RT Journal Article
SR Electronic
T1 Two Distinct Mechanisms of Suppression in Human Vision
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 8704
OP 8707
DO 10.1523/JNEUROSCI.2871-05.2005
VO 25
IS 38
A1 Petrov, Yury
A1 Carandini, Matteo
A1 McKee, Suzanne
YR 2005
UL http://www.jneurosci.org/content/25/38/8704.abstract
AB Cortical visual neurons in the cat and monkey are inhibited by stimuli surrounding their receptive fields (surround suppression) or presented within their receptive fields (cross-orientation or overlay suppression). We show that human contrast sensitivity is similarly affected by two distinct suppression mechanisms. In agreement with the animal studies, human surround suppression is tightly tuned to the orientation and spatial frequency of the test, unlike overlay suppression. Using a double-masking paradigm, we also show that in humans, overlay suppression precedes surround suppression in the processing sequence. Surprisingly, we find that, unlike overlay suppression, surround suppression is only strong in the periphery (>1° eccentricity). This result argues for a new functional distinction between foveal and peripheral operations.