Effects of cocaine on sensitivity to outcome devaluation and interaction with NAC treatment. (a) Mean (+SEM) lever presses across 2-day blocks of instrumental training. There were no group differences indicating equivalent performance in training. (b) Mean (+SEM) lever presses following outcome devaluation in groups treated with saline and 0, 60, or 120 mg/kg of NAC. All groups showed similar sensitivity to outcome devaluation, demonstrating that NAC alone had no detectable effect on devaluation. (c) Mean (+SEM) lever presses following outcome devaluation in groups treated with cocaine (30 mg/kg) along with 0, 60, or 120 mg/kg NAC. Animals receiving cocaine and 0 mg/kg were not sensitive to outcome devaluation, indicating that their performance was under habitual control. This effect was reversed when animals were cotreated with NAC (60 or 120 mg/kg). N=10–11 rats per group, *significant devaluation effect.