Projections of Characterized Trapezoid Body Axons

点击翻译按钮获取中文摘要

Auditory information is first processed in the brainstem by neurons in the cochlear nuclear complex, containing several cell types. Output axons of many of these cells project forward in a major pathway forming a structure called the trapezoid body (from its shape). These axons then terminate on neurons at the next higher level called the superior olivary complex. We do not yet understand how the signals from the cochlear nuclei are related to higher aspects of auditory function, such as sound localization or startle responses, which are handled by neurons in the superior olive. This project will determine the signalling and target destinations of the these trapezoid body axons. Intracellular recordings will be used to physiologically characterize the response properties of single axons that extend into the trapezoid body, and intracellular dye filling then will be used to trace the pathways, from cells of origin to target cells, within the cat brainstem. Light and electron microscopy will provide details of location of terminals for each cell, and of detailed morphology of the synaptic endings, to morphologically characterize cell types. This classification then will be correlated to the observed functional responses of these cells. This work will provide a unique integration of information in the central auditory pathway; it will clarify what kinds of signal processing occur at the important level connecting the cochlear nuclei to the superior olivary complex, and will clarify the functional significance of morphological cell classification in the cochlear nucleus.