[Inhibition and space-frequency characteristics of the complex receptive fields of the cat visual cortex]

Responses of complex receptive fields of the cat straitum to moving sinusoidal grating were studied. Stimulation of the receptive field with some spatial frequencies suppresses spontaneous discharges. Responses of the receptive field corroborate previously made predictions that the spatial--frequency characteristics of the receptive field should have the main and the secondary maximums and negative areas in case the complex fields perform piece-wise Fourier--transformation of image. The changes of impulse frequency in field's response are predicted by comparing the changes of instantaneous spectrum of grating entering the field with spatial frequency characteristic of the field. The data evidence that the complex field is rather a spatial--frequency filter than a detector. Some complex fields reveal a lateral inhibitory area behind the field's nucleus in direction of stimulus movement. The complex fields with no lateral inhibitory areas seem to serve for piece Fourier--description of image, those with lateral areas--for picking out the countour between textures.