Neostriatal lesions impaired rats' delayed alternation performance in a T-maze but not in a two-key operant chamber

Rats with lesions in the neostriatal region that belongs to the prefrontal system were trained in two versions of delayed alternation. They performed as proficiently as intact animals in a two-key operant chamber. The same operated rats took many more trials to reach criterion when subsequently compared with the same control group in a T-maze. This finding demonstrates that variants of delayed alternation are not equivalent for animals with lesions in the prefrontal system. Observations suggested that delayed alternation in the operant chamber may be mastered by positional mediation.