Surround suppression by high spatial frequency stimuli in the cat primary visual cortex.
Surround suppression is a phenomenon whereby stimulation of the extraclassical receptive field suppressively modulates the visual responses of neurons in the primary visual cortex (V1) (also known as area 17). It is known that surround suppression tunes to spatial frequencies (SFs) that are much lower and broader than the frequencies to which the classical receptive field tunes. In this study, we tested the effects of varying SFs on surround suppression by using a circular sinusoidal grating patch that covered both the classical receptive field and the extraclassical receptive field. Using area-summation tuning curves, we found high-SF-tuned surround suppression in the cat V1. This high-SF-tuned surround suppression causes the SF tuning to shift to low SF for large stimuli. By simulating a model neuron lacking a suppressive surround mechanism, we confirmed that these preferred SF shifts do not occur in the absence of surround suppression. We surmise that the high-SF-tuned suppression, which shifts the preferred SF according to size, functionally contributes to the scale-invariant processing of visual images in V1.
Laboratory of Cognitive and Behavioral Neuroscience, Graduate School of Medicine Osaka University, Health and Sport Science Building, Machikaneyama 1-17, Toyonaka, Osaka, 560-0043, Japan.
Hironobu
H
Osaki
Tomoyuki
T
Naito
Osamu
O
Sadakane
Masahiro
M
Okamoto
Hiromichi
H
Sato
D000818:Animals; D002415:Cats; D009433:Neural Inhibition / Q000502:physiology*; D009474:Neurons / Q000166:cytology / Q000502:physiology; D010775:Photic Stimulation / Q000379:methods*; D014793:Visual Cortex / Q000166:cytology / Q000502:physiology*; D014794:Visual Fields; D014795:Visual Pathways / Q000166:cytology / Q000502:physiology*