A new apparatus is described in which cats must perform a visually guided movement of the forepaw toward a quasi-randomly moving target in order to obtain a reward. The target is a small bulb fixed to the pen carrier of an XY plotter; it moves under a translucent screen and is only visible to the cat when the bulb comes on at the onset of each trial. Sine waves of variable frequency are applied to the X and Y channels, the resulting target trajectory being a complex Lissajous pattern, unpredictable for the animal. Response times of accurate presses (detected by a capacity detector) are calculated and various types of misreachings can be coded, allowing quantification of performance, and comparison between normal and lesioned cats.