Modulation of recurrent inhibition in cat association cortex by reticulocortical arousal

Lesion-induced degeneration and single unit techniques were used to study the effects of reticular arousal and antidromic callosal stimuli on middle suprasylvian gyrus neurons in the cat. In acute experiments done 2 weeks–6 mo after ablation of the contralateral homotypical cortex, most neurons showed inhibitory responses to 400 Hz callosal volleys. Excitatory reticular stimulation 300 msec prior to the callosal stimulus increased the duration of the antidromic callosal inhibition. An interpretation of the data is made in terms of recurrent inhibitory circuits in association cortex.