Neural activation during imitation of movements presented from four different perspectives: a functional magnetic resonance imaging study.

The present study examined the effects of the perspective of movement presented for imitation in healthy volunteers, using functional magnetic resonance imaging (fMRI) to assess the magnitude and distribution of elicited brain activity. We sought to identify the pattern of brain activity associated with the performance of finger imitation tasks under four different imitation conditions. Video presentations of a hand and forearm performing random sequential contact between different fingers and the thumb were presented for imitation, while fMRI was recorded. The four types of model for imitation were: a hand and forearm pointing away from the subject, as if the subject were looking at their own limb (first-person perspective), from both anatomical (a right hand to be imitated by the subject's own right hand) and specular (a mirror image or "left" hand to be imitated by the subject's right hand) perspectives; and a hand/forearm pointing toward the subject, as if it was the hand of another person facing the subject (third-person perspective), from both anatomical (the opposite person's right hand) and specular (the opposite person's left hand) perspectives. In addition, participants completed a motor control task. The results revealed a significant difference in the magnitude of brain activation between the first- and third-person perspective conditions, suggesting that subjects used the first-person imitation model as a substitute for internal self-representation, thus requiring less effort. The first-person perspective anatomical model activated only the right posterior insula, recruiting significantly fewer brain regions than the other model types, compared with the control condition. These findings suggest that first-person anatomical perspective models may be optimal for ease of imitation in motor learning.