Motion Aftereffect

Motion Aftereffect refers to the following visual illusion - when you look at an object moving in one direction for a period of time, then look at a stationary object, the stationary object appears to be moving in the opposite direction. For example, when looking at a passing train going west, the nerves of the eye that are detecting that movement slowly adapt or lessen their activity. Later, when looking at a stop sign by the train tracks, the sign will appear to be moving east, just for a few seconds (less that a minute). This is because nerve cells that detect movement going toward the east become active and the stop sign appears to move.