Corticopontocerebellar pathway from the prearcuate region to hemispheric lobule VII of the cerebellum: an anterograde and retrograde tracing study in the monkey.

The relationship between axons derived from the prearcuate region and pontine neurons projecting to contralateral cerebellar hemispheric lobule VII, lobulus petrosus (LP) of the paraflocculus or the dorsal paraflocculus (DPFl) was investigated in the monkey. The frontopontine axons were labeled with biotinylated dextran and pontocerebellar neurons with cholera toxin subunit B or fast blue. Labeled frontopontine axons and terminals were seen in the dorsal, medial, paramedian and dorsolateral parts of the pontine nuclei. The distribution of the labeled frontopontine axons overlapped that of labeled neurons projecting to hemispheric lobule VII but did not overlap that of labeled neurons projecting to LP or DPFl. The pathway from the prearcuate region to hemispheric lobule VII may provide an anatomical substrate for the involvement of hemispheric lobule VII in voluntary eye movements.