Afferent projection from the dorsal nucleus of the raphe to the flocculus in cats.

Horseradish peroxidase (HRP) was injected iontophoretically into the cerebellar flocculus in cats. The neurons labeled with HRP were recognized in the caudal part of the dorsal nucleus of the raphe. Electrical stimulation of this region elicited orthodromic evoked potentials in the flocculus and stimulated sites of low threshold current necessary to evoke the responses were limited in a small area corresponding well with the dorsal nucleus of the raphe.