Sensory and Motor Components of Smooth Pursuit Eye Movements in Extrastriate Cortex
Ample evidence from monkey electrophysiology suggests that eye movements are controlled by two parallel cortico-cortical networks, including a frontal eye field (FEF) and a parietal eye field (PEF). Each cortical eye field contains largely separate groups of neurons devoted to either saccadic eye movements, or visual pursuit eye movements (Tian and Lynch 1996). Both eye fields are directly connected to the brain stem oculomotor system. The posterior eye movement network has strong [anatomical and functional] links to the visual “dorsal stream”, and especially to motion perception. Experimental studies in non-human primates suggest that areas MT/MST are intimately involved in pursuit tracking (Newsome et al. 1985; Dursteier et al. 1987). If a given motion is misperceived or not seen at all, the target cannot be pursued faithfully (Baloh et al. 1980). This implies that information about an ongoing eye movement must be incorporated at some level(s) of the visual motion processing hierarchy. Here we ask at a systems level how analoguous regions in human cortex are interrelated. Human neuroimaging studies have clarified the localization of saccade-related activity (for a review see Carter and Zee 1997). However, only few imaging studies have addressed the functional anatomy of smooth pursuit eye movement in extrastri-ate visual cortex (Petit and Clark 1997; Barton et al. 1996). Previous human brain imaging experiments have also examined cortical responses to stimulus motion (e.g. Watson et al. 1993; Dupont et al. 1994; Tootell et al. 1995b; Tootell et al. 1997). Less is known about how the actitvity in specific motion areas is related to different components of an ongoing pursuit eye movement.
KeywordsSmooth Pursuit Dorsal Stream Motion Area Retinal Slip Cortical Surface Reconstruction
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