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Abstract:
Abstract: We present here results obtained using a new
paradigm developed to elucidate the functional role of the SEF. In
this paradigm, the monkey fixates a red spot at the center of the
screen for 500 msec, during which time a bluish-white target
appears 20 deg either left or right of center, and subsequently
moves (typically 30 deg/sec) towards the fixation spot. The monkey
must first fixate until the moving target crosses the central
fixation spot. The fixation spot then either disappears or remains
on, while the target continues to move into the periphery. Reward
is given for pursuing the target when the fixation spot is
extinguished (go), or for holding fixation when the fixation point
stays on (nogo). Single neurons were recorded in the SEF in
sessions where the relative percentage of go/nogo trials was
manipulated. Most cells responding during this task were activated
either before the target crossed the fixation point, before the
reward was given or at both times, consistent with the idea that
the SEF is involved in movement planning and reward timing.
However, a separate class fired more vigorously when the monkey
successfully withheld pursuit to the moving target and continued
fixating than when he was allowed to pursue the target. The results
suggest that the SEF plays an executive role in the control of
eye-movements.
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