Cued for risk: Evidence for an incentive sensitization framework to explain the interplay between stress and anxiety, substance abuse, and reward uncertainty in disordered gambling behavior

Propensity for risky choices despite lower cue reactivity in adolescent rats

Adolescence is a time of heightened risk-taking across species. Salient audiovisual cues associated with rewards are a common feature of gambling environments and have been connected to increased risky decision-making. We have previously shown that, in adult male rats, sign tracking - a behavioral measure of cue reactivity - predicts an individual's propensity for suboptimal risky choices in a rodent gambling task (rGT) with win-paired cues. However, adolescents perform less sign tracking than adult animals, suggesting that they are less cue-reactive than adults in some circumstances. Therefore, we investigated the performance of adolescent male rats on the rGT with win cues and examined its relationship with their sign-tracking behavior. We found that adolescents make more risky choices and fewer optimal choices on the rGT compared with adults, evidence of the validity of the rGT as a model of adolescent gambling behavior. We also confirmed that adolescents perform less sign tracking than adults, and we found that, unlike in adults, adolescents' sign tracking was unrelated to their risk-taking in the rGT. This implies that adolescent risk-taking is less likely than that of adults to be driven by reward-related cues. Finally, we found that adults trained on the rGT as adolescents retained an adolescent-like propensity toward risky choices, suggesting that early exposure to a gambling environment may have a long-lasting impact on risk-taking behavior.

Unpredictable, intermittent access to sucrose or water promotes increased reward pursuit in rats

Reward uncertainty can sensitize reward pathways, promoting increased reward-seeking and -taking behaviours. This is relevant to human conditions such as pathological gambling, eating disorders and drug addiction. In the context of addiction, preclinical self-administration procedures have been developed to model the intermittency of human drug use. These intermittent-access (IntA) procedures involve intermittent but predictable access to drug during self-administration sessions. However, human drug use typically involves intermittent and unpredictable drug access. We introduce a new procedure modeling unpredictable, intermittent access (UIntA) to a reinforcer, and we compare it to procedures that provide predictable reinforcer availability; continuous (ContA) or intermittent (IntA) access. Female rats self-administered water or liquid sucrose in daily hour-long sessions. IntA and ContA rats had access to a fixed volume of water or sucrose (0.1 ml), under a fixed ratio 3 schedule of reinforcement. IntA rats had predictable 5-min reinforcer ON and 25-min reinforcer OFF periods. ContA rats had 60 min of reinforcer access during each session. For UIntA rats, variation in the length of ON and OFF periods (1, 5 or 9 min/period), response requirement (variable ratio 3 schedule of reinforcement), reinforcer probability (50%) and quantity (0, 0.1 or 0.2 ml) introduced reward uncertainty. Following 14 daily self-administration sessions, UIntA rats showed the highest levels of responding for water or sucrose under progressive ratio conditions, responding under extinction conditions, and cue-induced reinstatement of sucrose seeking. Thus, unpredictable, intermittent reward access promotes increased reward pursuit. This has implications for modeling addiction and other disorders of increased reward seeking.

Large-Scale Web Scraping for Problem Gambling Research: A Case Study of COVID-19 Lockdown Effects in Germany

The COVID-19 pandemic and the measures to prevent its spread have had a negative impact on substance use behaviour. It is likely that social distancing and lockdown measures have also altered gambling behaviour, for instance shifting from land-based to online gambling. We used large-scale web scraping to analyse posting behaviour on a major German online gambling forum, gathering a database of more than 200k posts. We examined the usage of different subforums, i.e. terrestrial, online gambling and problem gambling sections, and changes in posting behaviour related to the casino closures that were part of the nationwide restrictions in Germany in 2020. There was a marked increase in newly registered users during the first lockdown compared to the preceding weeks, an increase in the number of posts in the online gambling subforum and concurrent decrease in the terrestrial gambling subforum. Further, the number of short-latency replies was higher during the first lockdown compared to the preceding weeks. Many users who posted in both the online and terrestrial forum contributed at least once to the problem gambling subforum, implying that the topic of problem gambling is widely discussed. Our findings may indicate a shift from terrestrial to online gambling during lockdown, and mirror the general increase in screen time and usage of online platforms after the onset of the COVID-19 pandemic. The analyses help to identify lockdown-related effects on gambling behaviour. These potentially detrimental effects pose a special threat for individuals at risk and may require monitoring and special public health measures.

Effects of predictive and incentive value manipulation on sign- and goal-tracking behavior

When a neutral stimulus is repeatedly paired with an appetitive reward, two different types of conditioned approach responses may develop: a sign-tracking response directed toward the neutral cue, or a goal-tracking response directed toward the location of impending reward delivery. Sign-tracking responses have been postulated to result from attribution of incentive value to conditioned cues, while goal-tracking reflects the assignment of only predictive value to the cue. We therefore hypothesized that sign-tracking rats would be more sensitive to manipulations of incentive value, while goal-tracking rats would be more responsive to changes in the predictive value of the cue. We tested sign- and goal-tracking before and after devaluation of a food reward using lithium chloride, and tested whether either response could be learned under negative contingency conditions that precluded any serendipitous reinforcement of the behavior that might support instrumental learning. We also tested the effects of blocking the predictive value of a cue using simultaneous presentation of a pre-conditioned cue. We found that sign-tracking was sensitive to outcome devaluation, while goal-tracking was not. We also confirmed that both responses are Pavlovian because they can be learned under negative contingency conditions. Goal-tracking was almost completely blocked by a pre-conditioned cue, while sign-tracking was much less sensitive to such interference. These results indicate that sign- and goal-tracking may follow different rules of reinforcement learning and suggest a need to revise current models of associative learning to account for these differences.

Understanding gambling in the United Kingdom: A qualitative study on the experiences of gamblers' families

This study focuses on understanding the experiences of family members of problem gamblers in the United Kingdom and the gambling consequences in their lives. Family members of problem gamblers, even though they suffer from gambling consequences, the impacts of gambling are under-researched. Qualitative research through in-depth interviews was employed. Thematic analysis was used to gain a deeper insight into gambling. Nine female participants were interviewed based on a semi-structured questionnaire. The results of this study indicated that close family members of problem gamblers had suffered not only financial devastation but also harsh psychological and mental health damages. Furthermore, family members suffer from gamblers' abusive and violent behaviors. Addiction was a key factor of gamblers' habit; fear, anxiety, and depression were some of the health issues derived from gambling. Overall, gambling addiction leads to further addiction, crime, and severe, family-relation sufferings. The study results suggest that the London Gambling Commission and regulating authority should change gambling policy, reduce gambling points, and limit gambling slot machines in food markets and community areas. More support is needed for family members affected by gamblers' addictive gambling behaviors.

The Impact of Social Media Salience on the Subjective Value of Social Cues

Like face-to-face interactions, evidence shows that interacting on social media is rewarding. However, the rewards associated with social media are subject to unpredictable delays, which may shape how they are experienced. Specifically, these delays might enhance the subjective desirability of social rewards and subsequent reward-seeking behavior by sensitizing people to the presence of such rewards. Here, we ask whether thinking about a recent social media post or conversation influences the subjective value of monetary and social rewards. Across two studies, we find that individuals who are thinking about a recent social media post are more likely to sacrifice small financial gains for the chance to see a genuine smile (a social reward) compared with those who are thinking about a recent conversation. This suggests that rather than satisfying social needs, thinking about social media interactions enhances the subjective value of social rewards, potentially explaining the incentive value of social media.

The Role of Impulsivity and Reward Deficiency in "Liking" and "Wanting" of Potentially Problematic Behaviors and Substance Uses

A few studies have examined the changes in substance- and behavior-related "wanting" and "liking" of human subjects, the key properties of Incentive Sensitization Theory (IST). The aim of this study was to examine the dissociation between "wanting" and "liking" as a function of usage frequency, intensity, and subjective severity in individuals across four substances (alcohol, nicotine, cannabis, and other drugs) and ten behaviors (gambling, overeating, gaming, pornography use, sex, social media use, Internet use, TV-series watching, shopping, and work). Also, the potential roles of impulsivity and reward deficiency were investigated in "wanting," "liking," and wellbeing. The sex differences between "wanting" and "liking" were also examined. Based on our findings using structural equation modeling with 749 participants (503 women, M age = 35.7 years, SD = 11.84), who completed self-report questionnaires, "wanting" increased with the severity, frequency, and intensity of potentially problematic use, while "liking" did not change. Impulsivity positively predicted "wanting," and "wanting" positively predicted problem uses/behaviors. Reward deficiency positively predicted problem uses/behaviors, and both impulsivity and problem uses/behaviors negatively predicted wellbeing. Finally, women showed higher levels of "wanting," compared to men. These findings demonstrate the potential roles of incentive sensitization in both potentially problematic substance uses and behaviors.

Value-based cognition and drug dependency

Value-based decision-making is thought to play an important role in drug dependency. Achieving elevated levels of euphoria or ameliorating dysphoria/pain may motivate goal-directed drug consumption in both drug-naïve and long-time users. In other words, drugs become viewed as the preferred means of attaining a desired internal state. The bias towards choosing drugs may affect one's cognition. Observed biases in learning, attention and memory systems within the brain gradually focus one's cognitive functions towards drugs and related cues to the exclusion of other stimuli. In this narrative review, the effects of drug use on learning, attention and memory are discussed with a particular focus on changes across brain-wide functional networks and the subsequent impact on behaviour. These cognitive changes are then incorporated into the cycle of addiction, an established model outlining the transition from casual drug use to chronic dependency. If drug use results in the elevated salience of drugs and their cues, the studies highlighted in this review strongly suggest that this salience biases cognitive systems towards the motivated pursuit of addictive drugs. This bias is observed throughout the cycle of addiction, possibly contributing to the persistent hold that addictive drugs have over the dependent. Taken together, the excessive valuation of drugs as the preferred means of achieving a desired internal state affects more than just decision-making, but also learning, attentional and mnemonic systems. This eventually narrows the focus of one's thoughts towards the pursuit and consumption of addictive drugs.

Anxiety and emotional-behavioral problems of adolescents in China: evidence for a serial mediation model of alexithymia and dependency

High prevalence of emotional and behavioral problems among Chinese adolescence has been reported. This study seeks to investigate the mediating effect of alexithymia and dependency on anxiety and emotional-behavioral problems among adolescents. The study population included 519 adolescents. The assessments included the completion of standardized scales such as the Multidimensional Anxiety Scale (MASC), the Toronto Alexithymia Scale (TAS-20), the Depressive Experiences Questionnaire (DEQ), the Strengths and Difficulties Questionnaire (SDQ). Independent-sample t-tests, bivariate correlation, and serial mediation analyses were performed using SPSS23.0. Bivariate analyses revealed that anxiety, emotional-behavioral problem, alexithymia, and dependency were positively correlated. Alexithymia and dependency play a significant role in mediating the effect of multidimensional anxiety on emotional-behavioral problems. The effects of the two mediating paths were 69.86% and 7.81% for indirect effect through alexithymia, dependency, and specific indirect effect by alexithymia and dependency was 12.33%. Anxiety and emotional-behavioral problems mediate the relationship between alexithymia and dependency.

Psychiatric Drug Prescription and Temporal Associations with a First Diagnosis of Gambling Disorder—Results from a National Register Study

Psychiatric comorbidity is common in gambling disorder (GD), but there are few studies on larger nationwide samples of treatment-seeking patients. Also, temporal associations between GD and other psychiatric disorders are often difficult to study. To address the prevalence and the temporal associations of prescriptions for psychiatric disorders — both in specialized care and primary care — in patients with a GD diagnosis (ICD-10 F63.0). Data was derived from national health registers in Sweden. All patients who were diagnosed with GD in specialized health care in 2005–2016 were included and run against the nationwide database on prescription of pharmaceuticals aimed for psychiatric disorders (n = 2018). Prevalence of psychiatric drug prescription was used as a proxy for psychiatric comorbidity and studied for two 2-year periods (period 1 and 2) prior to GD and one 2-year period (period 3) after the diagnosis. Controlling for gender, age, and time periods, for eight drug categories (anti- epileptics, anti-psychotics, benzodiazepine derivatives, anxiolytics, hypnotics, anti- depressants and drugs used in addictive disorders), significant increases in drug prescription were seen. For central stimulants, a significant increase was seen upon receiving the GD diagnosis (from period 2 to 3), and for benzodiazepines, an increase was seen prior to the GD diagnosis (from period 1 to 2), but not upon diagnosis (from period 2 to 3). Psychiatric comorbidity in GD is common. Drug prescription for psychiatric problems increased markedly in the years temporarily associated with a first diagnosis of GD. The findings may call for early screening for problem gambling in patients with treatment contacts for increasingly poor mental health.

Aberrant orbitofrontal cortex reactivity to erotic cues in Compulsive Sexual Behavior Disorder

BACKGROUND AND AIMS

Compulsive Sexual Behavior Disorder (CSBD) is characterized by increased reactivity to erotic reward cues. Cue-encoded reward parameters, such as type (e.g. erotic or monetary) or probability of anticipated reward, shape reward-related motivational processes, increase the attractiveness of cues and therefore might enhance maladaptive behavioral patterns in CSBD. Studies on the neural patterns of cue processing in individuals with CSBD have been limited mainly to ventral striatal responses. Therefore, here we aimed to examine the cue reactivity of multiple key structures in the brain's reward system, taking into account not only the type of predicted reward but also its probability.

METHODS

Twenty Nine men seeking professional help due to CSBD and 24 healthy volunteers took part in an fMRI study with a modified Incentive Delay Task with erotic and monetary rewards preceded by cues indicating a 25%, 50%, or 75% chance of reward. Analyses of functional patterns of activity related to cue type and probability were conducted on the whole-brain and ROI levels.

RESULTS

Increased anticipatory response to cues predictive of erotic rewards was observed among CSBD participants when compared to controls, in the ventral striatum and anterior orbitofrontal cortex (aOFC). The activity in aOFC was modulated by reward probability.

DISCUSSION AND CONCLUSIONS

Type of anticipated reward (erotic vs monetary) affects reward-related behavioral motivation in CSBD more strongly than reward probability. We present evidence of abnormal aOFC function in CSBD by demonstrating the recruitment of additional subsections of this region by erotic reward cues.

Noradrenergic contributions to cue-driven risk-taking and impulsivity

RATIONALE

The flashing lights and sounds of modern casinos are alluring and may contribute to the addictive nature of gambling. Such cues can have a profound impact on the noradrenaline (NA) system, which could therefore be a viable therapeutic target for gambling disorder (GD). While there is substantial evidence to support the involvement of NA in the impulsive symptoms of GD, its function in mediating the "pro-addictive" impact of cues is less understood.

OBJECTIVE

We wished to investigate the role of NA in our rodent assay of decision making and impulsivity, the cued rat gambling task (crGT). Given that sex differences are prominent in addiction disorders, and increasingly reported in the monoaminergic regulation of behaviour, we also prioritised evaluating noradrenergic drugs in both sexes.

METHODS

Female and male rats were trained to stability on the crGT and then given intraperitoneal injections of the noradrenaline reuptake inhibitor atomoxetine, the α_2A receptor agonist guanfacine, the beta receptor antagonist propranolol, and the α₂ receptor antagonist yohimbine.

RESULTS

Atomoxetine dose-dependently improved decision-making score. Guanfacine selectively enhanced decision making in risk-preferring males and optimal performing females. Propranolol and yohimbine did not influence decision making. Atomoxetine and guanfacine reduced premature responses, while yohimbine bi-phasically affected this index of motor impulsivity.

CONCLUSIONS

These results support the hypothesis that NA is an important neuromodulator of the cue-induced deficits in decision making observed in laboratory-based gambling paradigms, and suggest that NAergic drugs like atomoxetine and guanfacine may be useful in treating GD.

Valuation system connectivity is correlated with poly-drug use in young adults

Poly-drug consumption contributes to fatal overdose in more than half of all poly-drug users. Analyzing decision-making networks may give insight into the motivations behind poly-drug use. We correlated average functional connectivity of the valuation system (VS), executive control system (ECS) and valuation-control complex (VCC) in a large population sample (n = 992) with drug use behaviour. VS connectivity is correlated with sedative use, ECS connectivity is separately correlated with hallucinogens and opiates. Network connectivity is also correlated with drug use via two-way interactions with other substances including alcohol and tobacco. These preliminary findings can contribute to our understanding of the common combinations of substance co-use and associated neural patterns.

Value, drug addiction and the brain

Over the years, various models have been proposed to explain the psychology and biology of drug addiction, built primarily around the habit and compulsion models. Recent research indicates drug addiction may be goal-directed, motivated by excessive valuation of drugs. Drug consumption may initially occur for the sake of pleasure but may transition to a means of escaping withdrawal, stress and negative emotions. In this hypothetical paper, we propose a value-based neurobiological model for drug addiction. We posit that during dependency, the value-based decision-making system in the brain is not inactive but has instead prioritized drugs as the reward of choice. In support of this model, we consider the role of valuation in choice, its influence on pleasure and punishment, and how valuation is contrasted in impulsive and compulsive behaviours. We then discuss the neurobiology of value, beginning with the dopaminergic system and its relationship with incentive salience before moving to brain-wide networks involved in valuation, control and prospection. These value-based neurobiological components are then integrated into the cycle of addiction as we consider the development of drug dependency from a valuation perspective. We conclude with a discussion of cognitive interventions utilizing value-based decision-making, highlighting not just advances in recalibrating the valuation system to focus on non-drug rewards, but also areas for improvement in refining this approach.

Incentive sensitization in binge behaviors: A mini review on electrophysiological evidence

Introduction

Binge behavior not only refers to the consumption of substances such as alcohol or food, but is also used in relation to gaming, watching and gambling. Dependent on context it makes for a widespread, benign recreational activity or can pose a serious mental health problem with deleterious consequences. Incentive sensitization theory describes the attribution of salience towards stimuli strongly associated with dopamine-mediated reward as a result of repeated consumption. The sensitized neural networks cause cue-triggered craving and excessive desire, but thus, this mechanism may also be applicable to stimulus-induced behaviors not associated with classical withdrawal symptoms. Event-related potentials (ERP) are a useful method of examining motivated attention towards incentive stimuli. This mini review aims to synthesize ERP findings from different types of binge behaviors in order to compare cue-reactivity to incentive stimuli.

Methods

Studies investigating binge drinking, binge eating as well as binge watching, gaming and gambling were screened. To limit the influence of concurrent task demands, ERP studies applying picture viewing paradigms with incentive stimuli were selected.

Results

Across binge behaviors, evidence on altered mid-latency ERPs has been mixed. However, studies investigating later stages of attentional processes more consistently find enlarged P300 and late positive potentials (LPP) amplitudes to relevant cues.

Conclusion

An altered attentional processing of incentive stimuli reflecting motivated attention is in line with incentive sensitization theory. Considering the limited number of studies, especially regarding binge behaviors not involving substances, more research is needed to attain a more thorough understanding of incentive sensitization across binge behaviors.

Positive Affect: Nature and brain bases of liking and wanting

The positive affect of rewards is an important contributor to well-being. Reward involves components of pleasure 'liking', motivation 'wanting', and learning. 'Liking' refers to the hedonic impact of positive events, with underlying mechanisms that include hedonic hotspots in limbic brain structures that amplify 'liking' reactions. 'Wanting' refers to incentive salience, a motivational process that makes reward cues attractive and able to trigger craving for their reward, mediated by larger dopamine-related mesocorticolimbic networks. Under normal conditions, 'liking' and 'wanting' cohere. However, 'liking' and 'wanting' can be dissociated by alterations in neural signaling, either induced in animal neuroscience laboratories or arising spontaneously in addictions and other affective disorders, which can be detrimental to positive well-being.

A proposed role for glucocorticoids in mediating dopamine-dependent cue-reward learning

Learning to respond appropriately to one's surrounding environment is fundamental to survival. Importantly, however, individuals vary in how they respond to cues in the environment and this variation may be a key determinant of psychopathology. The ability of seemingly neutral cues to promote maladaptive behavior is a hallmark of several psychiatric disorders including, substance use disorder, post-traumatic stress disorder, eating disorders and obsessive-compulsive disorder. Thus, it is important to uncover the neural mechanisms by which such cues are able to attain inordinate control and promote psychopathological behavior. Here, we suggest that glucocorticoids play a critical role in this process. Glucocorticoids are primarily recognized as the main hormone secreted in response to stress but are known to exert their effects across the body and the brain, and to affect learning and memory, cognition and reward-related behaviors, among other things. Here we speculate that glucocorticoids act to facilitate a dopamine-dependent form of cue-reward learning that appears to be relevant to a number of psychiatric conditions. Specifically, we propose to utilize the sign-tracker/goal-tracker animal model as a means to capture individual variation in stimulus-reward learning and to isolate the role of glucocorticoid-dopamine interactions in mediating these individual differences. It is hoped that this framework will lead to the discovery of novel mechanisms that contribute to complex neuropsychiatric disorders and their comorbidity.

The lateral hypothalamus and orexinergic transmission in the paraventricular thalamus promote the attribution of incentive salience to reward-associated cues

RATIONALE

Prior research suggests that the neural pathway from the lateral hypothalamic area (LHA) to the paraventricular nucleus of the thalamus (PVT) mediates the attribution of incentive salience to Pavlovian reward cues. However, a causal role for the LHA and the neurotransmitters involved have not been demonstrated in this regard.

OBJECTIVES

To examine (1) the role of LHA in the acquisition of Pavlovian conditioned approach (PavCA) behaviors, and (2) the role of PVT orexin 1 receptors (OX1r) and orexin 2 receptors (OX2r) in the expression of PavCA behaviors and conditioned reinforcement.

METHODS

Rats received excitotoxic lesions of the LHA prior to Pavlovian training. A separate cohort of rats characterized as sign-trackers (STs) or goal-trackers (GTs) received the OX1r antagonist SB-334867, or the OX2r antagonist TCS-OX2-29, into the PVT, to assess their effects on the expression of PavCA behavior and on the conditioned reinforcing properties of a Pavlovian reward cue.

RESULTS

LHA lesions attenuated the development of sign-tracking behavior. Administration of either the OX1r or OX2r antagonist into the PVT reduced sign-tracking behavior in STs. Further, OX2r antagonism reduced the conditioned reinforcing properties of a Pavlovian reward cue in STs.

CONCLUSIONS

The LHA is necessary for the development of sign-tracking behavior; and blockade of orexin signaling in the PVT attenuates the expression of sign-tracking behavior and the conditioned reinforcing properties of a Pavlovian reward cue. Together, these data suggest that LHA orexin inputs to the PVT are a key component of the circuitry that encodes the incentive motivational value of reward cues.

Translating concepts of risk and loss in rodent models of gambling and the limitations for clinical applications

Gambling involves placing something of value at risk in exchange for the opportunity to potentially gain something of greater value in return. A variety of gambling paradigms have been designed to study the maladaptive decision-making that underlies problematic gambling. Central to these gambling models are the definitions of "risk" and "loss", especially when translating the results from rodent studies to clinical applications. Risk and loss are not mutually exclusive but rather share some overlap. With careful interpretation and consideration of the limitations of these behavioral paradigms, results from rodent models may provide insights into the neurobiology of risky decision-making that leads to problematic gambling in humans.

From sign-tracking to attentional bias: Implications for gambling and substance use disorders

Sign-tracking behavior in Pavlovian autoshaping is known to be a relevant index of the incentive salience attributed to reward-related cues. Evidence has accumulated to suggest that animals that exhibit a sign-tracker phenotype are especially vulnerable to addiction and relapse due to their proneness to attribute incentive salience to drug cues, and their relatively weak cognitive and attentional control over their behavior. Interestingly, sign-tracking is also influenced by reward uncertainty in a way that may promote gambling disorder. Research indicates that reward uncertainty sensitizes sign-tracking responses and favors the development of a sign-tracker phenotype, compatible with the conditioned attractiveness of lights and sounds in casinos for problem gamblers. The study of attentional biases in humans (an effect akin to sign-tracking in animals) leads to similar observations, notably that the propensity to develop attraction for conditioned stimuli (CSs) is predictive of addictive behavior. Here we review the literature on drug addiction and gambling disorder, highlighting the similarities between studies of sign-tracking and attentional biases.

Reward uncertainty attributes incentive value to reward proximal cues, while amphetamine sensitization reverts attention to more predictive reward distal cues

Slot-machine gambling incorporates numerous audiovisual cues prior to and during reward delivery (e.g. spinning wheels, flashing lights, celebratory sounds). Over time, these cues may motivate playing and even elicit cravings and relapse in those affected by gambling disorder. Animal studies suggest a heightened attraction to these cues despite diminished predictive ability under reward uncertainty, as evidenced by sign-tracking behavior in rats. Repeated amphetamine administration may also enhance the incentive value attributed to cues. Here, we explored the impact of reward uncertainty and prior amphetamine sensitization on the relative attractiveness and conditioned reinforcing properties of serial Pavlovian cues with different degrees of predictive and incentive value in rats. Animals were sensitized through repeated injections of amphetamine (1-4 mg/kg) or saline and then trained in a Pavlovian autoshaping task involving two sequential lever-auditory cue combinations (CS1, CS2) under Certain (100%-1) or Uncertain (50%-1-2-3) reward conditions. Subsequently, we evaluated the impact of acute amphetamine exposure on cue attraction. Our results suggest that Uncertainty alone enhanced attraction towards the reward-proximal CS2. However, combined sensitization and Uncertainty reversed cue preference relative to Uncertainty alone, enhancing attraction towards the more predictive reward-distal CS1. Both cues acquired conditioned reinforcing properties, despite the CS2 being otherwise ignored in all groups besides Uncertainty. However, combined sensitization and Uncertainty increased the reinforcing value of both cues and doubled the amount of interaction with the CS1 lever per presentation. Our results imply competitive mechanisms for attributing incentive value to gambling-related cues between reward uncertainty, prior amphetamine sensitization, and acute amphetamine administration.

Temporal Structure of Mixed States: Does Sensitization Link Life Course to Episodes?

Susceptibility to combined depressive and manic syndromes correlates strongly with arousal-related symptoms including impulsivity, anxiety and agitation. This relationship to a driven, "mixed" activation-depression state, generated by a life-long process, was described in classical times. Course of illness in mixed states includes increased episode frequency, duration, earlier onset, and association with addiction- and trauma/stress-related disorders. Mixed episodes have catecholamine and hypothalamic-pituitary-adrenocortical activity increased beyond nonmixed states of similar symptom severity. These properties resemble behavioral sensitization, where salient, survival-related stimuli (traumatic or rewarding) can generate persistently exaggerated responses with disrupted arousal and reward, with potential for suicide and other severe consequences.

Using rodent models to understand interactions between gambling and substance use

Substance use is strongly associated with gambling, but the nature of this association can be difficult to determine. Rodents offer the opportunity to test causal models of these relationships through isolation of individual variables of interest. This review describes recent research in rodents showing: a) predisposing factors for both gambling-like behavior and substance use; b) exposure to drugs of abuse increasing gambling-like behavior; c) experience with gambling-like behavior increasing substance use; and d) links between gambling-like behavior and substance use in models of Parkinson's disease therapies. These findings reveal novel relationships between gambling and substance use, and highlight the utility of rodent models for future work in this area.

Examining neural reactivity to gambling cues in the age of online betting

Purpose of Review

The goal of this review is to provide new insights as to how and why functional magnetic resonance imaging (fMRI) research on gambling cue reactivity can contribute to significant progress towards the understanding of gambling disorder. After having offered a detailed description of experimental paradigms and a comprehensive summary of findings related to gambling cue reactivity, the present review suggests methodological avenues for future research.

Recent Findings

The fMRI literature on problem gambling has identified the main neural pathways associated with reactivity to gambling cues. Yet, the current knowledge on the key factors underlying cue reactivity in gambling is still very incomplete. Here, we suggest that the recent expansion of online sports betting calls for a new line of research offering a fine-grained and up-to-date approach of neural cue reactivity in gambling disorder.

Summary

Experimental designs that investigate individual-specific and study-specific factors related to sports betting have the potential to foster progress towards efficient treatment and prevention of gambling disorder.

Prior Exposure to Salient Win-Paired Cues in a Rat Gambling Task Increases Sensitivity to Cocaine Self-Administration and Suppresses Dopamine Efflux in Nucleus Accumbens: Support for the Reward Deficiency Hypothesis of Addiction

Rats trained to perform a version of the rat gambling task (rGT) in which salient audiovisual cues accompany reward delivery, similar to commercial gambling products, show greater preference for risky options. Given previous demonstrations that probabilistic reinforcement schedules can enhance psychostimulant-induced increases in accumbal DA and locomotor activity, we theorized that performing this cued task could perpetuate a proaddiction phenotype. Significantly more rats developed a preference for the risky options in the cued versus uncued rGT at baseline, and this bias was further exacerbated by cocaine self-administration, whereas the choice pattern of optimal decision-makers was unaffected. The addition of reward-paired cues therefore increased the proportion of rats exhibiting a maladaptive cognitive response to cocaine self-administration. Risky choice was not associated with responding for conditioned reinforcement or a marker of goal/sign-tracking, suggesting that reward-concurrent cues precipitate maladaptive choice via a unique mechanism unrelated to simple approach toward, or responding for, conditioned stimuli. Although "protected" from any resulting decision-making impairment, optimal decision-makers trained on the cued rGT nevertheless self-administered more cocaine than those trained on the uncued task. Collectively, these data suggest that repeated engagement with heavily cued probabilistic reward schedules can drive addiction vulnerability through multiple behavioral mechanisms. Rats trained on the cued rGT also exhibited blunted locomotor sensitization and lower basal accumbal DA levels, yet greater cocaine-induced increases in accumbal DA efflux. Gambling in the presence of salient cues may therefore result in an adaptive downregulation of the mesolimbic DA system, rendering individuals more sensitive to the deleterious effects of taking cocaine.SIGNIFICANCE STATEMENT Impaired cost/benefit decision making, exemplified by preference for the risky, disadvantageous options on the Iowa Gambling Task, is associated with greater risk of relapse and treatment failure in substance use disorder. Understanding factors that enhance preference for risk may help elucidate the neurobiological mechanisms underlying maladaptive decision making in addiction, thereby improving treatment outcomes. Problem gambling is also highly comorbid with substance use disorder, and many commercial gambling products incorporate salient win-paired cues. Here we show that adding reward-concurrent cues to a rat analog of the IGT precipitates a hypodopaminergic state, characterized by blunted accumbal DA efflux and attenuated locomotor sensitization, which may contribute to the enhanced responsivity to uncertain rewards or the reinforcing effects of cocaine we observed.