Interaction of Two Somesthetic Areas in the Cerebellum of the Cat

Abstract

Interaction of the corebellar anterior lobe and paramedian lobule somesthetic areas were investigated by electroanatomical and electrophysiological methods. Interruption of the intracerebellar connection between these somesthetic areas and topical application of 1% lidocaine to the anterior lobe forelimb area, resulted in a partial depression of evoked responses in the paramedirn lobule forelimb area. After bilateral cerebellar pedunculotomy, antidromic and postsynaptic responses were obtained in the paramedian lobule following ipsilateral anterior lobe stimulation.
Summation of responses was observed in the paramedian lobule and interpositus nucleus following combined ferelimb nerve and anterior lobe stimulation, while a weak inhibitory effect was noted in the paramedian lobule responses after forelimb nerve and interpositus nucleus stimulation. Microelectrode recordings revealed that unitary discharges of the interpositus nucleus neuron were inhibited for 27 msec following anterior lobe stimulation, but no such effect was observed following forelimb nerve stimulation.
It appeared that, in addition to the connections due to bifurcation of the cerebellopetal fibers, there are cortico-cortical and cortico-nucleo-cortical connections between the anterior lobe and paramedian lobule somesthetic areas, and that reactional interference occurred within these areas.