Figure 2. The Virtual Environment.

The virtual rat is confined to move through a T-maze with return arms. Although it moves in small steps, the maze is divided into larger positions, numbered 1–5 for positions on the stem, 6–12 for positions on the right, and 6′–12′ for corresponding positions on the left. The rat begins in position 1 at the base of the stem, moving up the stem to the choice point at the top of the stem. Virtual reward zones are in the right and left corners of the maze. The arrows denote a correct trajectory with the rat alternating between right and left turns at the choice point.