Development of Objective Electrophysiological Tests for Tinnitus Based on Long-Lasting After-Discharges in the Inferior Colliculus
Technical Report,01 May 2018,30 Apr 2019
University of Connecticut FARMINGTON CT FARMINGTON United States
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Long-duration sound-evoked after-discharges LSA may be a new form of plasticity with intermediate-duration potentiation in the auditory midbrain. We studied the properties of LSA in response to different sounds of long duration. Multi-channel single shank electrodes recorded spontaneous firing before and after the presentation of a long duration sound LDS, 60s from several frequency laminae in the inferior colliculus simultaneously. LSA was defined as firing after LDS that was two standard deviations above the mean spontaneous firing rate before LDS. We found LSA in at least 23 of the recording sites. We could identify two basic response patterns immediate onset after LDS or delayed onset build-up after LDS that began as late as 20 s after the LDS offset. Both response patterns could last for over a minute. The response type, immediate vs build-up, could not be predicted by the neural response during the long duration sound. Since the observed firing after the sound offset resembles acoustically driven activity, LSA may be related to tinnitus, a disease that is defined as the perception of a sound in the absence of an external sound stimulus.
- Anatomy and Physiology