Figure 3.

Exposure to an escalating dose regimen of MA impairs the performance of rats in the stable PRL. (a, b) Average probability of each choice (red: highest reinforced option during the acquisition phase; green: highest reinforced option during the reversal phase; blue: option associated with an intermediate level of reinforcement in both task phases) during the acquisition and reversal phase of the stable PRL in rats exposed to SAL (left) or MA (right). Shaded area is the SEM. (c) The probability of choosing the highest reinforced option during the acquisition phase of the stable PRL was not different between rats exposed to saline (purple) or MA (orange). However, performance in the reversal phase was significantly lower in rats exposed to MA compared with saline. (d) The impaired performance of rats exposed to MA in the reversal phase was because of an increase in the probability that rats would make a perseverative response. (e) Rats exposed to MA were more likely to persist with the same choice following a trial that did not result in reward than rats exposed to SAL. (f) The computational analysis of choice behavior in the stable PRL indicated that rats exposed to MA had a higher Δ₂ parameter than rats exposed to SAL; *p<0.05.