Editing Saccadic masking (section)

==Mechanism==

A [[saccade]] is a fast [[Human eye|eye]] motion, and because it is a motion that is optimised for speed, there is inevitable blurring of the image on the [[retina]], as the retina is sweeping the visual field. Blurred retinal images are not of much use, and the eye has a mechanism that "cuts off" the processing of retinal images when it becomes blurred. This phenomenon is called saccadic masking or saccadic suppression. There were two major types of saccadic masking claimed: [[flash suppression]] (the inability to see a flash of light during a saccade<ref>Dodge, 1900</ref>) and [[saccadic suppression of image displacement]] (characterized by the inability to perceive whether a target has moved or not during a saccade).<ref>Bridgeman, G., Hendry, D., & Stark, L. 1975</ref> Testing since then has revealed that these two theories may not be correct.<ref>{{Cite news |last=Charles |first=Krista |title=We thought our eyes turned off when moving quickly, but that's wrong |url=https://www.newscientist.com/article/2285131-we-thought-our-eyes-turned-off-when-moving-quickly-but-thats-wrong/ |access-date=2022-12-18 |website=New Scientist |language=en-US}}</ref> Within-saccade movement detection was proven and detailed in a paper by Richard Schweitzer and Martin Rolfs at Humboldt University in Berlin.<ref>{{Cite journal |last1=Schweitzer |first1=Richard |last2=Rolfs |first2=Martin |date=23 July 2021 |title=Intrasaccadic motion streaks jump-start gaze correction |journal=Science Advances |volume=7 |issue=30 |doi=10.1126/sciadv.abf2218 |pmid=34301596 |pmc=8302125 |bibcode=2021SciA....7.2218S |doi-access=free}}</ref>

Because saccadic suppression starts before the actual onset of the saccade, it cannot be triggered by retinal motion and must be centrally activated by the brain. Supporting this idea, a significant reduction of the cortical signals retinotopically encoding stimuli briefly presented immediately before the execution of a saccade has been found as early as in primary visual cortex.<ref>Vallines, I., & Greenlee, M.W., 2006</ref>