Auditory streaming as a paradigm of synergetic pattern formation in brain and behavior

Abstract

Synergetics has established a well-known top-down approach to the modeling of perceptual phenomena in psychology and cognitive sciences. This phenomenological approach is deply rooted in the theory of pattern formation and offers a formal justification that in the proximity of transitions from one pattern to another a low-dimensional description via canonical models is permissible. We exploit this thinking in the context of auditory scene analysis, specifically auditory streaming, where the brain network integrates or segregates sounds that arise from two or more distinct sources. We interpret the process of integration and segregation as a pattern formation process and demonstrate through mathematical modeling, behavioral experiments and functional magnetic resonance imaging (fMRI) that selected networks in the brain get differentially activated as a function of the percept. We propose a functional architeture composed of brain areas with tonotopic organization (auditory cortex) and non-tonotopic organization (various parietal areas including right superior parietal lobule and precuneus). The dynamics of this functional architecture extends beyond auditory streaming and suggests the existence of informational convergence zones in the brain that get selectively activated in a nonlinear all-or-none fashion. This dynamics is reminiscent of phase transitions as discussed in synergetics and generalizes concepts well established in multisensory integration.