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Abstract:
Abstract: Smooth pursuit eye movements allow primates to
follow moving objects with the eyes. Visual objects in the
environment do not always move randomly and often have predictable
trajectories. The memory about previous target motion improves the
performance of smooth pursuit and can compensate for delays present
in the visual system. Moreover, knowing the timing of future target
motion often causes the eyes to move before the actual stimulus
(anticipatory pursuit). The aim of this work was to determine
whether the primate supplementary eye fields (SEF) of the
dorsomedial frontal cortex could be involved in these cognitive
aspects of the control of smooth pursuit. Monkeys were trained to
pursue a visual target moving at constant velocity. Electrical
stimulation of the SEF was delivered through microelectrodes during
the period of preparation and initiation of pursuit. The direction
of target motion was either the same on every trial (predictable),
or varied randomly between left and right (unpredictable). In both
conditions, electrical stimulation increased eye acceleration at
pursuit initiation. This facilitatory effect was stronger when
target motion was predictable. Electrical stimulation also
increased the frequency and velocity of anticipatory pursuit. We
conclude that the SEF could be a site where cognitive factors
interact with motor programs for movement control.
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