Brain network and activity in frontal regions change in the process of visuomotor adaptation

Frontal regions are involved in early stages of motor adaptation. However, the interactions between prefrontal cortex (PFC) and motor cortex (MC) remain unclear. Therefore, we investigated the relationship between PFC and MC in the process of motor adaptation including the early stage, using analyses of brain activity and its effective connectivity (EC). To promote motor adaptation, right-handed participants were trained to perform a visuomotor task with their right hand. To investigate the involved brain networks, their brain activity before and after training was measured by near-infrared spectroscopy (NIRS). EC analysis revealed that the brain network connecting the right PFC and contralateral (left) MC attenuated after the visuomotor training. Brain activity analysis showed the significant decrease in the ipsilateral (right) primary motor cortex (M1) after the visuomotor training. These results suggest that the PFC and MC are synchronized at the early stages of motor learning but act independently through the motor adaptation.