Figure 1.

Typical setup for recording an electrooculogram. A. For recording horizontal saccades, electrodes are placed at the bilateral outer canthi, whereas for recording vertical saccades, electrodes are placed above and below one eye. B. Subjects are seated in front of a black, concave, dome-shaped screen measuring 90 cm in diameter that contains light-emitting diodes embedded in pinholes, which serve as the fixation points and saccade targets. The subject holds a microswitch button connected to the microcomputer, allowing the subject to initiate and terminate a task trial by pressing and releasing the button. The target point is turned on at a random location 5, 10, 20, or 30 degrees horizontally to the left or right of the central fixation point.