Color Processing in Macaque Striate Cortex: Relationships to Ocular Dominance, Cytochrome Oxidase, and Orientation

• Published in: Journal of neurophysiology Vol. 87; no. 6; pp. 3126 - 3137
• Main Authors: Landisman, Carole E, Ts'o, Daniel Y
• Format: Journal Article
• Language: English
• Published: United States Am Phys Soc 01-06-2002
• Subjects: Animals; Brain Mapping; Color Perception - physiology; Electron Transport Complex IV - analysis; Electron Transport Complex IV - physiology; Electrophysiology; Macaca fascicularis; Neurons - enzymology; Orientation - physiology; Photic Stimulation; Visual Cortex - physiology
• ISSN: 0022-3077; 1522-1598
• DOI: 10.1152/jn.2002.87.6.3126

The Rockefeller University, New York, New York 10021; and
Baylor College of Medicine, Houston, Texas 77030
Landisman, Carole E. and
Daniel Y. Ts'o.
Color Processing in Macaque Striate Cortex: Relationships to
Ocular Dominance, Cytochrome Oxidase, and Orientation. J. Neurophysiol. 87: 3126-3137, 2002. We located
clusters of color-selective neurons in macaque striate cortex, as
mapped with optical imaging and confirmed with electrophysiological
recordings. By comparing responses to an equiluminant red/green
stimulus versus a high-contrast luminance stimulus, we were able to
reveal a patchy distribution of color selectivity. Other color imaging
protocols, when compared with electrophysiological data, did not
reliably indicate the location of functional structures. The imaged
color patches were compared with other known functional subdivisions of
striate cortex. There was a high degree of overlap of the color patches
with the cytochrome-oxidase (CO) blobs. The patches were often larger
than a single blob in size, however, and in some instances spanned two
neighboring blobs. More than one-half (56%) of the color-selective
patches seen in optical imaging were not confined to one ocular
dominance (OD) column. Almost one-quarter of color patches (23%)
extended across OD columns to encompass two blobs of different eye
preference. We also compared optical images of orientation selectivity
to maps of color selectivity. Results indicate that the layout of orientation and color selectivity are not directly related.
Specifically, despite having similar scales and distributions, the maps
of orientation and color selectivity were not in consistent alignment
or registration. Further, we find that the maps of color selectivity
and of orientation are each only loosely related to maps of OD. This
description stands in contrast to a common depiction of color-selective
regions as identical to CO blobs, appearing as pegs in the centers of OD columns in the classical "ice cube" model. These results
concerning the pattern of color selectivity in V1 support the
view (put forth in previous imaging studies of the organization of
orientation and ocular dominance) that there is not a fundamental
registration of functional hypercolumns in V1.