the nucleus accumbens.73,74 Differential regional changes in nicotinic receptor function in the nucleus accumbens and ventral tegmental area in nicotine, alcohol, and other addictions have also been reported, implicating α4β2 nicotinic receptor subtypes.19,44 Such decreases in reward system function might persist in the form of long-term biochemical changes that contribute to the clinical syndrome of acute withdrawal and protracted abstinence and could also explain the loss of interest in normal, non-drug rewards (ie, narrowing of the behavioural repertoire toward drugs and drug-related stimuli; tables 1, 2, circuit 5).
