ABSTRACT
About 55% of the cells in the cat lateral suprasylvian area were truly direction-sensitive to moving light and dark spots. For these cells the preferred direction of stimulus movement was the same for the light and dark spots. The most significant effects of the reversal of stimulus contrast was a change in the strength of the responses. A population of "dark-sensitive" neutrons was found that responded vigorously to the movement of dark spots but only very weakly to the movement of light spots. These neurons were only weakly sensitive to stationary flashing lights and responded with On/Off discharges over the whole of their receptive fields.
Subject(s)
Cerebral Cortex/physiology , Motion Perception/physiology , Neurons/physiology , Action Potentials , Animals , Cats , Cerebral Cortex/cytology , Darkness , Photic StimulationABSTRACT
Visually sensitive neurons of the lateral suprasylvian area were investigated in cats with pretrigeminal brain stem sections. Nearly 25% of a neuron population responding to the visual stimuli revealed great sensitivity to movement of black stimuli across their receptive fields. These neurons were called "black-sensitive". As a rule, they had either a low-level or no background activity. Nearly 89% of these neurons revealed direction-selective properties. The most characteristic feature of "black-sensitive" neurons was a change in response patterns with the reversion of the stimulus contrast.
