CAREER: Dynamics of Audition: Rhythm, Music, and Attending

Florida Atlantic University, Boca Raton FL

Investigators

Abstract

What does the neural representation of a complex, temporally structured auditory event look like? When we listen to a symphony or a speech, what neural processes allow us to maintain a stable attentional focus? How do the requisite auditory representations form, how do they adapt to unexpected nuances, and how do they reorganize to accommodate structural change? This research will test a theory of auditory perception and attention that focuses on complex, temporally structured events, such as speech and music. The theory holds that the mental representation of an auditory event is a self-organized, dynamic structure whose neural correlate is a spatiotemporal pattern of neural activity. The primary function of this hypothesized spatiotemporal structure is attentional: it enables anticipation of future events and thus the targeting of perception and the coordination of action with external events. The stability and flexibility properties of attention in this theory both arise through nonlinearities in the underlying pattern-forming dynamics. Furthermore, the hypothesized dynamic representations in the theory function in auditory communication. It is known empirically that transient stimulus fluctuations, such as intonation and rate changes observed in both speech and musical performance, communicate intention, emotion, and structural information. The theory holds that these communicative gestures are recognized as deviations from temporal expectations embodied in the attentional structure. This theory explains how people maintain a stable attentional focus over temporally extended events while adapting flexibly to transient temporal fluctuations. It provides mathematical models of dynamic structural representation, using the tools of nonlinear dynamical systems. It makes predictions about neural correlates of auditory representation, attention, and communication. Finally, it applies to complex, temporally structured event sequences, explaining how people respond to the auditory complexity of the real world. The experiments will use music, as well as simpler music-like sequences, to model temporally extended events. Theoretical predictions will be tested using behavioral and neuroimaging techniques. Behavioral experiments will assess predictions in four areas 1) formation and stability of structural representations, 2) real-time tracking of temporally structured sequences, 3) the role of rhythm in attention, and 4) the role of expectancy in auditory communication. Neuroimaging techniques (EEG, MEG) will measure temporal and spatial aspects of neural function in auditory perception and attention, to further assess theoretical predictions. Modifications to the theory will be based on comparison of experimental results with predictions of computer simulations, and extensions to the general theory will be developed. This research will advance our basic understanding of auditory perception and attention by enhancing our knowledge of the role of structure in perceiving and attending to complex events. The results have potentially wide applicability from the development of more robust computer algorithms for speech recognition and music processing, to deeper clinical understanding of recovery from neural trauma, such as aphasic stroke.