Activity of single medial geniculate units in response to single and double clicks.

The discharge pattern to clicks and the time course and pattern of the click-induced inhibition in the medial geniculate body have been studied by single unit recording technique. The medial geniculate neurones showed a tendency to fire at preferred latencies after a click. A conditioning click caused a reduced number and increased latency of the discharges to a subsequent test click. Provided conditioning click of a certain strength was employed, the inhibition was often cyclic, each period lasting for about 100-150 ms. Clicks could also trigger barbiturate spindles with synchrony between the activity of the medial geniculate body and the primary auditory cortex. Interaction experiments suggest that the triggered and spontaneous spindle activity operate with the same neurones.