Cerebellar contributions to the papez circuit

AbstractCerebellar influences on the various substructures in the Papez Circuit are indicated by the following. Anatomical studies indicate that the major midbrain areas to which this circuit projects are : (1) ventral tegmental area; (2) interpeduncular area; and (3) periaquenductal gray areas; and these same areas project back to the limbic system. There are projections to these regions from the cerebellar nuclei, as indicated by terminal degeneration studies which show that cerebellar nuclei connect, mostly by fine fibers, with a continuum of cells located on either side of the midline in the ventral tegmentum of the midbrain. Observations that the cerebellum also projects to the locus ceruleus (NA system) and VTA (DA system) indicate that cerebellar influences can also reach the limbic areas via the catecholamine fiber bundles. Electrophysiological studies indicate that vermian and fastigial stimulation induce evoked responses in the basolateral amygdala, the hippocampus, and the septum, with laterncies to the peak of first wave ranging from 4 to 8 msec and to the second wave of 16–29 msec. Citations from the physiological literature indicate that electrical stimulation of the