Cortical activation deficits during facial emotion processing in youth at high risk for the development of substance use disorders

Neural activations during cognitive and affective theory of mind processing in healthy adults with a family history of alcohol use disorder

BACKGROUND

Social cognition impairments are a common feature of alcohol use disorders (AUD). However, it remains unclear whether these impairments are solely the consequence of chronic alcohol consumption or whether they could be a marker of vulnerability.

METHODS

The present study implemented a family history approach to address this question for a key process of social cognition: theory of mind (ToM). Thirty healthy adults with a family history of AUD (FH+) and 30 healthy adults with a negative family history of AUD (FH-), matched for age, sex, and education level, underwent an fMRI cartoon-vignette paradigm assessing cognitive and affective ToM. Participants also completed questionnaires evaluating anxiety, depressive symptoms, childhood trauma, and alexithymia.

RESULTS

Results indicated that FH+ individuals differed from FH- individuals on affective but not cognitive ToM processing, at both the behavioral and neural levels. At the behavioral level, the FH+ group had lower response accuracy for affective ToM compared with the FH- group. At the neural level, the FH+ group had higher brain activations in the left insula and inferior frontal cortex during affective ToM processing. These activations remained significant when controlling for depressive symptoms, anxiety, and childhood trauma.

CONCLUSIONS

These findings highlight difficulties during affective ToM processing among first-degree relatives of AUD patients, supporting the idea that some of the impairments exhibited by these patients may already be present before the onset of AUD and may be considered a marker of vulnerability.

Parental Deprivation- and Threat-Based Factors Associated with Youth Emotion-Based Neurocircuitry and Externalizing Behavior: A Systematic Review

Parental factors, including negative parenting practices (e.g., family conflict, low monitoring), parental depression, and parental substance use, are associated with externalizing behaviors among youth. However, the ways in which these parental factors are associated with youth brain function and consequent externalizing behavior has been less studied. Both the dimensional and stress acceleration models provide frameworks for understanding how parental factors may be associated with frontolimbic and frontoparietal networks implicated in emotional attention and regulation processes. The current review builds upon this work by examining how deprivation- and threat-based parental factors are associated with youth neurocircuitry involved in emotional functioning and externalizing behaviors. A systematic review using PRISMA guidelines was completed and included five studies assessing parenting behaviors, six studies assessing parental depressive symptoms and/or diagnosis, and 12 studies assessing parental history of substance use. Synthesis of reviewed studies discusses support for the dimensional and stress acceleration models within the context of deprivation and threat. Further, a limited number of studies tested (i.e., six studies) and supported (i.e., three studies) youth neural structure and function as a mediator of the association between parental factors and youth externalizing behavior. Specific recommendations for future work include more deliberate planning related to sample composition, improved clarity related to parental constructs, consistency in methodology, and longitudinal study design in order to better understand associations between contextual parental influences and youth neural and behavioral functioning.

Adaptor protein complex 2 in the orbitofrontal cortex predicts alcohol use disorder

Alcohol use disorder (AUD) is a life-threatening disease characterized by compulsive drinking, cognitive deficits, and social impairment that continue despite negative consequences. The inability of individuals with AUD to regulate drinking may involve functional deficits in cortical areas that normally balance actions that have aspects of both reward and risk. Among these, the orbitofrontal cortex (OFC) is critically involved in goal-directed behavior and is thought to maintain a representation of reward value that guides decision making. In the present study, we analyzed post-mortem OFC brain samples collected from age- and sex-matched control subjects and those with AUD using proteomics, bioinformatics, machine learning, and reverse genetics approaches. Of the 4,500+ total unique proteins identified in the proteomics screen, there were 47 proteins that differed significantly by sex that were enriched in processes regulating extracellular matrix and axonal structure. Gene ontology enrichment analysis revealed that proteins differentially expressed in AUD cases were involved in synaptic and mitochondrial function, as well as transmembrane transporter activity. Alcohol-sensitive OFC proteins also mapped to abnormal social behaviors and social interactions. Machine learning analysis of the post-mortem OFC proteome revealed dysregulation of presynaptic (e.g., AP2A1) and mitochondrial proteins that predicted the occurrence and severity of AUD. Using a reverse genetics approach to validate a target protein, we found that prefrontal Ap2a1 expression significantly correlated with voluntary alcohol drinking in male and female genetically diverse mouse strains. Moreover, recombinant inbred strains that inherited the C57BL/6J allele at the Ap2a1 interval consumed higher amounts of alcohol than those that inherited the DBA/2J allele. Together, these findings highlight the impact of excessive alcohol consumption on the human OFC proteome and identify important cross-species cortical mechanisms and proteins that control drinking in individuals with AUD.

Adaptor protein complex 2 in the orbitofrontal cortex predicts alcohol use disorder

Alcohol use disorder (AUD) is a life-threatening disease characterized by compulsive drinking, cognitive deficits, and social impairment that continue despite negative consequences. The inability of individuals with AUD to regulate drinking may involve functional deficits in cortical areas that normally balance actions that have aspects of both reward and risk. Among these, the orbitofrontal cortex (OFC) is critically involved in goal-directed behavior and is thought to maintain a representation of reward value that guides decision making. In the present study, we analyzed post-mortem OFC brain samples collected from age- and sex-matched control subjects and those with AUD using proteomics, bioinformatics, machine learning, and reverse genetics approaches. Of the 4,500+ total unique proteins identified in the proteomics screen, there were 47 proteins that differed significantly by sex that were enriched in processes regulating extracellular matrix and axonal structure. Gene ontology enrichment analysis revealed that proteins differentially expressed in AUD cases were involved in synaptic and mitochondrial function, as well as transmembrane transporter activity. Alcohol-sensitive OFC proteins also mapped to abnormal social behaviors and social interactions. Machine learning analysis of the post-mortem OFC proteome revealed dysregulation of presynaptic (e.g., AP2A1) and mitochondrial proteins that predicted the occurrence and severity of AUD. Using a reverse genetics approach to validate a target protein, we found that prefrontal Ap2a1 expression significantly correlated with voluntary alcohol drinking in male and female genetically diverse mouse strains. Moreover, recombinant inbred strains that inherited the C57BL/6J allele at the Ap2a1 interval consumed higher amounts of alcohol than those that inherited the DBA/2J allele. Together, these findings highlight the impact of excessive alcohol consumption on the human OFC proteome and identify important cross-species cortical mechanisms and proteins that control drinking in individuals with AUD.

Impulsivity as a Predictor of Early Dating Initiation in 11-12-Year-Old Youth

As early initiation of dating behaviors is associated with risky sexual behaviors (e.g., higher number of sexual partners, sex with strangers), the current study examined determinants of early dating behaviors, focusing on impulsivity. Participants were 11-12-year-old boys (n = 109) and girls (n = 61) recruited from a psychiatric clinic and ads targeted to the general public. Ordered logistic regression models were used to examine the association between each facet of impulsivity (negative urgency, positive urgency, lack of premeditation, lack of perseverance, and sensation seeking) and dating behaviors. Youth with higher sensation seeking and negative urgency was more likely to initiate dating behaviors at early ages compared to those with lower scores on those measures. Further, we found that female gender and higher parental education were associated with lower risk of initiating dating behaviors at early age. Advanced pubertal development was associated with higher risk for early dating. Our findings can inform prevention efforts, identifying sensation seeking and negative urgency as predictors of youths' early engagement in dating behaviors, which can be a precursor of early sexual debut and risky sexual behaviors.

Fear of missing out (FOMO) associates with reduced cortical thickness in core regions of the posterior default mode network and higher levels of problematic smartphone and social media use

BACKGROUND AND AIMS

Fear of missing out (FOMO) promotes the desire or urge to stay continuously connected with a social reference group and updated on their activities, which may result in escalating and potentially addictive smartphone and social media use. The present study aimed to determine whether the neurobiological basis of FOMO encompasses core regions of the reward circuitry or social brain, and associations with levels of problematic smartphone or social media use.

METHODS

We capitalized on a dimensional neuroimaging approach to examine cortical thickness and subcortical volume associations in a sample of healthy young individuals (n = 167). Meta-analytic network and behavioral decoding analyses were employed to further characterize the identified regions.

RESULTS

Higher levels of FOMO associated with lower cortical thickness in the right precuneus. In contrast, no associations between FOMO and variations in striatal morphology were observed. Meta-analytic decoding revealed that the identified precuneus region exhibited a strong functional interaction with the default mode network (DMN) engaged in social cognitive and self-referential domains.

DISCUSSION AND CONCLUSIONS

Together the present findings suggest that individual variations in FOMO are associated with the brain structural architecture of the right precuneus, a core hub within a large-scale functional network resembling the DMN and involved in social and self-referential processes. FOMO may promote escalating social media and smartphone use via social and self-referential processes rather than reward-related processes per se.

Low versus high level of response to alcohol affects amygdala functional connectivity during processing of emotional stimuli

BACKGROUND

Low levels of response (low LR) to alcohol predict heavy drinking and alcohol problems. Functional magnetic resonance imaging (fMRI) studies of emotion processing have shown that low LR individuals exhibit lower activation in task-related brain regions following both placebo and alcohol administration, but these studies did not examine functional brain networks that might contribute to the phenomena. The current study expands upon the earlier results by evaluating whether functional connectivity differences between the amygdala and other brain regions modulated by emotional face processing are associated with LR. Based on prior findings, we hypothesized that low LR is related to lower functional connectivity in fronto-amygdalar functional circuits, which underlie the processing of emotional stimuli.

METHODS

Secondary analyses were conducted on data from a double-blind, placebo-controlled, within-subjects, cross-over study in 108 18-to-25-year-old low and high LR sex-matched pairs without alcohol use disorder at baseline. Participants performed modified emotional faces processing tasks after receiving placebo or approximately 0.7 ml/kg of ethanol. Psychophysiological interaction analyses examined functional connectivity between left and right amygdalae and related brain circuits using LR-by-alcohol general linear models. The data included 54 sex-matched pairs with 216 fMRI scans comprising alcohol and placebo conditions.

RESULTS

Compared with individuals with high LR, low LR subjects demonstrated lower functional connectivity between the amygdala and the frontal lobes, insula, and parietal regions, while processing angry and happy faces. Interactions showed lower connectivity following alcohol in low LR and higher connectivity in high LR groups.

CONCLUSIONS

Low LR individuals demonstrated lower functional connectivity in response both to placebo and a modest dose of ethanol. Attenuated connectivity among low LR individuals when processing emotional faces may contribute to an impaired ability to recognize alcohol intoxication in social situations and to appraise angry and happy emotions irrespective of whether alcohol is consumed.

Systematic review and meta-analysis of socio-cognitive and socio-affective processes association with adolescent substance use

BACKGROUND

Social impairments are important features of a substance use disorder diagnosis; and recent models suggest early impairments in socio-cognitive and -affective processes may predict future use. However, no systematic reviews are available on this topic.

METHODS

We conducted a systematic review and meta-analyses exploring the association between social-cognitive and -affective processes (empathy, callous-unemotional (CU) traits, theory of mind, and social cognition) and substance use frequency (alcohol, cannabis, general drug use). We examined moderating effects of study design, gender, age, and weather conduct problems were controlled for. We also review brain studies related to social cognition and substance use disorder (SUD) risk.

RESULTS

Systematic review suggested a negative association for positively valenced constructs with substance use but mixed results on the negatively valenced construct CU traits. Meta-analyses revealed moderate positive association between CU traits with alcohol and general drug use but no significance with cannabis use. Moderate effect sizes were found for CU traits in youth predicting severity of substance use by late adolescence and significantly accounted for variance independently of conduct problems. Significant moderators included gender proportions, sample type, and age. Neuroimaging meta-analysis indicated 10 coordinates that were different in youth at a high risk/with SUD compared to controls. Three of these coordinates associate with theory of mind and social cognition.

CONCLUSION

Socio-cognitive and -affective constructs demonstrate an association with current and future substance use, and neural differences are present when performing social cognitive tasks in regions with strongest associations with theory of mind and social cognition.

Meta-analysis and review of functional neuroimaging differences underlying adolescent vulnerability to substance use

Adolescence is increasingly viewed as a sensitive period in the development of substance use disorders (SUDs). Neurodevelopmental 'dual-risk' theories suggest adolescent vulnerability to problematic substance use is driven by an overactive reward drive mediated by the striatum, and poor cognitive control mediated by the prefrontal cortex. To this end, there has been a growing number of neuroimaging studies examining cognitive and affective neural systems during adolescence for markers of vulnerability to problematic substance use. Here, we perform a coordinate-based meta-analysis on this emerging literature. Twenty-two task-based voxelwise fMRI studies with activation differences associated with substance use vulnerability, representative of approximately 1092 subjects, were identified through a systematic literature search (PubMed, Scopus) and coordinates of activation differences (N ​= ​190) were extracted. Adolescents were defined as 'at-risk' for problematic substance use based on a family history of SUD or through prospective prediction of substance use initiation or escalation. Multilevel kernel density analysis was used to identify the most consistent brain regions associated with adolescent substance use vulnerability. Across the included studies, substance use vulnerability was most reliably associated with activation differences in the striatum, where at-risk adolescents had hyper-activation in the dorsal subdivision (putamen). Follow-up analyses suggested striatal differences were driven by tasks sharing a motivational and/or reward component (e.g., monetary incentive) and common across subgroups of substance use risk (family history and prospective prediction studies). Analyses examining the role of psychiatric comorbidity revealed striatal activation differences were significantly more common in samples whose definition of substance use risk included cooccurring externalizing psychopathology. Furthermore, substance use risk meta-analytic results were no longer significant when excluding these studies, although this may reflect limitations in statistical power. No significant activation differences were observed in prefrontal cortex in any analysis. These results suggest striatal dysfunction, rather than prefrontal, may be a more primary neural feature of adolescent vulnerability to problematic substance use, possibly through a dimension of individual variability shared with externalizing psychopathology. However, our systematic literature search confirms this is still an emerging field. More studies, increased data sharing, and further quantitative integration are necessary for a comprehensive understanding of the neuroimaging markers of adolescent substance use risk.

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).

Alcohol use disorder and cannabis use disorder symptomatology in adolescents are differentially related to dysfunction in brain regions supporting face processing

Despite extensive behavioral evidence of impairments in face processing and expression recognition in adults with alcohol or cannabis use disorders (AUD/CUD), neuroimaging findings have been inconsistent. Moreover, relatively little work has examined the relationship of AUD or CUD symptoms with face or expression processing within adolescents. Given the high prevalence of alcohol and cannabis use during adolescence, understanding how these usage behaviors interact with neural mechanisms supporting face and expression processing could have important implications for youth social and emotional functioning. In this study, adolescents (N = 104) responded to morphed fearful and happy expressions during fMRI and their level of AUD and/or CUD symptoms were related to the BOLD response data. We found that AUD and CUD symptom severity were both negatively related to responses to faces generally. However, whereas this relationship was shown for AUD within ventromedial prefrontal cortex and lingual gyrus, it was shown for CUD within rostromedial prefrontal cortex including anterior cingulate cortex. Additionally, AUD symptom levels were associated with differential responses within medial temporal pole and inferior parietal lobule as a function of expression. These results have potential implications for understanding the social and emotional functioning of adolescents with AUD and CUD symptoms.

Emotional processing and social cognition in alcohol use disorder

OBJECTIVE

To review deficits in emotional processing and social cognition potentially contributing to the dysfunctional emotion regulation and difficulties with interpersonal relationships observed in individuals with alcohol use disorder (AUD) and to provide directions for future research.

METHOD

First is presented a review of emotional and social-cognitive impairments in recently detoxified AUD individuals that include alexithymia, difficulties in decoding others' emotions, and reduced theory of mind and empathy skills. Social cognition disorders in AUD pose different issues discussed, such as whether (1) these deficits are consequences of excessive alcohol consumption or premorbid risk factors for addiction, (2) emotional and social impairments impede positive treatment outcome, (3) recovery of social abilities is possible with sustained abstinence, and (4) AUD patients are unaware of their emotional and social dysfunctions. Finally, current knowledge on structural and functional brain correlates of these deficits in AUD are reviewed.

RESULTS

Emotional and social-cognitive functions affected in AUD can potentially compromise efforts to initiate and maintain abstinence by hampering efficacy of clinical treatment. Such dysfunction can obstruct efforts to enable or reinstate higher-order abilities such as emotional self-regulation, motivation to change, success in interpersonal/social interactions, and emotional insight and awareness of social dysfunctions (i.e., accurate metacognition).

CONCLUSIONS

The present review highlights the need to account for emotional processing and social cognition in the evaluation and rehabilitation of alcohol-related neurocognitive disorders and to consider psychotherapeutic treatment involving remediation of emotional and social skills as implemented in psychiatric and neurological disorders. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

DRD2 methylation and regional grey matter volumes in young adult offspring from families at ultra-high risk for alcohol dependence

Dopaminergic alteration is a prominent feature in those with AD and may influence brain development in those with a family history of AD. MRI scans (3T) from 43 HR offspring (27.4 ± 3.6 years) and 45 controls (24.5 ± 4.1 years) provided whole brain (WB) and region of interest (ROI) analyses. The VBM8 toolbox was used for WB analysis (threshold p < 0.005; cluster = 100 voxels); the MarsBaR ROI toolbox provided region of interest data. Pyrosequencing of CpG sites within the DRD2 gene was performed. DRD2 methylation was significantly increased in association with familial high-risk status. Significant familial risk group differences were seen with HR individuals showing reduced volume of the Left Inferior Temporal, Left Fusiform and Left Insula regions relative to LR controls. These regions have previously been linked to social cognition. DRD2 methylation was negatively related to grey matter volumes in these regions. Because these regions, have been previously linked to facial affect perception and social cognition, lesser grey matter volumes in individuals at high-risk for developing AD suggests that neural underpinnings of social cognitive impairment may be a premorbid risk factors for AD.

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.

Chronic Stress in Adolescents and Its Neurobiological and Psychopathological Consequences: An RDoC Perspective

The Research Domain Criteria (RDoC) initiative provides a strategy for classifying psychopathology based on behavioral dimensions and neurobiological measures. Neurodevelopment is an orthogonal dimension in the current RDoC framework; however, it has not yet been fully incorporated into the RDoC approach. A combination of both a neurodevelopmental and RDoC approach offers a multidimensional perspective for understanding the emergence of psychopathology during development. Environmental influence (e.g., stress) has a profound impact on the risk for development of psychiatric illnesses. It has been shown that chronic stress interacts with the developing brain, producing significant changes in neural circuits that eventually increase the susceptibility for development of psychiatric disorders. This review highlights effects of chronic stress on the adolescent brain, as adolescence is a period characterized by a combination of significant brain alterations, high levels of stress, and emergence of psychopathology. The literature synthesized in this review suggests that chronic stress-induced changes in neurobiology and behavioral constructs underlie the shared vulnerability across a number of disorders in adolescence. The review particularly focuses on depression and substance use disorders; however, a similar argument can also be made for other psychopathologies, including anxiety disorders. The summarized findings underscore the need for a framework to integrate neurobiological findings from disparate psychiatric disorders and to target transdiagnostic mechanisms across disorders.

Global white matter microstructural abnormalities associated with addiction liability score in drug naïve youth

Abnormalities in brain white matter (WM) structure have been reported in youths having a family history of substance use disorders (SUDs). It was hypothesized that these abnormalities constitute features of the liability for SUDs transmitted across generations. The association between severity of intergenerational risk for SUD, measured by the Transmissible Liability Index (TLI), and white matter microstructure was examined. Diffusion tensor imaging (DTI) measured WM microstructure in forty-four drug-naïve 10-14 year-olds (N = 19 with parental SUD). Metrics of WM microstructure (i.e., fractional anisotropy, radial diffusivity, mean diffusivity and axial diffusivity) were quantified across the whole brain and in four tracts of interest: anterior corona radiata, superior and inferior longitudinal fasciculi and superior fronto-occipital fasciculi. The TLI was completed by the youths, their parents and, when available, their teachers. The relationship between WM structure and TLI score across the entire group was evaluated using linear multiple regression and between group comparisons were also examined. Fractional anisotropy and radial diffusivity in multiple tracts across the brain were significantly associated with TLI scores. Confirming and extending prior research, the findings indicate that global atypicality in WM tracts was linearly related to liability for eventual SUD development in drug naïve youths.

Negative urgency and emotion regulation predict positive smoking expectancies in non-smoking youth

INTRODUCTION

The purpose of the study was to better understand early risk for positive smoking expectancies, which have been shown to be consistent predictors of smoking initiation among youth. Two affect-based risk factors-negative urgency and emotion dysregulation-associated with smoking behaviors among youth, were examined for unique and interactive effects on positive smoking expectancies among substance-naïve youth.

METHODS

Participants were 61 10-14-year-old children with virtually no drug use (less than 5 substance use incidents across the lifetime), who were drawn from the community.

RESULTS

Both negative urgency and emotion dysregulation were significantly associated with positive social facilitation smoking expectancies. Further, negative urgency was significantly related to positive social facilitation smoking expectancies at higher levels of emotion dysregulation (b=.09, p=.001).

CONCLUSION

The findings provide evidence that both emotion dysregulation and negative urgency are positively associated with positive social-related smoking expectancies among a sample of 10-14-year-olds. Children who are emotionally dysregulated and who act rashly in response to negative emotions appear more likely to endorse beliefs regarding the socially enhancing effects of smoking, suggesting that these youth may be at high risk for smoking initiation.

Toward early estimation and treatment of addiction vulnerability: radial arm maze and N-acetyl cysteine before cocaine sensitization or nicotine self-administration in neonatal ventral hippocampal lesion rats

RATIONAL

Prefrontal cortical (PFC)-hippocampal-striatal circuits, interconnected via glutamatergic signaling, are dysfunctional in mental illnesses that involve addiction vulnerability.

OBJECTIVES

In healthy and neurodevelopmentally altered rats, we examined how Radial Arm Maze (RAM) performance estimates addiction vulnerability, and how starting a glutamatergic modulating agent, N-acetyl cysteine (NAC) in adolescence alters adult mental illness and/or addiction phenotypes.

METHODS

Rats with neonatal ventral hippocampal lesions (NVHL) vs. SHAM-operated controls were randomized to NAC vs. saline in adolescence followed by cognitive testing (RAM) in early adulthood and then cocaine behavioral sensitization (experiment 1; n = 80) or nicotine self-administration (experiment 2; n = 12).

RESULTS

In experiment 1, NVHL rats showed over-consumption of food (Froot-Loops (FL)) baiting the RAM with poor working memory (low-arm entries to repeat (ETR)), producing an elevated FL to ETR ratio ("FLETR"; p < 0.001). FLETR was the best linear estimator (compared to FL or ETR) of magnitude of long-term cocaine sensitization (R ² = 0.14, p < 0.001). NAC treatment did not alter FL, ETR, FLETR, or cocaine sensitization. In experiment 2, FLETR also significantly and uniquely correlated with subsequent drug seeking during nicotine-induced reinstatement after extinction of nicotine self-administration (R ² = 0.47, p < 0.01). NAC did not alter RAM performance, but significantly reversed NVHL-induced increases in nicotine seeking during extinction and reinstatement.

CONCLUSIONS

These findings demonstrate the utility of animal models of mental illness with addiction vulnerability for developing novel diagnostic measures of PFC-hippocampal-striatal circuit dysfunction that may reflect addiction risk. Such tests may direct pharmacological treatments prior to adulthood and addictive drug exposure, to prevent or treat adult addictions.

Neural activation during risky decision-making in youth at high risk for substance use disorders

Risky decision-making, particularly in the context of reward-seeking behavior, is strongly associated with the presence of substance use disorders (SUDs). However, there has been little research on the neural substrates underlying reward-related decision-making in drug-naïve youth who are at elevated risk for SUDs. Participants comprised 23 high-risk (HR) youth with a well-established SUD risk phenotype and 27 low-risk healthy comparison (HC) youth, aged 10-14. Participants completed the balloon analog risk task (BART), a task designed to examine risky decision-making, during functional magnetic resonance imaging. The HR group had faster reaction times, but otherwise showed no behavioral differences from the HC group. HR youth experienced greater activation when processing outcome, as the chances of balloon explosion increased, relative to HC youth, in ventromedial prefrontal cortex (vmPFC). As explosion probability increased, group-by-condition interactions in the ventral striatum/anterior cingulate and the anterior insula showed increasing activation in HR youth, specifically on trials when explosions occurred. Thus, atypical activation increased with increasing risk of negative outcome (i.e., balloon explosion) in a cortico-striatal network in the HR group. These findings identify candidate neurobiological markers of addiction risk in youth at high familial and phenotypic risk for SUDs.

Psychological and Neurobiological Precursors of Alcohol Use Disorders in High Risk Youth

It has long been known that Alcohol Use Disorders (AUDs) run in families with substantial heritability. Determining the specific genetic underpinnings of these disorders has been challenging because of the clinical heterogeneity and variable expression across the lifespan. The search for endophenotypic biological variation associated with the AUD and related substance use disorder (SUD) phenotypes is based on the belief that an endophenotype is more proximal to the causative gene. Identification of genes conferring increased susceptibility has important implications for treatment through the potential development of medications that target specific genetic pathways. High risk family designs that contrast offspring with and without a familial/genetic background have provided valuable insights into the psychological characteristics (executive control, affective regulation, decision making and social cognition) that differentiate such individuals. The current chapter will review these with a focus on brain morphology of specific regions, the coordinated activity of neural networks, and developmental trajectories of electrophysiological activity.

In the face of threat: neural and endocrine correlates of impaired facial emotion recognition in cocaine dependence

The ability to recognize facial expressions of emotion in others is a cornerstone of human interaction. Selective impairments in the recognition of facial expressions of fear have frequently been reported in chronic cocaine users, but the nature of these impairments remains poorly understood. We used the multivariate method of partial least squares and structural magnetic resonance imaging to identify gray matter brain networks that underlie facial affect processing in both cocaine-dependent (n = 29) and healthy male volunteers (n = 29). We hypothesized that disruptions in neuroendocrine function in cocaine-dependent individuals would explain their impairments in fear recognition by modulating the relationship with the underlying gray matter networks. We found that cocaine-dependent individuals not only exhibited significant impairments in the recognition of fear, but also for facial expressions of anger. Although recognition accuracy of threatening expressions co-varied in all participants with distinctive gray matter networks implicated in fear and anger processing, in cocaine users it was less well predicted by these networks than in controls. The weaker brain-behavior relationships for threat processing were also mediated by distinctly different factors. Fear recognition impairments were influenced by variations in intelligence levels, whereas anger recognition impairments were associated with comorbid opiate dependence and related reduction in testosterone levels. We also observed an inverse relationship between testosterone levels and the duration of crack and opiate use. Our data provide novel insight into the neurobiological basis of abnormal threat processing in cocaine dependence, which may shed light on new opportunities facilitating the psychosocial integration of these patients.

Adolescent alcohol exposure reduces behavioral flexibility, promotes disinhibition, and increases resistance to extinction of ethanol self-administration in adulthood

The prefrontal cortex (PFC) is a brain region that is critically involved in cognitive function and inhibitory control of behavior, and adolescence represents an important period of continued PFC development that parallels the maturation of these functions. Evidence suggests that this period of continued development of the PFC may render it especially vulnerable to environmental insults that impact PFC function in adulthood. Experimentation with alcohol typically begins during adolescence when binge-like consumption of large quantities is common. In the present study, we investigated the effects of repeated cycles of adolescent intermittent ethanol (AIE) exposure (postnatal days 28-42) by vapor inhalation on different aspects of executive functioning in the adult rat. In an operant set-shifting task, AIE-exposed rats exhibited deficits in their ability to shift their response strategy when the rules of the task changed, indicating reduced behavioral flexibility. There were no differences in progressive ratio response for the reinforcer suggesting that AIE did not alter reinforcer motivation. Examination of performance on the elevated plus maze under conditions designed to minimize stress revealed that AIE exposure enhanced the number of entries into the open arms, which may reflect either reduced anxiety and/or disinhibition of exploratory-like behavior. In rats that trained to self-administer ethanol in an operant paradigm, AIE increased resistance to extinction of ethanol-seeking behavior. This resistance to extinction was reversed by positive allosteric modulation of mGluR5 during extinction training, an effect that is thought to reflect promotion of extinction learning mechanisms within the medial PFC. Consistent with this, CDPPB was also observed to reverse the deficits in behavioral flexibility. Finally, diffusion tensor imaging with multivariate analysis of 32 brain areas revealed that while there were no differences in the total brain volume, the volume of a subgroup of regions (hippocampus, thalamus, dorsal striatum, neocortex, and hypothalamus) were significantly different in AIE-exposed adults compared with litter-matched Control rats. Taken together, these findings demonstrate that binge-like exposure to alcohol during early to middle adolescence results in deficits in PFC-mediated behavioral control in adulthood.

Reward pathway dysfunction in gambling disorder: A meta-analysis of functional magnetic resonance imaging studies

Recent emerging functional magnetic resonance imaging (fMRI) studies have identified many brain regions in which gambling cues or rewards elicit activation and may shed light upon the ongoing disputes regarding the diagnostic and neuroscientific issues of gambling disorder (GD). However, no studies to date have systemically reviewed fMRI studies of GD to analyze the brain areas activated by gambling-related cues and examine whether these areas were differentially activated between cases and healthy controls (HC). This study reviewed 62 candidate articles and ultimately selected 13 qualified voxel-wise whole brain analysis studies to perform a comprehensive series of meta-analyses using the effect size-signed differential mapping approach. Compared with HC, GD patients showed significant activation in right lentiform nucleus and left middle occipital gyrus. The increased activities in the lentiform nucleus compared to HC were also found in both GD subgroups, regardless of excluding or not excluding any kind of substance use disorder. In addition, the South Oaks Gambling Screen scores were associated with hyperactivity in right lentiform nucleus and bilateral parahippocampus, but negatively related to right middle frontal gyrus. These results suggest dysfunction within the frontostriatal cortical pathway in GD, which could contribute to our understanding of the categories and definition of GD and provide evidence for the reclassification of GD as a behavioral addiction in the DSM-5.

Emotional processing and brain activity in youth at high risk for alcoholism

BACKGROUND

Even in the absence of heavy alcohol use, youth with familial alcoholism (family history positive [FHP]) exhibit atypical brain functioning and behavior. Although emotional and cognitive systems are affected in alcohol use disorders (AUDs), little attention has focused on whether brain and behavior phenotypes related to the interplay between affective and executive functioning may be a premorbid risk factor for the development of AUDs in FHP youth.

METHODS

Twenty-four FHP and 22 family history negative (FHN) 12- to 16-year-old adolescents completed study procedures. After exclusion of participants with clinically significant depressive symptoms and those who did not meet performance criteria during an Emotional Go-NoGo task, 19 FHP and 17 FHN youth were included in functional magnetic resonance imaging (fMRI) analyses. Resting state functional connectivity MRI, using amygdalar seed regions, was analyzed in 16 FHP and 18 FHN youth, after exclusion of participants with excessive head movement.

RESULTS

fMRI showed that brain activity in FHP youth, compared with FHN peers, was reduced during emotional processing in the superior temporal cortex, as well as during cognitive control within emotional contexts in frontal and striatal regions. Group differences in resting state amygdalar connectivity were seen bilaterally between FHP and FHN youth. In FHP youth, reduced resting state synchrony between the left amygdala and left superior frontal gyrus was related to poorer response inhibition, as measured during the fMRI task.

CONCLUSIONS

To our knowledge, this is the first study to examine emotion-cognition interactions and resting state functional connectivity in FHP youth. Findings from this research provide insight into neural and behavioral phenotypes associated with emotional processing in familial alcoholism, which may relate to increased risk of developing AUDs.