Abstract

Psychophysical sensitivity to red–green chromatic modulation decreases with visual eccentricity, compared to sensitivity to luminance modulation, even after appropriate stimulus scaling. This is likely to occur at a central, rather than a retinal, site. Blood-oxygenation-level-dependent (BOLD) functional magnetic resonance imaging (fMRI) responses to stimuli designed to separately stimulate different afferent channels’ [red–green, luminance, and short-wavelength (S)-cone] circular gratings were recorded as a function of visual eccentricity (±10deg) and spatial frequency (SF) in human primary visual cortex (V1) and further visual areas (V2v, V3v). In V1, the SF tuning of BOLD fMRI responses became coarser with eccentricity. For red–green and luminance gratings, similar SF tuning curves were found at all eccentricities. The pattern for S-cone modulation differed, with SF tuning changing more slowly with eccentricity than for the other two modalities. This may be due to the different retinal distribution with eccentricity of this receptor type. A similar pattern held in V2v and V3v. This would suggest that transformation or spatial filtering of the chromatic (red–green) signal occurs beyond these areas.

© 2016 Optical Society of America

Full Article  |  PDF Article
OSA Recommended Articles
Spatial distributions of cone inputs to cells of the parvocellular pathway investigated with cone-isolating gratings

Barry B. Lee, Robert M. Shapley, Michael J. Hawken, and Hao Sun
J. Opt. Soc. Am. A 29(2) A223-A232 (2012)

Color tuning in alert macaque V1 assessed with fMRI and single-unit recording shows a bias toward daylight colors

Rosa Lafer-Sousa, Yang O. Liu, Luis Lafer-Sousa, Michael C. Wiest, and Bevil R. Conway
J. Opt. Soc. Am. A 29(5) 657-670 (2012)

Color coding in the primate visual pathway: a historical view

Barry B. Lee
J. Opt. Soc. Am. A 31(4) A103-A112 (2014)

References

You do not have subscription access to this journal. Citation lists with outbound citation links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Cited By

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Figures (6)

You do not have subscription access to this journal. Figure files are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Equations (1)

You do not have subscription access to this journal. Equations are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Metrics

You do not have subscription access to this journal. Article level metrics are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription