TY - JOUR
T1 - Spatial frequency modulates color selectivity of adaptation to contrast patterns
AU - Heckman, Genevieve M.
AU - Engel, Stephen A.
N1 - Copyright:
Copyright 2004 Elsevier B.V., All rights reserved.
PY - 2003
Y1 - 2003
N2 - Single-unit recordings in macaque V1 have identified two populations of color selective cells. One contains neurons that prefer low spatial frequencies and respond best to red-green (L-M cone contrast). Another contains neurons that prefer higher spatial frequencies; some of these cells respond best to L-M, but most respond best to "non-cardinal" directions (e.g., M cone contrast). The goal of this study was to identify perceptual mechanisms consistent with these two sets of neurons. We used a selective adaptation procedure with two types of adapting stimuli targeted to each set of neurons. Subjects adapted to Gaussian blobs and 2 cyc/deg Gabor patterns, each containing L-M or M cone contrast. After viewing a 3 deg adapting stimulus in one hemifield, subjects adjusted the contrast of a stimulus in the unadapted field to match the appearance of a test stimulus (either L-M, M, L or L+M cone contrast) presented in the adapted field. Adapting to Gabor L-M patterns reduced the apparent contrast of L-M tests more than the other tests. Similarly, adapting to a Gabor M pattern reduced the apparent contrast of M tests more than the others. Adapting to a Gaussian L-M pattern reduced the apparent contrast of the L-M test most, but, critically, adapting to a Gaussian M pattern reduced the apparent contrast of M and L-M patterns to an equal degree. Selective adaptation is most frequently interpreted as reduced responsiveness of a mechanism that prefers the most strongly affected test. Accordingly, our results indicate that adapting to Gabor stimuli can reduce the responsiveness of mechanisms that prefer non-cardinal directions. Adapting to Gaussian stimuli mainly reduces the responsiveness of mechanisms that prefer L-M, but does not appear to greatly affect non-cardinal mechanisms. Our data suggest that low and high spatial frequency patterns are encoded by two separable populations of color selective neurons, both of which contribute to color appearance.
AB - Single-unit recordings in macaque V1 have identified two populations of color selective cells. One contains neurons that prefer low spatial frequencies and respond best to red-green (L-M cone contrast). Another contains neurons that prefer higher spatial frequencies; some of these cells respond best to L-M, but most respond best to "non-cardinal" directions (e.g., M cone contrast). The goal of this study was to identify perceptual mechanisms consistent with these two sets of neurons. We used a selective adaptation procedure with two types of adapting stimuli targeted to each set of neurons. Subjects adapted to Gaussian blobs and 2 cyc/deg Gabor patterns, each containing L-M or M cone contrast. After viewing a 3 deg adapting stimulus in one hemifield, subjects adjusted the contrast of a stimulus in the unadapted field to match the appearance of a test stimulus (either L-M, M, L or L+M cone contrast) presented in the adapted field. Adapting to Gabor L-M patterns reduced the apparent contrast of L-M tests more than the other tests. Similarly, adapting to a Gabor M pattern reduced the apparent contrast of M tests more than the others. Adapting to a Gaussian L-M pattern reduced the apparent contrast of the L-M test most, but, critically, adapting to a Gaussian M pattern reduced the apparent contrast of M and L-M patterns to an equal degree. Selective adaptation is most frequently interpreted as reduced responsiveness of a mechanism that prefers the most strongly affected test. Accordingly, our results indicate that adapting to Gabor stimuli can reduce the responsiveness of mechanisms that prefer non-cardinal directions. Adapting to Gaussian stimuli mainly reduces the responsiveness of mechanisms that prefer L-M, but does not appear to greatly affect non-cardinal mechanisms. Our data suggest that low and high spatial frequency patterns are encoded by two separable populations of color selective neurons, both of which contribute to color appearance.
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U2 - 10.1167/3.9.312
DO - 10.1167/3.9.312
M3 - Article
AN - SCOPUS:4243096260
SN - 1534-7362
VL - 3
SP - 312a
JO - Journal of vision
JF - Journal of vision
IS - 9
ER -