Commissural Neurons in the Rat Ventral Cochlear Nucleus

AUTOR(ES)

Doucet, John R.

FONTE

Springer-Verlag

RESUMO

Commissural neurons connect the cochlear nucleus complexes of both ears. Previous studies have suggested that the neurons may be separated into two anatomical subtypes on the basis of percent apposition (PA); that is, the percentage of the soma apposed by synaptic terminals. The present study combined tract tracing with synaptic immunolabeling to compare the soma area, relative number, and location of Type I (low PA) and Type II (high PA) commissural neurons in the ventral cochlear nucleus (VCN) of rats. Confocal microscopic analysis revealed that 261 of 377 (69%) commissural neurons have medium-sized somata with Type I axosomatic innervation. The commissural neurons also showed distinct topographical distributions. The majority of Type I neurons were located in the small cell cap of the VCN, which serves as a nexus for regulatory pathways within the auditory brainstem. Most Type II neurons were found in the magnocellular core. This anatomical dichotomy should broaden current views on the function of the commissural pathway that stress the fast inhibitory interactions generated by Type II neurons. The more prevalent Type I neurons may underlie slow regulatory influences that enhance binaural processing or the recovery of function after injury.

Documentos Relacionados

• Ventral Cochlear Nucleus Responses to Contralateral Sound Are Mediated by Commissural and Olivocochlear Pathways
• Electrophysiological Properties of Octopus Neurons of the Cat Cochlear Nucleus: an In Vitro Study
• The caudate nucleus of the rat: cell types and the demonstration of a commissural system.
• The ventral and dorsal lateral geniculate nucleus of the rat: intracellular recordings in vitro.
• Neurones in commissural nucleus tractus solitarii required for full expression of the pulmonary C fibre reflex in rat.