RESPONSES OF VESTIBULAR UNITS TO STIMULATION OF INDIVIDUAL SEMICIRCULAR CANALS

The convergence of influences elicited by circumscribed warming of individual semicircular canals of curarized guinea pigs was analyzed for single units in the lateral vestibular nucleus. The units responded to the labyrinthine stimulations with either activation or inhibition of the discharge rate. Of 72 units, 60 (84%) were influenced by separate stimulation of single semicircular canals of either labyrinth. The highest number (23) of units responded to all six semicircular canals, while the response of only 12 units was limited to stimulation of the canals of a single labyrinth. Facilitation of unitary discharge was the most frequent response regardless of which canal was stimulated. Thus, for the first time, single vestibular units have been demonstrated to receive converging influences from each of the six semicircular canals, stimulation of which produces nystagmus in different planes. © 1969.