing more impulsive category-specific decisions. In conclusion, widespread differences in decision-related BOLD signal between AUD and non-AUD may originate in the visual cortex (LOC) and cascade throughout the brain by way of network "hubs" such as the AIC. These results highlight the important (but underappreciated) role of sensory cortices in decision making and other executive functions. Meeting abstract presented at VSS 2015. PMID:26326143

  16. 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).

  17. LocSigDB: a database of protein localization signals

    PubMed Central

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

    2015-01-01

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

  18. A Preliminary Examination of Loss of Control Eating Disorder (LOC-ED) in Middle Childhood

    PubMed Central

    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.

    2015-01-01

    Loss of Control Eating Disorder (LOC-ED) has been proposed as a diagnostic category for children 6–12y 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 (10.29y ± 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

  19. 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

    2015-01-01

    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

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

    PubMed Central

    Bettencourt, Katherine C.; Xu, Yaoda

    2015-01-01

    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 reported in superior intraparietal sulcus (IPS) but robust multivariate decoding 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 significantly 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, these results show that superior IPS, not occipital cortex, plays a central role in VSTM storage. PMID:26595654

  1. 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

  2. Malignant hemangioendothelioma of occipital bone

    PubMed Central

    Bhake, Arvind; Banode, Pankaj; Singh, Brij Raj

    2012-01-01

    Epithelioidhemangioendothelioma is a rare vascular tumor of bone, and rarely these lesions can present as unique and extremely aggressive tumor. We report a case of highly aggressive epithelioidhemangioendothelioma and discuss the imaging findings. CT brain plain study revealed a poorly-defined, mixed density expansile and lytic lesion involving the occipital bone with extension to the left side with poorly defined trabecula formation. There was significant but irregular enhancement after intravenous administration of contrast material and also marked bone destruction. Microscopic examination of the fine needle aspiration cytology showed a tumor composed of vascular channels lined by plump endothelial cells, which had enlarged hyperchromatic nuclei. In view of the extensive infiltration the patient was submitted for the radiotherapy. PMID:23359640

  3. 48 CFR 732.406-73 - LOC contract clause.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...) If payment is to be provided by LOC, the contract shall contain the clause in subsection 752.232-70. (b) Contracting offices shall ensure that an appropriate (48 CFR) FAR payment clause is also included....406-73 Section 732.406-73 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL...

  4. 48 CFR 732.406-73 - LOC contract clause.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...) If payment is to be provided by LOC, the contract shall contain the clause in subsection 752.232-70. (b) Contracting offices shall ensure that an appropriate (48 CFR) FAR payment clause is also included....406-73 Section 732.406-73 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL...

  5. 48 CFR 732.406-73 - LOC contract clause.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...) If payment is to be provided by LOC, the contract shall contain the clause in subsection 752.232-70. (b) Contracting offices shall ensure that an appropriate (48 CFR) FAR payment clause is also included....406-73 Section 732.406-73 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL...

  6. 48 CFR 732.406-73 - LOC contract clause.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...) If payment is to be provided by LOC, the contract shall contain the clause in subsection 752.232-70. (b) Contracting offices shall ensure that an appropriate (48 CFR) FAR payment clause is also included....406-73 Section 732.406-73 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL...

  7. Alterations of the occipital lobe in schizophrenia

    PubMed Central

    Tohid, Hassaan; Faizan, Muhammad; Faizan, Uzma

    2015-01-01

    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

  8. Occipital Cortical Thickness Predicts Performance on Pitch and Musical Tasks in Blind Individuals

    PubMed Central

    Zatorre, Robert J.

    2012-01-01

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

  9. 48 CFR 732.406-71 - Circumstances for use of an LOC.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Circumstances for use of an LOC. 732.406-71 Section 732.406-71 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL DEVELOPMENT GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING Advance Payments 732.406-71 Circumstances for use of an LOC. An LOC shall be...

  10. Roentgen Findings in Occipital Pole Tumors

    PubMed Central

    Bilodeau, Larry; Hanafee, William

    1967-01-01

    The arteriographic findings of occipital pole tumors consist of the following: 1. Anterior displacement and elevation of the middle cerebral group. 2. Accordioning of the anterior choroidal artery. 3. Anterior displacement of the lateral branch of the posterior choroidal artery. 4. Local stretching of vessels about the tumor. 5. Onion skinning of the pial vessels. 6. Anterior displacement of the vein of the occipital horn. 7. Greater displacement of the internal cerebral vein than of the anterior cerebral artery. Air studies require precise radiographic technique lest the subtle displacements of the occipital horn and trigone area be missed. ImagesFigure 1.Figure 2.Figure 3.Figure 4. PMID:6044288

  11. Increased expression of long noncoding RNAs LOC100652951 and LOC100506036 in T cells from patients with rheumatoid arthritis facilitates the inflammatory responses.

    PubMed

    Lu, Ming-Chi; Yu, Hui-Chun; Yu, Chia-Li; Huang, Hsien-Bin; Koo, Malcolm; Tung, Chien-Hsueh; Lai, Ning-Sheng

    2016-04-01

    The aim of this study was to evaluate whether the presence of aberrantly expressed lncRNAs could promote T cell inflammatory responses in patients with RA. The expression levels of 10 potential aberrantly expressed lncRNAs were evaluated in T cells from 39 patients with RA and 17 controls using real-time reverse transcription polymerase chain reaction. The aberrantly expressed lncRNAs were measured in Jurkat cells co-cultured with or without ionomycin and phorbol 12-myristate 13-acetate. Transfection studies using small interfering RNA (siRNA) were conducted for biological functions, and microarray analysis was performed to search for target genes of specific lncRNAs. We confirmed that the expression levels of LOC100652951 and LOC100506036 were higher in RA T cells compared with controls. RA patients treated with biologic agents had lower expression levels of LOC100652951, and female RA patients had lower LOC100506036 expression levels after multivariate analysis. After activation, the expression levels of LOC100506036, but not LOC100652951, increased in Jurkat cells. Transfection of siRNA targeting LOC100506036 inhibited interferon gamma production and the expression of nuclear factor of activated T cells in activated Jurkat cells. After the microarray analysis with validation, inhibition of LOC100506036 expression by siRNA leaded to the decreased expression of sphingomyelin phosphodiesterase 1 (SMPD1). In conclusion, the expression levels of LOC100652951 and LOC100506036 were increased in RA T cells. Treatment with biologic agents could lower the expression of LOC100652951 in RA T cells. LOC100506036 could regulate the expression of SMPD1 and NFAT1 and could contribute to the inflammatory responses in RA. PMID:26616293

  12. 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

  13. 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

  14. Early processing in the human lateral occipital complex is highly responsive to illusory contours but not to salient regions.

    PubMed

    Shpaner, Marina; Murray, Micah M; Foxe, John J

    2009-11-01

    Human electrophysiological studies support a model whereby sensitivity to so-called illusory contour stimuli is first seen within the lateral occipital complex. A challenge to this model posits that the lateral occipital complex is a general site for crude region-based segmentation, based on findings of equivalent hemodynamic activations in the lateral occipital complex to illusory contour and so-called salient region stimuli, a stimulus class that lacks the classic bounding contours of illusory contours. Using high-density electrical mapping of visual evoked potentials, we show that early lateral occipital cortex activity is substantially stronger to illusory contour than to salient region stimuli, whereas later lateral occipital complex activity is stronger to salient region than to illusory contour stimuli. Our results suggest that equivalent hemodynamic activity to illusory contour and salient region stimuli probably reflects temporally integrated responses, a result of the poor temporal resolution of hemodynamic imaging. The temporal precision of visual evoked potentials is critical for establishing viable models of completion processes and visual scene analysis. We propose that crude spatial segmentation analyses, which are insensitive to illusory contours, occur first within dorsal visual regions, not the lateral occipital complex, and that initial illusory contour sensitivity is a function of the lateral occipital complex. PMID:19895562

  15. 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

  16. 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

  17. Hypoplastic occipital condyle and third occipital condyle: review of their dysembryology.

    PubMed

    Tubbs, R Shane; Lingo, Patrick Ryan; Mortazavi, Martin M; Cohen-Gadol, Aaron A

    2013-11-01

    Disruption or embryologic derailment of the normal bony architecture of the craniovertebral junction (CVJ) may result in symptoms. As studies of the embryology and pathology of hypoplasia of the occipital condyles and third occipital condyles are lacking in the literature, the present review was performed. Standard search engines were accessed and queried for publications regarding hypoplastic occipital condyles and third occipital condyles. The literature supports the notion that occipital condyle hypoplasia and a third occipital condyle are due to malformation or persistence of the proatlas, respectively. The Pax-1 gene is most likely involved in this process. Clinically, condylar hypoplasia may narrow the foramen magnum and lead to lateral medullary compression. Additionally, this maldevelopment can result in transient vertebral artery compression secondary to posterior subluxation of the occiput. Third occipital condyles have been associated with cervical canal stenosis, hypoplasia of the dens, transverse ligament laxity, and atlanto-axial instability causing acute and chronic spinal cord compression. Treatment goals are focused on craniovertebral stability. A better understanding of the embryology and pathology related to CVJ anomalies is useful to the clinician treating patients presenting with these entities. PMID:23338989

  18. [Dependence of bioelectrical activity in occipital and frontal lobes and of the function of visual pathways from blood and oxygen supply].

    PubMed

    Khatsukov, V Kh; Kolchinskaia, A Z

    2000-01-01

    The dependence of occipital and frontal lobes of the brain cortex bioelectrical activity and function from blood and oxygen supply was investigated in 626 minopic and 80 children and teenagers with normal vision. Myopia was found a natural model of blood and oxygen deprivation, of decrease of bioelectrical activity of frontal and partially occipital lobes, especially. The decrease of alpha-rythme index and alpha-waves amplitude was found on EEG of occipital lobes. Adaptation to hypoxia in the course of interval hypoxic training and the course of osteoreflex stimulation were proved to be reliable means for improving blood and oxygen supply of occipital and frontal lobes of the brain cortex, which was followed by normalization of EEG and vision: the sharpness of vision rose to 1.0-0.9 in 80% of children and in 60% of teenagers. PMID:11424563

  19. Neuralgias of the Head: Occipital Neuralgia

    PubMed Central

    2016-01-01

    Occipital neuralgia is defined by the International Headache Society as paroxysmal shooting or stabbing pain in the dermatomes of the greater or lesser occipital nerve. Various treatment methods exist, from medical treatment to open surgical procedures. Local injection with corticosteroid can improve symptoms, though generally only temporarily. More invasive procedures can be considered for cases that do not respond adequately to medical therapies or repeated injections. Radiofrequency lesioning of the greater occipital nerve can relieve symptoms, but there is a tendency for the pain to recur during follow-up. There also remains a substantial group of intractable patients that do not benefit from local injections and conventional procedures. Moreover, treatment of occipital neuralgia is sometimes challenging. More invasive procedures, such as C2 gangliotomy, C2 ganglionectomy, C2 to C3 rhizotomy, C2 to C3 root decompression, neurectomy, and neurolysis with or without sectioning of the inferior oblique muscle, are now rarely performed for medically refractory patients. Recently, a few reports have described positive results following peripheral nerve stimulation of the greater or lesser occipital nerve. Although this procedure is less invasive, the significance of the results is hampered by the small sample size and the lack of long-term data. Clinicians should always remember that destructive procedures carry grave risks: once an anatomic structure is destroyed, it cannot be easily recovered, if at all, and with any destructive procedure there is always the risk of the development of painful neuroma or causalgia, conditions that may be even harder to control than the original complaint. PMID:27051229

  20. Neuralgias of the Head: Occipital Neuralgia.

    PubMed

    Choi, Il; Jeon, Sang Ryong

    2016-04-01

    Occipital neuralgia is defined by the International Headache Society as paroxysmal shooting or stabbing pain in the dermatomes of the greater or lesser occipital nerve. Various treatment methods exist, from medical treatment to open surgical procedures. Local injection with corticosteroid can improve symptoms, though generally only temporarily. More invasive procedures can be considered for cases that do not respond adequately to medical therapies or repeated injections. Radiofrequency lesioning of the greater occipital nerve can relieve symptoms, but there is a tendency for the pain to recur during follow-up. There also remains a substantial group of intractable patients that do not benefit from local injections and conventional procedures. Moreover, treatment of occipital neuralgia is sometimes challenging. More invasive procedures, such as C2 gangliotomy, C2 ganglionectomy, C2 to C3 rhizotomy, C2 to C3 root decompression, neurectomy, and neurolysis with or without sectioning of the inferior oblique muscle, are now rarely performed for medically refractory patients. Recently, a few reports have described positive results following peripheral nerve stimulation of the greater or lesser occipital nerve. Although this procedure is less invasive, the significance of the results is hampered by the small sample size and the lack of long-term data. Clinicians should always remember that destructive procedures carry grave risks: once an anatomic structure is destroyed, it cannot be easily recovered, if at all, and with any destructive procedure there is always the risk of the development of painful neuroma or causalgia, conditions that may be even harder to control than the original complaint. PMID:27051229

  1. Occipital lesions: a possible cost of cradleboards.

    PubMed

    Holliday, D Y

    1993-03-01

    This examination of a Mimbres-Mogollon pueblo skeletal sample reveals a surprising percentage of individuals with occipital lesions. Each lesion is located in the approximate center of the squama immediately superior to the external occipital protuberance. Notably, no child over the age of 1 year exhibits a lesion that would have been active at the time of death, but a number of older children and adults exhibit evidence of healed lesions in this same area on the occipital. The restricted nature of these lesions, in terms of both their locations and ages of those actively affected, suggests that the use of cradleboards may have been at least a contributing, if not initiatory, factor in their creation. Specifically, this study suggests that the pressure and friction of an infant's head against a cradleboard may have 1) produced ischemic ulcers, 2) produced the conditions favorable for bacterial infections such as impetigo or carbuncles, or 3) complicated the treatment of other infections appearing on the back of the scalp. PMID:8460652

  2. LncRNA loc285194 is a p53-regulated tumor suppressor

    PubMed Central

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

    2013-01-01

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

  3. Methylation-mediated downregulation of long noncoding RNA LOC100130476 in gastric cardia adenocarcinoma.

    PubMed

    Guo, Wei; Dong, Zhiming; Shi, Yabin; Liu, Shengnan; Liang, Jia; Guo, Yanli; Guo, Xin; Shen, Supeng; Wang, Guiying

    2016-06-01

    Accumulating evidences indicate that long non-coding RNAs (lncRNAs) play important roles in several biological processes and dysregulated lncRNAs are involved in different kinds of cancer and are associated with carcinogenesis, metastasis, and prognosis of cancer. The role of a new lncRNA LOC100130476 in gastric cardia adenocarcinoma (GCA) has remained unknown. The present study investigated the role and methylation status of LOC100130476 in the pathogenesis of GCA, and further evaluated the potential prognostic role of LOC100130476 in GCA. Significant downregulation of LOC100130476 was detected in SGC-7901 and BGC-823 cell lines and primary GCA tissues. Methylation frequency of LOC100130476 was gradually increased from exon 1 to exon 2 both in tumor tissues and corresponding normal tissues; however, methylation status of region 1 closing to the transcription start site was more tumor-specific among the three regions examined. The findings of the association between LOC100130476 expression, methylation and TNM stage, pathological differentiation, and GCA patients' survival further identified the role of LOC100130476 as a tumor suppressor gene. Furthermore, the hypermethylation of LOC100130476 was also detected in peripheral white blood cells of GCA cases. Thus, LOC100130476 may be act as a tumor suppressor gene in GCA carcinogenesis and aberrant methylation at the CpG sites near the transcription start site within exon 1 may be critical for gene silencing. In addition, aberrant methylation of LOC100130476 in peripheral white blood cells and GCA tissues may be used as a potential valuable biomarker in GCA diagnosis and prognosis. PMID:27189370

  4. 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

  5. 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

  6. 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

  7. 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.

  8. The occipital place area represents the local elements of scenes.

    PubMed

    Kamps, Frederik S; Julian, Joshua B; Kubilius, Jonas; Kanwisher, Nancy; Dilks, Daniel D

    2016-05-15

    Neuroimaging studies have identified three scene-selective regions in human cortex: parahippocampal place area (PPA), retrosplenial complex (RSC), and occipital place area (OPA). However, precisely what scene information each region represents is not clear, especially for the least studied, more posterior OPA. Here we hypothesized that OPA represents local elements of scenes within two independent, yet complementary scene descriptors: spatial boundary (i.e., the layout of external surfaces) and scene content (e.g., internal objects). If OPA processes the local elements of spatial boundary information, then it should respond to these local elements (e.g., walls) themselves, regardless of their spatial arrangement. Indeed, we found that OPA, but not PPA or RSC, responded similarly to images of intact rooms and these same rooms in which the surfaces were fractured and rearranged, disrupting the spatial boundary. Next, if OPA represents the local elements of scene content information, then it should respond more when more such local elements (e.g., furniture) are present. Indeed, we found that OPA, but not PPA or RSC, responded more to multiple than single pieces of furniture. Taken together, these findings reveal that OPA analyzes local scene elements - both in spatial boundary and scene content representation - while PPA and RSC represent global scene properties. PMID:26931815

  9. Surgical outcome in occipital lobe epilepsy: implications for pathophysiology.

    PubMed

    Aykut-Bingol, C; Bronen, R A; Kim, J H; Spencer, D D; Spencer, S S

    1998-07-01

    Medically refractory occipital lobe epilepsies are increasingly treated with surgery, but outcome and its relationship to etiology, pathological substrate, occipital lobe location, surgical approach, and electroclinical features have not been systematically investigated in a substantial group of patients. Thirty-five patients who underwent surgery for intractable occipital lobe seizures were retrospectively evaluated. Outcome and occipital lobe location were analyzed with respect to surgical procedure, pathology, clinical seizure characteristics, seizure onset and termination locations, and localization of interictal spikes. Most patients had developmental abnormalities (14) or tumors (13, all gliomas). Developmental abnormalities consisted of focal cortical dysplasia (5), heterotopia (2), hamartoma (3), cortical duplication (1), polymicrogyria (1), Sturge-Weber syndrome (1), and tuberous sclerosis (1). There was 1 patient with a vascular abnormality, 1 with chronic inflammatory changes, 4 with gliosis, 1 with cerebral ossification, and 1 with normal pathology. Developmental abnormalities had significantly worse outcome (45% excellent/good) than tumors (85% excellent/good). In the developmental group, low-grade focal cortical dysplasias had better outcome than heterotopia and hamartoma regardless of type of surgical procedure. Pathological groups did not significantly differ with respect to location within the occipital lobe (overall medial [50%] or lateral [38%]); clinical seizure characteristics referable to specific lobe (occipital [14%], temporal [34%], frontal [23%], more than one type [29%]); electroencephalographic localization (to occipital [17%], temporal [27%], or other/multifocal locations [56%]); or intracranial ictal onset or termination location. Electroclinical variables were also unrelated to the occipital lobe location of abnormality. Surgical outcome was not predicted by surgical approach (lesion excision with margins or lobectomy). The main pathological substrates of uncontrolled occipital lobe epilepsy are gliomas and developmental abnormalities. Whereas resection of occipital lobe tumors associated with chronic epilepsy produces nearly uniform seizure control, outcome after resection of occipital lobe developmental abnormalities is less uniform. PMID:9667593

  10. Cloning and sequence analysis of the LOC339524 gene in Sprague-Dawley rats.

    PubMed

    Long, Z H; Li, H; Chen, F; Zou, L Y

    2015-01-01

    We cloned the LOC339524 gene in Sprague-Dawley (SD) rats and analyzed the structure and function of the protein encoded by it. Based on the known human LOC339524 gene sequences, the full-length coding sequence of the LOC339524 gene in SD rats was cloned and amplified by the polymerase chain reaction using the complementary DNA of SD rats as a template. Bioinformatics analysis showed that the length of the cloned LOC339524 gene (GenBank accession No. KM224520) was 831 bp and it encoded a deduced protein of 276 amino acids. Sequence analysis revealed that the coded protein was identical to that produced in humans and its functional domain was located in the 138-236 amino acid fragments, a proline-rich region. Our results suggest that the encoded protein may be a significant regulator of the inflammatory response and may provide sufficient information to justify an in-depth investigation of the role of the LOC339524 gene. PMID:26681003

  11. Occipital nerve stimulation in primary headache syndromes

    PubMed Central

    Lambru, Giorgio

    2012-01-01

    Chronic daily headache is a major worldwide health problem that affects 3–5% of the population and results in substantial disability. Advances in the management of headache disorders have meant that a substantial proportion of patients can be effectively treated with medical treatments. However, a significant minority of these patients are intractable to conventional medical treatments. Occipital nerve stimulation (ONS) is emerging as a promising treatment for patients with medically intractable, highly disabling chronic headache disorders, including migraine, cluster headache and other less common headache syndromes. Open-label studies have suggested that this treatment modality is effective and recent controlled trial data are also encouraging. The procedure is performed using several technical variations that have been reviewed along with the complications, which are usually minor and tolerable. The mechanism of action is poorly understood, though recent data suggest that ONS could restore the balance within the impaired central pain system through slow neuromodulatory processes in the pain neuromatrix. While the available data are very encouraging, the ultimate confirmation of the utility of a new therapeutic modality should come from controlled trials before widespread use can be advocated; more controlled data are still needed to properly assess the role of ONS in the management of medically intractable headache disorders. Future studies also need to address the variables that are predictors of response, including clinical phenotypes, surgical techniques and stimulation parameters. PMID:22276076

  12. Occipital neuromodulation for refractory headache in the Chiari malformation population.

    PubMed

    Vadivelu, Sudhakar; Bolognese, Paolo; Milhorat, Thomas H; Mogilner, Alon Y

    2011-01-01

    Chronic occipital and suboccipital headache is a common symptom in patients with Chiari I malformation (CMI). These headaches may persist despite appropriate surgical treatment of the underlying pathology via suboccipital decompression, duraplasty and related procedures. Occipital stimulation has been shown to be effective in the treatment of a variety of occipital headache/pain syndromes. We present our series of 18 patients with CMI and persistent occipital headaches who underwent occipital neurostimulator trials and, following successful trials, permanent stimulator placement. Seventy-two percent (13/18) of patients had a successful stimulator trial and proceeded to permanent implant. Of those implanted, 11/13 (85%) reported continued pain relief at a mean follow-up of 23 months. Device-related complications requiring additional surgeries occurred in 31% of patients. Occipital neuromodulation may provide significant long-term pain relief in selected CMI patients with persistent occipital pain. Larger and longer-term studies are needed to further define appropriate patient selection criteria as well as to refine the surgical technique to minimize device-related complications. PMID:21422782

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

    NASA Astrophysics Data System (ADS)

    Zoller, Uri

    2002-02-01

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

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

    PubMed Central

    Zukić, Sanela; Sinanović, Osman; Hodžić, Renata; Mujagić, Svjetlana; Smajlović, 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

  15. Visual interhemispheric communication and callosal connections of the occipital lobes.

    PubMed

    Berlucchi, Giovanni

    2014-07-01

    Callosal connections of the occipital lobes, coursing in the splenium of the corpus callosum, have long been thought to be crucial for interactions between the cerebral hemispheres in vision in both experimental animals and humans. Yet the callosal connections of the temporal and parietal lobes appear to have more important roles than those of the occipital callosal connections in at least some high-order interhemispheric visual functions. The partial intermixing and overlap of temporal, parietal and occipital callosal connections within the splenium has made it difficult to attribute the effects of splenial pathological lesions or experimental sections to splenial components specifically related to select cortical areas. The present review describes some current contributions from the modern techniques for the tracking of commissural fibers within the living human brain to the tentative assignation of specific visual functions to specific callosal tracts, either occipital or extraoccipital. PMID:23489777

  16. Successful Treatment of Occipital Radiating Headache Using Pulsed Radiofrequency Therapy

    PubMed Central

    Lee, Sun Yeul; Jang, Dae Il; Noh, Chan

    2015-01-01

    Rheumatoid arthritis (RA) is a chronic inflammatory disease involving multiple joints. The cervical spine is often affected, and cases involving atlantoaxial joint can lead to instability. Anterior atlantoaxial subluxation in RA patients can lead to posterior neck pain or occipital headache because of compression of the C2 ganglion or nerve. Here, we report the successful treatment of a RA patient with occipital radiating headache using pulsed radiofrequency therapy at the C2 dorsal root ganglion. PMID:26279821

  17. Reconstruction of undersampled radial PatLoc imaging using total generalized variation.

    PubMed

    Knoll, Florian; Schultz, Gerrit; Bredies, Kristian; Gallichan, Daniel; Zaitsev, Maxim; Hennig, Jürgen; Stollberger, Rudolf

    2013-07-01

    In the case of radial imaging with nonlinear spatial encoding fields, a prominent star-shaped artifact has been observed if a spin distribution is encoded with an undersampled trajectory. This work presents a new iterative reconstruction method based on the total generalized variation, which reduces this artifact. For this approach, a sampling operator (as well as its adjoint) is needed that maps data from PatLoc k-space to the final image space. It is shown that this can be realized as a type-3 nonuniform fast Fourier transform, which is implemented by a combination of a type-1 and type-2 nonuniform fast Fourier transform. Using this operator, it is also possible to implement an iterative conjugate gradient SENSE based method for PatLoc reconstruction, which leads to a significant reduction of computation time in comparison to conventional PatLoc image reconstruction methods. Results from numerical simulations and in vivo PatLoc measurements with as few as 16 radial projections are presented, which demonstrate significant improvements in image quality with the total generalized variation-based approach. PMID:22847824

  18. Reconstruction of undersampled radial PatLoc imaging using Total Generalized Variation

    PubMed Central

    Knoll, Florian; Schultz, Gerrit; Bredies, Kristian; Gallichan, Daniel; Zaitsev, Maxim; Hennig, Jürgen; Stollberger, Rudolf

    2016-01-01

    In the case of radial imaging with nonlinear spatial encoding fields, a prominent star-shaped artifact has been observed if a spin distribution is encoded with an undersampled trajectory. This work presents a new iterative reconstruction method based on the total generalized variation (TGV), which reduces this artifact. For this approach, a sampling operator (as well as its adjoint) is needed that maps data from PatLoc k-space to the final image space. It is shown that this can be realized as a Type-3 non-uniform FFT, which is implemented by a combination of a Type-1 and Type-2 non-uniform FFT. Using this operator, it is also possible to implement an iterative conjugate gradient (CG) SENSE based method for PatLoc reconstruction, which leads to a significant reduction of computation time in comparison to conventional PatLoc image reconstruction methods. Results from numerical simulations and in-vivo PatLoc measurements with as few as 16 radial projections are presented, which demonstrate significant improvements in image quality with the TGV based approach. PMID:22847824

  19. 48 CFR 732.406-71 - Circumstances for use of an LOC.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... an LOC. 732.406-71 Section 732.406-71 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL... determined that an advance payment is necessary and appropriate in accordance with this subpart and the...,000; and (c) The Office of Financial Management, Cash Management and Payment Division (FM/CMP)...

  20. 48 CFR 732.406-71 - Circumstances for use of an LOC.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... an LOC. 732.406-71 Section 732.406-71 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL... determined that an advance payment is necessary and appropriate in accordance with this subpart and the...,000; and (c) The Office of Financial Management, Cash Management and Payment Division (FM/CMP)...

  1. 48 CFR 732.406-71 - Circumstances for use of an LOC.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... an LOC. 732.406-71 Section 732.406-71 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL... determined that an advance payment is necessary and appropriate in accordance with this subpart and the...,000; and (c) The Office of Financial Management, Cash Management and Payment Division (FM/CMP)...

  2. 48 CFR 732.406-71 - Circumstances for use of an LOC.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... an LOC. 732.406-71 Section 732.406-71 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL... determined that an advance payment is necessary and appropriate in accordance with this subpart and the...,000; and (c) The Office of Financial Management, Cash Management and Payment Division (FM/CMP)...

  3. 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…

  4. 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

  5. Early (N170/M170) Face-Sensitivity Despite Right Lateral Occipital Brain Damage in Acquired Prosopagnosia

    PubMed Central

    Prieto, Esther Alonso; Caharel, Stphanie; Henson, Richard; Rossion, Bruno

    2011-01-01

    Compared to objects, pictures of faces elicit a larger early electromagnetic response at occipito-temporal sites on the human scalp, with an onset of 130?ms and a peak at about 170?ms. This N170 face effect is larger in the right than the left hemisphere and has been associated with the early categorization of the stimulus as a face. Here we tested whether this effect can be observed in the absence of some of the visual areas showing a preferential response to faces as typically identified in neuroimaging. Event-related potentials were recorded in response to faces, cars, and their phase-scrambled versions in a well-known brain-damaged case of prosopagnosia (PS). Despite the patients right inferior occipital gyrus lesion encompassing the most posterior cortical area showing preferential response to faces (occipital face area), we identified an early face-sensitive component over the right occipito-temporal hemisphere of the patient that was identified as the N170. A second experiment supported this conclusion, showing the typical N170 increase of latency and amplitude in response to inverted faces. In contrast, there was no N170 in the left hemisphere, where PS has a lesion to the middle fusiform gyrus and shows no evidence of face-preferential response in neuroimaging (no left fusiform face area). These results were replicated by a magnetoencephalographic investigation of the patient, disclosing a M170 component only in the right hemisphere. These observations indicate that face-preferential activation in the inferior occipital cortex is not necessary to elicit early visual responses associated with face perception (N170/M170) on the human scalp. These results further suggest that when the right inferior occipital cortex is damaged, the integrity of the middle fusiform gyrus and/or the superior temporal sulcus two areas showing face-preferential responses in the patients right hemisphere might be necessary to generate the N170 effect. PMID:22275889

  6. Detection of G-Induced Loss of Consciousness (G-LOC) prognosis through EMG monitoring on gastrocnemius muscle in flight.

    PubMed

    Booyong Choi; Yongkyun Lee; Taehwan Cho; Hyojin Koo; Dongsoo Kim

    2015-08-01

    G-Induced Loss of Consciousness (G-LOC) is mainly caused by the sudden acceleration in the direction of +Gz axis from the fighter pilots, and is considered as an emergent situation of which fighter pilots are constantly aware. In order to resist against G-LOC, fighter pilots are subject to run Anti-G straining maneuver (AGSM), which includes L-1 respiration maneuvering and muscular contraction of the whole body. The purpose of this study is to create a G-LOC warning alarm prior to G-LOC by monitoring the Electromyogram (EMG) of the gastrocnemius muscle on the calf, which goes under constant muscular contraction during the AGSM process. EMG data was retrieved from pilots and pilot trainees of the Korean Air Force, during when subjects were under high G-trainings on a human centrifugal simulator. Out of the EMG features, integrated absolute value (IAV), reflecting muscle contraction, and waveform length (WL), reflecting muscle contraction and fatigue, have shown a rapid decay during the alarm phase, 3 seconds before G-LOC, compared to that of a normal phase withstanding G-force. Such results showed consistency amongst pilots and pilot trainees who were under G-LOC. Based on these findings, this study developed an algorithm which can detect G-LOC prognosis during flight, and at the same time, generate warning signals. The probability of G-LOC occurrence is detected through monitoring the decay trend and degree of the IVA and WL value of when the pilot initiates AGSM during sudden acceleration above 6G. Conclusively, this G-LOC prognosis detecting and warning system is a customized, real-time countermeasure which enhanced the accuracy of detecting G-LOC. PMID:26737905

  7. 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

  8. 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

  9. 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

  10. 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

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

    PubMed

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

    2014-01-01

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

  12. Symptomatic parieto-occipital epilepsy as sequela of perinatal asphyxia.

    PubMed

    Oguni, Hirokazu; Sugama, Michiko; Osawa, Makiko

    2008-05-01

    Perinatal hypoxic-ischemic encephalopathy in term infants has been well-documented as a cause of selective brain damage over the parasagittal brain regions in cases of partial asphyxia. We describe 10 patients (7 boys, 3 girls) who developed normally after perinatal asphyxia, and who later experienced parieto-occipital epilepsy. We retrospectively reviewed medical records, electroencephalograms, and neuroimaging findings. All patients had a history of perinatal asphyxia requiring intensive care. Subsequent developmental milestones were apparently normal. Seizures started at ages ranging from 10 to 168 months (mean, 72 months). The seizures comprised complex partial seizures with visual symptomatology in 5 cases, complex partial seizures without visual symptomatology in 4 cases, and focal motor seizures with secondary generalization in the remaining case. Brain magnetic resonance imaging demonstrated localized parieto-occipital lesions in 9 cases, and normal findings in the remaining one. Electroencephalograms revealed predominantly occipital foci in 8. In all patients, the epileptogenic foci involved either unilateral or bilateral parieto-occipital regions. Intelligence quotients and visuospatial cognitive functions were impaired in 7 patients. Seizures were finally controlled in only 4 patients. Symptomatic parieto-occipital epilepsy caused by mild perinatal hypoxic-ischemic encephalopathy is sometimes pharmaco-resistant and accompanied by mild cognitive and visuospatial impairments. PMID:18410851

  13. 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

  14. [Traumatic atlanto-occipital dislocation in a calf].

    PubMed

    Knubben-Schweizer, G; Friedrich, A; Ebert, U; Hördemann, M; Hagen, R; Nuss, K

    2012-01-01

    In a 7-week-old calf neurologic symptoms occurred after an accident in the feeding grid. The calf was alert but in left lateral recumbency. After having been placed on its right side it showed a sideward drift to the left. Following head movement, an asynchronous movement of the eyes could be observed. Lesions of the upper motor neuron system, N. vestibulocochlearis, Nn. oculomotorius, trochlearis and/or abducens as well as N. vagus were suspected. Radiological examination of the occipital region and cervical spine revealed an atlanto-occipital subluxation of the atlas. Based on all these findings, the diagnosis of traumatic atlanto-occipital dislocation was made and the calf was euthanized. The pathological findings confirmed this diagnosis. PMID:22331290

  15. Portable multi-immunosensing lab-on-a-chip (LOC) triggered by air bladder

    NASA Astrophysics Data System (ADS)

    Kang, Tae Ho; Park, Sin Wook; Lee, Jun Hwang; Yoon, Hyun C.; Yang, Sang Sik

    2007-12-01

    This paper presents a simple and reliable multi-immunosensing lab-on-a-chip detecting antibodies as multi-disease markers using electrochemical method suitable for a portable point-of-care system. Since multi-immunosensing LOCs are to be disposable and cheap, the complications associated with the liquid control need to be removed. The main complication arises from the active microfluidic part driven by the external electric power. In this paper, a multi-stacked PDMS LOC including PDMS passive valves is proposed. The sequential liquid driving by capillary attraction and the action of check valve provide a reliable immunosensing tool simply triggered by an air bladder push without an electrical power. The immunosensing-LOC with the size of "25mm × 20mm × 6 mm" is fabricated with PDMS using the replica molding and oxygen plasma bonding. The LOC consists of a PDMS valve, channel, and a glass substrate. The fluidic tests were performed using DI water. The liquids are controlled by two kinds of passive valve, one is capillary stop valve and the other is membrane type check valve. The capillary stop valve stops liquids using pressure barrier of expanded channel. The check valve stops the liquid triggered by an air bladder from flowing backward. The assembly of these two valves assures the well controlled liquid driving for the immunosensing. The model experiments were performed with anti-DNP antibody and anti-biotin antibody as target analytes. The antibodies conjugated with GOX are used as a signaling molecule for cyclic voltammetry. The different amplified signals show different target analyte affinities and make sure the multi-immunosensing.

  16. LOC387761 polymorphism is associated with type 2 diabetes in the Mexican population.

    PubMed

    Gutiérrez-Vidal, Roxana; Rodríguez-Trejo, Adriana; Canizales-Quinteros, Samuel; Herrera-Cornejo, Martín; Granados-Silvestre, Maria Angeles; Montúfar-Robles, Isela; Ortiz-López, María Guadalupe; Menjívar, Marta

    2011-01-01

    Worldwide researchers have invested time, effort, and money during the last years to find new genes associated with diabetes susceptibility, such as LOC387761, HHEX, EXT2, and SLC30A8. The aim of the present study was to evaluate whether single-nucleotide polymorphisms (SNPs) of these genes are associated with type 2 diabetes (T2D) and metabolic traits in the Mexican population. We also assessed these SNPs in Mexican indigenous groups to identify a possible inherited susceptibility. Seven SNPs were analyzed in 789 Mexicans (234 control subjects, 455 type 2 diabetic patients, and 100 of indigenous origin), using the KASPar assay (KBioscience Company). Analysis of the data showed an association of the LOC387761 SNP rs7480010 with T2D (p = 0.019). The risk allele A of rs7480010 increased body mass index in diabetic patients (p = 0.01). In addition, there was no association between T2D and the SNPs of HHEX, EXT2, and SLC30A8. Our findings suggest that the SNP rs7480010 (LOC387761) can contribute to a failure in insulin secretion, thus increasing the susceptibility to T2D in Mexicans. PMID:21198374

  17. Grievous temporal and occipital injury caused by a bear attack.

    PubMed

    Prasad, Sampath Chandra; 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

  18. 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

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

    PubMed Central

    2013-01-01

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

  20. Neurochemical changes in the pericalcarine cortex in congenital blindness attributable to bilateral anophthalmia.

    PubMed

    Coullon, Gaelle S L; Emir, Uzay E; Fine, Ione; Watkins, Kate E; Bridge, Holly

    2015-09-01

    Congenital blindness leads to large-scale functional and structural reorganization in the occipital cortex, but relatively little is known about the neurochemical changes underlying this cross-modal plasticity. To investigate the effect of complete and early visual deafferentation on the concentration of metabolites in the pericalcarine cortex, (1)H magnetic resonance spectroscopy was performed in 14 sighted subjects and 5 subjects with bilateral anophthalmia, a condition in which both eyes fail to develop. In the pericalcarine cortex, where primary visual cortex is normally located, the proportion of gray matter was significantly greater, and levels of choline, glutamate, glutamine, myo-inositol, and total creatine were elevated in anophthalmic relative to sighted subjects. Anophthalmia had no effect on the structure or neurochemistry of a sensorimotor cortex control region. More gray matter, combined with high levels of choline and myo-inositol, resembles the profile of the cortex at birth and suggests that the lack of visual input from the eyes might have delayed or arrested the maturation of this cortical region. High levels of choline and glutamate/glutamine are consistent with enhanced excitatory circuits in the anophthalmic occipital cortex, which could reflect a shift toward enhanced plasticity or sensitivity that could in turn mediate or unmask cross-modal responses. Finally, it is possible that the change in function of the occipital cortex results in biochemical profiles that resemble those of auditory, language, or somatosensory cortex. PMID:26180125

  1. dLocAuth: a dynamic multifactor authentication scheme for mCommerce applications using independent location-based obfuscation

    NASA Astrophysics Data System (ADS)

    Kuseler, Torben; Lami, Ihsan A.

    2012-06-01

    This paper proposes a new technique to obfuscate an authentication-challenge program (named LocProg) using randomly generated data together with a client's current location in real-time. LocProg can be used to enable any handsetapplication on mobile-devices (e.g. mCommerce on Smartphones) that requires authentication with a remote authenticator (e.g. bank). The motivation of this novel technique is to a) enhance the security against replay attacks, which is currently based on using real-time nonce(s), and b) add a new security factor, which is location verified by two independent sources, to challenge / response methods for authentication. To assure a secure-live transaction, thus reducing the possibility of replay and other remote attacks, the authors have devised a novel technique to obtain the client's location from two independent sources of GPS on the client's side and the cellular network on authenticator's side. The algorithm of LocProg is based on obfuscating "random elements plus a client's data" with a location-based key, generated on the bank side. LocProg is then sent to the client and is designed so it will automatically integrate into the target application on the client's handset. The client can then de-obfuscate LocProg if s/he is within a certain range around the location calculated by the bank and if the correct personal data is supplied. LocProg also has features to protect against trial/error attacks. Analysis of LocAuth's security (trust, threat and system models) and trials based on a prototype implementation (on Android platform) prove the viability and novelty of LocAuth.

  2. Spatial Cognition: Finding the Boundary in the Occipital Place Area.

    PubMed

    Spiers, Hugo J

    2016-04-25

    A new study using transcranial magnetic stimulation and a virtual reality navigation task has shown that we need the brain's occipital place area to accurately remember where objects are located in relation to boundaries, but not in relation to landmarks. PMID:27115688

  3. Anatomic basis for localized occipital thinning: a normal anatomic variant

    SciTech Connect

    Haden, M.A.; Keats, T.E.

    1982-06-01

    The radiographic evidence presented in this case confirms that the asymptomatic, incidentally found occipital radiolucencies previously described by Keats are not a problem in differential diagnosis of inner table erosion. The entity appears to be a developmental variant with typical features and occurring in a characteristic location.

  4. 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

  5. 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…

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

    PubMed Central

    Holečková, Nela; Molle, Virginie; Buriánková, Karolína; Benada, Oldřich; Kofroňová, Olga; Ulrych, Aleš; Branny, Pavel

    2014-01-01

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

  7. 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

  8. Role of Loc1p in assembly and reorganization of nuclear ASH1 messenger ribonucleoprotein particles in yeast

    PubMed Central

    Niedner, Annika; Müller, Marisa; Moorthy, Balaji T.; Jansen, Ralf-Peter; Niessing, Dierk

    2013-01-01

    Directional transport of mRNA is a universal feature in eukaryotes, requiring the assembly of motor-dependent RNA-transport particles. The cytoplasmic transport of mRNAs is preceded by the nuclear assembly of pre-messenger ribonucleoprotein particles (mRNPs). In budding yeast, the asymmetric synthesis of HO 1 (ASH1) pre-mRNP originates already cotranscriptionally and passes through the nucleolus before its nuclear export. The nucleolar localization of ASH1 mRNA protein 1 (Loc1p) is required for efficient ASH1 mRNA localization. Immunoprecipitation experiments have revealed that Loc1p forms cocomplexes with other components of the ASH1 transport complex. However, it remains unclear how Loc1p is recruited into this mRNP and why Loc1p is important for ASH1 mRNA localization. Here we demonstrate that Loc1p undergoes a direct and specific interaction with the ASH1 mRNA-binding Swi5p-dependent HO expression protein 2 (She2p). This cocomplex shows higher affinity and specificity for RNA bearing localization elements than the individual proteins. It also stabilizes the otherwise transient binding of She2p to ASH1 mRNA, suggesting that cooperative mRNA binding of Loc1p with She2p is the required nuclear function of Loc1p for ASH1 mRNA localization. After nuclear export, myosin-bound She3p joins the ASH1 mRNP to form a highly specific cocomplex with She2p and ASH1 mRNA. Because Loc1p is found only in the nucleus, it must be removed from the complex directly before or after export. In vitro and in vivo experiments indicate that the synergistic interaction of She2p and She3p displaces Loc1p from the ASH1 complex, allowing free Loc1p to rapidly reenter the nucle(ol)us. Together these findings suggest an ordered process of nuclear assembly and reorganization for the maturation of localizing ASH1 mRNPs. PMID:24324176

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

    ERIC Educational Resources Information Center

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

    2011-01-01

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

  10. LOC283731 promoter hypermethylation prognosticates survival after radiochemotherapy in IDH1 wild-type glioblastoma patients.

    PubMed

    Mock, Andreas; Geisenberger, Christoph; Orlik, Christian; Warta, Rolf; Schwager, Christian; Jungk, Christine; Dutruel, Céline; Geiselhart, Lea; Weichenhan, Dieter; Zucknick, Manuela; Nied, Ann-Katrin; Friauf, Sara; Exner, Janina; Capper, David; Hartmann, Christian; Lahrmann, Bernd; Grabe, Niels; Debus, Jürgen; von Deimling, Andreas; Popanda, Odilia; Plass, Christoph; Unterberg, Andreas; Abdollahi, Amir; Schmezer, Peter; Herold-Mende, Christel

    2016-07-15

    MGMT promoter methylation status is currently the only established molecular prognosticator in IDH wild-type glioblastoma multiforme (GBM). Therefore, we aimed to discover novel therapy-associated epigenetic biomarkers. After enrichment for hypermethylated fractions using methyl-CpG-immunoprecipitation (MCIp), we performed global DNA methylation profiling for 14 long-term (LTS; >36 months) and 15 short-term (STS; 6-10 months) surviving GBM patients. Even after exclusion of the G-CIMP phenotype, we observed marked differences between the LTS and STS methylome. A total of 1,247 probes in 706 genes were hypermethylated in LTS and 463 probes in 305 genes were found to be hypermethylated in STS patients (p values < 0.05, log2 fold change ± 0.5). We identified 13 differentially methylated regions (DMRs) with a minimum of four differentially methylated probes per gene. Indeed, we were able to validate a subset of these DMRs through a second, independent method (MassARRAY) in our LTS/STS training set (ADCY1, GPC3, LOC283731/ISLR2). These DMRs were further assessed for their prognostic capability in an independent validation cohort (n = 62) of non-G-CIMP GBMs from the TCGA. Hypermethylation of multiple CpGs mapping to the promoter region of LOC283731 correlated with improved patient outcome (p = 0.03). The prognostic performance of LOC283731 promoter hypermethylation was confirmed in a third independent study cohort (n = 89), and was independent of gender, performance (KPS) and MGMT status (p = 0.0485, HR = 0.63). Intriguingly, the prediction was most pronounced in younger GBM patients (<60 years). In conclusion, we provide compelling evidence that promoter methylation status of this novel gene is a prognostic biomarker in IDH1 wild-type/non-G-CIMP GBMs. PMID:26934681

  11. LACEwING: LocAting Constituent mEmbers In Nearby Groups

    NASA Astrophysics Data System (ADS)

    Riedel, Adric R.

    2016-01-01

    LACEwING (LocAting Constituent mEmbers In Nearby Groups) uses the kinematics (positions and motions) of stars to determine if they are members of one of 10 nearby young moving groups or 4 nearby open clusters within 100 parsecs. It is written for Python 2.7 and depends upon Numpy, Scipy, and Astropy (ascl:1304.002) modules. LACEwING can be used as a stand-alone code or as a module in other code. Additional python programs are present in the repository for the purpose of recalibrating the code and producing other analyses, including a traceback analysis.

  12. Object Working Memory Performance Depends on Microstructure of the Frontal-Occipital Fasciculus

    PubMed Central

    Walsh, Megan; Montojo, Caroline A.; Sheu, Yi-Shin; Marchette, Steven A.; Harrison, Daniel M.; Newsome, Scott D.; Zhou, Feng; Shelton, Amy L.

    2011-01-01

    Abstract Re-entrant circuits involving communication between the frontal cortex and other brain areas have been hypothesized to be necessary for maintaining the sustained patterns of neural activity that represent information in working memory, but evidence has so far been indirect. If working memory maintenance indeed depends on such temporally precise and robust long-distance communication, then performance on a delayed recognition task should be highly dependent on the microstructural integrity of white-matter tracts connecting sensory areas with prefrontal cortex. This study explored the effect of variations in white-matter microstructure on working memory performance in two separate groups of participants: patients with multiple sclerosis and age- and sex-matched healthy adults. Functional magnetic resonance imaging was performed to reveal cortical regions involved in spatial and object working memory, which, in turn, were used to define specific frontal to extrastriate white-matter tracts of interest via diffusion tensor tractography. After factoring out variance due to age and the microstructure of a control tract (the corticospinal tract), the number of errors produced in the object working memory task was specifically related to the microstructure of the inferior frontal-occipital fasciculus. This result held for both groups, independently, providing a within-study replication with two different types of white-matter structural variability: multiple sclerosis–related damage and normal variation. The results demonstrate the importance of interactions between specific regions of the prefrontal cortex and sensory cortices for a nonspatial working memory task that preferentially activates those regions. PMID:22432421

  13. Object working memory performance depends on microstructure of the frontal-occipital fasciculus.

    PubMed

    Walsh, Megan; Montojo, Caroline A; Sheu, Yi-Shin; Marchette, Steven A; Harrison, Daniel M; Newsome, Scott D; Zhou, Feng; Shelton, Amy L; Courtney, Susan M

    2011-01-01

    Re-entrant circuits involving communication between the frontal cortex and other brain areas have been hypothesized to be necessary for maintaining the sustained patterns of neural activity that represent information in working memory, but evidence has so far been indirect. If working memory maintenance indeed depends on such temporally precise and robust long-distance communication, then performance on a delayed recognition task should be highly dependent on the microstructural integrity of white-matter tracts connecting sensory areas with prefrontal cortex. This study explored the effect of variations in white-matter microstructure on working memory performance in two separate groups of participants: patients with multiple sclerosis and age- and sex-matched healthy adults. Functional magnetic resonance imaging was performed to reveal cortical regions involved in spatial and object working memory, which, in turn, were used to define specific frontal to extrastriate white-matter tracts of interest via diffusion tensor tractography. After factoring out variance due to age and the microstructure of a control tract (the corticospinal tract), the number of errors produced in the object working memory task was specifically related to the microstructure of the inferior frontal-occipital fasciculus. This result held for both groups, independently, providing a within-study replication with two different types of white-matter structural variability: multiple sclerosis-related damage and normal variation. The results demonstrate the importance of interactions between specific regions of the prefrontal cortex and sensory cortices for a nonspatial working memory task that preferentially activates those regions. PMID:22432421

  14. The problem of macular sparing after unilateral occipital lesions.

    PubMed

    Sugishita, M; Hemmi, I; Sakuma, I; Beppu, H; Shiokawa, Y

    1993-11-01

    Whether or not unilateral occipital damage produces sparing of central vision, namely macular sparing, is controversial. We tested two subjects with left occipital lesions by means of fundus perimetry combined with fundus image analysis. This method made it possible to measure the distance of the stimulus projected on the retina from the foveal centre defined as the centre of the foveal reflex. The results indicated that macular sparing, if it exists, must be less than 0.4 degree wide. Two of the four eyes during the stimulus presentation often but not always showed eccentric fixation of a small magnitude, whose mean was less than 0.6 degree from the foveal centre in the right hemiretina. PMID:8138815

  15. Prenatal Diagnosis of Tectocerebellar Dysraphia with Occipital Encephalocele

    PubMed Central

    Sanhal, Cem Y; Tokmak, Aytekin; Müftüoglu, Kamil H; Danisman, Nuri

    2015-01-01

    Tectocerebellar dysraphia (TCD) is an extremely rare disorder and comprises the congenital abnormalities including occipital encephalocele, aplasia and/or hypoplasia of cerebellar vermis and deformity of tectum. Only few reported cases of this entity are there in the literature. However, the diagnosis in each of the previous cases had been made after birth. We herein describe the first reported case of prenatal diagnosis for TCD in a Turkish woman. PMID:26816952

  16. Occipital injections for trigemino-autonomic cephalalgias: evidence and uncertainties.

    PubMed

    Leroux, Elizabeth; Ducros, Anne

    2013-04-01

    Cluster headache is a debilitating disorder. Oral prophylactic treatments may act with a significant delay, cause side effects, or fail to control the attacks. Injections targeting the occipital nerve have raised interest for the management of CH. Their efficacy is thought to result from the anatomical convergence of trigeminal and cervical afferents in the trigeminal nucleus caudalis. Efficacy and safety of occipital injections are now documented by 2 randomized controlled trials and several case series, though the optimal technique and substance to be injected are still subject to discussion due to varied approaches in the published studies. The evidence supports the use of injected steroids, with or without the addition of an anesthetic. Side effects of local pain are common, but unlikely to be severe. Systemic effects related to steroid absorption are reported but infrequent. Occipital injections provide a rapid benefit on the frequency of attacks and can be used as an adjunct to an oral prophylactic for a quicker improvement. Whether or not this approach can be used without any oral prophylaxis is still to be determined. The technique is easy to master, has a low cost, and should be learned by physicians involved in CH management. PMID:23443504

  17. Metabolic Changes in Occipital Lobe Epilepsy with Automatisms

    PubMed Central

    Wong, Chong H.; Mohamed, Armin; Wen, Lingfeng; Eberl, Stefan; Somerville, Ernest; Fulham, Michael; Bleasel, Andrew F.

    2014-01-01

    Purpose: Some studies suggest that the pattern of glucose hypometabolism relates not only to the ictal-onset zone but also reflects seizure propagation. We investigated metabolic changes in patients with occipital lobe epilepsy (OLE) that may reflect propagation of ictal discharge during seizures with automatisms. Methods: Fifteen patients who had undergone epilepsy surgery for intractable OLE and had undergone interictal Fluorine-18-fluorodeoxyglucose positron-emission tomography (18F-FDG-PET) between 1994 and 2004 were divided into two groups (with and without automatisms during seizure). Significant regions of hypometabolism were identified by comparing 18F-FDG-PET results from each group with 16 healthy controls by using statistical parametric mapping. Key Findings: Significant hypometabolism was confined largely to the epileptogenic occipital lobe in the patient group without automatisms. In patients with automatisms, glucose hypometabolism extended from the epileptogenic occipital lobe into the ipsilateral temporal lobe. Significance: We identified a distinctive hypometabolic pattern that was specific for OLE patients with automatisms during a seizure. This finding supports the postulate that seizure propagation is a cause of glucose hypometabolism beyond the region of seizure onset. PMID:25101053

  18. Feedback of visual object information to foveal retinotopic cortex.

    PubMed

    Williams, Mark A; Baker, Chris I; Op de Beeck, Hans P; Shim, Won Mok; Dang, Sabin; Triantafyllou, Christina; Kanwisher, Nancy

    2008-12-01

    The mammalian visual system contains an extensive web of feedback connections projecting from higher cortical areas to lower areas, including primary visual cortex. Although multiple theories have been proposed, the role of these connections in perceptual processing is not understood. We found that the pattern of functional magnetic resonance imaging response in human foveal retinotopic cortex contained information about objects presented in the periphery, far away from the fovea, which has not been predicted by prior theories of feedback. This information was position invariant, correlated with perceptual discrimination accuracy and was found only in foveal, but not peripheral, retinotopic cortex. Our data cannot be explained by differential eye movements, activation from the fixation cross, or spillover activation from peripheral retinotopic cortex or from lateral occipital complex. Instead, our findings indicate that position-invariant object information from higher cortical areas is fed back to foveal retinotopic cortex, enhancing task performance. PMID:18978780

  19. LocTree2 predicts localization for all domains of life

    PubMed Central

    Goldberg, Tatyana; Hamp, Tobias; Rost, Burkhard

    2012-01-01

    Motivation: Subcellular localization is one aspect of protein function. Despite advances in high-throughput imaging, localization maps remain incomplete. Several methods accurately predict localization, but many challenges remain to be tackled. Results: In this study, we introduced a framework to predict localization in life's three domains, including globular and membrane proteins (3 classes for archaea; 6 for bacteria and 18 for eukaryota). The resulting method, LocTree2, works well even for protein fragments. It uses a hierarchical system of support vector machines that imitates the cascading mechanism of cellular sorting. The method reaches high levels of sustained performance (eukaryota: Q18=65%, bacteria: Q6=84%). LocTree2 also accurately distinguishes membrane and non-membrane proteins. In our hands, it compared favorably with top methods when tested on new data. Availability: Online through PredictProtein (predictprotein.org); as standalone version at http://www.rostlab.org/services/loctree2. Contact: localization@rostlab.org Supplementary Information: Supplementary data are available at Bioinformatics online. PMID:22962467

  20. Gyrokinetic Simulations of Diluted Plasmas in the LOC regime in Alcator C-Mod

    NASA Astrophysics Data System (ADS)

    Porkolab, M.; Ennever, P.; Reinke, M. L.; Rice, J.; Rost, C.; Tsujii, N.; Davis, E.; Ernst, D.; Fiore, C.; Greenwald, M.; Hubbard, A.; Hughes, J.; Marmar, E.; Candy, J.; Staebler, G. M.; Waltz, R.

    2012-10-01

    Previous investigations of ITG and TEM/ETG turbulence using the reduced gyro-landau fluid code TGLF, and gyrokinetic code GYRO have predicted that in the linear ohmic confinement (LOC) regime in Alcator C-Mod the dilution of the main D ion species by low-Z impurities reduces the ion transport to experimentally observed levels. This analysis assumed an average impurity ion charge Zi= 8. Recent spectroscopic measurements of the impurity ion species in the LOC regime in C-Mod have shown that the average Zi is approximately 9, which at the measured Zeff values (2-4) results in a significant dilution (>10%) of the majority D ion species. By puffing in nitrogen while using a cryopump to keep the density constant, new experiments enabled us to lower Zi to values near 8, thus further increasing dilution. To account for the sensitivity of the turbulent transport on the density (Lne) and temperature (LTe) gradient scale lengths, recently we used TGYRO to improve the agreement between theory and the measurements. The results of such simulations will be presented.

  1. Assessment of Brain Damage and Plasticity in the Visual System Due to Early Occipital Lesion: Comparison of FDG-PET with Diffusion MRI Tractography

    PubMed Central

    Jeong, Jeong-won; Tiwari, Vijay N.; Shin, Joseph; Chugani, Harry T.; Juhász, Csaba

    2015-01-01

    Purpose To determine the relation between glucose metabolic changes of the primary visual cortex, structural abnormalities of the corresponding visual tracts, and visual symptoms in children with Sturge-Weber syndrome (SWS). Materials and Methods In 10 children with unilateral SWS (ages 1.5–5.5 years), a region-of-interest analysis was applied in the bilateral medial occipital cortex on positron emission tomography (PET) and used to track diffusion-weighted imaging (DWI) streamlines corresponding to the central visual pathway. Normalized streamline volumes of individual SWS patients were compared with values from age-matched control groups as well as correlated with normalized glucose uptakes and visual field deficit. Results Lower glucose uptake and lower corresponding streamline volumes were detected in the affected occipital lobe in 9/10 patients, as compared to the contralateral side. Seven of these 9 patients had visual field deficit and normal or decreased streamline volumes on the unaffected side. The two other children had no visual symptoms and showed high contralateral visual streamline volumes. There was a positive correlation between the normalized ratios on DWI and PET, indicating that lower glucose metabolism was associated with lower streamline volume in the affected hemisphere (R = 0.70, P = 0.024). Conclusion We demonstrated that 18F-flurodeoxyglucose (FDG)-PET combined with DWI tractography can detect both brain damage on the side of the lesion and contralateral plasticity in children with early occipital lesions. PMID:24391057

  2. Endovascular Internal Trapping of Ruptured Occipital Artery Pseudoaneurysm Associated with Occipital-Internal Jugular Vein Fistula in Neurofibromatosis Type 1.

    PubMed

    Imahori, Taichiro; Fujita, Atsushi; Hosoda, Kohkichi; Kohmura, Eiji

    2016-05-01

    Spontaneous cervical extradural pseudoaneurysms or arteriovenous fistulas (AVFs) are rare vascular diseases. We report a case of ruptured occipital artery (OA) pseudoaneurysm associated with occipital-internal jugular vein (IJV) fistula in neurofibromatosis type 1. Endovascular internal trapping via the OA was attempted; however, the distal entry of the OA could not be accessed because of the high shunt flow and tortuosity of the OA. The distal part of the OA was obliterated with coil via a transvenous approach through the IJV and pseudoaneurysm. The proximal entry of the OA was obliterated with coil and glue under proximal flow control with a balloon, and the fistula was successfully obliterated without placement of coils in the pseudoaneurysm. When ordinary internal trapping via a transarterial approach is not possible, the transvenous approach should be considered as an alternative for AVF associated with an aneurysmal component. PMID:26971039

  3. Occipital cortical thickness in very low birth weight born adolescents predicts altered neural specialization of visual semantic category related neural networks.

    PubMed

    Klaver, Peter; Latal, Beatrice; Martin, Ernst

    2015-01-01

    Very low birth weight (VLBW) premature born infants have a high risk to develop visual perceptual and learning deficits as well as widespread functional and structural brain abnormalities during infancy and childhood. Whether and how prematurity alters neural specialization within visual neural networks is still unknown. We used functional and structural brain imaging to examine the visual semantic system of VLBW born (<1250 g, gestational age 25-32 weeks) adolescents (13-15 years, n = 11, 3 males) and matched term born control participants (13-15 years, n = 11, 3 males). Neurocognitive assessment revealed no group differences except for lower scores on an adaptive visuomotor integration test. All adolescents were scanned while viewing pictures of animals and tools and scrambled versions of these pictures. Both groups demonstrated animal and tool category related neural networks. Term born adolescents showed tool category related neural activity, i.e. tool pictures elicited more activity than animal pictures, in temporal and parietal brain areas. Animal category related activity was found in the occipital, temporal and frontal cortex. VLBW born adolescents showed reduced tool category related activity in the dorsal visual stream compared with controls, specifically the left anterior intraparietal sulcus, and enhanced animal category related activity in the left middle occipital gyrus and right lingual gyrus. Lower birth weight of VLBW adolescents correlated with larger thickness of the pericalcarine gyrus in the occipital cortex and smaller surface area of the superior temporal gyrus in the lateral temporal cortex. Moreover, larger thickness of the pericalcarine gyrus and smaller surface area of the superior temporal gyrus correlated with reduced tool category related activity in the parietal cortex. Together, our data suggest that very low birth weight predicts alterations of higher order visual semantic networks, particularly in the dorsal stream. The differences in neural specialization may be associated with aberrant cortical development of areas in the visual system that develop early in childhood. PMID:25458481

  4. 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

  5. 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

  6. No improvement in long-term wear and revision rates with the second-generation Biomet cup (RingLoc) in young patients

    PubMed Central

    2011-01-01

    Background A number of excellent results with the cementless titanium femoral component of the Mallory Head Total Hip Replacement have been published. Unfortunately, these excellent results have been counteracted by the poor performance of the cementless titanium acetabular components. In 1994, the HexLoc acetabular component was replaced with a second-generation design, the RingLoc. We hypothesized that the new generation would have improved the results. Methods We retrospectively studied 111 consecutive patients (150 hips) younger than 55 years. Median follow-up time was 14 (6–18) years for the HexLoc and 10 (1–14) years for the RingLoc. 7 patients were lost to follow-up and 7 patients died. The 10-year survival rate, radiographic liner wear, and radiographic signs of prosthesis failure were compared between the 2 acetabular components. Results The Kaplan-Meier survival estimate with revision for any reason as the endpoint showed a 10-year survival of 89% (95% CI: 81–97) for the HexLoc and 92% (CI: 85–98) for the RingLoc. The mean annual wear rate for the HexLoc was 0.16 (SD 0.16) mm and it was 0.15 (0.1) mm for the RingLoc (p = 0.3). The radiographic signs of failure were equally distributed between the 2 groups. Interpretation Compared to the HexLoc type, the RingLoc system did not improve the mean percentage survival at 10 years; nor did it reduce the liner wear. Despite correction of the known design flaws in the HexLoc design, the RingLoc system did not show a clinically relevant improvement compared to its predecessor. PMID:22066563

  7. Cotransplantation of embryonic mouse retina with tectum, diencephalon, or cortex to neonatal rat cortex.

    PubMed

    Sefton, A J; Lund, R D

    1988-03-22

    Retinae from embryonic mice were transplanted to the occipital cortex of neonatal rats together with their normal target regions, tectum or diencephalon, from embryonic mice or rats. In control experiments, retinae were cotransplanted with embryonic rat occipital cortex. In over 80% of the experimental animals, both transplants differentiated and grew. Ganglion cells in the retinae cotransplanted close to tectum or diencephalon survived for at least 15 weeks. Their survival was associated with the development of a distinct optic fiber layer and outgrowth of axons from the transplanted mouse retina. Specific innervation of distinct patches within the cotransplanted rat tectum or diencephalon was demonstrated by the use of an anti-mouse antibody. The innervated regions, which could be as far away as 1.3 mm from the retinae, were correlated with cytological features of the cotransplanted tectum or diencephalon. By contrast, the host cortex was never innervated by the transplanted retinae. In the control animals in which the retinae were cotransplanted with occipital cortex and in four animals in which the cotransplants lay more than 2.7 mm apart, no ganglion cells were identified and there was no evidence of an optic fiber layer, outgrowth of axons, or innervation. These results support the idea that in order to survive, retinal ganglion cells need to innervate an appropriate target region. Further, the specific innervation of regions within the cotransplanted tectum or diencephalon suggests that these target regions are able to exert a tropic influence on the axons of retinal ganglion cells, even in the absence of many of the normal structure cues. PMID:3372727

  8. Fluoroscopy and Sonographic Guided Injection of Obliquus Capitis Inferior Muscle in an Intractable Occipital Neuralgia

    PubMed Central

    Kim, Ok Sun; Jeong, Seung Min; Ro, Ji Young; Kim, Duck Kyoung; Koh, Young Cho; Ko, Young Sin; Lim, So Dug; Kim, Hae Kyoung

    2010-01-01

    Occipital neuralgia is a form of headache that involves the posterior occiput in the greater or lesser occipital nerve distribution. Pain can be severe and persistent with conservative treatment. We present a case of intractable occipital neuralgia that conventional therapeutic modalities failed to ameliorate. We speculate that, in this case, the cause of headache could be the greater occipital nerve entrapment by the obliquus capitis inferior muscle. After steroid and local anesthetic injection into obliquus capitis inferior muscles under fluoroscopic and sonographic guidance, the visual analogue scale was decreased from 9-10/10 to 1-2/10 for 2-3 weeks. The patient eventually got both greater occipital neurectomy and partial resection of obliquus capitis inferior muscles due to the short term effect of the injection. The successful steroid and local anesthetic injection for this occipital neuralgia shows that the refractory headache was caused by entrapment of greater occipital nerves by obliquus capitis inferior muscles. PMID:20552081

  9. Operational requirements for avoidance and eventual elimination of Gz-induced loss of consciousness (G-LOC) in flight.

    PubMed

    Wood, E

    1993-02-01

    Fifty years of more or less active research experiences concerning the cardiovascular, respiratory, and neurologic dynamics of G-LOC carried out in healthy humans, both on centrifuges and in flight, have convinced me that on the basis of the physiology involved and because of the risk of the very high cost in pilot lives and their planes due to G-LOC, three operational requirements should be adopted as follows. Operational Requirement I. A noninvasive continuous on-line, real-time recording of arterial pulsations at brain level should be a mandatory requirement for every human centrifuge exposure to Gz accelerations that carry an appreciable likelihood of loss of vision and/or consciousness. A similar system should be a mandatory requirement for every pilot when performing high G air-to-air or air-to-ground combat maneuvers both in training and in actual combat conditions. Operational Requirement II. A physiological G-LOC forewarning system based on arterial pulsations at head level coupled with a last-resort automatic plane recovery system should be installed in all advanced fighter aircraft. Operational Requirement III. Because of the inherent biomedical hazards associated with very high Gz protection and the risk of G-LOC when in conventional upright or partially supinated positions, an automatic 9 Gz or greater activated timer, G-LOC avoidance system should be installed in advanced fighter aircraft. This system should be set to activate an auditory G-LOC forewarning signal when a Gz level of more than 9 is maintained for 3 seconds, i.e., a period less than the cerebral anoxic reserve time. Failure of pilot response, that is, maintenance of Gz levels of greater than 9 for more than 4 seconds following this forewarning signal (i.e., a total sustained very high period of 6-7 seconds, a period equal to the average human cerebral anoxic reserve time), then activates a follow-on automatic plane recovery system. PMID:11538505

  10. iLoc-Euk: A Multi-Label Classifier for Predicting the Subcellular Localization of Singleplex and Multiplex Eukaryotic Proteins

    PubMed Central

    Chou, Kuo-Chen; Wu, Zhi-Cheng; Xiao, Xuan

    2011-01-01

    Predicting protein subcellular localization is an important and difficult problem, particularly when query proteins may have the multiplex character, i.e., simultaneously exist at, or move between, two or more different subcellular location sites. Most of the existing protein subcellular location predictor can only be used to deal with the single-location or “singleplex” proteins. Actually, multiple-location or “multiplex” proteins should not be ignored because they usually posses some unique biological functions worthy of our special notice. By introducing the “multi-labeled learning” and “accumulation-layer scale”, a new predictor, called iLoc-Euk, has been developed that can be used to deal with the systems containing both singleplex and multiplex proteins. As a demonstration, the jackknife cross-validation was performed with iLoc-Euk on a benchmark dataset of eukaryotic proteins classified into the following 22 location sites: (1) acrosome, (2) cell membrane, (3) cell wall, (4) centriole, (5) chloroplast, (6) cyanelle, (7) cytoplasm, (8) cytoskeleton, (9) endoplasmic reticulum, (10) endosome, (11) extracellular, (12) Golgi apparatus, (13) hydrogenosome, (14) lysosome, (15) melanosome, (16) microsome (17) mitochondrion, (18) nucleus, (19) peroxisome, (20) spindle pole body, (21) synapse, and (22) vacuole, where none of proteins included has pairwise sequence identity to any other in a same subset. The overall success rate thus obtained by iLoc-Euk was 79%, which is significantly higher than that by any of the existing predictors that also have the capacity to deal with such a complicated and stringent system. As a user-friendly web-server, iLoc-Euk is freely accessible to the public at the web-site http://icpr.jci.edu.cn/bioinfo/iLoc-Euk. It is anticipated that iLoc-Euk may become a useful bioinformatics tool for Molecular Cell Biology, Proteomics, System Biology, and Drug Development Also, its novel approach will further stimulate the development of predicting other protein attributes. PMID:21483473

  11. Perimetric visual field and functional MRI correlation: implications for image-guided surgery in occipital brain tumours

    PubMed Central

    Roux, F; Ibarrola, D; Lotterie, J; Chollet, F; Berry, I

    2001-01-01

    OBJECTIVE—To compare the results of visual functional MRI with those of perimetric evaluation in patients with visual field defects and retrochiasmastic tumours and in normal subjects without visual field defect. The potential clinical usefulness of visual functional MRI data during resective surgery was evaluated in patients with occipital lobe tumours.
METHODS—Eleven patients with various tumours and visual field defects and 12 normal subjects were studied by fMRI using bimonocular or monocular repetitive photic stimulation (8 Hz). The data obtained were analyzed with the statistical parametric maps software (p<10-8) and were compared with the results of Goldmann visual field perimetric evaluation. In patients with occipital brain tumours undergoing surgery, the functional data were registered in a frameless stereotactic device and the images fused into anatomical three standard planes and three dimensional reconstructions of the brain surface.
RESULTS—Two studies of patients were discarded, one because of head motion and the other because of badly followed instructions. On the remaining patients the functional activations found in the visual cortex were consistent with the results of perimetric evaluation in all but one of the patients and all the normal subjects although the results of fMRI were highly dependent on the choices of the analysis thresholds. Visual functional MRI image guided data were used in five patients with occipital brain tumours. No added postoperative functional field defect was detected.
CONCLUSIONS—There was a good correspondence between fMRI data and the results of perimetric evaluation although dependent on the analysis thresholds. Visual fMRI data registered into a frameless stereotactic device may be useful in surgical planning and tumour removal.

 PMID:11561035

  12. [A painful occipital mass revealing a posterior encephalocele].

    PubMed

    Meunier, Sarah; Michalak, Sophie; Chaigneau, Julien; Mercier, Philippe; Rousseau, Audrey

    2014-08-01

    Encephalocele is a congenital malformation caused by a neural tube defect during embryonic development. We report a case of posterior encephalocele in a 7-month-old infant with a painful occipital mass known since birth. Pathological examination of the mass showed different mature tissues derived from the brain and its coverings (e.g., neuroglia, ependymal canals and clusters of meningothelial cells). A diagnosis of encephalocele was made. The different forms of neural tube defect will be briefly discussed, especially the "aborted" forms (e.g., non-specific midline mass lesion or angioma) that the pathologist may encounter in his/her daily practice. PMID:25132445

  13. Bilateral parieto-occipital dermoid sinuses in a Rottweiler.

    PubMed

    Bornard, N; Pin, D; Carozzo, C

    2007-02-01

    Bilateral dermoid sinuses were identified on the parieto-occipital region of a Rottweiler. Diagnosis was confirmed by histological examination after successful complete surgical resection. The dermoid sinuses were independent with separate tracts. This unusual parasagittal location can be explained by craniofacial development: dermoid sinuses on the head could occur along the lines of embryological fusion and not only in the sagittal plane. A hypothesis of an origin at the level of the suture between the parietal and interparietal bones is possible in this case. PMID:17286665

  14. Occipital Neuralgia after Hair Transplantation and Its Treatment

    PubMed Central

    Siefferman, Jason; Khelemsky, Yury

    2015-01-01

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

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

    PubMed Central

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

    2012-01-01

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

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

    PubMed Central

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

    2014-01-01

    Chordoma arises from cellular remnants of the notochord. It is the most common primary malignancy of the spine in adults. Approximately 50% of chordomas arise from the sacrococcygeal area with other areas of the spine giving rise to another 15% of chordomas. Following complete resection, patients can expect a 5-year survival rate of 85%. Chordoma has a recurrence rate of 40%, which leads to a less favorable prognosis. Here, we report two cases of chordoma presenting with occipital neuralgia and cervicalgia. The first patient presented with a C1–C2 chordoma. He rejected surgical intervention and ultimately died of respiratory failure. The second patient had an atlantoaxial chordoma and underwent surgery because of continued occipital neuralgia and cervicalgia despite nerve block. This patient has remained symptom-free since his operation. The presented cases show that the patients’ willingness to participate in treatment can lead to appropriate and aggressive management of cancer pain, resulting in better outcomes in cancer treatment. PMID:26064862

  17. Investigating and Promoting Trainee Science Teachers' Conceptual Change of the Nature of Science with Digital Dialogue Games `InterLoc'

    NASA Astrophysics Data System (ADS)

    Mansour, Nasser; Wegerif, Rupert; Skinner, Nigel; Postlethwaite, Keith; Hetherington, Lindsay

    2016-04-01

    The purpose of this study is to explore how an online-structured dialogue environment supported (OSDE) collaborative learning about the nature of science among a group of trainee science teachers in the UK. The software used (InterLoc) is a linear text-based tool, designed to support structured argumentation with openers and `dialogue moves'. A design-based research approach was used to investigate multiple sessions using InterLoc with 65 trainee science teachers. Five participants who showed differential conceptual change in terms of their Nature of Science (NOS) views were purposively selected and closely followed throughout the study by using key event recall interviews. Initially, the majority of participants held naïve views of NOS. Substantial and favourable changes in these views were evident as a result of the OSDE. An examination of the development of the five participants' NOS views indicated that the effectiveness of the InterLoc discussions was mediated by cultural, cognitive, and experiential factors. The findings suggest that InterLoc can be effective in promoting reflection and conceptual change.

  18. Graphical Analysis of Electromagnetic Coupling on B-737 and B-757 Aircraft for VOR and LOC IPL Data

    NASA Technical Reports Server (NTRS)

    Jafri, Madiha; Ely, Jay; Vahala, Linda

    2005-01-01

    Electromagnetic coupling measurements were performed from numerous passenger cabin locations to aircraft instrument landing system localizer (LOC) and VHF Omni-Ranging (VOR) systems. This paper presents and compares the data for B-757 and B-737 airplanes, and provides a basis for fuzzy modeling of coupling patterns in different types of airplanes and airplanes with different antenna locations.

  19. Immature cortex lesions alter retinotopic maps and interhemispheric connections.

    PubMed

    Restrepo, C Ernesto; Manger, Paul R; Spenger, Christian; Innocenti, Giorgio M

    2003-07-01

    Unilateral lesions of the occipital visual areas performed on postnatal day 5 (P5) in the ferret are not compensated by the appearance, in the lesioned hemisphere, of visual responses at ectopic locations. Instead, when parts of the visual areas are spared, they show abnormal retinotopic organizations; furthermore, callosal connections are abnormally distributed in relation to the retinotopic maps. Lesions that completely eliminate the visual areas including the posterior parietal cortex cause the appearance of abnormal callosal connections from the primary somatosensory cortex on the lesion side to the contralateral, intact, posterior parietal cortex. The occipital visual areas (17, 18, 19, and 21) of the intact hemisphere show a normal retinotopy but lose callosal connections in territories homotopic to the lesions. These findings clarify the nature and limits of structural developmental plasticity in the visual cortex. Early in life, certain regions of cortex have been irreversibly allocated to the visual areas, but two properties defining the areas, that is, retinotopy and connections, remain modifiable. The findings might be relevant for understanding the consequences of early-onset visual cortical lesions in humans. PMID:12838520

  20. Remapping in Human Visual Cortex

    PubMed Central

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

    2008-01-01

    With each eye movement, stationary objects in the world change position on the retina, yet we perceive the world as stable. Spatial updating, or remapping, is one neural mechanism by which the brain compensates for shifts in the retinal image caused by voluntary eye movements. Remapping of a visual representation is believed to arise from a widespread neural circuit including parietal and frontal cortex. The current experiment tests the hypothesis that extrastriate visual areas in human cortex have access to remapped spatial information. We tested this hypothesis using functional magnetic resonance imaging (fMRI). We first identified the borders of several occipital lobe visual areas using standard retinotopic techniques. We then tested subjects while they performed a single-step saccade task analogous to the task used in neurophysiological studies in monkeys, and two conditions that control for visual and motor effects. We analyzed the fMRI time series data with a nonlinear, fully Bayesian hierarchical statistical model. We identified remapping as activity in the single-step task that could not be attributed to purely visual or oculomotor effects. The strength of remapping was roughly monotonic with position in the visual hierarchy: remapped responses were largest in areas V3A and hV4 and smallest in V1 and V2. These results demonstrate that updated visual representations are present in cortical areas that are directly linked to visual perception. PMID:17093130

  1. Downregulated Expression of Long Non-Coding RNA LOC101926975 Impairs both Cell Proliferation and Cell Cycle and Its Clinical Implication in Hirschsprung Disease Patients

    PubMed Central

    Shen, Ziyang; Peng, Lei; Zhu, Zhongxian; Xie, Hua; Zang, Rujin; Du, Chunxia; Chen, Guanglin; Li, Hongxing; Xia, Yankai; Tang, Weibing

    2016-01-01

    Background: Long non-coding RNAs (lncRNAs) have been reported to participate in various diseases. Hirschsprung disease (HSCR) is a common digestive disease in the new born. However, the relationship between lncRNAs and HSCR remains unclarified. Methods: We used qRT-PCR to detect the relative expression of LOC101926975 in 80 pairs of HSCR bowel tissues and matched normal bowel tissues. CCK-8 assay, transwell assay and flow cytometry were then used to evaluate the function in vitro by knocking down the LOC101926975 in SK-N-BE(2) cells. Receiver operating characteristic (ROC) curve was used to evaluate the potential diagnostic value of LOC101926975. Results: LOC101926975 was significantly downregulated in HSCR tissues with excellent correlation with FGF1. Dysregulation of LOC101926975 suppressed cell proliferation and induced G0/G1 arrest without impact on cell apoptosis or migration. Meanwhile, the AUC of LOC101926975 was 0.900 which presented great diagnostic value. Conclusions: Our study firstly investigates the potential function of LOC101926975 in HSCR and infers that LOC101926975 can distinguish HSCR from the normal ones. PMID:27076786

  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 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

  3. Occipital roof development in the Japanese musk shrew, Suncus murinus.

    PubMed Central

    Niida, S; Okada, N; Wakisaka, H; Miyata, K; Maeda, N

    1994-01-01

    The occipital squama of the Japanese musk shrew, Suncus murinus, consists only of membrane bone which arises from the periosteal bony band of the supraoccipital cartilage. No cartilaginous tectum posterius, generally forming the dorsal border to the foramen magnum, was found in the developing chondrocranium. Also additional intramembranous ossification centres were occasionally observed, and could be interpreted as being the primordium of the interparietal bone. These observations indicate that the membrane bone is homologous not with the interparietal bone but with the tectum posterius, i.e. the membranous supraoccipital bone. This is an instance of interchangeability between cartilage and membrane bone in a mammal. Images Figure 1 Figure 2 Figure 3 PMID:7961150

  4. Wisdom and eagerness to improve women's health. JICA Reproductive Health Project. Nghi Loc district.

    PubMed

    Nguyen Thi Hien

    1999-01-01

    This article concerns a report by Nguyen Thi Hien, chairperson of Nghi Loc District Women's Union on the contribution of the Japan International Cooperation Agency (JICA) project to their organization. She states that prior to the start of the JICA project, the women's union had a lot of campaigns for maternal and child health and family planning. However, the impact was not strongly felt. After the implementation of the JICA project, women in the district have become interested and excited about the various activities conducted under the project. Subsequently, more women understood the correct way to take care of their health and their children's health. Furthermore, more people in the district frequently use the services of commune health centers and district health centers. In the family planning field, contraceptive prevalence rate has increased and the number of abortions and menstrual regulations has been reduced. Despite the achievements of the campaign, the district still has a few big problems to address. These problems include: 1) a gap between commune health centers in remote areas and those near the district health centers; and 2) a low level of family planning acceptance in Catholic communes. PMID:12322468

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

    PubMed Central

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

    2014-01-01

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

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

    PubMed Central

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

    2014-01-01

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

  7. Contribution of skeletal muscle activity to the natural history of acceleration-induced loss of consciousness (G-LOC).

    PubMed

    Bagshaw, R J; Whinnery, J E

    1989-10-01

    G-LOC and the ensuing incapacitation represents an ever present threat to modern fighter aircraft and aviators. Of the techniques developed to combat gravitational induced stress, particularly such stress acting along the head to foot axis (+Gz), a variety of straining maneuvers have assumed prominence. All the latter techniques involve voluntary skeletal muscle tensing to a varying degree. It is hypothesized that the basis for the importance of skeletal muscle activity in improving G tolerance predominantly lies in the increased muscle spindle afferent activity to the reticular activating system. It is also hypothesized that the natural history of G-LOC can be significantly improved by supplementing muscle spindle activity via active and passive skeletal muscle activity. PMID:2811713

  8. StruLocPred: structure-based protein subcellular localisation prediction using multi-class support vector machine.

    PubMed

    Zhou, Wengang; Dickerson, Julie A

    2012-01-01

    Knowledge of protein subcellular locations can help decipher a protein's biological function. This work proposes new features: sequence-based: Hybrid Amino Acid Pair (HAAP) and two structure-based: Secondary Structural Element Composition (SSEC) and solvent accessibility state frequency. A multi-class Support Vector Machine is developed to predict the locations. Testing on two established data sets yields better prediction accuracies than the best available systems. Comparisons with existing methods show comparable results to ESLPred2. When StruLocPred is applied to the entire Arabidopsis proteome, over 77% of proteins with known locations match the prediction results. An implementation of this system is at http://wgzhou.ece. iastate.edu/StruLocPred/. PMID:22724294

  9. Occipital seizures and subcortical T2 hypointensity in the setting of hyperglycemia

    PubMed Central

    Putta, Swapna L.; Weisholtz, Daniel; Milligan, Tracey A.

    2014-01-01

    Introduction Occipital lobe seizures are a recognized manifestation of diabetic nonketotic hyperglycemia, though not as common as focal motor seizures. Occipital lobe white matter T2 hypointensity may suggest this diagnosis. Methods We present a case of a 66-year-old man with hyperglycemia-related occipital lobe seizures who presented with confusion, intermittent visual hallucinations, and homonymous hemianopia. Results Magnetic resonance imaging showed subcortical T2 hypointensity within the left occipital lobe with adjacent leptomeningeal enhancement. These findings were transient with disappearance in a follow-up MRI. The EEG captured frequent seizures originating in the left occipital region. HbA1c level was 13.4% on presentation, and finger stick blood glucose level was 400 mg/dl. Conclusion Hyperglycemia should be considered in the etiology of differential diagnosis of patients with visual abnormalities suspicious for seizures, especially when the MRI shows focal subcortical T2 hypointensity with or without leptomeningeal enhancement. PMID:25667880

  10. The causal role of the lateral occipital complex in visual mirror symmetry detection and grouping: an fMRI-guided TMS study.

    PubMed

    Bona, Silvia; Herbert, Andrew; Toneatto, Carlo; Silvanto, Juha; Cattaneo, Zaira

    2014-02-01

    Despite the fact that bilateral mirror symmetry is an important characteristic of the visual world, few studies have investigated its neural basis. Here we addressed this issue by investigating whether the object-selective lateral occipital (LO) cortex, a key brain region in object and shape processing, is causally involved in bilateral symmetry detection. Participants were asked to discriminate between symmetric and asymmetric dot patterns, while fMRI-guided repetitive TMS was delivered online over either the left LO, the right LO or two control sites in the occipital cortex. We found that the application of TMS over both right and left LO impaired symmetry judgments, with disruption being greater following right LO than left LO TMS, indicative of right hemisphere lateralization in symmetry processing. TMS over LO bilaterally also affected a visual contour detection task, with no evidence for hemispheric difference in this task. Overall, our results demonstrates that LO bilaterally plays a causal role in symmetry detection possibly due to symmetry acting as a strong cue in Gestalt processes mediating object recognition. PMID:24360359

  11. 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

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

    PubMed

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

    2015-09-01

    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

  13. 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

  14. Differential contribution of right and left parietal cortex to the control of spatial attention: a simultaneous EEG-rTMS study.

    PubMed

    Capotosto, Paolo; Babiloni, Claudio; Romani, Gian Luca; Corbetta, Maurizio

    2012-02-01

    We have recently shown that interference with repetitive transcranial magnetic stimulation (rTMS) of right posterior intraparietal sulcus (IPS) cortex during the allocation of spatial attention leads to abnormal desynchronization of anticipatory (pretarget) electroencephalographic alpha rhythms (8-12 Hz) in occipital-parietal cortex and the detection of subsequently presented visual targets (Capotosto et al. 2009). Since lesion data suggest that lesions of the right frontoparietal cortices produce more severe and long-lasting deficits of visual spatial attention than lesions of the left hemisphere, here, we used the mentioned rTMS-electroencephalographic procedure to test if the control of anticipatory alpha rhythms by IPS is asymmetrically organized in the 2 hemispheres. Results showed that interference with either left or right IPS during covert spatial attention equally disrupted the normally lateralized anticipatory modulation of occipital visual cortex, with stronger alpha desynchronization contralaterally to the attended visual field. In contrast, only interference with right IPS induced a paradoxical pretarget synchronization of alpha rhythms and bilateral deficits of target identification. These results suggest that the control of spatial topography of anticipatory alpha rhythms in occipital-parietal cortex is shared between left and right IPS cortex, but that right IPS uniquely contributes to a bilateral prestimulus activation of occipital visual cortex. PMID:21666126

  15. ProLoc-GO: Utilizing informative Gene Ontology terms for sequence-based prediction of protein subcellular localization

    PubMed Central

    Huang, Wen-Lin; Tung, Chun-Wei; Ho, Shih-Wen; Hwang, Shiow-Fen; Ho, Shinn-Ying

    2008-01-01

    Background Gene Ontology (GO) annotation, which describes the function of genes and gene products across species, has recently been used to predict protein subcellular and subnuclear localization. Existing GO-based prediction methods for protein subcellular localization use the known accession numbers of query proteins to obtain their annotated GO terms. An accurate prediction method for predicting subcellular localization of novel proteins without known accession numbers, using only the input sequence, is worth developing. Results This study proposes an efficient sequence-based method (named ProLoc-GO) by mining informative GO terms for predicting protein subcellular localization. For each protein, BLAST is used to obtain a homology with a known accession number to the protein for retrieving the GO annotation. A large number n of all annotated GO terms that have ever appeared are then obtained from a large set of training proteins. A novel genetic algorithm based method (named GOmining) combined with a classifier of support vector machine (SVM) is proposed to simultaneously identify a small number m out of the n GO terms as input features to SVM, where m <Loc-GO which has been implemented by using a single SVM classifier with the m = 44 and m = 60 informative GO terms, respectively. ProLoc-GO using input sequences yields test accuracies of 88.1% and 83.3% for SCL12 and SCL16, respectively, which are significantly better than the SVM-based methods, which achieve < 35% test accuracies using amino acid composition (AAC) with acid pairs and AAC with dipedtide composition. For comparison, ProLoc-GO using known accession numbers of query proteins yields test accuracies of 90.6% and 85.7%, which is also better than Hum-PLoc (85.0%) and Euk-OET-PLoc (83.7%) using ensemble classifiers with hybridization of GO terms and amphiphilic pseudo amino acid composition for SCL12 and SCL16, respectively. Conclusion The growth of Gene Ontology in size and popularity has increased the effectiveness of GO-based features. GOmining can serve as a tool for selecting informative GO terms in solving sequence-based prediction problems. The prediction system using ProLoc-GO with input sequences of query proteins for protein subcellular localization has been implemented (see Availability). PMID:18241343

  16. Densitometric comparison of 3 occipital regions for suitability of fixation.

    PubMed

    Das, Chandan; Newcomb, Anna G U S; Gaudin, Daniel P; Crawford, Neil R

    2016-04-01

    OBJECTIVE Atlantooccipital fixation is an important technique in the treatment of upper cervical spine instability. Important considerations for implant devices are obtrusiveness and propagation of torque through the device caused by cervical rotation. The authors evaluated the feasibility of 3 regions of the occiput as sites for occipitocervical fixation by examining bone mineral density at these locations. METHODS Unembalmed occiputs of 9 male and 4 female cadavers were used (mean age at time of death was 61.6 years, range 36-68 years). Studies were undertaken using caliper measurements and dual-energy x-ray absorptiometry of the superior nuchal line (SNL), the external occipital protuberance (EOP), and the inferior nuchal line (INL). RESULTS Data indicate that the bone at the INL has a similar volumetric bone density as the bone at the SNL, despite having half the thickness. Also, the volumetric bone density increases laterally along the nuchal lines. CONCLUSIONS Most hardware fixation is centered on stabilization at the EOP and the SNL. On the basis of these radiological results, the INL shows promise as a potential alternative site for screw placement in occipitocervical fixation. PMID:26722952

  17. 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

  18. [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

  19. 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

  20. Differential Contribution of Right and Left Temporo-Occipital and Anterior Temporal Lesions to Face Recognition Disorders

    PubMed Central

    Gainotti, Guido; Marra, Camillo

    2011-01-01

    In the study of prosopagnosia, several issues (such as the specific or non-specific manifestations of prosopagnosia, the unitary or non-unitary nature of this syndrome and the mechanisms underlying face recognition disorders) are still controversial. Two main sources of variance partially accounting for these controversies could be the qualitative differences between the face recognition disorders observed in patients with prevalent lesions of the right or left hemisphere and in those with lesions encroaching upon the temporo-occipital (TO) or the (right) anterior temporal cortex. Results of our review seem to confirm these suggestions. Indeed, they show that (a) the most specific forms of prosopagnosia are due to lesions of a right posterior network including the occipital face area and the fusiform face area, whereas (b) the face identification defects observed in patients with left TO lesions seem due to a semantic defect impeding access to person-specific semantic information from the visual modality. Furthermore, face recognition defects resulting from right anterior temporal lesions can usually be considered as part of a multimodal people recognition disorder. The implications of our review are, therefore, the following: (1) to consider the components of visual agnosia often observed in prosopagnosic patients with bilateral TO lesions as part of a semantic defect, resulting from left-sided lesions (and not from prosopagnosia proper); (2) to systematically investigate voice recognition disorders in patients with right anterior temporal lesions to determine whether the face recognition defect should be considered a form of “associative prosopagnosia” or a form of the “multimodal people recognition disorder.” PMID:21687793

  1. The human cerebral cortex flattens during adolescence.

    PubMed

    Alemán-Gómez, Yasser; Janssen, Joost; Schnack, Hugo; Balaban, Evan; Pina-Camacho, Laura; Alfaro-Almagro, Fidel; Castro-Fornieles, Josefina; Otero, Soraya; Baeza, Immaculada; Moreno, Dolores; Bargalló, Nuria; Parellada, Mara; Arango, Celso; Desco, Manuel

    2013-09-18

    The human cerebral cortex appears to shrink during adolescence. To delineate the dynamic morphological changes involved in this process, 52 healthy male and female adolescents (11-17 years old) were neuroimaged twice using magnetic resonance imaging, approximately 2 years apart. Using a novel morphometric analysis procedure combining the FreeSurfer and BrainVisa image software suites, we quantified global and lobar change in cortical thickness, outer surface area, the gyrification index, the average Euclidean distance between opposing sides of the white matter surface (gyral white matter thickness), the convex ("exposed") part of the outer cortical surface (hull surface area), sulcal length, depth, and width. We found that the cortical surface flattens during adolescence. Flattening was strongest in the frontal and occipital cortices, in which significant sulcal widening and decreased sulcal depth co-occurred. Globally, sulcal widening was associated with cortical thinning and, for the frontal cortex, with loss of surface area. For the other cortical lobes, thinning was related to gyral white matter expansion. The overall flattening of the macrostructural three-dimensional architecture of the human cortex during adolescence thus involves changes in gray matter and effects of the maturation of white matter. PMID:24048830

  2. 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

  3. 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

  4. Long-Term Effects of Serial Anodal tDCS on Motion Perception in Subjects with Occipital Stroke Measured in the Unaffected Visual Hemifield

    PubMed Central

    Olma, M. C.; Dargie, R. A.; Behrens, J. R.; Kraft, A.; Irlbacher, K.; Fahle, M.; Brandt, S. A.

    2013-01-01

    Transcranial direct current stimulation (tDCS) is a novel neuromodulatory tool that has seen early transition to clinical trials, although the high variability of these findings necessitates further studies in clinically relevant populations. The majority of evidence into effects of repeated tDCS is based on research in the human motor system, but it is unclear whether the long-term effects of serial tDCS are motor-specific or transferable to other brain areas. This study aimed to examine whether serial anodal tDCS over the visual cortex can exogenously induce long-term neuroplastic changes in the visual cortex. However, when the visual cortex is affected by a cortical lesion, up-regulated endogenous neuroplastic adaptation processes may alter the susceptibility to tDCS. To this end, motion perception was investigated in the unaffected hemifield of subjects with unilateral visual cortex lesions. Twelve subjects with occipital ischemic lesions participated in a within-subject, sham-controlled, double-blind study. MRI-registered sham or anodal tDCS (1.5 mA, 20 min) was applied on five consecutive days over the visual cortex. Motion perception was tested before and after stimulation sessions and at 14- and 28-day follow-up. After a 16-day interval an identical study block with the other stimulation condition (anodal or sham tDCS) followed. Serial anodal tDCS over the visual cortex resulted in an improvement in motion perception, a function attributed to MT/V5. This effect was still measurable at 14- and 28-day follow-up measurements. Thus, this may represent evidence for long-term tDCS-induced plasticity and has implications for the design of studies examining the time course of tDCS effects in both the visual and motor systems. PMID:23805097

  5. Long-Term Effects of Serial Anodal tDCS on Motion Perception in Subjects with Occipital Stroke Measured in the Unaffected Visual Hemifield.

    PubMed

    Olma, M C; Dargie, R A; Behrens, J R; Kraft, A; Irlbacher, K; Fahle, M; Brandt, S A

    2013-01-01

    Transcranial direct current stimulation (tDCS) is a novel neuromodulatory tool that has seen early transition to clinical trials, although the high variability of these findings necessitates further studies in clinically relevant populations. The majority of evidence into effects of repeated tDCS is based on research in the human motor system, but it is unclear whether the long-term effects of serial tDCS are motor-specific or transferable to other brain areas. This study aimed to examine whether serial anodal tDCS over the visual cortex can exogenously induce long-term neuroplastic changes in the visual cortex. However, when the visual cortex is affected by a cortical lesion, up-regulated endogenous neuroplastic adaptation processes may alter the susceptibility to tDCS. To this end, motion perception was investigated in the unaffected hemifield of subjects with unilateral visual cortex lesions. Twelve subjects with occipital ischemic lesions participated in a within-subject, sham-controlled, double-blind study. MRI-registered sham or anodal tDCS (1.5 mA, 20 min) was applied on five consecutive days over the visual cortex. Motion perception was tested before and after stimulation sessions and at 14- and 28-day follow-up. After a 16-day interval an identical study block with the other stimulation condition (anodal or sham tDCS) followed. Serial anodal tDCS over the visual cortex resulted in an improvement in motion perception, a function attributed to MT/V5. This effect was still measurable at 14- and 28-day follow-up measurements. Thus, this may represent evidence for long-term tDCS-induced plasticity and has implications for the design of studies examining the time course of tDCS effects in both the visual and motor systems. PMID:23805097

  6. Investigating object representations during change detection in human extrastriate cortex

    PubMed Central

    Schwarzkopf, D Samuel; Silvanto, Juha; Gilaie-Dotan, Sharon; Rees, Geraint

    2010-01-01

    Detecting a change in a visual stimulus is particularly difficult when it is accompanied by a visual disruption such as a saccade or flicker. In order to say whether a stimulus has changed across such a disruption, some neural trace must persist. Here we investigated whether two different regions of the human extrastriate visual cortex contain neuronal populations encoding such a trace. Participants viewed a stimulus that included various objects and a short blank period (flicker) made it difficult to distinguish whether an object in the stimulus had changed or not. By applying transcranial magnetic stimulation (TMS) during the visual disruption we show that the lateral occipital (LO) cortex, but not the occipital face area, contains a sustained representation of a visual stimulus. TMS over LO improved the sensitivity and response bias for detecting changes by selectively reducing false alarms. We suggest that TMS enhanced the initial object representation and thus boosted neural events associated with object repetition. Our findings show that neuronal signals in the human LO cortex carry a sustained neural trace that is necessary for detecting the repetition of a stimulus. PMID:20946235

  7. Traumatic atlanto-occipital dislocation presenting with Dysphagia as the chief complaint: a case report.

    PubMed

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

    2013-06-01

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

  8. Orbitofrontal Cortex Volume and Brain Reward Response in Obesity

    PubMed Central

    Shott, Megan E.; Cornier, Marc-Andre; Mittal, Vijay A.; Pryor, Tamara L.; Orr, Joseph M.; Brown, Mark S.; Frank, Guido K.W.

    2014-01-01

    Background/Objectives What drives overconsumption of food is poorly understood. Alterations in brain structure and function could contribute to increased food seeking. Recently brain orbitofrontal cortex volume has been implicated in dysregulated eating but little is know how brain structure relates to function. Subjects/Methods We examined obese (n=18, age=28.7.4±8.3 years) and healthy control women (n=24, age=27.4±6.3 years) using a multimodal brain imaging approach. We applied magnetic resonance and diffusion tensor imaging to study brain gray and white matter volume as well as white matter integrity, and tested whether orbitofrontal cortex volume predicts brain reward circuitry activation in a taste reinforcement-learning paradigm that has been associated with dopamine function. Results Obese individuals displayed lower gray and associated white matter volumes (p<.05 family wise error (FWE)-small volume corrected) compared to controls in the orbitofrontal cortex, striatum, and insula. White matter integrity was reduced in obese individuals in fiber tracts including the external capsule, corona radiata, sagittal stratum, and the uncinate, inferior fronto-occipital, and inferior longitudinal fasciculi. Gray matter volume of the gyrus rectus at the medial edge of the orbitofrontal cortex predicted functional taste reward-learning response in frontal cortex, insula, basal ganglia, amygdala, hypothalamus and anterior cingulate cortex in control but not obese individuals. Conclusions This study indicates a strong association between medial orbitofrontal cortex volume and taste reinforcement-learning activation in the brain in control but not in obese women. Lower brain volumes in the orbitofrontal cortex and other brain regions associated with taste reward function as well as lower integrity of connecting pathways in obesity may support a more widespread disruption of reward pathways. The medial orbitofrontal cortex is an important structure in the termination of food intake and disturbances in this and related structures could contribute to overconsumption of food in obesity. PMID:25027223

  9. Pediatric atlanto-occipital dissociation: radiographic findings and clinical outcome

    PubMed Central

    du Plessis, Jean-Pierre; Dix-Peek, Stewart; Hoffman, Eduard Bernard; Wieselthaler, Nicky; Dunn, Robert Neil

    2012-01-01

    Study design: Retrospective diagnostic feasibility study and clinical review. Objectives: To evaluate the feasibility of making an initial atlanto-occipital dissociation (AOD) diagnosis from four radiological measurements of the craniocervical relationship on lateral cervical spine x-rays and to assess the AOD patients' clinical outcomes relative to their magnetic resonance imaging (MRI) findings. Methods: The Powers ratio, Wackenheim line, basion-dens distance (BDD), and the C1/2:C2/3 interspinous ratio were measured in 58 pediatric controls and ten MRI-confirmed patients with AOD. The ability to identify the required anatomical landmarks and make the measurements was noted and sensitivity and specificity calculated. The correspondence between the clinical presentation and outcomes for patients with AOD and their MRI features was investigated. Results: Clear landmarks for measuring interspinous ratio and Wackenheim line were confirmed by all x-rays. The BDD was measureable in 90% and the Powers ratio could be calculated in only possible in 59%. The interspinous ratio and BDD offered high sensitivities and specificity. Although the Wackenheim line was consistantly measured, it conferred a low sensitivity but reasonable specificity. The Powers ratio offered high specificity with low sensitivity. On MRI, all patients with AOD had apical ligament disruption, with a high rate of interspinous ligamentous injury (8/9); prevertebral swelling (7/9); retroclival hematoma (6/9); and tectorial membrane injury (4/9). The only MRI feature associated with poor outcome was that of altered cord signal. Both patients who died had cord signal changes on T1- and T2-weighted images. The third patient with cord signal change was limited to T2 changes with a normal T1. He had a C5-L3 sensory deficit that resolved. The degree of tectorial membrane injury did not appear to influence outcome. Conclusions: The BDD and interspinous ratio offer the best measures for initial x-ray diagnosis of AOD. This will alert the surgeon to the need for MRI. These patients often have a reduced level of consciousness, thus making clinical evaluation difficult. The MRI findings, although apparently indicative of severe abnormality, did not actually correspond to outcomes except for the presence of T1 cord signal changes that matched with severe neurological impairment and subsequent death. PMID:23236302

  10. 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

  11. 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.

  12. 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…

  13. Dissociation of object and spatial visual processing pathways in human extrastriate cortex.

    PubMed Central

    Haxby, J V; Grady, C L; Horwitz, B; Ungerleider, L G; Mishkin, M; Carson, R E; Herscovitch, P; Schapiro, M B; Rapoport, S I

    1991-01-01

    The existence and neuroanatomical locations of separate extrastriate visual pathways for object recognition and spatial localization were investigated in healthy young men. Regional cerebral blood flow was measured by positron emission tomography and bolus injections of H2(15)O, while subjects performed face matching, dot-location matching, or sensorimotor control tasks. Both visual matching tasks activated lateral occipital cortex. Face discrimination alone activated a region of occipitotemporal cortex that was anterior and inferior to the occipital area activated by both tasks. The spatial location task alone activated a region of lateral superior parietal cortex. Perisylvian and anterior temporal cortices were not activated by either task. These results demonstrate the existence of three functionally dissociable regions of human visual extrastriate cortex. The ventral and dorsal locations of the regions specialized for object recognition and spatial localization, respectively, suggest some homology between human and nonhuman primate extrastriate cortex, with displacement in human brain, possibly related to the evolution of phylogenetically newer cortical areas. Images PMID:2000370

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

    PubMed

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

    2011-07-01

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

  15. Modelling and simulation of passive Lab-on-a-Chip (LoC) based micromixer for clinical application

    NASA Astrophysics Data System (ADS)

    Saikat, Chakraborty; Sharath, M.; Srujana, M.; Narayan, K.; Pattnaik, Prasant Kumar

    2016-03-01

    In biomedical application, micromixer is an important component because of many processes requires rapid and efficient mixing. At micro scale, the flow is Laminar due to small channel size which enables controlled rapid mixing. The reduction in analysis time along with high throughput can be achieved with the help of rapid mixing. In LoC application, micromixer is used for mixing of fluids especially for the devices which requires efficient mixing. Micromixer of this type of microfluidic devices with a rapid mixing is useful in application such as DNA/RNA synthesis, drug delivery system & biological agent detection. In this work, we design and simulate a microfluidic based passive rapid micromixer for lab-on-a-chip application.

  16. Silica-on-silicon (SOS)-PDMS platform integrated lab-on-a-chip (LOC) for quantum dot applications

    NASA Astrophysics Data System (ADS)

    Ozhikandathil, Jayan; Packirisamy, Muthukumaran

    2010-06-01

    Integration of microfluidics with the integrated optical waveguides enables the realization of devices capable of performing the biodetection and analysis on small scale using fluorescence biolabels such as Quantum Dot (QD). Polydimethylsiloxane (PDMS) has been an excellent choice to build the optical bio-microfluidic systems because of its biocompatibility, optical properties and low cost fabrication process. In this work, we report a method to integrate the microfluidics channels and waveguides fabricated on Silica-on-silicon (SOS) and PDMS platform for the realization of a Lab-on-a-chip (LOC). Performance of the device tested by measuring fluorescence from the laser excited Quantum Dot (QD655) solution reveals that the developed device is suitable for performing the QD based biodetection and analysis efficiently.

  17. 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

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

    PubMed Central

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

    2014-01-01

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

  19. 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

  20. Task modulates category selectivity along a gradient from occipitotemporal cortex to prefrontal cortex in word- and face-selective regions.

    PubMed

    Bugatus, Lior; Weiner, Kevin; Grill-Spector, Kalanit

    2015-01-01

    The human brain contains separate functional networks constituting of multiple regions across occipital, temporal, and prefrontal cortices that are involved in processing faces and words. It is hypothesized that regions in occipitotemporal cortex process visual attributes of these stimuli and regions in the prefrontal cortex are involved with higher cognitive functions such as selective attention or working memory. However, it is unknown whether task and stimuli differentially affect responses of regions within these networks. Here we addressed this question by scanning 9 subjects using fMRI while they viewed stimuli from five categories: faces, bodies, houses, cars, and pseudo-words. Subjects performed in the same session three tasks in separate runs, and task order was counterbalanced across subjects. Oddball: subjects detected a randomly presented phase-scrambled image. Working memory: subjects indicated whether a stimulus repeated after an intervening image. Selective attention: subjects viewed superimposed images from two categories, attended to one stimulus category and reported when the attended stimulus was flipped upside-down. Word- and face-selective regions of interest in analogous anatomical locations were identified independently in each subject. Our analysis found a differential effect of task on stimulus selectivity across category-selective regions (task by region interaction, F(8,184) = 2.68, p = 0.008). Specifically, category-selectivity in lateral occipital cortex regions was similar across tasks, but was moderately increased in ventral temporal regions during the working memory task. In prefrontal cortex, however, the working memory task had a significant effect on category-selectivity: there was prominent face- and word-selectivity during the working memory task, but insignificant selectivity during the oddball and selective attention tasks. Together, these results reveal a gradient of selectivity that is modulated differentially by task, suggesting that the multiplicity of face- and word-selective regions may be related to task-relevant functional differences of individual components in these functional networks. Meeting abstract presented at VSS 2015. PMID:26326858

  1. Anesthetic management of a newborn with occipital meningocele for magnetic resonance imaging.

    PubMed

    Neeta, S; Upadya, Madusudhan; Pachala, Sri Sruthi

    2015-01-01

    Cranial Meningocoele is a term which represents herniation of meninges and cerebrospinal fluid through the congenital defect in the cranium. Anaesthetic challenges in the management of neonates with occipital meningocoele include airway management and proper positioning of the neonate without pressure on the meningocoele sac so as to preventthe rupture of the membranes. Associated congenital anomalies also can cause anaesthesia and procedure related complications. Other difficulties include performing a difficult airway case in an unfamiliar environment outside operation theatre. We report a case of 6 day old neonate with occipital meningocoele posted for MRI brain and the successful anaesthetic management. PMID:26417133

  2. Dopamine D1-stimulated adenylyl cyclase activity in cerebral cortex of autopsied human brain.

    PubMed

    Tong, J; Ross, B M; Sherwin, A L; Kish, S J

    2001-08-01

    Although the cerebral cortical dopamine D(1) receptor is considered to play a role in normal and abnormal brain function, little information is available on its characteristics in human brain. We compared dopamine-stimulated adenylyl cyclase (AC) activity in homogenates of cerebral cortex (frontal, temporal, parietal, occipital and cingulate cortex) of autopsied brain of neurologically normal subjects to that in striatum. Cerebral cortical AC activity was modestly and dose-dependently stimulated by dopamine (maximal 20-30%) with low microM EC50s and such stimulation was inhibited by the selective dopamine D1 receptor antagonist SCH23390. The magnitude of the maximal stimulation by dopamine was similar in autopsied and biopsied cerebral cortex. The extent of maximal stimulation was similar to that in dopamine-rich striatum (caudate, putamen and nucleus accumbens), despite much lower density of dopamine D1 receptors in cerebral cortex vs. striatum. The EC50 for dopamine stimulation in cerebral cortex (approximately 1 microM) was lower than that for caudate and putamen (approximately 3 microM). No detectable dopamine stimulation was observed in cerebellar cortex, thalamus or hippocampus. Dopamine stimulation in both cerebral cortex and striatum was independent of calcium activation. We conclude that dopamine stimulated AC can be measured in cerebral cortex of human brain allowing for the possibility that this process can be examined in human brain disorders in which dopaminergic abnormalities are suspected. PMID:11408090

  3. 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

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

    PubMed Central

    Thorne, Jeremy D.; Bleichner, Martin G.; Debener, Stefan

    2016-01-01

    Cochlear implant (CI) users show higher auditory-evoked activations in visual cortex and higher visual-evoked activation in auditory cortex compared to normal hearing (NH) controls, reflecting functional reorganization of both visual and auditory modalities. Visual-evoked activation in auditory cortex is a maladaptive functional reorganization whereas auditory-evoked activation in visual cortex is beneficial for speech recognition in CI users. We investigated their joint influence on CI users' speech recognition, by testing 20 postlingually deafened CI users and 20 NH controls with functional near-infrared spectroscopy (fNIRS). Optodes were placed over occipital and temporal areas to measure visual and auditory responses when presenting visual checkerboard and auditory word stimuli. Higher cross-modal activations were confirmed in both auditory and visual cortex for CI users compared to NH controls, demonstrating that functional reorganization of both auditory and visual cortex can be identified with fNIRS. Additionally, the combined reorganization of auditory and visual cortex was found to be associated with speech recognition performance. Speech performance was good as long as the beneficial auditory-evoked activation in visual cortex was higher than the visual-evoked activation in the auditory cortex. These results indicate the importance of considering cross-modal activations in both visual and auditory cortex for potential clinical outcome estimation. PMID:26819766

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

    ERIC Educational Resources Information Center

    Inselberg, Rachel; And Others

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

  6. 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

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

    PubMed

    Dixon, Marilu; Ratliff, Catherine

    2011-09-01

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

  8. Anastomosis of occipital artery to anterior inferior cerebellar artery for vertebrobasilar junction stenosis.

    PubMed

    Ausman, J I; Diaz, F G; de los Reyes, R A; Pak, H; Patel, S; Boulos, R

    1981-08-01

    A new approach to revascularization of the posterior fossa for vertebrobasilar insufficiency due to vertebrobasilar junction stenosis is reported. The procedure involves anastomosing the occipital artery to a branch of the anterior inferior cerebellar artery. Rationale for the procedure and surgical technique are discussed. PMID:7280991

  9. Occipital MEG Activity in the Early Time Range (<300 ms) Predicts Graded Changes in Perceptual Consciousness.

    PubMed

    Andersen, Lau M; Pedersen, Michael N; Sandberg, Kristian; Overgaard, Morten

    2016-06-01

    Two electrophysiological components have been extensively investigated as candidate neural correlates of perceptual consciousness: An early, occipitally realized component occurring 130-320 ms after stimulus onset and a late, frontally realized component occurring 320-510 ms after stimulus onset. Recent studies have suggested that the late component may not be uniquely related to perceptual consciousness, but also to sensory expectations, task associations, and selective attention. We conducted a magnetoencephalographic study; using multivariate analysis, we compared classification accuracies when decoding perceptual consciousness from the 2 components using sources from occipital and frontal lobes. We found that occipital sources during the early time range were significantly more accurate in decoding perceptual consciousness than frontal sources during both the early and late time ranges. These results are the first of its kind where the predictive values of the 2 components are quantitatively compared, and they provide further evidence for the primary importance of occipital sources in realizing perceptual consciousness. The results have important consequences for current theories of perceptual consciousness, especially theories emphasizing the role of frontal sources. PMID:26009612

  10. Giant cell tumor of the occipital bone in a case of von Recklinghausen neurofibromatosis.

    PubMed

    Opitz, H; Petersen, D; Heiss, E; Duffner, F; Meyermann, R

    1996-01-01

    Von Recklinghausen neurofibromatosis (NF1) is the most common hereditary syndrome predisposing to neoplasia. The most common symptomatic manifestation of NF1 is the plexiform neurofibroma. We describe the case of a patient with classical von Recklinghausen neurofibromatosis presenting with a giant cell tumor (GCT) of the occipital bone infiltrating a surrounding plexiform neurofibroma. PMID:8836608

  11. The white matter of the human cerebrum: part I The occipital lobe by Heinrich Sachs.

    PubMed

    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

  12. Sounds activate visual cortex and improve visual discrimination.

    PubMed

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

    2014-07-16

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

  13. 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

  14. 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

  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. Characterization of visual percepts evoked by noninvasive stimulation of the human posterior parietal cortex.

    PubMed

    Fried, Peter J; Elkin-Frankston, Seth; Rushmore, Richard Jarrett; Hilgetag, Claus C; Valero-Cabre, Antoni

    2011-01-01

    Phosphenes are commonly evoked by transcranial magnetic stimulation (TMS) to study the functional organization, connectivity, and excitability of the human visual brain. For years, phosphenes have been documented only from stimulating early visual areas (V1-V3) and a handful of specialized visual regions (V4, V5/MT+) in occipital cortex. Recently, phosphenes were reported after applying TMS to a region of posterior parietal cortex involved in the top-down modulation of visuo-spatial processing. In the present study, we systematically characterized parietal phosphenes to determine if they are generated directly by local mechanisms or emerge through indirect activation of other visual areas. Using technology developed in-house to record the subjective features of phosphenes, we found no systematic differences in the size, shape, location, or frame-of-reference of parietal phosphenes when compared to their occipital counterparts. In a second experiment, discrete deactivation by 1 Hz repetitive TMS yielded a double dissociation: phosphene thresholds increased at the deactivated site without producing a corresponding change at the non-deactivated location. Overall, the commonalities of parietal and occipital phosphenes, and our ability to independently modulate their excitability thresholds, lead us to conclude that they share a common neural basis that is separate from either of the stimulated regions. PMID:22087266

  17. 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

  18. 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

  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%; α-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. A Major Human White Matter Pathway Between Dorsal and Ventral Visual Cortex.

    PubMed

    Takemura, Hiromasa; Rokem, Ariel; Winawer, Jonathan; Yeatman, Jason D; Wandell, Brian A; Pestilli, Franco

    2016-05-01

    Human visual cortex comprises many visual field maps organized into clusters. A standard organization separates visual maps into 2 distinct clusters within ventral and dorsal cortex. We combined fMRI, diffusion MRI, and fiber tractography to identify a major white matter pathway, the vertical occipital fasciculus (VOF), connecting maps within the dorsal and ventral visual cortex. We use a model-based method to assess the statistical evidence supporting several aspects of the VOF wiring pattern. There is strong evidence supporting the hypothesis that dorsal and ventral visual maps communicate through the VOF. The cortical projection zones of the VOF suggest that human ventral (hV4/VO-1) and dorsal (V3A/B) maps exchange substantial information. The VOF appears to be crucial for transmitting signals between regions that encode object properties including form, identity, and color and regions that map spatial information. PMID:25828567

  1. 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

  2. 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.

  3. Occipital neuralgia secondary to unilateral atlantoaxial osteoarthritis: Case report and review of the literature

    PubMed Central

    Guha, Daipayan; Mohanty, Chandan; Tator, Charles H.; Shamji, Mohammed F.

    2015-01-01

    Background: Atlantoaxial osteoarthritis (AAOA), either in isolation or in the context of generalized peripheral or spinal arthritis, presents most commonly with neck pain and limitation of cervical rotational range of motion. Occipital neuralgia (ON) is only rarely attributed to AAOA, as fewer than 30 cases are described in the literature. Case Description: A 64-year-old female presented with progressive incapacitating cervicalgia and occipital headaches, refractory to medications, and local anesthetic blocks. Computed tomography and magnetic resonance imaging studies documented advanced unilateral atlantoaxial arthrosis with osteophytic compression that dorsally displaced the associated C2 nerve root. Surgical decompression and atlantoaxial fusion achieved rapid and complete relief of neuralgia. Ultimately, postoperative spinal imaging revealed osseous union. Conclusions: Atlantoaxial arthrosis must be considered in the differential diagnosis of ON. Surgical treatment is effective for managing refractory cases. Intraoperative neuronavigation is also a useful adjunct to guide instrumentation and the intraoperative extent of bony decompression. PMID:26759731

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

    PubMed

    Gips, Hadas; Hiss, Jehuda; Davidson, Benjamin

    2010-11-01

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

  5. Prenatal ultrasound and MRI findings of temporal and occipital lobe dysplasia in a twin with achondroplasia.

    PubMed

    Pugash, D; Lehman, A M; Langlois, S

    2014-09-01

    Thanatophoric dysplasia, hypochondroplasia and achondroplasia are all caused by FGFR3 (fibroblast growth factor receptor 3) mutations. Neuropathological findings of temporal lobe dysplasia are found in thanatophoric dysplasia, and temporal and occipital lobe abnormalities have been described recently in brain imaging studies of children with hypochondroplasia. We describe twins discordant for achondroplasia, in one of whom the prenatal diagnosis was based on ultrasound and fetal MRI documentation of temporal and occipital lobe abnormalities characteristic of hypochondroplasia, in addition to the finding of short long bones. Despite the intracranial findings suggestive of hypochondroplasia, achondroplasia was confirmed following postnatal clinical and genetic testing. These intracranial abnormalities have not been previously described in a fetus with achondroplasia. PMID:24616001

  6. Parietal and occipital encephalocele in same child: A rarest variety of double encephalocele.

    PubMed

    Sharma, Somnath; Ojha, Bal Krishan; Chandra, Anil; Singh, Sunil Kumar; Srivastava, Chhitij

    2016-05-01

    An encephalocele is a protrusion of the brain and/or meninges through a defect in the skull. Based on the location of the skull defect they are classified into sincipital, basal, occipital or parietal varieties. Occurrence of more than one Encephalocele in a patient is very rare and very few cases of double encephalocele are reported. We report an interesting case where a parietal and an occipital encephalocele were present together. The patient was a 2 months boy who was brought to us with complaints of two swelling on the scalp since birth. Neuroimaging studies confirmed it to be a case of double encephalocele. The rarity of the findings prompted us to report this case. The presentation and management of the case along with and review of the relevant literature is presented. PMID:26876766

  7. Chronic daily headaches secondary to greater auricular and lesser occipital neuromas following endolymphatic shunt surgery.

    PubMed

    Vorobeichik, Leon; Fallucco, Michael A; Hagan, Robert R

    2012-01-01

    In head and neck surgery, peripheral sensory nerves are at risk for traumatic injury. These injuries are known to be peripheral triggers of chronic headaches if left untreated or unrecognised. We report the case of a patient that presented with a severe headache, nausea and emesis of 2 years duration following endolymphatic shunt placement for Meniere's disease. Nerve blockade suggested a peripheral trigger, and surgical exploration of the incision site revealed traumatic neuromas of the greater auricular and lesser occipital nerves. Subsequent nerve resection yielded complete symptomatic relief. This is the first case report of a peripherally triggered migraine headache due to the development of neuromas of the greater auricular and lesser occipital nerves, also representing a previously unreported complication of endolymphatic shunt placement. It is recommended that in patients presenting with intractable migraines and a history of head and neck surgery, diagnostic nerve blockage be used to assess for neuromas. PMID:23048004

  8. Occipital lobe seizures: Rare hyperglycemic sequelae of type 1 diabetes mellitus

    PubMed Central

    Jalal, Muhammed Jasim Abdul; Menon, Murali Krishna; Kumar, K. Arun; Gomez, Ramesh

    2015-01-01

    A 15-year-old boy presented with osmotic symptoms and photopsia. He had short-term memory impairment, visual hallucinations, and headache. His random blood sugar was 474 mg/dl, HbA1c −9.4%, and glutamic acid decarboxylase −65 >2000 IU/ml. Magnetic resonance imaging brain and cerebrospinal fluid study were normal. Digital electroencephalography was suggestive of bilateral hemispheric occipital lobe seizures. He responded well to insulin and antiepileptic medications.

  9. Corticocortical connections mediate primary visual cortex responses to auditory stimulation in the blind.

    PubMed

    Klinge, Corinna; Eippert, Falk; Röder, Brigitte; Büchel, Christian

    2010-09-22

    Blind individuals have to rely on nonvisual information to a greater extent than sighted to efficiently interact with the environment, and consequently exhibit superior skills in their spared modalities. These performance advantages are often paralleled by responses in the occipital cortex, which have been suggested to be essential for nonvisual processing in the blind. However, it is currently unclear through which pathways (i.e., thalamocortical or corticocortical connections) nonvisual information reaches the occipital cortex of the blind. Here, we used functional magnetic resonance imaging to study blind and matched sighted humans with an auditory discrimination paradigm and used dynamic causal modeling to investigate the effective connectivity underlying auditory activations in the primary visual cortex of blind volunteers. Model comparison revealed that a model connecting the medial geniculate nucleus (MGN), primary auditory cortex (A1), and primary visual cortex (V1) in a bidirectional manner outperformed all other models in both groups. Regarding inference on model parameters, we observed that basic auditory mechanisms (i.e., sensory input to MGN and connections from MGN to A1) did not differ significantly between the two groups. In contrast, we found clear evidence for stronger corticocortical connections from A1 to V1 in the blind, whereas results with regard to thalamocortical enhancement (from MGN to V1 and, in a control analysis, from the lateral geniculate nucleus to V1) were not consistent. These results suggest that plastic changes especially in corticocortical connectivity allow auditory information to evoke responses in the primary visual cortex of blind individuals. PMID:20861384

  10. Dissociation between Conceptual and Perceptual Implicit Memory: Evidence from Patients with Frontal and Occipital Lobe Lesions

    PubMed Central

    Gong, Liang; Wang, JiHua; Yang, XuDong; Feng, Lei; Li, Xiu; Gu, Cui; Wang, MeiHong; Hu, JiaYun; Cheng, Huaidong

    2016-01-01

    The latest neuroimaging studies about implicit memory (IM) have revealed that different IM types may be processed by different parts of the brain. However, studies have rarely examined what subtypes of IM processes are affected in patients with various brain injuries. Twenty patients with frontal lobe injury, 25 patients with occipital lobe injury, and 29 healthy controls (HC) were recruited for the study. Two subtypes of IM were investigated by using structurally parallel perceptual (picture identification task) and conceptual (category exemplar generation task) IM tests in the three groups, as well as explicit memory (EM) tests. The results indicated that the priming of conceptual IM and EM tasks in patients with frontal lobe injury was poorer than that observed in HC, while perceptual IM was identical between the two groups. By contrast, the priming of perceptual IM in patients with occipital lobe injury was poorer than that in HC, whereas the priming of conceptual IM and EM was similar to that in HC. This double dissociation between perceptual and conceptual IM across the brain areas implies that occipital lobes may participate in perceptual IM, while frontal lobes may be involved in processing conceptual memory. PMID:26793093

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

    PubMed

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

    2014-07-01

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

  12. Recognition and management of atlanto-occipital dislocation: improving survival from an often fatal condition

    PubMed Central

    Fisher, Charles G.; Sun, John C.L.; Dvorak, Marcel

    2001-01-01

    Objective To provide an overview of atlanto-occipital dislocation and associated occipital condyle fractures so as to alert physicians to this rare injury and potentially improve patient outcome. The pertinent anatomy, mechanism of injury, clinical and radiologic evaluation and the management of these rare injuries are discussed in an attempt to alert physicians to this type of injury and to improve outcome. Data sources The data were obtained from a MEDLINE search of the English literature from 1966 to 1999 and the experience of 4 spine surgeons at a quaternary care acute spinal cord injury unit. Study selection Detailed anatomic and epidemiologically sound radiology studies were identified and analyzed. Only small retrospective studies or case series were available in the literature. Data extraction Valid anatomic, biomechanical and radiologic evaluation was extracted from studies. Clinical data came from limited studies and expert opinion. Data synthesis Early diagnosis is essential and is facilitated by a detailed clinical examination and strict adherence to an imaging algorithm that includes CT and MRI scanning. When the dislocation is identified, timely gentle reduction and prompt stabilization throuigh nonoperative or operative means is found to optimize patient outcome. Conclusions Atlanto-occipital dislocation should be suspected in any patient involved in a high speed motor vehicle or pedestrian collision. Once suspected, proper imaging and appropriate management of these once fatal injuries can improve survival and neurologic outcome. PMID:11764873

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

    PubMed

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

    2014-05-01

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

  14. Long Noncoding RNA LOC100129973 Suppresses Apoptosis by Targeting miR-4707-5p and miR-4767 in Vascular Endothelial Cells.

    PubMed

    Lu, Wei; Huang, Shu Ya; Su, Le; Zhao, Bao Xiang; Miao, Jun Ying

    2016-01-01

    Accumulating evidence has demonstrated that long non-coding RNAs (lncRNAs) are key regulators of multiple biological processes by altering gene expression at various levels. Apoptosis in vascular endothelial cells (VECs) is closely linked to numerous cardiovascular diseases, such as arteriosclerosis, thrombus formation and plaque erosion. However, studies on lncRNAs in the cardiovascular system are just beginning. And thus far, no anti-apoptosis lncRNAs have been identified in VECs. Here, we focused on the anti-apoptosis roles of lncRNAs in the serum and FGF-2 starvation-induced apoptosis of VECs. Using microarray analysis, we found a novel lncRNA LOC100129973 which acted as an apoptosis inhibitor in VECs. Through sponging miR-4707-5p and miR-4767, lncRNA LOC100129973 upregulated the expression of two apoptosis repressors gene, Apoptosis Inhibitor 5 (API5) and BCL2 like 12 (BCL2L12), and thus alleviated the serum and FGF-2 starvation-induced apoptosis in VECs. This evidence suggests that lncRNA LOC100129973 is an attractive target to improve endothelial function and for therapy of apoptosis related cardiovascular diseases. PMID:26887505

  15. Long Noncoding RNA LOC100129973 Suppresses Apoptosis by Targeting miR-4707-5p and miR-4767 in Vascular Endothelial Cells

    PubMed Central

    Lu, Wei; Huang, Shu Ya; Su, Le; Zhao, Bao Xiang; Miao, Jun Ying

    2016-01-01

    Accumulating evidence has demonstrated that long non-coding RNAs (lncRNAs) are key regulators of multiple biological processes by altering gene expression at various levels. Apoptosis in vascular endothelial cells (VECs) is closely linked to numerous cardiovascular diseases, such as arteriosclerosis, thrombus formation and plaque erosion. However, studies on lncRNAs in the cardiovascular system are just beginning. And thus far, no anti-apoptosis lncRNAs have been identified in VECs. Here, we focused on the anti-apoptosis roles of lncRNAs in the serum and FGF-2 starvation-induced apoptosis of VECs. Using microarray analysis, we found a novel lncRNA LOC100129973 which acted as an apoptosis inhibitor in VECs. Through sponging miR-4707-5p and miR-4767, lncRNA LOC100129973 upregulated the expression of two apoptosis repressors gene, Apoptosis Inhibitor 5 (API5) and BCL2 like 12 (BCL2L12), and thus alleviated the serum and FGF-2 starvation-induced apoptosis in VECs. This evidence suggests that lncRNA LOC100129973 is an attractive target to improve endothelial function and for therapy of apoptosis related cardiovascular diseases. PMID:26887505

  16. A Model of Representational Spaces in Human Cortex

    PubMed Central

    Guntupalli, J. Swaroop; Hanke, Michael; Halchenko, Yaroslav O.; Connolly, Andrew C.; Ramadge, Peter J.; Haxby, James V.

    2016-01-01

    Current models of the functional architecture of human cortex emphasize areas that capture coarse-scale features of cortical topography but provide no account for population responses that encode information in fine-scale patterns of activity. Here, we present a linear model of shared representational spaces in human cortex that captures fine-scale distinctions among population responses with response-tuning basis functions that are common across brains and models cortical patterns of neural responses with individual-specific topographic basis functions. We derive a common model space for the whole cortex using a new algorithm, searchlight hyperalignment, and complex, dynamic stimuli that provide a broad sampling of visual, auditory, and social percepts. The model aligns representations across brains in occipital, temporal, parietal, and prefrontal cortices, as shown by between-subject multivariate pattern classification and intersubject correlation of representational geometry, indicating that structural principles for shared neural representations apply across widely divergent domains of information. The model provides a rigorous account for individual variability of well-known coarse-scale topographies, such as retinotopy and category selectivity, and goes further to account for fine-scale patterns that are multiplexed with coarse-scale topographies and carry finer distinctions. PMID:26980615

  17. A Model of Representational Spaces in Human Cortex.

    PubMed

    Guntupalli, J Swaroop; Hanke, Michael; Halchenko, Yaroslav O; Connolly, Andrew C; Ramadge, Peter J; Haxby, James V

    2016-06-01

    Current models of the functional architecture of human cortex emphasize areas that capture coarse-scale features of cortical topography but provide no account for population responses that encode information in fine-scale patterns of activity. Here, we present a linear model of shared representational spaces in human cortex that captures fine-scale distinctions among population responses with response-tuning basis functions that are common across brains and models cortical patterns of neural responses with individual-specific topographic basis functions. We derive a common model space for the whole cortex using a new algorithm, searchlight hyperalignment, and complex, dynamic stimuli that provide a broad sampling of visual, auditory, and social percepts. The model aligns representations across brains in occipital, temporal, parietal, and prefrontal cortices, as shown by between-subject multivariate pattern classification and intersubject correlation of representational geometry, indicating that structural principles for shared neural representations apply across widely divergent domains of information. The model provides a rigorous account for individual variability of well-known coarse-scale topographies, such as retinotopy and category selectivity, and goes further to account for fine-scale patterns that are multiplexed with coarse-scale topographies and carry finer distinctions. PMID:26980615

  18. Specialization of reach function in human posterior parietal cortex.

    PubMed

    Vesia, Michael; Crawford, J Douglas

    2012-08-01

    Posterior parietal cortex (PPC) plays an important role in the planning and control of goal-directed action. Single-unit studies in monkeys have identified reach-specific areas in the PPC, but the degree of effector and computational specificity for reach in the corresponding human regions is still under debate. Here, we review converging evidence spanning functional neuroimaging, parietal patient and transcranial magnetic stimulation studies in humans that suggests a functional topography for reach within human PPC. We contrast reach to saccade and grasp regions to distinguish functional specificity and also to understand how these different goal-directed actions might be coordinated at the cortical level. First, we present the current evidence for reach specificity in distinct modules in PPC, namely superior parietal occipital cortex, midposterior intraparietal cortex and angular gyrus, compared to saccade and grasp. Second, we review the evidence for hemispheric lateralization (both for hand and visual hemifield) in these reach representations. Third, we review evidence for computational reach specificity in these regions and finally propose a functional framework for these human PPC reach modules that includes (1) a distinction between the encoding of reach goals in posterior-medial PPC as opposed to reach movement vectors in more anterior-lateral PPC regions, and (2) their integration within a broader cortical framework for reach, grasp and eye-hand coordination. These findings represent both a confirmation and extension of findings that were previously reported for the monkey. PMID:22777102

  19. Spatial encoding and underlying circuitry in scene-selective cortex.

    PubMed

    Nasr, Shahin; Devaney, Kathryn J; Tootell, Roger B H

    2013-12-01

    Three cortical areas (Retro-Splenial Cortex (RSC), Transverse Occipital Sulcus (TOS) and Parahippocampal Place Area (PPA)) respond selectively to scenes. However, their wider role in spatial encoding and their functional connectivity remain unclear. Using fMRI, first we tested the responses of these areas during spatial comparison tasks using dot targets on white noise. Activity increased during task performance in both RSC and TOS, but not in PPA. However, the amplitude of task-driven activity and behavioral measures of task demand were correlated only in RSC. A control experiment showed that none of these areas were activated during a comparable shape comparison task. Secondly, we analyzed functional connectivity of these areas during the resting state. Results revealed a significant connection between RSC and frontal association areas (known to be involved in perceptual decision-making). In contrast, TOS showed functional connections dorsally with the Inferior Parietal Sulcus, and ventrally with the Lateral Occipital Complex--but not with RSC and/or frontal association areas. Moreover, RSC and TOS showed differentiable functional connections with the anterior-medial and posterior-lateral parts of PPA, respectively. These results suggest two parallel pathways for spatial encoding, including RSC and TOS respectively. Only the RSC network was involved in active spatial comparisons. PMID:23872156

  20. Occipital gamma-oscillations modulated during eye movement tasks: simultaneous eye tracking and electrocorticography recording in epileptic patients.

    PubMed

    Nagasawa, Tetsuro; Matsuzaki, Naoyuki; Juhász, Csaba; Hanazawa, Akitoshi; Shah, Aashit; Mittal, Sandeep; Sood, Sandeep; Asano, Eishi

    2011-10-15

    We determined the spatio-temporal dynamics of cortical gamma-oscillations modulated during eye movement tasks, using simultaneous eye tracking and intracranial electrocorticography (ECoG) recording. Patients with focal epilepsy were instructed to follow a target moving intermittently and unpredictably from one place to another either in an instantaneous or smooth fashion during extraoperative ECoG recording. Target motion elicited augmentation of gamma-oscillations in the lateral, inferior and polar occipital regions in addition to portions of parietal and frontal regions; subsequent voluntary eye movements elicited gamma-augmentation in the medial occipital region. Such occipital gamma-augmentations could not be explained by contaminations of ocular or myogenic artifacts. The degree of gamma-augmentation was generally larger during saccade compared to pursuit trials, while a portion of the polar occipital region showed pursuit-preferential gamma-augmentations. In addition to the aforementioned eye movement task, patients were asked to read a single word popping up on the screen. Gamma-augmentation was elicited in widespread occipital regions following word presentation, while gamma-augmentation in the anterior portion of the medial occipital region was elicited by an involuntary saccade following word presentation rather than word presentation itself. Gamma-augmentation in the lateral, inferior and polar occipital regions can be explained by increased attention to a moving target, whereas gamma-augmentation in the anterior-medial occipital region may be elicited by images in the peripheral field realigned following saccades. In functional studies comparing brain activation between two tasks, eye movement patterns during tasks may need to be considered as confounding factors. PMID:21816225

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

    PubMed

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

    2013-01-01

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

  2. 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

  3. Abnormal Contrast Responses in the Extrastriate Cortex of Blindsight Patients

    PubMed Central

    Rees, Geraint; Kennard, Christopher; Bridge, Holly

    2015-01-01

    When the human primary visual cortex (V1) is damaged, the dominant geniculo-striate pathway can no longer convey visual information to the occipital cortex. However, many patients with such damage retain some residual visual function that must rely on an alternative pathway directly to extrastriate occipital regions. This residual vision is most robust for moving stimuli, suggesting a role for motion area hMT+. However, residual vision also requires high-contrast stimuli, which is inconsistent with hMT+ sensitivity to contrast in which even low-contrast levels elicit near-maximal neural activation. We sought to investigate this discrepancy by measuring behavioral and neural responses to increasing contrast in patients with V1 damage. Eight patients underwent behavioral testing and functional magnetic resonance imaging to record contrast sensitivity in hMT+ of their damaged hemisphere, using Gabor stimuli with a spatial frequency of 1 cycle/. The responses from hMT+ of the blind hemisphere were compared with hMT+ and V1 responses in the sighted hemisphere of patients and a group of age-matched controls. Unlike hMT+, neural responses in V1 tend to increase linearly with increasing contrast, likely reflecting a dominant parvocellular channel input. Across all patients, the responses in hMT+ of the blind hemisphere no longer showed early saturation but increased linearly with contrast. Given the spatiotemporal parameters used in this study and the known direct subcortical projections from the koniocellular layers of the lateral geniculate nucleus to hMT+, we propose that this altered contrast sensitivity in hMT+ could be consistent with input from the koniocellular pathway. PMID:26019336

  4. MCT8 expression in human fetal cerebral cortex is reduced in severe intrauterine growth restriction.

    PubMed

    Chan, Shiao Y; Hancox, Laura A; Martín-Santos, Azucena; Loubière, Laurence S; Walter, Merlin N M; González, Ana-Maria; Cox, Phillip M; Logan, Ann; McCabe, Christopher J; Franklyn, Jayne A; Kilby, Mark D

    2014-02-01

    The importance of the thyroid hormone (TH) transporter, monocarboxylate transporter 8 (MCT8), to human neurodevelopment is highlighted by findings of severe global neurological impairment in subjects with MCT8 (SLC16A2) mutations. Intrauterine growth restriction (IUGR), usually due to uteroplacental failure, is associated with milder neurodevelopmental deficits, which have been partly attributed to dysregulated TH action in utero secondary to reduced circulating fetal TH concentrations and decreased cerebral thyroid hormone receptor expression. We postulate that altered MCT8 expression is implicated in this pathophysiology; therefore, in this study, we sought to quantify changes in cortical MCT8 expression with IUGR. First, MCT8 immunohistochemistry was performed on occipital and parietal cerebral cortex sections obtained from appropriately grown for gestational age (AGA) human fetuses between 19 weeks of gestation and term. Secondly, MCT8 immunostaining in the occipital cortex of stillborn IUGR human fetuses at 24-28 weeks of gestation was objectively compared with that in the occipital cortex of gestationally matched AGA fetuses. Fetuses demonstrated widespread MCT8 expression in neurons within the cortical plate and subplate, in the ventricular and subventricular zones, in the epithelium of the choroid plexus and ependyma, and in microvessel wall. When complicated by IUGR, fetuses showed a significant fivefold reduction in the percentage area of cortical plate immunostained for MCT8 compared with AGA fetuses (P<0.05), but there was no significant difference in the proportion of subplate microvessels immunostained. Cortical MCT8 expression was negatively correlated with the severity of IUGR indicated by the brain:liver weight ratios (r(2)=0.28; P<0.05) at post-mortem. Our results support the hypothesis that a reduction in MCT8 expression in the IUGR fetal brain could further compromise TH-dependent brain development. PMID:24204008

  5. 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

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

    PubMed

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

    2014-11-01

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

  7. The Gravettian occipital bone from the site of Malladetes (Barx, Valencia, Spain).

    PubMed

    Arsuaga, Juan Luis; Villaverde, Valentín; Quam, Rolf; Gracia, Ana; Lorenzo, Carlos; Martínez, Ignacio; Carretero, José-Miguel

    2002-09-01

    The juvenile occipital bone from the site of Malladetes in Valencia (Spain) is described and compared with other European Pleistocene representatives of the genus Homo. This specimen derives from a Gravettian cultural context and has been AMS radiocarbon-dated to 25,120 +/- 240 years BP. As such, it provides evidence on early modern human anatomy from the Central Mediterranean region of the Iberian peninsula. The clear evidence for a late survival of Neandertals in southern Iberia, has led to considerable debate surrounding the biological and cultural interactions between these Pleistocene humans and their early modern human successors, and it is within this context that the Malladetes specimen represents an important contribution to the discussion. The recently discovered Upper Paleolithic infant from the site of Lagar Velho in Portugal is said to show a mosaic of Neandertal and early modern human characteristics throughout the skeleton and is argued to represent the strongest evidence yet recovered in favor of hybridization between these two Pleistocene populations. Our analysis of the Malladetes occipital, however, reveals no evidence of Neandertal genetic influence. PMID:12234549

  8. Distinctive Menkes disease variant with occipital horns: delineation of natural history and clinical phenotype.

    PubMed

    Proud, V K; Mussell, H G; Kaler, S G; Young, D W; Percy, A K

    1996-10-01

    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, and 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 [Kaler et al., 1994: Nat Genet 18:195-202]. 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. PMID:8914740

  9. Occipital nerve stimulation for the treatment of intractable chronic migraine headache: ONSTIM feasibility study

    PubMed Central

    Saper, Joel R; Dodick, David W; Silberstein, Stephen D; McCarville, Sally; Sun, Mark; Goadsby, Peter J

    2011-01-01

    Background: Medically intractable chronic migraine (CM) is a disabling illness characterized by headache ?15 days per month. Methods: A multicenter, randomized, blinded, controlled feasibility study was conducted to obtain preliminary safety and efficacy data on occipital nerve stimulation (ONS) in CM. Eligible subjects received an occipital nerve block, and responders were randomized to adjustable stimulation (AS), preset stimulation (PS) or medical management (MM) groups. Results: Seventy-five of 110 subjects were assigned to a treatment group; complete diary data were available for 66. A responder was defined as a subject who achieved a 50% or greater reduction in number of headache days per month or a three-point or greater reduction in average overall pain intensity compared with baseline. Three-month responder rates were 39% for AS, 6% for PS and 0% for MM. No unanticipated adverse device events occurred. Lead migration occurred in 12 of 51 (24%) subjects. Conclusion: The results of this feasibility study offer promise and should prompt further controlled studies of ONS in CM. PMID:20861241

  10. [Occipital seizures with electroencephalographic alterations as the initial manifestation of diabetes mellitus].

    PubMed

    Martínez, María Durán; Megías, Susana Monereo

    2009-12-01

    Focal motor seizures are common in nonketotic hyperglycemia but occipital seizures as the initial symptom of hyperglycemia are exceptional. Sporadic electroencephalographic description has rarely been reported. A 56-year-old man presented to the emergency department with a 4-day history of intermittent, 30-minute episodes of flashing lights (blue-yellow color), 3-4 times per day in his left lower temporal visual field. His past medical history was significant for hypercholesterolemia and hypertension. The results of the ophthalmology examination were normal. When asked, the patient reported polyuria, polydipsia and weight gain for the previous 4 months. His general state was good and no other neurological symptoms were present. Among the laboratory tests, non-ketonic hyperglycemia of 339 mg/dl and mild plasma hyperosmolarity of 302 mOsm/kg were found. The results of visual campimetry were normal. Brain magnetic resonance imaging showed minimal alterations unrelated to the visual symptoms. An electrographic seizure in the right occipital region associated with visual symptoms was recorded. The patient was treated with hydration and insulin and was completely asymptomatic after 48 hours. PMID:20114016

  11. Imaging of Atlanto-Occipital and Atlantoaxial Traumatic Injuries: What the Radiologist Needs to Know.

    PubMed

    Riascos, Roy; Bonfante, Eliana; Cotes, Claudia; Guirguis, Mary; Hakimelahi, Reza; West, Clark

    2015-01-01

    Approximately one-third of all cervical spine injuries involve the craniocervical junction (CCJ). Composed of the occiput and the first two cervical vertebrae, this important anatomic landmark, in conjunction with an intricate ligamentous complex, is essential to maintaining the stability of the cervical spine. The atlantoaxial joint is the most mobile portion of the spine, predominantly relying on the ligamentous framework for stability at that level. As acute onsite management of trauma patients continues to improve, CCJ injuries, which often lead to death onsite where the injury occurred, are increasingly being encountered in the emergency department. Understanding the anatomy of the CCJ is crucial in properly evaluating the cervical spine, allowing the radiologist to assess its stability in the trauma setting. The imaging findings of important CCJ injuries, such as atlanto-occipital dissociation, occipital condyle fractures, atlas fractures with transverse ligament rupture, atlantoaxial distraction, and traumatic rotatory subluxation, are important to recognize in the acute setting, often dictating patient management. Thin-section multidetector computed tomography with sagittal and coronal reformats is the study of choice in evaluating the extent of injury, allowing the radiologist to thoroughly evaluate the stability of the cervical spine. Furthermore, magnetic resonance (MR) imaging is increasingly being used to evaluate the spinal soft tissues and ligaments, and to identify associated spinal cord injury, if present. MR imaging is also indicated in patients whose neurologic status cannot be evaluated within 48 hours of injury. . PMID:26562241

  12. 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.

  13. Enhanced Awareness Followed Reversible Inhibition of Human Visual Cortex: A Combined TMS, MRS and MEG Study

    PubMed Central

    Allen, Christopher P. G.; Dunkley, Benjamin T.; Muthukumaraswamy, Suresh D.; Edden, Richard; Evans, C. John; Sumner, Petroc; Singh, Krish D.; Chambers, Christopher D.

    2014-01-01

    This series of experiments investigated the neural basis of conscious vision in humans using a form of transcranial magnetic stimulation (TMS) known as continuous theta burst stimulation (cTBS). Previous studies have shown that occipital TMS, when time-locked to the onset of visual stimuli, can induce a phenomenon analogous to blindsight in which conscious detection is impaired while the ability to discriminate ‘unseen’ stimuli is preserved above chance. Here we sought to reproduce this phenomenon using offline occipital cTBS, which has been shown to induce an inhibitory cortical aftereffect lasting 45–60 minutes. Contrary to expectations, our first experiment revealed the opposite effect: cTBS enhanced conscious vision relative to a sham control. We then sought to replicate this cTBS-induced potentiation of consciousness in conjunction with magnetoencephalography (MEG) and undertook additional experiments to assess its relationship to visual cortical excitability and levels of the inhibitory neurotransmitter γ-aminobutyric acid (GABA; via magnetic resonance spectroscopy, MRS). Occipital cTBS decreased cortical excitability and increased regional GABA concentration. No significant effects of cTBS on MEG measures were observed, although the results provided weak evidence for potentiation of event related desynchronisation in the β band. Collectively these experiments suggest that, through the suppression of noise, cTBS can increase the signal-to-noise ratio of neural activity underlying conscious vision. We speculate that gating-by-inhibition in the visual cortex may provide a key foundation of consciousness. PMID:24956195

  14. Suppression of ponto-geniculo-occipital waves by neurotoxic lesions of pontine caudo-lateral peribrachial cells.

    PubMed

    Datta, S; Hobson, J A

    1995-08-01

    Ponto-geniculo-occipital waves precede rapid eye movement sleep and play an important role in triggering and maintaining rapid eye movement sleep. Ponto-geniculo-occipital waves have been implicated in several important functions such as sensorimotor integration, learning, cognition, development of the visual system, visual hallucination, and startle response. Peribrachial area neurons have long been thought to play a key role in the triggering of ponto-geniculo-occipital wave. However, the exact location within the peribrachial area for triggering pontine ponto-geniculo-occipital wave has not been unequivocally demonstrated. In an attempt to address this issue, kainic acid was microinjected (1.0 micrograms) unilaterally into the caudo-lateral peribrachial area of four cats in order to destroy the cell bodies located in that region and thus to study the effects of their destruction upon waking-sleep states and ponto-geniculo-occipital waves. The kainic acid produced a small spherical area of nerve cell loss and/or gliosis centered on the stereotaxic coordinates of P: 4.0, L: 4.5, and H: -2.5. The maximum diameter of that spherical area of cell loss was 0.9 mm. Unilateral lesioning of the caudo-lateral peribrachial area decreased ponto-geniculo-occipital waves during rapid eye movement sleep by 85% ipsi-laterally and 15% contralaterally in the lateral geniculate body without significantly changing the amounts of time spent in wake, slow-wave sleep, and rapid eye movement sleep. These results suggest that the caudo-lateral peribrachial area cells are critical to the genesis of ponto-geniculo-occipital waves, and provide compelling evidence that the different parts of the peribrachial area have quite different roles in the generation of discrete rapid eye movement sleep signs. We propose that caudo-lateral peribrachial cells exert an excitatory influence on rostral peribrachial cells, which then directly activate the ponto-geniculo-occipital waves that are recorded in the lateral geniculate body. Results of this study are not only important to understand the mechanisms generating ponto-geniculo-occipital waves but also could be used as an experimental tool to study the functions of this wave. PMID:7675196

  15. Vestibular function in the temporal and parietal cortex: distinct velocity and inertial processing pathways

    PubMed Central

    Ventre-Dominey, Jocelyne

    2014-01-01

    A number of behavioral and neuroimaging studies have reported converging data in favor of a cortical network for vestibular function, distributed between the temporo-parietal cortex and the prefrontal cortex in the primate. In this review, we focus on the role of the cerebral cortex in visuo-vestibular integration including the motion sensitive temporo-occipital areas i.e., the middle superior temporal area (MST) and the parietal cortex. Indeed, these two neighboring cortical regions, though they both receive combined vestibular and visual information, have distinct implications in vestibular function. In sum, this review of the literature leads to the idea of two separate cortical vestibular sub-systems forming (1) a velocity pathway including MST and direct descending pathways on vestibular nuclei. As it receives well-defined visual and vestibular velocity signals, this pathway is likely involved in heading perception and rapid top-down regulation of eye/head coordination and (2) an inertial processing pathway involving the parietal cortex in connection with the subcortical vestibular nuclei complex responsible for velocity storage integration. This vestibular cortical pathway would be implicated in high-order multimodal integration and cognitive functions, including world space and self-referential processing. PMID:25071481

  16. Effects of visual cortex activation on the nociceptive blink reflex in healthy subjects.

    PubMed

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

  17. Cognition without Cortex.

    PubMed

    Güntürkün, Onur; Bugnyar, Thomas

    2016-04-01

    Assumptions on the neural basis of cognition usually focus on cortical mechanisms. Birds have no cortex, but recent studies in parrots and corvids show that their cognitive skills are on par with primates. These cognitive findings are accompanied by neurobiological discoveries that reveal avian and mammalian forebrains are homologous, and show similarities in connectivity and function down to the cellular level. But because birds have a large pallium, but no cortex, a specific cortical architecture cannot be a requirement for advanced cognitive skills. During the long parallel evolution of mammals and birds, several neural mechanisms for cognition and complex behaviors may have converged despite an overall forebrain organization that is otherwise vastly different. PMID:26944218

  18. Motor cortex inhibition

    PubMed Central

    Isaacs, K.M.; Augusta, M.; MacNeil, L.K.; Mostofsky, S.H.

    2011-01-01

    Objective: Attention-deficit/hyperactivity disorder (ADHD) is a childhood-onset behavioral diagnosis in which children often fail to meet age norms in development of motor control, particularly timed repetitive and sequential movements, motor overflow, and balance. The neural substrate of this motor delay may include mechanisms of synaptic inhibition in or adjacent to the motor cortex. The primary objective of this study was to determine whether transcranial magnetic stimulation (TMS)–evoked measures, particularly short interval cortical inhibition (SICI), in motor cortex correlate with the presence and severity of ADHD in childhood as well as with commonly observed delays in motor control. Methods: In this case-control study, behavioral ratings, motor skills, and motor cortex physiology were evaluated in 49 children with ADHD (mean age 10.6 years, 30 boys) and 49 typically developing children (mean age 10.5 years, 30 boys), all right-handed, aged 8–12 years. Motor skills were evaluated with the Physical and Neurological Examination for Subtle Signs (PANESS) and the Motor Assessment Battery for Children version 2. SICI and other physiologic measures were obtained using TMS in the left motor cortex. Results: In children with ADHD, mean SICI was reduced by 40% (p < 0.0001) and less SICI correlated with higher ADHD severity (r = −0.52; p = 0.002). Mean PANESS motor development scores were 59% worse in children with ADHD (p < 0.0001). Worse PANESS scores correlated modestly with less SICI (r = −.30; p = 0.01). Conclusion: Reduced TMS-evoked SICI correlates with ADHD diagnosis and symptom severity and also reflects motor skill development in children. PMID:21321335

  19. 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

  20. Direct control of visual perception with phase-specific modulation of posterior parietal cortex.

    PubMed

    Jaegle, Andrew; Ro, Tony

    2014-02-01

    We examined the causal relationship between the phase of alpha oscillations (9-12 Hz) and conscious visual perception using rhythmic TMS (rTMS) while simultaneously recording EEG activity. rTMS of posterior parietal cortex at an alpha frequency (10 Hz), but not occipital or sham rTMS, both entrained the phase of subsequent alpha oscillatory activity and produced a phase-dependent change on subsequent visual perception, with lower discrimination accuracy for targets presented at one phase of the alpha oscillatory waveform than for targets presented at the opposite phase. By extrinsically manipulating the phase of alpha before stimulus presentation, we provide direct evidence that the neural circuitry in the parietal cortex involved with generating alpha oscillations plays a causal role in determining whether or not a visual stimulus is successfully perceived. PMID:24116843

  1. The cortex is in overall control of ‘voluntary' eye movement

    PubMed Central

    Pouget, P

    2015-01-01

    The neural circuits that control eye movements are complex and distributed in brainstem, basal ganglia, cerebellum, and multiple areas of cortex. The anatomical function of the substrates implicated in eye movements has been studied for decades in numerous countries, laboratories, and clinics. The modest goal of this brief review is twofold. (1) To present a focused overview of the knowledge about the role of the cerebral cortex in voluntary control of eye movements. (2) To very briefly mention two findings showing that the accepted hierarchy between the frontal and the occipital sensory areas involved in sensory–motor transformation might not be so trivial to reconcile, and to interpret in the context of eye movement command. This presentation has been part of the 44th Cambridge Ophthalmological Symposium, on ocular motility, 3 September 2014 to 5 November 2014. PMID:25475239

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

    PubMed

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

    2015-10-01

    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

  3. 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

  4. 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.

  5. Interim Measures Report for the Headquarters Building Area Location of Concern (LOC) 2E East SWMU 104 John F. Kennedy Space Center, Florida

    NASA Technical Reports Server (NTRS)

    Sager, Eric D.

    2016-01-01

    The Hazardous and Solid Waste Amendment portion of the National Aeronautics and Space Administration (NASA) Resource Conservation and Recovery Act (RCRA) Permit issued by the Florida Department of Environmental Protection (FDEP), requires identification and evaluation of all known Solid Waste Management Units (SWMUs) and Locations of Concern (LOCs) located on Kennedy Space Center (KSC) property. The KSC Headquarters Building Area (KHQA) has been identified as SWMU 104 under KSC's RCRA Program. This report summarizes the Interim Measure (IM) conducted by Geosyntec Consultants (Geosyntec) for NASA under Indefinite Delivery Indefinite Quantity Contract NNK12CA13B at the KHQA to mitigate potential exposure to polychlorinated biphenyl (PCB)-affected media at the eastern side of LOC 2E. The IM activities were conducted in June and July 2015 to remediate PCBs above the FDEP Residential Direct-Exposure (R-) Soil Cleanup Target Level (SCTL) of 0.5 milligram per kilogram (mg/kg) established by Chapter 62-777, Florida Administrative Code. The IM was performed in accordance with the IM Work Plan (IMWP) approved by the FDEP, dated August 2012. IM activities were conducted in accordance with the KSC Generic PCB Work Plan (NASA 2007).

  6. CX-516 Cortex pharmaceuticals.

    PubMed

    Danysz, Wojciech

    2002-07-01

    CX-516 is one of a series of AMPA modulators under development by Cortex, in collaboration with Shire and Servier, for the potential treatment of Alzheimer's disease (AD), schizophrenia and mild cognitive impairment (MCI) [234221]. By June 2001, CX-516 was in phase II trials for both schizophrenia and attention deficit hyperactivity disorder (ADHD) [412513]. A phase II trial in fragile X syndrome and autism was expected to start in May 2002 [449861]. In October 2001, Cortex was awarded a Phase II SBIR grant of $769,818 from the National Institutes of Mental Health to investigate the therapeutic potential of AMPAkines in schizophrenia. This award was to support a phase IIb study of CX-516 as a combination therapy in schizophrenia patients concomitantly treated with olanzapine. The trial was to enroll 80 patients and employ a randomized, double-blind, placebo-controlled design in which the placebo group was to receive olanzapine plus placebo and the active group was to receive olanzapine plus CX-516 [425982]. In April 2000, Shire and Cortex signed an option agreement in which Shire was to evaluate CX-516for the treatment of ADHD. Under the terms of the agreement, Shire would undertake a double-blind, placebo-controlled evaluation of CX-516 involving ADHD patients. If the study proved effective, Shire would have the right to convert its option into an exclusive worldwide license for the AMPAkines for ADHD under a development and licensing agreement. Should Shire elect to execute this agreement, Shire would bear all future developmental costs [363618]. By February 2002, Cortex and Servier had revealed their intention to begin enrolment for an international study of an AMPAkine compound as a potential treatment for MCI in the near future. Assuming enrollment proceeded as anticipated, results were expected during the second quarter of 2003 [439301]. By May 2002, phase II trials were underway [450134]. In March 2002, Cortex was awarded extended funding under the University of California BioSTAR projectfor the research project: 'Ampakine modulation of brain neurotrophin expression: a novel therapeutic strategy'. This funding was expected to amount to $193,000 over a two-year period [444872]. PMID:12186271

  7. A Functional Neuroimaging Study of Sound Localization: Visual Cortex Activity Predicts Performance in Early-Blind Individuals

    PubMed Central

    Gougoux, Frédéric; Zatorre, Robert J; Lassonde, Maryse; Voss, Patrice

    2005-01-01

    Blind individuals often demonstrate enhanced nonvisual perceptual abilities. However, the neural substrate that underlies this improved performance remains to be fully understood. An earlier behavioral study demonstrated that some early-blind people localize sounds more accurately than sighted controls using monaural cues. In order to investigate the neural basis of these behavioral differences in humans, we carried out functional imaging studies using positron emission tomography and a speaker array that permitted pseudo-free-field presentations within the scanner. During binaural sound localization, a sighted control group showed decreased cerebral blood flow in the occipital lobe, which was not seen in early-blind individuals. During monaural sound localization (one ear plugged), the subgroup of early-blind subjects who were behaviorally superior at sound localization displayed two activation foci in the occipital cortex. This effect was not seen in blind persons who did not have superior monaural sound localization abilities, nor in sighted individuals. The degree of activation of one of these foci was strongly correlated with sound localization accuracy across the entire group of blind subjects. The results show that those blind persons who perform better than sighted persons recruit occipital areas to carry out auditory localization under monaural conditions. We therefore conclude that computations carried out in the occipital cortex specifically underlie the enhanced capacity to use monaural cues. Our findings shed light not only on intermodal compensatory mechanisms, but also on individual differences in these mechanisms and on inhibitory patterns that differ between sighted individuals and those deprived of vision early in life. PMID:15678166

  8. The Temporal Dynamics of Implicit Processing of Non-Letter, Letter, and Word-Forms in the Human Visual Cortex

    PubMed Central

    Appelbaum, Lawrence G.; Liotti, Mario; Perez, Ricardo; Fox, Sarabeth P.; Woldorff, Marty G.

    2009-01-01

    The decoding of visually presented line segments into letters, and letters into words, is critical to fluent reading abilities. Here we investigate the temporal dynamics of visual orthographic processes, focusing specifically on right hemisphere contributions and interactions between the hemispheres involved in the implicit processing of visually presented words, consonants, false fonts, and symbolic strings. High-density EEG was recorded while participants detected infrequent, simple, perceptual targets (dot strings) embedded amongst a of character strings. Beginning at 130 ms, orthographic and non-orthographic stimuli were distinguished by a sequence of ERP effects over occipital recording sites. These early latency occipital effects were dominated by enhanced right-sided negative-polarity activation for non-orthographic stimuli that peaked at around 180 ms. This right-sided effect was followed by bilateral positive occipital activity for false-fonts, but not symbol strings. Moreover the size of components of this later positive occipital wave was inversely correlated with the right-sided ROcc180 wave, suggesting that subjects who had larger early right-sided activation for non-orthographic stimuli had less need for more extended bilateral (e.g., interhemispheric) processing of those stimuli shortly later. Additional early (130–150 ms) negative-polarity activity over left occipital cortex and longer-latency centrally distributed responses (>300 ms) were present, likely reflecting implicit activation of the previously reported ‘visual-word-form’ area and N400-related responses, respectively. Collectively, these results provide a close look at some relatively unexplored portions of the temporal flow of information processing in the brain related to the implicit processing of potentially linguistic information and provide valuable information about the interactions between hemispheres supporting visual orthographic processing. PMID:20046826

  9. Computer-tomographic (CT) studies and anthropological measurements in patients with atlanto-occipital fusion.

    PubMed

    Sharma, S; Gupta, S; Kalla, A K; Khanna, S; Singh, I P; Vogel, F

    1991-12-01

    Computer tomographic (CT) studies and anthropological measurements were performed in individuals showing complete or partial atlanto-occipital fusion. In 13 patients and 13 matched controls all measurements excepting head length and head breadth gave smaller, and in some instances significantly smaller values in the patients. The two head measurements, on the other hand, turned out to be somewhat, though not significantly larger. This suggested a certain amount of hydrocephalus internus. Computer-tomographic (CT) studies in 11 patients and 9 controls gave some--not very clearcut--evidence in favor of this hypothesis. Moreover, some other mild anomalies such as prominent and dilated sulci and cisterns were observed in 9 of 11 patients and in 3 of 9 controls (P1 one tailed = 0.0399). PMID:1793258

  10. 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

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

    PubMed

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

    2015-11-01

    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

  12. The Occipital Place Area Is Causally Involved in Representing Environmental Boundaries during Navigation.

    PubMed

    Julian, Joshua B; Ryan, Jack; Hamilton, Roy H; Epstein, Russell A

    2016-04-25

    Thirty years of research suggests that environmental boundaries-e.g., the walls of an experimental chamber or room-exert powerful influence on navigational behavior, often to the exclusion of other cues [1-9]. Consistent with this behavioral work, neurons in brain structures that instantiate spatial memory often exhibit firing fields that are strongly controlled by environmental boundaries [10-15]. Despite the clear importance of environmental boundaries for spatial coding, however, a brain region that mediates the perception of boundary information has not yet been identified. We hypothesized that the occipital place area (OPA), a scene-selective region located near the transverse occipital sulcus [16], might provide this perceptual source by extracting boundary information from visual scenes during navigation. To test this idea, we used transcranial magnetic stimulation (TMS) to interrupt processing in the OPA while subjects performed a virtual-reality memory task that required them to learn the spatial locations of test objects that were either fixed in place relative to the boundary of the environment or moved in tandem with a landmark object. Consistent with our prediction, we found that TMS to the right OPA impaired spatial memory for boundary-tethered, but not landmark-tethered, objects. Moreover, this effect was found when the boundary was defined by a wall, but not when it was defined by a marking on the ground. These results show that the OPA is causally involved in boundary-based spatial navigation and suggest that the OPA is the perceptual source of the boundary information that controls navigational behavior. PMID:27020742

  13. Occipital plagiocephaly: deformation or lambdoid synostosis? I. Morphometric analysis and results of unilateral lambdoid craniectomy.

    PubMed

    Dias, M S; Klein, D M; Backstrom, J W

    1996-01-01

    Between 1987 and 1992, 30 infants aged 1.4-13 months (mean 7.3 months) underwent unilateral lambdoid strip craniectomy at the Children's Hospital of Buffalo for occipital plagiocephaly. Males outnumbered females (22:8) and right-sided occipital flattening was significantly more common than left-sided flattening (25:5). The deformity was noticed at an average age of 3.2 months; 16% of the infants had an asymmetry at birth. Positional preferences (a distinct tendency to lie preferentially on the back, in most cases with the head turned to the ipsilateral side) were described in 79% of infants for whom this information was available, and torticollis was present in 10%. Pre- and post-operative CT scans were analyzed using several morphometric measurements. Asymmetries were measured between the flattened and contralateral sides, both posteriorly and anteriorly, using a translucent grid placed over the CT slice showing maximum asymmetry. The average maximum asymmetry between the flattened and contralateral sides was 24% posteriorly and 16% anteriorly. Significant improvements were seen postoperatively, with both anterior and posterior asymmetries improving by an average of one third (p < 0.05). However, when compared with CT scans from a control group of infants without synostosis, the operated group showed persistent and significant asymmetries postoperatively. The morphometric measurements described allow an objective and reproducible means of assessing the results of various treatments for this disorder. The improvements following unilateral lambdoid craniectomy are difficult to interpret in isolation; we suggest that future efforts be directed toward similarly assessing the results of both nonoperative treatments such as positional changes and molding helmets, and more aggressive surgical treatments that have been advocated for this disorder. PMID:8841075

  14. 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

  15. 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

  16. Word or word-like? Dissociating orthographic typicality from lexicality in the left occipito-temporal cortex.

    PubMed

    Woollams, Anna M; Silani, Giorgia; Okada, Kayoko; Patterson, Karalyn; Price, Cathy J

    2011-04-01

    Prior lesion and functional imaging studies have highlighted the importance of the left ventral occipito-temporal (LvOT) cortex for visual word recognition. Within this area, there is a posterior-anterior hierarchy of subregions that are specialized for different stages of orthographic processing. The aim of the present fMRI study was to dissociate the effects of subword orthographic typicality (e.g., cider [high] vs. cynic [low]) from the effect of lexicality (e.g., pollen [word] vs. pillen [pseudoword]). We therefore orthogonally manipulated the orthographic typicality of written words and pseudowords (nonwords and pseudohomophones) in a visual lexical decision task. Consistent with previous studies, we identified greater activation for pseudowords than words (i.e., an effect of lexicality) in posterior LvOT cortex. In addition, we revealed higher activation for atypical than typical strings, irrespective of lexicality, in a left inferior occipital region that is posterior to LvOT cortex. When lexical decisions were made more difficult in the context of pseudohomophone foils, left anterior temporal activation also increased for atypical relative to typical strings. The latter finding agrees with the behavior of patients with progressive anterior temporal lobe degeneration, who have particular difficulty recognizing words with atypical orthography. The most novel outcome of this study is that, within a distributed network of regions supporting orthographic processing, we have identified a left inferior occipital region that is particularly sensitive to the typicality of subword orthographic patterns. PMID:20429854

  17. Image-Guided Stereotactic Body Radiotherapy for Lung Tumors Using BodyLoc With Tomotherapy: Clinical Implementation and Set-Up Accuracy

    SciTech Connect

    Zhou Jining Uhl, Barry; Dewitt, Kelly; Young, Mark; Taylor, Brian; Fei Dingyu; Lo, Y-C

    2010-04-01

    We investigated the use of a BodyLoc immobilization and stereotactic localization device combined with TomoTherapy megavoltage CT (MVCT) in lung stereotactic body radiotherapy (SBRT) to reduce set-up uncertainty and treatment time. Eight patients treated with 3-5 fractions of SBRT were retrospectively analyzed. A BodyLoc localizer was used in both CT simulation for localization and the initial patient treatment set-up. Patients were immobilized with a vacuum cushion on the back and a thermoplastic body cast on the anterior body. Pretreatment MVCT from the TomoTherapy unit was fused with the planning kilovoltage CT (KVCT) before each fraction of treatment to determine interfractional set-up error. The comparison of two MVCTs during a fraction of treatment resulted in the intrafractional uncertainty of the treatment. A total of 224 target isocenter shifts were analyzed to assess these inter- and intrafractional tumor motions. We found that for interfractional shifts, the mean set-up errors and standard deviations were -1.1 {+-} 2.8 mm, -2.5 {+-} 8.7 mm, and 4.1 {+-} 2.6 mm, for lateral, longitudinal, and vertical variation, respectively; the mean setup rotational variation was -0.3 {+-} 0.7 deg.; and the maximum motion was 13.5 mm in the longitudinal direction. For intrafractional shifts, the mean set-up errors and standard deviations were -0.1 {+-} 0.7 mm, -0.3 {+-} 2.0 mm, and 0.5 {+-} 1.1 mm for the lateral, longitudinal, and vertical shifts, respectively; the mean rotational variation was 0.1 {+-} 0.2 deg.; and the maximum motion was 3.8 mm in the longitudinal direction. There was no correlation among patient characteristics, set-up uncertainties, and isocenter shifts, and the interfractional set-up uncertainties were larger than the intrafractional isocenter shift. The results of this study suggested that image-guided stereotactic body radiotherapy using the BodyLoc immobilization system with TomoTherapy can improve treatment accuracy.

  18. Neurocontrol in sensory cortex

    NASA Astrophysics Data System (ADS)

    Ritt, Jason; Nandi, Anirban; Schroeder, Joseph; Ching, Shinung

    Technology to control neural ensembles is rapidly advancing, but many important challenges remain in applications, such as design of controls (e.g. stimulation patterns) with specificity comparable to natural sensory encoding. We use the rodent whisker tactile system as a model for active touch, in which sensory information is acquired in a closed loop between feedforward encoding of sensory information and feedback guidance of sensing motions. Motivated by this system, we present optimal control strategies that are tailored for underactuation (a large ratio of neurons or degrees of freedom to stimulation channels) and limited observability (absence of direct measurement of the system state), common in available stimulation technologies for freely behaving animals. Using a control framework, we have begun to elucidate the feedback effect of sensory cortex activity on sensing in behaving animals. For example, by optogenetically perturbing primary sensory cortex (SI) activity at varied timing relative to individual whisker motions, we find that SI modulates future sensing behavior within 15 msec, on a whisk by whisk basis, changing the flow of incoming sensory information based on past experience. J.T.R. and S.C. hold Career Awards at the Scientific Interface from the Burroughs Wellcome Fund.

  19. Lower Trapezius Flap for Reconstruction of Posterior Scalp and Neck Defects after Complex Occipital-Cervical Surgeries.

    PubMed

    Zenga, Joseph; Sharon, Jeffrey D; Santiago, Paul; Nussenbaum, Brian; Haughey, Bruce H; Fox, Ida K; Myckatyn, Terence M; Diaz, Jason A; Chicoine, Michael R

    2015-09-01

    Objectives To review the indications, techniques, and outcomes for a series of patients in whom the lower trapezius flaps was used for repair of complex posterior scalp and neck defects after posterior occipital-cervical surgeries. Design Retrospective case series. Setting Tertiary academic hospital. Participants A retrospective review of cases that required complex occipital-cervical repair was performed to identify patients who underwent reconstruction using the lower trapezius flap. Data collected included demographics, clinical presentations, surgical anatomy, operative techniques, and outcomes with review of the pertinent literature. Outcomes Nine patients who underwent reconstruction using the lower trapezius flap were identified. Prior surgical interventions included five complex tumor resections, two patients with multiple instrumented cervical spine surgeries, one patient with a craniotomy for attempted extracranial to intracranial arterial bypass for a basilar aneurysm repair, and a posterior occipital-cervical decompression after trauma. During the median follow-up period of 7 months, all nine single-stage reconstructions resulted in successful healing without major surgical complications. Conclusion Lower trapezius island flaps provide a reliable option for the reconstruction of complex scalp and neck defects that develop after complex occipital-cervical surgeries. PMID:26401483

  20. 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

  1. DECREASED OCCIPITAL CORTICAL GLUTAMATE LEVELS IN RESPONSE TO SUCCESSFUL COGNITIVE-BEHAVIORAL THERAPY AND PHARMACOTHERAPY FOR MAJOR DEPRESSIVE DISORDER

    PubMed Central

    Abdallah, Chadi G.; Niciu, Mark J.; Fenton, Lisa R.; Fasula, Madonna K.; Jiang, Lihong; Black, Anne; Rothman, Douglas L.; Mason, Graeme F.; Sanacora, Gerard

    2014-01-01

    BACKGROUND Previous studies have demonstrated that antidepressant medication and electroconvulsive therapy increase occipital cortical GABA in major depressive disorder (MDD), but, a small pilot study failed to show a similar effect of cognitive behavioral therapy (CBT) on occipital GABA. In light of these findings we sought to determine if baseline GABA levels predict treatment response and to broaden the analysis to other metabolites and neurotransmitters in this larger study. METHODS 40 MDD outpatients received baseline 1H-MRS, and 30 subjects completed both pre- and post-CBT 1H-MRS. Nine CBT non-responders completed an open-label medication phase followed by an additional/third 1H-MRS. The magnitude of treatment response was correlated with occipital amino acid neurotransmitter levels. RESULTS Baseline GABA did not predict treatment outcome. Furthermore, there was no significant effect of CBT on GABA levels. However, we found a significant group x time interaction (F(1,28) = 6.30, p = 0.02), demonstrating reduced glutamate in CBT responders with no significant glutamate change in CBT non-responders. CONCLUSIONS These findings corroborate the lack of effect of successful CBT on occipital cortical GABA levels in a larger sample. A reduction in glutamate levels following treatment, on the other hand, correlated with successful CBT and antidepressant medication response. Based on this finding and other reports, decreased occipital glutamate may be an antidepressant response biomarker. Healthy control comparator and non-intervention groups may shed light on the sensitivity and specificity of these results. PMID:25116726

  2. Clinical and Anatomical Features as well as Pathological Conditions of Surgically Treated Adult Patients with Occipitalization of the Atlas

    PubMed Central

    Shimizu, Takachika; Fueki, Keisuke; Ino, Masatake; Toda, Naofumi; Tanouchi, Tetsu; Manabe, Nodoka

    2016-01-01

    Background This paper intends to clarify clinical and anatomical features as well as pathological conditions of surgically treated adult patients with occipitalization of the atlas. Methods The authors reviewed 12 consecutive adult patients with occipitalization of the atlas who underwent surgery for myleopathy in our hospital. Mainly using preoperative computed tomography and three-dimensional computed tomography angiography, we investigated their anomalies of the osseous structures and vertebral artery at the cervical spine including the craniovertebral junction (CVJ). We also developed a new classification system for occipitalization of the atlas. Results Atlantoaxial subluxation (AAS) was detected in 9 patients (75%). The condition of AAS was irreducible in 7 patients. Among these 7 patients, deformity at the lateral atlantoaxial joints was detected in 2 patients. C2-3 fusion was detected in 6 patients (67%) among 9 patients with AAS. Anomalies of the VA were detected in 11 patients (92%). Occipitalization of the atlas was classified into three types according to their pathological conditions. In type 1 (2 patients) the medial atlantoaxial joint is semi-dislocated and the lateral atlantoaxial joints are severely deformed. Type 2 (7 patients) exhibits AAS but the lateral atlantoaxial joints are not deformed. Type 3 (3 patients) is not associated with AAS and therefore does not exhibit osseous stenosis at the CVJ. In type 3 the myelopathy was caused by another coexisting condition. Conclusions Occipitalization of the atlas is classified into three types. The main pathological condition in both types 1 and 2 is AAS. Reduction of AAS is essential in both; however, reduction of AAS in type 1 is more technically demanding than in type 2. The pathological conditions of type 3 are completely different from those of the others, so an accurate diagnosis must be made. The new classification system is a useful guide for surgeons when planning surgical strategies. PMID:26913225

  3. Activity of the human visual cortex measured non-invasively by diffusing-wave spectroscopy

    NASA Astrophysics Data System (ADS)

    Jaillon, Franck; Li, Jun; Dietsche, Gregor; Elbert, Thomas; Gisler, Thomas

    2007-05-01

    Activity of the human visual cortex, elicited by steady-state flickering at 8Hz, is non-invasively probed by multi-speckle diffusingwave spectroscopy (DWS). Parallel detection of the intensity fluctuations of statistically equivalent, but independent speckles allows to resolve stimulation-induced changes in the field autocorrelation of multiply scattered light of less than 2%. In a group of 9 healthy subjects we find a faster decay of the field autocorrelation function during the stimulation periods for data measured with a long-distance probe (30mm source-receiver distance) at 2 positions over the occipital cortex (t-test: t(8) = -2.672, p = 0.028 < 0.05 for position 1, t(8) = -2.874, p = 0.021 < 0.05 for position 2). In contrast, no statistically significant change is seen when a short-distance probe (16mm source-receiver distance) is used (t-test: t(8) = -2.043, p = 0.075 > 0.05 for position 1, t(8) = -2.146, p = 0.064 > 0.05 for position 2). The enhanced dynamics observed with DWS is positively correlated with the functional increase of blood volume in the visual cortex, while the heartbeat rate is not affected by stimulation. Our results indicate that the DWS signal from the visual cortex is governed by the regional cerebral blood flow velocity.

  4. 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

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

    PubMed Central

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

    2015-01-01

    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

  6. 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

  7. 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…

  8. OCCIPITAL SOURCES OF RESTING STATE ALPHA RHYTHMS ARE RELATED TO LOCAL GRAY MATTER DENSITY IN SUBJECTS WITH AMNESIC MILD COGNITIVE IMPAIRMENT AND ALZHEIMER’S DISEASE

    PubMed Central

    Claudio, Babiloni; Claudio, Del Percio; Marina, Boccardi; Roberta, Lizio; Susanna, Lopez; Filippo, Carducci; Nicola, Marzano; Andrea, Soricelli; Raffaele, Ferri; Ivano, Triggiani Antonio; Annapaola, Prestia; Serenella, Salinari; Rasser Paul, E; Erol, Basar; Francesco, Famà; Flavio, Nobili; Görsev, Yener; Durusu, Emek-Savaş Derya; Gesualdo, Loreto; Ciro, Mundi; Thompson Paul, M; Rossini Paolo, M.; Frisoni Giovanni, B

    2014-01-01

    Occipital sources of resting state electroencephalographic (EEG) alpha rhythms are abnormal, at the group level, in patients with amnesic mild cognitive impairment (MCI) and Alzheimer’s disease (AD). Here we evaluated the hypothesis that amplitude of these occipital sources is related to neurodegeneration in occipital lobe as measured by magnetic resonance imaging (MRI). Resting-state eyes-closed EEG rhythms were recorded in 45 healthy elderly (Nold), 100 MCI, and 90 AD subjects. Neurodegeneration of occipital lobe was indexed by weighted averages of gray matter density (GMD), estimated from structural MRIs. EEG rhythms of interest were alpha 1 (8–10.5 Hz) and alpha 2 (10.5–13 Hz). EEG cortical sources were estimated by low resolution brain electromagnetic tomography (LORETA). Results showed a positive correlation between occipital GMD and amplitude of occipital alpha 1 sources in Nold, MCI and AD subjects as a whole group (r=0.3, p=0.000004, N=235). Furthermore, there was a positive correlation between amplitude of occipital alpha 1 sources and cognitive status as revealed by Mini Mental State Evaluation (MMSE) score across all subjects (r=0.38, p=0.000001, N=235). Finally, amplitude of occipital alpha 1 sources allowed a moderate classification of individual Nold and AD subjects (sensitivity: 87.8%; specificity: 66.7%; area under the Receiver Operating Characteristic (ROC) curve: 0.81). These results suggest that the amplitude of occipital sources of resting state alpha rhythms is related to AD neurodegeneration in occipital lobe along pathological aging. PMID:25442118

  9. Occipital sources of resting-state alpha rhythms are related to local gray matter density in subjects with amnesic mild cognitive impairment and Alzheimer's disease.

    PubMed

    Babiloni, Claudio; Del Percio, Claudio; Boccardi, Marina; Lizio, Roberta; Lopez, Susanna; Carducci, Filippo; Marzano, Nicola; Soricelli, Andrea; Ferri, Raffaele; Triggiani, Antonio Ivano; Prestia, Annapaola; Salinari, Serenella; Rasser, Paul E; Basar, Erol; Fam, Francesco; Nobili, Flavio; Yener, Grsev; Emek-Sava?, Derya Durusu; Gesualdo, Loreto; Mundi, Ciro; Thompson, Paul M; Rossini, Paolo M; Frisoni, Giovanni B

    2015-02-01

    Occipital sources of resting-state electroencephalographic (EEG) alpha rhythms are abnormal, at the group level, in patients with amnesic mild cognitive impairment (MCI) and Alzheimer's disease (AD). Here, we evaluated the hypothesis that amplitude of these occipital sources is related to neurodegeneration in occipital lobe as measured by magnetic resonance imaging. Resting-state eyes-closed EEG rhythms were recorded in 45 healthy elderly (Nold), 100 MCI, and 90 AD subjects. Neurodegeneration of occipital lobe was indexed by weighted averages of gray matter density, estimated from structural MRIs. EEG rhythms of interest were alpha 1 (8-10.5 Hz) and alpha 2 (10.5-13 Hz). EEG cortical sources were estimated by low-resolution brain electromagnetic tomography. Results showed a positive correlation between occipital gray matter density and amplitude of occipital alpha 1 sources in Nold, MCI, and AD subjects as a whole group (r = 0.3, p = 0.000004, N = 235). Furthermore, there was a positive correlation between the amplitude of occipital alpha 1 sources and cognitive status as revealed by Mini Mental State Examination score across all subjects (r = 0.38, p = 0.000001, N = 235). Finally, amplitude of occipital alpha 1 sources allowed a moderate classification of individual Nold and AD subjects (sensitivity: 87.8%; specificity: 66.7%; area under the receiver operating characteristic curve: 0.81). These results suggest that the amplitude of occipital sources of resting-state alpha rhythms is related to AD neurodegeneration in occipital lobe along pathologic aging. PMID:25442118

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

    PubMed Central

    Brewer, Alyssa A.; Barton, Brian

    2012-01-01

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

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

    PubMed

    Brewer, Alyssa A; Barton, Brian

    2014-01-01

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

  12. Frontal and occipital-parietal alpha oscillations distinguish between stimulus conflict and response conflict

    PubMed Central

    Tang, Dandan; Hu, Li; Lei, Yi; Li, Hong; Chen, Antao

    2015-01-01

    Conflicts between target and distraction can occur at the level of both stimulus and response processing. However, the neural oscillations underlying occurrence of the interference in different levels have not been understood well. Here, we reveal such a neural oscillation modulation by combining a 4:2 mapping design (two targets are mapped into one response key) with a practice paradigm (pretest, practice, and posttest) when healthy human participants were performing a novel color-word flanker task. Response time (RT) results revealed constant stimulus conflict (SC, stimulus incongruent minus congruent, SI-CO) but increased response conflict (RC, response incongruent minus stimulus incongruent, RI-SI) with practice. Event-related potential (ERP) results demonstrated stable P3 amplitude differences for the SI-CO in the centro-parietal region across practice, which may reflect maintenance of the stimulus processing; and significantly larger P3 amplitudes in the same region for the RI relative to SI trial type in posttest, which may reflect inhibition of the distraction response. Further, neural oscillatory results showed that with practice, the lower alpha band in the frontal region and the upper alpha band in the occipital-parietal region distinguished between stimulus- and response-conflicts, respectively, suggesting that practice reduces the alertness (sensitiveness) of the brain to conflict occurrence, and enhances stimulus-response associations. PMID:26300758

  13. Effects of disulfiram treatment in patients with Menkes disease and occipital horn syndrome.

    PubMed

    Ogawa, Eishin; Kodama, Hiroko

    2012-06-01

    The clinical and biochemical effects of disulfiram were evaluated in three boys with the disorders characterized by copper deficiency due to the defect of ATP7A. Two suffered from Menkes disease (MD) and one from occipital horn syndrome. Disulfiram was orally given, in addition to a parenteral administration of copper-histidine in the case of MD patients. Serum levels of copper and ceruloplasmin slightly increased in one MD patient, and he showed favorable emotional expression and behavior more often than before according to his caretakers. However, no obvious changes were observed in the other two patients. Serum ratios of noradrenaline to dopamine, and adrenaline to dopamine, which are thought to be the indicators of dopamine β-hydroxylase activity, one of the copper requiring enzymes, were unaltered after disulfiram treatment. No adverse effects were recognized during the treatment period in all patients. Although the major improvement was not observed clinically or biochemically by disulfiram treatment so far, the trial will be continued to see the possible effects in these disorders with copper transport defect. PMID:22575542

  14. The unilateral occipital transtentorial approach for pineal region meningiomas: a report of 15 cases.

    PubMed

    Qiu, Bo; Wang, Yong; Ou, Shaowu; Guo, Zongze; Wang, Yunjie

    2014-10-01

    In the current study, we reviewed and re-evaluated the experiences of microsurgical management for pineal region meningiomas via the unilateral occipital transtentorial approach (Poppen's approach). Clinical data were obtained on 15 meningiomas of the pineal region, which underwent microsurgery via unilateral Poppen's approach from March 2009 to June 2012. These patients were hospitalized in our department; their data were collected and analyzed retrospectively. The tumors were removed via the right Poppen's approach in 12 cases and left Poppen's approach in 3 cases, and intraoperative external ventricular drainage was performed for hydrocephalus in 3 cases. As a result, gross total resection was achieved in 11 cases, near total resection in 3 cases and subtotal resection in 1 case. All resected tumors were pathologically confirmed. The postoperative complications included two cases of homonymous hemianopia, and deteriorated Parinaud syndrome and diplopia in one case. Ten cases were followed up (range 1-4 years) and no death occurred. On the basis of the existing literature and our experiences, the unilateral Poppen's approach is appropriate for most meningiomas of the pineal region that are small or intermediate in size. However, gross total resection might be difficult via the unilateral Poppen's approach for large-sized meningiomas with much contralateral infratentorial extension due to limited exposure. For these cases, combined supra-infratentorial or bilateral Poppen's approaches are recommended. Preoperative or intraoperative external ventricular drainage can increase tumor exposure and improve microsurgical effects. PMID:24397496

  15. Preventive Effect of Greater Occipital Nerve Block on Severity and Frequency of Migraine Headache

    PubMed Central

    Kashipazha, Davood; Nakhostin-Mortazavi, Ali; Mohammadianinejad, Seyyed Ehsan; Bahadoram, Mohammad; Zandifar, Sepideh; Tarahomi, Shahram

    2014-01-01

    Background: Despite a favorable clinical experience, little evidence exists for the efficacy of greater occipital nerve block (GONB) in migraine treatment. Considering such a premise, we wished to evaluate the therapeutic efficacy of GONB in patients affected by migraine headaches. Methods: A randomized double-blinded controlled trial was conducted on 48 patients suffering from migraine headaches. A syringe containing 1.0 mL of lidocaine 2%, 0.5 mL of either saline (control group, N = 24) or triamcinolone 0.5 mL (intervention group, N = 24) was prepared for each patient. Patients were assessed prior to the injection, and also 2 weeks, 1 month, and 2 months thereafter for severity and frequency of pain, times to use analgesics and any appeared side effects. Results: No significant differences were revealed in pain severity, pain frequency, and analgesics use between the two groups at the four study time points including at baseline, and 2, 4, and 8 weeks after the intervention. However, in both groups, the indices of pain severity, pain frequency, and analgesics use were significantly reduced at the three time points after the intervention compared with before the intervention. Conclusion: GONB with triamcinolone in combination with lidocaine or normal saline with lidocaine results in reducing pain severity and frequency as well as use of analgesics up to two months after the intervention, however any difference attributed to the drug regimens by assessing of the trend of pain characteristics changes. PMID:25363127

  16. Social perception in schizophrenia: evidence of temporo-occipital and prefrontal dysfunction.

    PubMed

    Bjorkquist, Olivia A; Herbener, Ellen S

    2013-06-30

    Individuals with schizophrenia evidence deficits in social functioning such as difficulties in communication, maintaining employment, and functioning as a member of the community. Impairment in such functions has been linked with higher order social cognitive deficits, which, in turn, have been associated with abnormal brain function. However, it is unclear whether brain abnormalities are found specifically for higher order social cognitive functioning, or whether "lower order" social processing, such as perceiving social stimuli, might demonstrate abnormalities at the neural level. The current study used functional magnetic resonance imaging to explore the neural correlates of social perception in schizophrenia. Individuals with schizophrenia (n=14) and healthy comparison participants (n=14) viewed social (i.e., faces, people) and nonsocial (i.e., scenes, objects) images that varied in affective content (emotional, neutral). Schizophrenia patients showed decreased brain activation, compared to controls, in occipital and temporal regions associated with early visual processing, as well as increased cingulate activity, in response to emotional social relative to nonsocial images. Results indicate aberrant neural response during early stages of visual processing of social information, which may contribute to higher order social cognitive deficits characteristic of this population. PMID:23642469

  17. Tonic inhibition and ponto-geniculo-occipital-related activities shape abducens motoneuron discharge during REM sleep

    PubMed Central

    Escudero, Miguel; Márquez-Ruiz, Javier

    2008-01-01

    Eye movements, ponto-geniculo-occipital (PGO) waves, muscular atonia and desynchronized cortical activity are the main characteristics of rapid eye movement (REM) sleep. Although eye movements designate this phase, little is known about the activity of the oculomotor system during REM sleep. In this work, we recorded binocular eye movements by the scleral search-coil technique and the activity of identified abducens (ABD) motoneurons along the sleep–wake cycle in behaving cats. The activity of ABD motoneurons during REM sleep was characterized by a tonic decrease of their mean firing rate throughout this period, and short bursts and pauses coinciding with the occurrence of PGO waves. We demonstrate that the decrease in the mean firing discharge was due to an active inhibition of ABD motoneurons, and that the occurrence of primary and secondary PGO waves induced a pattern of simultaneous but opposed phasic activation and inhibition on each ABD nucleus. With regard to eye movements, during REM sleep ABD motoneurons failed to codify eye position as during alertness, but continued to codify eye velocity. The pattern of tonic inhibition and the phasic activations and inhibitions shown by ABD motoneurons coincide with those reported in other non-oculomotor motoneurons, indicating that the oculomotor system – contrary to what has been accepted until now – is not different from other motor systems during REM sleep, and that all motor systems are receiving similar command signals during this period. PMID:18499728

  18. 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

  19. 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

  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. Atypical Balance between Occipital and Fronto-Parietal Activation for Visual Shape Extraction in Dyslexia

    PubMed Central

    Zhang, Ying; Whitfield-Gabrieli, Susan; Christodoulou, Joanna A.; Gabrieli, John D. E.

    2013-01-01

    Reading requires the extraction of letter shapes from a complex background of text, and an impairment in visual shape extraction would cause difficulty in reading. To investigate the neural mechanisms of visual shape extraction in dyslexia, we used functional magnetic resonance imaging (fMRI) to examine brain activation while adults with or without dyslexia responded to the change of an arrow’s direction in a complex, relative to a simple, visual background. In comparison to adults with typical reading ability, adults with dyslexia exhibited opposite patterns of atypical activation: decreased activation in occipital visual areas associated with visual perception, and increased activation in frontal and parietal regions associated with visual attention. These findings indicate that dyslexia involves atypical brain organization for fundamental processes of visual shape extraction even when reading is not involved. Overengagement in higher-order association cortices, required to compensate for underengagment in lower-order visual cortices, may result in competition for top-down attentional resources helpful for fluent reading. PMID:23825653

  2. Retrosplenial cortex connectivity in schizophrenia.

    PubMed

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

    2009-10-30

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

  3. Progressive cortical visual failure associated with occipital calcification and coeliac disease with relative preservation of the dorsal 'action' pathway.

    PubMed

    Plant, Gordon T; James-Galton, Merle; Wilkinson, David

    2015-10-01

    We describe the first reported case of a patient with coeliac disease and cerebral occipital calcification who shows a progressive and seemingly selective failure to recognise visual stimuli. This decline was tracked over a study period of 22 years and occurred in the absence of primary sensory or widespread intellectual impairment. Subsequent tests revealed that although the patient was unable to use shape and contour information to visually identify objects, she was nevertheless able to use this information to reach, grasp and manipulate objects under central, immediate vision. This preservation of visuo-motor control was echoed in her day-to-day ability to navigate and live at home independently. We conclude that occipital calcification following coeliac disease can lead to prominent higher visual failure that, under prescribed viewing conditions, is consistent with separable mechanisms for visual perception and action control. PMID:26218620

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

    PubMed

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

    2014-11-01

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

  5. 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

  6. MRI of the tectorial and posterior atlanto-occipital membranes in the late stage of whiplash injury.

    PubMed

    Krakenes, J; Kaale, B R; Moen, G; Nordli, H; Gilhus, N E; Rorvik, J

    2003-09-01

    Our aim was to characterise and classify permanent structural changes in the tectorial and posterior atlanto-occipital membranes several years after a whiplash injury, and to evaluate the reliability of our classification. We obtained sagittal proton density-weighted images of the craniovertebral junction of 92 whiplash-injured and 30 uninjured individuals. Structural abnormalities in the two membranes were classified as grades 1-3 independently by three radiologists blinded for clinical information. Grading criteria were based on reduced tectorial membrane thickness, and elongation or rupture of the posterior atlanto-occipital membrane/dura mater complex. The same images were reassessed 4 months later. Image quality was graded good in 104 cases, slightly reduced in 13 and unsatisfactory in five. Of 117 tectorial membranes 31 (26.5%) showed grade 2 or 3 lesions, in the uninjured group none were grade 3 and only three were grade 2. Pair-wise interobserver agreement (weighted kappa) was moderate (0.47-0.50), while the intraobserver agreement was moderate to good (0.51-0.70). Of 117 posterior atlanto-occipital membranes 20 (17.1%) had grade 2 or 3 lesions; there was no grade 3 and only one grade 2 lesion in the uninjured group. Inter- and intraobserver agreement was good (0.61-0.74 and 0.65-0.86, respectively). Reduced image quality was the main reason for disagreement, but partial thinning and lateral tapering, as normal tectorial membrane variations, created difficulties in some cases. This study strongly indicates that whiplash trauma can damage the tectorial and posterior atlanto-occipital membranes; this can be shown on high-resolution MRI. Better knowledge of normal anatomical variations and improved image quality should increase the reliability of lesion classification. PMID:12904927

  7. 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

  8. Visual agnosia with bilateral temporo-occipital brain lesions in a child with autistic disorder: a case study.

    PubMed

    Mottron, L; Mineau, S; Décarie, J C; Jambaqué, I; Labrecque, R; Pépin, J P; Aroichane, M

    1997-10-01

    A 2-year-old boy meeting the criteria for autistic disorder was diagnosed 2 years later with a visual agnosia characterised by a combination of certain aspects of associative and apperceptive agnosia. MRI then revealed a severe encephalomalacia of the right temporal lobe and bilateral temporo-occipital areas. This association is discussed in terms of a clinical and aetiological relation between autistic disorder and visual agnosia. PMID:9352734

  9. Case report --surgical stabilization of a craniocervical junction abnormality with atlanto-occipital overlapping in a dog.

    PubMed

    Dewey, Curtis W; Cerda-Gonzalez, Sofia; Scrivani, Peter V

    2009-10-01

    A 3-year-old male neutered Pomeranian presented with severe, poorly localizable pain that was unresponsive to a combination of oral medications (gabapentin, tramadol, prednisone, and methocarbamol) and a fentanyl patch. A Chiari-like malformation with associated syringomyelia was evident on magnetic resonance imaging (MRI). In addition, overlapping of the dorsal arch of C1 and the dorsal aspect of the foramen magnum was suspected from the MRI scans and verified via computed tomography, suggesting a condition similar to basilar invagination/impression in people. At surgery, a combination of foramen magnum decompression with cranioplasty and stabilization of the atlanto-occipital junction was performed. The atlanto-occipital junction was stabilized using an adaptation of a procedure used in people for basilar invagination/impression. Over the next several months, the dog's clinical signs improved dramatically, allowing substantial reduction of oral pain medications. This is the first report of surgical stabilization for atlanto-occipital overlapping in a dog. PMID:23710494

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

    PubMed

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

    2015-01-01

    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

  12. 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.

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

    PubMed

    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

  14. Creating Concepts from Converging Features in Human Cortex.

    PubMed

    Coutanche, Marc N; Thompson-Schill, Sharon L

    2015-09-01

    To make sense of the world around us, our brain must remember the overlapping features of millions of objects. Crucially, it must also represent each object's unique feature-convergence. Some theories propose that an integration area (or "convergence zone") binds together separate features. We report an investigation of our knowledge of objects' features and identity, and the link between them. We used functional magnetic resonance imaging to record neural activity, as humans attempted to detect a cued fruit or vegetable in visual noise. Crucially, we analyzed brain activity before a fruit or vegetable was present, allowing us to interrogate top-down activity. We found that pattern-classification algorithms could be used to decode the detection target's identity in the left anterior temporal lobe (ATL), its shape in lateral occipital cortex, and its color in right V4. A novel decoding-dependency analysis revealed that identity information in left ATL was specifically predicted by the temporal convergence of shape and color codes in early visual regions. People with stronger feature-and-identity dependencies had more similar top-down and bottom-up activity patterns. These results fulfill three key requirements for a neural convergence zone: a convergence result (object identity), ingredients (color and shape), and the link between them. PMID:24692512

  15. Decoding face categories in diagnostic subregions of primary visual cortex

    PubMed Central

    Petro, Lucy S; Smith, Fraser W; Schyns, Philippe G; Muckli, Lars

    2013-01-01

    Higher visual areas in the occipitotemporal cortex contain discrete regions for face processing, but it remains unclear if V1 is modulated by top-down influences during face discrimination, and if this is widespread throughout V1 or localized to retinotopic regions processing task-relevant facial features. Employing functional magnetic resonance imaging (fMRI), we mapped the cortical representation of two feature locations that modulate higher visual areas during categorical judgements – the eyes and mouth. Subjects were presented with happy and fearful faces, and we measured the fMRI signal of V1 regions processing the eyes and mouth whilst subjects engaged in gender and expression categorization tasks. In a univariate analysis, we used a region-of-interest-based general linear model approach to reveal changes in activation within these regions as a function of task. We then trained a linear pattern classifier to classify facial expression or gender on the basis of V1 data from ‘eye’ and ‘mouth’ regions, and from the remaining non-diagnostic V1 region. Using multivariate techniques, we show that V1 activity discriminates face categories both in local ‘diagnostic’ and widespread ‘non-diagnostic’ cortical subregions. This indicates that V1 might receive the processed outcome of complex facial feature analysis from other cortical (i.e. fusiform face area, occipital face area) or subcortical areas (amygdala). PMID:23373719

  16. 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

  17. The chronometry of visual perception: review of occipital TMS masking studies.

    PubMed

    de Graaf, Tom A; Koivisto, Mika; Jacobs, Christianne; Sack, Alexander T

    2014-09-01

    Transcranial magnetic stimulation (TMS) continues to deliver on its promise as a research tool. In this review article we focus on the application of TMS to early visual cortex (V1, V2, V3) in studies of visual perception and visual awareness. Depending on the asynchrony between visual stimulus onset and TMS pulse (SOA), TMS can suppress visual perception, allowing one to track the time course of functional relevance (chronometry) of early visual cortex for vision. This procedure has revealed multiple masking effects ('dips'), some consistently (∼+100ms SOA) but others less so (∼-50ms, ∼-20ms, ∼+30ms, ∼+200ms SOA). We review the state of TMS masking research, focusing on the evidence for these multiple dips, the relevance of several experimental parameters to the obtained 'masking curve', and the use of multiple measures of visual processing (subjective measures of awareness, objective discrimination tasks, priming effects). Lastly, we consider possible future directions for this field. We conclude that while TMS masking has yielded many fundamental insights into the chronometry of visual perception already, much remains unknown. Not only are there several temporal windows when TMS pulses can induce visual suppression, even the well-established 'classical' masking effect (∼+100ms) may reflect more than one functional visual process. PMID:25010557

  18. Perceptual specificity in visual object priming: functional magnetic resonance imaging evidence for a laterality difference in fusiform cortex.

    PubMed

    Koutstaal, W; Wagner, A D; Rotte, M; Maril, A; Buckner, R L; Schacter, D L

    2001-01-01

    Seeing an object on one occasion may facilitate or prime processing of the same object if it is later again encountered. Such priming may also be found -- but at a reduced level -- for different but perceptually similar objects that are alternative exemplars or 'tokens' of the initially presented object. We explored the neural correlates of this perceptual specificity using event-related functional magnetic resonance imaging (fMRI) procedures, contrasting neural activity when participants made object classification decisions (size judgments) regarding previously presented objects (repeated same), alternative exemplars of previously presented objects (repeated different), or entirely new objects (novel). Many frontal regions (including bilateral frontal operculum, bilateral posterior inferior frontal/precentral, left anterior inferior frontal, and superior frontal cortices) and multiple late visual and posterior regions (including middle occipital, fusiform, fusiform-parahippocampal, precuneus, and posterior cingulate, all bilaterally), demonstrated reduced neural activity for repeated compared to novel objects. Greater repetition-induced reductions were observed for same than for different exemplars in several of these regions (bilateral posterior inferior frontal, right precuneus, bilateral middle occipital, bilateral fusiform, bilateral parahippocampal and bilateral superior parietal). Additionally, right fusiform (occipitotemporal) cortex showed significantly less priming for different versus same exemplars than did left fusiform. These findings converge with behavioral evidence from divided visual field studies and with neuropsychological evidence underscoring the key role of right occipitotemporal cortex in processing specific visual form information; possible differences in the representational-functional role of left fusiform are discussed. PMID:11163375

  19. Altered SPECT 123I-iomazenil Binding in the Cingulate Cortex of Children with Anorexia Nervosa

    PubMed Central

    Nagamitsu, Shinichiro; Sakurai, Rieko; Matsuoka, Michiko; Chiba, Hiromi; Ozono, Shuichi; Tanigawa, Hitoshi; Yamashita, Yushiro; Kaida, Hayato; Ishibashi, Masatoshi; Kakuma, Tatsuki; Croarkin, Paul E.; Matsuishi, Toyojiro

    2016-01-01

    Several lines of evidence suggest that anxiety plays a key role in the development and maintenance of anorexia nervosa (AN) in children. The purpose of this study was to examine cortical GABA(A)-benzodiazepine receptor binding before and after treatment in children beginning intensive AN treatment. Brain single-photon emission computed tomography (SPECT) measurements using 123I-iomazenil, which binds to GABA(A)-benzodiazepine receptors, was performed in 26 participants with AN who were enrolled in a multimodal treatment program. Sixteen of the 26 participants underwent a repeat SPECT scan immediately before discharge at conclusion of the intensive treatment program. Eating behavior and mood disturbances were assessed using Eating Attitudes Test with 26 items (EAT-26) and the short form of the Profile of Mood States (POMS). Clinical outcome scores were evaluated after a 1-year period. We examined association between relative iomazenil-binding activity in cortical regions of interest and psychometric profiles and determined which psychometric profiles show interaction effects with brain regions. Further, we determined if binding activity could predict clinical outcome and treatment changes. Higher EAT-26 scores were significantly associated with lower iomazenil-binding activity in the anterior and posterior cingulate cortex. Higher POMS subscale scores were significantly associated with lower iomazenil-binding activity in the left frontal, parietal cortex, and posterior cingulate cortex (PCC). “Depression–Dejection” and “Confusion” POMS subscale scores, and total POMS score showed interaction effects with brain regions in iomazenil-binding activity. Decreased binding in the anterior cingulate cortex and left parietal cortex was associated with poor clinical outcomes. Relative binding increases throughout the PCC and occipital gyrus were observed after weight gain in children with AN. These findings suggest that cortical GABAergic receptor binding is altered in children with AN. This may be a state-related change, which could be used to monitor and guide the treatment of eating disorders. PMID:26909048

  20. Interaction between visual and motor cortex: a transcranial magnetic stimulation study.

    PubMed

    Strigaro, Gionata; Ruge, Diane; Chen, Jui-Cheng; Marshall, Louise; Desikan, Mahalekshmi; Cantello, Roberto; Rothwell, John C

    2015-05-15

    The major link between the visual and motor systems is via the dorsal stream pathways from visual to parietal and frontal areas of the cortex. Although the pathway appears to be indirect, there is evidence that visual input can reach the motor cortex at relatively short latency. To shed some light on its neural basis, we studied the visuomotor interaction using paired transcranial magnetic stimulation (TMS). Motor-evoked potentials (MEPs) were recorded from the right first dorsal interosseous in sixteen healthy volunteers. A conditioning stimulus (CS) was applied over the phosphene hotspot of the visual cortex, followed by a test stimulus over the left primary motor cortex (M1) with a random interstimulus interval (ISI) in range 12-40 ms. The effects of paired stimulation were retested during visual and auditory reaction-time tasks (RT). Finally, we measured the effects of a CS on short-interval intracortical inhibition (SICI). At rest, a CS over the occiput significantly (P < 0.001) suppressed test MEPs with an ISI in the range 18-40 ms. In the visual RT, inhibition with an ISI of 40 ms (but not 18 ms) was replaced by a time-specific facilitation (P < 0.001), whereas, in the auditory RT, the CS no longer had any effect on MEPs. Finally, an occipital CS facilitated SICI with an ISI of 40 ms (P < 0.01). We conclude that it is possible to study separate functional connections from visual to motor cortices using paired-TMS with an ISI in the range 18-40 ms. The connections are inhibitory at rest and possibly mediated by inhibitory interneurones in the motor cortex. The effect with an ISI of 40 ms reverses into facilitation during a visuomotor RT but not an audiomotor RT. This suggests that it plays a role in visuomotor integration. PMID:25762215

  1. Altered SPECT (123)I-iomazenil Binding in the Cingulate Cortex of Children with Anorexia Nervosa.

    PubMed

    Nagamitsu, Shinichiro; Sakurai, Rieko; Matsuoka, Michiko; Chiba, Hiromi; Ozono, Shuichi; Tanigawa, Hitoshi; Yamashita, Yushiro; Kaida, Hayato; Ishibashi, Masatoshi; Kakuma, Tatsuki; Croarkin, Paul E; Matsuishi, Toyojiro

    2016-01-01

    Several lines of evidence suggest that anxiety plays a key role in the development and maintenance of anorexia nervosa (AN) in children. The purpose of this study was to examine cortical GABA(A)-benzodiazepine receptor binding before and after treatment in children beginning intensive AN treatment. Brain single-photon emission computed tomography (SPECT) measurements using (123)I-iomazenil, which binds to GABA(A)-benzodiazepine receptors, was performed in 26 participants with AN who were enrolled in a multimodal treatment program. Sixteen of the 26 participants underwent a repeat SPECT scan immediately before discharge at conclusion of the intensive treatment program. Eating behavior and mood disturbances were assessed using Eating Attitudes Test with 26 items (EAT-26) and the short form of the Profile of Mood States (POMS). Clinical outcome scores were evaluated after a 1-year period. We examined association between relative iomazenil-binding activity in cortical regions of interest and psychometric profiles and determined which psychometric profiles show interaction effects with brain regions. Further, we determined if binding activity could predict clinical outcome and treatment changes. Higher EAT-26 scores were significantly associated with lower iomazenil-binding activity in the anterior and posterior cingulate cortex. Higher POMS subscale scores were significantly associated with lower iomazenil-binding activity in the left frontal, parietal cortex, and posterior cingulate cortex (PCC). "Depression-Dejection" and "Confusion" POMS subscale scores, and total POMS score showed interaction effects with brain regions in iomazenil-binding activity. Decreased binding in the anterior cingulate cortex and left parietal cortex was associated with poor clinical outcomes. Relative binding increases throughout the PCC and occipital gyrus were observed after weight gain in children with AN. These findings suggest that cortical GABAergic receptor binding is altered in children with AN. This may be a state-related change, which could be used to monitor and guide the treatment of eating disorders. PMID:26909048

  2. NMDA Receptor Antagonist Ketamine Distorts Object Recognition by Reducing Feedback to Early Visual Cortex.

    PubMed

    van Loon, Anouk M; Fahrenfort, Johannes J; van der Velde, Bauke; Lirk, Philipp B; Vulink, Nienke C C; Hollmann, Markus W; Steven Scholte, H; Lamme, Victor A F

    2016-05-01

    It is a well-established fact that top-down processes influence neural representations in lower-level visual areas. Electrophysiological recordings in monkeys as well as theoretical models suggest that these top-down processes depend on NMDA receptor functioning. However, this underlying neural mechanism has not been tested in humans. We used fMRI multivoxel pattern analysis to compare the neural representations of ambiguous Mooney images before and after they were recognized with their unambiguous grayscale version. Additionally, we administered ketamine, an NMDA receptor antagonist, to interfere with this process. Our results demonstrate that after recognition, the pattern of brain activation elicited by a Mooney image is more similar to that of its easily recognizable grayscale version than to the pattern evoked by the identical Mooney image before recognition. Moreover, recognition of Mooney images decreased mean response; however, neural representations of separate images became more dissimilar. So from the neural perspective, unrecognizable Mooney images all "look the same", whereas recognized Mooneys look different. We observed these effects in posterior fusiform part of lateral occipital cortex and in early visual cortex. Ketamine distorted these effects of recognition, but in early visual cortex only. This suggests that top-down processes from higher- to lower-level visual areas might operate via an NMDA pathway. PMID:25662715

  3. Context Memory Decline in Middle Aged Adults is Related to Changes in Prefrontal Cortex Function.

    PubMed

    Kwon, Diana; Maillet, David; Pasvanis, Stamatoula; Ankudowich, Elizabeth; Grady, Cheryl L; Rajah, M Natasha

    2016-06-01

    The ability to encode and retrieve spatial and temporal contextual details of episodic memories (context memory) begins to decline at midlife. In the current study, event-related fMRI was used to investigate the neural correlates of context memory decline in healthy middle aged adults (MA) compared with young adults (YA). Participants were scanned while performing easy and hard versions of spatial and temporal context memory tasks. Scans were obtained at encoding and retrieval. Significant reductions in context memory retrieval accuracy were observed in MA, compared with YA. The fMRI results revealed that overall, both groups exhibited similar patterns of brain activity in parahippocampal cortex, ventral occipito-temporal regions and prefrontal cortex (PFC) during encoding. In contrast, at retrieval, there were group differences in ventral occipito-temporal and PFC activity, due to these regions being more activated in MA, compared with YA. Furthermore, only in YA, increased encoding activity in ventrolateral PFC, and increased retrieval activity in occipital cortex, predicted increased retrieval accuracy. In MA, increased retrieval activity in anterior PFC predicted increased retrieval accuracy. These results suggest that there are changes in PFC contributions to context memory at midlife. PMID:25882039

  4. 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

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

    PubMed

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

    2013-02-01

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

  6. Cervico-occipital Posture in Women With Migraine: A Case-Control Study.

    PubMed

    Ferracini, Gabriela Natália; Dach, Fabíola; Chaves, Thais Cristina; Pinheiro, Carina Ferreira; Bevilaqua-Grossi, Débora; Fernández-de-Las-Peñas, César; Speciali, José Geraldo

    2016-04-01

    Study Design Case-control study. Background Previous studies have assessed forward head posture in patients with migraine using photographs. To date, no study has compared postural differences using both radiographs and photographs. Objective To determine the differences in head extension posture between women with migraine and healthy women assessed with radiographic and photographic measures. Methods Thirty-three women (mean ± SD age, 32 ± 11.3 years) with migraine and 33 matched controls (age, 33 ± 12.6 years) participated. Radiographs were used to measure the high cervical angle (HCA), the angle between the most inferior line from the occipital surface to the posterior portion of C1 and the posterior surface of the odontoid process of C2, and the vertical distance between C0 and C1 (C0-C1). Photographs and commercially available software were used to assess the craniovertebral angle (CVA). Results None of the outcomes differed significantly between women with migraine and control participants. Outcomes for women with migraine were HCA, 66.1° (95% confidence interval [CI]: 64.2°, 68.1°); CVA, 46.1° (95% CI: 45.0°, 47.1°); and C0-C1, 8.5 mm (95% CI: 7.7, 9.2). Outcomes for the control group were HCA, 67.9° (95% CI: 66.5°, 69.3°); CVA, 44.5° (95% CI: 43.2°, 45.7°); and C0-C1, 8.7 mm (95% CI: 7.9, 9.4). Relationships between the frequency (r = -0.42, P = .01, R (2) = 10%) of migraine and the HCA were found. Conclusion This study demonstrated that women with migraine did not exhibit forward head posture compared to women with no history of headache in either radiographic or photographic postural analysis. However, there was a weak association of the frequency of migraine attacks with a variation in the HCA as assessed by radiographs. Level of Evidence Differential diagnosis/symptom prevalence, level 4. J Orthop Sports Phys Ther 2016;46(4):251-257. Epub 8 Mar 2016. doi:10.2519/jospt.2016.6166. PMID:26954270

  7. Feasibility of C2 Vertebra Screws Placement in Patient With Occipitalization of Atlas: A Tomographic Study.

    PubMed

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

    2015-09-01

    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 < 0.05. A total of 73 patients (29 males and 44 females) were eligible to be included in the OA group. In most of the measurements the pathological cohort had significantly smaller values compared to the control group (P < 0.05). In the OA group, only 45% of the pedicles and 88% of the lamina had thicknesses bigger than 3.5 mm. Both groups had all pedicle and lamina lengths bigger than 12 mm. Regarding the length of the lateral mass, no value was bigger than 12 mm in the OA group, whereas 40% of the values in the control group were bigger than 12 mm. The average pedicle and laminar angles were 37° and 49° in the patients with OA, respectively. The variable anatomy in patients with OA needs to be taken into account when performing spinal stabilization as the C2 bony architectures are significantly smaller than normal. Anatomically, translaminar screw is a more viable option in comparison with pedicle screw for C2 fixation in OA. Nevertheless, the suitability should be fully assessed prior to surgery. PMID:26376390

  8. 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?

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

    PubMed Central

    Sprague, Thomas C.; Serences, John T.

    2014-01-01

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

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

    PubMed

    Sprague, Thomas C; Serences, John T

    2013-12-01

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

  11. Canonical computations of cerebral cortex.

    PubMed

    Miller, Kenneth D

    2016-04-01

    The idea that there is a fundamental cortical circuit that performs canonical computations remains compelling though far from proven. Here we review evidence for two canonical operations within sensory cortical areas: a feedforward computation of selectivity; and a recurrent computation of gain in which, given sufficiently strong external input, perhaps from multiple sources, intracortical input largely, but not completely, cancels this external input. This operation leads to many characteristic cortical nonlinearities in integrating multiple stimuli. The cortical computation must combine such local processing with hierarchical processing across areas. We point to important changes in moving from sensory cortex to motor and frontal cortex and the possibility of substantial differences between cortex in rodents vs. species with columnar organization of selectivity. PMID:26868041

  12. Dose-Dependent Changes in Auditory Sensory Gating in the Prefrontal Cortex of the Cynomolgus Monkey.

    PubMed

    Huang, Hui; Ya, Jinrong; Wu, Zhe; Wen, Chunmei; Zheng, Suyue; Tian, Chaoyang; Ren, Hui; Carlson, Synnöve; Yu, Hualin; Chen, Feng; Wang, Jianhong

    2016-01-01

    BACKGROUND Sensory gating, often described as the ability to filter out irrelevant information that is repeated in close temporal proximity, is essential for the selection, processing, and storage of more salient information. This study aimed to test the effect of sensory gating under anesthesia in the prefrontal cortex (PFC) of monkeys following injection of bromocriptine, haloperidol, and phencyclidine (PCP). MATERIAL AND METHODS We used an auditory evoked potential that can be elicited by sound to examine sensory gating during treatment with haloperidol, bromocriptine, and PCP in the PFC in the cynomolgus monkey. Scalp electrodes were located in the bilateral PFC and bilateral temporal, bilateral parietal, and occipital lobes. Administration of bromocriptine (0.313 mg/kg, 0.625 mg/kg, and 1.25 mg/kg), haloperidol (0.001 mg/kg, 0.01 mg/kg, and 0.05 mg/kg), and the N-methyl-D-aspartic acid receptor antagonist PCP (0.3 mg/kg) influenced sensory gating. RESULTS We demonstrated the following: (1) Administration of mid-dose bromocriptine disrupted sensory gating (N100) in the right temporal lobe, while neither low-dose nor high-dose bromocriptine impaired gating. (2) Low-dose haloperidol impaired gating in the right prefrontal cortex. Mid-dose haloperidol disrupted sensory gating in left occipital lobe. High-dose haloperidol had no obvious effect on sensory gating. (3) Gating was impaired by PCP in the left parietal lobe. CONCLUSIONS Our studies showed that information processing was regulated by the dopaminergic system, which might play an important role in the PFC. The dopaminergic system influenced sensory gating in a dose- and region-dependent pattern, which might modulate the different stages that receive further processing due to novel information. PMID:27218151

  13. 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.

  14. 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

  15. Increased glutamate levels observed upon functional activation in the anterior cingulate cortex using the Stroop Task and functional spectroscopy

    PubMed Central

    Schaefer, Betsy; Densmore, Maria; Neufeld, Richard W.J.; Rajakumar, Nagalingam; Williamson, Peter C.; Théberge, Jean

    2015-01-01

    It has been shown in recent studies that it is possible to detect changes in the main excitatory neurotransmitter, glutamate, upon functional activation with visual and motor paradigms using a 7 T MRI and functional magnetic resonance spectroscopy. A cognitive task would be desirable for this technique because it could then be used to examine psychiatric disorders that have cognitive deficiencies. The aim of the work presented here was to use functional magnetic resonance spectroscopy with a 7 T MRI to show that increases in glutamate can be observed within the anterior cingulate cortex using the Stroop Task as the activation paradigm in healthy controls. Significant glutamate increases (0.24±0.09 µmol/g, P<0.025), comparable with what has been reported in the studies of the occipital cortex and motor cortex, were observed when the participants (n=7) performed the task, followed by a trend toward returning to baseline in the post-task recovery period (−0.23±0.13 µmol/g). This method would be ideal for the study of neuropsychiatric disorders that have been shown to have abnormal resting glutamate levels and cognitive deficiencies in the anterior cingulate cortex, such as schizophrenia. This exploratory study is the first to demonstrate functional magnetic resonance spectroscopy in the anterior cingulate with a cognitive task using a 7 T MRI. PMID:25536234

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

    PubMed

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

    2014-04-01

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

  17. 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

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

    PubMed Central

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

    2014-01-01

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

  19. Strokes and vision: The management of ischemic arterial disease affecting the retina and occipital lobe.

    PubMed

    Lawlor, Mitchell; Perry, Richard; Hunt, Beverley J; Plant, Gordon T

    2015-01-01

    Embolic disease of the anterior or posterior vascular territories may lead to disturbance of vision. Although death from this is uncommon, morbidity remains relatively high: Visual field loss may impair or preclude reading and driving and these are important influences on quality of life. Visual symptoms of stroke mean that patients may present to ophthalmologists with isolated visual symptoms, rather than directly to an emergency department. It is important to diagnose stroke and transient ischemic attacks accurately, as well as to manage them appropriately, as they are important harbingers of further cerebrovascular events. Ophthalmologists are therefore well placed to ensure that these patients receive appropriate acute treatment and secondary prevention. This article reviews the evidence for managing patients presenting with visual symptoms of vascular events. It reviews management of ischemic stroke in general, and compares this with management of events involving the anterior circulation by way of transient monocular visual loss or retinal artery occlusion, and posterior circulation by way of transient binocular visual loss or infarction of the visual cortex. PMID:25937273

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

    PubMed

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

    2015-07-01

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

  1. Phosphenes and transient scotomas induced by magnetic stimulation of the occipital lobe: their topographic relationship.

    PubMed

    Kammer, T

    1999-02-01

    Transcranial magnetic stimulation (TMS) of the visual cortex is known to induce phosphenes and is able to suppress visual perception. To address the topographic relationship of phosphenes and transient scotomas, the visual field of 10 normal subjects was investigated using a perimetric approach. The central visual field (diameter: 20 degrees) was tested at 32 sites. Perceptual thresholds were determined by presenting 1 ms test spots flashed with varying intensity in random order. TMS was applied with a focal figure-of-eight coil placed over the inion. All subjects perceived phosphenes, mostly restricted to one of the lower quadrants within the visual field. In 13 out of 15 investigations, a magnetic stimulus triggered 100 ms after the visual target resulted in a relative scotoma with threshold changes of 8 dB or more. In 9 of 13 investigations, scotomas coincided spatially with sketches of phosphenes made by subjects in a separate test. Scotomas covered only a small percentage of the total visual field, which may explain the failure of previous studies to find perceptual suppression with the focal coil. The present result demonstrates that phosphenes evoked during TMS can serve as a guide for optimal visual stimulus alignment in neuropsychological experiments. PMID:10080376

  2. 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

  3. 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…

  4. Action: the role of motor cortex challenged.

    PubMed

    Grillner, Sten

    2015-06-15

    The motor cortex is often considered the main controller for movement, but a new study shows that well-trained paw movements can be performed with equal precision after lesions of the entire motor cortex; the motor cortex is, however, required for learning a new task in naïve animals. PMID:26079084

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

    PubMed

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

    2014-11-01

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

  6. The controversial existence of the human superior fronto-occipital fasciculus: Connectome-based tractographic study with microdissection validation.

    PubMed

    Meola, Antonio; Comert, Ayhan; Yeh, Fang-Cheng; Stefaneanu, Lucia; Fernandez-Miranda, Juan C

    2015-12-01

    The superior fronto-occipital fasciculus (SFOF), a long association bundle that connects frontal and occipital lobes, is well-documented in monkeys but is controversial in human brain. Its assumed role is in visual processing and spatial awareness. To date, anatomical and neuroimaging studies on human and animal brains are not in agreement about the existence, course, and terminations of SFOF. To clarify the existence of the SFOF in human brains, we applied deterministic fiber tractography to a template of 488 healthy subjects and to 80 individual subjects from the Human Connectome Project (HCP) and validated the results with white matter microdissection of post-mortem human brains. The imaging results showed that previous reconstructions of the SFOF were generated by two false continuations, namely between superior thalamic peduncle (STP) and stria terminalis (ST), and ST and posterior thalamic peduncle. The anatomical microdissection confirmed this finding. No other fiber tracts in the previously described location of the SFOF were identified. Hence, our data suggest that the SFOF does not exist in the human brain. Hum Brain Mapp 36:4964-4971, 2015. © 2015 Wiley Periodicals, Inc. PMID:26435158

  7. 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

  8. 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

  9. 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

  10. Prefrontal cortex white matter tracts in prodromal Huntington disease.

    PubMed

    Matsui, Joy T; Vaidya, Jatin G; Wassermann, Demian; Kim, Regina Eunyoung; Magnotta, Vincent A; Johnson, Hans J; Paulsen, Jane S

    2015-10-01

    Huntington disease (HD) is most widely known for its selective degeneration of striatal neurons but there is also growing evidence for white matter (WM) deterioration. The primary objective of this research was to conduct a large-scale analysis using multisite diffusion-weighted imaging (DWI) tractography data to quantify diffusivity properties along major prefrontal cortex WM tracts in prodromal HD. Fifteen international sites participating in the PREDICT-HD study collected imaging and neuropsychological data on gene-positive HD participants without a clinical diagnosis (i.e., prodromal) and gene-negative control participants. The anatomical prefrontal WM tracts of the corpus callosum (PFCC), anterior thalamic radiations (ATRs), inferior fronto-occipital fasciculi (IFO), and uncinate fasciculi (UNC) were identified using streamline tractography of DWI. Within each of these tracts, tensor scalars for fractional anisotropy, mean diffusivity, radial diffusivity, and axial diffusivity coefficients were calculated. We divided prodromal HD subjects into three CAG-age product (CAP) groups having Low, Medium, or High probabilities of onset indexed by genetic exposure. We observed significant differences in WM properties for each of the four anatomical tracts for the High CAP group in comparison to controls. Additionally, the Medium CAP group presented differences in the ATR and IFO in comparison to controls. Furthermore, WM alterations in the PFCC, ATR, and IFO showed robust associations with neuropsychological measures of executive functioning. These results suggest long-range tracts essential for cross-region information transfer show early vulnerability in HD and may explain cognitive problems often present in the prodromal stage. Hum Brain Mapp 36:3717-3732, 2015. © 2015 Wiley Periodicals, Inc. PMID:26179962

  11. Human vestibular cortex as identified with caloric stimulation in functional magnetic resonance imaging.

    PubMed

    Fasold, Oliver; von Brevern, Michael; Kuhberg, Marc; Ploner, Christoph J; Villringer, Arno; Lempert, Thomas; Wenzel, Rüdiger

    2002-11-01

    Anatomic and electrophysiological studies in monkeys have yielded a detailed map of cortex areas receiving vestibular afferents. In contrast, comparatively little is known about the cortical representation of the human vestibular system. In this study we applied caloric stimulation and fMRI to further characterize human cortical vestibular areas and to test for hemispheric dominance of vestibular information processing. For caloric vestibular stimulation we used cold nitrogen to avoid susceptibility artifacts induced by water calorics. Right and left side vestibular stimulation was repetitively performed inducing a nystagmus for at least 90 s after the end of the stimulation in all subjects. Only the first 60 s of this nystagmus period was included for statistical analysis and compared with the baseline condition. Activation maps revealed a cortical network with right hemispheric dominance, which in all subjects comprised the temporoparietal junction extending into the posterior insula and, furthermore, the anterior insula, pre- and postcentral gyrus, areas in the parietal lobe, the ventrolateral portion of the occipital lobe, and the inferior frontal gyrus extending into the inferior part of the precentral sulcus. In conclusion, caloric stimulation in fMRI reveals a widespread cortical network involved in vestibular signal processing corresponding to the findings from animal experiments and previous functional imaging studies in humans. Furthermore, this study demonstrates a strong right hemispheric dominance of vestibular cortex areas regardless of the stimulated side, consistent with the current view of a rightward asymmetrical cortical network for spatial orientation. PMID:12414278

  12. Individual attentional selection capacities are reflected in interhemispheric connectivity of the parietal cortex.

    PubMed

    Vossel, Simone; Weidner, Ralph; Moos, Katharina; Fink, Gereon R

    2016-04-01

    Modelling psychophysical data using the Theory of Visual Attention (TVA) allows for a quantification of attentional sub-processes, such as the resolution of competition amongst multiple stimuli by top-down control signals for target selection (TVA-parameter α). This fMRI study investigated the neural correlates of α by comparing activity differences and changes of effective connectivity between conditions where a target was accompanied by a distractor or by a second target. Twenty-five participants performed a partial report task inside the MRI scanner. The left angular gyrus (ANG), medial frontal, and posterior cingulate cortex showed higher activity when a target was accompanied by a distractor as opposed to a second target. The reverse contrast yielded activation of a bilateral fronto-parietal network, the anterior insula, anterior cingulate cortex, and left inferior occipital gyrus. A psychophysiological interaction analysis revealed that the connectivity between left ANG and the left and right supramarginal gyrus (SMG), left anterior insula, and right putamen was enhanced in the target-distractor condition in participants with worse attentional top-down control. Dynamic causal modelling suggested that the connection from left ANG to right SMG during distractor presence was modulated by α. Our data show that interindividual differences in attentional processing are reflected in changes of effective connectivity without significant differences in activation strength of network nodes. PMID:26827815

  13. Functional Mapping of Face-Selective Regions in the Extrastriate Visual Cortex of the Marmoset

    PubMed Central

    Hung, Chia-Chun; Yen, Cecil C.; Ciuchta, Jennifer L.; Papoti, Daniel; Bock, Nicholas A.; Leopold, David A.

    2015-01-01

    The cerebral cortex of humans and macaques has specialized regions for processing faces and other visual stimulus categories. It is unknown whether a similar functional organization exists in New World monkeys, such as the common marmoset (Callithrix jacchus), a species of growing interest as a primate model in neuroscience. To address this question, we measured selective neural responses in the brain of four awake marmosets trained to fix their gaze upon images of faces, bodies, objects, and control patterns. In two of the subjects, we measured high gamma-range field potentials from electrocorticography arrays implanted over a large portion of the occipital and inferotemporal cortex. In the other two subjects, we measured BOLD fMRI responses across the entire brain. Both techniques revealed robust, regionally specific patterns of category-selective neural responses. We report that at least six face-selective patches mark the occipitotemporal pathway of the marmoset, with the most anterior patches showing the strongest preference for faces over other stimuli. The similar appearance of these patches to previous findings in macaques and humans, including their apparent arrangement in two parallel pathways, suggests that core elements of the face processing network were present in the common anthropoid primate ancestor living ∼35 million years ago. The findings also identify the marmoset as a viable animal model system for studying specialized neural mechanisms related to high-level social visual perception in humans. PMID:25609630

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

    PubMed

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

    2014-10-20

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

  15. Lateralization of the posterior parietal cortex for internal monitoring of self- versus externally generated movements.

    PubMed

    Ogawa, Kenji; Inui, Toshio

    2007-11-01

    Internal monitoring or state estimation of movements is essential for human motor control to compensate for inherent delays and noise in sensorimotor loops. Two types of internal estimation of movements exist: self-generated movements, and externally generated movements. We used functional magnetic resonance imaging to investigate differences in brain activity for internal monitoring of self- versus externally generated movements during visual occlusion. Participants tracked a sinusoidally moving target with a mouse cursor. On some trials, vision of either target (externally generated) or cursor (self-generated) movement was transiently occluded, during which subjects continued tracking by estimating current position of either the invisible target or cursor on screen. Analysis revealed that both occlusion conditions were associated with increased activity in the presupplementary motor area and decreased activity in the right lateral occipital cortex compared to a control condition with no occlusion. Moreover, the right and left posterior parietal cortex (PPC) showed greater activation during occlusion of target and cursor movements, respectively. This study suggests lateralization of the PPC for internal monitoring of internally versus externally generated movements, fully consistent with previously reported clinical findings. PMID:17958485

  16. 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

  17. Different neural mechanisms within occipitotemporal cortex underlie repetition suppression across same and different-size faces.

    PubMed

    Ewbank, Michael P; Henson, Richard N; Rowe, James B; Stoyanova, Raliza S; Calder, Andrew J

    2013-05-01

    Repetition suppression (RS) (or functional magnetic resonance imaging adaptation) refers to the reduction in blood oxygen level-dependent signal following repeated presentation of a stimulus. RS is frequently used to investigate the role of face-selective regions in human visual cortex and is commonly thought to be a "localized" effect, reflecting fatigue of a neuronal population representing a given stimulus. In contrast, predictive coding theories characterize RS as a consequence of "top-down" changes in between-region modulation. Differentiating between these accounts is crucial for the correct interpretation of RS effects in the face-processing network. Here, dynamic causal modeling revealed that different mechanisms underlie different forms of RS to faces in occipitotemporal cortex. For both familiar and unfamiliar faces, repetition of identical face images (same size) was associated with changes in "forward" connectivity between the occipital face area (OFA) and the fusiform face area (FFA) (OFA-to-FFA). In contrast, RS across image size was characterized by altered "backward" connectivity (FFA-to-OFA). In addition, evidence was higher for models in which information projected directly into both OFA and FFA, challenging the role of OFA as the input stage of the face-processing network. These findings suggest "size-invariant" RS to faces is a consequence of interactions between regions rather than being a localized effect. PMID:22510534

  18. Orbitofrontal Cortex and the Early Processing of Visual Novelty in Healthy Aging

    PubMed Central

    Kaufman, David A. S.; Keith, Cierra M.; Perlstein, William M.

    2016-01-01

    Event-related potential (ERP) studies have previously found that scalp topographies of attention-related ERP components show frontal shifts with age, suggesting an increased need for compensatory frontal activity to assist with top-down facilitation of attention. However, the precise neural time course of top-down attentional control in aging is not clear. In this study, 20 young (mean: 22 years) and 14 older (mean: 64 years) adults completed a three-stimulus visual oddball task while high-density ERPs were acquired. Colorful, novel distracters were presented to engage early visual processing. Relative to young controls, older participants exhibited elevations in occipital early posterior positivity (EPP), approximately 100 ms after viewing colorful distracters. Neural source models for older adults implicated unique patterns of orbitofrontal cortex (OFC; BA 11) activity during early visual novelty processing (100 ms), which was positively correlated with subsequent activations in primary visual cortex (BA 17). Older adult EPP amplitudes and OFC activity were associated with performance on tests of complex attention and executive function. These findings are suggestive of age-related, compensatory neural changes that may driven by a combination of weaker cortical efficiency and increased need for top-down control over attention. Accordingly, enhanced early OFC activity during visual attention may serve as an important indicator of frontal lobe integrity in healthy aging. PMID:27199744

  19. Effect of transcranial magnetic stimulation on single-unit activity in the cat primary visual cortex.

    PubMed

    Moliadze, Vera; Zhao, Yongqiang; Eysel, Ulf; Funke, Klaus

    2003-12-01

    Transcranial magnetic stimulation (TMS) has become a well established procedure for testing and modulating the neuronal excitability of human brain areas, but relatively little is known about the cellular processes induced by this rather coarse stimulus. In a first attempt, we performed extracellular single-unit recordings in the primary visual cortex (area 17) of the anaesthetised and paralysed cat, with the stimulating magnetic field centred at the recording site (2 x 70 mm figure-of-eight coil). The effect of single biphasic TMS pulses, which induce a lateral-to-medial electric current within the occipital pole of the right hemisphere, was tested for spontaneous as well as visually evoked activity. For cat visual cortex we found that a single TMS pulse elicited distinct episodes of enhanced and suppressed activity: in general, a facilitation of activity was found during the first 500 ms, followed thereafter by a suppression of activity lasting up to a few seconds. Strong stimuli exceeding 50 % of maximal stimulator output could also lead to an early suppression of activity during the first 100-200 ms, followed by stronger (rebound) facilitation. Early suppression and facilitation of activity may be related to a more or less direct stimulation of inhibitory and excitatory interneurons, probably with different thresholds. The late, long-lasting suppression is more likely to be related to metabotropic or metabolic processes, or even vascular responses. The time course of facilitation/inhibition may provide clues regarding the action of repetitive TMS application. PMID:12963791

  20. Immuno-localisation of anti-thyroid antibodies in adult human cerebral cortex.

    PubMed

    Moodley, Kogie; Botha, Julia; Raidoo, Deshandra Munsamy; Naidoo, Strinivasen

    2011-03-15

    Expression of thyroid-stimulating hormone receptor (TSH-R) has been demonstrated in adipocytes, lymphocytes, bone, kidney, heart, intestine and rat brain. Immuno-reactive TSH-R has been localised in rat brain and human embryonic cerebral cortex but not in adult human brain. We designed a pilot study to determine whether anti-thyroid auto-antibodies immuno-localise in normal adult human cerebral cortex. Forensic samples from the frontal, motor, sensory, occipital, cingulate and parieto-occipito-temporal association cortices were obtained from five individuals who had died of trauma. Although there were no head injuries, the prior psychiatric history of patients was unknown. The tissues were probed with commercial antibodies against both human TSH-R and human thyroglobulin (TG). Anti-TSH-R IgG immuno-localised to cell bodies and axons of large neurones in all 6 regions of all 5 brains. The intensity and percentage of neurones labelled were similar in all tissue sections. TSH-R immuno-label was also observed in vascular endothelial cells in the cingulate gyrus. Although also found in all 5 brains and all six cortical regions, TG localised exclusively in vascular smooth muscle cells and not on neurones. Although limited by the small sample size and number of brain areas examined, this is the first study describing the presence of antigenic targets for anti-TSH-R IgG on human cortical neurons, and anti-TG IgG in cerebral vasculature. PMID:21196016

  1. An Anatomical Variation of the Lesser Occipital Nerve in the “Carefree part” of the Posterior Triangle

    PubMed Central

    Sirasanagandla, Srinivasa Rao; Nayak, Satheesha B; Rao KG, Mohandas; Patil, Jyothsna

    2014-01-01

    The occurrence of the lesser occipital nerve (LON) at an anomalous location in the “carefree part” within the posterior triangle has been seldom reported in the literature. We are reporting a rare case of location of the LON in the “carefree part” of the posterior triangle, in a 55-year-old formalin embalmed male cadaver. LON, after emerging from the posterior margin of the sternomastoid muscle (SM), ran obliquely towards the trapezius muscle. Here, it hooked around the unusual separated muscle fasciculus of the trapezius, 7.5 cm below the superior nuchal line. Further, LON gave contributions to spinal accessory nerve (SAN); one deep into the SM and another one in the posterior triangle. The knowledge on the unusual location and course of the LON and its contribution to the SAN is significantly important while an anaesthetic blockade is being performed for the management of a cervicogenic headache and a super selective radical neck dissection. PMID:24959430

  2. 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

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

    PubMed

    Pea-Melin, Angel; Rosas, Antonio; Garca-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 Sidrn 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 Sidrn occipital specimens look similar to those observed in modern H. sapiens. PMID:21714107

  4. 13C MRS of occipital and frontal lobes at 3 T using a volume coil for stochastic proton decoupling

    PubMed Central

    Li, Shizhe; Zhang, Yan; Wang, Shumin; Araneta, Maria Ferraris; Johnson, Christopher S.; Xiang, Yun; Innis, Robert B.; Shen, Jun

    2011-01-01

    Previously, we devised a novel strategy for in vivo 13C MRS using [2-13C]glucose infusion and low-power proton decoupling, and proposed that this strategy could be used to acquire 13C MR spectra from the frontal lobe of the human brain. Here, we demonstrate, for the first time, in vivo 13C MRS of human frontal lobe acquired at 3 T. Because the primary metabolites of [2-13C]glucose can be decoupled using very-low-radiofrequency power, we used a volume coil for proton decoupling in this study. The homogeneous B1 field of the volume coil was found to significantly enhance the decoupling efficiency of the stochastic decoupling sequence. Detailed specific absorption rates inside the human head were analyzed using the finite difference time domain method to ensure experimental safety. In vivo 13C spectra from the occipital and frontal lobes of the human brain were obtained. At a decoupling power of 30 W (time-averaged power, 2.45 W), the spectra from the occipital lobe showed well-resolved spectral resolution and excellent signal-to-noise ratio. Although frontal lobe 13C spectra were affected by local B0 field inhomogeneity, we demonstrated that the spectral quality could be improved using post-acquisition data processing. In particular, we showed that the frontal lobe glutamine C5 at 178.5 ppm and aspartate C4 at 178.3 ppm could be spectrally resolved with effective proton decoupling and B0 field correction. Because of its large spatial coverage, volume coil decoupling provides the potential to acquire 13C MRS from more than one brain region simultaneously. PMID:20878974

  5. Dynamics of EEG rhythms support distinct visual selection mechanisms in parietal cortex: a simultaneous transcranial magnetic stimulation and EEG study.

    PubMed

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

    2015-01-14

    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-α (8-10 Hz) desynchronization contralateral to the cued location. Conversely, the transient inactivation of mSPL, compared with vIPS, reduced the high-α (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 α parieto-occipital desynchronization. Moreover, rTMS over vIPS during stay cues caused a delay of δ (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. The contributions of sensory dominance and attentional bias to cross-modal enhancement of visual cortex excitability.

    PubMed

    Romei, Vincenzo; Murray, Micah M; Cappe, Céline; Thut, Gregor

    2013-07-01

    Approaching or looming sounds (L-sounds) have been shown to selectively increase visual cortex excitability [Romei, V., Murray, M. M., Cappe, C., & Thut, G. Preperceptual and stimulus-selective enhancement of low-level human visual cortex excitability by sounds. Current Biology, 19, 1799-1805, 2009]. These cross-modal effects start at an early, preperceptual stage of sound processing and persist with increasing sound duration. Here, we identified individual factors contributing to cross-modal effects on visual cortex excitability and studied the persistence of effects after sound offset. To this end, we probed the impact of different L-sound velocities on phosphene perception postsound as a function of individual auditory versus visual preference/dominance using single-pulse TMS over the occipital pole. We found that the boosting of phosphene perception by L-sounds continued for several tens of milliseconds after the end of the L-sound and was temporally sensitive to different L-sound profiles (velocities). In addition, we found that this depended on an individual's preferred sensory modality (auditory vs. visual) as determined through a divided attention task (attentional preference), but not on their simple threshold detection level per sensory modality. Whereas individuals with "visual preference" showed enhanced phosphene perception irrespective of L-sound velocity, those with "auditory preference" showed differential peaks in phosphene perception whose delays after sound-offset followed the different L-sound velocity profiles. These novel findings suggest that looming signals modulate visual cortex excitability beyond sound duration possibly to support prompt identification and reaction to potentially dangerous approaching objects. The observed interindividual differences favor the idea that unlike early effects this late L-sound impact on visual cortex excitability is influenced by cross-modal attentional mechanisms rather than low-level sensory processes. PMID:23384192

  7. 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

  8. Right ventrolateral prefrontal cortex involvement in the integration of emotional processing: Parametric mediation analysis of fMRI.

    PubMed

    Kida, Ikuhiro; Hoshi, Yoko

    2016-02-26

    Emotion plays an important role in goal-directed behavior. Although numerous neuroimaging studies have been conducted, the neural mechanisms behind emotion generation and regulation are still elusive. This is partly explained by large individual variations in emotional responses in addition to the fact that emotion is a complex process. The present functional magnetic resonance imaging study aimed firstly to specify valence-dependent brain activation, and secondly to clarify the interactions between the regions underlying emotional processing. We measured brain activation in 12 healthy adults while passively viewing affective pictures. The individual valence ratings were negatively correlated with activation in the frontal, parietal, occipital lobes, and in the subcortical regions including the amygdalae. The parametric mediation analysis performed on these regions showed that the right ventrolateral prefrontal cortex (Brodmann area 47) was main mediator of the valence ratings with other regions. Interestingly, there was no mediator region for the ventrolateral prefrontal cortex. These results indicated the possibility that the right ventrolateral prefrontal cortex mainly participated in the integration of visually induced emotional processes in the valence dimension. PMID:26797654

  9. The selective role of premotor cortex in speech perception: a contribution to phoneme judgements but not speech comprehension.

    PubMed

    Krieger-Redwood, Katya; Gaskell, M Gareth; Lindsay, Shane; Jefferies, Elizabeth

    2013-12-01

    Several accounts of speech perception propose that the areas involved in producing language are also involved in perceiving it. In line with this view, neuroimaging studies show activation of premotor cortex (PMC) during phoneme judgment tasks; however, there is debate about whether speech perception necessarily involves motor processes, across all task contexts, or whether the contribution of PMC is restricted to tasks requiring explicit phoneme awareness. Some aspects of speech processing, such as mapping sounds onto meaning, may proceed without the involvement of motor speech areas if PMC specifically contributes to the manipulation and categorical perception of phonemes. We applied TMS to three sites-PMC, posterior superior temporal gyrus, and occipital pole-and for the first time within the TMS literature, directly contrasted two speech perception tasks that required explicit phoneme decisions and mapping of speech sounds onto semantic categories, respectively. TMS to PMC disrupted explicit phonological judgments but not access to meaning for the same speech stimuli. TMS to two further sites confirmed that this pattern was site specific and did not reflect a generic difference in the susceptibility of our experimental tasks to TMS: stimulation of pSTG, a site involved in auditory processing, disrupted performance in both language tasks, whereas stimulation of occipital pole had no effect on performance in either task. These findings demonstrate that, although PMC is important for explicit phonological judgments, crucially, PMC is not necessary for mapping speech onto meanings. PMID:23937689

  10. 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

  11. Uniplanar Nystagmus Associated with Perceptual and Cognitive Visual Dysfunction due to Presumed Focal Ischemic Occipital Cortical Atrophy: A Missed Diagnosis and New Observation

    PubMed Central

    Philip, Swetha Sara; Dutton, Gordon N.; Dorris, Liam

    2012-01-01

    Uniplanar nystagmus has been described in relation to pathology of the brain stem, retina, optic nerve, sensory visual deprivation, periventricular leucomalacia, and drug toxicity. This paper describes a case of uniplanar nystagmus associated with features of higher visual dysfunction and a presumed focal insult to the occipital lobes following an episode of neonatal apnea. PMID:23056980

  12. Abnormal Anatomical Connectivity between the Amygdala and Orbitofrontal Cortex in Conduct Disorder

    PubMed Central

    Passamonti, Luca; Fairchild, Graeme; Fornito, Alex; Goodyer, Ian M.; Nimmo-Smith, Ian; Hagan, Cindy C.; Calder, Andrew J.

    2012-01-01

    Objective Previous research suggested that structural and functional abnormalities within the amygdala and orbitofrontal cortex contribute to the pathophysiology of Conduct Disorder (CD). Here, we investigated whether the integrity of the white-matter pathways connecting these regions is abnormal and thus may represent a putative neurobiological marker for CD. Methods Diffusion Tensor Imaging (DTI) was used to investigate white-matter microstructural integrity in male adolescents with childhood-onset CD, compared with healthy controls matched in age, sex, intelligence, and socioeconomic status. Two approaches were employed to analyze DTI data: voxel-based morphometry of fractional anisotropy (FA), an index of white-matter integrity, and virtual dissection of white-matter pathways using tractography. Results Adolescents with CD displayed higher FA within the right external capsule relative to controls (T = 6.08, P<0.05, Family-Wise Error, whole-brain correction). Tractography analyses showed that FA values within the uncinate fascicle (connecting the amygdala and orbitofrontal cortex) were abnormally increased in individuals with CD relative to controls. This was in contrast with the inferior frontal-occipital fascicle, which showed no significant group differences in FA. The finding of increased FA in the uncinate fascicle remained significant when factoring out the contribution of attention-deficit/hyperactivity disorder symptoms. There were no group differences in the number of streamlines in either of these anatomical tracts. Conclusions These results provide evidence that CD is associated with white-matter microstructural abnormalities in the anatomical tract that connects the amygdala and orbitofrontal cortex, the uncinate fascicle. These results implicate abnormal maturation of white-matter pathways which are fundamental in the regulation of emotional behavior in CD. PMID:23144970

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

    PubMed

    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

  14. 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

  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. Microstructural Changes of the Baboon Cerebral Cortex during Gestational Development Reflected in MRI Diffusion Anisotropy

    PubMed Central

    Kroenke, Christopher D.; Van Essen, David C.; Inder, Terrie E.; Rees, Sandra; Bretthorst, G. Larry; Neil, Jeffrey J.

    2016-01-01

    Cerebral cortical development involves complex changes in cellular architecture and connectivity that occur at regionally varying rates. Using diffusion tensor magnetic resonance imaging (DTI) to analyze cortical microstructure, previous studies have shown that cortical maturation is associated with a progressive decline in water diffusion anisotropy. We applied high-resolution DTI to fixed postmortem fetal baboon brains and characterized regional changes in diffusion anisotropy using surface-based visualization methods. Anisotropy values vary within the thickness of the cortical sheet, being higher in superficial layers. At a regional level, anisotropy at embryonic day E90 (0.5 term; gestation lasts 185 days in this species) is low in allocortical and periallocortical regions near the frontotemporal junction and is uniformly high throughout isocortex. At E125 (0.66 term), regions having relatively low anisotropy (greater maturity) include cortex in and near the Sylvian fissure and the precentral gyrus. By E146 (0.8 term), cortical anisotropy values are uniformly low and show less regional variation. Expansion of cortical surface area does not occur uniformly in all regions. Measured using surface-based methods, cortical expansion over E125–E146 was larger in parietal, medial occipital, and lateral frontal regions than in inferior temporal, lateral occipital, and orbitofrontal regions. However, the overall correlation between the degree of cortical expansion and cortical anisotropy is modest. These results extend our understanding of cortical development revealed by histologic methods. The approach presented here can be applied in vivo to the study of normal brain development and its disruption in human infants and experimental animal models. PMID:18003829

  17. Learning and Recognition of a Non-conscious Sequence of Events in Human Primary Visual Cortex

    PubMed Central

    Rosenthal, Clive R.; Andrews, Samantha K.; Antoniades, Chrystalina A.; Kennard, Christopher; Soto, David

    2016-01-01

    Summary Human primary visual cortex (V1) has long been associated with learning simple low-level visual discriminations [1] and is classically considered outside of neural systems that support high-level cognitive behavior in contexts that differ from the original conditions of learning, such as recognition memory [2, 3]. Here, we used a novel fMRI-based dichoptic masking protocol—designed to induce activity in V1, without modulation from visual awareness—to test whether human V1 is implicated in human observers rapidly learning and then later (15–20 min) recognizing a non-conscious and complex (second-order) visuospatial sequence. Learning was associated with a change in V1 activity, as part of a temporo-occipital and basal ganglia network, which is at variance with the cortico-cerebellar network identified in prior studies of “implicit” sequence learning that involved motor responses and visible stimuli (e.g., [4]). Recognition memory was associated with V1 activity, as part of a temporo-occipital network involving the hippocampus, under conditions that were not imputable to mechanisms associated with conscious retrieval. Notably, the V1 responses during learning and recognition separately predicted non-conscious recognition memory, and functional coupling between V1 and the hippocampus was enhanced for old retrieval cues. The results provide a basis for novel hypotheses about the signals that can drive recognition memory, because these data (1) identify human V1 with a memory network that can code complex associative serial visuospatial information and support later non-conscious recognition memory-guided behavior (cf. [5]) and (2) align with mouse models of experience-dependent V1 plasticity in learning and memory [6]. PMID:26948883

  18. Learning and Recognition of a Non-conscious Sequence of Events in Human Primary Visual Cortex.

    PubMed

    Rosenthal, Clive R; Andrews, Samantha K; Antoniades, Chrystalina A; Kennard, Christopher; Soto, David

    2016-03-21

    Human primary visual cortex (V1) has long been associated with learning simple low-level visual discriminations [1] and is classically considered outside of neural systems that support high-level cognitive behavior in contexts that differ from the original conditions of learning, such as recognition memory [2, 3]. Here, we used a novel fMRI-based dichoptic masking protocol-designed to induce activity in V1, without modulation from visual awareness-to test whether human V1 is implicated in human observers rapidly learning and then later (15-20 min) recognizing a non-conscious and complex (second-order) visuospatial sequence. Learning was associated with a change in V1 activity, as part of a temporo-occipital and basal ganglia network, which is at variance with the cortico-cerebellar network identified in prior studies of "implicit" sequence learning that involved motor responses and visible stimuli (e.g., [4]). Recognition memory was associated with V1 activity, as part of a temporo-occipital network involving the hippocampus, under conditions that were not imputable to mechanisms associated with conscious retrieval. Notably, the V1 responses during learning and recognition separately predicted non-conscious recognition memory, and functional coupling between V1 and the hippocampus was enhanced for old retrieval cues. The results provide a basis for novel hypotheses about the signals that can drive recognition memory, because these data (1) identify human V1 with a memory network that can code complex associative serial visuospatial information and support later non-conscious recognition memory-guided behavior (cf. [5]) and (2) align with mouse models of experience-dependent V1 plasticity in learning and memory [6]. PMID:26948883

  19. Prefrontal cortex glutamate and extraversion.

    PubMed

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

    2012-10-01

    Extraversion is considered one of the core traits of personality. Low extraversion has been associated with increased vulnerability to affective and anxiety disorders. Brain imaging studies have linked extraversion, approach behaviour and the production of positive emotional states to the dorsolateral prefrontal cortex (DLPFC) and glutamatergic neurotransmission. However, the relationship between extraversion and glutamate in the DLPFC has not been investigated so far. In order to address this issue, absolute glutamate concentrations in the DLPFC and the visual cortex as a control region were measured by 3-Tesla proton magnetic resonance spectroscopy (1H-MRS) in 29 subjects with high and low extraversion. We found increased glutamate levels in the DLPFC of introverts as compared with extraverts. The increased glutamate concentration was specific for the DLPFC and negatively associated with state anxiety. Although preliminary, results indicate altered top-down control of DLPFC due to reduced glutamate concentration as a function of extraversion. Glutamate measurement with 1H-MRS may facilitate the understanding of biological underpinnings of personality traits and psychiatric diseases associated with dysfunctions in approach behaviour and the production of positive emotional states. PMID:22016442

  20. 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.

  1. Subspecialization in the human posterior medial cortex

    PubMed Central

    Bzdok, Danilo; Heeger, Adrian; Langner, Robert; Laird, Angela R.; Fox, Peter T.; Palomero-Gallagher, Nicola; Vogt, Brent A.; Zilles, Karl; Eickhoff, Simon B.

    2014-01-01

    The posterior medial cortex (PMC) is particularly poorly understood. Its neural activity changes have been related to highly disparate mental processes. We therefore investigated PMC properties with a data-driven exploratory approach. First, we subdivided the PMC by whole-brain coactivation profiles. Second, functional connectivity of the ensuing PMC regions was compared by task-constrained meta-analytic coactivation mapping (MACM) and task-unconstrained resting-state correlations (RSFC). Third, PMC regions were functionally described by forward/reverse functional inference. A precuneal cluster was mostly connected to the intraparietal sulcus, frontal eye fields, and right temporo-parietal junction; associated with attention and motor tasks. A ventral posterior cingulate cortex (PCC) cluster was mostly connected to the ventromedial prefrontal cortex and middle left inferior parietal cortex (IPC); associated with facial appraisal and language tasks. A dorsal PCC cluster was mostly connected to the dorsomedial prefrontal cortex, anterior/posterior IPC, posterior midcingulate cortex, and left dorsolateral prefrontal cortex; associated with delay discounting. A cluster in the retrosplenial cortex was mostly connected to the anterior thalamus and hippocampus. Furthermore, all PMC clusters were congruently coupled with the default mode network according to task-constrained but not task-unconstrained connectivity. We thus identified distinct regions in the PMC and characterized their neural networks and functional implications. PMID:25462801

  2. Subspecialization in the human posterior medial cortex.

    PubMed

    Bzdok, Danilo; Heeger, Adrian; Langner, Robert; Laird, Angela R; Fox, Peter T; Palomero-Gallagher, Nicola; Vogt, Brent A; Zilles, Karl; Eickhoff, Simon B

    2015-02-01

    The posterior medial cortex (PMC) is particularly poorly understood. Its neural activity changes have been related to highly disparate mental processes. We therefore investigated PMC properties with a data-driven exploratory approach. First, we subdivided the PMC by whole-brain coactivation profiles. Second, functional connectivity of the ensuing PMC regions was compared by task-constrained meta-analytic coactivation mapping (MACM) and task-unconstrained resting-state correlations (RSFC). Third, PMC regions were functionally described by forward/reverse functional inference. A precuneal cluster was mostly connected to the intraparietal sulcus, frontal eye fields, and right temporo-parietal junction; associated with attention and motor tasks. A ventral posterior cingulate cortex (PCC) cluster was mostly connected to the ventromedial prefrontal cortex and middle left inferior parietal cortex (IPC); associated with facial appraisal and language tasks. A dorsal PCC cluster was mostly connected to the dorsomedial prefrontal cortex, anterior/posterior IPC, posterior midcingulate cortex, and left dorsolateral prefrontal cortex; associated with delay discounting. A cluster in the retrosplenial cortex was mostly connected to the anterior thalamus and hippocampus. Furthermore, all PMC clusters were congruently coupled with the default mode network according to task-unconstrained but not task-constrained connectivity. We thus identified distinct regions in the PMC and characterized their neural networks and functional implications. PMID:25462801

  3. 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…

  4. Useful signals from motor cortex

    PubMed Central

    Schwartz, Andrew B

    2007-01-01

    Historically, the motor cortical function has been explained as a funnel to muscle activation. This invokes the idea that motor cortical neurons, or ‘upper motoneurons’, directly cause muscle contraction just like spinal motoneurons. Thus, the motor cortex and muscle activity are inextricably entwined like a puppet master and his marionette. Recently, this concept has been challenged by current experimentation showing that many behavioural aspects of action are represented in motor cortical activity. Although this activity may still be related to muscle activation, the relation between the two is likely to be indirect and complex, whereas the relation between cortical activity and kinematic parameters is simple and robust. These findings show how to extract useful signals that help explain the underlying process that generates behaviour and to harness these signals for potentially therapeutic applications. PMID:17255162

  5. 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

  6. Radiologic assessment of third molar tooth and spheno-occipital synchondrosis for age estimation: a multiple regression analysis study.

    PubMed

    Demirturk Kocasarac, Husniye; Sinanoglu, Alper; Noujeim, Marcel; Helvacioglu Yigit, Dilek; Baydemir, Canan

    2016-05-01

    For forensic age estimation, radiographic assessment of third molar mineralization is important between 14 and 21 years which coincides with the legal age in most countries. The spheno-occipital synchondrosis (SOS) is an important growth site during development, and its use for age estimation is beneficial when combined with other markers. In this study, we aimed to develop a regression model to estimate and narrow the age range based on the radiologic assessment of third molar and SOS in a Turkish subpopulation. Panoramic radiographs and cone beam CT scans of 349 subjects (182 males, 167 females) with age between 8 and 25 were evaluated. Four-stage system was used to evaluate the fusion degree of SOS, and Demirjian's eight stages of development for calcification for third molars. The Pearson correlation indicated a strong positive relationship between age and third molar calcification for both sexes (r = 0.850 for females, r = 0.839 for males, P < 0.001) and also between age and SOS fusion for females (r = 0.814), but a moderate relationship was found for males (r = 0.599), P < 0.001). Based on the results obtained, an age determination formula using these scores was established. PMID:26637329

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

    PubMed Central

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

    2014-01-01

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

  8. Vocalization Induced CFos Expression in Marmoset Cortex

    PubMed Central

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

    2010-01-01

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

  9. Ultrasonographic percutaneous anatomy of the atlanto-occipital region and indirect ultrasound-guided cisternal puncture in the dog and the cat.

    PubMed

    Etienne, A-L; Audigié, F; Peeters, D; Gabriel, A; Busoni, V

    2015-04-01

    Cisternal puncture in dogs and cats is commonly carried out. This article describes the percutaneous ultrasound anatomy of the cisternal region in the dog and the cat and an indirect technique for ultrasound-guided cisternal puncture. Ultrasound images obtained ex vivo and in vivo were compared with anatomic sections and used to identify the landmarks for ultrasound-guided cisternal puncture. The ultrasound-guided procedure was established in cadavers and then applied in vivo in seven dogs and two cats. The anatomic landmarks for the ultrasound-guided puncture are the cisterna magna, the spinal cord, the two occipital condyles on transverse images, the external occipital crest and the dorsal arch of the first cervical vertebra on longitudinal images. Using these ultrasound anatomic landmarks, an indirect ultrasound-guided technique for cisternal puncture is applicable in the dog and the cat. PMID:24712312

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

    PubMed Central

    Wiktor, Łukasz; 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

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

    PubMed

    Wiktor, Łukasz; 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

  12. Redundancy gains in retinotopic cortex

    PubMed Central

    Jiang, Yuhong V.; Kanwisher, Nancy

    2013-01-01

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

  13. 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

  14. Somatosensory responses in a human motor cortex.

    PubMed

    Shaikhouni, Ammar; Donoghue, John P; Hochberg, Leigh R

    2013-04-01

    Somatic sensory signals provide a major source of feedback to motor cortex. Changes in somatosensory systems after stroke or injury could profoundly influence brain computer interfaces (BCI) being developed to create new output signals from motor cortex activity patterns. We had the unique opportunity to study the responses of hand/arm area neurons in primary motor cortex to passive joint manipulation in a person with a long-standing brain stem stroke but intact sensory pathways. Neurons responded to passive manipulation of the contralateral shoulder, elbow, or wrist as predicted from prior studies of intact primates. Thus fundamental properties and organization were preserved despite arm/hand paralysis and damage to cortical outputs. The same neurons were engaged by attempted arm actions. These results indicate that intact sensory pathways retain the potential to influence primary motor cortex firing rates years after cortical outputs are interrupted and may contribute to online decoding of motor intentions for BCI applications. PMID:23343902

  15. Medial perirhinal cortex disambiguates confusable objects

    PubMed Central

    Tyler, Lorraine K.; Monsch, Andreas U.; Taylor, Kirsten I.

    2012-01-01

    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

  16. A layered network model of sensory cortex

    SciTech Connect

    Travis, B.J.

    1986-01-01

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

  17. Seeing with Profoundly Deactivated Mid-level Visual Areas: Non-hierarchical Functioning in the Human Visual Cortex

    PubMed Central

    Gilaie-Dotan, Sharon; Perry, Anat; Bonneh, Yoram; Malach, Rafael

    2009-01-01

    A fundamental concept in visual processing is that activity in high-order object-category distinctive regions (e.g., lateral occipital complex, fusiform face area, middle temporal+) is dependent on bottom-up flow of activity in earlier retinotopic areas (V2, V3, V4) whose main input originates from primary visual cortex (V1). Thus, activity in down stream areas should reflect lower-level inputs. Here we qualify this notion reporting case LG, a rare case of developmental object agnosia and prosopagnosia. In this person, V1 was robustly activated by visual stimuli, yet intermediate areas (V2–V4) were strongly deactivated. Despite this intermediate deactivation, activity in down stream visual areas remained robust, showing selectivity for houses and places, while selectivity for faces and objects was impaired. The extent of impairment evident in functional magnetic resonance imaging and electroencephalography activations was somewhat larger in the left hemisphere. This pattern of brain activity, coupled with fairly adequate everyday visual performance is compatible with models emphasizing the role of nonlinear local “amplification” of neuronal inputs in eliciting activity in ventral and dorsal visual pathways as well as perceptual experience in the human brain. Thus, while the proper functioning of intermediate areas appears essential for specialization in the cortex, daily visual behavior and reading are maintained even with deactivated intermediate visual areas. PMID:19015369

  18. Seeing with profoundly deactivated mid-level visual areas: non-hierarchical functioning in the human visual cortex.

    PubMed

    Gilaie-Dotan, Sharon; Perry, Anat; Bonneh, Yoram; Malach, Rafael; Bentin, Shlomo

    2009-07-01

    A fundamental concept in visual processing is that activity in high-order object-category distinctive regions (e.g., lateral occipital complex, fusiform face area, middle temporal+) is dependent on bottom-up flow of activity in earlier retinotopic areas (V2, V3, V4) whose main input originates from primary visual cortex (V1). Thus, activity in down stream areas should reflect lower-level inputs. Here we qualify this notion reporting case LG, a rare case of developmental object agnosia and prosopagnosia. In this person, V1 was robustly activated by visual stimuli, yet intermediate areas (V2-V4) were strongly deactivated. Despite this intermediate deactivation, activity in down stream visual areas remained robust, showing selectivity for houses and places, while selectivity for faces and objects was impaired. The extent of impairment evident in functional magnetic resonance imaging and electroencephalography activations was somewhat larger in the left hemisphere. This pattern of brain activity, coupled with fairly adequate everyday visual performance is compatible with models emphasizing the role of nonlinear local "amplification" of neuronal inputs in eliciting activity in ventral and dorsal visual pathways as well as perceptual experience in the human brain. Thus, while the proper functioning of intermediate areas appears essential for specialization in the cortex, daily visual behavior and reading are maintained even with deactivated intermediate visual areas. PMID:19015369

  19. Enhanced connectivity between visual cortex and other regions of the brain in autism: a REM sleep EEG coherence study.

    PubMed

    Léveillé, Cathy; Barbeau, Elise B; Bolduc, Christianne; Limoges, Elyse; Berthiaume, Claude; Chevrier, Elyse; Mottron, Laurent; Godbout, Roger

    2010-10-01

    Functional interregional neural coupling was measured as EEG coherence during REM sleep, a state of endogenous cortical activation, in 9 adult autistic individuals (21.1±4.0 years) and 13 typically developed controls (21.5±4.3 years) monitored for two consecutive nights in a sleep laboratory. Spectral analysis was performed on 60 s of artefact-free EEG samples distributed equally throughout the first four REM sleep periods of the second night. EEG coherence was calculated for six frequency bands (delta, theta, alpha, sigma, beta, and total spectrum) using a 22-electrode montage. The magnitude of coherence function was computed for intra- and interhemispheric pairs of recording sites. Results were compared by Multivariate Analysis of Variance (MANOVA). Each time the autistic group showed a greater EEG coherence than the controls; it involved intrahemispheric communication among the left visual cortex (O1) and other regions either close to or distant from the occipital cortex. In contrast, lower coherence values involved frontal electrodes in the right hemisphere. No significant differences between groups were found for interhemispheric EEG coherence. These results show that the analysis of EEG coherence during REM sleep can disclose patterns of cortical connectivity that can be reduced or increased in adults with autism compared to typically developed individuals, depending of the cortical areas studied. Superior coherence involving visual perceptual areas in autism is consistent with an enhanced role of perception in autistic brain organization. PMID:20717953

  20. Effects of alcohol administration during adulthood on parvalbumin and glial fibrillary acidic protein immunoreactivity in the rat cerebral cortex.

    PubMed

    Udomuksorn, Wandee; Mukem, Sirirak; Kumarnsit, Ekkasit; Vongvatcharanon, Surapong; Vongvatcharanon, Uraporn

    2011-05-01

    The pathology of brain atrophy mediated by alcohol was investigated in all parts of the cerebral cortex (the frontal, parietal, temporal lobes and occipital cortex) by using two markers: parvalbumin (PV) and glial fibrillary acidic protein (GFAP). Three-month old male Wistar rats were divided into control (C) and alcohol-exposed groups. The control group received distilled water, whereas the alcohol-exposed groups received either a low dose (2g/kg body wt) or a high dose (5g/kg) of ethanol for periods of 21 days, 3 or 6 months. The brains of the animals were processed for immunohistochemistry using anti-parvalbumin and anti-GFAP antibodies and the number of PV immunoreactive (PV-ir) neurons and GFAP immunoreactive (GFAP-ir) astrocytes were counted per unit area. Results showed that all groups exposed to ethanol had significantly reduced numbers of PV-ir neurons in all parts of the cerebral cortex compared to those of the control group (p<0.05). In contrast, the numbers of GFAP-ir astrocytes were increased in all parts of the cerebral cortex following the exposure to a high dose of ethanol after 21-days (but not a low dose) and both high and low doses of ethanol after 3-months or 6-months treatment compared to those of age-matched control groups (p<0.05). This indicated that in young rats (21-days), PV-ir neurons in all cerebral cortex areas seemed to be more sensitive to alcohol than GFAP-ir astrocytes. Moreover, the change in densities of both PV-ir neurons and GFAP-ir astrocytes became more apparent after exposure to prolonged and high doses of ethanol. The decrease of PV-ir neurons and the increase of GFAP-ir astrocytes indicated that alcohol may induce pathology in broad areas of the cerebral cortex. This may explain the underlying mechanism of brain atrophy and other impairments found in alcoholics. For investigations of the effects of alcohol on mediating brain pathology, we recommend the use of the two markers (PV and GFAP). PMID:20056265

  1. 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

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

    PubMed

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

    2009-12-01

    The functional specialization of the human brain means that many regions are dedicated to processing a single sensory modality. When a modality is absent, as in congenital total blindness, 'visual' regions can be reliably activated by non-visual stimuli. The connections underlying this functional adaptation, however, remain elusive. In this study, using structural and diffusion-weighted magnetic resonance imaging, we investigated the structural differences in the brains of six bilaterally anophthalmic subjects compared with sighted subjects. Surprisingly, the gross structural differences in the brains were small, even in the occipital lobe where only a small region of the primary visual cortex showed a bilateral reduction in grey matter volume in the anophthalmic subjects compared with controls. Regions of increased cortical thickness were apparent on the banks of the Calcarine sulcus, but not in the fundus. Subcortically, the white matter volume around the optic tract and internal capsule in anophthalmic subjects showed a large decrease, yet the optic radiation volume did not differ significantly. However, the white matter integrity, as measured with fractional anisotropy showed an extensive reduction throughout the brain in the anophthalmic subjects, with the greatest difference in the optic radiations. In apparent contradiction to the latter finding, the connectivity between the lateral geniculate nucleus and primary visual cortex measured with diffusion tractography did not differ between the two populations. However, these findings can be reconciled by a demonstration that at least some of the reduction in fractional anisotropy in the optic radiation is due to an increase in the strength of fibres crossing the radiations. In summary, the major changes in the 'visual' brain in anophthalmic subjects may be subcortical, although the evidence of decreased fractional anisotropy and increased crossing fibres could indicate considerable re-organization. PMID:19892766

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

    PubMed

    Falk, Dean; Lepore, Frederick E; Noe, Adrianne

    2013-04-01

    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

  4. Anticipating action effects recruits audiovisual movement representations in the ventral premotor cortex.

    PubMed

    Bischoff, Matthias; Zentgraf, Karen; Pilgramm, Sebastian; Stark, Rudolf; Krüger, Britta; Munzert, Jörn

    2014-10-29

    When table tennis players anticipate the course of the ball while preparing their motor responses, they not only observe their opponents striking the ball but also listen to events such as the sound of racket-ball contact. Because visual stimuli can be detected more easily when accompanied by a sound, we assumed that complementary sensory audiovisual information would influence the anticipation of biological motion, especially when the racket-ball contact is not presented visually, but has to be inferred from continuous movement kinematics and an abrupt sound. Twenty-six observers were examined with fMRI while watching point-light displays (PLDs) of an opposing table tennis player. Their task was to anticipate the resultant ball flight. The sound was presented complementary to the veracious event or at a deviant time point in its kinematics. Results showed that participants performed best in the complementary condition. Using a region-of-interest approach, fMRI data showed that complementary audiovisual stimulation elicited higher activation in the left temporo-occipital middle temporal gyrus (MTGto), the left primary motor cortex, and the right anterior intraparietal sulcus (aIPS). Both hemispheres also revealed higher activation in the ventral premotor cortex (vPMC) and the pars opercularis of the inferior frontal gyrus (BA 44). Ranking the behavioral effect of complementary versus conflicting audiovisual information over participants revealed an association between the complementary information and higher activation in the right vPMC. We conclude that the recruitment of movement representations in the auditory and visual modalities in the vPMC can be influenced by task-relevant cross-modal audiovisual interaction. PMID:25463138

  5. Effective Connectivity from Early Visual Cortex to Posterior Occipitotemporal Face Areas Supports Face Selectivity and Predicts Developmental Prosopagnosia

    PubMed Central

    Garrido, Lucia; Driver, Jon; Dolan, Raymond J.; Duchaine, Bradley C.; Furl, Nicholas

    2016-01-01

    Face processing is mediated by interactions between functional areas in the occipital and temporal lobe, and the fusiform face area (FFA) and anterior temporal lobe play key roles in the recognition of facial identity. Individuals with developmental prosopagnosia (DP), a lifelong face recognition impairment, have been shown to have structural and functional neuronal alterations in these areas. The present study investigated how face selectivity is generated in participants with normal face processing, and how functional abnormalities associated with DP, arise as a function of network connectivity. Using functional magnetic resonance imaging and dynamic causal modeling, we examined effective connectivity in normal participants by assessing network models that include early visual cortex (EVC) and face-selective areas and then investigated the integrity of this connectivity in participants with DP. Results showed that a feedforward architecture from EVC to the occipital face area, EVC to FFA, and EVC to posterior superior temporal sulcus (pSTS) best explained how face selectivity arises in both controls and participants with DP. In this architecture, the DP group showed reduced connection strengths on feedforward connections carrying face information from EVC to FFA and EVC to pSTS. These altered network dynamics in DP contribute to the diminished face selectivity in the posterior occipitotemporal areas affected in DP. These findings suggest a novel view on the relevance of feedforward projection from EVC to posterior occipitotemporal face areas in generating cortical face selectivity and differences in face recognition ability. SIGNIFICANCE STATEMENT Areas of the human brain showing enhanced activation to faces compared to other objects or places have been extensively studied. However, the factors leading to this face selectively have remained mostly unknown. We show that effective connectivity from early visual cortex to posterior occipitotemporal face areas gives rise to face selectivity. Furthermore, people with developmental prosopagnosia, a lifelong face recognition impairment, have reduced face selectivity in the posterior occipitotemporal face areas and left anterior temporal lobe. We show that this reduced face selectivity can be predicted by effective connectivity from early visual cortex to posterior occipitotemporal face areas. This study presents the first network-based account of how face selectivity arises in the human brain. PMID:27030766

  6. Taste in the monkey cortex.

    PubMed

    Scott, T R; Plata-Salamán, C R

    1999-10-01

    The sense of taste in humans differs substantially from that of rodents, from which a preponderance of gustatory electrophysiology derives. To establish a more appropriate neural model for human gustation, we recorded the activity of single neurons in the primary taste cortex in 11 alert cynomolgus macaques. Taste cells composed 6% of all neurons encountered. Another 24% responded during mouth and jaw movements, and 4% were sensitive to tactile stimulation of the mouth. Smaller numbers responded during olfactory or visual stimulation, or when the monkey extended his tongue. Taste cells could be divided into four statistically independent groups, corresponding to those most responsive to glucose (38%), NaCl (34%), quinine (22%), or HCI (5%). The location of a taste cell did not predict its response profile, i.e., there was no clear topographic organization of taste sensitivity. We established neural thresholds and intensity-response functions to the basic stimuli and determined that-with the exception of HCl, to which the macaque is relatively insensitive-they were similar to those reported by human subjects. We then turned to the coding of taste quality, as inferred in macaques from the patterns of neural activity elicited by each of greater than 100 stimuli. The results proved generally faithful to human reports of the perceived qualities of these same tastants. Finally, an investigation of taste mixtures revealed a degree of mixture suppression and interaction among basic qualities similar to those reported by humans. We conclude that the alert macaque offers a reliable neural model for human gustation. PMID:10549886

  7. 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

  8. 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

  9. 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

  10. Regional brain activation changes and abnormal functional connectivity of the ventrolateral prefrontal cortex during working memory processing in adults with attention-deficit/hyperactivity disorder.

    PubMed

    Wolf, Robert C; Plichta, Michael M; Sambataro, Fabio; Fallgatter, Andreas J; Jacob, Christian; Lesch, Klaus-Peter; Herrmann, Martin J; Schönfeldt-Lecuona, Carlos; Connemann, Bernhard J; Grön, Georg; Vasic, Nenad

    2009-07-01

    Previous studies on working memory (WM) function in adults with attention-deficit/hyperactivity disorder (ADHD) suggested aberrant activation of the prefrontal cortex and the cerebellum. Although it has been hypothesized that activation differences in these regions most likely reflect aberrant frontocerebellar circuits, the functional coupling of these brain networks during cognitive performance has not been investigated so far. In this study, functional magnetic resonance imaging (fMRI) and both univariate and multivariate analytic techniques were used to investigate regional activation changes and functional connectivity differences during cognitive processing in healthy controls (n = 12) and ADHD adults (n = 12). Behavioral performance during a parametric verbal WM paradigm did not significantly differ between adults with ADHD and healthy controls. During the delay period of the activation task, however, ADHD patients showed significantly less activation in the left ventrolateral prefrontal cortex (VLPFC), as well as in cerebellar and occipital regions compared with healthy control subjects. In both groups, independent component analyses revealed a functional network comprising bilateral lateral prefrontal, striatal, and cingulate regions. ADHD adults had significantly lower connectivity in the bilateral VLPFC, the anterior cingulate cortex, the superior parietal lobule, and the cerebellum compared with healthy controls. Increased connectivity in ADHD adults was found in right prefrontal regions, the left dorsal cingulate cortex and the left cuneus. These findings suggest both regional brain activation deficits and functional connectivity changes of the VLPFC and the cerebellum as well as functional connectivity abnormalities of the anterior cingulate and the parietal cortex in ADHD adults during WM processing. PMID:19107748

  11. Auditory connections and functions of prefrontal cortex

    PubMed Central

    Plakke, Bethany; Romanski, Lizabeth M.

    2014-01-01

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

  12. Ponto-geniculo-occipital-wave suppression amplifies lateral geniculate nucleus cell-size changes in monocularly deprived kittens.

    PubMed

    Shaffery, J P; Roffwarg, H P; Speciale, S G; Marks, G A

    1999-04-12

    We have previously shown that during the post-natal critical period of development of the cat visual system, 1 week of instrumental rapid eye movement (REM) sleep deprivation (IRSD) during 2 weeks of monocular deprivation (MD) results in significant amplification of the effects of solely the 2-week MD on cell-size in the binocular segment of the lateral geniculate nucleus (LGN) [36,40]. In this study, we examined whether elimination of ponto-geniculo-occipital (PGO)-wave phasic activity in the LGN during REM sleep (REMS), rather than suppression of all REMS state-related activity, would similarly yield enhanced plasticity effects on cell-size in LGN. PGO-activity was eliminated in LGN by bilateral pontomesencephalic lesions [8,32]. This method of removing phasic activation at the level of the LGN preserved sleep and wake proportions as well as the tonic activities (low voltage, fast frequency ECoG and low amplitude EMG) that characterize REM sleep. The lesions were performed in kittens on post-natal day 42, at the end of the first week of the 2-week period of MD, the same age when IRSD was started in the earlier study. LGN interlaminar cell-size disparity increased in the PGO-wave-suppressed animals as it had in behaviorally REM sleep-deprived animals. Smaller A1/A-interlaminar ratios reflect the increased disparity effect in both the REM sleep- and PGO-suppressed groups compared to animals subjected to MD-alone. With IRSD, the effect was achieved because the occluded eye-related, LGN A1-lamina cells tended to be smaller relative to their size after MD-alone, whereas after PGO-suppressing lesions, the A1-lamina cells retained their size and the non-occluded eye-related, A-lamina cells tended to be larger than after MD-alone. Despite this difference, for which several possible explanations are offered, these A1/A-interlaminar ratio data indicate that in conjunction either with suppression of the whole of the REMS state or selective removal of REM sleep phasic activity at the LGN, altered visual input evokes more LGN cell plasticity during the developmental period than it would otherwise. These data further support involvement of the REM sleep state in reducing susceptibility to plasticity changes and undesirable variability in the course of normative CNS growth and maturation. PMID:10209248

  13. Location, Location, Location: Alterations in the Functional Topography of Face- but not Object- or Place-Related Cortex in Adolescents with Autism

    PubMed Central

    Scherf, K. Suzanne; Luna, Beatriz; Minshew, Nancy; Behrmann, Marlene

    2009-01-01

    In autism, impairments in face processing are a relatively recent discovery, but have quickly become a widely accepted aspect of the behavioral profile. Only a handful of studies have investigated potential atypicalities in autism in the development of the neural substrates mediating face processing. High-functioning individuals with autism (HFA) and matched typically developing (TD) controls watched dynamic movie vignettes of faces, common objects, buildings, and scenes of navigation while undergoing an fMRI scan. With these data, we mapped the functional topography of category-selective activation for faces bilaterally in the fusiform gyrus, occipital face area, and posterior superior temporal sulcus. Additionally, we mapped category-selective activation for objects in the lateral occipital area and for places in the parahippocampal place area in the two groups. Our findings do not indicate a generalized disruption in the development of the entire ventral visual pathway in autism. Instead, our results suggest that the functional topography of face-related cortex is selectively disrupted in autism and that this alteration is present in early adolescence. Furthermore, for those HFA adolescents who do exhibit face-selective activation, this activation tends to be located in traditionally object-related regions, which supports the hypothesis that perceptual processing of faces in autism may be more akin to the perceptual processing of common objects in TD individuals. PMID:20631857

  14. 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

    2015-01-01

    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

  15. The functions of the orbitofrontal cortex.

    PubMed

    Rolls, Edmund T

    2004-06-01

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

  16. Dissociating motor cortex from the motor

    PubMed Central

    Schieber, Marc H

    2011-01-01

    Abstract During closed-loop control of a brain–computer interface, neurons in the primary motor cortex can be intensely active even though the subject may be making no detectable movement or muscle contraction. How can neural activity in the primary motor cortex become dissociated from the movements and muscles of the native limb that it normally controls? Here we examine circumstances in which motor cortex activity is known to dissociate from movement – including mental imagery, visuo-motor dissociation and instructed delay. Many such motor cortex neurons may be related to muscle activity only indirectly. Furthermore, the integration of thousands of synaptic inputs by individual α-motoneurons means that under certain circumstances even cortico-motoneuronal cells, which make monosynaptic connections to α-motoneurons, can become dissociated from muscle activity. The natural ability of motor cortex neurons under voluntarily control to become dissociated from bodily movement may underlie the utility of this cortical area for controlling brain–computer interfaces. PMID:22005673

  17. [Numerical taxonomy of corlor in Phellodendron Cortex].

    PubMed

    Jin, Yan; Huang, Lu-qi; Yuan, Yuan; Zhang, Shan-shan; Jin, Shi-yuan

    2015-10-01

    Through the investigation of Phellodendron Cortex on the market, and 28 batches of samples were collected. By using spectrophotometer the color values of outer surface, inner surface and cross - section of these samples were measured. These measured color data was translated into 3D structure diagram by using the Lab color space tool. The level difference value, the mean value and the threshold value were calculated based the measured color data of these different batches of samples. All 28 groups measured data was analyzed using the methods of Ward linkage and average Euclidean distance. At the same time, we invited Professor Jin Shiyuan, the "Chinese medicine master", to identify, quality-evaluate and grade these 28 batches of Phellodendron Cortex samples base on the traditional experience, then compared the traditional empirical results with the spectrophotometer measurement results. The result showed that, the Phellodendron Cortex could be divided into Phellodendri Amurensis Cortex and Phellodendri Chinensis Cortex by color numerical clustering, and classified according to quality. The classification result has a high degree of consistency with the traditional experience. PMID:26975099

  18. Dissociating motor cortex from the motor.

    PubMed

    Schieber, Marc H

    2011-12-01

    During closed-loop control of a brain-computer interface, neurons in the primary motor cortex can be intensely active even though the subject may be making no detectable movement or muscle contraction. How can neural activity in the primary motor cortex become dissociated from the movements and muscles of the native limb that it normally controls? Here we examine circumstances in which motor cortex activity is known to dissociate from movement--including mental imagery, visuo-motor dissociation and instructed delay. Many such motor cortex neurons may be related to muscle activity only indirectly. Furthermore, the integration of thousands of synaptic inputs by individual α-motoneurons means that under certain circumstances even cortico-motoneuronal cells, which make monosynaptic connections to α-motoneurons, can become dissociated from muscle activity. The natural ability of motor cortex neurons under voluntarily control to become dissociated from bodily movement may underlie the utility of this cortical area for controlling brain-computer interfaces. PMID:22005673

  19. Damage to left anterior temporal cortex predicts impairment of complex syntactic processing: a lesion-symptom mapping study.

    PubMed

    Magnusdottir, S; Fillmore, P; den Ouden, D B; Hjaltason, H; Rorden, C; Kjartansson, O; Bonilha, L; Fridriksson, J

    2013-10-01

    Sentence processing problems form a common consequence of left-hemisphere brain injury, in some patients to such an extent that their pattern of language performance is characterized as "agrammatic". However, the location of left-hemisphere damage that causes such problems remains controversial. It has been suggested that the critical site for syntactic processing is Broca's area of the frontal cortex or, alternatively, that a more widely distributed network is responsible for syntactic processing. The aim of this study was to identify brain regions that are required for successful sentence processing. Voxel-based lesion-symptom mapping (VLSM) was used to identify brain regions where injury predicted impaired sentence processing in 50 native speakers of Icelandic with left-hemisphere stroke. Sentence processing was assessed by having individuals identify which picture corresponded to a verbally presented sentence. The VLSM analysis revealed that impaired sentence processing was best predicted by damage to a large left-hemisphere temporo-parieto-occipital area. This is likely due to the multimodal nature of the sentence processing task, which involves auditory and visual analysis, as well as lexical and syntactic processing. Specifically impaired processing of noncanonical sentence types, when compared with canonical sentence processing, was associated with damage to the left-hemisphere anterior superior and middle temporal gyri and the temporal pole. Anterior temporal cortex, therefore, appears to play a crucial role in syntactic processing, and patients with brain damage to this area are more likely to present with receptive agrammatism than patients in which anterior temporal cortex is spared. PMID:22522937

  20. 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

  1. 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

  2. Feedforward and feedback projections of caudal belt and parabelt areas of auditory cortex: refining the hierarchical model

    PubMed Central

    Hackett, Troy A.; de la Mothe, Lisa A.; Camalier, Corrie R.; Falchier, Arnaud; Lakatos, Peter; Kajikawa, Yoshinao; Schroeder, Charles E.

    2014-01-01

    Our working model of the primate auditory cortex recognizes three major regions (core, belt, parabelt), subdivided into thirteen areas. The connections between areas are topographically ordered in a manner consistent with information flow along two major anatomical axes: core-belt-parabelt and caudal-rostral. Remarkably, most of the connections supporting this model were revealed using retrograde tracing techniques. Little is known about laminar circuitry, as anterograde tracing of axon terminations has rarely been used. The purpose of the present study was to examine the laminar projections of three areas of auditory cortex, pursuant to analysis of all areas. The selected areas were: middle lateral belt (ML); caudomedial belt (CM); and caudal parabelt (CPB). Injections of anterograde tracers yielded data consistent with major features of our model, and also new findings that compel modifications. Results supporting the model were: (1) feedforward projection from ML and CM terminated in CPB; (2) feedforward projections from ML and CPB terminated in rostral areas of the belt and parabelt; and (3) feedback projections typified inputs to the core region from belt and parabelt. At odds with the model was the convergence of feedforward inputs into rostral medial belt from ML and CPB. This was unexpected since CPB is at a higher stage of the processing hierarchy, with mainly feedback projections to all other belt areas. Lastly, extending the model, feedforward projections from CM, ML, and CPB overlapped in the temporal parietal occipital area (TPO) in the superior temporal sulcus, indicating significant auditory influence on sensory processing in this region. The combined results refine our working model and highlight the need to complete studies of the laminar inputs to all areas of auditory cortex. Their documentation is essential for developing informed hypotheses about the neurophysiological influences of inputs to each layer and area. PMID:24795550

  3. 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.

  4. Mapping receptive fields in primary visual cortex.

    PubMed

    Ringach, Dario L

    2004-08-01

    Nearly 40 years ago, in the pages of this journal, Hubel and Wiesel provided the first description of receptive fields in the primary visual cortex of higher mammals. They defined two classes of cortical cells, "simple" and "complex", based on neural responses to simple visual stimuli. The notion of a hierarchy of receptive fields, where increasingly intricate receptive fields are constructed from more elementary ones, was introduced. Since those early days we have witnessed the birth of quantitative methods to map receptive fields and mathematical descriptions of simple and complex cell function. Insights gained from these models, along with new theoretical concepts, are refining our understanding of receptive field structure and the underlying cortical circuitry. Here, I provide a brief historical account of the evolution of receptive field mapping in visual cortex along with the associated conceptual advancements, and speculate on the shape novel theories of the cortex may take as a result these measurements. PMID:15155794

  5. Heterogeneous reward signals in prefrontal cortex

    PubMed Central

    Wallis, Jonathan D.; Kennerley, Steven W.

    2010-01-01

    Summary Neurons encode upcoming rewards throughout frontal cortex. Recent papers have helped to determine that these signals play different roles in different frontal regions. Neurons in orbitofrontal cortex (PFo) appear to be responsible for calculating the specific value of an expected reward, information that can help efficiently guide decision-making. Similar signals are also present in the cingulate sulcus (PFcs). In contrast, reward signals in lateral prefrontal cortex (PFl) are consistent with a role in using reward to guide other cognitive processes, such as the allocation of attentional resources and using value information to guide learning other relationships in the environment such as arbitrary stimulus-response mappings. A remaining issue for future work is to specify the precise roles of PFo and PFcs. These two areas show very different patterns of connectivity with other brain areas, and it is currently unclear how this effects their contribution to decision-making. PMID:20303739

  6. 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.

  7. Cortex commands the performance of skilled movement

    PubMed Central

    Guo, Jian-Zhong; Graves, Austin R; Guo, Wendy W; Zheng, Jihong; Lee, Allen; Rodríguez-González, Juan; Li, Nuo; Macklin, John J; Phillips, James W; Mensh, Brett D; Branson, Kristin; Hantman, Adam W

    2015-01-01

    Mammalian cerebral cortex is accepted as being critical for voluntary motor control, but what functions depend on cortex is still unclear. Here we used rapid, reversible optogenetic inhibition to test the role of cortex during a head-fixed task in which mice reach, grab, and eat a food pellet. Sudden cortical inhibition blocked initiation or froze execution of this skilled prehension behavior, but left untrained forelimb movements unaffected. Unexpectedly, kinematically normal prehension occurred immediately after cortical inhibition, even during rest periods lacking cue and pellet. This ‘rebound’ prehension was only evoked in trained and food-deprived animals, suggesting that a motivation-gated motor engram sufficient to evoke prehension is activated at inhibition’s end. These results demonstrate the necessity and sufficiency of cortical activity for enacting a learned skill. DOI: http://dx.doi.org/10.7554/eLife.10774.001 PMID:26633811

  8. Increased activities of Na+/K+-ATPase and Ca2+/Mg2+-ATPase in the frontal cortex and cerebellum of autistic individuals

    PubMed Central

    Ji, Lina; Chauhan, Abha; Brown, W. Ted; Chauhan, Ved

    2009-01-01

    Aims Na+/K+-ATPase and Ca2+/Mg2+-ATPase are enzymes known to maintain intracellular gradients of ions that are essential for signal transduction. The aim of this study was to compare the activities of Na+/K+-ATPase and Ca2+/Mg2+-ATPase in post-mortem brain samples from the cerebellum and frontal, temporal, parietal, and occipital cortices from autistic and age-matched control subjects. Main methods The frozen postmortem tissues from different brain regions of autistic and control subjects were homogenized. The activities of Na+/K+-ATPase and Ca2+/Mg2+-ATPase were assessed in the brain homogenates by measuring inorganic phosphorus released by the action of Na+/K+- and Ca2+/Mg2+- dependent hydrolysis of ATP. Key findings In the cerebellum, the activities of both Na+/K+-ATPase and Ca2+/Mg2+-ATPase were significantly increased in the autistic samples compared with their age-matched controls. The activity of Na+/K+-ATPase but not Ca2+/Mg2+-ATPase was also significantly increased in the frontal cortex of the autistic samples as compared to the age-matched controls. In contrast, in other regions, i.e., the temporal, parietal and occipital cortices, the activities of these enzymes were similar in autism and control groups. Significance The results of this study suggest brain-region specific increases in the activities of Na+/K+-ATPase and Ca2+/Mg2+-ATPase in autism. Increased activity of these enzymes in the frontal cortex and cerebellum may be due to compensatory responses to increased intracellular calcium concentration in autism. We suggest that altered activities of these enzymes may contribute to abnormal neuronal circuit functioning in autism. PMID:19863947

  9. Rapid fluctuations in rat barrel cortex plasticity.

    PubMed

    Erchova, Irina A; Diamond, Mathew E

    2004-06-30

    Neuronal populations in the sensory cortex exhibit fluctuations in excitability, and the present experiments tested the hypothesis that these variations coincide with peaks and troughs in cortical modifiability. The activity of multiunit neuronal clusters under light urethane anesthesia was recorded through 100-microelectrode arrays implanted in the infragranular layers of rat barrel cortex. Spontaneous activity was characterized by "bursts" of spikes, synchronized across the barrel cortex. This allowed activity at one selected electrode to be taken as a reliable monitor of widespread cortical bursts. We used spikes at the selected electrode to trigger stimulation of two pairs of whiskers during a 50 min conditioning procedure: (1) for the "burst-conditioned" whisker pair, each stimulus was delivered 1 msec after the triggering spike, activating cortex coincident with the burst; and (2) for the "interburst-conditioned" whisker pair, each stimulus was delivered 300 msec after the triggering spike, activating cortex during the trough between bursts. The cross-correlation between cortical neurons in the pairs of columns matching the stimulated whisker pairs was estimated after the termination of the conditioning procedure. Conditioning produced a twofold increase in the degree of co-firing between infragranular neurons in columns receiving burst-conditioned costimulation but no significant change in connectivity between infragranular neurons in columns receiving interburst-conditioned costimulation, although the two pairs of columns received an equal number of sensory inputs. These findings suggest that the strength of co-activity between columns in the barrel cortex can be modified by sensory input patterns during discrete, intermittent intervals time-locked to bursts. PMID:15229241

  10. Measuring the Dynamic Longitudinal Cortex Development in Infants by Reconstruction of Temporally Consistent Cortical Surfaces

    PubMed Central

    Li, Gang; Nie, Jingxin; Wang, Li; Shi, Feng; Gilmore, John H.; Lin, Weili; Shen, Dinggang

    2014-01-01

    Quantitative measurement of the dynamic longitudinal cortex development during early postnatal stages is of great importance to understand the early cortical structural and functional development. Conventional methods usually reconstruct the cortical surfaces of longitudinal images from the same subject independently, which often generate longitudinally-inconsistent cortical surfaces and thus lead to inaccurate measurement of cortical changes, especially for vertex-wise mapping of cortical development. This paper aims to address this problem by presenting a method to reconstruct temporally-consistent cortical surfaces from longitudinal infant brain MR images, for accurate and consistent measurement of the dynamic cortex development in infants. Specifically, the longitudinal development of the inner cortical surface is first modeled by a deformable growth sheet with elasto-plasticity property to establish longitudinally smooth correspondences of the inner cortical surfaces. Then, the modeled longitudinal inner cortical surfaces are jointly deformed to locate both inner and outer cortical surfaces with a spatial-temporal deformable surface method. The method has been applied to 13 healthy infants, each with 6 serial MR scans acquired at 2 weeks, 3 months, 6 months, 9 months, 12 months and 18 months of age. Experimental results showed that our method with the incorporated longitudinal constraints can reconstruct the longitudinally-dynamic cortical surfaces from serial infant MR images more consistently and accurately than the previously published methods. By using our method, for the first time, we can characterize the vertex-wise longitudinal cortical thickness development trajectory at multiple time points in the first 18 months of life. Specifically, we found the highly age-related and regionally-heterogeneous developmental trajectories of the cortical thickness during this period, with the cortical thickness increased most from 3 to 6 months (16.2%) and least from 9 to 12 months (less than 0.1%). Specifically, the central sulcus only underwent significant increase of cortical thickness from 6 to 9 months and the occipital cortex underwent significant increase from 0 to 9 months, while the frontal, temporal and parietal cortices grew continuously in this first 18 months of life. The adult-like spatial patterns of cortical thickness were generally present at 18 months of age. These results provided detailed insights into the dynamic trajectory of the cortical thickness development in infants. PMID:24374075

  11. 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

  12. Coding of movements in the motor cortex.

    PubMed

    Georgopoulos, Apostolos P; Carpenter, Adam F

    2015-08-01

    The issue of coding of movement in the motor cortex has recently acquired special significance due to its fundamental importance in neuroprosthetic applications. The challenge of controlling a prosthetic arm by processed motor cortical activity has opened a new era of research in applied medicine but has also provided an 'acid test' for hypotheses regarding coding of movement in the motor cortex. The successful decoding of movement information from the activity of motor cortical cells using their directional tuning and population coding has propelled successful neuroprosthetic applications and, at the same time, asserted the utility of those early discoveries, dating back to the early 1980s. PMID:25646932

  13. 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

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

    NASA Astrophysics Data System (ADS)

    Schwarz, J. M.

    Despite decades of research, there is still no consensus regarding the mechanism(s) driving cerebral cortex folding. Two different mechanisms--axonal tension based on efficient wiring of the neurons and differential growth-induced buckling--are the prevailing hypotheses, though quantitative comparison with data raises issues with both of them. I will present a model for the elasticity of the cerebral cortex as a layered material with bending energy along the layers and elastic energy between them. 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 undulations emerge, i.e. a buckling instability occurs, to presumably initiate folds in the cortex. This model builds on the original axonal tension model for cortex folding based on the efficient wiring of neurons but with no buckling mechanism and allows one to understand why small mice brains exhibit no folds, while larger human brains do. Finally, an estimate of the bending rigidity constant for the cortex can be made based on the critical wavelength to quantitatively test this revised axonal tensional model. This work was done in collaboration with Oksana Manyuhina and David Mayett.

  15. Prefrontal Cortex and Somatosensory Cortex in Tactile Crossmodal Association: An Independent Component Analysis of ERP Recordings

    PubMed Central

    Wang, Liping; Lenz, Fred A.; Hsiao, Steven S.; Bodner, Mark; Hong, Bo; Zhou, Yong-Di

    2007-01-01

    Our previous studies on scalp-recorded event-related potentials (ERPs) showed that somatosensory N140 evoked by a tactile vibration in working memory tasks was enhanced when human subjects expected a coming visual stimulus that had been paired with the tactile stimulus. The results suggested that such enhancement represented the cortical activities involved in tactile-visual crossmodal association. In the present study, we further hypothesized that the enhancement represented the neural activities in somatosensory and frontal cortices in the crossmodal association. By applying independent component analysis (ICA) to the ERP data, we found independent components (ICs) located in the medial prefrontal cortex (around the anterior cingulate cortex, ACC) and the primary somatosensory cortex (SI). The activity represented by the IC in SI cortex showed enhancement in expectation of the visual stimulus. Such differential activity thus suggested the participation of SI cortex in the task-related crossmodal association. Further, the coherence analysis and the Granger causality spectral analysis of the ICs showed that SI cortex appeared to cooperate with ACC in attention and perception of the tactile stimulus in crossmodal association. The results of our study support with new evidence an important idea in cortical neurophysiology: higher cognitive operations develop from the modality-specific sensory cortices (in the present study, SI cortex) that are involved in sensation and perception of various stimuli. PMID:17712419

  16. 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

  17. 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…

  18. 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…

  19. 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

  20. Lateral prefrontal cortex: architectonic and functional organization

    PubMed Central

    Petrides, Michael

    2005-01-01

    A comparison of the architecture of the human prefrontal cortex with that of the macaque monkey showed a very similar architectonic organization in these two primate species. There is no doubt that the prefrontal cortical areas of the human brain have undergone considerable development, but it is equally clear that the basic architectonic organization is the same in the two species. Thus, a comparative approach to the study of the functional organization of the primate prefrontal cortex is more likely to reveal the essential aspects of the various complex control processes that are the domain of frontal function. The lateral frontal cortex appears to be functionally organized along both a rostral–caudal axis and a dorsal–ventral axis. The most caudal frontal region, the motor region on the precentral gyrus, is involved in fine motor control and direct sensorimotor mappings, whereas the caudal lateral prefrontal region is involved in higher order control processes that regulate the selection among multiple competing responses and stimuli based on conditional operations. Further rostrally, the mid-lateral prefrontal region plays an even more abstract role in cognitive control. The mid-lateral prefrontal region is itself organized along a dorsal–ventral axis of organization, with the mid-dorsolateral prefrontal cortex being involved in the monitoring of information in working memory and the mid-ventrolateral prefrontal region being involved in active judgments on information held in posterior cortical association regions that are necessary for active retrieval and encoding of information. PMID:15937012

  1. 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…

  2. 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

  3. The harmonic organization of auditory cortex

    PubMed Central

    Wang, Xiaoqin

    2013-01-01

    A fundamental structure of sounds encountered in the natural environment is the harmonicity. Harmonicity is an essential component of music found in all cultures. It is also a unique feature of vocal communication sounds such as human speech and animal vocalizations. Harmonics in sounds are produced by a variety of acoustic generators and reflectors in the natural environment, including vocal apparatuses of humans and animal species as well as music instruments of many types. We live in an acoustic world full of harmonicity. Given the widespread existence of the harmonicity in many aspects of the hearing environment, it is natural to expect that it be reflected in the evolution and development of the auditory systems of both humans and animals, in particular the auditory cortex. Recent neuroimaging and neurophysiology experiments have identified regions of non-primary auditory cortex in humans and non-human primates that have selective responses to harmonic pitches. Accumulating evidence has also shown that neurons in many regions of the auditory cortex exhibit characteristic responses to harmonically related frequencies beyond the range of pitch. Together, these findings suggest that a fundamental organizational principle of auditory cortex is based on the harmonicity. Such an organization likely plays an important role in music processing by the brain. It may also form the basis of the preference for particular classes of music and voice sounds. PMID:24381544

  4. Maps of optical differential pathlength factor of human adult forehead, somatosensory motor and occipital regions at multi-wavelengths in NIR

    NASA Astrophysics Data System (ADS)

    Zhao, Huijuan; Tanikawa, Yukari; Gao, Feng; Onodera, Yoichi; Sassaroli, Angelo; Tanaka, Kenji; Yamada, Yukio

    2002-06-01

    The optical differential pathlength factor (DPF) is an important parameter for physiological measurement using near infrared spectroscopy, but for the human adult head it has been available only for the forehead. Here we report measured DPF results for the forehead, somatosensory motor and occipital regions from measurements on 11 adult volunteers using a time-resolved optical imaging system. The optode separation was about 30 mm and the wavelengths used were 759 nm, 799 nm and 834 nm. Measured DPFs were 7.25 for the central forehead and 6.25 for the temple region at 799 nm. For the central somatosensory and occipital areas (10 mm above the inion), DPFs at 799 nm are 7.5 and 8.75, respectively. Less than 10% decreases of DPF for all these regions were observed when the wavelength increased from 759 nm to 834 nm. To compare these DPF maps with the anatomical structure of the head, a Monte Carlo simulation was carried out to calculate DPF for these regions by using a two-layered semi-infinite model and assuming the thickness of the upper layer to be the sum of the thicknesses of scalp and skull, which was measured from MRI images of a subject's head. The DPF data will be useful for quantitative monitoring of the haemodynamic changes occurring in adult heads.

  5. Quantitative analyses of postmortem heat shock protein mRNA profiles in the occipital lobes of human cerebral cortices: implications in cause of death.

    PubMed

    Chung, Ukhee; Seo, Joong-Seok; Kim, Yu-Hoon; Son, Gi Hoon; Hwang, Juck-Joon

    2012-11-01

    Quantitative RNA analyses of autopsy materials to diagnose the cause and mechanism of death are challenging tasks in the field of forensic molecular pathology. Alterations in mRNA profiles can be induced by cellular stress responses during supravital reactions as well as by lethal insults at the time of death. Here, we demonstrate that several gene transcripts encoding heat shock proteins (HSPs), a gene family primarily responsible for cellular stress responses, can be differentially expressed in the occipital region of postmortem human cerebral cortices with regard to the cause of death. HSPA2 mRNA levels were higher in subjects who died due to mechanical asphyxiation (ASP), compared with those who died by traumatic injury (TI). By contrast, HSPA7 and A13 gene transcripts were much higher in the TI group than in the ASP and sudden cardiac death (SCD) groups. More importantly, relative abundances between such HSP mRNA species exhibit a stronger correlation to, and thus provide more discriminative information on, the death process than does routine normalization to a housekeeping gene. Therefore, the present study proposes alterations in HSP mRNA composition in the occipital lobe as potential forensic biological markers, which may implicate the cause and process of death. PMID:23135635

  6. Quantitative Analyses of Postmortem Heat Shock Protein mRNA Profiles in the Occipital Lobes of Human Cerebral Cortices: Implications in Cause of Death

    PubMed Central

    Chung, Ukhee; Seo, Joong-Seok; Kim, Yu-Hoon; Son, Gi Hoon; Hwang, Juck-Joon

    2012-01-01

    Quantitative RNA analyses of autopsy materials to diagnose the cause and mechanism of death are challenging tasks in the field of forensic molecular pathology. Alterations in mRNA profiles can be induced by cellular stress responses during supravital reactions as well as by lethal insults at the time of death. Here, we demonstrate that several gene transcripts encoding heat shock proteins (HSPs), a gene family primarily responsible for cellular stress responses, can be differentially expressed in the occipital region of postmortem human cerebral cortices with regard to the cause of death. HSPA2 mRNA levels were higher in subjects who died due to mechanical asphyxiation (ASP), compared with those who died by traumatic injury (TI). By contrast, HSPA7 and A13 gene transcripts were much higher in the TI group than in the ASP and sudden cardiac death (SCD) groups. More importantly, relative abundances between such HSP mRNA species exhibit a stronger correlation to, and thus provide more discriminative information on, the death process than does routine normalization to a housekeeping gene. Therefore, the present study proposes alterations in HSP mRNA composition in the occipital lobe as potential forensic biological markers, which may implicate the cause and process of death. PMID:23135635

  7. Cerebral Cortex Structure in Prodromal Huntington Disease

    PubMed Central

    Nopoulos, Peggy C.; Aylward, Elizabeth H.; Ross, Christopher A.; Johnson, Hans J.; Magnotta, Vincent A.; Juhl, Andrew R.; Pierson, Ronald K.; Mills, James; Langbehn, Douglas R.; Paulsen, Jane S.

    2010-01-01

    Neuroimaging studies of subjects who are gene-expanded for Huntington Disease, but not yet diagnosed (termed prodromal HD), report that the cortex is “spared,” despite the decrement in striatal and cerebral white-matter volume. Measurement of whole-cortex volume can mask more subtle, but potentially clinically relevant regional changes in volume, thinning, or surface area. The current study addressed this limitation by evaluating cortical morphology of 523 prodromal HD subjects. Participants included 693 individuals enrolled in the PREDICT-HD protocol. Of these participants, 523 carried the HD gene mutation (prodromal HD group); the remaining 170 were non gene-expanded and served as the comparison group. Based on age and CAG repeat length, gene-expanded subjects were categorized as “Far from onset,” “Midway to onset,” “Near onset,” and “already diagnosed.” MRI scans were processed using FreeSurfer. Cortical volume, thickness, and surface area were not significantly different between the Far from onset group and controls. However, beginning in the Midway to onset group, the cortex showed significant volume decrement, affecting most the posterior and superior cerebral regions. This pattern progressed when evaluating the groups further into the disease process. Areas that remained mostly unaffected included ventral and medial regions of the frontal and temporal cortex. Morphologic changes were mostly in thinning as surface area did not substantially change in most regions. Early in the course of HD, the cortex shows changes that are manifest as cortical thinning and are most robust in the posterior and superior regions of the cerebrum. PMID:20688164

  8. Studies on brain-cortex slices

    PubMed Central

    Cremer, Jill E.

    1967-01-01

    1. The K+ content of brain-cortex slices incubated in a Krebs–Ringer phosphate medium was the same whether the substrate was glucose (11mm) or pyruvate (11mm). 2. 2,4-Dinitrophenol (30μm) and ouabain (83μm) lowered the K+ content of brain-cortex slices by approx. 40% with either glucose or pyruvate as the substrate. Triethyltin (1·3μm) lowered the K+ content by 73% with glucose as substrate, but by only 18% when the substrate was pyruvate. 3. Quantitative estimations of six individual amino acids were made on brain-cortex slices and on the incubation medium after 75min. at 37°. Some differences were found depending on whether the substrate was glucose or pyruvate. The effects of 2,4-dinitrophenol, oligomycin, triethyltin and ouabain were studied. Triethyltin caused a marked increase in the medium of each amino acid when the substrate was glucose, but not when it was pyruvate. Ouabain caused a similar increase with either glucose or pyruvate as substrate. 4. The uptake of triethyltin by brain-cortex slices was measured by using radioactive triethyl[113Sn]tin chloride. Various experimental conditions did not alter the uptake; these included adding glucose or pyruvate as a substrate. 5. From the author's own results and those of others it is suggested that pyruvate is an unsuitable substrate to use for the study of regulatory factors of endogenous pyruvate metabolism in brain-cortex slices. Glucose is preferable. PMID:6035513

  9. Cerebral cortex structure in prodromal Huntington disease.

    PubMed

    Nopoulos, Peggy C; Aylward, Elizabeth H; Ross, Christopher A; Johnson, Hans J; Magnotta, Vincent A; Juhl, Andrew R; Pierson, Ronald K; Mills, James; Langbehn, Douglas R; Paulsen, Jane S

    2010-12-01

    Neuroimaging studies of subjects who are gene-expanded for Huntington Disease, but not yet diagnosed (termed prodromal HD), report that the cortex is "spared," despite the decrement in striatal and cerebral white-matter volume. Measurement of whole-cortex volume can mask more subtle, but potentially clinically relevant regional changes in volume, thinning, or surface area. The current study addressed this limitation by evaluating cortical morphology of 523 prodromal HD subjects. Participants included 693 individuals enrolled in the PREDICT-HD protocol. Of these participants, 523 carried the HD gene mutation (prodromal HD group); the remaining 170 were non gene-expanded and served as the comparison group. Based on age and CAG repeat length, gene-expanded subjects were categorized as "Far from onset," "Midway to onset," "Near onset," and "already diagnosed." MRI scans were processed using FreeSurfer. Cortical volume, thickness, and surface area were not significantly different between the Far from onset group and controls. However, beginning in the Midway to onset group, the cortex showed significant volume decrement, affecting most the posterior and superior cerebral regions. This pattern progressed when evaluating the groups further into the disease process. Areas that remained mostly unaffected included ventral and medial regions of the frontal and temporal cortex. Morphologic changes were mostly in thinning as surface area did not substantially change in most regions. Early in the course of HD, the cortex shows changes that are manifest as cortical thinning and are most robust in the posterior and superior regions of the cerebrum. PMID:20688164

  10. 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)

  11. Neural Substrates of Visual Spatial Coding and Visual Feedback Control for Hand Movements in Allocentric and Target-Directed Tasks

    PubMed Central

    Thaler, Lore; Goodale, Melvyn A.

    2011-01-01

    Neuropsychological evidence suggests that different brain areas may be involved in movements that are directed at visual targets (e.g., pointing or reaching), and movements that are based on allocentric visual information (e.g., drawing or copying). Here we used fMRI to investigate the neural correlates of these two types of movements in healthy volunteers. Subjects (n = 14) performed right hand movements in either a target-directed task (moving a cursor to a target dot) or an allocentric task (moving a cursor to reproduce the distance and direction between two distal target dots) with or without visual feedback about their hand movement. Movements were monitored with an MR compatible touch panel. A whole brain analysis revealed that movements in allocentric conditions led to an increase in activity in the fundus of the left intra-parietal sulcus (IPS), in posterior IPS, in bilateral dorsal premotor cortex (PMd), and in the lateral occipital complex (LOC). Visual feedback in both target-directed and allocentric conditions led to an increase in activity in area MT+, superior parietal–occipital cortex (SPOC), and posterior IPS (all bilateral). In addition, we found that visual feedback affected brain activity differently in target-directed as compared to allocentric conditions, particularly in the pre-supplementary motor area, PMd, IPS, and parieto-occipital cortex. Our results, in combination with previous findings, suggest that the LOC is essential for allocentric visual coding and that SPOC is involved in visual feedback control. The differences in brain activity between target-directed and allocentric visual feedback conditions may be related to behavioral differences in visual feedback control. Our results advance the understanding of the visual coordinate frame used by the LOC. In addition, because of the nature of the allocentric task, our results have relevance for the understanding of neural substrates of magnitude estimation and vector coding of movements. PMID:21941474

  12. [The Role of Insular Cortex in Autonomic Control].

    PubMed

    Aleksandrov, V G; Aleksandrova, N P

    2015-01-01

    The purpose of this article is to review experimental data proving that the insular cortex is involved in the regulation of visceral systems: respiratory, cardiovascular and gastrointestinal systems. The paper deals with the data on the structure of the insular cortex, the pathways in brain by which visceral information ascend to the insular cortex, the results of neurophysiological experiments and clinical observations. The experimental evidence of viscerotopical organization of not only sensor, but also motor representation of visceral systems in the insular cortex is discussed. On the basis of these data the insular cortex is defined as sensorimotor visceral cortex. It is demonstrated that one of the mechanisms of influence of the insular cortex on the regulation of internal organs is the modulation of reflex reactions which take place at the bulbar level. PMID:26601415

  13. The auditory representation of speech sounds in human motor cortex.

    PubMed

    Cheung, Connie; Hamiton, Liberty S; Johnson, Keith; Chang, Edward F

    2016-01-01

    In humans, listening to speech evokes neural responses in the motor cortex. This has been controversially interpreted as evidence that speech sounds are processed as articulatory gestures. However, it is unclear what information is actually encoded by such neural activity. We used high-density direct human cortical recordings while participants spoke and listened to speech sounds. Motor cortex neural patterns during listening were substantially different than during articulation of the same sounds. During listening, we observed neural activity in the superior and inferior regions of ventral motor cortex. During speaking, responses were distributed throughout somatotopic representations of speech articulators in motor cortex. The structure of responses in motor cortex during listening was organized along acoustic features similar to auditory cortex, rather than along articulatory features as during speaking. Motor cortex does not contain articulatory representations of perceived actions in speech, but rather, represents auditory vocal information. PMID:26943778

  14. Anterior insular cortex and emotional awareness.

    PubMed

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

    2013-10-15

    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

  15. 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

  16. 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

  17. Social Distance Evaluation in Human Parietal Cortex

    PubMed Central

    Yamakawa, Yoshinori; Kanai, Ryota; Matsumura, Michikazu; Naito, Eiichi

    2009-01-01

    Across cultures, social relationships are often thought of, described, and acted out in terms of physical space (e.g. “close friends” “high lord”). Does this cognitive mapping of social concepts arise from shared brain resources for processing social and physical relationships? Using fMRI, we found that the tasks of evaluating social compatibility and of evaluating physical distances engage a common brain substrate in the parietal cortex. The present study shows the possibility of an analytic brain mechanism to process and represent complex networks of social relationships. Given parietal cortex's known role in constructing egocentric maps of physical space, our present findings may help to explain the linguistic, psychological and behavioural links between social and physical space. PMID:19204791

  18. Reconstructing speech from human auditory cortex.

    PubMed

    Pasley, Brian N; David, Stephen V; Mesgarani, Nima; Flinker, Adeen; Shamma, Shihab A; Crone, Nathan E; Knight, Robert T; Chang, Edward F

    2012-01-01

    How the human auditory system extracts perceptually relevant acoustic features of speech is unknown. To address this question, we used intracranial recordings from nonprimary auditory cortex in the human superior temporal gyrus to determine what acoustic information in speech sounds can be reconstructed from population neural activity. We found that slow and intermediate temporal fluctuations, such as those corresponding to syllable rate, were accurately reconstructed using a linear model based on the auditory spectrogram. However, reconstruction of fast temporal fluctuations, such as syllable onsets and offsets, required a nonlinear sound representation based on temporal modulation energy. Reconstruction accuracy was highest within the range of spectro-temporal fluctuations that have been found to be critical for speech intelligibility. The decoded speech representations allowed readout and identification of individual words directly from brain activity during single trial sound presentations. These findings reveal neural encoding mechanisms of speech acoustic parameters in higher order human auditory cortex. PMID:22303281

  19. Reconstructing Speech from Human Auditory Cortex

    PubMed Central

    Pasley, Brian N.; David, Stephen V.; Mesgarani, Nima; Flinker, Adeen; Shamma, Shihab A.; Crone, Nathan E.; Knight, Robert T.; Chang, Edward F.

    2012-01-01

    How the human auditory system extracts perceptually relevant acoustic features of speech is unknown. To address this question, we used intracranial recordings from nonprimary auditory cortex in the human superior temporal gyrus to determine what acoustic information in speech sounds can be reconstructed from population neural activity. We found that slow and intermediate temporal fluctuations, such as those corresponding to syllable rate, were accurately reconstructed using a linear model based on the auditory spectrogram. However, reconstruction of fast temporal fluctuations, such as syllable onsets and offsets, required a nonlinear sound representation based on temporal modulation energy. Reconstruction accuracy was highest within the range of spectro-temporal fluctuations that have been found to be critical for speech intelligibility. The decoded speech representations allowed readout and identification of individual words directly from brain activity during single trial sound presentations. These findings reveal neural encoding mechanisms of speech acoustic parameters in higher order human auditory cortex. PMID:22303281

  20. Speed cells in the medial entorhinal cortex.

    PubMed

    Kropff, Emilio; Carmichael, James E; Moser, May-Britt; Moser, Edvard I

    2015-07-23

    Grid cells in the medial entorhinal cortex have spatial firing fields that repeat periodically in a hexagonal pattern. When animals move, activity is translated between grid cells in accordance with the animal's displacement in the environment. For this translation to occur, grid cells must have continuous access to information about instantaneous running speed. However, a powerful entorhinal speed signal has not been identified. Here we show that running speed is represented in the firing rate of a ubiquitous but functionally dedicated population of entorhinal neurons distinct from other cell populations of the local circuit, such as grid, head-direction and border cells. These 'speed cells' are characterized by a context-invariant positive, linear response to running speed, and share with grid cells a prospective bias of ∼50-80 ms. Our observations point to speed cells as a key component of the dynamic representation of self-location in the medial entorhinal cortex. PMID:26176924

  1. Inhibitory synaptogenesis in mouse somatosensory cortex.

    PubMed

    De Felipe, J; Marco, P; Fairén, A; Jones, E G

    1997-01-01

    It is widely believed that inhibitory synapses are not present or present in only small numbers in the rodent cerebral cortex during the early postnatal period when the cortex is being innervated by thalamocortical fibers. Quantitative electron microscopy was carried out on the posteromedial barrel subfield of mouse somatosensory cortex from postnatal day 4 (P4) when thalamocortical innervation of the barrels is becoming established, through to sexual maturity (>P32), and in adulthood. Both asymmetrical (putatively excitatory) and symmetrical (putatively inhibitory) synapses were present in all layers from P4. The symmetrical synapses were immunoreactive for GABA at all ages. There was a progressive increase in both asymmetrical and symmetrical synapses up to P32, density in all layers increasing 16-fold, with the production of asymmetrical synapses leading and greatly outstripping that of symmetrical. From P32 to P120, the oldest age studied, synaptic numbers declined by 18% to 13 times the P4 level, but this affected predominantly layers II/III, IV and V, and mainly involved asymmetrical synapses. The relative percentage of asymmetrical to symmetrical synapses from P4 to P8 was 57%/43% but at P32 it was 89.5%/10.5% and in adulthood 85.4%/14.6%. These data indicate that inhibitory synaptogenesis in the rodent cortex begins earlier than previously thought, a basis for inhibition being present from the earliest period. Pruning of all synapses occurs well after thalamocortical innervation is established and inhibitory synapses are less affected by the pruning process. PMID:9373018

  2. Separable Prefrontal Cortex Contributions to Free Recall

    PubMed Central

    Long, Nicole M.; Öztekin, Ilke; Badre, David

    2012-01-01

    In everyday life, we often must remember the past in the absence of helpful cues in the environment. In these cases, the brain directs retrieval by relying on internally maintained cues and strategies. Free recall is a widely used behavioral paradigm for studying retrieval with minimal cue support. During free recall, individuals often recall semantically related items consecutively—an effect termed semantic clustering—and previous studies have sought to understand clustering to gain leverage on the basic mechanisms supporting strategic recall. Successful recall and semantic clustering depend on the prefrontal cortex (PFC). However, as a result of methodological limitations, few functional magnetic resonance imaging (fMRI) studies have assessed the neural mechanisms at encoding that support subsequent recall, and none have tested the event-related correlates of recall itself. Thus, it remains open whether one or several frontal control mechanisms operate during encoding and recall. Here, we applied a recently developed method (Öztekin et al., 2010) to assess event-related fMRI signal changes during free recall. During encoding, dorsolateral prefrontal cortex (DLPFC) activation was predictive of subsequent semantic clustering. In contrast, subregions of ventrolateral prefrontal cortex (VLPFC) were predictive of subsequent recall, whether clustered or nonclustered, and were inversely associated with clustering during recall. These results suggest that DLPFC supports relational processes at encoding that are sufficient to produce category clustering effects during recall. Conversely, controlled retrieval mechanisms supported by VLPFC support item-specific search during recall. PMID:20720103

  3. Attentional modulation in human primary olfactory cortex.

    PubMed

    Zelano, Christina; Bensafi, Moustafa; Porter, Jess; Mainland, Joel; Johnson, Brad; Bremner, Elizabeth; Telles, Christina; Khan, Rehan; Sobel, Noam

    2005-01-01

    Central to the concept of attention is the fact that identical stimuli can be processed in different ways. In olfaction, attention may designate the identical flow of air through the nose as either respiration or olfactory exploration. Here we have used functional magnetic resonance imaging (fMRI) to probe this attentional mechanism in primary olfactory cortex (POC). We report a dissociation in POC that revealed attention-dependent and attention-independent subregions. Whereas a temporal subregion comprising temporal piriform cortex (PirT) responded equally across conditions, a frontal subregion comprising frontal piriform cortex (PirF) and the olfactory tubercle responded preferentially to attended sniffs as opposed to unattended sniffs. In addition, a task-specific anticipatory response occurred in the attention-dependent region only. This dissociation was consistent across two experimental designs: one focusing on sniffs of clean air, the other focusing on odor-laden sniffs. Our findings highlight the role of attention at the earliest cortical levels of olfactory processing. PMID:15608635

  4. Parietal Cortex Signals Come Unstuck in Time

    PubMed Central

    Cook, Erik P.; Pack, Christopher C.

    2012-01-01

    Humans and other animals are surprisingly adept at estimating the duration of temporal intervals, even without the use of watches and clocks. This ability is typically studied in the lab by asking observers to indicate their estimate of the time between two external sensory events. The results of such studies confirm that humans can accurately estimate durations on a variety of time scales. Although many brain areas are thought to contribute to the representation of elapsed time, recent neurophysiological studies have linked the parietal cortex in particular to the perception of sub-second time intervals. In this Primer, we describe previous work on parietal cortex and time perception, and we highlight the findings of a study published in this issue of PLOS Biology, in which Schneider and Ghose [1] characterize single-neuron responses during performance of a novel “Temporal Production” task. During temporal production, the observer must track the passage of time without anticipating any external sensory event, and it appears that the parietal cortex may use a unique strategy to support this type of measurement. PMID:23118615

  5. Parietal cortex signals come unstuck in time.

    PubMed

    Cook, Erik P; Pack, Christopher C

    2012-01-01

    Humans and other animals are surprisingly adept at estimating the duration of temporal intervals, even without the use of watches and clocks. This ability is typically studied in the lab by asking observers to indicate their estimate of the time between two external sensory events. The results of such studies confirm that humans can accurately estimate durations on a variety of time scales. Although many brain areas are thought to contribute to the representation of elapsed time, recent neurophysiological studies have linked the parietal cortex in particular to the perception of sub-second time intervals. In this Primer, we describe previous work on parietal cortex and time perception, and we highlight the findings of a study published in this issue of PLOS Biology, in which Schneider and Ghose characterize single-neuron responses during performance of a novel "Temporal Production" task. During temporal production, the observer must track the passage of time without anticipating any external sensory event, and it appears that the parietal cortex may use a unique strategy to support this type of measurement. PMID:23118615

  6. Activity of the motor cortex during scratching.

    PubMed

    Sirota, Mikhail G; Pavlova, Galina A; Beloozerova, Irina N

    2006-02-01

    In awake cats sitting with the head restrained, scratching was evoked using stimulation of the ear. Cats scratched the shoulder area, consistently failing to reach the ear. Kinematics of the hind limb movements and the activity of ankle muscles, however, were similar to those reported earlier in unrestrained cats. The activity of single neurons in the hind limb representation of the motor cortex, including pyramidal tract neurons (PTNs), was examined. During the protraction stage of the scratch response, the activity in 35% of the neurons increased and in 50% decreased compared with rest. During the rhythmic stage, the motor cortex population activity was approximately two times higher compared with rest, because the activity of 53% of neurons increased and that of 33% decreased in this stage. The activity of 61% of neurons was modulated in the scratching rhythm. The average depth of frequency modulation was 12.1 +/- 5.3%, similar to that reported earlier for locomotion. The phases of activity of different neurons were approximately evenly distributed over the scratch cycle. There was no simple correlation between resting receptive field properties and the activity of neurons during the scratch response. We conclude that the motor cortex participates in both the protraction and the rhythmic stages of the scratch response. PMID:16236789

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

    PubMed

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

    2015-01-01

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

  8. Referred pain after painful stimulation of the greater occipital nerve in humans: evidence of convergence of cervical afferences on trigeminal nuclei.

    PubMed

    Piovesan, E J; Kowacs, P A; Tatsui, C E; Lange, M C; Ribas, L C; Werneck, L C

    2001-03-01

    Cranial sensory innervation is supplied mainly by the trigeminal nerves and by the first cervical nerves. Excitatory and inhibitory interactions among those nerve roots may occur in a mechanism called nociceptive convergence, leading to loss of somato-sensory spatial specificity. Three volunteers in an experimental trial had sterile water injected over their greater occipital nerve on one side of the neck. Pain intensity was evaluated 10, 30 and 120 s after the injection. Two of the patients reported intense pain. Trigeminal autonomic features, suggestive of parasympathetic activation, were seen associated with trigeminally distributed pain. These data add to and reinforce previous evidence of convergence of cervical afferents on the trigeminal sensory circuit. PMID:11422092

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

    PubMed Central

    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

  10. fMRI evidence for sensorimotor transformations in human cortex during smooth pursuit eye movements.

    PubMed

    Kimmig, H; Ohlendorf, S; Speck, O; Sprenger, A; Rutschmann, R M; Haller, S; Greenlee, M W

    2008-01-01

    Smooth pursuit eye movements (SP) are driven by moving objects. The pursuit system processes the visual input signals and transforms this information into an oculomotor output signal. Despite the object's movement on the retina and the eyes' movement in the head, we are able to locate the object in space implying coordinate transformations from retinal to head and space coordinates. To test for the visual and oculomotor components of SP and the possible transformation sites, we investigated three experimental conditions: (I) fixation of a stationary target with a second target moving across the retina (visual), (II) pursuit of the moving target with the second target moving in phase (oculomotor), (III) pursuit of the moving target with the second target remaining stationary (visuo-oculomotor). Precise eye movement data were simultaneously measured with the fMRI data. Visual components of activation during SP were located in the motion-sensitive, temporo-parieto-occipital region MT+ and the right posterior parietal cortex (PPC). Motor components comprised more widespread activation in these regions and additional activations in the frontal and supplementary eye fields (FEF, SEF), the cingulate gyrus and precuneus. The combined visuo-oculomotor stimulus revealed additional activation in the putamen. Possible transformation sites were found in MT+ and PPC. The MT+ activation evoked by the motion of a single visual dot was very localized, while the activation of the same single dot motion driving the eye was rather extended across MT+. The eye movement information appeared to be dispersed across the visual map of MT+. This could be interpreted as a transfer of the one-dimensional eye movement information into the two-dimensional visual map. Potentially, the dispersed information could be used to remap MT+ to space coordinates rather than retinal coordinates and to provide the basis for a motor output control. A similar interpretation holds for our results in the PPC region. PMID:18394660

  11. Psychostimulant treatment and the developing cortex in Attention-Deficit/Hyperactivity Disorder

    PubMed Central

    Shaw, Philip; Sharp, Wendy; Morrison, Meaghan; Eckstrand, Kristen; Greenstein, Deanna; Clasen, Liv; Evans, Alan; Rapoport, Judith L.

    2009-01-01

    Objective While there has been considerable concern over possible adverse effects of psychostimulants on brain development, no prospective study has examined this issue. We determined whether psychostimulant drug treatment for Attention-deficit/Hyperactivity Disorder (ADHD) was associated with differences in the development of the cerebral cortex during adolescence. Method Change in cortical thickness was estimated from two neuroanatomic magnetic resonance images on 43 subjects with DSM-IV ADHD (mean age at first scan 12.5 years (SD 2.1); second scan 16.4 (SD2.4). Nineteen subjects not treated with psychostimulants between the scans were compared with an age matched group of 24 subjects who received psychostimulants. Further comparison was made against a template derived from 620 scans on 294 typically developing children. Results Treatment defined ADHD groups differed in rate of change of cortical thickness of the right motor strip, the left middle/inferior frontal gyrus; and the right parieto-occipital region (t(41)=2.8, p=0.009) The group difference was due to more rapid cortical thinning in the group ‘off’ psychostimulants (mean cortical thinning of 0.16mm/year, SD 0.17) compared to the ‘on’ group (thinning of 0.03 mm/year, SD 0.11). Comparison against a typically developing cohort showed the cortical thinning in the ‘off’ psychostimulants group was in excess of age appropriate rates. Treatment groups did not differ however in clinical outcome. Conclusions There was no evidence that psychostimulants were associated with ‘slowing’ of overall growth of the cortical mantle. PMID:18794206

  12. A model of surface depth and orientation predicts BOLD responses in human scene-selective cortex.

    PubMed

    Lescroart, Mark; Gallant, Jack

    2015-01-01

    A network of areas in the human brain-including the Parahippocampal Place Area (PPA), the Occipital Place Area (OPA), and the Retrosplenial Cortex (RSC)-represent visual scenes. However, it is still unclear whether these areas represent high-level features (such as local scene structure or scene category), or low-level features (such as high spatial frequencies and rectilinear corners). To better characterize the representation of visual features in PPA, OPA, and RSC, we define several feature spaces hypothesized to be represented in scene-selective areas, and use them to predict brain activity. The feature spaces we define reflect scene structure (3D orientation of large surfaces), scene expanse (distance from visible surfaces to the virtual camera), and local spatial frequency (Gabor wavelet transformations) of each rendered scene. We fit each feature space to BOLD fMRI data recorded while human subjects viewed movies of a virtual world rendered using 3D graphics software. The graphics software allows us to quantify scene structure and expanse with continuous parameters instead of categorical labels such as "open" or "closed". We fit models for all feature spaces using L2-regularized regression, and evaluate each model based on how much response variance it predicts in a withheld data set. The scene structure model explains more response variance in our data than the scene expanse and local spatial frequency models. A hybrid model that combines surface orientation and distance from the virtual camera explains still more variance. These results are consistent whether subjects attend to the size of each scene or to the number of objects in each scene. Together, these results suggest that PPA, OPA, and RSC represent conjunctions of the depth and orientation of walls, ceilings, and other large objects in scenes. Meeting abstract presented at VSS 2015. PMID:26326261

  13. Flexible Reference Frames for Grasp Planning in Human Parietofrontal Cortex1,2,3

    PubMed Central

    Leoné, Frank T. M.; Monaco, Simona; Henriques, Denise Y. P.; Toni, Ivan

    2015-01-01

    Abstract Reaching to a location in space is supported by a cortical network that operates in a variety of reference frames. Computational models and recent fMRI evidence suggest that this diversity originates from neuronal populations dynamically shifting between reference frames as a function of task demands and sensory modality. In this human fMRI study, we extend this framework to nonmanipulative grasping movements, an action that depends on multiple properties of a target, not only its spatial location. By presenting targets visually or somaesthetically, and by manipulating gaze direction, we investigate how information about a target is encoded in gaze- and body-centered reference frames in dorsomedial and dorsolateral grasping-related circuits. Data were analyzed using a novel multivariate approach that combines classification and cross-classification measures to explicitly aggregate evidence in favor of and against the presence of gaze- and body-centered reference frames. We used this approach to determine whether reference frames are differentially recruited depending on the availability of sensory information, and where in the cortical networks there is common coding across modalities. Only in the left anterior intraparietal sulcus (aIPS) was coding of the grasping target modality dependent: predominantly gaze-centered for visual targets and body-centered for somaesthetic targets. Left superior parieto-occipital cortex consistently coded targets for grasping in a gaze-centered reference frame. Left anterior precuneus and premotor areas operated in a modality-independent, body-centered frame. These findings reveal how dorsolateral grasping area aIPS could play a role in the transition between modality-independent gaze-centered spatial maps and body-centered motor areas. PMID:26464989

  14. The Role of Parieto-Occipital Junction in the Interaction between Dorsal and Ventral Streams in Disparity-Defined Near and Far Space Processing.

    PubMed

    Wang, Aijun; Li, You; Zhang, Ming; Chen, Qi

    2016-01-01

    Neuropsychological and functional MRI data suggest that two functionally and anatomically dissociable streams of visual processing exist: a ventral perception-related stream and a dorsal action-related stream. However, relatively little is known about how the two streams interact in the intact brain during the production of adaptive behavior. Using functional MRI and a virtual three-dimensional paradigm, we aimed at examining whether the parieto-occipital junction (POJ) acts as an interface for the integration and processing of information between the dorsal and ventral streams in the near and far space processing. Virtual reality three-dimensional near and far space was defined by manipulating binocular disparity, with -68.76 arcmin crossed disparity for near space and +68.76 arcmin uncrossed disparity for near space. Our results showed that the POJ and bilateral superior occipital gyrus (SOG) showed relative increased activity when responded to targets presented in the near space than in the far space, which was independent of the retinotopic and perceived sizes of target. Furthermore, the POJ showed the enhanced functional connectivity with both the dorsal and ventral streams during the far space processing irrespective of target sizes, supporting that the POJ acts as an interface between the dorsal and ventral streams in disparity-defined near and far space processing. In contrast, the bilateral SOG showed the enhanced functional connectivity only with the ventral stream if retinotopic sizes of targets in the near and far spaces were matched, which suggested there was a functional dissociation between the POJ and bilateral SOG. PMID:26999674

  15. [A Study of the relationship between craniofacial morphology and the occlusion in lacteal dentition: occipital remodeling specificities and basicranial individual features that play an occlusal key role].

    PubMed

    Deshayes, Marie-Josèphe; Deshayes, Julie

    2013-03-01

    Before performing any procedure or initiating early intervention on children in lacteal dentition, it is crucial to closely investigate a few key elements of the cranial base of the child. A first step of diagnostics is needed - the classification of the dysharmony ie its squelettal and/or functional element - before we prescribe a major orthopedic treatment or just stop dysfunctions using simple functional appliances. To confront these constraints of diagnostic, a set of 243 children in the lacteal dentition was examined. Our clinical expertise made it possible to select cephalometric measurements that would be supposedly linked with the type of skeletal dysharmony (based on cranial and facial osseous landmarks located on the profile-view of a digital tele-X-ray). The occlusal classification takes into account occlusal criteria and the design of the masticatory function. Statistical analysis (namely linear discriminant analysis of cephalometric variables) indicates that in lacteal dentition, some cranial architectural features have preferred links with specific occlusions. We noticed that the amplitude of basicranial "flexure" (hence the sphenoidal angle) is influenced by the occipital remodeling: the ontogenic process of flexion of the base and the amplitude of closure of the sphenoid angle are under controlled by the remodeling of the occipital bone in three main modalities. Correlations exist between these groups and the facial equilibrium, like a forward or backward position of the chin. The important clinical deduction is that the masticatory function in lacteal dentition is organized by architectural constraints that arise from the remodeling of the cranial base; the squelettal effect of dysfunctions is certainly specific to each type of dysfunction, nonetheless it also depends on the architectural uniqueness of the cranial base. PMID:23531294

  16. The Role of Parieto-Occipital Junction in the Interaction between Dorsal and Ventral Streams in Disparity-Defined Near and Far Space Processing

    PubMed Central

    Zhang, Ming; Chen, Qi

    2016-01-01

    Neuropsychological and functional MRI data suggest that two functionally and anatomically dissociable streams of visual processing exist: a ventral perception-related stream and a dorsal action-related stream. However, relatively little is known about how the two streams interact in the intact brain during the production of adaptive behavior. Using functional MRI and a virtual three-dimensional paradigm, we aimed at examining whether the parieto-occipital junction (POJ) acts as an interface for the integration and processing of information between the dorsal and ventral streams in the near and far space processing. Virtual reality three-dimensional near and far space was defined by manipulating binocular disparity, with -68.76 arcmin crossed disparity for near space and +68.76 arcmin uncrossed disparity for near space. Our results showed that the POJ and bilateral superior occipital gyrus (SOG) showed relative increased activity when responded to targets presented in the near space than in the far space, which was independent of the retinotopic and perceived sizes of target. Furthermore, the POJ showed the enhanced functional connectivity with both the dorsal and ventral streams during the far space processing irrespective of target sizes, supporting that the POJ acts as an interface between the dorsal and ventral streams in disparity-defined near and far space processing. In contrast, the bilateral SOG showed the enhanced functional connectivity only with the ventral stream if retinotopic sizes of targets in the near and far spaces were matched, which suggested there was a functional dissociation between the POJ and bilateral SOG. PMID:26999674

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

    PubMed

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

    2015-01-01

    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

  18. Patterns of neural activity in the human ventral premotor cortex reflect a whole-body multisensory percept

    PubMed Central

    Gentile, Giovanni; Björnsdotter, Malin; Petkova, Valeria I.; Abdulkarim, Zakaryah; Ehrsson, H. Henrik

    2015-01-01

    Previous research has shown that the integration of multisensory signals from the body in fronto-parietal association areas underlies the perception of a body part as belonging to one's physical self. What are the neural mechanisms that enable the perception of one's entire body as a unified entity? In one behavioral and one fMRI multivoxel pattern analysis experiment, we used a full-body illusion to investigate how congruent visuo-tactile signals from a single body part facilitate the emergence of the sense of ownership of the entire body. To elicit this illusion, participants viewed the body of a mannequin from the first-person perspective via head-mounted displays while synchronous touches were applied to the hand, abdomen, or leg of the bodies of the participant and the mannequin; asynchronous visuo-tactile stimuli served as controls. The psychometric data indicated that the participants perceived ownership of the entire artificial body regardless of the body segment that received the synchronous visuo-tactile stimuli. Based on multivoxel pattern analysis, we found that the neural responses in the left ventral premotor cortex displayed illusion-specific activity patterns that generalized across all tested pairs of body parts. Crucially, a tripartite generalization analysis revealed the whole-body specificity of these premotor activity patterns. Finally, we also identified multivoxel patterns in the premotor, intraparietal, and lateral occipital cortices and in the putamen that reflected multisensory responses specific to individual body parts. Based on these results, we propose that the dynamic formation of a whole-body percept may be mediated by neuronal populations in the ventral premotor cortex that contain visuo-tactile receptive fields encompassing multiple body segments. PMID:25583608

  19. Reduced visual cortex gray matter volume and thickness in young adults who witnessed domestic violence during childhood.

    PubMed

    Tomoda, Akemi; Polcari, Ann; Anderson, Carl M; Teicher, Martin H

    2012-01-01

    Exposure to interparental violence is associated with negative outcomes, such as depression, post-traumatic stress disorder and reduced cognitive abilities. However, little is known about the potential effects of witnessing domestic violence during childhood on gray matter volume (GMV) or cortical thickness. High-resolution 3.0 T volumetric scans (Siemens Trio Scanner) were obtained on 52 subjects (18-25 years) including 22 (6 males/16 females) with a history of visually witnessing episodes of domestic violence, and 30 (8 males/22 females) unexposed control subjects, with neither a current nor past DSM-IV Axis I or II disorder. Potential confounding effects of age, gender, level of parental verbal aggression, parental education, financial stress, full scale IQ, and total GMV, or average thickness were modeled using voxel based morphometry and FreeSurfer. Witnessing domestic violence subjects had a 6.1% GMV reduction in the right lingual gyrus (BA18) (P = 0.029, False Discovery Rate corrected peak level). Thickness in this region was also reduced, as was thickness in V2 bilaterally and left occipital pole. Theses regions were maximally sensitive to exposure to witnessing domestic violence between 11-13 years of age. Regional reductions in GMV and thickness were observed in both susceptible and resilient witnessing domestic violence subjects. Results in subjects witnessing domestic violence were similar to previously reported results in subjects with childhood sexual abuse, as the primary region affected was visual cortex. Brain regions that process and convey the adverse sensory input of the abuse may be specifically modified by this experience, particularly in subjects exposed to a single type of maltreatment. Exposure to multiple types of maltreatment is more commonly associated with morphological alterations in corticolimbic regions. These findings fit with preclinical studies showing that visual cortex is a highly plastic structure. PMID:23300699

  20. Patterns of neural activity in the human ventral premotor cortex reflect a whole-body multisensory percept.

    PubMed

    Gentile, Giovanni; Björnsdotter, Malin; Petkova, Valeria I; Abdulkarim, Zakaryah; Ehrsson, H Henrik

    2015-04-01

    Previous research has shown that the integration of multisensory signals from the body in fronto-parietal association areas underlies the perception of a body part as belonging to one's physical self. What are the neural mechanisms that enable the perception of one's entire body as a unified entity? In one behavioral and one fMRI multivoxel pattern analysis experiment, we used a full-body illusion to investigate how congruent visuo-tactile signals from a single body part facilitate the emergence of the sense of ownership of the entire body. To elicit this illusion, participants viewed the body of a mannequin from the first-person perspective via head-mounted displays while synchronous touches were applied to the hand, abdomen, or leg of the bodies of the participant and the mannequin; asynchronous visuo-tactile stimuli served as controls. The psychometric data indicated that the participants perceived ownership of the entire artificial body regardless of the body segment that received the synchronous visuo-tactile stimuli. Based on multivoxel pattern analysis, we found that the neural responses in the left ventral premotor cortex displayed illusion-specific activity patterns that generalized across all tested pairs of body parts. Crucially, a tripartite generalization analysis revealed the whole-body specificity of these premotor activity patterns. Finally, we also identified multivoxel patterns in the premotor, intraparietal, and lateral occipital cortices and in the putamen that reflected multisensory responses specific to individual body parts. Based on these results, we propose that the dynamic formation of a whole-body percept may be mediated by neuronal populations in the ventral premotor cortex that contain visuo-tactile receptive fields encompassing multiple body segments. PMID:25583608

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

    PubMed

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

    2014-11-01

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

  2. Lack of effect of histological lesions on the phenytoin and phenobarbital concentrations in the brain cortex of epileptic patients.

    PubMed

    Schnabel, R; Rambeck, B; May, T W; Jürgens, U; Lahl, R; Villagrán, R

    1995-11-01

    Postmortem concentrations of phenytoin (PHT) and phenobarbital (PB) were determined in 24 specimens