Research involves the study of neurons and hair cells (the sensory cells we use for hearing) including the spiral ganglion neuron (SGN). The first neuron in our ascending auditory pathway, the SGN connects an inner hair cell, which has converted a sound wave into an electrical signal, to our cochlear nucleus.

It's well known that the SGN performs a rate-encoding of the sound intensity within a frequency band, typically varying from 20 to 250 spikes/second, depending on the loudness of the tone. At the present, though, the cell is thought to simply relay and rate-encode an already amplified signal from the cochlear amplifier out in the hair cells. However, the neuron contains an unusual H current which I hypothesize is turned on by efferent feedback from the brain. When it's on, I believe that the neuron will become unstable and oscillate. In this state, it should amplify synaptic input from a hair cell that's within a narrow frequency band around its spontaneous oscillation frequency. Essentially, I'm investigating whether the SGN can be turned on as a lock-in amplifier.

For more information, please contact Dr. Mark Ospeck at mospeck@memphis.edu or 901.678.1668.

Above: Dr. Mark Ospeck working in the University of Memphis Integrated Microscopy Center (IMC).