Cite as:
Lee R J, Mollon J, Zaidi Q, Smithson H, 2007, "Adaptation of central colour channels" Perception 36 ECVP Abstract Supplement

Adaptation of central colour channels

R J Lee, J Mollon, Q Zaidi, H Smithson

The opponent stages of early colour processing are thought to combine to feed multiple cortical channels, each maximally responsive to a different chromaticity. We investigated the perceptual adaptation of these central colour channels. A stimulus that is modulated in time around a circular locus in the isoluminant plane of colour space provides sinusoidal modulation to each of the cone classes, and to each of the colour-opponent mechanisms. The amplitudes of these signals are the same for clockwise and counterclockwise modulations. However, owing to latency differences between the opponent mechanisms, the amplitude of the combined signal that reaches the cortex at each stimulus phase will be different for the two modulations (Stromeyer et al, 1991 Vision Research 31 787 - 803). Chromatic discrimination thresholds were measured along eight chromatic directions, before and after adaptation to hue circle stimuli. The pattern of threshold increases was different following adaptation to clockwise or counterclockwise modulation. These differences have allowed us to infer the adaptation characteristics of central colour channels.

[Supported by Durham University Doctoral Fellowship.]

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