Effects of action observation training on brain network efficency during motor tasks

Motor skills, such as manual dexterity, are the result of complex cognitive processes that rely on the activation and interaction of distributed brain networks. The acquisition and improvement of motor skills seems to be associated with the increased efficiency and organization changes of such networks. Therefore, motor training aimed at the acquisition, improvement or recovery of a specific skill should involve the modulation of brain circuits and activity. In this study, we present an EEG-based functional connectivity analysis to evaluate the neurophysiological effects of action observation training (AOT) on healthy volunteers, specifically designed to improve manual dexterity. Precisely, we tested three groups of participants before and after three weeks of training: a group that received AOT in the morning, a group that received AOT just before bedtime, and a control group that received a sham intervention. Using network descriptors defined by graph theory (i.e., degree, modularity, and global efficiency), we observed changes in network organization between resting state and motor execution, and between pre- and post-training in the AOT groups. Specifically, an evident but not significant increase in global efficiency for sensorimotor rhythms was observed in the group performing AOT before sleep time, while no changes were observed for controls. These results therefore suggest a possible effect of AOT on functional networks organization.