Figure 2

Quantification of timing variables from eye and hand movement signals. Traces of eye (solid line) and hand movements (dashed line) during the performance of a pro-tapping task trial. At time 0 ms, the blue dot which is the target location for both eye and hand movement, is displayed at a position of +15 degrees with respect to the central dot. The triangle (▲) represents the moment the finger is released from the touch screen, whereas the reversed triangle (▼) represents the moment the target dot is touched. Eye latency (EL) was defined as the time between presentation of the target and the start of the saccade towards it. Hand latency (HL) is the time between presentation of the target and the release of the finger from the screen (▲). Hand execution time (HET) is the time between the release of the finger from the screen and the touch of the target (▲ to ▼). The kinematic variable hand maximal velocity (HMV) is determined from the peak velocity of the hand between start and end of a hand movement.