[Evoked activity of cat association cortex neurons in different sleep stages].

Evoked activity of neurons in the parietal associative cortex in response to adequate and electric stimulations of the thalamic radiation fibers was studied during different phases of sleep. The number of responding neurons decreased during slow--wave and, particularly, during paradoxical sleep. With transition from phase to phase, responsiveness changed mainly in polysensory neurons which gave variable responses with long latencies. Mechanisms of change of responsiveness during the two phases appear to be different. Reliable increase of the inhibitory pause in responses during slow-wave sleep and its decrease during paradoxical sleep may indicate a strengthening of mechanisms of reciprocal inhibition during the first phase, and their weakening during the second phase.