Models and Measurements of Functional Maps in V1
... from single-unit studies that individual neurons are preferentially sensitive to a small set of stimulus features and that neuronal sensitivity to these features varies across the cortical sheet within a visual area (Hubel and Wiesel 1962). Over the last 20 years, optical imaging has allowed the act ...
... from single-unit studies that individual neurons are preferentially sensitive to a small set of stimulus features and that neuronal sensitivity to these features varies across the cortical sheet within a visual area (Hubel and Wiesel 1962). Over the last 20 years, optical imaging has allowed the act ...
Retinotopic Organization and Functional Subdivisions of the Human
... thereby evoking waves of activation in neurons through whose receptive fields they passed. Each region of the stimulated visual field was exposed to a flickering checkerboard pattern during one-half of the stimulus period and the neutral gray background during the other half. The stimulus waveform w ...
... thereby evoking waves of activation in neurons through whose receptive fields they passed. Each region of the stimulated visual field was exposed to a flickering checkerboard pattern during one-half of the stimulus period and the neutral gray background during the other half. The stimulus waveform w ...
The Optic Tectum of Birds - Department of Psychology
... Figure 3. Connectivity of the isthmal nuclei with the tectum. (A) shows a coronal section through the tectum showing typical injections of fluorescent biotinylated dextran amines (BDA). A retrogradely labelled cell and anterogradely labelled terminals from the red injection can be seen in parvocellu ...
... Figure 3. Connectivity of the isthmal nuclei with the tectum. (A) shows a coronal section through the tectum showing typical injections of fluorescent biotinylated dextran amines (BDA). A retrogradely labelled cell and anterogradely labelled terminals from the red injection can be seen in parvocellu ...
Chapter 4 monkey
... underlies our ability to integrate past memories and present experiences. In this study we investigated how learning influences the process of decision making by recording the activity of single neurons in the frontal eye fields (FEF). The responses of FEF neurons to visual stimuli are modulated by ...
... underlies our ability to integrate past memories and present experiences. In this study we investigated how learning influences the process of decision making by recording the activity of single neurons in the frontal eye fields (FEF). The responses of FEF neurons to visual stimuli are modulated by ...
The response of cat visual cortex to flicker stimuli of variable frequency
... et al., 1989; for review see Singer & Gray, 1995). This suggests the possibility that the synchronous responses evoked by simultaneously appearing stimuli may also be used for binding. Psychophysical studies actually indicate that visual stimuli get bound perceptually if they are coincident in time ...
... et al., 1989; for review see Singer & Gray, 1995). This suggests the possibility that the synchronous responses evoked by simultaneously appearing stimuli may also be used for binding. Psychophysical studies actually indicate that visual stimuli get bound perceptually if they are coincident in time ...
Visual Processing in the Primate Brain
... Vision begins at the eye with light passing through the cornea (refracts light), pupil (controls how much light enters the eye), and the lens (adjustably focuses light) onto the retina at the back of the eye. At the retina, photoreceptors convert the photons to electrochemical signals that are relay ...
... Vision begins at the eye with light passing through the cornea (refracts light), pupil (controls how much light enters the eye), and the lens (adjustably focuses light) onto the retina at the back of the eye. At the retina, photoreceptors convert the photons to electrochemical signals that are relay ...
Neuropsychologia, 47, 1621-6
... projector itself. A custom-made start button, fastened to the table, was used to record the initiation of the pointing response and to trigger the closure of liquid-crystal display goggles (PLATO, Translucent Technologies) that were worn by the participants. The PLATO goggles were to control stimulu ...
... projector itself. A custom-made start button, fastened to the table, was used to record the initiation of the pointing response and to trigger the closure of liquid-crystal display goggles (PLATO, Translucent Technologies) that were worn by the participants. The PLATO goggles were to control stimulu ...
Linking Neural Activity to Visual Perception: Separating Sensory and
... We can use the specialization of visual cortical neurons to begin understanding how they support visual perception. This is accomplished by comparing the activity of a neuron to the responses of an observer performing a perceptual task [1]. Neurons from the Middle Temporal area of visual cortex (MT ...
... We can use the specialization of visual cortical neurons to begin understanding how they support visual perception. This is accomplished by comparing the activity of a neuron to the responses of an observer performing a perceptual task [1]. Neurons from the Middle Temporal area of visual cortex (MT ...
Normalization in human somatosensory cortex
... level (“target ⫹ mask”). In addition, we included separate “maskonly” and “target-only” trials (at 50% of maximum vibration level) for estimating the weights on the forward model (see below). All 12 possible stimuli (5 amplitude levels with mask absent, 5 amplitude conditions with target ⫹ mask, tar ...
... level (“target ⫹ mask”). In addition, we included separate “maskonly” and “target-only” trials (at 50% of maximum vibration level) for estimating the weights on the forward model (see below). All 12 possible stimuli (5 amplitude levels with mask absent, 5 amplitude conditions with target ⫹ mask, tar ...
Action Preparation Shapes Processing in Early Visual Cortex
... A posterior volume was scanned (indicated in red), here depicted on a single subject anatomy (right). The partial volume was started with an instructional color cue, indicatchosen to encompass both the early visual areas and the anterior parietal areas. Subjects were able to see the grasping/pointin ...
... A posterior volume was scanned (indicated in red), here depicted on a single subject anatomy (right). The partial volume was started with an instructional color cue, indicatchosen to encompass both the early visual areas and the anterior parietal areas. Subjects were able to see the grasping/pointin ...
Inferior Parietal Lobule Function in Spatial Perception and
... Progress has been more difficult in gaining an understanding of the somatosensory functions of this area and the possible role the IPL may play in the integration of somatosensory and visual information. It is becoming clear that an important integration of incoming visual signals and oculomotor sig ...
... Progress has been more difficult in gaining an understanding of the somatosensory functions of this area and the possible role the IPL may play in the integration of somatosensory and visual information. It is becoming clear that an important integration of incoming visual signals and oculomotor sig ...
The Location and Function of NMDA Receptors in Cat
... tracheotomy and intravenous cannulation, the ears were locally anesthetized with viscous lidocaine (International Medical Systems, El Monte, CA) and the animal placed in a stereotaxic frame. The animal’s retinae were focused on the screen with contact lenses. The pupils were dilated with atropine me ...
... tracheotomy and intravenous cannulation, the ears were locally anesthetized with viscous lidocaine (International Medical Systems, El Monte, CA) and the animal placed in a stereotaxic frame. The animal’s retinae were focused on the screen with contact lenses. The pupils were dilated with atropine me ...
The Influence of Target Properties and the Possible
... the saccades directed in the ipsilateral direction relative to the dominant eye sometimes had faster peak velocities. This suggests that eye dominance is the main factor in this asymmetry. As previous studies they found no evidence in favor of left-right asymmetries in saccade latency. ...
... the saccades directed in the ipsilateral direction relative to the dominant eye sometimes had faster peak velocities. This suggests that eye dominance is the main factor in this asymmetry. As previous studies they found no evidence in favor of left-right asymmetries in saccade latency. ...
Multisensory Integration in the Ventral Intraparietal Area of the
... single-unit activity in two alert monkeys during the presentation of visual (drifting gratings) and tactile (low-pressure air puffs) stimuli. One stimulus was always positioned inside the receptive field of the neuron. The other stimulus was defined so as to manipulate the spatial and temporal dispa ...
... single-unit activity in two alert monkeys during the presentation of visual (drifting gratings) and tactile (low-pressure air puffs) stimuli. One stimulus was always positioned inside the receptive field of the neuron. The other stimulus was defined so as to manipulate the spatial and temporal dispa ...
The neural mechanisms of perceptual filling-in
... bar was superimposed on an ellipse, and measured the spread of attention between the bar and ellipse. They manipulated the depth order of the bar and the ellipse by changing the binocular disparity of the stimulus. In one situation, the ellipse was perceived to be in front of the bar, and the ellips ...
... bar was superimposed on an ellipse, and measured the spread of attention between the bar and ellipse. They manipulated the depth order of the bar and the ellipse by changing the binocular disparity of the stimulus. In one situation, the ellipse was perceived to be in front of the bar, and the ellips ...
Cross modality matching of brightness and loudness
... Cross modality matching is a magnitude matching procedure, developed to study the relationships between sensory modalities. Auditory and visual sensory integration can be examined through cross modality matching of brightness and loudness. Brightness and loudness are natural correlates of one anothe ...
... Cross modality matching is a magnitude matching procedure, developed to study the relationships between sensory modalities. Auditory and visual sensory integration can be examined through cross modality matching of brightness and loudness. Brightness and loudness are natural correlates of one anothe ...
Position Selectivity in Scene- and Object-Responsive
... Complex visual scenes preferentially activate several areas of the human brain, including the parahippocampal place area (PPA), the retrosplenial complex (RSC), and the transverse occipital sulcus (TOS). The sensitivity of neurons in these regions to the retinal position of stimuli is unknown, but c ...
... Complex visual scenes preferentially activate several areas of the human brain, including the parahippocampal place area (PPA), the retrosplenial complex (RSC), and the transverse occipital sulcus (TOS). The sensitivity of neurons in these regions to the retinal position of stimuli is unknown, but c ...
Organization of Visual Areas in Macaque and
... olfactory (brown, 1%). Unassigned cortex (gray, 25%) is mostly cognitive or emotional in function, but is not subdivided along these lines in the figure. ...
... olfactory (brown, 1%). Unassigned cortex (gray, 25%) is mostly cognitive or emotional in function, but is not subdivided along these lines in the figure. ...
Activity of Neurons in Anterior Inferior Temporal Cortex during a
... analysis of variance (ANOVA) and t tests, evaluated at the p < 0.05 level of significance. However, the fact that a response difference is statistically significant does not, in itself, indicate how potentially useful the difference is in discriminating among the stimuli. We were particularly intere ...
... analysis of variance (ANOVA) and t tests, evaluated at the p < 0.05 level of significance. However, the fact that a response difference is statistically significant does not, in itself, indicate how potentially useful the difference is in discriminating among the stimuli. We were particularly intere ...
Schwartz
... and spatial frequency maps were severely disturbed in the region of the focus but were unaltered in the surrounding cortex. Thus, optical imaging of intrinsic signals can be used to simultaneously map epilepsy and normal functional anatomy with high spatial resolution. ...
... and spatial frequency maps were severely disturbed in the region of the focus but were unaltered in the surrounding cortex. Thus, optical imaging of intrinsic signals can be used to simultaneously map epilepsy and normal functional anatomy with high spatial resolution. ...
The Representation of Complex Images in Spatial Frequency
... well separated SF domains in cat area 17. The relative phase of the sine wave gratings was fixed to zero, such that the pair moved as a coherent whole. Both sinusoidal components therefore moved with the same speed, but each component grating had a different TF because they had different SFs. Exampl ...
... well separated SF domains in cat area 17. The relative phase of the sine wave gratings was fixed to zero, such that the pair moved as a coherent whole. Both sinusoidal components therefore moved with the same speed, but each component grating had a different TF because they had different SFs. Exampl ...
ATTENTIONAL MODULATION OF VISUAL PROCESSING John H
... of luminance contrast, two of which (5%, bottom panel, and 10%, middle panel) were too faint to elicit a response. That is, they were both below the neuron’s contrast-response threshold. The third contrast (80%, top panel) was above the level of contrast at which the neuronal response saturated. The ...
... of luminance contrast, two of which (5%, bottom panel, and 10%, middle panel) were too faint to elicit a response. That is, they were both below the neuron’s contrast-response threshold. The third contrast (80%, top panel) was above the level of contrast at which the neuronal response saturated. The ...
Playing the electric light orchestra—how electrical stimulation of
... also tables 1 and 2). Sites are shown on schematic human and macaque brains, and indicate the visual cortical areas involved (not exact electrode positions). (a) Visual cortical sites of electrical stimulation in human patients where either a simple phosphene percept was evoked with a cortical surfa ...
... also tables 1 and 2). Sites are shown on schematic human and macaque brains, and indicate the visual cortical areas involved (not exact electrode positions). (a) Visual cortical sites of electrical stimulation in human patients where either a simple phosphene percept was evoked with a cortical surfa ...
Postnatal growth and column spacing in cat primary visual cortex
... sections of the visual cortical hemispheres were digitized in 8-bit greyscales with a resolution of 20.48 pixels/mm using an image processing system (Imago II, Compulog). Area 17 was delineated on the digitized autoradiographs using the distinct 2-DG activation pattern in that area compared to surro ...
... sections of the visual cortical hemispheres were digitized in 8-bit greyscales with a resolution of 20.48 pixels/mm using an image processing system (Imago II, Compulog). Area 17 was delineated on the digitized autoradiographs using the distinct 2-DG activation pattern in that area compared to surro ...
Neural correlates for perception of 3d surface orientation from texture
... disparity signals have been found in the parietal (11, 12) and temporal (13, 14) association cortices. However, binocular disparity is not the only cue for depth perception, because we can perceive depth even with one eye closed. Gibson (15) has proposed that texture gradient is an important cue for ...
... disparity signals have been found in the parietal (11, 12) and temporal (13, 14) association cortices. However, binocular disparity is not the only cue for depth perception, because we can perceive depth even with one eye closed. Gibson (15) has proposed that texture gradient is an important cue for ...
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.