Neural correlates of short-term adaptation processes and perceptual learning in the higher auditory system in complex listening situations during simultaneous acquisition of behavioural measures.

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Deficits in understanding speech in complex listening situations is one of the most important consequences of hearing loss. According to a 2006 report commissioned by Hear-it AISBL, 16% of all adult Europeans, i.e., more than 71 million people, suffer from a hearing loss greater than 25 dB, the definition of hearing loss recognised by the World Health Organisation. Hearing prostheses (HP) such as hearing aids and cochlear implants can help to restore the hearing with moderate to profound hearing loss. However, despite over 100 years of advances in HP technology the performance of HP users is still poor in complex listening situations. To be able to improve the design of HP, a deeper understanding of the auditory system and its adaptation mechanisms in dynamic and complex acoustic environments is needed. The proposed project aims to advance the understanding of how stimulus context and perceptual learning influence the functional organization of the mature brain. Previous findings on the processing of harmonic complex stimuli in the auditory system will be used for the first time to evaluate such short-term adaptation and plastic reorganization during perceptual learning in the auditory system of the mature brain. Therefore, key objectives of the proposed project are to identify mechanisms by which neurons in higher levels of the auditory system rapidly adapt their neuronal responses to dynamically changing complex stimuli and to investigate long-term changes in the neuronal response pattern and their specificity while learning an auditory detection task using harmonic complex stimuli. The novel approach of simultaneously recording neuronal responses with chronic electrode implants from awake and behaving animals will be applied which allows the direct correlation of neuronal response patterns to perceptual behaviour.