Grant: Project Grant

Tinnitus is a bothersome noise or ringing in the ears occurring in the absence of external auditory stimulation. It is a common problem affecting approximately 1 person in 4 in Canada and is most often linked to age-related hearing loss. In around 6% of these cases, tinnitus is so distracting that it interferes with several central aspects of their lives including sleeping and working, and in the worse cases can lead to even depression and suicide. There is currently no effective treatment for tinnitus in large part because the mechanisms causing it are mostly unknown. Aberrant rewiring of the sound processing areas of the brain is thought to play an important role in the emergence of tinnitus, but the very nature of this reorganization remains very controversial. The primary goal of this project is to, using a rodent model of the disorder, understand precisely if and how the brain is reorganized in tinnitus sufferers. We propose experiments that will make use of novel neurophysiological techniques we have developed to map the auditory cortex's functional organization using intracortical recording of individual neurons. Furthermore, we will also make use of novel chemogenetic approaches that allow us to manipulate plasticity-regulating neurons to determine whether they are dysfunctional in tinnitus. The chosen methods, all mastered by at least one member of our team, were selected to best answer our research questions and maximize the quality and quantity of the data obtained. The proposed research will shed light on some of the neural mechanisms that underlie the emergence of tinnitus. We furthermore expect that our findings will significantly enhance our understanding of the mechanisms underlying the emergence of tinnitus and will also hopefully provide new therapeutic targets for future research.