Rhythmical Cerebellar Responses to Labyrinthine Stimulation

Abstract

The electrical activity of the cerebellar cortex has been recorded with microelectrodes simultaneously with the action potentials of a few fibers of an oculomotor nerve during eye nystagmus brought about by thermic stimulation of the labyrinth in curarized guinea pigs. Tonic and rhythmical responses to the labyrinthine stimulation were recorded from uvula, flocculus and paraflocculus. Rhythmical cerebellar response:; in 81% of the cases exhibited the same frequency as that of the eye nystagmus. However, in the great majority of cases the rhythmical cerebellar outbursts were not perfectly synchronous with the quick or slow phases of the eye nystagmus. In the remaining 19% of cases the frequency of the rhythmical cerebellar responses was different from that of the eye nystagmus. The conclusion may be reached that the cerebellum although not essential for the appearance of the eye nystagmus is the seat of rhythmical activity during eye nystagmus. Thus the cerebellum utilizes messages from the vestibular apparatus in order to influence and regulate the correct performance of the extra-ocular movements just as it acts on the limb movements.