Cortical involvement for action imitation of hand/arm postures versus finger configurations: an fMRI study.

We used fMRI to study the human imitation of hand/arm postures and finger configuration, subjects imitated hand/arm postures in the hand condition, and they imitated finger configurations in the finger condition. Compared with the control condition, only the finger condition showed significant activation in Broca's area and symmetrical activation in the bilateral inferior parietal lobes, while the hand condition showed left lateralised superior parietal activation pattern. Our findings suggest that Broca's area might be involved more in the imitation of finger configuration than that of hand/arm postures. The result of parietal activation patterns was fully consistent with formerly reported clinical findings, and the relationship between the lesion laterality and the patients' perfomance of hand/finger action imitation.