| |
Abstract:
The superior colliculus (SC) is essential for the "visual
grasp" reflex - a rapid shift of the eyes towards a suddenly
appearing visual stimulus. In contrast, the frontal eye field (FEF)
is thought to be important for the control of purposive voluntary
saccades. To investigate the role and the relationship of SC and
FEF neurons in the suppression of the reflexive saccades and in the
generation of voluntary saccades, we recorded from single neurons
in both areas in monkeys trained on a pro-/anti-saccade task. The
color of the initial fixation point instructed the animals to
either generate a saccade to a visual stimulus (pro-saccade) or a
saccade to the opposite side (anti-saccade). Fixation neurons in
the SC and FEF had an increased activity during fixation on
anti-saccade compared with pro-saccade trials, whereas saccade
neurons in the SC and FEF showed the opposite activity pattern.
Saccade neurons in the SC and FEF had lower stimulus-related
responses on anti-saccade compared with pro-saccade trials. These
saccade neurons discharged for anti-saccades into their response
field, however, the discharge was lower for anti-saccades compared
with pro-saccades. Our results demonstrate that both SC and FEF
neurons participate in the suppression of reflexive saccades and in
the generation of voluntary saccades.
|
