Optokinetic nystagmus occurs in response to what kind of stimulus?

Optokinetic nystagmus is a specific type of eye movement that occurs in response to contrasting moving images. This reflex is a physiological phenomenon where the eyes automatically and rhythmically follow a moving stimulus across a visual field before quickly snapping back to a designated point in order to stabilize the gaze. It's particularly notable when an individual views a scene with stripes or distinct patterns that move horizontally or vertically, such as passing scenery through a train window.

This reflex is significant in helping maintain visual stability during head and body movements, effectively allowing tracking of motion. The presence of contrasting moving images is essential because it provides the necessary visual cues for the optical system to engage in the nystagmus response.

In contrast, sudden bright lights, fixed objects, or quick head movements do not typically stimulate optokinetic nystagmus, as they do not involve the movement of visual stimuli across the field of view in the manner required to elicit this specific response.