Increased synchrony and bursting of dorsal cochlear nucleus fusiform cells correlate with tinnitus

Associated faculty or student(s): Publication Date:
Wednesday, February 10, 2016

Tinnitus, the perception of phantom sounds, is thought to arise from increased neural synchrony, which facilitates perceptual binding and creates salient sensory features in the absence of physical stimuli. In the auditory cortex, increased spontaneous cross-unit synchrony and single-unitbursting are de facto physiological correlates of tinnitus. However, it is unknown whether neurons in the dorsal cochlear nucleus (DCN), the putativetinnitus-induction site, exhibit increased synchrony. Using a temporary-threshold shift model and gap-prepulse inhibition of the acoustic startle to assess tinnitus, we recorded spontaneous activity from fusiform cells, the principle neurons of the DCN, in normal hearing, tinnitus, and non-tinnitusguinea pigs. Synchrony and bursting, as well as spontaneous firing rate (SFR), correlated with behavioral evidence of tinnitus, and increasedsynchrony and bursting were associated with SFR elevation. The presence of increased synchrony and bursting in DCN fusiform cells suggests that a neural code for phantom sounds emerges in this brainstem location and likely contributes to the formation of the tinnitus percept.

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