Ascending connections of the anterior ventral cochlear nucleus in the rat

Abstract

Abstract The purpose of the experiment was to determine the connections of the three regions of the anterior ventral cochlear nucleus in the rat. Lesions were placed in the regions of the nucleus in 11 rats. After 25 days each animal was sacrificed and its brain impregnated by the protargol method of Bodian. The superior olivary complex, the lateral lemniscus and the dorsal acoustic stria were examined for diminution of synaptic endings, thinning of neuropil and debris of degeneration. Complete destruction of region III of the anterior ventral cochlear nucleus produced degeneration in the ipsilateral lateral superior olive and in the medial superior olive of both sides. Destruction of other regions of the anterior ventral cochlear nucleus, region III remaining intact, had no effect upon the lateral or medial superior olive. Destruction of region II of the anterior ventral cochlear nucleus produced degeneration in the anterior halves of the ipsilateral lateral nucleus of the trapezoid body and the contralateral medial nucleus of the trapezoid body. Complete destruction of other regions of the anterior ventral cochlear nucleus, region II remaining intact, was without effect upon the lateral and medial nuclei of the trapezoid body. No degeneration was detected following destruction of region I of the anterior ventral cochlear nucleus.