The Neural Control of Visually Guided Eye Movements
C. Cortical Mechanisms of Visually Guided Saccadic Eye Movements


Based on these observations we can now delineate the computations that go on in the process of target selection with saccadic eye movements. This is outlined in Figure 27. Following each saccade to a new location, not only must the object in central view be analyzed, but at the same time a decision has to be made as to where to look next. We see 5 computations being carried out to accomplish this: the first under #1, is to determine what the objects are in the scene. This we know is carried out by many structures that include V1, V2, V4, IT and LIP. Second, one target needs to be chosen to be looked at. This decision, based on the facilitatory effects found, appears to involve areas V1, V2, LIP, the FEF and the MEF.

computations necessary for initiating visually guided saccades

Thirdly a decision needs also to be made as to which targets not to look at. This clearly involves V1, V2 and LIP as revealed by the noted interference effects which may well be a product of inhibitory feedback circuits activated by the electrical stimulation. Fourth, the spatial location of the targets needs to be computed to generate the correct saccade; this probably involves V1, V2, SC and the FEF in each of which receptive or motor fields are laid out in nice topographic order. Lastly, #5, a decision needs to be made as to when to initiate the saccade which appears to lie largely in the domains of area LIP and MEF.

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