Schedule of Events | Symposia

Neural mechanisms of biological motion perception in deaf native signers and hearing non-signers

Poster Session F - Tuesday, April 1, 2025, 8:00 – 10:00 am EDT, Back Bay Ballroom/Republic Ballroom

Carolyn Gershman¹ (cdg60@georgetown.edu), Ted Supalla¹, Anna Seydell-Greenwald^1,2, Barbara Landau^1,3, Elissa L. Newport^1,2; ¹Center for Brain Plasticity and Recovery, Georgetown University Medical Center, ²MedStar National Rehabilitation Hospital, ³Department of Cognitive Science, Johns Hopkins University

Sign language is a visual gestural language that is expressed manually on the hands, face, and body, and mediated by movements through space. Because sign language is processed in left-dominant language networks, lifelong experience with sign language may alter the processing of non-linguistic motion stimuli. For example, some studies suggest stronger left-hemisphere involvement in coherent motion processing in deaf signers, but evidence is still limited. The processing of biological motion, which shares properties inherent to sign language, might show even stronger changes. Here, we investigated differences between 19 deaf native signers and 19 hearing controls in the fMRI activation for biological motion processing (judging the heading direction of a point-light walker) compared to coherent motion processing (judging the heading direction of a coherently random dot pattern). Both groups showed activation in ventral extrastriate cortex, bilateral MT-MST, and right pSTS. ROI analyses in MT-MST and right pSTS showed no differences in strength of activation, but deaf signers showed significantly greater activation in PT and STG regions. Lateralization in MT-MST differed between the groups, with deaf signers showing right-lateralization and hearing participants bilateral activation for biological motion processing, both relative to coherent motion processing and relative to a resting baseline. The overall activation patterns and the relative increase of activation for visual motion processing in early auditory cortex are consistent with previous studies on biological motion processing and cross-modal plasticity. However, the shift towards right-lateralized activation for biological motion processing in deaf native signers contrasts with previous reports and merits further investigation.

Topic Area: PERCEPTION & ACTION: Multisensory