Amplified Striatal Responses to Near-Miss Outcomes in Pathological Gamblers

Abstract

Near-misses in gambling games are losing events that come close to a win. Near-misses were previously shown to recruit reward-related brain regions including the ventral striatum, and to invigorate gambling behavior, supposedly by fostering an illusion of control. Given that pathological gamblers are particularly vulnerable to such cognitive illusions, their persistent gambling behavior might result from an amplified striatal sensitivity to near-misses. In addition, animal studies have shown that behavioral responses to near-miss-like events are sensitive to dopamine, but this dopaminergic influence has not been tested in humans. To investigate these hypotheses, we recruited 22 pathological gamblers and 22 healthy controls who played a slot machine task delivering wins, near-misses and full-misses, inside an fMRI scanner. Each participant played the task twice, once under placebo and once under a dopamine D2 receptor antagonist (sulpiride 400 mg), in a doubleblind, counter-balanced design. Participants were asked about their motivation to continue gambling throughout the task. Across all participants, near-misses elicited higher motivation to continue gambling and increased striatal responses compared with full-misses. Crucially, pathological gamblers showed amplified striatal responses to near-misses compared with controls. These group differences were not observed following win outcomes. In contrast to our hypothesis, sulpiride did not induce any reliable modulation of brain responses to near-misses. Together, our results demonstrate that pathological gamblers have amplified brain responses to near-misses, which likely contribute to their persistent gambling behavior. However, there is no evidence that these responses are influenced by dopamine. These results have implications for treatment and gambling regulation. INTRODUCTIONPathological gambling is a behavioral addiction with dramatic consequences including bankruptcy, unemployment, and relationship problems. The prevalence among college students has risen sharply in the past 10 years (Nowak and Aloe, 2014), while the rate of attempted suicide, approaching 20%, is higher than for any other addictive disorder (Bischof et al, 2015). Central to pathological gambling is the loss of control over gambling behavior and the inability to stop playing. This compulsive behavior is postulated to be fueled by cognitive distortions regarding the game structure. One example is the misappraisal of nearmiss events-losing outcomes that come close to a winwhich invigorate ongoing gambling behavior, conceivably by fostering an illusion of control (Clark, 2010). Although the behavioral vulnerability of pathological gamblers to such cognitive distortions is well established (Michalczuk et al, 2011), the underlying neural and neurochemical mechanisms remain elusive. We aimed to address this question using a combination of fMRI and pharmacological manipulation.Near-miss events are a hallmark of many gambling games and are particularly frequent in slot machines, which are recogniz...

Gambling disorder: an integrative review of animal and human studies

“…In humans, mesolimbic circuits have also been implicated in this type of cognitive distortion, with heightened activity seen in cortical mesolimbic regions during near‐miss events in fMRI studies . Furthermore, these increases are greater in GD individuals compared with controls . These imaging studies also reported stronger striatal–insula connections when gamblers had higher illusions of control .…”

“…179,180,185 Furthermore, these increases are greater in GD individuals compared with controls. 186 These imaging studies also reported stronger striatal-insula connections when gamblers had higher illusions of control. 187 Finally, the insula has also been strongly implicated in the processing of near-miss events.…”

Altered orbitofrontal sulcogyral patterns in gambling disorder: a multicenter study

“…A total of 177 pathological gamblers (PGs) and 169 healthy controls (HCs) were included in the present study. These data were pooled from nine separate previous neuroimaging studies 8,15,18,[43][44][45][46][47][48] (Supplementary Table 1). From this aggregated sample, 18 participants (10 PGs and 8 HCs) were excluded because of head movement artefacts on anatomical T1 scans preventing us from reliably identifying OFC sulcogyral patterns, and 4 participants (2 PGs and 2 HCs) were excluded because either demographic or diagnostic information was missing.…”

Gambling with Rose-Tinted Glasses on: Use of Emotion-Regulation Strategies Correlates with Dysfunctional Cognitions in Gambling Disorder Patients

“…For example, near-wins (loss events perceptually close to the jackpot; e.g., two dollar signs and a cherry aligned on the display of a slot machine) exert rewarding effects (Clark, Crooks, Clarke, Aitken, & Dunn, 2012; Clark, Lawrence, Astley-Jones, & Gray, 2009). Abnormal reaction to near-wins correlate with GDPs’ beliefs on the mastery of their instrumental or predictive skills, and, at the neurobiological level, is associated to BOLD signal in the ventral striatum, comparable to the one caused by true wins (Chase & Clark, 2010; Habib & Dixon, 2010; Sescousse et al., in press). In other words, up-regulating positive emotions could contribute, not only to gambling expectancies, but also to alter the mechanisms responsible for learning about appetitive aspects of gambling outcomes via, again, associative learning and causal attribution mechanisms.…”