Types Of Neuronal Activity In The Inferior Vestibular Nucleus

Abstract

Activity of 150 single units in the inferior vestibular nucleus was studied and neurons were classified according to their response. The response of neurons to a constant horizontal angular acceleration and deceleration of 4°/sec² revealed that 40.7% of those found did not respond to this stimulus. These were termed type V neurons and may represent projections onto the inferior vestibular nucleus mainly from the otolith organs. Type I (29.3%) neurons appear to be directly connected to the primary vestibular fibers innervating the horizontal semicircular ducts, and type II (27.3%) neurons are most likely projections onto the nucleus from the horizontal semicircular ducts via commissural pathway. Only one type III neuron and three type IV neurons were found. The former are likely related to the efferent system and the latter to multisensory integration. The number of these two types is far fewer in this nucleus than the medial nucleus.