Rostral Projection Pathway of the Vestibular System

Abstract

Stimulation of the exposed vestibular nerve in cats evoked potentials in a rostrally projected system of fibers which ends in the vestibular area of the cerebral cortex. Examination of the pathway by needle electrodes revealed that there is no crossing of impulses between vestibular nuclei of the 2 sides. The rostral pathway consists of a sparse group of fibers which cross the midline at the trapezoid and end in the thalamus adjacent to the medial geniculate body, and between this nuclear mass and the posterolateral ventral nucleus. The fibers reach this point through a tract which lies between the medial and lateral lemnisci. Third order neurons extend from the nuclear relay to the posterior bank of the anterior suprasylvian gyrus. No evidence of bilateral projection was found. Although the vestibular projection pathway is anatomically closely associated with the auditory, there are no vestibular connections with the inferior colliculus.