Brain activities associated with two-handed interactive movement during different motor forms

Motor observation (MO) and motor imagery (MI) are important methods for motor learning. Abundant studies have explored the process mechanism of simple single-hand movements, however the brain activity patterns for two-hand interactive movements have not been widely studied. Although combined synchronously motor observation (MO) and motor imagery (MI) for one movement can enhance motor performance, the brain mechanisms underlying the performance of MO + MI sequentially in two successive different movements remains unclear. In particular, it is unclear how the former motor task influences the latter, and how the two motor tasks can be exchanged. In this study, we recruited participants without any basketball experience and asked them to complete a throwing basketball movement with their left and right hands in different motor forms (MO-MO, MO-MI, MI-MO, and MI-MI), and assessed the brain mechanisms through functional connectivity (FC) and phase-amplitude coupling (PAC). The results revealed brain connections in the fronto-parietal and parieto-occipital networks. Owing to the necessity of motor intention adjustment and attention preparation, the connection was particularly strong during the left- and right-hand exchange periods. In addition, theta oscillation phase coupling on the amplitudes of alpha, beta, and gamma oscillations appeared in all motor patterns, suggesting that theta oscillation coordinated and modulated higher-frequency oscillations to help participants integrate the information between the first and second stages. In addition, MO-MI had stronger brain activities than MI-MI, indicating that not only the visual information for implicit learning and motor transfer from MO in the first stage, but also underlying imagery induced by MO, enhanced the motor performance of MI in the latter period.