The effect of lesions
Monkeys with collicular or frontal eye field lesions
make saccades with a slightly longer reaction time.
Monkeys with combined lesions cannot make
saccades at all.
Humans with parietal lesions neglect visual stimuli,
and make slightly hypometric saccades with longer
reaction times. Often their saccades are normal: if
they can see it they can make saccades to it.
Humans with frontal lesions cannot make
antisaccades.