Top-down control during selective listening in cocktail party situations

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In daily life, listeners are often confronted with complex auditory environments consisting of multiple independent sound streams. Selectively listening to one of these streams, while not being distracted by the competing auditory stimulation, represents an ultimate challenge for our auditory system. Previous work has compellingly demonstrated that attentional filtering of information occurs at different levels of sensory processing within the auditory system, leading to both an increased auditory cortex representation of the attended stream and a suppression of irrelevant information. The ability to voluntarily control the focus of attention and to listen selectively to any sound source of interest has been linked to neural activity in a network of frontal and parietal brain regions. How these two processing levels interact during selective listening is however not fully understood. During my proposed research stay in the lab of Dr. Robert Zatorre in Montreal, Canada, I will therefore investigate the relationship between attentional gating of information in auditory cortex and goal-directed top-down control exerted by the fronto-parietal attention network during selective listening. Magnetoencephalography (MEG) will be used to measure cortical activity during a selective listening task in normal listeners as well as in a group of highly trained professional musicians. The data will be analyzed both on group-level and using performance-based between-subject approaches to identify those brain regions and functional connections essential for successful selective listening in challenging situations. In a second step, structural markers of superior selective listening abilities will be investigated using high resolution structural magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI).