Cerebello-cerebral projections onto the ventral part of the frontal cortex of the macaque monkey.

The cerebellar projections to the ventral part of the frontal cortex were investigated in the Japanese monkey (Macaca fuscata). In anesthetized monkeys, stimulation of either the lateral or interposed cerebellar nucleus evoked marked surface-negative and depth-positive potentials in the face motor area (Mf) and the upper part of the ventral premotor area (PMv) on the contralateral side; responses were hardly recorded in the lower part of PMv including the areas related to the laryngeal movements. Stimulation of the medial cerebellar nucleus induced no significant responses in these areas. The results of the combined anterograde and retrograde tracing study indicated that the cerebellar nuclei projected to Mf and the upper part of PMv mainly through the nucleus ventralis posterior lateralis pars oralis and area X of the thalamus, respectively.