Organization of Vestibular Afferents to the Vestibular Nuclei of the Dogfish

Electrophysiological and light microscopical studies were made on the vestibular area of the dogfish hindbrain. Three vestibular nuclei were distinguished: the superior nucleus (VES), the magnocellularis nucleus (VEM), and the ventral nucleus (VEV). The distribution of field potentials evoked in the hindbrain by stimulation of nerve VIII confirms the location and extent of the vestibular nuclei. It also raises the possibility of a direct contralateral projection of vestibular nerve fibres. Unit studies confirm the interpretation of the field potentials and provide evidence of mono- and polysynaptic activation of vestibular nuclear neurons by vestibular afferents.