The neural mechanisms of reciprocal communication.

Imitation in humans has been attributed to increased activation of the mirror neuron system, but there is no neural model to explain reciprocal communication. In this study, we investigated whether reciprocal, communicative, imitative exchanges activate the same neural system as imitation of simple movements, and whether the neural network subserving communication is lateralized. Fifteen participants were tested using functional magnetic resonance imaging with an online interactive-imitative paradigm while they performed finger movements for three different purposes: (1) to imitate the experimenter, (2) to elicit an imitation from the experimenter, and (3) to simply perform the movement. Subtraction analysis (imitation > movement, initiation > movement) revealed the activation of a strongly lateralized network, where the infra-parietal lobule (IPL) activation was lateralized to the left, while the infero-frontal gyrus (IFG) activation was to the right. It is concluded that imitation in a communicative paradigm recruits a lateralized network, with left fronto- and right parietal activation, that overlaps with a network that subserves understanding of an Other's intentions in relation to the Self. This finding lends plausibility to the suggestion that the neural network for imitation evolved to support interpersonal communication.