Irrational beliefs, biases and gambling: Exploring the role of animal models in elucidating vulnerabilities for the development of pathological gambling

The Cultural Evolution of Games of Chance : A Historical Investigation of Chinese Gambling

Chance-based gambling has been a recurrent cultural activity throughout history and across many diverse human societies. In this paper, I combine quantitative and qualitative data and present a cultural evolutionary framework to explain why the odds in games of chance in premodern China appeared "designed" to ensure a moderate yet favorable house advantage. This is especially intriguing since extensive research in the history of probability has shown that, prior to the development of probability theory, people had very limited understanding of the nature of random events and were generally disinclined to think mathematically about the frequency of their occurrence. I argue that games of chance in the context of gambling may have culturally evolved into their documented forms via a process of selective imitation and retention, and neither the customers nor the gambling houses understood the probability calculus involved in these games.

A critical review of risk-sensitive foraging

Foraging is risk sensitive if choices depend on the variability of returns from the options as well as their mean return. Risk-sensitive foraging is important in behavioural ecology, psychology and neurophysiology. It has been explained both in terms of mechanisms and in terms of evolutionary advantage. We provide a critical review, evaluating both mechanistic and evolutionary accounts. Some derivations of risk sensitivity from mechanistic models based on psychophysics are not convincing because they depend on an inappropriate use of Jensen's inequality. Attempts have been made to link risk sensitivity to the ecology of a species, but again these are not convincing. The field of risk-sensitive foraging has provided a focus for theoretical and empirical work and has yielded important insights, but we lack a simple and empirically defendable general account of it in either mechanistic or evolutionary terms. However, empirical analysis of choice sequences under theoretically motivated experimental designs and environmental settings appears a promising avenue for mapping the scope and relative merits of existing theories. Simply put, the devil is in the sequence.

The Dimensional Structure of the Gambling Attitudes and Beliefs Survey: Challenging the Assumption of the Unidimensionality of Gambling-Specific Cognitive Distortions

The aim of the present study was to examine the dimensional structure of the Gambling Attitudes and Beliefs Survey (GABS). The GABS was administered to a sample of 415 individuals with self-reported problem or pathological gambling who were taking part in two different treatment studies preregistered with the German Clinical Trials Register (DRKS00013888) and ClinicalTrials.gov (NCT03372226). Exploratory factor analyses revealed a three-factor structure. We labeled the factors sensation seeking/illusion of control, luck/gambler's fallacy, and attitude/emotions. Subsequent confirmatory factor analyses proved the three-factor model superior to the one-factor model proposed by the developers of the GABS. All dimensions were significantly correlated with symptom severity scores. Group comparisons showed significantly higher factor scores on the first factor (sensation seeking/illusion of control) for individuals reporting both skill-based and chance-based gambling compared to those reporting only chance-based gambling. The present study questions the unidimensionality of the GABS. A multidimensional assessment of gambling-related cognitive biases, beliefs, and positively valued attitudes may be useful in determining treatment outcomes and goals and in the development of novel interventions.

The Relationship between Impulsiveness, Self-Esteem, Irrational Gambling Belief and Problem Gambling Moderating Effects of Gender

The present study investigated the relationship between impulsivity, self-esteem, irrational gambling belief, and problem gambling and also explored whether the relationships between these constructs are different for males and females. Participants included 563 college students with 259 males (46.0%) and 304 females (54.0%) from Korea. Participants completed a survey. The results showed that 5.3% of students were problem gamblers, while 9.4% were moderate-risk gamblers. The relationships between impulsivity, self-esteem, irrational gambling belief, and problem gambling differed for males and females. For females, greater impulsivity and lower self-esteem predicted higher irrational gambling belief, while higher irrational gambling belief predicted more problem gambling. For males, greater impulsivity predicted higher irrational gambling belief, and higher irrational gambling belief predicted more problem gambling. This finding suggests that different prevention efforts are needed, which will require identifying the variables that affect problem gambling.

Decision making and framing effects in multiple sclerosis

BACKGROUND

Previous studies reported reduced decision-making abilities for patients with multiple sclerosis (MS) relative to healthy controls (HC). This study aimed to evaluate whether these problems arise when sampling information or when pondering about the evidence collected.

METHODS

In a cross-sectional, controlled study, 43 relapsing-remitting MS patients (RRMS; Expanded Disability Status Scale 1.5, range 0-4) and 53 HC performed an information sampling task ('beads task'), a health-related framing task, and neuropsychological background tests.

RESULTS

In the beads task, patients collected as much information as HC prior to a decision. However, there were twice as many patients as HC making irrational decisions, that is, decisions against the evidence collected (RRMS: 26/43, 60%; HC: 16/53, 30%; p = 0.003). Compared to HC, patients also showed a stronger framing effect, that is, they were more strongly biased by the way health-related information was presented (p < 0.05, Cohen's d = 0.5). Overall, the framing effect predicted whether a participant would make irrational decisions (OR 2.12, 95% CI 1.29-3.49, p < 0.001).

CONCLUSIONS

Predecisional information sampling is intact in RRMS. However, compared to HC, patients are more likely to make irrational decisions and to be biased by the way health-related information is framed. This warrants caution in communication, especially in the medical context, with patients.

The role of opioidergic system in modulating cost/benefit decision-making in alcohol-preferring AA rats and Wistar rats

Research has highlighted the association of a positive family history of alcoholism with a positive treatment response to opioid antagonists in those with a gambling disorder. However, the role of the opioidergic system in gambling behavior is not well understood, and preclinical studies are needed to clarify this. In this study, Alko Alcohol (AA) and Wistar rats went through operant lever pressing training where the task was to choose the more profitable of two options. Different sized sucrose rewards guided the lever choices, and the probability of gaining rewards changed slowly to a level where choosing the smaller reward was the most profitable option. After training, rats were administered subcutaneously with opioid agonist morphine or opioid antagonist naltrexone to study the impact of opioidergic mechanisms on cost/benefit decisions. No difference was found in the decision-making between AA rats or Wistar rats after the morphine administration, but control data revealed a minor decision enhancing effect in AA rats. Naltrexone had no impact on the decisions in AA rats but promoted unprofitable decisions in Wistar rats. Supporting behavioral data showed that in both rat strains morphine increased, and naltrexone decreased, sucrose consumption. Naltrexone also increased the time to accomplish the operant task. The results suggest that opioid agonists could improve decision-making in cost-benefit settings in rats that are naturally prone to high alcohol drinking. The naltrexone results are ambiguous but may partly explain why opioid antagonists lack a positive pharmacotherapeutic effect in some subgroups of gamblers.

Feasibility, Acceptance, and Safety of Metacognitive Training for Problem and Pathological Gamblers (Gambling-MCT): A Pilot Study

Approximately 90% of problem and pathological gamblers remain untreated. This treatment gap may be diminished by the implementation of low-threshold treatment programs. As cognitive distortions play a crucial role in the development and maintenance of gambling problems, interventions targeting gambling-related biases may be particularly effective. The aim of the present study was to examine the feasibility, acceptance, and safety of a novel metacognitive training for individuals with gambling problems (Gambling-MCT). Twenty-five participants were included in an uncontrolled pilot trial with two assessment points (intervention). The intervention comprised eight training modules targeting gambling-specific cognitive distortions. At baseline and post assessment, symptom severity, as measured with the PG-YBOCS, and gambling-related cognitive distortions, as measured with the GABS, were assessed. In addition, interim assessments measuring session-specific changes were conducted. Subjective appraisal was examined after each module and also post treatment. On average, participants took part in 4.16 (SD = 2.84) training sessions. Both intent-to-treat and per protocol analyses showed significant improvements on the PG-YBOCS and the GABS (d_z = 0.37–1.37). After Bonferroni correction for multiple testing, linear mixed models for the analysis of session-specific changes showed no deterioration in participants’ mental state after any of the modules. Subjective appraisal of Gambling-MCT was good. The present pilot study provides first evidence for the feasibility, acceptance, and safety of Gambling-MCT. Recruitment of participants remains challenging, emphasizing the importance of overcoming patient-related treatment barriers. Future studies need to investigate the efficacy of Gambling-MCT in randomized controlled trials.

Impaired decision making following escalation of cocaine self-administration predicts vulnerability to relapse in rats

Impairments in cost‐benefit decision making represent a cardinal feature of drug addiction. However, whether these alterations predate drug exposure, thereby contributing to facilitating loss of control over drug intake, or alternatively arise as a result of drug use and subsequently confer vulnerability to relapse has yet to be determined. Male Sprague‐Dawley rats were trained to self‐administer (SA) cocaine during 19 daily long‐access (12‐h) sessions; conditions reliably shown to promote escalation. One week after cocaine SA, rats underwent an extinction/relapse test immediately followed by conditioned stimuli–, stress‐, and drug‐primed reinstatement challenges. The influence of escalated cocaine intake on decision making was measured over time by four test sessions of a rodent analogue of the Iowa Gambling Task (rGT), once prior to cocaine exposure and then 1 day, 1 week, and 1 month after the last SA session. Substantial individual variability was observed in the influence of escalated cocaine SA on decision‐making performance. A subset of rats displayed pronounced deficits, while others showed unaffected or even improved performance on the rat Gambling Task (rGT) 24 hours after the last SA session. When challenged with a relapse test after 1 week of forced abstinence, animals that showed impaired decision making following SA displayed an increased propensity to respond for cocaine under extinction. These data suggest that decision‐making deficits in individuals with drug addiction are not antecedent to—but arise as a consequence of—drug exposure. Moreover, these data indicate that susceptibility to the deleterious effects of drugs on decision making confers vulnerability toward relapse.

Pre-clinical models of reward deficiency syndrome: A behavioral octopus

Individuals with mood disorders or with addiction, impulsivity and some personality disorders can share in common a dysfunction in how the brain perceives reward, where processing of natural endorphins or the response to exogenous dopamine stimulants is impaired. Reward Deficiency Syndrome (RDS) is a polygenic trait with implications that suggest cross-talk between different neurological systems that include the known reward pathway, neuroendocrine systems, and motivational systems. In this review we evaluate well-characterized animal models for their construct validity and as potential models for RDS. Animal models used to study substance use disorder, major depressive disorder (MDD), early life stress, immune dysregulation, attention deficit hyperactivity disorder (ADHD), post traumatic stress disorder (PTSD), compulsive gambling and compulsive eating disorders are discussed. These disorders recruit underlying reward deficiency mechanisms in multiple brain centers. Because of the widespread and remarkable array of associated/overlapping behavioral manifestations with a common root of hypodopaminergia, the basic endophenotype recognized as RDS is indeed likened to a behavioral octopus. We conclude this review with a look ahead on how these models can be used to investigate potential therapeutics that target the underlying common deficiency.

Gambling disorder

Gambling disorder is characterized by a persistent, recurrent pattern of gambling that is associated with substantial distress or impairment. The prevalence of gambling disorder has been estimated at 0.5% of the adult population in the United States, with comparable or slightly higher estimates in other countries. The aetiology of gambling disorder is complex, with implicated genetic and environmental factors. Neurobiological studies have implicated cortico-striato-limbic structures and circuits in the pathophysiology of this disorder. Individuals with gambling disorder often go unrecognized and untreated, including within clinical settings. Gambling disorder frequently co-occurs with other conditions, particularly other psychiatric disorders. Behavioural interventions, particularly cognitive-behavioural therapy but also motivational interviewing and Gamblers Anonymous, are supported in the treatment of gambling disorder. No pharmacological therapy has a formal indication for the treatment of gambling disorder, although placebo-controlled trials suggest that some medications, such as opioid-receptor antagonists, may be helpful. Given the associations with poor quality of life and suicide, improved identification, prevention, policy and treatment efforts are needed to help people with gambling disorder.

Increased motor impulsivity in a rat gambling task during chronic ropinirole treatment: potentiation by win-paired audiovisual cues

RATIONALE

Chronic administration of D_2/3 receptor agonists ropinirole or pramipexole can increase the choice of uncertain rewards in rats, theoretically approximating iatrogenic gambling disorder (iGD).

OBJECTIVES

We aimed to assess the effect of chronic ropinirole in animal models that attempt to capture critical aspects of commercial gambling, including the risk of losing rather than failing to gain, and the use of win-paired sensory stimuli heavily featured in electronic gambling machines (EGMs).

METHODS

Male Long-Evans rats learned the rat gambling task (rGT; n = 24), in which animals sample between four options that differ in the magnitude and probability of rewards and time-out punishments. In the cued rGT (n = 40), reward-concurrent audiovisual cues were added that scaled in complexity with win size. Rats were then implanted with an osmotic pump delivering ropinirole (5 mg/kg/day) or saline for 28 days.

RESULTS

Chronic ropinirole did not unequivocally increase preference for more uncertain outcomes in either the cued or uncued rGT. Ropinirole transiently increased premature responses, a measure of motor impulsivity, and this change was larger and more long-lasting in the cued task.

CONCLUSIONS

These data suggest that explicitly signaling loss prevents the increase in preference for uncertain rewards caused by D_2/3 receptor agonists observed previously. The ability of win-paired cues to amplify ropinirole-induced increases in motor impulsivity may explain why compulsive use of EGMs is particularly common in iGD. These data offer valuable insight into the cognitive-behavioral mechanisms through which chronic dopamine agonist treatments may induce iGD and related impulse control disorders.

Review: brain neurobiology of gambling disorder based on rodent models

Different literature reviews of gambling disorder (GD) neurobiology have been focused on human studies, others have focused on rodents, and others combined human and rodent studies. The main question of this review was: which are the main neurotransmitters systems and brain structures relevant for GD based on recent rodent studies? This work aims to review the experimental findings regarding the rodent´s neurobiology of GD. A search in the Pub Med database was set (October 2012-October 2017) and 162 references were obtained. After screening, 121 references were excluded, and only 41 references remained from the initial output. More, other 25 references were added to complement (introduction section, neuroanatomical descriptions) the principal part of the work. At the end, a total of 66 references remained for the review. The main conclusions are: 1) according to studies that used noninvasive methods for drug administration, some of the neurotransmitters and receptors involved in behaviors related to GD are: muscarinic, N-methyl-D-aspartate (NMDA), cannabinoid receptor 1 (CB₁), cannabinoid receptor 2 (CB₂), dopamine 2 receptor (D₂), dopamine 3 receptor (D₃), and dopamine 4 receptor (D₄); 2) moreover, there are other neurotransmitters and receptors involved in GD based on studies that use invasive methods of drug administration (eg, brain microinjection); example of these are: serotonin 1A receptor (5-HT_1A), noradrenaline receptors, gamma-aminobutyric acid receptor A (GABA_A), and gamma-aminobutyric acid receptor B (GABA_B); 3) different brain structures are relevant to behaviors linked to GD, like: amygdala (including basolateral amygdala (BLA)), anterior cingulate cortex (ACC), hippocampus, infralimbic area, insular cortex (anterior and rostral agranular), nucleus accumbens (NAc), olfactory tubercle (island of Calleja), orbitofrontal cortex (OFC), medial prefrontal cortex (mPFC), prefrontal cortex (PFC) - subcortical network, striatum (ventral) and the subthalamic nucleus (STN); and 4) the search for GD treatments should consider this diversity of receptor/neurotransmitter systems and brain areas.

Successful management of automatic dysfunctional thoughts in the context of negative emotions

BACKGROUND AND OBJECTIVES

Cognitive and affective overloads trigger automatic dysfunctional thoughts and undermine their voluntary management [ADTs; Beck, A. T. (1976). Cognitive therapy and the emotional disorders. New York: Meridian; Wegner, D. M. (1994). Ironic processes of mental control. Psychology Review, 101(1), 34-52]. Taking into account intense negative emotions as triggers for the ADTs, we explored whether context (i.e., social context) and emotional experience (i.e., emotional intensity) predict the successful management of ADTs. We also examine the moderating role of difficulties in emotional regulation strategies.

METHOD

Thirty-eight participants wrote in a personal online diary of at least 10 times in 40 weeks. We analyzed the conditions for managing ADTs by means of multilevel in stages models.

RESULTS

Emotional intensity negatively predicted successful management of ADTs. Attempts to control ADTs and work context positively predicted successful management of ADTs. The negative relation between the emotional intensity and the management of ADTs was stronger as individuals were less aware of their own emotions, and was weaker as they had less clear representations of their own emotions. Superior access to emotion regulation strategies explained a stronger relationship between the work context and the successful management of ADTs.

CONCLUSIONS

We discuss theoretical and practical implications of the results.

The β-adrenoceptor blocker propranolol ameliorates compulsive-like gambling behaviour in a rodent slot machine task: implications for iatrogenic gambling disorder

Previous work has shown that chronic administration of the dopamine D_2/3 receptor agonist ropinirole invigorates performance on a rodent slot machine task (rSMT). This behavioural change appears superficially similar to the iatrogenic gambling disorder (GD) observed in a sub-set of patients with Parkinson's disease (PD), and has been associated with increased activation of the intra-cellular signalling proteins GSK3β and CREB in the striatum. Here, we wanted to determine whether this response to ropinirole could be attenuated by targeting these signalling proteins, and if the loss of dopaminergic innervation characteristic of PD would alter ropinirole's effects on the rSMT. Male Long Evans rats were trained on the rSMT. Dopaminergic terminals innervating the dorsolateral striatum were then lesioned bilaterally using the neurotoxin 6-hydroxydopamine hydrochloride (6-OHDA). Subsequently animals were implanted with osmotic mini-pumps delivering ropinirole. Lastly, animals were given dietary lithium (Li⁺ ), to inhibit the activation of GSK3β, or injections of the ß-adrenoceptor antagonist propranolol, which potently inhibits CREB as a secondary mechanism of action, and any changes in ropinirole-induced increases in compulsive-like engagement in the rSMT evaluated. Chronic ropinirole increased the number of trials animals completed, reproducing our original finding. This increase in task engagement was not altered in animals with 6-OHDA lesions, a putative model of early PD. In addition, the effects of ropinirole were not attenuated by administration of Li⁺ , but were ameliorated by propranolol. These data suggest that propranolol may represent a potential pharmacotherapy for the treatment of iatrogenic gambling.

Reinforcement learning models of risky choice and the promotion of risk-taking by losses disguised as wins in rats

Risky decisions are inherently characterized by the potential to receive gains or incur losses, and these outcomes have distinct effects on subsequent decision-making. One important factor is that individuals engage in loss-chasing, in which the reception of a loss is followed by relatively increased risk-taking. Unfortunately, the mechanisms of loss-chasing are poorly understood, despite the potential importance for understanding pathological choice behavior. The goal of the present experiment was to illuminate the mechanisms governing individual differences in loss-chasing and risky-choice behaviors. Rats chose between a low-uncertainty outcome that always delivered a variable amount of reward and a high-uncertainty outcome that probabilistically delivered reward. Loss-processing and loss-chasing were assessed in the context of losses disguised as wins (LDWs), which are loss outcomes that are presented along with gain-related stimuli. LDWs have been suggested to interfere with adaptive decision-making in humans and thus potentially increase loss-making. Here, the rats presented with LDWs were riskier, in that they made more choices for the high-uncertainty outcome. A series of nonlinear models were fit to individual rats' data to elucidate the possible psychological mechanisms that best account for individual differences in high-uncertainty choices and loss-chasing behaviors. The models suggested that the rats presented with LDWs were more prone to showing a stay bias following high-uncertainty outcomes compared to rats not presented with LDWs. These results collectively suggest that LDWs acquire conditioned reinforcement properties that encourage continued risk-taking and increase loss-chasing following previous high-risk decisions. (PsycINFO Database Record

Subthalamic Nucleus Deep Brain Stimulation: Basic Concepts and Novel Perspectives

Over the last decades, extensive basic and clinical knowledge has been acquired on the use of subthalamic nucleus (STN) deep brain stimulation (DBS) for Parkinson's disease (PD). It is now clear that mechanisms involved in the effects of this therapy are far more complex than previously anticipated. At frequencies commonly used in clinical practice, neural elements may be excited or inhibited and novel dynamic states of equilibrium are reached. Electrode contacts used for chronic DBS in PD are placed near the dorsal border of the nucleus, a highly cellular region. DBS may thus exert its effects by modulating these cells, hyperdirect projections from motor cortical areas, afferent and efferent fibers to the motor STN. Advancements in neuroimaging techniques may allow us to identify these structures optimizing surgical targeting. In this review, we provide an update on mechanisms and the neural elements modulated by STN DBS.

Deciphering Decision Making: Variation in Animal Models of Effort- and Uncertainty-Based Choice Reveals Distinct Neural Circuitries Underlying Core Cognitive Processes

Maladaptive decision-making is increasingly recognized to play a significant role in numerous psychiatric disorders, such that therapeutics capable of ameliorating core impairments in judgment may be beneficial in a range of patient populations. The field of "decision neuroscience" is therefore in its ascendancy, with researchers from diverse fields bringing their expertise to bear on this complex and fascinating problem. In addition to the advances in neuroimaging and computational neuroscience that contribute enormously to this area, an increase in the complexity and sophistication of behavioral paradigms designed for nonhuman laboratory animals has also had a significant impact on researchers' ability to test the causal nature of hypotheses pertaining to the neural circuitry underlying the choice process. Multiple such decision-making assays have been developed to investigate the neural and neurochemical bases of different types of cost/benefit decisions. However, what may seem like relatively trivial variation in behavioral methodologies can actually result in recruitment of distinct cognitive mechanisms, and alter the neurobiological processes that regulate choice. Here we focus on two areas of particular interest, namely, decisions that involve an assessment of uncertainty or effort, and compare some of the most prominent behavioral paradigms that have been used to investigate these processes in laboratory rodents. We illustrate how an appreciation of the diversity in the nature of these tasks can lead to important insights into the circumstances under which different neural regions make critical contributions to decision making.

Chronic administration of the dopamine D2/3 agonist ropinirole invigorates performance of a rodent slot machine task, potentially indicative of less distractible or compulsive-like gambling behaviour

RATIONALE

Whilst dopamine agonist therapies can successfully manage the symptoms of diseases such as Parkinson's disease (PD), fibromyalgia and restless leg syndrome, they can also cause impulse control and addiction disorders such as gambling disorder (GD). These compulsive behaviours seriously undermine the utility of such treatments.

OBJECTIVES

The objective of the study was to model this phenomenon using a rodent slot machine task (rSMT) in order to investigate the neurobiological basis underlying such behavioural changes.

METHODS

Male Long Evans rats were trained to perform the rSMT. The D₂-like agonist ropinirole, or saline, was then delivered continuously for 28 days via osmotic mini-pump. The effects of ropinirole on baseline rSMT performance, as well as extinction and reinstatement sessions, were determined during this time. Brain samples from key frontostriatal regions implicated in GD and PD were then harvested immediately or after a 4-week washout period during which behaviour returned to pre-drug baseline.

RESULTS

Ropinirole invigorated task performance, in that drug treatment resulted in a robust and sustained increase in the number of trials completed. Ex vivo analyses revealed that chronic ropinirole treatment led to a pattern of changes indicative of upregulation within the β-arrestin-AKT-GSK3β intracellular cascade, recently theorised to dominate D₂-mediated signalling under hyperdopaminergic conditions, in the dorsal striatum, rather than the canonical PKA-dependent signalling pathway associated with D₂ receptor activation.

CONCLUSIONS

Such findings provide novel insight into the role of dopamine signalling in mediating compulsive-like gambling behaviour and may inform more directed pharmacotherapies for the treatment of both idiopathic and iatrogenic GD.

Research Domain Criteria versus DSM V: How does this debate affect attempts to model corticostriatal dysfunction in animals?

For decades, the nosology of mental illness has been based largely upon the descriptions in the Diagnostic and Statistical Manual of the American Psychiatric Association (DSM). A recent challenge to the DSM approach to psychiatric nosology from the National Institute on Mental Health (USA) defines Research Domain Criteria (RDoC) as an alternative. For RDoC, psychiatric illnesses are not defined as discrete categories, but instead as specific behavioral dysfunctions irrespective of DSM diagnostic categories. This approach was driven by two primary weaknesses noted in the DSM: (1) the same symptoms occur in very different disease states; and (2) DSM criteria lack grounding in the underlying biological causes of mental illness. RDoC intends to ground psychiatric nosology in those underlying mechanisms. This review addresses the suitability of RDoC vs. DSM from the view of modeling mental illness in animals. A consideration of all types of psychiatric dysfunction is beyond the scope of this review, which will focus on models of conditions associated with frontostriatal dysfunction.

The agranular and granular insula differentially contribute to gambling-like behavior on a rat slot machine task: effects of inactivation and local infusion of a dopamine D4 agonist on reward expectancy

RATIONALE

Rats, like humans, are susceptible to the reinforcing effects of reward-related stimuli presented within a compound stimulus array, putatively analogous to the so-called near-miss effect. We have previously demonstrated using a rodent slot machine task (rSMT) that the reward expectancy these stimuli elicit is critically mediated by the dopamine D4 receptor. D4 receptors are principally located in prefrontal regions activated during slot machine play in humans, such as the insular cortex. The insula has recently attracted considerable interest as it appears to play a crucial role in substance and behavioral addictions. However, the insula is a heterogeneous area, and the relative contributions of subregions to addictive behaviors are unclear.

METHODS

Male Long Evans rats were trained to perform the rSMT, and then bilateral cannula targeting either the granular or agranular insula were implanted. The effects of inactivation and local administration of a D4 agonist were investigated.

RESULTS

Temporary inactivation of the agranular, but not the granular insula impaired performance on the rSMT. In contrast, local infusion of the D4 agonist PD168077 into the agranular insula had no effect on task performance, but when administered into the granular insula, it improved animals' ability to differentiate winning from non-winning trials. The agranular insula may therefore modulate decision making when conflicting stimuli are present, potentially due to its role in generating a cohesive emotional percept based on both externally and internally generated signals, whereas the granular insular is not critical for this process. Nevertheless, D4 receptors within the granular insula may amplify the incentive salience of aversive environmental stimuli.

DISCUSSION

These data provide insight into the neurobiological mechanism underpinning maladaptive reward expectancy during gambling and provide further evidence that D4 receptors represent a potential target for developing pharmacotherapies for problem gambling.

Chronic D2/3 agonist ropinirole treatment increases preference for uncertainty in rats regardless of baseline choice patterns

D_2/3 receptor agonists are effective treatments for Parkinson's disease (PD), but can precipitate impulse control disorders (ICDs) including gambling disorder (GD). The neurobiological mechanisms underlying this devastating side-effect of dopamine agonist replacement therapy (DRT), and any dependence on the dopamine depletion caused by PD, are unclear. It is also unclear whether previous biases towards risk or uncertainty are a risk factor for developing these ICDs. We investigated whether chronic D_2/3 agonist administration (5 mg/kg/day ropinirole for 28 days) altered performance of a rat model of gambling-like behaviour, the rodent betting task (rBT), and examined if baseline behaviour predicted this behavioural change. The rBT captures individual differences in subjective preference for uncertain outcomes: animals choose between guaranteed or probabilistic reinforcement of equal expected value. Chronic ropinirole dramatically increased selection of the uncertain option in two-thirds of animals, regardless of baseline preferences. The effect on choice in the rBT was replicated in a dorsolateral striatal 6-hydroxydopamine (6-OHDA) rat model of early PD. These studies are the first to look at individual differences in response to chronic, rather than pulsatile, dosing of DRT in a rodent model of gambling behaviour. These findings suggest that DRT-induced PG may stem from increases in subjective valuation of uncertainty. Such symptoms likely arise because of changes in dopaminergic striatal signalling caused by DRT rather than from an interaction between pre-morbid behaviours or PD itself.

Elucidating the role of D4 receptors in mediating attributions of salience to incentive stimuli on Pavlovian conditioned approach and conditioned reinforcement paradigms

The power of drug-associated cues to instigate drug 'wanting' and consequently promote drug seeking is a corner stone of contemporary theories of addiction. Gambling disorder has recently been added to the pantheon of addictive disorders due to the phenomenological similarities between the diseases. However, the neurobiological mechanism that may mediate increased sensitivity towards conditioned stimuli in addictive disorders is unclear. We have previously demonstrated using a rodent analogue of a simple slot machine that the dopamine D4 receptor is critically engaged in controlling animals' attribution of salience to stimuli associated with reward in this paradigm, and consequently may represent a target for the treatment of gambling disorder. Here, we investigated the role of acute administration of a D4 receptor agonist on animals' responsivity to conditioned stimuli on both a Pavlovian conditioned approach (autoshaping) and a conditioned reinforcement paradigm. Following training on one of the two tasks, separate cohorts of rats (male and female) were administered a dose of PD168077 shown to be maximally effective at precipitating errors in reward expectancy on the rat slot machine task (10mg/kg). However, augmenting the activity of the D4 receptors in this manner did not alter behaviour on either task. These data therefore provide novel evidence that the D4 receptor does not alter incentive motivation in response to cues on simple behavioural tasks.

Strain commonalities and differences in response-outcome decision making in mice

The ability to select between actions that are more vs. less likely to be reinforced is necessary for survival and navigation of a changing environment. A task termed "response-outcome contingency degradation" can be used in the laboratory to determine whether rodents behave according to such goal-directed response strategies. In one iteration of this task, rodents are trained to perform two food-reinforced behaviors, then the predictive relationship between one instrumental response and the associated outcome is modified by providing the reinforcer associated with that response non-contingently. During a subsequent probe test, animals can select between the two trained responses. Preferential engagement of the behavior most likely to be reinforced is considered goal-directed, while non-selective responding is considered a failure in response-outcome conditioning, or "habitual." This test has largely been used with rats, and less so with mice. Here we compiled data collected from several cohorts of mice tested in our lab between 2012 and 2015. Mice were bred on either a C57BL/6 or predominantly BALB/c strain background. We report that both strains of mice can use information acquired as a result of instrumental contingency degradation training to select amongst multiple response options the response most likely to be reinforced. Mice differ, however, during the training sessions when the familiar response-outcome contingency is being violated. BALB/c mice readily generate perseverative or habit-like response strategies when the only available response is unlikely to be reinforced, while C57BL/6 mice more readily inhibit responding. These findings provide evidence of strain differences in response strategies when an anticipated reinforcer is unlikely to be delivered.

A test of stress, cues, and re-exposure to large wins as potential reinstaters of suboptimal decision making in rats

The present experiment investigated potential reinstaters of suboptimal economic decision making in rats. Rats were first trained on a version of the rat Gambling Task under conditions designed to promote choice of a suboptimal option that occasionally resulted in large “wins” (four sucrose pellets). In a second phase, preference for this economically suboptimal option was reduced by substantially increasing the probability of punishment when this option was chosen. Then, three events were tested for their ability to reinstate choice of the suboptimal option. A brief period of re-exposure to a high frequency of large wins significantly increased choice of the suboptimal option. The pharmacological stressor yohimbine did not reinstate suboptimal choice, but did increase impulsive action as indexed by premature responding. Presentation of cues previously associated with large wins did not alter behavior. Results suggest reinstaters of suboptimal choice may differ from reinstaters of extinguished drug- and food-seeking behavior.

Prefrontal Cortical Inactivations Decrease Willingness to Expend Cognitive Effort on a Rodent Cost/Benefit Decision-Making Task

Personal success often necessitates expending greater effort for greater reward but, equally important, also requires judicious use of our limited cognitive resources (e.g., attention). Previous animal models have shown that the prelimbic (PL) and infralimbic (IL) regions of the prefrontal cortex (PFC) are not involved in (physical) effort-based choice, whereas human studies have demonstrated PFC contributions to (mental) effort. Here, we utilize the rat Cognitive Effort Task (rCET) to probe PFC's role in effort-based decision making. In the rCET, animals can choose either an easy trial, where the attentional demand is low but the reward (sugar) is small or a difficult trial on which both the attentional demand and reward are greater. Temporary inactivation of PL and IL decreased all animals' willingness to expend mental effort and increased animals' distractibility; PL inactivations more substantially affected performance (i.e., attention), whereas IL inactivations increased motor impulsivity. These data imply that the PFC contributes to attentional resources, and when these resources are diminished, animals shift their choice (via other brain regions) accordingly. Thus, one novel therapeutic approach to deficits in effort expenditure may be to focus on the resources that such decision making requires, rather than the decision-making process per se.

Skewed by Cues? The Motivational Role of Audiovisual Stimuli in Modelling Substance Use and Gambling Disorders

The similarity between gambling disorder (GD) and drug addiction has recently been recognized at the diagnostic level. Understanding the core cognitive processes involved in these addiction disorders, and in turn their neurobiological mechanisms, remains a research priority due to the enormous benefits such knowledge would have in enabling effective treatment design. Animal models can be highly informative in this regard. Although numerous rodent behavioural paradigms that capture different facets of gambling-like behaviour have recently been developed, the motivational power of cues in biasing individuals towards risky choice has so far received little attention despite the central role played by drug-paired cues in successful laboratory models of chemical dependency. Here, we review some of the comparatively simple paradigms in which reward-paired cues are known to modulate behaviour in rodents, such as sign-tracking, Pavlovian-to-instrumental transfer and conditioned reinforcement. Such processes are thought to play an important role in mediating responding for drug reward, and the need for future studies to address whether similar processes contribute to cue-driven risky choice is highlighted.

Translational Models of Gambling-Related Decision-Making

Gambling is a harmless, recreational pastime that is ubiquitous across cultures. However, for some, gambling becomes a maladaptive and compulsive, and this syndrome is conceptualized as a behavioural addiction. Laboratory models that capture the key cognitive processes involved in gambling behaviour, and that can be translated across species, have the potential to make an important contribution to both decision neuroscience and the study of addictive disorders. The Iowa gambling task has been widely used to assess human decision-making under uncertainty, and this paradigm can be successfully modelled in rodents. Similar neurobiological processes underpin choice behaviour in humans and rats, and thus, a preference for the disadvantageous "high-risk, high-reward" options may reflect meaningful vulnerability for mental health problems. However, the choice behaviour operationalized by these tasks does not necessarily approximate the vulnerability to gambling disorder (GD) per se. We consider a number of psychological challenges that apply to modelling gambling in a translational way, and evaluate the success of the existing models. Heterogeneity in the structure of gambling games, as well as in the motivations of individuals with GD, is highlighted. The potential issues with extrapolating too directly from established animal models of drug dependency are discussed, as are the inherent difficulties in validating animal models of GD in the absence of any approved treatments for GD. Further advances in modelling the cognitive biases endemic in human decision-making, which appear to be exacerbated in GD, may be a promising line of research.