Examining the effects of audiovisual associations on motion perception through task-based fMRI

Abstract

Objective: Previous studies showed that associative learning can lead to drastic changes in perceptual experience and unexpected levels of sensory plasticity in the adult brain. However, how associative learning is involved in shaping perception and the underlying neural mechanisms are quite poorly understood. In the current study, by taking advantage of well-studied visual motion-processing hierarchy, the roles of different brain areas in audiovisual association-induced changes in motion perception are investigated. Method: Using a previously developed audiovisual associative paradigm, behavioral and Blood Oxygen Level Dependent (BOLD) data were collected from adult human participants (n=13) before and after the association phase. Behavioral data were collected through reports on visual motion direction. Functional magnetic resonance imaging (fMRI) was based on block design and the functional data were analyzed according to a general linear model. Results: Audiovisual associations, acquired within a short time and without any feedback, significantly affected the perception of motion direction. This effect was much more salient when the physical direction of visual motion was ambiguous. Moreover, fMRI findings pointed out that the BOLD activities across different cortical regions changed after the associative phase. Conclusion: Taken together, these findings indicate that low-level sensory, multisensory and high-level cognitive areas play a role in the effects of audiovisual associations on motion perception. In general, this suggests that our prior experiences acquired through associations may affect perceptual processing at different hierarchical levels and over different cortical areas.