Poster A107, Saturday, March 25, 5:00 – 7:00 pm, Pacific Concourse
A Causal Study of the Role of Motor Planning in Musical Beat Perception
Jessica Ross1, John Iversen2, Ramesh Balasubramaniam1; 1University of California, Merced, 2University of California, San Diego
It has been suggested that the motor system plays an essential role in the perception of musical rhythms. The Action Simulation for Auditory Prediction (ASAP) hypothesis proposes that the dorsal auditory stream is involved in bidirectional interchange between beat-based prediction in motor planning regions and auditory perception via parietal cortex (Patel & Iversen, 2014). We used a transcranial magnetic stimulation protocol, continuous theta burst stimulation (cTBS), that is known to down-regulate cortical activity for up to 60 minutes following stimulation, to test for causal premotor contributions to musical beat perception. cTBS target areas included posterior parietal cortex (PPC), which is part of the dorsal auditory stream, and supplementary motor area (SMA). We hypothesized that down-regulating PPC would interfere with accurate beat perception by disrupting auditory-premotor connections, while not interfering with non-predictive timing abilities. We predicted that down-regulating SMA, which is not part of the dorsal auditory stream but implicated in internally generated movements, would also interfere with accurate beat perception. Our preliminary data (n=7) suggest that down-regulating PPC raises accurate beat perception detection thresholds by 33% compared with no change after sham stimulation. We found that other timing abilities (interval perception and isochrony detection) were not impacted by cTBS to PPC or SMA. These results support that the dorsal auditory stream may play an essential role in accurate rhythm perception, but not in non-predictive timing.
Topic Area: PERCEPTION & ACTION: Motor control