Search results
Results From The WOW.Com Content Network
A reflexive saccade is triggered exogenously by the appearance of a peripheral stimulus, or by the disappearance of a fixation stimulus. A scanning saccade is triggered endogenously for the purpose of exploring the visual environment. In an antisaccade, the eyes move away from the visual onset. They are more delayed than visually guided ...
Microsaccades are a kind of fixational eye movement.They are small, jerk-like, involuntary eye movements, similar to miniature versions of voluntary saccades.They typically occur during prolonged visual fixation (of at least several seconds), not only in humans, but also in animals with foveal vision (primates, cats, dogs etc.).
To perform the anti-saccade task, an individual is asked to fixate on a motionless target (such as a small dot). A stimulus is then presented to one side of the target. The individual is asked to make a saccade in the direction away from the stimulus. For example, if a stimulus is presented to the left of the motionless target, the patient ...
Newer studies have used a threshold of up to 2° to categorize microsaccades, expanding the definition by an order of magnitude. The distribution of saccade amplitudes is unimodal, giving no empirical threshold to distinguish microsaccades and saccades. Poletti et al. propose using a threshold based on the amplitude of sustained fixations and ...
Participants focused on the cross fixation and pressed a button at the start of the trial. After 100 ms a sequence of the three frames were presented, participants were then instructed to make a saccade to either the numerical saccade target or to an opposite character. Once the saccade target was identified participants pressed a button.
The saccade lasts for 20–40 ms and during this time vision is suppressed so that no new information is acquired. [15] There is considerable variability in fixations (the point at which a saccade jumps to) and saccades between readers and even for the same person reading a single passage of text.
The phenomenon described by Bridgeman et al. (Bridgeman, G., Hendry, D., & Stark, L., 1975) is characterized by the inability to detect changes in the location of a target when the change occurs immediately before, during, or shortly after the saccade, following a time course very similar to that of the suppression of visual sensitivity, with a ...
During each saccade the eyes move as fast as they can and the speed cannot be consciously controlled in between the fixations. [11] Each movement is worth a few minutes of arc, at regular intervals about three to four per second. One of the main uses for saccades is to scan a greater area with the high-resolution fovea of the eye. [13]