Figure 1.

The time course of a single trial consisted of three states: relaxed state, cue state, and motor imagery state. The directions were displayed on a monitor in front of the subjects. A trial started with an 8-s period of a relaxed state during which the word "Rest" was shown at the center of the monitor. After that, a 2-s period during which a word "Ready" was shown began. Then, the word "Start" was presented for 5 s, and subjects were asked to imagine themselves grasping something with their right hand