Abstract
Disinhibition over drug use, enhanced salience of drug use and decreased salience of natural reinforcers are thought to play an important role substance dependence. Whether this is also true for pathological gambling is unclear. To understand the effects of affective stimuli on response inhibition in problem gamblers (PRGs), we designed an affective Go/Nogo to examine the interaction between response inhibition and salience attribution in 16 PRGs and 15 healthy controls (HCs).Four affective blocks were presented with Go trials containing neutral, gamble, positive or negative affective pictures. The No-Go trials in these blocks contained neutral pictures. Outcomes of interest included percentage of impulsive errors and mean reaction times in the different blocks. Brain activity related to No-Go trials was assessed to measure response inhibition in the various affective conditions and brain activity related to Go trials was assessed to measure salience attribution.PRGs made fewer errors during gamble and positive trials than HCs, but were slower during all trials types. Compared to HCs, PRGs activated the dorsolateral prefrontal cortex, anterior cingulate and ventral striatum to a greater extent while viewing gamble pictures. The dorsal lateral and inferior frontal cortex were more activated in PRGs than in HCs while viewing positive and negative pictures. During neutral inhibition, PRGs were slower but similar in accuracy to HCs, and showed more dorsolateral prefrontal and anterior cingulate cortex activity. In contrast, during gamble and positive pictures PRGs performed better than HCs, and showed lower activation of the dorsolateral and anterior cingulate cortex.This study shows that gambling-related stimuli are more salient for PRGs than for HCs. PRGs seem to rely on compensatory brain activity to achieve similar performance during neutral response inhibition. A gambling-related or positive context appears to facilitate response inhibition as indicated by lower brain activity and fewer behavioural errors in PRGs.
Highlights
Pathological gambling is characterized by persistent and recurrent maladaptive gambling behaviour (American Psychiatric Association 2003)
problem gamblers (PRGs) showed more activity in regions associated with salience attribution compared to healthy controls (HCs) on Gamble Go vs. Neutral Go: left dorsolateral prefrontal cortex (DLPFC), right ventral striatum, and right ACC ( Figure 3)
Problem gamblers show enhanced salience to gambling and positive pictures Congruent with our hypothesis regarding salience attribution towards gambling pictures in PRGs, we found that PRGs who were confronted with gambling related cues versus neutral pictures showed increased DLPFC, ACC and ventral striatum activation compared to HCs
Summary
Pathological gambling is characterized by persistent and recurrent maladaptive gambling behaviour (American Psychiatric Association 2003). An influential and empirically grounded neurobiological model for substance dependence, the Impaired Response Inhibition and Salience Attribution (I-RISA) model, postulates that repeated drug use triggers a series of adaptations in neuronal circuits involved in memory, motivation, and cognitive control. If an individual has used drugs, memories of this event are stored as associations between the stimulus and the elicited positive (pleasant) or negative (aversive) experiences, facilitated by dopaminergic activation caused by the drug of abuse. This results in an enhanced (and long-lasting) salience for the drug and its associated cues at the expense of decreased salience for natural reinforcers [1]. The IRISA model is based on findings in substance dependent subjects, converging evidence suggests that this model could explain the development and course of pathological gambling [2,3,4]
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