Final answer:
Corollary discharge, or reafference, is a brain mechanism that distinguishes self-generated movements from external sensory events, helping maintain stable perception during movements such as eye motion.
Step-by-step explanation:
Corollary discharge (also known as reafference) is a neurophysiological concept describing the mechanism by which the brain differentiates between self-generated and externally generated sensory signals. When an organism initiates a movement, a signal (corollary discharge signal) is sent from the motor areas of the brain to the sensory areas. This signal informs the sensory areas that an upcoming change in sensory input will be the result of the organism's movement, allowing the brain to maintain a stable perception of the environment.
For example, when you move your eyes, the world does not appear to sweep across your retina, because the corollary discharge from the eye movement cancels out the sensory signals caused by the motion of the retina itself. This allows you to keep a stable view of the world despite the movement of your eyes.
It's a fundamental component in coordinating motor actions and sensory experiences, ensuring that the movements we make do not disrupt our perception of the world.