Cortical Mechanisms of Human Imitation

TLDR: Two areas with activation properties that become active during finger movement, regardless of how it is evoked, and their activation should increase when the same movement is elicited by the observation of an identical movement made by another individual are found.

Abstract: How does imitation occur? How can the motor plans necessary for imitating an action derive from the observation of that action? Imitation may be based on a mechanism directly matching the observed action onto an internal motor representation of that action (“direct matching hypothesis”). To test this hypothesis, normal human participants were asked to observe and imitate a finger movement and to perform the same movement after spatial or symbolic cues. Brain activity was measured with functional magnetic resonance imaging. If the direct matching hypothesis is correct, there should be areas that become active during finger movement, regardless of how it is evoked, and their activation should increase when the same movement is elicited by the observation of an identical movement made by another individual. Two areas with these properties were found in the left inferior frontal cortex (opercular region) and the rostral-most region of the right superior parietal lobule. Imitation has a central role in human development and learning of motor, communicative, and social skills (1, 2). However, the neural basis of imitation and its functional mechanisms are poorly understood. Data from patients with brain lesions suggest that frontal and parietal regions may be critical for human imitation (3) but do not provide insights on the mechanisms underlying it. Models of imitation based on instrumental