OptoDrumThe Ultimate Optomotor Drum
OptoDrum: The Ultimate Optomotor Drum
The animal sits on an elevated platform, surrounded by computer monitors. A camera observes the behavior of the animal from above while a visual stimulus, a virtual striped cylinder, is projected onto the screens. The stripe pattern slowly rotates around the animal, triggering the optomotor reflex. This means that the animal follows the stripe pattern with its gaze by moving its head. This head movement is automatically detected and analyzed by the OptoDrum software. In addition, the projected pattern is continuously and automatically adjusted so that the animal is always in the center of the cylinder. As a result, the spatial frequency of the stripe pattern stays constant in all directions.
In a staircase procedure, the stripe pattern is made more difficult to be seen, by reducing either the contrast or the width of the stripes, until the animal fails to follow the stimulus with its head movements. The assessment of whether or not the animal follows the rotating stimulus, is done automatically by the OptoDrum software. This removes any observer bias, and it makes the experimental outcome objective. Further, even untrained personnel can immediately use the OptoDrum.