Visual evoked potential

A visual evoked potential (VEP) is an evoked potentialcaused by sensory stimulation of a subject's visual field. Commonly-used visual stimuli are flashing lights, or checkerboards on a video screen that flicker between black on white to white on black (invert contrast).

Visual evoked potentials are very useful in detecting blindness in patients that cannot communicate, such as babies or non-human animals. If repeated stimulation of the visual field causes no changes in EEGpotentials, then the subject's brain is probably not receiving any signals from his/her eyes. Other applications include the diagnosis of optic neuritis, which causes the signal to be delayed. Visual evoked potentials are also used in the investigation of basic functions of visual perception.

The term "visual evoked potential" is used interchangeably with "visually evoked potential". It usually refers to responses recorded from the occipitalcortex. Sometimes, the term "visual evoked cortical potential" (VECP) is used to distinguish the VEP from retinalor subcortical potentials.

The multifocalVEP is used to record separate responses for visual field locations.

See also

• Electroretinography
• Evoked potential
• International Society for Clinical Electrophysiology of Visionsv:Vep

This article is licensed under the GNU Free Documentation License.
It uses material from the http://en.wikipedia.org/wiki/Visual+evoked+potential Wikipedia article Visual evoked potential.