What motivates gambling behavior? Insight into dopamine's role

It is commonly believed that monetary gain is the cause of gambling behavior in humans. Mesolimbic dopamine (DA), the chief neuromediator of incentive motiva-tion, is indeed released to a larger extent in pathological gamblers (PG) than in healthy controls (HC) during gambling episodes (Linnet et al., 2011; Joutsa et al., 2012), as in other forms of compulsive and addictive behavior. However, recent find-ings indicate that the interaction between DA and reward is not so straightforward (Blum et al., 2012; Linnet et al., 2012). In PG andHC, DA release seems to reflect the unpredictability of reward delivery rather than reward per se. This suggests that the motivation to gamble is strongly (though not entirely) determined by the inability to predict reward occurrence. Here we dis-cuss several views of the role of DA in gambling, and attempt to provide an evo-lutionary framework to explain its role in uncertainty.