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Fishes inhabit incredibly cacophonous environments and experience functional, morphological, and transcriptional auditory system plasticity in reproductive state-dependent and auditory experiential contexts. In contrast to the comprehensive study of acoustic overexposure and functional reproductive condition-dependent plasticity within the auditory periphery, the mechanisms underlying acoustic experience-mediated central nervous system plasticity in fishes are generally poorly characterized. Recent research has highlighted neurochemical and transcriptional flexibility within the central nervous systems of fishes in response to prolonged exposure to music. However, the contributions of the acoustic characteristics of musical stimulation to central nervous system plasticity remain unclear. To evaluate the contributions of sound stimulus frequency to brain plasticity, I employed a targeted transcriptional analysis of neuroplasticity-associated genes within the brain of zebrafish (Danio rerio) exposed to 100 Hz and 800 Hz continuous pure tones at a sound pressure level of 140 dB (re 1 μPa) for 1-week intervals across a 4-week period. The transcription of genes involved in mediating connective plasticity fluctuated as a function of duration and frequency of sound exposure, while cellular proliferation did not show variation with sound treatment; suggesting prolonged tonal stimulation may facilitate connective plasticity within the zebrafish brain. These results provide evidence of central nervous system plasticity in response to pure tone exposure and implicate sound-induced behaviour and multisensory inputs in the mediation of sound-induced transcriptional flexibility within the zebrafish brain. Collectively, this thesis highlights the complexity of auditory system plasticity and emphasizes the value of investigating acoustic experience-mediated nervous system plasticity beyond the auditory periphery in fishes.
Macksoud, Melissa, "Plasticity within the Auditory Systems of Fishes" (2019). Electronic Theses and Dissertations. 7718.