Sensorimotor simulation and distributed processing of biological motion: Insights from healthy and paraplegic adults

The processing of biological motion (BM), particularly the local motion cues tracing the movements of crucial joints, is vital for social interaction and human survival. While numerous studies have focused on the brain mechanisms underlying BM processing, the contribution of sensorimotor simulation at peripheral effectors remains unclear. In this study, we examined healthy adults and paraplegic spinal cord injury participants to investigate this issue. For healthy adults, both intact BM stimuli and local BM cues without global configuration induced a temporal dilation effect when sitting (sensorimotor simulation accessible), but not when standing (sensorimotor simulation temporarily hindered). In contrast, for participants with permanently hindered sensorimotor simulation, the temporal dilation effect was observed only with intact BM stimuli but not with local BM cues, indicating a robust reliance on sensorimotor simulation during the processing of local BM cues and a selective compensation based on global configuration cues for the permanent loss of sensorimotor simulation. These findings highlight the role of embodied cognition in the distributed processing of biological motion and suggest the importance of selective compensation under damaged sensorimotor circuits.