Vestibular Evoked Potentials in Thalamus and Basal Ganglia of the Squirrel Monkey (Saimiri Sciureus)

Abstract

In anesthetized squirrel monkeys vestibular representation in the thalamus and basal ganglia was determined by field potential recording using peripheral electrical vestibular nerve stimulation. Vestibular thalamic regions were investigated for cortical connections. Two relatively large thalamic areas, nucleus ventralis posterolateralis, VPL and the posterior nuclear group (Po) received vestibular inputs with short latencies suggesting direct connections with the vestibular nuclei. Antidromic stimulation of the area 3a vestibular field did not produce responses in any of the vestibular thalamic fields. The vestibular regions in VPL and Po can be antidromically invaded from SI and the anterior parietal lobe respectively. In the striatum vestibular fields were found in the suprathalamic portion of the nucleus caudatus and dorsomedially in the putamen.