Date of Award

Fall 2014

First Advisor

Dr. Helen Murphy

Abstract

The dorsal cochlear nucleus (DCN) is a multimodal processing station found at the junction of the auditory nerve and brainstem medulla. Tinnitus-induced neuronal hyperactivity has been observed in the DCN and, thus, suggested to be the lowest region of the auditory nerve with such hyperactivity. The main integrative units of the DCN are the fusiform cells, receiving and processing inputs from auditory sources before transmitting information to higher auditory pathways. Neural hyperactivity is induced in fusiform cells of the DCN following intense sound exposure. Researchers suggest that fusiform cells may be implicated as major generators of noise-induced tinnitus. Despite previous research in describing fusiform cells and pharmacological identity of their synaptic inputs, information on their three-dimensional organization and ultrastructure is incomplete. This information is fundamental for the understanding of the normal characteristics of synapses on fusiform cells, synaptic plasticity and remodeling in hearing disorders, such as tinnitus. In this research study, serial block face scanning electron microscopy (SBFSEM) was used, followed by 3D reconstructions to quantitatively characterize and analyze the synaptic features on DCN fusiform cells. The results illustrate dense distribution of synapses and mitochondria on apical dendrites of fusiform cells.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.

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