A possible role for primary motor cortex during action observation

Social interaction depends on the ability to infer beliefs and intentions in the minds of others. Little is known about the neural basis of our ability to “read” the intentions of others, but a likely candidate is the mirror-neuron system (MNS). Mirror neurons discharge not only during action execution but also during action observation. It is this property that makes these neurons a possible neural substrate for action understanding. The notion that actions are intrinsically linked to perception was proposed by William James, who suggested that “every mental representation of a movement awakens to some degree the actual movement which is its object” (1). The implication is that observing, imagining, preparing, or in any way representing an action excites the motor program used to execute that same action (2, 3).