Differential distribution of voltage-gated ion channels in spiral ganglion neurons

The primary sensory neurons of the mammalian auditory system are composed of a diverse population of cells with multiple types of voltage-gated ion channels. Analysis of the heterogeneity of current phenotypes has introduced a number of questions about the function of spiral ganglion neurons in neural encoding. If spiral ganglion neurons are simply conductors of peripheral auditory information, why is there such diversity in their electrophysiological properties? Is there a differential distribution of specific types of ion channels, and are they located along the apical/basal length of the cochlea that corresponds to its frequency gradients? A specific aim of my dissertation project was to study the expression of ion channel subunit proteins within of the spiral ganglion and create an immunohistochemical “map” of channel distributions along the length of the cochlea. Additionally, I investigated the regulation of ion channel proteins by the two neurotrophins present in the cochlea, BDNF and NT-3. The results obtained have given valuable insight into the functional properties of Kv1. 1, Kv3.1, Kv4.2 and K _Ca channels and help elucidate the role of spiral ganglion neurons in sound processing.