Spatial Task for Rats Testing Position Recognition of an Object Displayed on a Computer Screen

We developed two spatial tasks for rats employing computer monitor for stimuli presentation. Both tasks were aimed for testing rats' ability to recognize position of a distant object. In the first task the object was stationary except moments when it jumped from one position to another. In the second task it moved continuously across the screen. Rats were trained in an operant chamber located in front of the monitor. They responded to the object position by pressing a lever for food reward. Responses were reinforced when the object was displayed in a to-be-recognized position in the first task and when it was passing through a to-be-recognized region in the second task. The to-be-recognized position as well as the to-be-recognized region had to be determined with respect to surrounding orientation cues. Responding rate of well trained rats negatively depended on the distance between the object and the to-be-recognized position/region. In the first task this relationship was apparent during a short time after the object changed its position and it held even for newly presented unfamiliar positions of the object. We conclude that in both tasks the rats recognize position of the object by estimating distance between the object and the to-be-recognized position/region. We also analyzed contribution of timing behavior to the solution of the second task.