Is there a high concentration of color-selective cells in area V4 of monkey visual cortex?

1982 ◽  
Vol 47 (2) ◽  
pp. 193-213 ◽  
Author(s):  
S. J. Schein ◽  
R. T. Marrocco ◽  
F. M. de Monasterio
Keyword(s):  
Visual Cortex ◽  
Central Field ◽  
High Concentration ◽  
Field Representation ◽  
Area V4 ◽  
Area V2 ◽  
Sufficient Detail ◽  
Prelunate Gyrus ◽  
Color Selectivity ◽  
Monkey Visual Cortex

1. Recordings were made from neurons located within the central-field representation of the V4 area of extrastriate visual cortex using a semichronic, nitrous-oxide preparation; the properties of 174 cells were examined in sufficient detail to permit their classification. Cyto- and myeloarchitectural studies confirmed the identification of the area. 2. Color-selective cells with either color-biased or color-opponent properties represented about 20% of the examined population. Their incidence was not significantly different from that of similar cells encountered in penetrations into the central-field representation of area V2. 3. Most color-selective cells had color-biased properties, responding best to wave-lengths shorter than 460 nm, or longer than 580 n, or both. No examples of "green-biased" cells were found. Some color-biased cells responded to photopically matched white light, while others did not. Very few cells showed overt color-opponent responses. The spectral sensitivity of color-selective cells was not unusually narrow. 4. Cells lacking color selectivity and responding equally well to chromatic and achromatic lights of equal photopic luminosity, were the most commonly encountered cell type in penetrations of different parts of the V4 area (56%). Other than color, these cells showed stimulus preferences like those of color-selective cells. 5. One-fourth of V4 cells could not be systematically driven with the various stimuli used. This finding is consistent with recent results of recordings from the prelunate gyrus of the behaving monkey suggesting that some V4 cells receive extraretinal signals. 6. Our results do not support recent claims that V4 is specialized in the detailed analysis of color information.

Shape perception via a high-channel-count neuroprosthesis in monkey visual cortex

Science ◽  
2020 ◽  
Vol 370 (6521) ◽  
pp. 1191-1196 ◽  
Author(s):  
Xing Chen ◽  
Feng Wang ◽  
Eduardo Fernandez ◽  
Pieter R. Roelfsema
Keyword(s):  
Electrical Stimulation ◽  
Visual Cortex ◽  
Receptive Fields ◽  
Shape Perception ◽  
Area V4 ◽  
Multiple Electrodes ◽  
The World ◽  
Functional Vision ◽  
Monkey Visual Cortex

Blindness affects 40 million people across the world. A neuroprosthesis could one day restore functional vision in the blind. We implanted a 1024-channel prosthesis in areas V1 and V4 of the visual cortex of monkeys and used electrical stimulation to elicit percepts of dots of light (called phosphenes) on hundreds of electrodes, the locations of which matched the receptive fields of the stimulated neurons. Activity in area V4 predicted phosphene percepts that were elicited in V1. We simultaneously stimulated multiple electrodes to impose visible patterns composed of a number of phosphenes. The monkeys immediately recognized them as simple shapes, motions, or letters. These results demonstrate the potential of electrical stimulation to restore functional, life-enhancing vision in the blind.

scholarly journals Metabolic Activity Patterns in the Monkey Visual Cortex as Revealed by Spectral Analysis

1999 ◽  
Vol 19 (4) ◽  
pp. 401-416 ◽  
Author(s):  
Yannis Dalezios ◽  
Georgia G. Gregoriou ◽  
Helen E. Savaki
Keyword(s):  
Spectral Analysis ◽  
Visual Cortex ◽  
Metabolic Activity ◽  
Activity Patterns ◽  
Spatial Arrangement ◽  
Spectral Amplitude ◽  
Two Dimensional ◽  
Reaching Task ◽  
Area V2 ◽  
Monkey Visual Cortex

The metabolic activity pattern of the monkey visual cortex was mapped quantitatively with [14C]-2-deoxyglucose during the performance of a visually guided reaching task. After bandpass filtering of the reconstructed two-dimensional metabolic maps of areas V1 and V2, alternating bands of high and low metabolic activity were apparent in control and experimental hemispheres. The spatial arrangement of active bands was studied with two-dimensional spectral analysis, and bands were found to be more organized in the experimental monkey. In area V1 of the control monkey the spectral amplitude was spread over a wider range of directions and frequencies than in the experimental subject. The finding that layer IV is characterized by more complex spectra than layers I through III suggests the coexistence of more than one active columnar system in the geniculorecipient layer. In area V2, stripes running almost perpendicular to the V1/V2 border were found along with superimposed patches of enhanced metabolic activity. In the experimental hemispheres, the corresponding spectra were extremely sharp yielding a constant periodicity. It is suggested that the well-organized columnar arrangement within areas V1 and V2 of the experimental hemispheres emerges from the diffusely organized background network of activity patterns in the control state.

scholarly journals Curvature domains in V4 of Macaque Monkey

2020 ◽  
Author(s):  
Jiaming Hu ◽  
Xue Mei Song ◽  
Qiannan Wang ◽  
Anna Wang Roe
Keyword(s):  
Visual Cortex ◽  
Optical Imaging ◽  
Functional Organization ◽  
Macaque Monkey ◽  
Visual Object ◽  
Shape Information ◽  
Object Shape ◽  
Area V4 ◽  
Monkey Visual Cortex ◽  
Visual Cortical

AbstractAn important aspect of visual object recognition is the ability to perceive object shape. How the brain encodes fundamental aspects of shape information remains poorly understood. Models of object shape representation describe a multi-stage process that includes encoding of contour orientation and curvature. While modules encoding contour orientation are well established (orientation domains in V1 and V2 visual cortical areas), whether there are modules for curvature is unknown. In this study, we identify a module for curvature representation in area V4 of monkey visual cortex and illustrate a systematic representation of low to high curvature and of curvature orientation, indicative of curvature hypercolumns in V4. We suggest that identifying systematic modular organizations at each stage of the visual cortical hierarchy signifies the key computations performed.SignificanceWe use intrinsic signal optical imaging in area V4 of anesthetized macaque monkey to study the functional organization of curvature representation. We find a modular basis for cue-invariant curvature representation in area V4 of monkey visual cortex and illustrate a systematic representation from low to high curvature and of curvature orientation, replete with curvature pinwheels. This is the first report of systematic functional organization for curvature representation in the visual system. The use of optical imaging has revealed at a population level spatial details of cortical responses, something which has not been evident from previous studies of single neurons. These data support a representational architecture underlying a ‘curvature hypercolumn’ in V4.

scholarly journals Myelin densities in retinotopically defined dorsal visual areas of the macaque

2021 ◽  
Author(s):  
Xiaolian Li ◽  
Qi Zhu ◽  
Wim Vanduffel
Keyword(s):  
Visual Cortex ◽  
Visual Field ◽  
Cortical Thickness ◽  
New World Monkeys ◽  
Isotropic Resolution ◽  
Density Mapping ◽  
Area V2 ◽  
Visual Areas ◽  
Density Results

AbstractThe visuotopic organization of dorsal visual cortex rostral to area V2 in primates has been a longstanding source of controversy. Using sub-millimeter phase-encoded retinotopic fMRI mapping, we recently provided evidence for a surprisingly similar visuotopic organization in dorsal visual cortex of macaques compared to previously published maps in New world monkeys (Zhu and Vanduffel, Proc Natl Acad Sci USA 116:2306–2311, 2019). Although individual quadrant representations could be robustly delineated in that study, their grouping into hemifield representations remains a major challenge. Here, we combined in-vivo high-resolution myelin density mapping based on MR imaging (400 µm isotropic resolution) with fine-grained retinotopic fMRI to quantitatively compare myelin densities across retinotopically defined visual areas in macaques. Complementing previously documented differences in populational receptive-field (pRF) size and visual field signs, myelin densities of both quadrants of the dorsolateral posterior area (DLP) and area V3A are significantly different compared to dorsal and ventral area V3. Moreover, no differences in myelin density were observed between the two matching quadrants belonging to areas DLP, V3A, V1, V2 and V4, respectively. This was not the case, however, for the dorsal and ventral quadrants of area V3, which showed significant differences in MR-defined myelin densities, corroborating evidence of previous myelin staining studies. Interestingly, the pRF sizes and visual field signs of both quadrant representations in V3 are not different. Although myelin density correlates with curvature and anticorrelates with cortical thickness when measured across the entire cortex, exactly as in humans, the myelin density results in the visual areas cannot be explained by variability in cortical thickness and curvature between these areas. The present myelin density results largely support our previous model to group the two quadrants of DLP and V3A, rather than grouping DLP- with V3v into a single area VLP, or V3d with V3A+ into DM.

scholarly journals A direct interareal feedback-to-feedforward circuit in primate visual cortex

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Caitlin Siu ◽  
Justin Balsor ◽  
Sam Merlin ◽  
Frederick Federer ◽  
Alessandra Angelucci
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Projection Neurons ◽  
V1 Neurons ◽  
Cortical Areas ◽  
Area V2 ◽  
Computational Work ◽  
Primate Visual Cortex ◽  
Similar Area ◽  
Hierarchical Computation

AbstractThe mammalian sensory neocortex consists of hierarchically organized areas reciprocally connected via feedforward (FF) and feedback (FB) circuits. Several theories of hierarchical computation ascribe the bulk of the computational work of the cortex to looped FF-FB circuits between pairs of cortical areas. However, whether such corticocortical loops exist remains unclear. In higher mammals, individual FF-projection neurons send afferents almost exclusively to a single higher-level area. However, it is unclear whether FB-projection neurons show similar area-specificity, and whether they influence FF-projection neurons directly or indirectly. Using viral-mediated monosynaptic circuit tracing in macaque primary visual cortex (V1), we show that V1 neurons sending FF projections to area V2 receive monosynaptic FB inputs from V2, but not other V1-projecting areas. We also find monosynaptic FB-to-FB neuron contacts as a second motif of FB connectivity. Our results support the existence of FF-FB loops in primate cortex, and suggest that FB can rapidly and selectively influence the activity of incoming FF signals.

A role for the corpus callosum in visual area V4 of the macaque

1993 ◽  
Vol 10 (1) ◽  
pp. 159-171 ◽  
Author(s):  
Robert Desimone ◽  
Jeffrey Moran ◽  
Stanley J. Schein ◽  
Mortimer Mishkin
Keyword(s):  
Visual Field ◽  
Corpus Callosum ◽  
Anterior Commissure ◽  
Color Constancy ◽  
Receptive Fields ◽  
Optic Tract ◽  
Complete Suppression ◽  
Central Visual Field ◽  
Field Representation ◽  
Area V4

AbstractThe classically defined receptive fields of V4 cells are confined almost entirely to the contralateral visual field. However, these receptive fields are often surrounded by large, silent suppressive regions, and stimulating the surrounds can cause a complete suppression of response to a simultaneously presented stimulus within the receptive field. We investigated whether the suppressive surrounds might extend across the midline into the ipsilateral visual field and, if so, whether the surrounds were dependent on the corpus callosum, which has a widespread distribution in V4. We found that the surrounds of more than half of the cells tested in the central visual field representation of V4 crossed into the ipsilateral visual field, with some extending up to at least 16 deg from the vertical meridian. Much of this suppression from the ipsilateral field was mediated by the corpus callosum, as section of the callosum dramatically reduced both the strength and extent of the surrounds. There remained, however, some residual suppression that was not further reduced by addition of an anterior commissure lesion. Because the residual ipsilateral suppression was similar in magnitude and extent to that found following section of the optic tract contralateral to the V4 recording, we concluded that it was retinal in origin. Using the same techniques employed in V4, we also mapped the ipsilateral extent of surrounds in the foveal representation of VI in an intact monkey. Results were very similar to those in V4 following commissural or contralateral tract sections. The findings suggest that V4 is a central site for long-range interactions both within and across the two visual hemifields. Taken with previous work, the results are consistent with the notion that the large suppressive surrounds of V4 neurons contribute to the neural mechanisms of color constancy and figure-ground separation.

Orientation anisotropy in monkey visual cortex

1978 ◽  
Vol 149 (1) ◽  
pp. 229-234 ◽  
Author(s):  
R.J.W. Mansfield ◽  
S.F. Ronner]
Keyword(s):  
Visual Cortex ◽  
Orientation Anisotropy ◽  
Monkey Visual Cortex
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