Studying Visual Motion Perception in the Lizard Anolis carolinensis using the Optomotor Response

The optomotor response is a powerful behavioral visual reflex that allows an animal to respond to motion in the surrounding environment. The reflex acts to stabilize the image of the visual world when the animal moves. This response plays a crucial role in the hunting strategy of Anolis carolinensis, a species of lizard native to the Americas. Anolis are adapted to a “sit-and-wait” strategy where they perch and look out for sudden movements in the surrounding environment. The optomotor reflex keeps the visual image of the world stable when the animal moves its head or eyes, allowing it to detect small moving objects in the visual scene. There is, however, a brief delay between when the motion is initially detected by the eye and when it is transduced into a response. This delay was studied extensively during my experiments. The optomotor response in an individual anole was elicited by a “moving world” of randomly positioned dots, created on a rotating drum. The drum movement could be adjusted by changing the period and frequency as well as the shape by using a sine or step function. Analysis of my data indicates that there is a brief delay between the motion stimulus and detection and further analysis will examine how this delay changes when the stimulus moves quickly versus moves slowly and when the movement is a sine wave vs a step wave.