Cortical activity during the recognition of cooperative actions.

We investigated brain activity during the recognition of cooperative actions between two persons. Participants were requested to observe movie clips in which one person received an object passed by another person and to rate the appropriateness of the hand-motion patterns of the receiver. The relative oxyhaemoglobin concentrations in the regions that are considered to be involved in the mirror neuron system (the inferior frontal and precentral areas) were measured by 24-channel near-infrared spectroscopy. The results revealed that the relative oxyhaemoglobin concentration increased to a greater extent during the observation of appropriate receiving actions than during the observation of inappropriate ones. These results suggest that the mirror neuron system is involved in the comprehension of cooperative actions.