DIRECT PROJECTIONS FROM THE MEDIAL VESTIBULAR NUCLEUS TO THE POSTERIOR HYPOTHALAMIC AREA IN THE MONKEY (MACACA-FUSCATA)

Direct projections from the medial vestibular nucleus to the posterior hypothalamic area was found in the macaque monkey by the anterograde and the retrograde tract-tracing methods. After injection of biotinyla ted dextran amine (BDA) into the ventrolateral part of the medial vest ibular nucleus, anterogradely labeled axon terminals were seen bilater ally in the posterior hypothalamic area. After injection of wheat germ agglutinin-conjugated horseradish peroxidase (WGA-HRP)into the poster ior hypothalamic area, retrogradely labeled neuronal cell bodies were observed bilaterally in the ventral part of the medial vestibular nucl eus with a contralateral predominance.