Termination in posterior and anterior cerebellum of a climbing fibre pathway activated from the nucleus of Darkschewitsch in the cat.

Climbing fibre projections to the C2 zone of the cerebellar cortex activated from structures in the midbrain were studied by electrophysiological technique in chloralose-anaesthetized cats. The C2 zone was identified in the paramedian lobule and in the intermediate part of the anterior lobe by peripheral nerve stimulation. Foci in the medial midbrain, which upon low intensity stimulation selectively evoked climbing fibre responses in the C2 zone, were localized by careful mapping procedures. Histologically the active region was identified as overlying the nucleus of Darkschewitsch, and it was suggested that this nucleus was the origin of a pathway which via the rostral parts of the medial accessory olive projected to the C2 zone of the posterior as well as the anterior cerebellar cortex.