Traveling Waves in the Human EEG during Voluntary Hand Movements

The trajectories of EEG traveling waves linked with movements of the right hand in a defined direction were recorded. A rectangle of 28 electrodes was positioned above the sensorimotor cortex, with seven electrodes in each row. A two-dimensional center-out reaching task was used. Targets appeared at the edge of the screen at random time intervals of 0.5–2.5 sec, with equal probabilities of appearing at the left, right, top, or bottom. The task was to use a joystick to move the cursor to touch the target, moving the cursor in one direction from the center to the edge. EEG traces were analyzed from the appearance of the target until it was touched. Spontaneous EEG waves showed phase anticipation in a local area of the left sensorimotor cortex and the posterior central parietal cortex on downward cursor movement (pulling movement of hand on joystick) as compared with the resting state and movements in the other three directions. Time smoothing of phase shift data using a sliding mean revealed otherwise cryptic constant components in the EEG resembling summation of evoked potentials. © 2015, Springer Science+Business Media New York.