Neural Correlates of Streaming of Complex Sounds

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DESCRIPTION (provided by applicant): This collaborative project combines psychoacoustic and physiological investigations of a fundamental perceptual component of auditory scene analysis known as auditory streaming. This phenomenon manifests itself in the everyday ability of humans and animals to parse complex acoustic information arising from multiple sound sources into meaningful auditory "streams". For instance, the ability to listen to someone at a cocktail party or to follow a violin in the orchestra both seem to rely on the ability to form auditory streams. While seemingly effortless, the neural mechanisms underlying the ability to form auditory streams remain a mystery. Consequently, the few attempts at developing models of auditory stream segregation remain highly speculative, and lack the physiological data to support their formulations. The primary objective of the proposed research is to explore streaming of complex sounds in humans, and to investigate the neural mechanisms that underlie this ability in animals. Until recently, the investigation of the neural mechanisms of streaming in non-human species has been hampered by the difficulty of assessing subjective perceptual phenomena like streaming without relying on introspection and language. Building upon recent progress in the area, this project overcomes this difficulty by including as a key ingredient the development and usage of specially designed stimuli and psychoacoustic tasks to induce, manipulate, and objectively assess streaming in both animals and humans. Furthermore, these stimuli and tasks are designed in such a way that valuable physiological data can be collected simultaneously with task performance in animals. Furthermore, the proposed research rigorously investigates the hypothesis that streaming of a complex sound from a cluttered acoustic environment can be associated with segregation of spectral and temporal features found at a higher level of representation. Specifically, these features are inspired by physiological and psychoacoustic studies' of spectrotemporal analysis in the auditory cortex.