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Eileen Kowler, Lakshmi Kolisetty, Cordelia Aitkin, Nicholas Ross, Elio Santos, Radha Shah; Anticipatory smooth eye movements evoked by motor intentions. Journal of Vision 2015;15(12):1018. doi: 10.1167/15.12.1018.
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© ARVO (1962-2015); The Authors (2016-present)
Anticipatory smooth eye movements (ASEM) are predictive smooth eye movements in the expected direction of future target motion. ASEM are evoked by various cues that signal the direction of future target motion, including cues from our own motor intentions when we move targets ourselves (Kowler et al., 2014; Ross & Santos, 2014). How do motor intentions trigger ASEM? Does the pursuit system monitor motor commands directly, or, alternatively, use motor intentions, along with other cues, to represent the expected path of future target motion? These alternatives can be distinguished by imposing visuo-motor conflicts. Subjects pursued a target disk whose motion was controlled by a mouse. The disk was moved through an inverted Y-shaped tube, with subjects choosing either the right or left oblique pathway. In the absence of visuo-motor conflict, ASEM were found before the target entered the oblique pathway. Results were similar regardless of whether the mouse steered the target, or control was limited to choosing the right or left pathway via a brief deflection of the mouse at trial onset. In the presence of visuo-motor conflict, when the target moved opposite to the hand movement, ASEM on average corresponded to the expected direction of target motion, not the direction of hand movement. Managing the visuo-motor conflict introduced costs in that ASEM were slower when the target was guided through the entire path than when control was limited to simply choosing the right or left path at trial onset. The results show that high-level expectations dominate the influence of lower-level motor commands in generating ASEM with self-moved targets. Even expectations created by a simple choice of the path are effective. The results add to the evidence that neural signals representing the strength of beliefs about the trajectory of future motion are instrumental in controlling pursuit eye movements.
Meeting abstract presented at VSS 2015
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