This MRI Planning Grant for one year is to clarify the origin of an electrical potential waveform that occurs very early in response to an auditory stimulus. In a whole range of vertebrates, there is a characteristic set of electrical potentials that characterize the response of the auditory system to a sound. A waveform is present just before the wave representing the volley in the auditory nerve, and this early wave may reflect the activity at the nerve terminals where they receive input from the receptor cells. The junction between a receptor cell and a nerve terminal is a synapse, and this early wave may represent an excitatory post-synaptic potential (EPSP), which would be the signal that excites the nerve. This planning grant will support collaboration and training for the PI in a laboratory where significant expertise is available in this area of auditory physiology. A brief comparative study will be done to try to clarify the nature of this early waveform in three different species. Pharmacological blockage studies should reveal information about the origins of the EPSP in the peripheral auditory system. The study is important to provide a basis for a future project to clarify the nature and function of the similar waveform found in humans. The comparative studies here will allow access to peripheral processes not available for study in humans.
