Hearing Loss and Cognition: Using Behavioural Paradigms to Uncover the Learning Strategy Changes Following Noise-Induced Hearing Loss in Rodents
Abstract
Hearing loss is one of the most prevalent chronic health conditions affecting Canadians, with excessive exposure to loud noise contributing to this burden. Recent epidemiological studies have identified that hearing loss is a major risk factor for cognitive decline, and preclinical studies have identified that the hippocampus, prefrontal cortex, and striatum are sensitive to noise exposure. However, it is unclear if noise-induced changes in these brain regions ultimately affects how animals learn to perform complex cognitive tasks. In this thesis, I investigated the relationship between noise-induced hearing loss and the learning strategies underlying successful performance of cognitive tasks (i.e., assays of spatial working and reference memory, spatial learning, and pattern separation) by noise/sham exposing rats and assessing their hearing sensitivity before and after behavioural testing. Overall, my results suggest that noise exposure conferred an advantage in some rats by causing learning strategies to rely on egocentric (e.g., striatal-dependent) cues.