Right parieto-premotor activation related to limb-independent antiphase movement.

In both quadrupedal and bipedal walking, cyclic movements of opposite limbs are made in antiphase, with identical frequency of all four limbs. These kinematical characteristics generated the hypothesis that, in humans, the cerebral control of this stereotypic movement pattern is associated with a common circuitry involved in antiphase movement, independent from execution by either the two upper or the two lower limbs. By means of positron emission tomography (PET), we identified cerebral activations related to limb-independent antiphase movement, distributed over the right anterior parietal and the right dorsal premotor cortex. Particularly, involvement of the right parietal cortex demonstrates a lateralized brain function for higher-order somatosensory processing, enabling the sensorimotor anchoring of stereotypic multilimb movement.