BIMANUAL CONTROL IN TRAINED MUSICIANS: COORDINATION AND INTERHEMISPHERIC INTERACTIONS

Musicians demonstrate superior control in bimanual tasks, characterized by reduced variability and greater synchrony in out-of-phase tapping¹. Fine bimanual motor control and coordination requires both direct corticospinal pathways and extensive interhemispheric communication. Recent studies have suggested that, similar to the sensory system, the motor system expresses center-facilitation–surround-inhibition patterns of excitation. This pattern enhances the excitability of contralateral homologous muscles while reducing excitability in surrounding contralateral muscles, which is believed to be critical for the precise coordination of finger movements. The current study aims to investigate whether bimanual behavioral performance is associated with alterations in excitability profiles of the first dorsal interosseous (FDI) and abductor digiti minimi (ADM) during contralateral muscle activation and at rest, thereby characterizing interhemispheric interactions at the level of individual finger representations. We hypothesize that musicians will exhibit superior bimanual control as well as a stronger center-facilitation–surround-inhibition pattern between FDI and ADM. Musicians and non-musicians (expected N = 20 in each group) perform bimanual finger-tapping tasks followed by transcranial magnetic stimulation (TMS) to assess corticospinal excitability in FDI and ADM during contralateral homologous muscle activation and rest. Preliminary behavioral data (N = 10) confirms that musicians maintain a greater voluntary control throughout the out-of-phase tapping, while non-musicians struggle to inhibit falling into mirrored tapping. Ongoing analyses will examine the relationships between tapping performance, corticospinal excitability, and interhemispheric inhibition at the level of individual finger muscles. These findings will illuminate how long-term motor skill training shapes interhemispheric communication, motor interactions and fine motor control.