Artikel
Frontal correlates of decision where to look
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Veröffentlicht: | 22. September 2004 |
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Gliederung
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Deciding where to look is mandatory to explore the visual world, but little is known about the neural correlates subserving the cognitive phase of self-initiated eye movements in humans. We tested the hypothesis that distinct frontal areas subserve decision in self-initiated saccades when compared to preparation of externally-triggerred visually guided saccades. Ten healthy subjects were studied using event-related fMRI, aiming to separate the cognitive and executive components of the visuomotor task. Changes in the cortical activity preceeding voluntary saccades were studied when the subjects freely decided the direction of a forthcoming saccade, and when they only had to prepare a cued saccade to one of two synchronous peripheral visible targets. The preparatory set of cued saccades involved mainly the frontal eye fields, whereas free decision of where to direct a forthcoming saccade was associated with additional activation in the dorsolateral prefrontal cortex, the pre-supplementary eye field and the anterior cingulate cortex. Execution of visually guided saccades activated a classical frontoparietal network including the frontal, supplementary and parietal eye fields. These findings suggest an anterior-posterior organisation in the frontal lobe, subserving distinct cognitive processes prior to saccade execution.