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Delphine Massendari, Matteo Lisi, Thérése Collins, Patrick Cavanagh; A dissociation between the perceptual and saccadic localization of moving objects for reactive saccades but not for memory-guided saccades. Journal of Vision 2016;16(12):934. doi: 10.1167/16.12.934.
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© ARVO (1962-2015); The Authors (2016-present)
The double-drift stimulus leads to a large discrepancy between the physical path of a moving gabor and its perceived direction. Saccades directed to the double-drift stimulus land along the physical, and not perceived, path (Lisi & Cavanagh, 2015). Here we asked whether memory-guided saccades exhibited the same dissociation from perception. We used the same stimuli as in Lisi and Cavanagh (2015): a single gabor moving back and forth along a linear trajectory while its internal motion drifted in the orthogonal direction. During presentation, participants were asked to keep their eyes focused on the fixation dot, such that the drifting gabor was in the periphery. The gabor disappeared (four possible offset locations) and after a variable delay (0-1000 ms), the fixation dot was removed, serving as the go-signal to make the saccade to the remembered location of the offset. With no delay, we replicated the finding that saccades target the physical, and not perceived, location. However, with delays as short as 250 ms, saccade endpoints shifted towards the perceived location. Moreover, the longer the delay, the higher the probability that endpoints landed near the perceptual position. Our result shows that while reactive saccades target physical stimuli, memory-guided saccades target perceived stimuli.
Meeting abstract presented at VSS 2016
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