Gambling

More predictable it is, the closer in time DA moves to the reward rather than the CS.

When prediction isn’t certain, DA fires between the time of the presentation of CS and UCS. and more uncertainty, the more dopamine fires.

epxosure to uncertainty may increase the number of at-risk individuals

parkinson's and gambling

  • dopamine dysregualtion synrdome… wildly fluctating amount of DA, respond differentlially medication… they are of interest for thi slecture because their wildly fulctuating DA creates weild behavioural swings that wouldnt otherwise be observed

  • engage in pathological gambling, hypersexuality, food binging, stealing…

NEUR 453: Neurobiology of Motivated Behaviours - Lecture 9: Gambling

Outline

  • Background

  • Reward Uncertainty

  • Dopamine, Sensitization and Cues

  • Iowa Gambling Task (IGT)

  • Gambling Delusions

    • Gambler’s Fallacy

    • Delusion of control

    • Near-Miss

    • Losses Disguised as Wins

    • Priming and Risk Aversion

Background

Definitions & Prevalence

  • Terminology:

    • Currently referred to as Gambling Disorder (DSM-V).

    • Previous terms included Pathological Gambling (PG), Compulsive Gambling, and Problem Gambling.

  • Prevalence:

    • Approximately 1% of the adult population in the US has a severe gambling problem.

    • Around 6-9% of young people and young adults experience gambling-related problems, which is a higher rate than among adults.

    • Ethnic and racial minorities have higher rates of gambling problems.

  • Individuals with gambling issues often share many risk factors associated with other addictive behaviors, such as:

    • Other psychiatric disorders (e.g., depression).

    • An unstable home life.

    • Lack of peer or community support.

    • Statistic: 96.3% of lifetime pathological gamblers also met lifetime criteria for one or more other psychiatric disorders.

Rise of the Slot Machines

  • Compared to other gamblers, slot machine players:

    • Have the highest rate of bankruptcy.

    • Experience the fastest transition from social gambling (SG) to pathological gambling (PG).

    • Are the most likely to seek clinical treatment.

  • Statistics:

    • Approximately 72-86% of the US population participates in some form of gambling each year.

    • The annual costs of PG in the US are estimated to exceed $5 billion.

    • Americans spend over $37 billion annually on gambling, up from $28 billion in 2003.

Stress

  • Statistics:

    • About 40% of problem and pathological gamblers qualify for an anxiety disorder diagnosis (Lorains et al., 2011; Black & Moyer, 2014).

    • Only nicotine dependence, substance abuse disorder, and mood disorders are more prevalent among gamblers in these studies.

    • Gamblers reported higher rates of affective disorders (33.3%) compared to non-gamblers (14.2%) (Petry et al., 2005).

  • Physiological Effects of Gambling:

    • Gambling has been shown to increase cortisol levels and heart rate while playing blackjack at a casino (Meyer et al., 2000).

Gambling Disorder Discussion

  • Question: Is Gambling Disorder the same as other addictions, such as drug addiction?

    • Features shared and not shared:

    • Tolerance/withdrawal.

    • Sensitization.

    • Adverse consequences.

    • Chemical substance (drug/food).

  • Impairment Areas:

    • Social/family life, work, and health.

Gambling Research

  • Challenges in studying gambling:

    • It does not involve a consumable reward.

    • Methods for studying monetary reward and limitations in animal models.

  • Studying loss in gambling:

    • Withholding reward and timeouts.

  • Psychological principles can also be examined instead of imitating gambling processes.

Reward Uncertainty

Dopamine - Reward Prediction

  • Prediction Error Signal:

    • Unpredicted reward: increased dopamine (DA) firing to unconditioned stimulus/reward (UCS/R).

    • Predicted reward: DA firing to conditioned stimulus (CS).

    • Omitting a predicted reward results in DA firing to CS and a DA dip with absence of UCS.

Dopamine & Uncertain Reward

  • Known outcomes when reward is:

    • Unpredicted (probability p = 0.0): DA firing attributed to UCS.

    • Fully predicted (probability p = 1.0): DA firing attributed to CS.

  • What happens when the cue does not perfectly predict the outcome?

    • For probabilities between 0 and 1 (i.e., 0.0 < p < 1.0):

    • Firing shifts progressively from UCS to CS as probability increases.

    • Maximum firing occurs at p = 0.5 where uncertainty is greatest.

Gambling & Uncertainty

  • Uncertainty is fundamental in making games attractive (e.g., tic-tac-toe).

  • Reasons why uncertainty is appealing/motivating:

    • Foraging and survival aspects.

    • Activation of reward pathways during stress and anxiety.

    • Uncertainty enhances knowledge acquisition, thereby reducing risk.

  • Forms of uncertainty:

    • Probability (e.g., 100% vs. 50%).

    • Magnitude (e.g., small vs. large rewards).

    • Location and timing of rewards.

Reward Uncertainty and Cues

  • Cues predicting uncertain rewards are more attractive.

  • Combined probability and magnitude uncertainty increases sign-tracking in autoshaping tasks.

Uncertainty & Sign-Tracking

  • Exposure to uncertainty can increase the number of at-risk individuals:

    • Increased sign-trackers and decreased goal-trackers.

    • Attribution of ‘wanting’ to reward cues may be enhanced.

Uncertainty & Sensitization

  • Not knowing when a win may occur can become rewarding itself.

  • Sensitization of reward pathways due to exposure to gambling behaviors.

  • Animals are exposed to different reward ratios (Fixed Ratio (FR) and Variable Ratio (VR)).

    • VR refers to a range from 1 to 2 times the reward.

    • Results in locomotor sensitization in response to AMPH (amphetamine).

Gambling, Dopamine, & Cross-Sensitization

  • Pathological Gamblers (PG) exhibit greater spikes in DA levels in response to AMPH than Healthy Controls (HC), especially in:

    • Striatum (increased by 54-63%) and midbrain regions.

  • DA response in PG correlates with the severity of gambling behavior:

    • Suggestively indicating a possible cross-sensitization effect between gambling and amphetamines.

  • These findings challenge the validity of the reward deficiency hypothesis in pathological gambling; rather than being deficient in DA, they exhibit a greater response.

Parkinson’s Disease & Gambling

  • Treatment with dopaminergic medications in certain populations, such as patients with Parkinson’s disease (PD), can result in a Dopamine Dysregulation Syndrome (DDS).

  • Manifestations of DDS include:

    • Compulsive drug usage, pathological gambling, hypersexuality, food binging, etc.

  • Examples include:

    • In 7 PD patients, PG developed within three months following treatment initiation or dose escalation.

    • In another four cases, PG resolved after discontinuing the agonist.

  • Patients with DDS show sensitized DA responses in the ventral striatum upon treatment with levodopa compared to those without DDS.

NAc & Uncertain Decisions

  • Experimental setup: Rats choose between 1 certain pellet or 4 uncertain pellets by changing probability settings.

  • Rats with lesions in the Nucleus Accumbens (NAc) Core (AcbC) displayed risk-averse behavior, resulting in less food intake compared to control rats.

  • Suggests that NAc promotes choices favoring uncertain outcomes.

Loss & Uncertainty

  • Pathological gamblers make more bets than choices with certain outcomes compared to control participants.

  • Knowledge of winning odds does not significantly influence PG's gambling decisions but reduces betting behaviors in controls.

  • PGs exhibit stronger brain activation while anticipating high-uncertain monetary rewards compared to lower-certain rewards.

  • Losses may trigger greater reward-seeking behaviors via DA release in PGs, further complicating the understanding of causality.

Gambling Craving & Cues

Experimental Investigation

  • Study involving 48 university student gamblers assessed acute gambling cravings when presented with cues:

    • Types of cues: Imagery scripts describing gambling vs. photographs of gambling-related stimuli.

  • Self-reported cravings significantly increased following exposure to both cue types, with imagery scripts eliciting a more significant effect.

  • Similarities to substances of abuse indicate that cues related to gambling trigger craving and may lead to relapse.

Environmental Factors

  • Investigated whether the gambling environment has an impact on gambling behavior.

    • Findings showed that flashing lights significantly increased participants’ intent to gamble, while static lighting produced the opposite effect.

Game Characteristics and Player Perception

  • Studies examining the impact of sound in games indicate:

    • Games with winning sounds are preferred and increase win estimates.

    • Sounds can cause players to overestimate their winnings on slot machines.

Loss Chasing

  • Pathological gamblers often engage in “chasing one’s losses,” continuing to gamble despite financial losses.

  • Evidence shows that PGs who experience losses exhibit significantly increased DA release in the left ventral striatum compared to HCs.

  • In contrast, there is no difference in DA release between PG and HC when winning occurs.

  • Losses seem to drive further reward-seeking behavior through DA release in PGs, with considerations of whether this is a cause or consequence.

Gambling for Pleasure: Opioids

  • Research shows PGs exhibit significant blunting of opioid release when compared to Healthy Volunteers (HV).

  • Blunted responses to amphetamine-induced euphoria and alertness in PG suggest a possible reduction in the sensation of ‘liking’, supporting evidence that dysregulation of endogenous opioids may contribute to addiction pathology.

Iowa Gambling Task (IGT)

Overview

  • A computer-simulated decision-making task allowing participants to choose between 4 decks labeled as good and bad.

Deck Designations

  • Good Decks (C & D):

    • Provide small wins and small losses leading to long-term gain.

  • Bad Decks (A & B):

    • Provide large wins but also larger losses leading to long-term loss.

Learning Outcomes

  • Healthy controls (HC) learn to select good decks over time, while patients with amygdala (AMYG) or ventromedial prefrontal cortex (vmPFC) lesions tend to prefer bad decks.

  • Pathological Gamblers show a strong preference for choices featuring high rewards with associated higher losses during the IGT, attributed to a hypersensitivity for large monetary gains, reflecting enhanced reward system engagement.

Decision-making Behaviour in PG

  • Similarities identified between the decision-making behaviors of PG and patients with vmPFC lesions:

    • PG patients more frequently select from disadvantageous decks, with worsening effects over time.

  • Proposed explanation involves diminished ability to evaluate future consequences, potentially linked to abnormal functioning of the orbitofrontal cortex (OFC).

Neurobiological Correlations

  • PG individuals demonstrating increased DA release in the ventral striatum exhibited greater excitement, irrespective of performance on the task.

  • A significant correlation exists between DA release and excitement levels in PGs but not in HCs.

Non-Pathological Gamblers

  • Impairments in the IGT are not limited to PGs; non-pathological lottery gamblers also exhibit:

    • Reduced net gains and greater losses due to lesser selection of advantageous decks and an inability to adapt over time compared with matched controls.

Rat Gambling Task (rGT)

Overview

  • The Iowa Gambling Task has been adapted for use in rats.

Key Findings

  • Animals with AMYG lesions tend to make riskier choices.

  • Inactivation of the prelimbic cortex (PLC) and infralimbic cortex (ILC) appears to increase selection of disadvantageous options.

Gambling Delusions

Types of Gambling Delusions

  • Gambler’s Fallacy:

    • Belief that past outcomes affect future outcomes despite being independent events (e.g., thinking a win is 'due' after a series of losses).

  • Delusion of Control:

    • Belief of possessing a strategy to influence odds that are, in fact, random.

  • Near-Miss Effect:

    • The experience of almost winning increases motivation to gamble despite the actual loss.

  • Losses Disguised as Wins:

    • The design of slot machines allows for the perception of winning even when losses occur, thus misleading players.

  • Risk Aversion and Priming Effects:

    • Past winning memories can provoke risky behavior in subsequent betting situations.

Empirical Evidence for Gambling Delusions

  • Studies involving roulette games highlighted gambler’s fallacy with normal subjects exhibiting fallacious reasoning based on prior runs.

  • Insula Role:

    • Patients with insula lesions did not exhibit gambler's fallacy, while controls and those with lesions in other brain regions did.

  • Near-miss effects generated elevated motivation to gamble following near-miss outcomes in healthy individuals and those with lesions in other regions, suggesting cognitive distortions linked to insula activity.

Emotional Responses and Near-Miss Outcomes

  • Near-miss scenarios signal progress on a task, creating feelings of control and enhancing motivation to continue gambling.

  • Some studies noted:

    • Participants report increased chances of winning following near-miss events, particularly when they were directly controlling the gambling activity.

Psychological Mechanisms Behind Near-Miss Effects

  • Cognitive Distortions Resulting from Near-Misses:

    • Though less pleasant than full wins, near-miss outcomes can elevate the desire to continue, activating brain areas related to reward and motivation, such as the striatum and anterior cingulate cortex (ACC).

    • Physiological measures indicate that near misses elicit high arousal comparable to win outcomes, and gambling severity is associated with heightened DA midbrain responses to near-misses.

Animal Models of Near-Miss Phenomena

  • Experimental setups with rats mimicking slot machine mechanics show varying responses to reward sequences indicating their recognition of reward structure based on multi-light signals.

  • Studies indicate limitations in animal cognition concerning adaptive behaviors expected in gambling scenarios.

Losses Disguised as Wins (LDWs)

  • Types of Slot Machines:

    • Single Line: Features three reels with only one pay line.

    • Multi-Line: Allows for bets across several lines, increasing opportunity for perceived wins.

Implications of Multi-line Slot Machines

  • Participants favored multi-line formats, often misclassifying losses as wins due to misleading win celebration sounds which inflate perceived winning rates and create more robust gaming experiences.

  • Statistical analysis highlights:

    • Payback percentages were similar across slot types, yet players wagered significantly more and experienced larger emotional responses.

    • Multi-line machines generated more perceived wins despite actual losses, emphasizing the cognitive error in interpreting gambling results.

Risk Seeking vs. Risk Aversion

  • Inquiry into player preferences between guaranteed lower payoffs vs. higher risks has shown a tendency towards conservatism in financial choices.

  • Memory of past wins or experiences plays a substantial role in influencing decisions, lending itself to potential manipulations linked to gambling tendencies.

The Role of Priming

  • Use of different primes (e.g., the value of fruits associated with gambling outcomes) showcases variance in risk behavior and cognitive distortions linked to anticipated outcomes.

  • Priming results indicate natural risk aversion, although specific high-value primes can shift decisions to favor risk.

Points to Consider

  • Current research underscores that perceived risks in games like online poker or slot machines may not be as delineated as previously believed; promising therapies for gambling disorder include CBT and motivational interviewing.

  • Approximately one-third of individuals with gambling problems may recover without formal interventions.

Conclusion

  • Calls for societal reflection on gambling's portrayal and regulation suggest that structural changes to gambling environments (e.g., reduction of flashing lights) may mitigate addictive behaviors.

  • Preparing for the next session, the focus will shift to Lecture 10: Aggression.