Hearing in mammals depends on the reliable transmission of sound information transduced from the sensory hair cells of the cochlea to the cochlear nucleus of the brain stem via the spiral ganglion neurons. The spiral ganglion neurons (SGNs) are the only neuronal relay of sound information from the periphery to the central nervous system. The proper development and organization of the spiral ganglion is required for hearing to occur. This dissertation focuses on the developmental process of the spiral ganglion neurons. Using modern birth-dating and genetically inducible fate mapping, I clarify several features of the timing of early spiral ganglion development. Using genetically inducible fate mapping with Ngn1creERt2, I was able to confirm in clonal pairs that progenitors produce both type I and type II neurons. In the search for diversity within the spiral ganglion, I identified Pou4f1 as a potential type I SGN subtype. I found that a vast majority of Pou4f1 expressing SGNs terminate at P3 on the medial side of the inner hair cell, which may correspond to a subgroup of low spontaneous rate fibers. I demonstrate that continued expression of Pou4f1 may not necessary after E14 for neuronal survival or for the proper innervation of the organ of Corti. To further probe the diversity present within the spiral ganglion neuron population, I employed single cell RNA-sequencing techniques. I demonstrate that single cell FAC-seq is a robust method for generating single cell libraries for rare populations of cells. Using principal component analysis, I was able to identify differentially expressed genes within the spiral ganglion neurons. Ultimately, FAC-seq results show that there is a large amount of homogeneity within the spiral ganglion population.
Sherrill, Hanna Elyse,
"Developing neuronal diversity in the spiral ganglion"
(2017).
Neuroscience Theses and Dissertations.
Brown Digital Repository. Brown University Library.
https://doi.org/10.7301/Z0G73C5R
