Is the mirror neuron system involved in imitation? A short review and meta-analysis

It has been suggested that the mirror neuron system provides an important neural substrate for humans' ability to imitate. Mirror neurons have been found during single-cell recordings in monkeys in area F5 and PF. It is believed that the human equivalent of this mirror system in humans is the pars opercularis of the inferior frontal gyrus (area 44) and the rostral part of the inferior parietal lobule. This article critically reviews published fMRI studies that examined the role of frontal and parietal brain regions in imitation. A meta-analysis using activation likelihood estimation (ALE) revealed that the superior parietal lobule, inferior parietal lobule, and the dorsal premotor cortex but not the inferior frontal gyrus, are all commonly involved in imitation. An additional meta-analysis using a label-based review confirmed that in the frontal lobe, the premotor cortex rather than the inferior frontal gyrus is consistently active in studies investigating imitation. In the parietal region the superior and inferior parietal lobules are equally activated during imitation. Our results suggest that parietal and frontal regions which extend beyond the classical mirror neuron network are crucial for imitation.