Saccade
2021.8.10
Information concerning moving targets and information governing scanning of the eyes travels to a second site in the brainstem, a nucleus called the superior colliculus. The superior colliculus is responsible for moving the eyes in short jumps, called saccades. Saccades allow the brain to perceive a smooth scan by stitching together a series of relatively still images. Saccadic eye movement solves the problem of extreme blurring that would result if the eyes could pan smoothly across a visual landscape; saccades can be readily observed if you watch someone's eyes as they attempt to pan their gaze across a room. (1. How Vision Works, BrainHQ)

Humans and many animals do not look at a scene in fixed steadiness; instead, the eyes move around, locating interesting parts of the scene and building up a mental, three-dimensional 'map' corresponding to the scene ... When scanning immediate surroundings or reading, human eyes make jerky saccadic movements and stop several times, moving very quickly between each stop. The speed of movement during each saccade cannot be controlled; the eyes move as fast as they are able.[3] One reason for the saccadic movement of the human eye is that the central part of the retina—known as the fovea—which provides the high-resolution portion of vision is very small in humans, only about 1–2 degrees of vision, but it plays a critical role in resolving objects.[citation needed] By moving the eye so that small parts of a scene can be sensed with greater resolution, body resources can be used more efficiently.

Main article: Saccadic masking
It is a common but false belief that during the saccade, no information is passed through the optic nerve to the brain. Whereas low spatial frequencies (the 'fuzzier' parts) are attenuated, higher spatial frequencies (an image's fine details) that would otherwise be blurred by the eye movement remain unaffected. This phenomenon, known as saccadic masking or saccadic suppression ... leads to the so-called stopped-clock illusion, or chronostasis.

When a visual stimulus is seen before a saccade, subjects are still able to make another saccade back to that image, even if it is no longer visible. This shows that the brain is somehow able to take into account the intervening eye movement. It is thought that the brain does this by temporarily recording a copy of the command for the eye movement, and comparing this to the remembered image of the target. This is called spatial updating. Neurophysiologists having recorded from cortical areas for saccades during spatial updating have found that memory-related signals get remapped during each saccade.[citation needed]

It is also thought that perceptual memory is updated during saccades so that information gathered across fixations can be compared and synthesized. However, the entire visual image is not updated during each saccade. Some scientists believe that this is the same as visual working memory, but as in spatial updating the eye movement has to be accounted for. The process of retaining information across a saccade is called trans-saccadic memory, and the process of integrating information from more than one fixation is called trans-saccadic integration.
(We are locked into the world of our own perceptions, believing that others know the world in the same way, but she sensed, for as long as she could remember that she was different, and did not see what others around her experienced. She felt, by the subtle reactions of her parents and family who knew her best and presumably loved her without condition, that something was off. Try as she did to knuckle down to the expectations of others, she was constantly blindsided by situations where she had no other way forward but through her own private sufferance.)
Where others saw the smoothing over of a million singular perceptions into one believable picture of the universe, her own brain predisposed her to see a stuttering ghosting of movement between objects, a shimmering of energy and light bending and bouncing. Things did not, for her, have edges, autonomy and wholeness and the object-ness that most people apparently assumed without a thought, but for her were always giving and taking, becoming and once was, in a fast-forward like motion that never stopped, but bore an imprint upon her, a kind of sorrow of what they once were. Sorrow, because while others were blithely going about their business she was wracked with a kind of desperation to know what to pay attention to and what to memorialize, what would never come again in this particular beauty.
Sorrow because she was unutterably alone in it and could not share it.
Though it was also a kind of magic, a suspenseful dream where until the moment she closed her hand over a book or a doorknob, for example, to feel the solid smoothness, or the slickness of the binding, she could not be sure her hand would find what she was looking for, or that any particular object would let her find it. In her own new house she had been like a blind thing until she had mapped the distances that stayed the same, a small space that she could triangulate within. Home for her was more than comfort, it was a bedrock from which she could flow out into the world of such mesmerizing complexity that she was sometimes stunned into stillness that others took for fear or anxiety, which it was of course, but so much more, as she stepped each day through a chaos of space and time, noise and light and color that knit and unknit around her, while parents, teachers, and her peers constantly also demanded of her her attention and responses that seemed geared to ignoring all of it for some small place where the others inhabited, and she learned to make her own responses small and ambiguous while yearning to embrace and extoll this freewheeling and glorious beauty that promised joy. she wanted others to stop and see it too.
Music seemed particularly suited to this particular problem she had of time and space, the playing of a composition being the closest to thought and feeling being repeated in formulation, but she soon had gone as far as she could in that study, with her talent.