The Neural Control of Visually Guided Eye Movements
D. Temporal Factors in Visually Guided Saccadic Eye Movements

It has been suggested that express saccade generation involves the parasol system (see Section 1, III & IV). To examine this idea we tested animals with restricted retinal regions that lacked either midget or parasol cell projections to cortex as produced by parvocellular and magnocellular lesions of the lateral geniculate nucleus (LGN). As shown in the panels on the left in Figure 44, neither of these lesions affected express saccadde generation.

Also examined were the effects of area V4 and the middle temporal (MT) area. These lesions, including conditions in which both areas had been removed, as shown on the right in Figure 44, did not affect the production of express saccades.

Thus it appears that the superior colliculus and parts of the posterior system that project to it are essential for producing express saccades.