Brain activation by a VR-based motor imagery andobservation task: An fMRI study

Training motor imagery (MI) and motor observation (MO) tasks is being intensively exploited to promote brain plasticity in the context of post-stroke rehabilitation strategies. The desired brain plasticity mechanisms may benefit from the use of closed-loop neurofeedback, embedded in brain-computer interfaces (BCIs) to provide an alternative non-muscular channel. These can be further augmented through embodied feedback delivered through virtual reality (VR). Here, we used functional magnetic resonance imaging (fMRI) to map brain activation elicited by a VR-based MI-MO BCI task called NeuRow and compared with a conventional non-VR, and MI-only, task based on the Graz BCI paradigm. We found that, in healthy adults, NeuRow elicits stronger brain activation when compared to the Graz task, as well as to an overt motor execution task, recruiting large portions of the parietal and occipital cortices in addition to the motor and premotor cortices. In particular, NeuRow activates the mirror neuron system (MNS), associated with action observation, as well as visual areas related with visual attention and motion processing. We studied a cohort of healthy adults including younger and older subgroups, and found no significant age-related effects in the measured brain activity. Overall, our findings suggest that the virtual representation of the arms in a bimanual MI-MO task engage the brain beyond conventional MI tasks, even in older adults, which we propose could be explored for effective neurorehabilitation protocols.