Cognitive Neuroscience Talks

Neural substrates for imitation at different levels of action description in the human brain revealed by fMRI adaptation

Imitation of complex movements and abstract action goals is an important skill for our social interactions. Premotor, parietal and superior temporal areas have been implicated in action understanding and imitation. What is the role of these different cortical areas in the imitation of actions at different levels of action description: from the representation of detailed physical trajectories to the processing of distinct action features that allow us to discriminate between abstract action goals and personal actor styles? We addressed this question using kinematic morphs of arm movements, matching movements for either their action goal or their average kinematics and employing sensitive fMRI adaptation/repetition suppression methods. We provide novel evidence for differential involvement of ventral premotor and parietal and temporal regions in movement imitation. We show that the ventral premotor cortex encodes the physical similarity between movement trajectories that is important for exact copying of actions and the acquisition of complex motor skills, whereas parietal regions and the STS process the perceptual similarity between movements and may support imitation of abstract action goals and personal movement styles. Our findings propose a circuit of fronto-parietal and visual areas that mediate a cascade of visuomotor processes at different levels of action description.