Stimulus-specific mechanical adaptation in the inner ear during repetitive sound stimulation

点击翻译按钮获取中文摘要

The term ‘Stimulus specific adaptation’ (SSA) addresses neuronal mechanisms of novelty detection in the central auditory system. The response strength of individual auditory neurons in cortex can depend on the probability of occurrence of the evoking stimulus. In this regard, ‘deviant’ stimulus frequencies that are only rarely presented can evoke larger spike activity than more often presented ‘standard’ stimulus frequencies. It also has been shown that a descending efferent projection from the cortex is involved in frequency related SSA found in auditory thalamus or inferior colliculus. In the cochlea, adaptation-like phenomena on the level of hair cell activity and otoacoustic emissions have been investigated, in particular concerning the role of the efferent olivocochlear projections. So far, the possible relation or contribution of cochlear adaptation to central auditory SSA has not been studied. The present projects wants to fill this gap. We developed a paradigm to measure frequency specific adaptation of distortion-product-otoacoustic emissions (DPOAE). We will quantify components of SSA in DPOAEs and study the contribution of efferent activity by concomitant contralateral acoustic stimulation. We also will assess if cochlear SSA depends on the behavioural relevance of certain stimulus frequencies that are used for communication or for active echolocation in awake bats.