Postgraduate Profiles

Ahmaed Baashar

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Thesis: The Anatomical Relationship between Cochlear Nucleus Neurons and Collaterals of the Olivocochlear Pathway

The auditory system is composed of ascending and descending auditory pathways. The latter pathways play an important role enabling the brain to modify afferent auditory input before it reaches the cortex. An important component of the descending pathways is the olivocochlear system which originates in the brainstem and projects out to the cochlea. One subdivision of the olivocochlear system consists of the medial olivocochlear (MOC) neurons that give off collateral branches to the cochlear nucleus. Collateral branches of MOC neurons have been shown to make synaptic contacts with dendrites of multipolar, stellate, neurons in the ventral cochlear nucleus. Multipolar neurons in the ventral cochlear nucleus, however, consist of two distinct neuronal populations: T-stellate neurons projecting to the inferior colliculus and D-stellate neurons projecting to the contralateral cochlear nucleus. Each of these ventral cochlear nucleus subtypes serves a variety of roles in auditory processing. However, it is still unclear which of these neurons receive synaptic innervation from the collaterals of the MOC axon since a conflict exists in literature between results obtained from in vivo electrophysiological studies and in vitro pharmacological studies. Therefore, this project aims to identify which neural cell types in the ventral cochlear nucleus (T-stellate and/or D-stealte) receive synaptic innervation from the collaterals of MOC neurons using anatomical techniques.

Why my research is important

This research is necessary to shed light on the possible role of the olivocochlear collaterals in auditory processing by knowing which cell types in the ventral cochlear nucleus receives synaptic innervation from the collaterals of MOC neurons.

Funding

Jul 2012

Jul 2016

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