Learning from the other limb's experience: sharing the ‘trained’ M1 representation of the motor sequence knowledge

Participants were scanned during the untrained‐hand performance of a motor sequence, intensively trained a day earlier, and also a similarly constructed but novel, untrained sequence. The superior performance levels for the trained, compared to the untrained sequence, were associated with a greater magnitude of activity within the primary motor cortex (M1), bilaterally, for the trained sequence. The differential responses in the ‘trained’ M1, ipsilateral to the untrained hand, were positively correlated with experience‐related differences in the functional connectivity between the ‘trained’ M1 and (1) its homologue and (2) the dorsal premotor cortex (PMd) within the contralateral hemisphere. No significant correlation was evident between experience‐related differences in M1 – M1 and M1 – PMd connectivity measures. These results suggest that the transfer of sequence‐specific information between the two primary motor cortices is predominantly mediated by excitatory mechanisms driven by the ‘trained’ M1 via two independent neural pathways.