Human Visual Cortex
Mostrando 1-12 de 106 artigos, teses e dissertações.
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1. Mapeamento do cortex visual humano atraves de uma abordagem multimodal integrando eletroencefalografia e espectroscopia optica na região do infravermelho proximo / Mapping of the human visual cortex by a multimodal approach integrating electroencephalography and near infrared spectroscopy
A ativação cerebral envolve um complexo arranjo de processos neuronais, metabólicos e vasculares, que se estende do nível molecular e celular ao nível de extensas zonas corticais. O processo de disparo neuronal requer a restauração de gradientes iônicos e a reciclagem de neurotransmissores, o que implica em um custo energético suprido na forma de tr
Publicado em: 2009
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2. Uma modelagem matemático-computacional do sistema biológico de percepção de movimento e velocidade
Everything that we see is mentally built by the human brains visual system, from the stimuli received by the retinas: the perception of color, shape, depth and motion, the objects and the complete visual scenes. Researches on artificial intelligence, especially applied to robotics, look for emulating this biological function, in order to enable artificial sy
Publicado em: 2006
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3. Interhemispheric connections between primary visual areas: beyond the midline rule
In the last five years, a number of detailed anatomical, electrophysiological, optical imaging and simulation studies performed in a variety of non-human species have revealed that the functional organization of callosal connections between primary visual areas is more elaborate than previously thought. Callosal cell bodies and terminals are clustered in col
Brazilian Journal of Medical and Biological Research. Publicado em: 2002-12
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4. Mechanisms of migraine aura revealed by functional MRI in human visual cortex
Cortical spreading depression (CSD) has been suggested to underlie migraine visual aura. However, it has been challenging to test this hypothesis in human cerebral cortex. Using high-field functional MRI with near-continuous recording during visual aura in three subjects, we observed blood oxygenation level-dependent (BOLD) signal changes that demonstra
The National Academy of Sciences.
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5. Activation of human primary visual cortex during visual recall: a magnetic resonance imaging study.
The degree to which the process involved in visual perception and visual imagery share a common neuroanatomical substrate is unclear. Physiological evidence for localization of visual imagery early in the visual pathways would have important bearing on current theories of visual processing. A magnetic resonance imaging technique sensitive to regional changes
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6. Local and global attention are mapped retinotopically in human occipital cortex
Clinical evidence suggests that control mechanisms for local and global attention are lateralized in the temporal–parietal cortex. However, in the human occipital (visual) cortex, the evidence for lateralized local/global attention is controversial. To clarify this matter, we used functional MRI to map activity in the human occipital cortex, during lo
The National Academy of Sciences.
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7. Dissociation of object and spatial visual processing pathways in human extrastriate cortex.
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 c
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8. Responses of human visual cortex to uniform surfaces
Surface perception is fundamental to human vision, yet most studies of visual cortex have focused on the processing of borders. We therefore investigated the responses of human visual cortex to parametric changes in the luminance of uniform surfaces by using functional MRI. Early visual areas V1 and V2/V3 showed strong and reliable increases in signal for bo
National Academy of Sciences.
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9. Molecular differences among neurons reveal an organization of human visual cortex.
Monoclonal antibody Cat-301 recognizes a cell-surface proteoglycan on subsets of neurons in several areas of the cat and macaque monkey central nervous system. In striate and extrastriate visual cortex of the macaque, the distribution of Cat-301-positive neurons demonstrates features of cellular organization that correlate with previously described functiona
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10. Mechanisms underlying rapid experience-dependent plasticity in the human visual cortex
Visual deprivation induces a rapid increase in visual cortex excitability that may result in better consolidation of spatial memory in animals and in lower visual recognition thresholds in humans. γ-Aminobutyric acid (GABA)ergic, N-methyl-d-aspartate (NMDA), and cholinergic receptors are thought to be involved in visual cortex plasticity in animal stu
The National Academy of Sciences.
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11. The representation of the ipsilateral visual field in human cerebral cortex
Previous studies of cortical retinotopy focused on influences from the contralateral visual field, because ascending inputs to cortex are known to be crossed. Here, functional magnetic resonance imaging was used to demonstrate and analyze an ipsilateral representation in human visual cortex. Moving stimuli, in a range of ipsilateral visual field locatio
The National Academy of Sciences.
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12. Mapping striate and extrastriate visual areas in human cerebral cortex.
Functional magnetic resonance imaging (fMRI) was used to identify and map the representation of the visual field in seven areas of human cerebral cortex and to identify at least two additional visually responsive regions. The cortical locations of neurons responding to stimulation along the vertical or horizontal visual field meridia were charted on three-di