Form Processing Modules in Primate Area V4

1997 ◽  
Vol 77 (4) ◽  
pp. 2191-2196 ◽  
Author(s):  
Geoffrey M. Ghose ◽  
Daniel Y. Ts'O
Keyword(s):  
Optical Imaging ◽  
Functional Organization ◽  
Visual Fields ◽  
Central Position ◽  
Unit Recording ◽  
Form Analysis ◽  
Area V4 ◽  
Form Processing ◽  
Object Based

Ghose, Geoffrey M. and Daniel Y. Ts'o. Form processing modules in primate area V4. J. Neurophysiol. 77: 2191–2196, 1997. Area V4 occupies a central position among the areas of the primate cerebral cortex involved with object recognition and analysis. Consistent with this role, neurons in V4 are selective for many visual attributes including color, orientation, and binocular disparity. However, it is uncertain whether cells within V4 are organized with respect to these properties. In this study we used in vivo optical imaging and electrophysiology in macaque visual cortex to show that cells that share certain physiological properties are indeed grouped together in V4. Our results revealed regions containing cells with common orientation selectivity. These regions were similar in size to those seen in V2 and much larger than those seen in V1 and were confirmed by appropriately targeted single-unit recording. Surprisingly, orientation organization visible through imaging was limited to the portion of V4 representing the central visual fields. Optical imaging also revealed a functional organization related to stimulus size. Size-sensitive regions (S regions) contained cells that were strongly suppressed by large stimuli. In contrast to V2, S regions in V4 contain orientation domains. These results suggest that V4 contains modular assemblies of cells related to particular aspects of form analysis. Such organization may contribute to the construction of object-based representations.

Organization of Color-Selective Neurons in Macaque Visual Area V4

2009 ◽  
Vol 102 (1) ◽  
pp. 15-27 ◽  
Author(s):  
Yasuyo Kotake ◽  
Hiroshi Morimoto ◽  
Yasutaka Okazaki ◽  
Ichiro Fujita ◽  
Hiroshi Tamura
Keyword(s):  
Functional Organization ◽  
Color Discrimination ◽  
Cortical Surface ◽  
Moderate Correlation ◽  
Unit Recording ◽  
Color Preferences ◽  
Area V4 ◽  
Columnar Organization ◽  
Color Selectivity ◽  
V4 Neurons

Cortical area V4 in monkeys contains neurons that respond selectively to particular colors. It has been controversial how these color-selective neurons are spatially organized in V4. One view asserts that color-selective neurons are organized in columns with different colors orderly mapped across the cortex, whereas other studies have found no evidence for columnar organization or any other clustered structure. In the present study, we reexamined the functional organization of color-selective neurons in area V4 by quantitatively evaluating and comparing the color selectivity of nearby neurons as well as those encountered along electrode penetrations. Using a multiple single-unit recording technique, we recorded extracellular activities simultaneously from groups of nearby V4 neurons. Color discrimination and color preferences exhibited a moderate correlation between nearby neurons, consistent with neurons in a local region of V4 sharing similar responses to stimulus color. However, the degree of clustering was variable across recording sites. Some regions contained neurons with similar color preferences, whereas others contained neurons with diverse color preferences. Neurons in penetrations normal to the cortical surface responded to an overlapping range of colors and maintained a moderate correlation. Neurons in penetrations tangential to the cortical surface differed dramatically in their preferred color and exhibited a negative correlation. We conclude that neurons in area V4 are moderately clustered according to their color selectivity and that this weak clustering is columnar in structure.

scholarly journals Spatial structure of neuronal receptive field in awake monkey secondary visual cortex (V2)

2016 ◽  
Vol 113 (7) ◽  
pp. 1913-1918 ◽  
Author(s):  
Lu Liu ◽  
Liang She ◽  
Ming Chen ◽  
Tianyi Liu ◽  
Haidong D. Lu ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Receptive Field ◽  
Optical Imaging ◽  
Visual Processing ◽  
Single Unit ◽  
Functional Organization ◽  
Projection Pursuit ◽  
Unit Recording ◽  
Visual Neurons ◽  
Aspect Ratios

Visual processing depends critically on the receptive field (RF) properties of visual neurons. However, comprehensive characterization of RFs beyond the primary visual cortex (V1) remains a challenge. Here we report fine RF structures in secondary visual cortex (V2) of awake macaque monkeys, identified through a projection pursuit regression analysis of neuronal responses to natural images. We found that V2 RFs could be broadly classified as V1-like (typical Gabor-shaped subunits), ultralong (subunits with high aspect ratios), or complex-shaped (subunits with multiple oriented components). Furthermore, single-unit recordings from functional domains identified by intrinsic optical imaging showed that neurons with ultralong RFs were primarily localized within pale stripes, whereas neurons with complex-shaped RFs were more concentrated in thin stripes. Thus, by combining single-unit recording with optical imaging and a computational approach, we identified RF subunits underlying spatial feature selectivity of V2 neurons and demonstrated the functional organization of these RF properties.

Functional parasagittal compartments in the rat cerebellar cortex: an in vivo optical imaging study using neutral red

1996 ◽  
Vol 76 (6) ◽  
pp. 4169-4174 ◽  
Author(s):  
G. Chen ◽  
C. L. Hanson ◽  
T. J. Ebner
Keyword(s):  
Optical Imaging ◽  
Cerebellar Cortex ◽  
Functional Organization ◽  
Imaging Techniques ◽  
Imaging Study ◽  
Neutral Red ◽  
Zebrin Ii ◽  
Optical Responses ◽  
Crus I

1. The spatial patterns of activation in the rat cerebellar cortex evoked by peripheral stimulation were studied in vivo using optical imaging techniques. 2. Crus I and Crus II were stained with the pH sensitive dye, neutral red. Electrical stimulation of the vibrissae area of the ipsilateral face evoked optical responses consisting of parasagittal bands. The bands were 100–300 microns in width, elongated in the anterior-posterior direction, commonly extended across at least two folia, and varied in number from 1 to 7. 3. The optical responses were dependent on activation of postsynaptic elements since they were decreased substantially by the non-N-methyl-D-aspartate antagonist, 6-cyano-7-nitroquinoxaline-2,3-dione. The optical bands were shown to correspond anatomically with the parasagittal compartments revealed by immunostaining with anti-zebrin II. 4. The present study demonstrates that functional parasagittal compartments exist in the rat cerebellar cortex and suggests that zebrin-positive Purkinje cell subgroups are anatomically related to this functional organization.

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.

Optical imaging probes and their potential contribution to radiotracer development

2016 ◽  
Vol 55 (02) ◽  
pp. 51-62 ◽  
Author(s):  
S. Hermann ◽  
M. Schäfers ◽  
C. Höltke ◽  
A. Faust
Keyword(s):  
Optical Imaging ◽  
Fluorescent Dyes ◽  
Great Influence ◽  
Potential Contribution ◽  
Preclinical Evaluation ◽  
Guided Surgery ◽  
Fluorescence Guided Surgery ◽  
Imaging Probes ◽  
Unspecific Binding

SummaryOptical imaging has long been considered a method for histological or microscopic investigations. Over the last 15 years, however, this method was applied for preclinical molecular imaging and, just recently, was also able to show its principal potential for clinical applications (e.g. fluorescence-guided surgery). Reviewing the development and preclinical evaluation of new fluorescent dyes and target-specific dye conjugates, these often show characteristic patterns of their routes of excretion and biodistribution, which could also be interesting for the development and optimization of radiopharmaceuticals. Especially ionic charges show a great influence on biodistribution and netcharge and charge-distribution on a conjugate often determines unspecific binding or background signals in liver, kidney or intestine, and other organs.Learning from fluorescent probe behaviour in vivo and translating this knowledge to radio-pharmaceuticals might be useful to further optimize emerging and existing radiopharmaceuticals with respect to their biodistribution and thereby availability for binding to their targets.

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