Effector-independent brain activity during motor imagery of the upper and lower limbs: An fMRI study

•Brain activity was measured by functional magnetic resonance imaging.•We evaluated the common brain region of motor imagery of the right/left hands or feet.•The left supplemental motor area and inferior frontal gyrus were commonly activated.

We utilized functional magnetic resonance imaging (fMRI) to evaluate the common brain region of motor imagery for the right and left upper and lower limbs. The subjects were instructed to repeatedly imagined extension and flexion of the right or left hands/ankles. Brain regions, which included the supplemental motor area (SMA), premotor cortex and parietal cortex, were activated during motor imagery. Conjunction analysis revealed that the left SMA and inferior frontal gyrus (IFG)/ventral premotor cortex (vPM) were commonly activated with motor imagery of the right hand, left hand, right foot, and left foot. This result suggests that these brain regions are activated during motor imagery in an effector independent manner.