Gap-induced reductions of evoked potentials in the auditory cortex: a possible objective marker for the presence of tinnitus.

Gap-induced reductions of evoked potentials in the auditory cortex: a possible objective marker for the presence of tinnitus. Brain Res. 2017 Nov 27;: Authors: Berger JI, Owen W, Wilson CA, Hockley A, Coomber B, Palmer AR, Wallace MN Abstract Animal models of tinnitus are essential for determining the underlying mechanisms and testing pharmacotherapies. However, there is doubt over the validity of current behavioural methods for detecting tinnitus. Here, we applied a stimulus paradigm widely used in a behavioural test (gap-induced inhibition of the acoustic startle reflex GPIAS) while recording from the auditory cortex, and showed neural response changes that mirror those found in the behavioural tests. We implanted guinea pigs (GPs) with electrocorticographic (ECoG) arrays and recorded baseline auditory cortical responses to a startling stimulus. When a gap was inserted in otherwise continuous background noise prior to the startling stimulus, there was a clear reduction in the subsequent evoked response (termed gap-induced reductions in evoked potentials; GIREP), suggestive of a neural analogue of the GPIAS test. We then unilaterally exposed guinea pigs to narrowband noise (left ear; 8-10 kHz; 1 hour) at one of two different sound levels - either 105 dB SPL or 120 dB SPL - and recorded the same responses seven-to-ten weeks following the noise exposure. Significant deficits in GIREP were observed for all areas of the auditory cortex ...
Source: Brain Research - Category: Neurology Authors: Tags: Brain Res Source Type: research