Frequency tagging in the sensorimotor cortex is enhanced by auditory compared to visual body movement information in a walking movement integration task

Body movements like walking can synchronize with auditory and visual inputs presented within a periodic frequency range, peaking around 2 Hz. The EEG frequency-tagging approach allows to capture the synchronization of beat perception with neural brain oscillations at the beat frequency. This study used EEG frequency-tagging to explore brain dynamics during rhythmic sensorimotor synchronization with auditory (footstep sound) and visual (walking point-light figure) inputs. Sensory inputs were delivered at different rates (1 Hz, 2 Hz, 3.6 Hz) in rhythmic or random sequences while recording EEG activity. The experiment included three conditions: (i) Auditory, (ii) Visual, and (iii) Audiovisual, including data from 22 participants. Results showed a main effect of rhythmic sequences compared to random sequences across all frequencies in all three auditory, visual, or audiovisual conditions. Specifically, at 2 Hz, rhythmic sequences enhanced synchronization in the sensorimotor cortex for auditory and audiovisual conditions. This effect was absent in the visual condition alone. Notably, 2 Hz rhythmic sequences in the audiovisual condition led to synchronization with temporal, sensorimotor, and occipital regions. The study suggests that attention to rhythmic auditory input at 2 Hz can mediate neural synchronization between auditory and sensorimotor brain areas.