Reward-system effect and “left hemispheric unbalance”: a comparison between drug addiction and high-BAS healthy subjects on gambling behavior

Reward-system effect and “left hemispheric unbalance”: a comparison between drug addiction and high-BAS healthy subjects on gambling behavior Roberta Finocchiaro 1, 2 - Michela Balconi 1, 2 *    Research Unit in Affective and Social Neuroscience, Catholic University of the Sacred Heart, Milan, Italy 2 Department of Psychology, Catholic University of the Sacred Heart, Milan, Italy 1 doi: 10.7358/neur-2015-017-fino Abstract Recent studies show the similarity of reward-related neurocircuitry and behavioral patterns between pathological gamblers and substance addictive patients. Evidences proved that pathological gambling (PG) and Substance Use Disorders (SUD) are associated with deficits in frontal lobe function and that they show similar behaviors to that of patients with bilateral VMPFC lesions. The present article aimed to compare the results of two studies concerning the relationship between the Behavioral Activation System (BAS) and the hemispheric lateralisation effect that supports the gambling behavior in addiction disease. In the two studies we considered a group of Cocaine Addictive (CA) patients and high-BAS healthy subjects who were tested using the Iowa Gambling Task. Also metacognitive questionary and alpha band modulation were considered. It was found that the “left hemisphere unbalance” may be considered as a critical marker of dysfunctional decision-making in addictive behaviors (drug addiction and gambling behaviours) and a factor able to explain the tendency to opt in favor of more reward-related conditions. Keywords: Addiction; Iowa Gambling Task; Alpha brain oscillation; BAS * The authors have no competing financial interest, potential conflict of interest, or financial relationship with commercial entities to report. Neuropsychological Trends – 17/2015 http://www.ledonline.it/neuropsychologicaltrends/ 37 Roberta Finocchiaro - Michela Balconi 1. Introduction Compulsive addictive behavior can be described as a condition associated with dysfunctional brain mechanisms that subvert the ability to make decisions (Barry & Petry, 2008). Recent models in the neuropsychological domain proposed that maladaptive substance use could arise from poor decision-making skills that lead individuals with Substance Use Disorders (SUD) to ignore long-term negative consequences in the interest of immediate gratification or relief of uncomfortable states (Allen, Moeller, Rhoades & Cherek, 1998; Barry & Petry, 2008; Mitchell, Banaji & MacRae, 2005). It was found in a sample of SUD patients that they prefered to opt in favour of immediate reward, without considering the long-term outcomes, and that they showed impaired metacognitive representation (self-knowledge; strategic planning; flexibility; efficacy) of the decisional behavior (Balconi, Finocchiaro & Canavesio, in press; 2014). About the reward mechanisms, the Behavioral Activation System (BAS) / Behavioral Inhibition System (BIS) measure, based on Gray’s Model (Gray, 1981; Carver & White, 1994), represents a usable tool to test this reward-sensitivity (Balconi, Falbo & Conte, 2012; Yu & Dayan, 2009). The BAS was conceptualized as a motivational system that is sensitive to signals of reward (approach behavior) in contrast of BIS that is sensitive to signals of punishment (withdrawal behavior). Previous research found the neuroanatomical correlates of BIS/ BAS system; in particular the left prefrontal cortex (PFC) was shown to be implicated in approach-related motivations and emotions and mediated by dopaminergic system, instead the right PFC was found to be involved in withdrawal-related motivations and emotions (Gray & McNaughton, 2000). A direct association between the BAS and BAS subscales (Drive, Fun Seeking and Reward Responsiveness) to substance abuse has been shown (Colder & O’Connor, 2002) and it may be considered predictive of substance abuse (Franken, Muris & Georgieva, 2006). From the brain cortical view, resting EEG studies have shown that frontal hemispheric asymmetry in favor of the left PFC reflects an individual predisposition to respond in terms of withdrawal-related behavior (Balconi & Bortolotti, 2012; Davidson, 2004; Harmon-Jones, 2004), and a left unbalance effect (increasing activation of alpha band oscillations) was found during the IGT in SUD patients (Balconi, Finocchiaro & Canavesio, 2014). Both approach- and withdrawal-motivations are paralleled by the reward and punishment contingencies, and the IGT (Bechara, Damasio, Damasio & Anderson, 1994) is argued to be capable of indexing punishment-reward conditions, since decisions become motivated by inherent punishment and reward schedules. It would be hypothesizable that the hemispheric “unbalance” between the Neuropsychological Trends – 17/2015 http://www.ledonline.it/neuropsychologicaltrends/ 38 Reward-system effect and “left hemispheric unbalance” left and right frontal side would characterize the subjects’ category which shows a higher reward attitude, with or without addiction. Recent studies revealed that pathological gambling is associated with deficits in frontal lobe function and that pathological gambler subjects show similar behavior to that of patients with bilateral VMPFC lesions (Bechara, Damasio, Damasio & Anderson, 1994; Balodis et al., 2012) and SUD patients (Balconi, Finocchiaro & Canavesio, 2014). The dysfunctional behavior in decisionalprocesses could be caused by substance abuse or pathological gambling behavior yield risk-seeking, high dependence to reward which produces more risky and unfunctional (loss) strategies. Thus we compared two studies (Balconi, Finocchiaro & Canavesio, 2014; Balconi, Finocchiaro, Canavesio & Messina, 2014) that focused on brain cortical oscillation (alpha band analysis) in the groups of high-reward related individuals including Cocaine Addictive and high-BAS healthy subjects during IGT performance. In association with riskier choices, Cocaine Addictive and high-BAS healthy subjects in comparison to control group (low-BAS subjects) should show a consistent alpha activity increasing within the left hemisphere in case of an immediate reward (disadvantageous decks, DD) in comparison with a delayed reward (advantageous decks, AD). We supposed that a similar profile for both groups (CA patients and high-BAS subjects) can explain the dysfunctional behavior on the decisional-making task. 2. Methods The CA group included 40 individuals of the first study (who were all patients of the Drug Dependence Department (SerT 1 Milano - SerT 2 Monza) (mean age = 55.3; SD = 4.33). Inclusion criteria were: lifetime history of dependence based on responses to the Structural Clinical Interview for DSM IV (SCID) (First, Spitzer, Gibbon & Williams, 1997); the interview was use to evaluate the severity of drug abuse by: Intensity (average dosing); Frequency (consumption episodes by month); Duration (years of duration); Minimum abstinence duration of 15 days before any testing. A control group (CG) was compa (...truncated)