Cerebellar influence on the unitary discharge of oculomotor nuclei and adjacent structures

Abstract

The unitary discharges of mesencephalic cells located within and around the oculomotor nuclear complex were recorded, using tungsten microelectrodes in immobilized guinea pigs. The effects of electrical stimulation of different cerebellar cortical areas on these unitary discharges were investigated. About 55% of the recorded points within the oculomotor nuclei were modified by the electrical stimulation of the ansoparamedian lobe as well as the lobus medius medianus (Larsell's lobules H VII a b, VI and VII) of the cerebellum. The cerebellar stimulation provoked different patterns of activation or inhibition of the oculomotor unitary discharge. About 77% of the recorded points within the gray substance ventral to the aqueduct, the reticular substance, red nuclei and medial longitudinal fasciculus were also influenced by stimulation of the same cerebellar areas and showed similar but more evident patterns of activation or inhibition. All the recorded units located within and around the oculomotor nuclear complex were also strikingly affected by stimulation of the labyrinth. Thus both a cerebellar and vestibular influence on the units studied has been demonstrated and compared.