Control of Visually Guided Eye Movements
D. Temporal Factors in Visually Guided Saccadic Eye Movements
1. The conditions
under which express saccades can and cannot be generated.
a. How important is it to extinguish the fixation
spot before the target is presented?
30 shows the distribution of saccadic
latencies using three different gap times, which is the time between the
termination of the fixation spot and the appearance of the target. With
a gap times of 100 milliseconds numerous express saccades occur (which
form the first peak of the bimodal distribution). The frequency of express
saccades falls off dramatically as the gap time is decreased. as shown
in the second and third panels of Figure 30.
When the fixation spot is not extinguised at all, express saccades become
extremely rare. Thus extinguishing the fixation spot 100-200 milliseconds
before the target onset is an important condition for express saccade