Figure 3

Illustration of the methodological approach to compute ONSET and OFFSET latencies. The black line represents the contacts between the stylus and the targets. The grey line represents resultant gaze velocity in the vertical plane. Numerical marks are defined as follows: 1 = onset of gaze saccade; 2 = end of the preceding hand movement; 3 = onset of the considered hand movement. Note that OFFSET latency of the movement n-1 is positive (saccade n began before the end of movement n-1) whereas the OFFSET latency of the movement n is negative (saccade n + 1 began after the end of movement n). It can also be observed that ONSET latency for movement n is longer than ONSET latency for movement n + 1.