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Hearing & Donuts (Brains and Bagels) Seminar
October 13 @ 8:30 am - 9:30 am
Title: Mechanisms of rapid action potential firing in the auditory brainstem
Jason Sanchez (NWU)
Brief description: Auditory brainstem neurons of all vertebrates fire phase-locked action potentials (APs) at high-rates with remarkable fidelity, a process controlled by specialized anatomical and biophysical properties. This is especially true in the avian cochlear nucleus magnocellularis (NM) – the analog of the mammalian anteroventral cochlear nucleus. In addition to high-voltage activate potassium (K+HVA) channels, we report using whole cell electrophysiology and modeling that resurgent sodium current (INaR) of sodium channels (NaV) is equally important and operates synergistically with K+HVA channels to enable rapid AP firing in NM. Anatomically, we detected strong NaV1.6 expression at hearing maturation, which was less distinct during hearing development despite functional evidence of INaR, suggesting that multiple NaV channel subtypes may contribute to INaR. We conclude that INaR plays an important role in regulating rapid AP firing for NM neurons, a property that may be evolutionarily conserved for functions related to similar avian and mammalian hearing.