Neurophysiological and simulation studies of striate cortex receptive field maps: the role of intracortical interneuronal interactions.

Acute experiments on 27 adult anesthetized and immobilized cats investigated 101 on and off receptive fields in 67 neurons in visual cortex field 17 by mapping using single local stimuli presented sequentially at different parts of the visual field, as well as in combination with additional stimulation of the center of the receptive field. Both classical and combined mapping identified receptive fields with single receptive zones (63.4% and 29.3% respectively), along with fields consisting of several (2-5) excitatory and/or inhibitory zones (36.6% and 70.7%). We provide the first report of receptive fields with horseshoe, cross, and T shapes. Simulations of horizontal interneuronal interactions in the visual cortex responsible for the multiplicity of excitatory and inhibitory zones of receptive fields were performed. A role for cooperative interactions of neurons in this effect was demonstrated. The possible functional role of receptive fields of different types in extracting the features of visual images is discussed.