Incentive-elicited striatal activation in adolescent children of alcoholics

Fractionating impulsivity and reward-related phenotypes in adolescent mice

Adolescence is a developmental period characterized by changes in the brain and behavior, including heightened reward seeking, increased impulsivity, and elevated risk-taking behavior. It is also a sensitive period for the development of a number of behavioral and psychiatric disorders associated with pathological phenotypes of reward processing and impulsivity. Landmark human studies are charting the development of impulsivity and other reward-related phenotypes to identify the facets and timecourse of the adolescent phenotype. Collecting similar data from mice is important to enable molecular, cellular, and circuit-level interrogation of adolescent maturation of reward, motivation, and impulsive behavior. These complex phenotypes have traditionally been difficult to assay in adolescent mice. Here, using a combination of approaches including homecage testing, we tested a number of facets of reward seeking, impulsivity, motivation, and incentive salience attribution during adolescent development. We found that adolescent mice show increased reward seeking, impulsive action, and motivation. Interestingly, we found no effect of adolescence on impulsive choice, sign-tracking, reward-learning, or conditioned reinforcement. Overall, our studies set the stage for approaches to study multi-faceted phenotypes related to impulsivity and other reward-related behaviors in adolescent mice to examine the developmental trajectories of brain and behavior.

How adverse childhood experiences get under the skin: A systematic review, integration and methodological discussion on threat and reward learning mechanisms

Adverse childhood experiences (ACEs) are a major risk factor for the development of multiple psychopathological conditions, but the mechanisms underlying this link are poorly understood. Associative learning encompasses key mechanisms through which individuals learn to link important environmental inputs to emotional and behavioral responses. ACEs may impact the normative maturation of associative learning processes, resulting in their enduring maladaptive expression manifesting in psychopathology. In this review, we lay out a systematic and methodological overview and integration of the available evidence of the proposed association between ACEs and threat and reward learning processes. We summarize results from a systematic literature search (following PRISMA guidelines) which yielded a total of 81 articles (threat: n=38, reward: n=43). Across the threat and reward learning fields, behaviorally, we observed a converging pattern of aberrant learning in individuals with a history of ACEs, independent of other sample characteristics, specific ACE types, and outcome measures. Specifically, blunted threat learning was reflected in reduced discrimination between threat and safety cues, primarily driven by diminished responding to conditioned threat cues. Furthermore, attenuated reward learning manifested in reduced accuracy and learning rate in tasks involving acquisition of reward contingencies. Importantly, this pattern emerged despite substantial heterogeneity in ACE assessment and operationalization across both fields. We conclude that blunted threat and reward learning may represent a mechanistic route by which ACEs may become physiologically and neurobiologically embedded and ultimately confer greater risk for psychopathology. In closing, we discuss potentially fruitful future directions for the research field, including methodological and ACE assessment considerations.

Caffeinated Soda Intake in Children Is Associated with Neurobehavioral Risk Factors for Substance Misuse

BACKGROUND AND OBJECTIVES

Use of psychotropic substances in childhood has been associated with both impulsivity and other manifestations of poor executive function as well as escalation over time to use of progressively stronger substances. However, how this relationship may start in earlier childhood has not been well explored. Here, we investigated the neurobehavioral correlates of daily caffeinated soda consumption in preadolescent children and examined whether caffeinated soda intake is associated with a higher risk of subsequent alcohol initiation.

METHODS

Using Adolescent Brain Cognitive Development study data (N = 2,092), we first investigated cross-sectional relationships between frequent caffeinated soda intake and well-known risk factors of substance misuse: impaired working memory, high impulsivity, and aberrant reward processing. We then examined whether caffeinated soda intake at baseline predicts more alcohol sipping at 12 months follow-up using a machine learning algorithm.

RESULTS

Daily consumption of caffeinated soda was cross-sectionally associated with neurobehavioral risk factors for substance misuse such as higher impulsivity scores and lower working memory performance. Furthermore, caffeinated soda intake predicted a 2.04 times greater likelihood of alcohol sipping after 12 months, even after controlling for rates of baseline alcohol sipping rates.

CONCLUSIONS

These findings suggest that previous linkages between caffeine and substance use in adolescence also extend to younger initiation, and may stem from core neurocognitive features thought conducive to substance initiation.

Brain response in heavy drinkers during cross-commodity alcohol and money discounting with potentially real rewards: A preliminary study

Background

Alcohol use disorder (AUD) is associated with exaggerated preference for immediate rewards, a candidate endophenotype for use disorders. Addiction symptomology is often well-described by the preference for immediate intoxication over other delayed prosocial rewards. We measured brain activation in AUD-implicated regions during a cross-commodity delay discounting (CCD) task with choices for immediate alcohol and delayed money.

Methods

Heavy drinkers (n=24) experienced a brief intravenous alcohol infusion prime, regained sobriety, then chose between 'One Shot' and delayed money in an adjusting delay CCD task (sober and intoxicated); also during fMRI (sober). Participants also performed a behavioral sensation seeking task and completed self-report inventories of other risk factors. We assessed brain activation to choices representing immediate intoxication versus delayed money rewards in a priori regions of interest defined within the framework of Addictions NeuroImaging Assessment.

Results

Activation to CCD choice versus control trials activated paralimbic and ventral frontal cortical regions, including orbital and medial prefrontal cortex, posterior cingulate/retrosplenial cortex, angular and superior frontal gyri. We detected no differences between immediate or delayed choices. Left medial orbitofrontal cortex activation correlated with alcohol-induced wanting for alcohol; females showed greater activation than males. Behavioral sensation seeking correlated with right nucleus accumbens task engagement.

Conclusions

Alcohol decision-making elicited activation in regions governing reward, introspection, and executive decision-making in heavy drinkers, demonstrating the utility of laboratory tasks designed to better model real-world choice. Our findings suggest that the brain processes subserving immediate and delayed choices are mostly overlapping, even with varied commodities.

The impact of sensation seeking personality trait on acute alcohol-induced disinhibition

BACKGROUND

Acute alcohol-related behavioral disinhibition has been well studied. But whether individual differences in the personality trait sensation seeking affect alcohol-induced behavioral disinhibition remains uncertain.

METHODS

The present study used functional near-infrared spectroscopy (fNIRS) technique and a response inhibition task (i.e., Go/No-Go) to determine the impact of the sensation seeking trait on the relationship between acute alcohol administration and inhibitory control capacity, and further investigate the neural mechanisms underlying this behavioral effect. Twenty-five high-sensation seekers and twenty-six low-sensation seekers were enrolled in this study. These participants attended two sessions: once for alcohol intake (0.5g/kg) and once for placebo intake (0g/kg).

RESULTS

Our results showed that high-sensation seekers relative to low-sensation seekers showed a significant decrease in inhibition accuracy under alcohol versus the placebo condition. Moreover, reduced prefrontal activity following acute alcohol consumption was more pronounced in high-sensation seekers compared with low-sensation seekers.

CONCLUSIONS

These findings showed that alcohol-induced behavioral disinhibition was affected by the personality trait sensation seeking and that recruitment of the prefrontal cortex contributed to the observed behavioral effect.

NEURAL RESPONSE TO THREAT AND REWARD AMONG YOUNG ADULTS AT RISK FOR ALCOHOL USE DISORDER

Alcohol use disorder is 50% heritable; those with positive family histories represent an at-risk group within which we can test anticipation of threat and reward prior to development of harmful alcohol use. We examined neural correlates of the interaction between family history, threat anticipation (unpredictable threat), and monetary reward anticipation, in a sample of healthy young adults with (n=31) and without (n=44) family histories of harmful alcohol use. We used a modified Monetary Incentive Delay task with sustained threat of hearing a scream during fMRI. We examined the interaction between family history group, anticipation of threat, and anticipation of reward in the insula, nucleus accumbens, and medial prefrontal cortex. Family history positive individuals showed less activation in the left insula during both safe and threat blocks compared to family history negative individuals (p=0.005), but the groups did not differ as a function of unpredictable threat (p>0.70). We found an interaction (p=0.048) between cue and group in the right nucleus accumbens where the family history positive group showed less differentiation to the anticipation of gaining $5 and losing $5 relative to gaining $0. The family history positive group also reported less excitement for trials to gain $5 relative to gaining $0 (p<0.001). Prior to chronic heavy alcohol use, individuals with, relative to without, enriched risk may have diminished reward processing via both neural and behavioral markers to potential rewarding and negative consequences. Neural response to unpredictable threat may not be a contributing factor to risk at this stage.

A meta-analysis of the neural substrates of monetary reward anticipation and outcome in alcohol use disorder

The capacity to anticipate and detect rewarding outcomes is fundamental for the development of adaptive decision-making and goal-oriented behavior. Delineating the neural correlates of different stages of reward processing is imperative for understanding the neurobiological mechanism underlying alcohol use disorder (AUD). To examine the neural correlates of monetary anticipation and outcome in AUD patients, we performed two separate voxel-wise meta-analyses of functional neuroimaging studies, including 12 studies investigating reward anticipation and 7 studies investigating reward outcome using the monetary incentive delay task. During the anticipation stage, AUD patients displayed decreased activation in response to monetary cues in mesocortical-limbic circuits and sensory areas, including the ventral striatum (VS), insula, hippocampus, inferior occipital gyrus, supramarginal gyrus, lingual gyrus and fusiform gyrus. During the outcome stage, AUD patients exhibited reduced activation in the dorsal striatum, VS and insula, and increased activation in the orbital frontal cortex and medial temporal area. Our findings suggest that different activation patterns are associated with nondrug rewards during different reward processing stages, potentially reflecting a changed sensitivity to monetary reward in AUD.

Reward Processing in Alcohol-Dependent Patients and First-Degree Relatives: Functional Brain Activity During Anticipation of Monetary Gains and Losses

BACKGROUND

According to the reward deficiency syndrome and allostatic hypotheses, hyposensitivity of mesocorticolimbic regions to non-alcohol-related stimuli predisposes to dependence or is long-lastingly enhanced by chronic substance use. To date, no study has directly compared mesocorticolimbic brain activity during non-drug reward anticipation between alcohol-dependent, at risk, and healthy subjects.

METHODS

Seventy-five abstinent alcohol-dependent human subjects (mean abstinence duration 957.66 days), 62 healthy first-degree relatives of alcohol-dependent individuals, and 76 healthy control subjects without family history of alcohol dependence performed a monetary incentive delay task. Functional magnetic resonance imaging data of the anticipation phase were analyzed, during which visual cues predicted that fast response to a target would result in monetary gain, avoidance of monetary loss, or a neutral outcome.

RESULTS

During gain anticipation, there were no significant group differences. During loss anticipation, abstinent alcohol-dependent subjects showed lower activity in the left anterior insula compared with healthy control subjects without family history of alcohol dependence only (Montreal Neurological Institute [MNI] -25 19 -5; t₂₀₆ = 4.17, familywise error corrected p = .009). However, this effect was no longer significant when age was included as a covariate. There were no group differences between abstinent alcohol-dependent subjects and healthy first-degree relatives or between healthy first-degree relatives and healthy control subjects during loss anticipation, respectively.

CONCLUSIONS

Neither the neural reward deficiency syndrome nor the allostatic hypotheses are supported by the results. Future studies should investigate whether the incentive salience hypothesis allows for more accurate predictions regarding mesocorticolimbic brain activity of subjects with alcohol dependence and healthy individuals during reward and loss anticipation and further examine the neural substrates underlying a predisposition to dependence.

Common and Distinct Neural Correlates of Intertemporal and Risky Decision-Making: Meta-Analytical Evidence for the Dual-System Theory

The relationship between intertemporal and risky decision-making has received considerable attention in decision research. Single-process theories suggest that choices involving delay and risk are simply two manifestations of the same psychological mechanism, which implies similar patterns of neural activation. Conversely, the dual-system theory suggests that delayed and risky choices are two contrasting types of processes, which implies distinct brain networks. How these two types of choices relate to each other remains unclear. The current study addressed this issue by performing a meta-analysis of 28 intertemporal decision-making studies (862 subjects) and 51 risky decision-making studies (1539 subjects). We found no common area activated in the conjunction analysis of the delayed and risky rewards. Based on the contrast analysis, delayed rewards were associated with stronger activation in the left dorsal insula, while risky rewards were associated with activation in the bilateral ventral striatum and the right anterior insula. The results align with the dual-system theory with separate neural networks for delayed and risky rewards.

Neural substrates of motivational dysfunction across neuropsychiatric conditions: Evidence from meta-analysis and lesion network mapping

Motivational dysfunction constitutes one of the fundamental dimensions of psychopathology cutting across traditional diagnostic boundaries. However, it is unclear whether there is a common neural circuit responsible for motivational dysfunction across neuropsychiatric conditions. To address this issue, the current study combined a meta-analysis on psychiatric neuroimaging studies of reward/loss anticipation and consumption (4308 foci, 438 contrasts, 129 publications) with a lesion network mapping approach (105 lesion cases). Our meta-analysis identified transdiagnostic hypoactivation in the ventral striatum (VS) for clinical/at-risk conditions compared to controls during the anticipation of both reward and loss. Moreover, the VS subserves a key node in a distributed brain network which encompasses heterogeneous lesion locations causing motivation-related symptoms. These findings do not only provide the first meta-analytic evidence of shared neural alternations linked to anticipatory motivation-related deficits, but also shed novel light on the role of VS dysfunction in motivational impairments in terms of both network integration and psychological functions. Particularly, the current findings suggest that motivational dysfunction across neuropsychiatric conditions is rooted in disruptions of a common brain network anchored in the VS, which contributes to motivational salience processing rather than encoding positive incentive values.

Nucleus Accumbens Response to Reward among Children with a Family History of Alcohol Use Problems: Convergent Findings from the ABCD Study® and Michigan Longitudinal Study

Having a family history of alcohol use problems (FH+) conveys risk for alcohol use in offspring. Reward-related brain functioning may play a role in this vulnerability. The present study investigated brain function in the nucleus accumbens (NAcc) associated with the anticipation of reward in youth with two biological parents with alcohol use problems (FH+2), one biological parent with alcohol use problems (FH+1), and no biological parents with alcohol use problems (FH-). Participants were from the large, national Adolescent Brain Cognitive Development (ABCD) Study (mean age: 9.93; 48% female; FH+2 n = 223, FH+1 n = 1447, FH- n = 9690) and the Michigan Longitudinal Study (MLS), consisting of community-recruited families with high rates of alcohol use disorder (mean age: 10.54; 39.3% female; FH+2 n = 40, FH+1 n = 51, FH- n = 40). Reward anticipation was measured by the monetary incentive delay task. Regression models were used to assess associations between FH status and the anticipation of large rewards in right and left NAcc regions of interest. In both studies, FH+2 youth showed blunted anticipatory reward responding in the right NAcc compared to FH+1 youth. In the MLS, FH+2 youth also had blunted anticipatory reward responding in the right NAcc compared to the FH- group. Convergent results across two separate samples provide insights into a unique vulnerability of FH+2 youth and suggest that binary FH+ versus FH- categorizations may obscure important differences within FH+ youth.

Brain responses during delay discounting in youth at high-risk for substance use disorders

Offspring of parents with substance use disorders (SUD) discount future rewards at a steeper rate on the monetary delay discounting task (DD) than typically developing youth. However, brain activation during DD has yet to be studied in drug naïve youth with a family history (FH) of SUD. Here, we investigate brain activation differences in high-risk youth during DD. We recruited substance naïve youth, aged 11-12, into three groups to compare brain activation during DD: (1) High-risk youth (n = 35) with a FH of SUD and externalizing psychiatric disorders, (2) psychiatric controls (n = 25) who had no FH of SUD, but with equivalent externalizing psychiatric disorders as high-risk youth, and (3) a healthy control group (n = 24) with no FH of SUD and minimal psychopathology. A whole-brain voxel wise analysis of the [Delay > Baseline], [Immediate > Baseline], and [Control > Baseline] contrasts identified functional regions of interest, from which extracted parameter estimates were tested for significant group differences. Relative to control youth, high-risk youth showed stronger activation in the left posterior insula and thalamus when making delayed choices, and stronger activation of the parahippocampal gyrus when making both delayed and control choices (ps < 0.05). Activation in the left posterior insula negatively correlated with both subscales of the Emotion Regulation Checklist, and positively correlated with the Stroop interference effect (ps < 0.05). Our findings suggest possible heritable SUD risk neural markers that distinguish drug naïve high-risk youth from psychiatric and healthy controls.

Child reward neurocircuitry and parental substance use history: Findings from the Adolescent Brain Cognitive Development Study

BACKGROUND

Substance use research has focused on family history of alcohol use disorders but less on other addictions in biological family members. We examined how parental substance use history relates to reward system functioning, specifically nucleus accumbens (NAcc) and putamen activation at age 9-10 in the Adolescent Brain Cognitive Development (ABCD) Study. This research hopes to address limitations in prior literature by focusing analyses on a large, substance-naïve sample.

METHOD

We included ABCD participants with valid Monetary Incentive Delay task fMRI Baseline data and parent substance use history at project baseline from Data Release 2.0 (N = 10,622). Parent-history-positive (PH+) participants had one or both biological parents with a history of two+problems with alcohol (n = 741; PH+A) and/or other drugs (n = 638; PH+D). Of participants who were parent-history-negative (PH-) for alcohol and/or drugs, a stratified random sample based on six sociodemographic variables was created and matched to the PH+group (PH-A n = 699; PH-D n = 615). The contrast of interest was anticipation of a large reward vs. neutral response.

RESULTS

PH+A youth had more activation in the right NAcc during large reward anticipation than PH-A. PH+D youth showed enhanced left putamen activation during large reward anticipation than PH-D youth. Bayesian hypothesis testing showed moderate evidence (BF > 3) in favor of the null hypothesis.

CONCLUSION

These findings suggest that pre-adolescents whose biological parents had a history of substance-related problems show small differences in reward processing compared to their PH- peers.

Trajectories of brain development reveal times of risk and factors promoting resilience to alcohol use during adolescence

Alcohol use disorder (AUD) is recognized as harmful for the developing brain. Numerous studies have sought environmental and genetic risk factors that predict the development of AUD, but recently identified resilience factors have emerged as protective. This chapter reviews normal processes of brain development in adolescence and emerging adulthood, delineates disturbed growth neurotrajectories related to heavy drinking, and identifies potential endogenous, experiential, and time-linked brain markers of resilience. For example, concurrent high dorsolateral prefrontal activation serving inhibitory control and low nucleus accumbens activation serving reward functions engender positive adaptation and low alcohol use. Also discussed is the role that moderating factors have in promoting risk for or resilience to AUD. Longitudinal research on the effects of all levels of alcohol drinking on the developing brain remains crucial and should be pursued in the context of resilience, which is a promising direction for identifying protective biomarkers against developing AUDs.

Avoiding monetary loss: A human habenula functional MRI ultra-high field study

A number of convergent human neuroimaging and animal studies suggest that habenula neurons fire in anticipation of non-rewarding outcomes, and suppress their firing in anticipation of rewarding outcomes. This normative function of the habenula appears disrupted in depression, and may be critical to the anti-depressant effects of ketamine. However, studying habenula functionality in humans using standard 3 T MRI is inherently limited by its small size. We employed ultra-high field (7 T) fMRI to investigate habenular activity in eighteen healthy volunteers during a Monetary Incentive Delay Task, focussing on loss avoidance, monetary loss and neutral events. We assessed neural activation in the field of view (FOV) in addition to ROI-based habenula-specific activity and generalized task-dependent functional connectivity. Whole FOV results indicated substantial neural differences between monetary loss and neutral outcomes, as well as between loss avoidance and neutral outcomes. Habenula-specific analyses showed bilateral deactivation during loss avoidance, compared to other outcomes. This first investigation into the habenula's role during loss avoidance revealed that the left habenula further differentiated between loss avoidance and monetary loss. Functional connectivity between the right habenula and the ipsilateral hippocampus and subcallosal cingulate (regions implicated in memory and depression pathophysiology) was enhanced when anticipating potential losses compared to anticipating neutral outcomes. Our findings suggest that the human habenula responds most strongly to outcomes of loss avoidance when compared to neutral and monetary losses, suggesting a role for the habenula in both reward and aversive processing. This has critical relevance to understanding the pathophysiology of habenula function in mood and other neuropsychiatric disorders, as well as the mechanism of action of habenula-targeting antidepressants such as ketamine.

Social neural sensitivity as a susceptibility marker to family context in predicting adolescent externalizing behavior

Adolescence represents a period of risk for developing patterns of risk-taking and conduct problems, and the quality of the family environment is one robust predictor of such externalizing behavior. However, family factors may not affect all youth uniformly, and individual differences in neurobiological susceptibility to the family context may moderate its influence. The current study investigated brain-based individual differences in social motivational processing as a susceptibility marker to family conflict in predicting externalizing behavior in early adolescent youth. 163 adolescents (M_age = 12.87 years) completed an fMRI scan during which they anticipated social rewards and social punishments. For adolescents with heightened ventral striatum and amygdala blood oxygen-level dependent (BOLD) response during the anticipation of social rewards and heightened ventral striatum BOLD response during the anticipation of social punishments, higher levels of family conflict were associated with greater externalizing behavior. BOLD response when anticipating both social rewards and punishments suggested increased susceptibility to maladaptive family contexts, highlighting the importance of considering adolescent social motivation in positive and negatively valenced contexts.

Neural reward circuit dysfunction as a risk factor for bipolar spectrum disorders and substance use disorders: A review and integration

Bipolar spectrum disorders (BSDs) and substance use disorders (SUDs) are associated with neural reward dysfunction. However, it is unclear what pattern of neural reward function underlies pre-existing vulnerability to BSDs and SUDs, or whether neural reward function explains their high co-occurrence. The current paper provides an overview of the separate literatures on neural reward sensitivity in BSDs and SUDs. We provide a systematic review of 35 studies relevant to identifying neural reward function vulnerability to BSDs and SUDs. These studies include those examining neural reward processing on a monetary reward task with prospective designs predicting initial onset of SUDs, familial risk studies that examine unaffected offspring or first-degree relatives of family members with BSDs or SUDs, and studies that examine individuals with BSDs or SUDs who are not currently in an episode of the disorder. Findings from the review highlight that aberrant responding and connectivity across neural regions associated with reward and cognitive control confers risk for the development of BSDs and SUDs. Discussion focuses on limitations of the extant literature. We conclude with an integration and theoretical model for understanding how aberrant neural reward responding may constitute a vulnerability to the development of both BSDs and SUDs.

Subtypes of inhibitory and reward activation associated with substance use variation in adolescence: A latent profile analysis of brain imaging data

The present study identified subgroups based on inhibitory and reward activation, two key neural functions involved in risk-taking behavior, and then tested the extent to which subgroup differences varied by age, sex, behavioral and familial risk, and substance use. Participants were 145 young adults (18-21 years old; 40.0% female) from the Michigan Longitudinal Study. Latent profile analysis (LPA) was used to establish subgroups using task-based brain activations. Demographic and substance use differences between subgroups were then examined in logistic regression analyses. Whole-brain task activations during a functional magnetic resonance imaging go/no-go task and monetary incentive delay task were used to identify beta weights as input for LPA modeling. A four-class model showed the best fit with the data. Subgroups were categorized as: (1) low inhibitory activation/moderate reward activation (39.7%), (2) moderate inhibitory activation/low reward activation (22.7%), (3) moderate inhibitory activation/high reward activation (25.2%), and (4) high inhibitory activation/high reward activation (12.4%). Compared with the other subgroups, Class 2 was older, less likely to have parental alcohol use disorder, and had less alcohol use. Class 4 was the youngest and had greater marijuana use. Classes 1 and 3 did not differ significantly from the other subgroups. These findings demonstrate that LPA applied to brain activations can be used to identify distinct neural profiles that may explain heterogeneity in substance use outcomes and may inform more targeted substance use prevention and intervention efforts.

Interactions between methodological and interindividual variability: How Monetary Incentive Delay (MID) task contrast maps vary and impact associations with behavior

INTRODUCTION

Phenomena related to reward responsiveness have been extensively studied in their associations with substance use and socioemotional functioning. One important task in this literature is the Monetary Incentive Delay (MID) task. By cueing and delivering performance-contingent reward, the MID task has been demonstrated to elicit robust activation of neural circuits involved in different phases of reward responsiveness. However, systematic evaluations of common MID task contrasts have been limited to between-study comparisons of group-level activation maps, limiting their ability to directly evaluate how researchers' choice of contrasts impacts conclusions about individual differences in reward responsiveness or brain-behavior associations.

METHODS

In a sample of 104 participants (Age Mean = 19.3, SD = 1.3), we evaluate similarities and differences between contrasts in: group- and individual-level activation maps using Jaccard's similarity index, region of interest (ROI) mean signal intensities using Pearson's r, and associations between ROI mean signal intensity and psychological measures using Bayesian correlation.

RESULTS

Our findings demonstrate more similarities than differences between win and loss cues during the anticipation contrast, dissimilarity between some win anticipation contrasts, an apparent deactivation effect in the outcome phase, likely stemming from the blood oxygen level-dependent undershoot, and behavioral associations that are less robust than previously reported.

CONCLUSION

Consistent with recent empirical findings, this work has practical implications for helping researchers interpret prior MID studies and make more informed a priori decisions about how their contrast choices may modify results.

Substance Use Initiation, Particularly Alcohol, in Drug-Naive Adolescents: Possible Predictors and Consequences From a Large Cohort Naturalistic Study

OBJECTIVE

It is unclear whether deviations in brain and behavioral development, which may underpin elevated substance use during adolescence, are predispositions for or consequences of substance use initiation. Here, we examine behavioral and neuroimaging indices at early and mid-adolescence in drug-naive youths to identify possible predisposing factors for substance use initiation and its possible consequences.

METHOD

Among 304 drug-naive adolescents at baseline (age 14 years) from the IMAGEN dataset, 83 stayed drug-naive, 133 used alcohol on 1 to 9 occasions, 42 on 10 to 19 occasions, 27 on 20 to 39 occasions, and 19 on >40 occasions at follow-up (age 16 years). Baseline measures included brain activation during the Monetary Incentive Delay task. Data at both baseline and follow-up included measures of trait impulsivity and delay discounting.

RESULTS

From baseline to follow-up, impulsivity decreased in the 0 and 1- to 9-occasions groups (p < .004), did not change in the 10- to 19-occasions and 20- to 29-occasions groups (p > .294), and uncharacteristically increased in the >40-occasions group (p = .046). Furthermore, blunted medial orbitofrontal cortex activation during reward outcome at baseline significantly predicted higher alcohol use frequency at follow-up, above and beyond behavioral and clinical variables (p = .008).

CONCLUSION

These results suggest that the transition from no use to frequent drinking in early to mid-adolescence may disrupt normative developmental changes in behavioral control. In addition, blunted activity of the medial orbitofrontal cortex during reward outcome may underscore a predisposition toward the development of more severe alcohol use in adolescents. This distinction is clinically important, as it informs early intervention efforts in preventing the onset of substance use disorder in adolescents.

Better the devil you know than the devil you don't: Neural processing of risk and ambiguity

Risk and ambiguity are inherent in virtually all human decision-making. Risk refers to a situation in which we know the precise probability of potential outcomes of each option, whereas ambiguity refers to a situation in which outcome probabilities are not known. A large body of research has shown that individuals prefer known risks to ambiguity, a phenomenon known as ambiguity aversion. One heated debate concerns whether risky and ambiguous decisions rely on the same or distinct neural circuits. In the current meta-analyses, we integrated the results of neuroimaging research on decision-making under risk (n = 69) and ambiguity (n = 31). Our results showed that both processing of risk and ambiguity showed convergence in anterior insula, indicating a key role of anterior insula in encoding uncertainty. Risk additionally engaged dorsomedial prefrontal cortex (dmPFC) and ventral striatum, whereas ambiguity specifically recruited the dorsolateral prefrontal cortex (dlPFC), inferior parietal lobe (IPL) and right anterior insula. Our findings demonstrate overlapping and distinct neural substrates underlying different types of uncertainty, guiding future neuroimaging research on risk-taking and ambiguity aversion.

Binge drinking is associated with altered resting state functional connectivity of reward-salience and top down control networks

Binge drinking is characterized by bouts of high-intensity alcohol intake and is associated with an array of health-related harms. Even though the transition from occasional impulsive to addictive alcohol use is not well understood, neurobiological models of addiction suggest that repeated cycles of intoxication and withdrawal contribute to the development of addiction in part through dysregulation of neurofunctional networks. Research on the neural sequelae associated with binge drinking is scant but resting state functional connectivity (RSFC) studies of alcohol use disorders (AUD) indicate that the development and maintenance of long-term excessive drinking may be mediated by network-level disruptions. The present study examined RSFC in young adult binge (BD) and light (LD) drinkers with seeds representing the networks subserving reward (the nucleus accumbens and caudate nucleus), salience (anterior cingulate cortex, ACC), and executive control (inferior frontal cortex, IFC). BDs exhibited enhanced connectivity between the striatal reward areas and the orbitofrontal cortex and the ACC, which is consistent with AUD studies and may be indicative of alcohol-motivated appetitive behaviors. Conversely, BDs demonstrated lower connectivity between the IFC and hippocampus which was associated with higher craving. This may indicate impaired ability to suppress unwanted thoughts and a failure to employ memory of the harmful consequences of heavy drinking in prospective plans and intentions. The observed greater connectivity of the reward/salience network and the lower prefrontal-hippocampal connectivity were associated with hazardous drinking levels indicating that dysregulation of neurofunctional networks may underlie binge drinking patterns.

Delay discounting and neurocognitive correlates among inner city adolescents with and without family history of substance use disorder

Adolescents with a family history (FH+) of substance use disorder (SUD) are at a greater risk for SUD, suggested to be partly due to the transmission of behavioral impulsivity. We used a delay discounting task to compare impulsivity in decision-making and its associated brain functioning among FH+ and FH - minority adolescents. Participants chose between Smaller Sooner (SS) and Larger Later (LL) rewards. The SS was available immediately (Now trials) or in the future (Not-Now trials), allowing for greater differentiation between impulsive decisions. The FH+ group showed greater impatience by responding SS more frequently than the FH - group, only on the Now trials, and even when the relative reward differences (RRD) increased. Surprisingly, there were no differences in brain activity between the groups. Combined, the groups showed greater reward activity during the Now vs. Not-Now trials in medial prefrontal/anterior cingulate, posterior cingulate, precuneus, and inferior frontal gyrus (i.e., an immediacy effect). As the RRD increased activation in the reward network decreased, including the striatum, possibly reflecting easy decision-making. These results indicate that risk for SUD, seen behaviorally among FH+ adolescents, may not yet be associated with discernable brain changes, suggesting that early intervention has the potential to reduce this risk.

The ups and downs of relating nondrug reward activation to substance use risk in adolescents

Purpose of review

A wealth of epidemiological and cohort research, together with a healthy dose of anecdote, has characterized late-adolescence and emerging adulthood as a time of increased substance use and other risky behaviors. This review will address whether differences between adolescents or between adolescents and other age groups in dopaminergic mesolimbic recruitment by (non-drug) rewards inferred from functional magnetic resonance imaging (fMRI) could partially explain morbidity and mortality from risky-behavior-related causes in adolescents.

Recent findings

Recent findings do not suggest a definitive directionality with regard to whether increased vs decreased mesolimbic responsiveness to nondrug rewards correlates with real-world risk-taking. Inconsistent relationships between reward-activation and real-world risky behavior in these reports reflect in part methodological differences as well as conceptual differences between populations in terms of whether tepid mesolimbic recruitment by rewards is a marker of psychiatric health.

Summary

There are several potential reasons why the directionality of relationships between reward-elicited brain activation and substance use risk (specifically) might differ. These factors include differences between adolescents in histories/exposure of substance use, motivation for substance use, the component of the instrumental behavior being studied, and the cognitive demands of the incentive tasks. Systematic manipulation of these discrepant study factors might offer a way forward to clarify how motivational neurocircuit function relates to addiction risk in adolescents.

Effects of substance misuse on reward-processing in patients with attention-deficit/hyperactivity disorder

Attention-Deficit/Hyperactivity Disorder (ADHD) and Substance Use Disorder (SUD) often co-occur and are associated with treatment resistance. Both disorders are characterized by similar reward-processing deficits with decreased striatal responses to reward anticipation, though literature is inconsistent. It is unclear whether substance misuse exaggerates reward-processing deficits observed in ADHD. The aim of this study was to examine substance misuse effects on reward-processing in ADHD. Functional MRI data in a Monetary Incentive Delay (MID) task from a multi-site study were compared across ADHD groups with and without substance misuse (ADHD + SM and ADHD-only, respectively) and healthy controls (n = 40/group, 74 males and 46 females, aged 13.7-25.9 years). Substance misuse was defined as misuse of alcohol, nicotine, or drugs. Groups were matched with presence/absence of parental SUD to avoid interference with SUD trait effects. Compared to ADHD-only and controls, ADHD + SM showed hyperactivation in putamen during reward anticipation. Compared to controls, the ADHD groups showed hypoactivation in motor/sensory cortices and hyperactivation in frontal pole and OFC during reward outcome. ADHD + SM also showed hyperactivation in frontal pole during neutral outcome. Moreover, ADHD + SM patients showed higher callous-unemotional (CU) traits that were positively correlated with putamen responses to reward anticipation. Our results show distinct condition-independent neural activation profile for ADHD + SM compared to ADHD-only and controls. Effects of comorbid substance misuse and variability of its prevalence across ADHD studies might have contributed to inconsistencies in ADHD literature. Contrasted with findings for reward-processing in SUD literature, results potentially suggest distinct underlying mechanisms for SUD subgroups with different characteristics, like antisocial/psychopathic traits.

Altered Neural Processing of Reward and Punishment in Women With Methamphetamine Use Disorder

It has been suggested that the altered function of reward and punishment is an important vulnerability factor leading to the development of drug use disorders. Previous studies have identified evidence of neurophysiological dysfunction in the reward process of individuals with substance use disorders. To date, only a few event-related potential (ERP) studies have examined the neural basis of reward and punishment processing in women with methamphetamine (MA) use disorders. The current ERP research aims to investigate the neurophysiological mechanisms of reward and punishment in women with MA use disorder using a monetary incentive delay task. Nineteen women with MA use disorder (MA group) and 20 healthy controls (HC group) were recruited in this study. The behavioral data showed that the reaction time (RT) was faster and the response accuracy (ACC) was higher for the potential reward and punishment conditions compared to neutral conditions. During the monetary incentive anticipation stage, the Cue-P3, and stimulus-preceding negativity (SPN) were larger in the MA group than in the HC group. The SPN under the potential reward condition was larger than that under the neutral condition in the MA group but not in the HC group. During the monetary incentive consummation stage, the feedback-related negativity and feedback P3 (FB-P3) following positive feedback were significantly larger than negative feedback in the potential reward condition for the HC group, but not for the MA group. However, the FB-P3 following negative feedback was significantly larger than positive feedback in the potential punishment condition for the MA group, but not the HC group. The results suggest that women with MUD have stronger expectations of generic reward and stronger response of generic harm avoidance, which could be targeted in designing interventions for women with MA use disorder.

Spatial migration of human reward processing with functional development: Evidence from quantitative meta-analyses

Functional magnetic resonance imaging (fMRI) studies have shown notable age‐dependent differences in reward processing. We analyzed data from a total of 554 children, 1,059 adolescents, and 1,831 adults from 70 articles. Quantitative meta‐analyses results show that adults engage an extended set of regions that include anterior and posterior cingulate gyri, insula, basal ganglia, and thalamus. Adolescents engage the posterior cingulate and middle frontal gyri as well as the insula and amygdala, whereas children show concordance in right insula and striatal regions almost exclusively. Our data support the notion of reorganization of function over childhood and adolescence and may inform current hypotheses relating to decision‐making across age.

Reward-Related Brain Activity Prospectively Predicts Increases in Alcohol Use in Adolescents

OBJECTIVE

Altered activity within reward-related neural regions, including the ventral striatum (VS) and medial prefrontal cortex (mPFC), is associated with concurrent problematic substance use. The aims of the present study were (a) to identify patterns of reward-related neural activity that prospectively predicted changes in alcohol use 2 years after magnetic resonance imaging in a sample of adolescents, and (b) to examine whether these patterns differed by sex. We also tested whether depression symptoms or impulsivity mediated associations between neural activity and future alcohol use.

METHOD

Participants were 262 adolescents (129 male and 133 female) of Mexican origin who completed the Monetary Incentive Delay task during a functional magnetic resonance imaging scan at age 16. Participants reported on their alcohol use at ages 16 and 18.

RESULTS

Results indicated that different patterns of reward-related neural activity predicted future increases in alcohol use for male and female adolescents. In boys, higher VS activity during reward anticipation and average ventral mPFC activity during reward feedback predicted increases in alcohol use from age 16 to 18 years; in girls, higher dorsal mPFC activity and blunted VS activity during reward anticipation predicted increases in alcohol use from age 16 to 18 years. Depression symptoms or impulsivity did not mediate these associations.

CONCLUSION

The results suggest that different pathways of risk may lead to problematic alcohol use for adolescent boys and girls. These sex differences in neural risk pathways have important implications for prevention and intervention approaches targeting Mexican-origin youth.

Neural circuitry and mechanisms of waiting impulsivity: relevance to addiction

Impatience-the failure to wait or tolerate delayed rewards (e.g. food, drug and monetary incentives)-is a common behavioural tendency in humans. However, when rigidly and rapidly expressed with limited regard for future, often negative consequences, impatient or impulsive actions underlie and confer susceptibility for such diverse brain disorders as drug addiction, attention-deficit hyperactivity disorder (ADHD) and major depressive disorder. Consequently, 'waiting' impulsivity has emerged as a candidate endophenotype to inform translational research on underlying neurobiological mechanisms and biomarker discovery for many of the so-called impulse-control disorders. Indeed, as reviewed in this article, this research enterprise has revealed a number of unexpected targets and mechanisms for intervention. However, in the context of drug addiction, impulsive decisions that maximize short-term gains (e.g. acute drug consumption) over longer-term punishment (e.g. unemployment, homelessness, personal harm) defines one aspect of impulsivity, which may or may not be related to rapid, unrestrained actions over shorter timescales. We discuss the relevance of this distinction in impulsivity subtypes for drug addiction with reference to translational research in humans and other animals. This article is part of the theme issue 'Risk taking and impulsive behaviour: fundamental discoveries, theoretical perspectives and clinical implications'.

Family history of alcohol use disorder is associated with brain structural and functional changes in healthy first-degree relatives

Background:

Neuroimaging studies of vulnerability to Alcohol Use Disorder (AUD) have identified structural and functional variations which might reflect inheritable features in alcohol-naïve relatives of AUD individuals (FH+) compared to controls having no such family history (FH-). However, prior research did not simultaneously account for childhood maltreatment, any clinically significant disorder and maternal AUD. Therefore, we mainly aimed to investigate the brain structure and reward-related neural activations (fMRI), using whole-brain analysis in FH+ young adults with no prevalent confounders.

Methods:

46 FH+ and 45 FH- male and female participants had no severe childhood maltreatment exposure, neither any psychiatric disorder or AUD, nor a prenatal exposure to maternal AUD. We used a 3 T MRI coupled with a whole brain voxel-based method to compare between groups the grey matter volumes and activations in response to big versus small wins during a Monetary Incentive Delay task. The Childhood Trauma Questionnaire score was used as confounding variable in the analyses to account for the remaining variance between groups.

Results:

Compared to FH- controls, FH+ participants had smaller grey matter volumes in the frontal and cingulate regions as well as in the bilateral nucleus accumbens and right insula. The FH+ participants’ fMRI datasets denoted a blunted activation in the middle cingulum with respect to FH- controls’ during the processing of reward magnitude, and a greater activation in the anterior cingulum in response to anticipation of a small win.

Conclusions:

Family history of alcohol use disorder is linked to structural and functional variations including brain regions involved in reward processes.

The effect of alcohol use on neuroimaging correlates of cognitive and emotional processing in human adolescence

OBJECTIVE

This article provides an overview of the scientific literature pertaining to the effects of alcohol on neural correlates of cognitive and emotional functioning, including reward processing and cue-reactivity, in adolescence and young adulthood.

METHOD

Peer-reviewed, original research articles that included a neuroimaging assessment of alcohol effects on subsequent cognitive or emotional processing in adolescent or young adult samples were searched (through November 2018) and summarized in the review.

RESULTS

Cross-sectional studies provided early evidence of alcohol-related differences in neural processing across a number of cognitive domains. Longitudinal studies have identified neural abnormalities that predate drinking within most domains of cognitive functioning, while a few neural alterations have been observed within the domains of visual working memory, inhibitory control, reward processing, and cue-reactivity that appear to be related to the neurotoxic effect of alcohol use during adolescence. In contrast, neural correlates of emotion functioning appear to be relatively stable to the effects of alcohol.

CONCLUSIONS

Larger prospective studies are greatly needed to disentangle premorbid factors from neural consequences associated with drinking, and to detect subsets of youth who may be particularly vulnerable to alcohol's effects on cognitive and emotional functioning. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Genetic Selection for Alcohol Preference in Mice Alters Dorsal Striatum Neurotransmission

BACKGROUND

Although it is widely acknowledged that the risk of developing an alcohol use disorder (AUD) is strongly influenced by genetic factors, very little is known about how this genetic predisposition may alter neurotransmission in a way that promotes AUD susceptibility. The dorsal striatum has garnered increased attention as a brain region of interest in AUD development given its significant roles in goal-directed and habitual behavior.

METHODS

In the present work, dorsal striatal neurotransmission parameters were measured in preclinical mouse models of high and low AUD risk. We performed brain slice whole-cell patch clamp electrophysiological recordings from medium spiny neurons (MSNs) in the dorsomedial (DMS) and dorsolateral (DLS) striatum of naïve adult male and female selectively bred high- and low-alcohol-preferring lines of mice (HAP and LAP).

RESULTS

We found that MSNs of HAP mice were significantly more excitable than those of LAP mice, specifically in the DLS. Additionally, the frequencies of spontaneous glutamate- and GABA-mediated currents were both elevated in HAP mice relative to LAP mice in both dorsal striatal subregions, whereas amplitude differences were more variable between lines and subregions. AMPAR/NMDAR current ratios were significantly lower in HAP mice in both DLS and DMS.

CONCLUSIONS

Collectively, these results suggest that genetic predisposition for high or low alcohol consumption produces significantly different basal functional states within both DLS and DMS which may be important factors in the behavioral phenotypes of HAP and LAP mice.

Love is analogous to money in human brain: Coordinate-based and functional connectivity meta-analyses of social and monetary reward anticipation

Both social and material rewards play a crucial role in daily life and function as strong incentives for various goal-directed behaviors. However, it remains unclear whether the incentive effects of social and material reward are supported by common or distinct neural circuits. Here, we have addressed this issue by quantitatively synthesizing and comparing neural signatures underlying social (21 contrasts, 207 foci, 696 subjects) and monetary (94 contrasts, 1083 foci, 2060 subjects) reward anticipation. We demonstrated that social and monetary reward anticipation engaged a common neural circuit consisting of the ventral tegmental area, ventral striatum, anterior insula, and supplementary motor area, which are intensively connected during both task and resting states. Functional decoding findings indicate that this generic neural pathway mediates positive value, motivational relevance, and action preparation during reward anticipation, which together motivate individuals to prepare well for the response to the upcoming target. Our findings support the common neural currency hypothesis by providing the first meta-analytic evidence to quantitatively show the common involvement of brain regions in both social and material reward anticipation.

Effects of familial risk and stimulant drug use on the anticipation of monetary reward: an fMRI study

The association between stimulant drug use and aberrant reward processing is well-documented in the literature, but the nature of these abnormalities remains elusive. The present study aims to disentangle the separate and interacting effects of stimulant drug use and pre-existing familial risk on abnormal reward processing associated with stimulant drug addiction. We used the Monetary Incentive Delay task, a well-validated measure of reward processing, during fMRI scanning in four distinct groups: individuals with familial risk who were either stimulant drug-dependent (N = 41) or had never used stimulant drugs (N = 46); and individuals without familial risk who were either using stimulant drugs (N = 25) or not (N = 48). We first examined task-related whole-brain activation followed by a psychophysiological interaction analysis to further explore brain functional connectivity. For analyses, we used a univariate model with two fixed factors (familial risk and stimulant drug use). Our results showed increased task-related activation in the putamen and motor cortex of stimulant-using participants. We also found altered task-related functional connectivity between the putamen and frontal regions in participants with a familial risk (irrespective of whether they were using stimulant drugs or not). Additionally, we identified an interaction between stimulant drug use and familial risk in task-related functional connectivity between the putamen and motor-related cortical regions in potentially at-risk individuals. Our findings suggest that abnormal task-related activation in motor brain systems is associated with regular stimulant drug use, whereas abnormal task-related functional connectivity in frontostriatal brain systems, in individuals with familial risk, may indicate pre-existing neural vulnerability for developing addiction.

Neurophysiological Correlates and Differential Drug Response in Subjects With a Family History of an Alcohol Use Disorder

A family history of an alcohol use disorder (AUD) has been shown to increase one's risk of developing an AUD. Additionally, a positive family history of AUD (family history positive (FHP)) has neurobiological and neuropsychopharmacological consequences, and this review summarizes differential drug response as well as neuroanatomical and neurocognitive correlates. FHP status is related to altered responses to a number of drugs, including substances with abuse liability like alcohol, opioids, amphetamines, and ketamine. FHP individuals demonstrate fewer aversive effects and more rewarding response to both alcohol and subanesthetic dose ketamine. Ketamine is a rapid-acting antidepressant, and several studies have reported that ketamine is more effective for FHP treatment-resistant depressed individuals. In short, the reviewed neurophysiological differences may contribute to ketamine's enhanced antidepressant efficacy in FHP patients. Volumetric differences in the amygdala, nucleus accumbens, neocortex, and cerebellum are commonly reported. Furthermore, FHP has also been associated with altered neurocognitive performance, e.g., increased impulsivity. The imaging and psychological literature supports a neurodevelopmental lag hypothesis in FHP youth. The review will further discuss these findings in depth.

Reward activation in childhood predicts adolescent substance use initiation in a high-risk sample

BACKGROUND

Substance use at an early age conveys substantial risk for later substance-related problems. A better understanding of early risk factors could result in more timely and effective intervention. This study investigated the predictive utility of the brain's response to reward anticipation as a risk factor for early substance use initiation.

METHODS

Participants were 34 children (25 male) at high risk for alcohol and other substance use disorders from a longitudinal functional magnetic resonance imaging study, scanned at a mean age of 10.5 years (SD = 1.2) when participants were substance-naïve. We used a monetary incentive delay task to examine the hemodynamic response of the nucleus accumbens to gain and loss anticipation. Logistic regression was used to test the hypothesis that these brain response patterns would have predictive utility over and above early externalizing behaviors and family history of substance use disorder, two key risk factors for substance use problems, in differentiating those who initiated substance use before age 16 (n = 18) and those who did not (n = 16).

RESULTS

Greater nucleus accumbens activation during monetary gain anticipation in childhood increased the likelihood of initiating substance use during early adolescence (p = .023). The model that comprised neural data in addition to early externalizing behaviors and family history showed significantly better fit than the model without neural data (χ²₂ = 7.38, p = .025).

CONCLUSIONS

Heightened gain anticipation activation in the nucleus accumbens may predispose individuals to early substance use, beyond the risk conveyed by other known factors.

Review of Neurobiological Influences on Externalizing and Internalizing Pathways to Alcohol Use Disorder

Purpose of review

Two developmental courses through which alcohol use disorder (AUD) may emerge include externalizing and internalizing pathways. We review recent neuroimaging studies of potential neural risk factors for AUD and link findings to potential behavioral risk factors for AUD.

Recent findings

There is evidence that early-emerging weakness in prefrontal functioning and later-emerging differences in reward-system functioning contribute to an externalizing risk pathway. Stress may be an important contributor in the internalizing pathway through a blunting of reward-related activation, which may act alone or in combination with heightened emotion-related reactivity.

Summary

This review highlights areas for future work, including investigation of the relative balance between prefrontal and subcortical circuitry, attention to stages of AUD, and consideration of environmental factors such as stress and sleep. Particularly important is longitudinal work to understand the temporal ordering of associations among brain maturation, behavioral risk, and alcohol use.

Effects of adolescent alcohol consumption on the brain and behaviour

Per occasion, alcohol consumption is higher in adolescents than in adults in both humans and laboratory animals, with changes in the adolescent brain probably contributing to this elevated drinking. This Review examines the contributors to and consequences of the use of alcohol in adolescents. Human adolescents with a history of alcohol use differ neurally and cognitively from other adolescents; some of these differences predate the commencement of alcohol consumption and serve as potential risk factors for later alcohol use, whereas others emerge from its use. The consequences of alcohol use in human adolescents include alterations in attention, verbal learning, visuospatial processing and memory, along with altered development of grey and white matter volumes and disrupted white matter integrity. The functional consequences of adolescent alcohol use emerging from studies of rodent models of adolescence include decreased cognitive flexibility, behavioural inefficiencies and elevations in anxiety, disinhibition, impulsivity and risk-taking. Rodent studies have also showed that adolescent alcohol use can impair neurogenesis, induce neuroinflammation and epigenetic alterations, and lead to the persistence of adolescent-like neurobehavioural phenotypes into adulthood. Although only a limited number of studies have examined comparable measures in humans and laboratory animals, the available data provide evidence for notable across-species similarities in the neural consequences of adolescent alcohol exposure, providing support for further translational efforts in this context.

Neural and psychological characteristics of college students with alcoholic parents differ depending on current alcohol use

A significant proportion of college students are adult children of an alcoholic parent (ACoA), which can confer greater risk of depression, poor self-esteem, alcohol and drug problems, and greater levels of college attrition. However, some ACoA are resilient to these negative outcomes. The goal of this study was to better understand the psychobiological factors that distinguish resilient and vulnerable college-aged ACoAs. To do so, scholastic performance and psychological health were measured in ACoA college students not engaged in hazardous alcohol use (resilient) and those currently engaged in hazardous alcohol use (vulnerable). Neural activity (as measured by functional magnetic resonance imaging) in response to performing working memory and emotion-based tasks were assessed. Furthermore, the frequency of polymorphisms in candidate genes associated with substance use, risk taking and stress reactivity were compared between the two ACoA groups. College ACoAs currently engaged in hazardous alcohol use reported more anxiety, depression and posttraumatic stress symptoms, and increased risky nicotine and marijuana use as compared to ACoAs resistant to problem alcohol use. ACoA college students with current problem alcohol showed greater activity of the middle frontal gyrus and reduced activation of the posterior cingulate in response to visual working memory and emotional processing tasks, which may relate to increased anxiety and problem alcohol and drug behaviors. Furthermore, polymorphisms of cholinergic receptor and the serotonin transporter genes also appear to contribute a role in problem alcohol use in ACoAs. Overall, findings point to several important psychobiological variables that distinguish ACoAs based on their current alcohol use that may be used in the future for early intervention.

Shaping vulnerability to addiction - the contribution of behavior, neural circuits and molecular mechanisms

Substance use disorders continue to impose increasing medical, financial and emotional burdens on society in the form of morbidity and overdose, family disintegration, loss of employment and crime, while advances in prevention and treatment options remain limited. Importantly, not all individuals exposed to abused substances effectively develop the disease. Genetic factors play a significant role in determining addiction vulnerability and interactions between innate predisposition, environmental factors and personal experiences are also critical. Thus, understanding individual differences that contribute to the initiation of substance use as well as on long-term maladaptations driving compulsive drug use and relapse propensity is of critical importance to reduce this devastating disorder. In this paper, we discuss current topics in the field of addiction regarding individual vulnerability related to behavioral endophenotypes, neural circuits, as well as genetics and epigenetic mechanisms. Expanded knowledge of these factors is of importance to improve and personalize prevention and treatment interventions in the future.

Preliminary Evidence for Disrupted Nucleus Accumbens Reactivity and Connectivity to Reward in Binge Drinkers

AIMS

Dysfunctional brain reward circuitry, particularly in the nucleus accumbens (NAcc), has been proposed as a risk factor for alcohol use disorder (AUD). This risk factor may be evident in binge drinkers (BD), who are at high risk for developing AUD. We examined whole-brain and NAcc reactivity to reward in BD compared to non-binge drinkers (NBD), hypothesizing that groups would differ in their neural reactivity and connectivity.

METHODS

Healthy BD (N = 27) and NBD (N = 23)-none meeting AUD criteria-completed a reward-guessing game, the 'Doors' task, during functional magnetic resonance imaging. We conducted an exploratory whole-brain search for group differences, but given our a priori hypotheses, we also extracted activation from the NAcc to examine reactivity during reward (Win > Loss) and functional connectivity (FC) to the prefrontal cortex.

RESULTS

Compared to NBD, BD exhibited greater activation in both the right and left NAcc during reward relative to loss. Additionally, NBD drinkers exhibited positive FC between the NAcc and dorsal anterior cingulate (dACC) whereas the BD showed negative FC between these regions. Furthermore, less NAcc-dACC FC was related to more past month alcohol use.

CONCLUSIONS

Our results provide preliminary evidence that BD exhibit greater NAcc activation during reward receipt relative to loss. This is consistent with the broader AUD literature and suggests aberrant neural reactivity may precede disorder onset. In addition, BD exhibited less NAcc-dACC FC, perhaps reflecting deficient regulation of activation to rewards compared to losses. This profile of reward brain circuitry could represent neural correlates of vulnerability for AUD.

SHORT SUMMARY

Healthy binge drinkers, at risk for alcohol use disorder, exhibited greater nucleus accumbens activation during reward relative to loss. In addition, binge drinkers exhibited reduced connectivity between the nucleus accumbens and dorsal anterior cingulate, which was associated with more past month alcohol use.

Impulsive personality dimensions are associated with altered behavioral performance and neural responses in the monetary incentive delay task

Individual differences in dimensions of impulsivity personality including disinhibition and sensation seeking modulate approach responses to reinforcing stimuli, such as drugs and money. The current study examined the effects of monetary incentive on both behavioral performance and electrophysiological activity among individuals varying in disinhibition and sensation seeking. The monetary incentive delay (MID) task was completed under electroencephalogram (EEG) recording. Behavioral data showed that higher disinhibition and sensation-seeking were associated with lower performance accuracy. Event-related potential (ERP) data showed that high reinforcement cues elicited a larger late positive component (LPC) than other conditions among high disinhibition participants, indicating its strong emotional influence. Additionally, in the neutral incentive condition, the feedback-related negativity (FRN) elicited by correct outcomes was larger than that elicited by incorrect outcomes in the high disinhibition group only. This novel finding indicates that high disinhibition participants were less likely to expect correct outcomes compared to incorrect outcomes in the neutral incentive condition. Finally, the P3 component elicited by outcome presentation showed an interaction between two impulsivity dimensions; when disinhibition level was low, the P3 was larger among high than low sensation seeking participants.

Connecting brain responsivity and real-world risk taking: Strengths and limitations of current methodological approaches

In line with the goal of limiting health risk behaviors in adolescence, a growing literature investigates whether individual differences in functional brain responses can be related to vulnerability to engage in risky decision-making. We review this body of work, investigate when and in what way findings converge, and provide best practice recommendations. We identified 23 studies that examined individual differences in brain responsivity and adolescent risk taking. Findings varied widely in terms of the neural regions identified as relating to risky behavior. This heterogeneity is likely due to the abundance of approaches used to assess risk taking, and to the disparity of fMRI tasks. Indeed, brain-behavior correlations were typically found in regions showing a main effect of task. However, results from a test of publication bias suggested that region of interest approaches lacked evidential value. The findings suggest that neural factors differentiating riskier teens are not localized to a single region. Therefore, approaches that utilize data from the entire brain, particularly in predictive analyses, may yield more reliable and applicable results. We discuss several decision points that researchers should consider when designing a study, and emphasize the importance of precise research questions that move beyond a general desire to address adolescent risk taking.

The ABCD study of neurodevelopment: Identifying neurocircuit targets for prevention and treatment of adolescent substance abuse

Substance use disorders (SUD) can be considered developmental disorders in light of their frequent origins in substance initiation during adolescence. Cross-sectional functional magnetic resonance imaging (fMRI) studies of adolescent substance users or adolescents with SUD have indicated aberrations in brain structures or circuits implicated in motivation, self-control, and mood-regulation. However, attributing these differences to the neurotoxicological effects of chronic substance use has been problematic in that these circuits are also aberrant in at-risk children, such as those with prenatal substance exposure, externalizing disorders (such as conduct disorder), or prodromal internalizing disorders such as depression. To better isolate the effects of substance exposure on the adolescent brain, the newly-launched Adolescent Brain Cognitive Development (ABCD) study, funded by the National Institutes of Health, will follow the neurodevelopmental trajectories of over 11,000 American 9/10-year-olds for 10 years, into emerging adulthood. This study will provide a rich open-access dataset on longitudinal interactions of neurodevelopment, environmental exposures, and childhood psychopathology that confer addiction risk. The ABCD twin study will further clarify genetic versus experiential influences (e.g., substance use) on neurodevelopmental and psychosocial outcomes. Neurocircuitry thought to regulate mood and behavior has been directly normalized by administration of psychoactive medications and by cognitive therapies in adults. Because of this, we contend that ABCD project data will be a crucial resource for prevention and treatment of SUD in adolescence because its cutting-edge neuroimaging and childhood assessments hold potential for discovery of additional targetable brain differences earlier in development that are prognostic of (or aberrant in) SUD. The ABCD sample size will also have the power to illuminate how sex differences, environmental interactions and other individual differences interact with neurodevelopment to inform treatment in different groups of adolescents.

Striatal dopaminergic reward response relates to age of first drunkenness and feedback response in at-risk youth

Dopamine receptor concentrations, primarily in the striatum, are hypothesized to contribute to a developmental imbalance between subcortical and prefrontal control systems in emerging adulthood potentially biasing motivation and increasing risky behaviors. Positron emission tomography studies have found significant reductions in striatal dopamine D2 receptors, and blunted amphetamine-induced dopamine release, in substance users compared with healthy controls. Extant literature is limited and inconsistent concerning vulnerability associated with having a family history of substance abuse (FH+). Some studies have reported familial liability associated with higher dopamine receptor levels, reduced dopamine response to stimulant challenges and decreased response to oral alcohol. However, other reports have failed to find group differences based on family history. We explored the interaction of familial liability and behavioral risk with multi-modal molecular and neural imaging of the dopaminergic system. Forty-four young adult male subjects performed monetary incentive delay tasks during both [¹¹ C]raclopride positron emission tomography and functional magnetic resonance imaging scans. FH+ subjects were identified as low (n = 24) or high risk (n = 9) based on early initiation of drunkenness. FH+ high-risk subjects exhibited heightened striatal dopamine response to monetary reward but did not differ in neural activations compared with FH+ low risk subjects and controls with no familial loading (n = 11). Across all subjects, a negative relationship was found between dopamine release and age of first drunkenness and a positive relationship with neural response to reward receipt. These results suggest that in at-risk individuals, higher dopamine transmission associated with monetary reward may represent a particularly useful neurobiological phenotype.

Modulation of reward-related neural activation on sensation seeking across development

Sensation seeking is a personality construct associated with an increased propensity for engaging in risk-taking. Associations with deleterious outcomes ranging from mental health impairments to increased mortality rates highlight important public health concerns related to this construct. Although some have suggested that increased neural responsivity to reward within the ventral striatum (e.g., nucleus accumbens) may drive sensation seeking behaviors, few studies have examined the neural mechanisms associated with stable individual differences in sensation seeking across development. To address this issue, the current study used functional magnetic resonance imaging to examine the association between neural responding to reward and stable patterns of sensation seeking across a three-year follow-up period among healthy adolescents and young adults (N = 139). Results indicated that during early adolescence (~ages 10-12), increased reactivity to reward within the nucleus accumbens (NAcc) was associated with lower levels of sensation seeking across a three-year follow-up. In middle adolescence (~ages 12-16), there was no evidence of a relationship between NAcc reactivity and sensation seeking. However, during the transition from late adolescence into adulthood (~ages 17-25), heightened reward-related reactivity in the NAcc was linked to increased sensation seeking. Findings suggest that the neural mechanisms underlying individual differences in trait-like levels of sensation seeking change from early to late adolescence.

Adolescence and Drug Use Vulnerability: Findings from Neuroimaging

Adolescence is a period of vulnerability for developing substance use disorder. Recent neuropsychological and neuroimaging studies have elucidated underlying neural vulnerabilities that contribute to initiation of substance use during adolescence. Findings suggest poorer performance on tasks of inhibition and working memory, smaller brain volumes in reward and cognitive control regions, less brain activation during executive functioning tasks, and heightened reward responsivity are predictive of youth initiating substance use during adolescence. In youth who are family history positive (FHP) for substance use disorder, poorer executive functioning, smaller volume of limbic brain regions (e.g., amygdala), sex-specific patterns of hippocampal volume, and a positive association between nucleus accumbens volume and family history density have been reported. Further, reduced white matter integrity, altered brain response during inhibitory control, including both greater and less frontal lobe response, blunted emotional processing, and weaker neural connectivity have also been found in FHP youth. Thus, there is significant overlap among the neural precursors shown to be predictive of alcohol and substance use initiation during adolescence and those that distinguish FHP from youth without a family history of substance use disorder, suggesting common targets for prevention and intervention. Understanding these predictive factors helps identify at-risk youth for prevention efforts, as well as create interventions targeting cognitive weaknesses or brain regions involved in substance use initiation.

Willing to wait: Elevated reward-processing EEG activity associated with a greater preference for larger-but-delayed rewards

While almost everyone discounts the value of future rewards over immediate rewards, people differ in their so-called delay-discounting. One of the several factors that may explain individual differences in delay-discounting is reward-processing. To study individual-differences in reward-processing, however, one needs to consider the heterogeneity of neural-activity at each reward-processing stage. Here using EEG, we separated reward-related neural activity into distinct reward-anticipation and reward-outcome stages using time-frequency characteristics. Thirty-seven individuals first completed a behavioral delay-discounting task. Then reward-processing EEG activity was assessed using a separate reward-learning task, called a reward time-estimation task. During this EEG task, participants were instructed to estimate time duration and were provided performance feedback on a trial-by-trial basis. Participants received monetary-reward for accurate-performance on Reward trials, but not on No-Reward trials. Reward trials, relative to No-Reward trials, enhanced EEG activity during both reward-anticipation (including, cued-locked delta power during cue-evaluation and pre-feedback alpha suppression during feedback-anticipation) and reward-outcome (including, feedback-locked delta, theta and beta power) stages. Moreover, all of these EEG indices correlated with behavioral performance in the time-estimation task, suggesting their essential roles in learning and adjusting performance to maximize winnings in a reward-learning situation. Importantly, enhanced EEG power during Reward trials, as reflected by stronger 1) pre-feedback alpha suppression, 2) feedback-locked theta and 3) feedback-locked beta, was associated with a greater preference for larger-but-delayed rewards in a separate, behavioral delay-discounting task. Results highlight the association between a stronger preference toward larger-but-delayed rewards and enhanced reward-processing. Moreover, our reward-processing EEG indices detail the specific stages of reward-processing where these associations occur.

Annual Research Review: Neural contributions to risk-taking in adolescence--developmental changes and individual differences

BACKGROUND

Risk-taking, which involves voluntary choices for behaviors where outcomes remain uncertain, undergoes considerable developmental changes during childhood, adolescence, and early adulthood. In addition, risk-taking is thought to be a key element of many externalizing disorders, such as ADHD, delinquency, conduct disorder, and substance abuse. In this review, we will discuss the potential adaptive and nonadaptive properties of risk-taking in childhood and adolescence.

FINDINGS

We propose that the changes in brain architecture and function are a crucial element underlying these developmental trajectories. We first identify how subcortical and cortical interactions are important for understanding risk-taking behavior in adults. Next, we show how developmental changes in this network underlie changes in risk-taking behavior. Finally, we explore how these differences can be important for understanding externalizing behavioral disorders in childhood and adolescence.

CONCLUSIONS

We conclude that longitudinal studies are of crucial importance for understanding these developmental trajectories, and many of these studies are currently underway.

Testing the Relations Among Family Disorganization, Delay Discounting, and Adolescent Alcohol Use: A Genetically Informed Study

BACKGROUND

Delay discounting is a potential etiological factor in adolescents' alcohol use, making it important to understand its antecedents. Family disorganization might contribute to delay discounting, but few studies have tested this relation. Moreover, because delay discounting is heritable, the effects of family disorganization on delay discounting might be moderated by adolescents' genetic risk for delay discounting. Thus, the current study examined the role of family disorganization, in interaction with genetic risk, in predicting adolescents' delay discounting and subsequent alcohol use.

METHODS

Adolescents participated in 4 waves of data collection. Adolescents self-reported their family disorganization at T1, completed a delay discounting questionnaire at T3, and self-reported their alcohol use both at T2 (covariate) and T4 (outcome). Using results from an independent sample, we created a polygenic risk score consisting of dopaminergic genes to index genetic risk for delay discounting.

RESULTS

Greater family disorganization predicted adolescents' greater delay discounting, but only for adolescents with low levels of genetic risk for delay discounting. Adolescents with high and mean levels of genetic risk for delay discounting showed elevated delay discounting regardless of their family's disorganization. Greater delay discounting prospectively predicted adolescents' greater alcohol use. Finally, the effects of family disorganization on adolescents' alcohol use were mediated through delay discounting, but only for adolescents with low levels of genetic risk.

CONCLUSIONS

Results suggest multiple pathways to delay discounting. Although there are genetically influenced pathways to delay discounting, family disorganization might represent an environmental pathway to delay discounting (and subsequent alcohol use) for a subset of adolescents at low genetic risk. These findings reinforce the utility of family interventions for reducing adolescents' delay discounting and alcohol use, at least for a subgroup of adolescents. Because higher family organization did not buffer against delay discounting among adolescents with high genetic risk, future research should explore other early environmental influences that could protect these high-risk adolescents from developing these risky behaviors.