[Structure of the receptive fields of cat pulvinar neurons sensitive to photic stimulation].

The structure of receptive fields of 262 neurons was studied in pulvinar. Of 262 neurons 142 were investigated in detail for receptive fields using stationary and dynamic visual stimuli. The receptive fields were classified into 6 groups according to the responses to the stationary light stimuli. The first group contained on-off receptive fields (44 of 142), all the investigated parts of which produced on-off responses to the flashing light spot. The second group (42 of 142) included neurons with the off-reactions from the whole surface of the receptive field. The third group comprised the on-receptive fields (19 of 142). Eight receptive fields (the fourth group) were similar to the "simple fields" of primary visual cortex. The fifth group (10 of 142 neurons) was characterized as concentric having on-off centre and on or off surrounding. The sixth group (19 of 142) included receptive fields with multiple discharge centres, the receptive field surface having silent zones for both on- and off-responses. The neurons having such receptive fields responded by multimodaly distributed discharges during the stimulation by moving and stationary visual stimuli. The average latency of responses of most neurons in pulvinar was 40-70 ms, some neurons displaying shorter (20 ms) and some longer (130-160 ms) latencies.