[Truncated abstract] Spontaneous neural hyperactivity in the central auditory pathway is often associated with deafness and may be a consequence of elevation in overall excitation due to the imbalance between inhibitory and excitatory neurotransmission and/or changes in neuron membrane excitability. In this thesis, two guinea pig models of partial deafness, cochlear mechanical lesion and acoustic trauma, have been investigated. For each model, peripheral hearing loss, spontaneous activity, and mRNA abundance for 8 genes involved in neurotransmission and excitability, have been measured in the same animals and data correlated. In addition, protein abundance and distribution for one of the 8 genes, the GABA-A receptor subunit alpha, has also been studied in a different group of animals for both models, using immunocytochemistry. This thesis demonstrated dramatically elevated spontaneous firing rates across most of the frequencies in guinea pig contralateral inferior colliculus (IC) following either restricted cochlear mechanical lesion or acoustic trauma. Spontaneous activity elevation was most marked in the relatively high frequency region corresponding to that of peripheral hearing loss immediately after mechanical lesion or acoustic trauma and to the frequencies of residual hearing loss after the recovery periods. Plastic changes were found in mRNA expression of neurotransmission- and membrane excitability–related genes in both the CN and IC in response to the unilateral partial hearing loss...
|Qualification||Doctor of Philosophy|
|Publication status||Unpublished - 2009|