Understanding others: imitation, language, empathy

Brain imaging techniques allow the mapping of cognitive functions onto neural systems, but also the understanding of mechanisms of human behavior. In a series of imaging studies we have described a minimal neural architecture for imitation. This architecture comprises a brain region that codes an early visual description of the action to be imitated, a second region that codes the detailed motor specification of the action to be copied, and a third region that codes the goal of the imitated action. Neural signals predicting the sensory consequences of the planned imitative action are sent back to the brain region coding the early visual description of the imitated action, for monitoring purposes ("my planned action is like the one I have just seen"). The three brain regions forming this minimal neural architecture belong to a part of the cerebral cortex called perisylvian, a critical cortical region for language. This suggests that the neural mechanisms implementing imitation are also used for other forms of human communication, such as language. Indeed, imaging data on warping of chimpanzee brains onto human brains indicate that the largest expansion between the two species is perisylvian. Functional similarities between the structure of actions and the structure of language as it unfolds during conversation reinforce this notion. Additional data suggest also that empathy occurs via the minimal neural architecture for imitation interacting with regions of the brain relevant to emotion. All in all, we come to understand others via imitation, and imitation shares functional mechanisms with language and empathy. 10/2/02. 3 1