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Posteroventral cochlear nucleus projections to olivocochlear neurons
Author(s) -
Thompson Ann M.,
Thompson Glenn C.
Publication year - 1991
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.903030209
Subject(s) - superior olivary complex , efferent , brainstem , neuroscience , cochlea , trapezoid body , biology , cochlear nucleus , nucleus , anatomy , auditory system , anterograde tracing , neuron , afferent
The presence of ascending auditory inputs from the posteroventral cochlear nucleus (PVCN) to olivocochlear neurons was examined in guinea pig by using the combination Phaseolus vulgaris ‐leucoagglutinin (PHA‐L) anterograde and horseradish peroxidase (HRP) retrograde tract‐tracing technique. By labeling the somata of olivocochlear neurons after injection of HRP into the cochlea and simultaneously labeling terminal endings of PVCN efferent neurons after injection of PHA‐L into PVCN, we observed neuronal connections between these two elements within all regions of the superior olivary Complex known to contain olivocochlear neurons. These regions include the superior paraolivary nucleus, medial nucleus of the trapezoid body, lateral superior olive, and periolivary regions. All possible projection patterns regarding side of input and output of both large (four combinations) and small (two combinations) olivocochlear neurons were observed. However, the most frequently observed pattern was the PVCN projection to a contralaterally located and contralaterally projecting, large olivocochlear neuron. Thus the most prevalent pattern demonstrated a feedback pathway that crossed the brainstem twice. Additional patterns demonstrated pathways that fed back to the same cochlea as well as pathways that fed forward to the opposite cochlea.