Categorical clustering of the neural representation of color.
Cortical activity was measured with functional magnetic resonance imaging (fMRI) while human subjects viewed 12 stimulus colors and performed either a color-naming or diverted attention task. A forward model was used to extract lower dimensional neural color spaces from the high-dimensional fMRI responses. The neural color spaces in two visual areas, human ventral V4 (V4v) and VO1, exhibited clustering (greater similarity between activity patterns evoked by stimulus colors within a perceptual category, compared to between-category colors) for the color-naming task, but not for the diverted attention task. Response amplitudes and signal-to-noise ratios were higher in most visual cortical areas for color naming compared to diverted attention. But only in V4v and VO1 did the cortical representation of color change to a categorical color space. A model is presented that induces such a categorical representation by changing the response gains of subpopulations of color-selective neurons.
New York University, Center for Neural Science, Department of Psychology, New York, New York, 10003.
Gijs Joost
GJ
Brouwer
David J
DJ
Heeger
D000328:Adult; D001288:Attention; D016000:Cluster Analysis; D003118:Color Perception; D005260:Female; D006801:Humans; D008297:Male; D008959:Models, Neurological; D009474:Neurons / Q000502:physiology; D014793:Visual Cortex / Q000166:cytology / Q000502:physiology*