Facilitatory interactions of chromatic and luminance signals in man

J. D. Victor, M. M. Conte, R. Rahim, K. P. Purpura

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Purpose. Many psychophysical studies have demonstrated interactions of color and luminance information in a variety of simple visual tasks. Here, we characterize the dynamics of the interaction of color and luminance signals, as measured by the human visual evoked potential. Methods. Visual evoked potentials were recorded in response to sinusoidal luminance gratings (2 c/deg) square-wave modulated at 4 Hz (F1), presented at a mean luminance of 52 cd/m2 and a contrast of 0.125. A standing 2 c/deg grating was superimposed on the modulated grating for 4 sec and then removed for 4 sec. 64 passes through this 8-second stimulus cycle were collected for VEP analysis. The standing gratings varied in chromatic and luminance composition, and included sequences of stimuli which traversed the isoluminant plane. Results. As expected (Bodis-Wollner & Hendley 1979), during the 4 sec in which a luminance grating was added, we recorded a response at the frequency of the modulated grating (F1). However, addition of standing isoluminant gratings also elicited a significant F1 response. Addition of a mixed chromatic and luminance grating elicited a larger F1 response than that produced by addition of its luminance component alone. These interactions occurred with no detectable lag, persisted as long as the standing grating was present, and disappeared when it was removed. Conclusions. Chromatic inputs interact nonlinearly with luminance inputs and enhance the size of spatial contrast signals.

Original languageEnglish
Pages (from-to)S3
JournalInvestigative Ophthalmology and Visual Science
Volume37
Issue number3
StatePublished - 15 Feb 1996
Externally publishedYes

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