Bidirectional neuronal connections between the cerebellar interpositus nucleus and the brainstem (an autoradiographic study).

Ortho- and retrograde axonal labelings were demonstrated in several brainstem nuclei of cat after [3H]-leucine and [3H]-lysine microinjections into the cerebellar interpositus nucleus. Retrogradely labeled perikarya in the lateral reticular and solitary tract nuclei, locus coeruleus, substantia nigra and the raphe nuclei (midbrain raphe, dorsal, pontine and magnus) indicate the existence of possible aminergic afferents to the interpositus nucleus. The anterograde labeling of the neuropil in the above brainstem regions suggests the termination of axons or axon-collaterals originating from the interpositus nucleus.