12. Left hemispheric “unbalance” (Alpha Band) and decisional bias in drug addiction – The role of the reward system

The current research explored the impact of cortical frontal asymmetry (left-lateralization effect of alpha frequency band) and Behavioral Activation System (BAS) on Substance Use Disorder (SUD) in decisional processes using the Iowa Gambling Task (IGT). Thus gambling behavior was considered in SUD. Forty SUD participants and forty-two controls (CG) were tested using the IGT. Behavioral responses (gain/loss options), BIS/BAS scores and lateralized alpha band modulation (LTA) were considered. The SUD group increased the tendency to opt in favor of the immediate reward (loss strategy) more than the long-term option (win strategy) compared to the CG. Secondly, higher reward-subscale scores were observed in SUD. Thirdly, SUD showed an increase in left-hemisphere activation in response to losing (with immediate reward) choices in comparison with the CG. An imbalanced left hemispheric effect related to higher BAS trait could explain this “reward bias,” because these components were found to affect (through the regression analysis) the main behavioral deficits. Lateralization effect and BAS may explain the gambling behavior in SUD.