FIGURE 1.

Experimental procedures and pictures presented for the left–right arrow task (A) and hand mental rotation task (B). (A) Following presentation of a fixation point for 1.5 s, a picture of an arrow pointing to the left or right was presented and subjects were simply required to indicate the correct direction. (B) In the hand mental rotation task (HMRT), a picture of a hand back (back-of-hand condition) or palm was presented with index finger point medial or lateral. Subjects were required to determine whether the hand was the left or the right based on visual or motor imagery.