Decreased information processing speed and decision-making performance in alcohol use disorder: combined neurostructural evidence from VBM and TBSS

Testing the effect of high-definition transcranial direct current stimulation of the insular cortex to modulate decision-making and executive control

Introduction

Previous neuroimaging evidence highlighted the role of the insular and dorsal anterior cingulate cortex (dACC) in conflict monitoring and decision-making, thus supporting the translational implications of targeting these regions in neuro-stimulation treatments for clinical purposes. Recent advancements of targeting and modeling procedures for high-definition tDCS (HD-tDCS) provided methodological support for the stimulation of otherwise challenging targets, and a previous study confirmed that cathodal HD-tDCS of the dACC modulates executive control and decision-making metrics in healthy individuals. On the other hand, evidence on the effect of stimulating the insula is still needed.

Methods

We used a modeling/targeting procedure to investigate the effect of stimulating the posterior insula on Flanker and gambling tasks assessing, respectively, executive control and both loss and risk aversion in decision-making. HD-tDCS was applied through 6 small electrodes delivering anodal, cathodal or sham stimulation for 20 min in a within-subject offline design with three separate sessions.

Results

Bayesian statistical analyses on Flanker conflict effect, as well as loss and risk aversion, provided moderate evidence for the null model (i.e., absence of HD-tDCS modulation).

Discussion

These findings suggest that further research on the effect of HD-tDCS on different regions is required to define reliable targets for clinical applications. While modeling and targeting procedures for neuromodulation in clinical research could lead to innovative protocols for stand-alone treatment, or possibly in combination with cognitive training, assessing the effectiveness of insula stimulation might require sensitive metrics other than those investigated here.

Risky Decision-Making in Adults with Alcohol Use Disorder-A Systematic and Meta-Analytic Review

Alcohol use disorder (AUD) forms a major health concern and is the most common substance use disorder worldwide. The behavioural and cognitive deficits associated with AUD have often been related to impairments in risky decision-making. The aim of this study was to examine the magnitude and type of risky decision-making deficits of adults with AUD, as well as to explore the potential mechanisms behind these deficits. To this end, existing literature comparing risky decision-making task performance of an AUD group to a control group (CG) was systematically searched and analysed. A meta-analysis was performed to address overall effects. In total, 56 studies were included. In the majority of studies (i.e., 68%), the performance of the AUD group(s) deviated from the CG(s) on one or more of the adopted tasks, which was confirmed by a small to medium pooled effect size (Hedges' g = 0.45). This review therefore provides evidence of increased risk taking in adults with AUD as compared to CGs. The increased risk taking may be due to deficits in affective and deliberative decision-making. Making use of ecologically valid tasks, future research should investigate whether risky decision-making deficits predate and/or are consequential to the addiction of adults with AUD.

Functional Coherence in Intrinsic Frontal Executive Networks Predicts Cognitive Impairments in Alcohol Use Disorder

Growing evidence highlights the potential of innovative rehabilitative interventions such as cognitive remediation and neuromodulation, aimed at reducing relapses in Alcohol Use Disorder (AUD). Enhancing their effectiveness requires a thorough description of the neural correlates of cognitive alterations in AUD. Past related attempts, however, were limited by the focus on selected neuro-cognitive variables. We aimed to fill this gap by combining, in 22 AUD patients and 18 controls, an extensive neuro-cognitive evaluation and metrics of intrinsic connectivity as highlighted by resting-state brain activity. We addressed an inherent property of intrinsic activity such as intra-network coherence, the temporal correlation of the slow synchronous fluctuations within resting-state networks, representing an early biomarker of alterations in the functional brain architecture underlying cognitive functioning. AUD patients displayed executive impairments involving working-memory, attention and visuomotor speed, reflecting abnormal coherence of activity and grey matter atrophy within default mode, in addition to the attentional and the executive networks. The stronger relationship between fronto-lateral coherent activity and executive performance in patients than controls highlighted possible compensatory mechanisms counterbalancing the decreased functionality of networks driving the switch from automatic to controlled behavior. These results provide novel insights into AUD patients' cognitive impairments, their neural bases, and possible targets of rehabilitative interventions.

Alterations in white matter microstructure in alcohol and alcohol‐polydrug dependence: Associations with lifetime alcohol and nicotine exposure

Evidence suggests that alcohol dependence (AD) is associated with microstructural deficits in white matter, but the relationship with lifetime alcohol exposure and the impact of polydrug dependence is not well understood. Using diffusion tensor magnetic resonance (MR) imaging, we examined white matter microstructure in relation to alcohol and polydrug dependence using data from the Imperial College Cambridge Manchester (ICCAM) platform study. Tract‐based spatial statistics were used to examine fractional anisotropy (FA) in a cohort of abstinent AD participants, most of whom had a lifetime history of dependence to nicotine. A further subgroup also had a lifetime history of dependence to cocaine and/or opiates. Individuals with AD had lower FA throughout the corpus callosum, and negative associations with alcohol and nicotine exposure were found. A group‐by‐age interaction effect was found showing greater reductions with age in the alcohol‐dependent group within corpus callosum, overlapping with the group difference. We found no evidence of recovery with abstinence. A comparison of alcohol‐only‐ and alcohol‐polydrug‐dependent groups found no differences in FA. Overall, our findings show that AD is associated with lower FA and suggest that these alterations are primarily driven by lifetime alcohol consumption and cigarette smoking, showing no relationship with exposure to other substances such as cocaine, opiates or cannabis. Reductions in FA across the adult lifespan are more pronounced in AD and offer further support for the notion of accelerated ageing in relation to alcohol dependence. These findings highlight there may be lasting structural differences in white matter in alcohol dependence, despite continued abstinence.

Altered striatal-opercular intrinsic connectivity reflects decreased aversion to losses in alcohol use disorder

The persistence of addictive behaviours despite their adverse consequences highlights decreased punishment sensitivity as a facet of decision-making impairments in Alcohol Use Disorder (AUD). This attitude departs from the typical loss aversion (LA) pattern, i.e. the stronger sensitivity to negative than positive outcomes, previously associated with striatal and limbic-somatosensory responsiveness in healthy individuals. Consistent evidence highlights decreased LA as a marker of disease severity in AUD, but its neural bases remain largely unexplored. AUD-specific modulations of frontolateral activity by LA were previously related to the higher executive demands of anticipating losses than gains, but the relationship between LA and executive/working-memory performance in AUD is debated. Building on previous evidence of overlapping neural bases of LA during decision-making and at rest, we investigated a possible neural signature of altered LA in AUDs, and its connections with executive skills, in terms of complementary facets of resting-state functioning. In patients, smaller LA than controls, unrelated to executive performance, reflected reduced connectivity within striatal and medial temporal networks, and altered connectivity from these regions to the insular-opercular cortex. AUD-specific loss-related modulations of intrinsic connectivity thus involved structures previously associated both with drug-seeking and with coding the trade-off between appetitive and aversive motivational drives. These findings fit the hypothesis that altered striatal coding of choice-related incentive value, and interoceptive responsiveness to prospective outcomes, enhance neural sensitivity to drug-related stimuli in addictions. LA and its neural bases might prove useful markers of AUD severity and effectiveness of rehabilitation strategies targeting the salience of negative choice outcomes.

What Accounts for the Factors of Psychopathology? An Investigation of the Neurocognitive Correlates of Internalising, Externalising, and the p-Factor

Neurocognitive deficits have been consistently associated with a wide range of psychopathology and are proposed to not only be a consequence of the development of psychopathology but also directly involved in its aetiology. However, there is no clear understanding of what neurocognitive processes are particularly important to mental health. In this paper, we explored the association between neurocognitive abilities and the factors derived from structural models of psychopathology. Four hundred participants from a representative community sample completed measures of symptomology and substance use, as well as 8 neurocognitive tasks. We found a correlated-factors model, with internalising and externalising as the higher-order factors, and a single-factor model with only the p-factor, to be good fits for the data. Tasks that measured the speed of processing were significantly associated with internalising, externalising, and the p-factor, and accounted for significant amounts of unique variance in the factors after accounting for the common variance of the other tasks. Tasks that measured working memory, shifting, and inhibition were not significantly associated with psychopathology factors. Our findings suggest that neurocognitive abilities may not be differentially associated with psychopathology factors, but that speed of processing is a common correlate of the factors. We emphasise the importance of examining neurocognitive abilities and psychopathology on the individual level.

Increased decision latency in alcohol use disorder reflects altered resting-state synchrony in the anterior salience network

Increased decision latency in alcohol use disorder (AUD) has been generally explained in terms of psychomotor slowing. Recent results suggest that AUD patients' slowed decision-making might rather reflect alterations in the neural circuitry underlying the engagement of controlled processing by salient stimuli. We addressed this hypothesis by testing a relationship between decision latency at the Cambridge Gambling Task (CGT) and intrinsic brain activity in 22 individuals with AUD and 19 matched controls. CGT deliberation time was related to two complementary facets of resting-state fMRI activity, i.e. coherence and intensity, representing early biomarkers of functional changes in the intrinsic brain architecture. For both metrics, we assessed a multiple regression (to test a relationship with deliberation time in the whole sample), and an interaction analysis (to test a significantly different relationship with decision latency across groups). AUD patients' slowed deliberation time (p < 0.025) reflected distinct facets of altered intrinsic activity in the cingulate node of the anterior salience network previously associated with the "output" motor stage of response selection. Its heightened activity in AUD patients compared with controls, tracking choice latency (p < 0.025 corrected), might represent a compensation mechanism counterbalancing the concurrent decrease of its internal coherent activity (p < 0.025 corrected). These findings provide novel insights into the intrinsic neural mechanisms underlying increased decision latency in AUD, involving decreased temporal synchronicity in networks promoting executive control by behaviourally relevant stimuli. These results pave the way to further studies assessing more subtle facets of decision-making in AUD, and their possible changes with rehabilitative treatment.

Shared gray matter alterations in subtypes of addiction: a voxel-wise meta-analysis

BACKGROUND

Numerous studies based on voxel-based morphometry (VBM) have revealed gray matter (GM) alterations in multiple brain regions for addiction. However, findings are poorly replicated, and it remains elusive whether distinct diagnoses of addiction are underpinned by shared abnormalities. Our aim was to conduct a quantitative meta-analysis of structural neuroimaging studies investigating GM abnormalities in two main categories of addiction: substance use disorders (SUD) and behavioral addictions (BA).

METHOD

A systematic database search was conducted in several databases from Jan 1, 2010, to Oct 23, 2020, to identify eligible VBM studies. Meta-analysis was performed with the seed-based d mapping software package to compare alternations between individuals with addiction-related disorders and healthy controls (HC).

RESULTS

A total of 59 VBM studies including 2096 individuals with addiction-related disorders and 2637 HC met the inclusion criteria. Individuals with addiction-related disorders showed shared GM volume decrease in bilateral prefrontal cortex, bilateral insula, bilateral rolandic operculum, left superior temporal gyrus, and right Heschl gyrus and GM increase in right lingual gyrus and right fusiform gyrus comparing with HC (p < 0.005). Subgroup analysis found heterogeneity between SUD and BA mainly in left inferior occipital gyrus and right striatum (p < 0.005). Meta-regression revealed that GM atrophy in right anterior cingulate (r = 0.541, p = 0.03 (uncorrected)) and left inferior frontal gyrus (r = 0.595, p = 0.015) were positively correlated with higher impulsivity.

CONCLUSIONS

This meta-analysis identified a concordance across subtypes of addiction in terms of the brain structural changes in prefrontal and insula areas, which may relate to higher impulsivity observed across addiction diagnoses. This concordance provides an organizing model that emphasizes the importance of shared neural substrates in addiction.

Common abnormality of gray matter integrity in substance use disorder and obsessive-compulsive disorder: A comparative voxel-based meta-analysis

The objective of the current study is to determine robust transdiagnostic brain structural markers for compulsivity by capitalizing on the increasing number of case‐control studies examining gray matter volume (GMV) alterations in substance use disorders (SUD) and obsessive‐compulsive disorder (OCD). Voxel‐based meta‐analysis within the individual disorders and conjunction analysis were employed to reveal common GMV alterations between SUDs and OCD. Meta‐analytic coordinates and signed brain volumetric maps determining directed (reduced/increased) GMV alterations between the disorder groups and controls served as the primary outcome. The separate meta‐analysis demonstrated that SUD and OCD patients exhibited widespread GMV reductions in frontocortical regions including prefrontal, cingulate, and insular. Conjunction analysis revealed that the left inferior frontal gyrus (IFG) consistently exhibited decreased GMV across all disorders. Functional characterization suggests that the IFG represents a core hub in the cognitive control network and exhibits bidirectional (Granger) causal interactions with the striatum. Only OCD showed increased GMV in the dorsal striatum with higher changes being associated with more severe OCD symptomatology. Together the findings demonstrate robustly decreased GMV across the disorders in the left IFG, suggesting a transdiagnostic brain structural marker. The functional characterization as a key hub in the cognitive control network and casual interactions with the striatum suggest that deficits in inhibitory control mechanisms may promote compulsivity and loss of control that characterize both disorders.

Meta-analysis of grey matter changes and their behavioral characterization in patients with alcohol use disorder

Alcohol Use Disorder (AUD) is associated with reductions in grey matter (GM) volume which can lead to changes in numerous brain functions. The results of previous studies on altered GM in AUD differ considerably in the regions identified. Three meta-analyses carried out between 2014 and 2017 yielded different results. The present study includes the considerable amount of newer research and delivers a state-of-the art meta-analysis in line with recently published guidelines. Additionally, we behaviorally characterized affected regions using fMRI metadata and identified related brain networks by determining their meta-analytic connectivity patterns. Twenty-seven studies with 1,045 AUD patients and 1,054 healthy controls were included in the analysis and analyzed by means of Anatomical Likelihood Estimation (ALE). GM alterations were identified in eight clusters covering different parts of the cingulate and medial frontal gyri, paracentral lobes, left post- and precentral gyri, left anterior and right posterior insulae and left superior frontal gyrus. The behavioral characterization associated these regions with specific cognitive, emotional, somatosensory and motor functions. Moreover, the clusters represent nodes within behaviorally relevant brain networks. Our results suggest that GM reduction in AUD could disrupt network communication responsible for the neurocognitive impairments associated with high chronic alcohol consumption.

Changes in Loss Sensitivity During Treatment in Concurrent Disorders Inpatients: A Computational Model Approach to Assessing Risky Decision-Making

BACKGROUND

Recent studies have employed computational modeling to characterize deficits in aspects of decision-making not otherwise detected using traditional behavioral task outcomes. While prospect utility-based modeling has shown to differentiate decision-making patterns between users of different drugs, its relevance in the context of treatment has yet to be examined. This study investigated model-based decision-making as it relates to treatment outcome in inpatients with co-occurring mental health and substance use disorders.

METHODS

50 patients (Mage = 38.5, SD = 11.4; 16F) completed the Cambridge Gambling Task (CGT) within 2 weeks of admission (baseline) and 6 months into treatment (follow-up), and 50 controls (Mage = 31.9, SD = 10.0; 25F) completed CGT under a single outpatient session. We evaluated 4 traditional CGT outputs and 5 decisional processes derived from the Cumulative Model. Psychiatric diagnoses and discharge data were retrieved from patient health records.

RESULTS

Groups were similar in age, sex, and premorbid IQ. Differences in years of education were included as covariates across all group comparisons. All patients had ≥1 mental health diagnosis, with 80% having >1 substance use disorder. On the CGT, patients showed greater Deliberation Time and Delay Aversion than controls. Estimated model parameters revealed higher Delayed Reward Discounting, and lower Probability Distortion and Loss Sensitivity in patients relative to controls. From baseline to follow-up, patients (n = 24) showed a decrease in model-derived Loss Sensitivity and Color Choice Bias. Lastly, poorer Quality of Decision-Making and Choice Consistency, and greater Color Choice Bias independently predicted higher likelihood of treatment dropout, while none were significant in relation to treatment length of stay.

CONCLUSION

This is the first study to assess a computational model of decision-making in the context of treatment for concurrent disorders. Patients were more impulsive and slower to deliberate choice than controls. While both traditional and computational outcomes predicted treatment adherence in patients, findings suggest computational methods are able to capture treatment-sensitive aspects of decision-making not accessible via traditional methods. Further research is needed to confirm findings as well as investigate the relationship between model-based decision-making and post-treatment outcomes.

Impaired learning from regret and disappointment in alcohol use disorder

The development of alcohol habits is considered a form of maladaptive reinforced learning, with sustained alcohol use resulting in the strengthening of associative links between consumption and either rewarding, or the lack of aversive, experiences. Despite recent efforts in characterizing decision-making skills in alcohol-use-disorder (AUD), it is still unknown whether impaired behavioural learning in AUD patients reflects a defective processing and anticipation of choice-related, cognitively mediated, emotions such as regret or relief for what might have been under a different choice. We administered a Wheel-of-Fortune (WoF) task to 26 AUD patients and 19 healthy controls, to investigate possible alterations in adjusting choices to the magnitude of experienced regret/relief, and in other facets of decision-making performance such as choice latency. AUD patients displayed both longer deliberation time than healthy controls, and impaired adaptations to previous outcome-related negative emotions. Although further evidence is needed to unveil the cognitive mechanisms underlying AUD patients’ abnormal choice, the present results highlight important implications for the clinical practice, e.g. in terms of cognitive treatments aiming to shape faulty perceptions about negative emotions associated with excessive alcohol exposure.

Heterogeneity of Executive Function Abilities in Recently Detoxified Patients with Alcohol Use Disorder: Evidence from a Cluster Analysis

BACKGROUND

Impairments of executive functions (EF) have been consistently reported in patients with alcohol use disorder (AUD), mostly in studies which were based on comparisons of means between groups. However, given the high heterogeneity in AUD patients, this approach could actually cover a wide range of EF patterns. In the present study, we addressed the paucity of the literature about cognitive heterogeneity in AUD by applying a cluster analytical approach on EF measures.

METHODS

Seventy-eight withdrawn AUD patients and 77 healthy Control participants completed measures targeting a variety of EF components. We then used cluster analysis to identify subgroups of AUD patients. Furthermore, the AUD subgroups were compared to the Control group to establish their specific EF patterns.

RESULTS

Findings showed that AUD patients could be divided into 3 clusters based on their EF performances. A first cluster accounting for half of the AUD sample was characterized by unimpaired EF (Cluster 1). The 2 other clusters displayed major EF deficits but differed regarding the deficient EF component. While Cluster 2 was mainly impaired on measures of rule deduction and mental flexibility, Cluster 3 was mainly characterized by a lower processing speed and impaired inhibition of an ongoing motor response. Differences in EF performances of AUD patients could be related to differences in premorbid cognitive reserve, impulsiveness patterns, and withdrawal complications.

CONCLUSIONS

This study highlights the importance of the cognitive heterogeneity in AUD by showing that AUD patients display substantially different EF patterns. Future studies should try to go beyond mere group comparisons to further deepen our understanding about cognitive differences between AUD patients. In the long run, this could lead to more personalized prevention and treatment programs specifically tailored to the patient's impairments.