TY - JOUR
T1 - A contrast and surface code explains complex responses to black and white stimuli in V1
AU - Zurawel, Guy
AU - Ayzenshtat, Inbal
AU - Zweig, Shay
AU - Shapley, Robert
AU - Slovin, Hamutal
N1 - Publisher Copyright:
© 2014 the authors.
PY - 2014/10/22
Y1 - 2014/10/22
N2 - We investigated the cortical mechanisms underlying the visual perception of luminance-defined surfaces and the preference for black over white stimuli in the macaque primary visual cortex, V1. We measured V1 population responses with voltage-sensitive dye imaging in fixating monkeys that were presented with white or black squares of equal contrast around a mid-gray. Regions corresponding to the squares’ edges exhibited higher activity than those corresponding to the center. Responses to black were higher than to white, surprisingly to a much greater extent in the representation of the square’s center. Additionally, the square-evoked activation patterns exhibited spatial modulations along the edges and corners.Amodel comprised of neural mechanisms that compute local contrast, local luminance temporal modulations in the black and white directions, and cortical center-surround interactions, could explain the observed population activity patterns in detail. The model captured the weaker contribution of V1 neurons that respond to positive (white) and negative (black) luminance surfaces, and the stronger contribution of V1 neurons that respond to edge contrast. Also, the model demonstrated how the response preference for black could be explained in terms of stronger surface-related activation to negative luminance modulation. The spatial modulations along the edges were accounted for by surround suppression. Overall the results reveal the relative strength of edge contrast and surface signals in the V1 response to visual objects.
AB - We investigated the cortical mechanisms underlying the visual perception of luminance-defined surfaces and the preference for black over white stimuli in the macaque primary visual cortex, V1. We measured V1 population responses with voltage-sensitive dye imaging in fixating monkeys that were presented with white or black squares of equal contrast around a mid-gray. Regions corresponding to the squares’ edges exhibited higher activity than those corresponding to the center. Responses to black were higher than to white, surprisingly to a much greater extent in the representation of the square’s center. Additionally, the square-evoked activation patterns exhibited spatial modulations along the edges and corners.Amodel comprised of neural mechanisms that compute local contrast, local luminance temporal modulations in the black and white directions, and cortical center-surround interactions, could explain the observed population activity patterns in detail. The model captured the weaker contribution of V1 neurons that respond to positive (white) and negative (black) luminance surfaces, and the stronger contribution of V1 neurons that respond to edge contrast. Also, the model demonstrated how the response preference for black could be explained in terms of stronger surface-related activation to negative luminance modulation. The spatial modulations along the edges were accounted for by surround suppression. Overall the results reveal the relative strength of edge contrast and surface signals in the V1 response to visual objects.
KW - Black response
KW - Monkey
KW - Primary visual cortex
KW - Surface
KW - Voltage-sensitive dye imaging
KW - White response
UR - http://www.scopus.com/inward/record.url?scp=84908056749&partnerID=8YFLogxK
U2 - 10.1523/JNEUROSCI.0848-14.2014
DO - 10.1523/JNEUROSCI.0848-14.2014
M3 - ???researchoutput.researchoutputtypes.contributiontojournal.article???
C2 - 25339751
AN - SCOPUS:84908056749
SN - 0270-6474
VL - 34
SP - 14388
EP - 14402
JO - Journal of Neuroscience
JF - Journal of Neuroscience
IS - 43
ER -