reviews - Center for Complex Systems and Brain Sciences
... present at the locations visited by observers while freeviewing images50,51. For instance, Zetzsche et al.50,52 showed using an eye-tracking device how the eyes preferentially fixate regions with multiple superimposed orientations such as corners, and derived nonlinear operators that specifically de ...
... present at the locations visited by observers while freeviewing images50,51. For instance, Zetzsche et al.50,52 showed using an eye-tracking device how the eyes preferentially fixate regions with multiple superimposed orientations such as corners, and derived nonlinear operators that specifically de ...
the clinical role of evoked potentials
... In theory almost any sensory modality may be tested, although in routine clinical practice pattern reversal visual evoked potentials (VEPs), short latency somatosensory evoked potentials (SSEPs), and brainstem auditory evoked potentials (BSAEPs) are tested most frequently. Longer latency responses t ...
... In theory almost any sensory modality may be tested, although in routine clinical practice pattern reversal visual evoked potentials (VEPs), short latency somatosensory evoked potentials (SSEPs), and brainstem auditory evoked potentials (BSAEPs) are tested most frequently. Longer latency responses t ...
Topographic maps in human frontal and parietal cortex
... Retinotopic mapping of functional magnetic resonance (fMRI) responses evoked by visual stimuli has resulted in the identification of many areas in human visual cortex and a description of the organization of the visual field representation in each of these areas. These methods have recently been emp ...
... Retinotopic mapping of functional magnetic resonance (fMRI) responses evoked by visual stimuli has resulted in the identification of many areas in human visual cortex and a description of the organization of the visual field representation in each of these areas. These methods have recently been emp ...
PDF
... limited conditions would, therefore, be about 5min for a stage-66 animal and 30min for a oneyear-old animal. Precautions to minimize visual experience were also taken during the preparation for terminal electrophysiological experiments. The animals were transported from the animal accommodation to t ...
... limited conditions would, therefore, be about 5min for a stage-66 animal and 30min for a oneyear-old animal. Precautions to minimize visual experience were also taken during the preparation for terminal electrophysiological experiments. The animals were transported from the animal accommodation to t ...
Williams Syndrome Neuronal Size and Neuronal-Packing Density in Primary Visual Cortex
... distribution of cell size differences between hemispheres for WMS-affected and control brains separately. We set ! = .001 for rejection of the null hypothesis to compensate for the high sensitivity of this test. We examined each layer collapsed over both hemispheres between control and WMS-affected ...
... distribution of cell size differences between hemispheres for WMS-affected and control brains separately. We set ! = .001 for rejection of the null hypothesis to compensate for the high sensitivity of this test. We examined each layer collapsed over both hemispheres between control and WMS-affected ...
Seeing faces and objects with the “mind`s eye”
... specific picture of Marilyn Monroe and shortly after generate a mental image of that picture (STM). We also tested the effect of focal attention during visual imagery. Numerous fMRI studies have shown that selective attention to particular attributes of visual stimuli, such as color or motion, enhan ...
... specific picture of Marilyn Monroe and shortly after generate a mental image of that picture (STM). We also tested the effect of focal attention during visual imagery. Numerous fMRI studies have shown that selective attention to particular attributes of visual stimuli, such as color or motion, enhan ...
Visual adaptation: Neural, psychological and computational aspects
... of processing adapt and how plasticity occurring early in the processing stream impacts downstream areas. In macaque IT cortex, for example, neuronal adaptation has been reported to show greater selectivity than the response of the corresponding neuron, suggesting that adaptation is occurring at or ...
... of processing adapt and how plasticity occurring early in the processing stream impacts downstream areas. In macaque IT cortex, for example, neuronal adaptation has been reported to show greater selectivity than the response of the corresponding neuron, suggesting that adaptation is occurring at or ...
Attention maps in the brain - Site BU
... isual perception often feels effortless; however, in many complex situations, there is far more information reaching our eyes than our cognitive systems can act on at one time. Although the retina performs massively parallel processing, visual cognition operates on no more than a few items at once. ...
... isual perception often feels effortless; however, in many complex situations, there is far more information reaching our eyes than our cognitive systems can act on at one time. Although the retina performs massively parallel processing, visual cognition operates on no more than a few items at once. ...
PDF preprint - The Computational Neurobiology Laboratory
... therefore that the lateral connections modulate rather than drive V1 activity. It can be shown (Wiener, 1994; Cowan, 1997; Bressloff et al., 2000) that the weighting function defined in equation (1.2) has a well defined symmetry: it is invariant with respect to certain operations in the plane of V1–tra ...
... therefore that the lateral connections modulate rather than drive V1 activity. It can be shown (Wiener, 1994; Cowan, 1997; Bressloff et al., 2000) that the weighting function defined in equation (1.2) has a well defined symmetry: it is invariant with respect to certain operations in the plane of V1–tra ...
Some Analogies Between Visual Cortical and Genetic Maps
... red and green receptor proteins are located adjacent to each other on the X chromosome and have a 96% sequence homology.32 Many individuals have up to three slightly different versions of the gene for the green receptor protein. It is not clear how these multiple green receptor genes contribute to p ...
... red and green receptor proteins are located adjacent to each other on the X chromosome and have a 96% sequence homology.32 Many individuals have up to three slightly different versions of the gene for the green receptor protein. It is not clear how these multiple green receptor genes contribute to p ...
Decoding visual consciousness from human
... study. Experiences can vary along several dimensions (shades of brightness, orientations, textures and so on) and hierarchical levels (simple features, intermediate shapes and complex objects). (b) Each particular class of experiences is presumably encoded in a specific core NCC. For intensities, su ...
... study. Experiences can vary along several dimensions (shades of brightness, orientations, textures and so on) and hierarchical levels (simple features, intermediate shapes and complex objects). (b) Each particular class of experiences is presumably encoded in a specific core NCC. For intensities, su ...
Relative timing: from behaviour to neurons
... Timing is central for myriad aspects of behaviour. All forms of life generate behaviours that play out according to precise sequences in time, spanning multiple temporal scales. Complex behaviours such as locomotion or grasping and manipulation require coordinated temporal cascades of muscular activ ...
... Timing is central for myriad aspects of behaviour. All forms of life generate behaviours that play out according to precise sequences in time, spanning multiple temporal scales. Complex behaviours such as locomotion or grasping and manipulation require coordinated temporal cascades of muscular activ ...
Visual Fields
... Visual fields are an important test of the visual system. They allow us to determine the health of the ocular system including the eye, visual pathways and visual cortex. We will explore visual fields as an important tool for eye care practitioners in assessing the health of the visual system. We wi ...
... Visual fields are an important test of the visual system. They allow us to determine the health of the ocular system including the eye, visual pathways and visual cortex. We will explore visual fields as an important tool for eye care practitioners in assessing the health of the visual system. We wi ...
Computational modeling of responses in human visual
... resonance imaging (fMRI). These fields use a diverse array of experimental, statistical and computational methods to analyze and interpret fMRI responses, and this diversity reflects the questions of interest to each field. The approach in vision science differs substantially from that taken in most ...
... resonance imaging (fMRI). These fields use a diverse array of experimental, statistical and computational methods to analyze and interpret fMRI responses, and this diversity reflects the questions of interest to each field. The approach in vision science differs substantially from that taken in most ...
Neural coding of behavioral relevance in parietal cortex
... same direction as the attended stimulus. Among extrastriate visual areas, feature-based attention was particularly strong in MT [41], a similar result to that of experiments described above in monkey MT [18]. If attention to a non-spatial attribute (such as direction) can ‘spread’ to an ignored stim ...
... same direction as the attended stimulus. Among extrastriate visual areas, feature-based attention was particularly strong in MT [41], a similar result to that of experiments described above in monkey MT [18]. If attention to a non-spatial attribute (such as direction) can ‘spread’ to an ignored stim ...
Human brain spots emotion in non humanoid
... expression at a latency of 90 ms, and differentiating monkey identity about 70 ms later (Sugase et al., 1999). These delays meet P1 and N170 visual components latencies in human EEG studies, with the P1 wave being modulated by emotion, and the N170 wave being mainly modulated by facial configuration ...
... expression at a latency of 90 ms, and differentiating monkey identity about 70 ms later (Sugase et al., 1999). These delays meet P1 and N170 visual components latencies in human EEG studies, with the P1 wave being modulated by emotion, and the N170 wave being mainly modulated by facial configuration ...
Visual Properties of Neurons in a Polysensory Area in Superior
... Most STP units, 70% of the 199 tested, had little or no preference for stimulus size, shape, orientation, or contrast. These nonselective units would respond similarly to spots and slits of light, to shadows, to slides and photographs of complex objects, and to three-dimensional objects. Many of the ...
... Most STP units, 70% of the 199 tested, had little or no preference for stimulus size, shape, orientation, or contrast. These nonselective units would respond similarly to spots and slits of light, to shadows, to slides and photographs of complex objects, and to three-dimensional objects. Many of the ...
T2 - Center for Neural Basis of Cognition
... Remapping occurs at early stages of the visual hierarchy. Corollary discharge has an impact far back into the system. Remapping implies widespread connectivity in which many neurons have rapid access to information well beyond the classical receptive field. Vision is an active process of building re ...
... Remapping occurs at early stages of the visual hierarchy. Corollary discharge has an impact far back into the system. Remapping implies widespread connectivity in which many neurons have rapid access to information well beyond the classical receptive field. Vision is an active process of building re ...
Features of Neuronal Synchrony in Mouse Visual Cortex
... been hypothesized to play a role in defining cell assemblies representing particular constellations of stimulus features. In many systems and species, synchronization is accompanied by an oscillatory response modulation at frequencies in the ␥-band. The cellular mechanisms underlying these phenomena ...
... been hypothesized to play a role in defining cell assemblies representing particular constellations of stimulus features. In many systems and species, synchronization is accompanied by an oscillatory response modulation at frequencies in the ␥-band. The cellular mechanisms underlying these phenomena ...
The role of early visual cortex in visual integration: a neural model of
... recent neurophysiological experiments have demonstrated that the long-latency responses of V1 neurons reflects top-down attention (Motter, 1993; Hupe et al., 1998; Roelfsema et al., 1998; Ito & Gilbert, 1999) or other higher order perceptual context, such as ‘figure-ground’ (Lamme, 1995; Zipser et al. ...
... recent neurophysiological experiments have demonstrated that the long-latency responses of V1 neurons reflects top-down attention (Motter, 1993; Hupe et al., 1998; Roelfsema et al., 1998; Ito & Gilbert, 1999) or other higher order perceptual context, such as ‘figure-ground’ (Lamme, 1995; Zipser et al. ...
Specialization within the ventral stream: The case for the visual word
... Unfortunately, in their critique of the visual word form area, P&D adopt neither of those stances. Their argument relies almost exclusively on the overlap of data from different groups of subjects scanned with PET. However, such data are typically generated with a spatial smoothness of 15 mm in PET ...
... Unfortunately, in their critique of the visual word form area, P&D adopt neither of those stances. Their argument relies almost exclusively on the overlap of data from different groups of subjects scanned with PET. However, such data are typically generated with a spatial smoothness of 15 mm in PET ...
Learning Strengthens the Response of Primary Visual Cortex to
... may have shifted toward the trained stimulus. The observed changes in V1 could be produced locally or could result from feedback from higher cortical areas. Studies of V1 with single-unit recording report different neural effects of learning than those observed here [14–16]. None of the studies repo ...
... may have shifted toward the trained stimulus. The observed changes in V1 could be produced locally or could result from feedback from higher cortical areas. Studies of V1 with single-unit recording report different neural effects of learning than those observed here [14–16]. None of the studies repo ...
Spikes not slots: noise in neural populations limits
... (LPFC); similar results were found in frontal eye field (FEF) and lateral intraparietal (LIP) areas. Note that significant differences between two and three items were observed only in the late phase of the delay in the LPFC; however, this was not a consistent observation across brain areas. (C) An ...
... (LPFC); similar results were found in frontal eye field (FEF) and lateral intraparietal (LIP) areas. Note that significant differences between two and three items were observed only in the late phase of the delay in the LPFC; however, this was not a consistent observation across brain areas. (C) An ...
A multi-level account of selective attention
... all that was retained from the unattended auditory stream. Not long after Broadbent’s seminal book, Moray (1959) demonstrated that selection was not always implemented by an early filtering mechanism, as he noted that about one-third of subjects detected their own name when it was inserted in the un ...
... all that was retained from the unattended auditory stream. Not long after Broadbent’s seminal book, Moray (1959) demonstrated that selection was not always implemented by an early filtering mechanism, as he noted that about one-third of subjects detected their own name when it was inserted in the un ...
Lateral Geniculate nucleus
... Primary Visual Cortex The primary visual cortex (V1) has a representation of the contralateral visual hemifield. The foveal region is mapped in its most posterior part, whereas the more peripheral regions are mapped in progressively more anterior parts. The upper visual field is mapped below the cal ...
... Primary Visual Cortex The primary visual cortex (V1) has a representation of the contralateral visual hemifield. The foveal region is mapped in its most posterior part, whereas the more peripheral regions are mapped in progressively more anterior parts. The upper visual field is mapped below the cal ...
P200
In neuroscience, the visual P200 or P2 is a waveform component or feature of the event-related potential (ERP) measured at the human scalp. Like other potential changes measurable from the scalp, this effect is believed to reflect the post-synaptic activity of a specific neural process. The P2 component, also known as the P200, is so named because it is a positive going electrical potential that peaks at about 200 milliseconds (varying between about 150 and 275 ms) after the onset of some external stimulus . The distribution of this component in the brain, as measured by electrodes placed across the scalp, is located around the centro-frontal and the parieto-occipital region. It is generally found to be maximal around the vertex (frontal region) of the scalp, however there have been some topographical differences noted in ERP studies of the P2 in different experimental conditions.Research on the visual P2 is at an early stage compared to other more established ERP components and there is much that we still do not know about it. Part of the difficulty of clearly characterizing this component is that it appears to be modulated by a large and diverse number of cognitive tasks. Functionally, there seems to be partial agreement amongst researchers in the field of cognitive neuroscience that the P2 represents some aspect of higher-order perceptual processing, modulated by attention. It is known that the P2 is typically elicited as part of the normal response to visual stimuli and has been studied in relation to visual search and attention, language context information, and memory and repetition effects. The amplitude of the peak of the waveform may be modulated by many different aspects of visual stimuli, which allow it to be used for studies of visual cognition and disease. In general, the P2 may be a part of cognitive matching system that compares sensory inputs with stored memory.