Microcircuits of the Ventral Cochlear Nucleus

Abstract

The neurons of the cochlear nuclei are the first central processors of auditory information, and they provide inputs to all the major brainstem and midbrain auditory nuclei. The ventral region of the cochlear nucleus (the ventral cochlear nucleus) represents the beginning of the binaural pathway through its projections to the superior olivary complex. The synaptic circuitry of the ventral cochlear nucleus specializes in the precise and rapid representation of incoming signals from the cochlear afferents. The ventral cochlear nucleus has two main regions: the core or magnocellular region and the granular cell domain. The magnocellular region contains these main neuronal cell types: the bushy cells (spherical and globular) and the multipolar or stellate cells (T stellate and D stellate). Auditory nerve fibers are the major source of excitation to both bushy and stellate cells. The synaptic connectivity pattern of neural networks between the neurons in a brain region is an essential determinant of their role in information processing. This chapter concentrates on the connectivity and synaptic microcircuits, including the key molecular synaptic components that allow the principal cells (bushy and stellate cells) to accomplish their functions. In addition, putative aspects of experience-dependent plasticity and hearing loss are discussed.