Thesis

Trauma-induced tonotopic reorganisation in rat auditory cortex

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Awarding institution
  • University of Strathclyde
Date of award
  • 2015
Thesis identifier
  • T13955
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Department, School or Faculty
Abstract
  • Tinnitus is one of the most common auditory disorders and can be characterised as the conscious perception of sound with no physical external source. There is no cure for tinnitus and no definitive answer to its cause which is why developing a reliable animal model could advance research in this field. Hearing loss has been demonstrated to play a significant role in the generation of the tinnitus percept. The most common precursors for tinnitus are through noise induced hearing loss which results in permanent and neuroplastic changes in the central nervous system. We tested the hypothesis that due to the damage to the cochlear structure could lead to reorganisation of the frequency specific tonotopic map in the primary auditory cortex. To this end, in vivo electrophysiology using a 32 channel 8 shank silicon tetrode was adopted to investigate the changes in frequency responsive areas in the primary auditory cortex following acoustic trauma in Spargue-Dawley rats. Neuronal recordings were taken prior and directly after acoustic trauma stimulus and used 225 short pip combinations of varying frequencies (2-32 kHz) and intensities (0-80 dB SPL). Then three acoustic trauma stimuli were played for one hour; no sound, 104 dB SPL broadband white noise and 16 kHz pure tones at 82.5dB SPL. From the silence experiment, the presence of the tonotopic map was confirmed. In the 104 dB white noise acoustic trauma experiment there was no evidence of neural thresholds increasing which was predicted. The 16 kHz pure tones 82.5 dB SPL showed an increase in neural thresholds at one of the positions in the auditory cortex. Further optimisation is required before a conclusion can be stated to determine the changes in tonotopic organisation in the auditory cortex following acoustic trauma.
Resource Type
DOI
Date Created
  • 2015
Former identifier
  • 1217348

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