to learn reversals, even though they learn initial contingencies at a normal rate (Schoenbaum et al. 2004; Calu et al. 2007). Lesions of the frontal cortex cause reversal learning deficits in tasks similar to chronic drug abuse induced deficits (Schoenbaum et al. 2006). Studies of both human cocaine and alcohol addicts have found dysfunctional decision making in tasks involving delaying reward for more value and reversal learning tasks that probe cognitive flexibility and frontal lobe function (Bechara et al. 2002). The persistence of addiction, a chronic relapsing disorder, compares with the persistence in innate immune gene induction (Qin et al. 2007; Qin et al. 2008) and loss of behavioral flexibility.
