Reward-system effect (BAS rating), left hemispheric “unbalance” (alpha band oscillations) and decisional impairments in drug addiction

The present research explored the impact of cortical frontal asymmetry (left-lateralization effect) and BAS (Behavioral Activation System) contribution in Substance Use Disorder (SUD) in decisional processes (IOWAS Gambling Task) (IGT). Forty SUD participants and forty-two controls (CG) were tested using 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, high-BAS scores (mainly for BAS-Reward subscale) were observed in SUD. Thirdly, SUD showed an increased lefthemisphere activation in response to losing (with immediate reward) choices in comparison with the CG. An imbalanced left hemispheric effect in concomitance with higher BAS attitude were supposed to explain this “reward bias”, since they were found to explain (regression analysis) the main behavioral deficits.