Outcome and view of the player modulate motor area activity during observation of a competitive game

In a previous study, we demonstrated that the mirror neuron system is involved in watching competitive games performed by multiple players [Shimada, S., & Abe, R. (2009). Modulation of the motor area activity during observation of a competitive game. NeuroReport, 20, 979–983]. In the present study, we investigated whether mirror neuron system activity was modulated by the outcome of a competitive game as well as by the spatial relationship between the player and the observer. We measured the activity of motor areas using near-infrared spectroscopy when a subject watched a two-player competitive game, rock–paper–scissors (RPS). Some parts of the motor area that was activated while performing the RPS action were also activated while observing the RPS game. Interestingly, the magnitude of this activity (during observation) was modulated by the outcome and the view of the particular player whom the subject was supporting. In the dorsal anterior region of the motor area measured, the activity was significantly greater when the supported player won rather than when he lost, regardless of the view. It was also greater when the player was presented with an incongruent view than with a congruent view, regardless of the outcome. In contrast, the dorsal posterior region of the motor area was activated only when the supported player won and was observed with a congruent view. We suggest that mirror neuron system activity during observation of a competitive game reflects the subject's internal assimilation of the actions of the observed player.