Neuropsychological deficits are correlated with frontal hypometabolism in positron emission tomography studies of older alcoholic patients

Neuropsychiatric Alterations in a Patient Diagnosed with Advanced Korsakoff's Syndrome: Clinical Case of Low Incidence and Prevalence in Colombia

Korsakoff's syndrome (KS) is an insidious and progressive neuropsychiatric disorder that affects specific neurocognitive functioning, especially in tasks that require sustained attention, memory, executive functions, and visuospatial functioning. Usually, this disease generates neuropsychiatric complications that worsen the quality of life (QOL) of patients in the medium term. We present a case of a 63-year-old male who presented with a diagnosis of advanced Korsakoff's syndrome and has a clinical history of recurrent memory loss and a history of alcohol abuse. The patient showed difficulty manipulating immediate information, associated with a possible frontal lobe dysfunction, and inability to remember material given through the auditory pathway. The patient showed a psychiatric clinical picture which is constantly worsening his and his immediate caregiver's QOL. The data obtained demonstrate that the patient presents a progressive cognitive impairment, which in the short term is correlated with Korsakoff-type dementia. It is suggested to carry out functional neurorehabilitation plans aimed at improving the QOL of the patient, his immediate caregiver, and future people with this type of diagnosis.

Quantitative electroencephalographic analysis of delirium tremens development following alcohol-withdrawal seizure based on a small number of male cases

INTRODUCTION

Seizures and delirium tremens (DTs) are recognized as severe alcohol-withdrawal symptoms. Prolonged admission and serious complications associated with alcohol withdrawal are responsible for increased costs and use of medical and social resources. This study investigated the predictive value of quantitative electroencephalography (QEEG) for developing alcohol-related DTs after alcohol-withdrawal seizure (AWS).

METHODS

We compared differences in QEEG in patients after AWS (n = 13). QEEG was performed in the intensive care unit within 48 h of admission, including in age- and sex-matched healthy controls. We also investigated the prognostic value of QEEG for the development of alcohol DTs after AWS in a retrospective, case-control study. The spectral power of each band frequency and the ratio of the theta to alpha band (TAR) in the electroencephalogram were analyzed using iSyncBrain^® (iMediSync, Inc., Korea).

RESULTS

The beta frequency and the alpha frequency band power were significantly higher and lower, respectively, in patients than in age- and sex-matched healthy controls. In AWS patients with DTs, the relative beta-3 power was lower, particularly in the left frontal area, and the TAR was significantly higher in the central channel than in those without DTs.

CONCLUSION

Quantitative EEG showed neuronal excitability and decreased cognitive activities characteristic of AWS associated with alcohol-withdrawal state, and we demonstrated that quantitative EEG might be a helpful tool for detecting patients at a high risk of developing DTs during an alcohol-dependence period.

Fluorodeoxyglucose positron emission tomography scans in patients with alcohol use disorder

BACKGROUND

Diminished uptake of fluorodeoxyglucose (FDG) has been observed in patients with alcohol use disorder (AUD) but little statistical contrast of the regional brain deficits has been undertaken. This study examined prefrontal cortex inter-regional Brodmann area differences to delineate patterns associated with behavioral, neurotransmitter, and general toxicity hypotheses of cerebral involvement in AUD.

METHODS

We obtained data from FDG positron emission tomography (PET) and anatomical magnetic resonance imaging (MRI) for 87 patients with AUD and 41 age- and sex-matched healthy volunteers. Patients were alcohol dependent and had negative breathalyzer tests at the time of imaging. They were assessed with the Beck Depression Inventory, Alcohol Urge Questionnaire, Obsessive Compulsive Drinking Scale, Spielberger State/Trait Anxiety Scale, Buss-Durkee Hostility Inventory, and the Drinker Inventory of Consequences (DrInC). PET images were co-registered to MRI and both voxel × voxel statistical mapping and stereotaxic regions of interest were obtained.

RESULTS

Compared with healthy volunteers, patients with AUD had lower relative metabolic rates in the frontal, temporal, and parietal lobes, localizable most prominently to the dorsolateral and nearly all orbital prefrontal cortex, superior temporal gyrus, and inferior parietal lobule. In contrast, metabolic rates in the medial orbitofrontal and anterior cingulate cortex, and the subcortical structures (thalamus, cerebellum, ventral striatum, and the dorsal raphe nucleus) in patients were significantly greater. The severity of alcohol-related consequences as assessed by the DrInC scale was most highly associated with lower metabolism in the caudate, dorsolateral prefrontal, frontopolar, and anteroposterior cingulate cortex.

CONCLUSIONS

Despite widespread metabolic abnormalities, decreases in AUD were most marked in frontal executive areas, consistent with diminished impulse control, and increases were most prominent in the striatum and cingulate areas, consistent with a suppressed reward system.

Changes in Hemodynamic Response Function Resulting From Chronic Alcohol Consumption

BACKGROUND

Functional MRI (fMRI) task-related analyses rely on an estimate of the brain's hemodynamic response function (HRF) to model the brain's response to events. Although changes in the HRF have been found after acute alcohol administration, the effects of heavy chronic alcohol consumption on the HRF have not been explored, and the potential benefits or pitfalls of estimating each individual's HRF on fMRI analyses of chronic alcohol use disorder (AUD) are not known.

METHODS

Participants with AUD and controls (CTL) received structural, functional, and vascular scans. During fMRI, participants were cued to tap their fingers, and averaged responses were extracted from the motor cortex. Curve fitting on these HRFs modeled them as a difference between 2 gamma distributions, and the temporal occurrence of the main peak and undershoot of the HRF was computed from the mean of the first and second gamma distributions, respectively.

RESULTS

ANOVA and regression analyses found that the timing of the HRF undershoot increased significantly as a function of total lifetime drinking. Although gray matter volume in the motor cortex decreased with lifetime drinking, this was not sufficient to explain undershoot timing shifts, and vascular factors measured in the motor cortex did not differ among groups. Comparison of random-effects analyses using custom-fitted and canonical HRFs for CTL and AUD groups showed better results throughout the brain for custom-fitted versus canonical HRFs for CTL subjects. For AUD subjects, the same was true except for the basal ganglia.

CONCLUSIONS

These findings suggest that excessive alcohol consumption is associated with changes in the HRF undershoot. HRF changes could provide a possible biomarker for the effects of lifetime drinking on brain function. Changes in HRF topography affect fMRI activation measures, and subject-specific HRFs generally improve fMRI activation results.

Addictions NeuroImaging Assessment (ANIA): Towards an integrative framework for alcohol use disorder

Alcohol misuse and addiction are major international public health issues. Addiction can be characterized as a disorder of aberrant neurocircuitry interacting with environmental, genetic and social factors. Neuroimaging in alcohol misuse can thus provide a critical window into underlying neural mechanisms, highlighting possible treatment targets and acting as clinical biomarkers for predicting risk and treatment outcomes. This neuroimaging review on alcohol misuse in humans follows the Addictions Neuroclinical Assessment (ANA) that proposes incorporating three functional neuroscience domains integral to the neurocircuitry of addiction: incentive salience and habits, negative emotional states, and executive function within the context of the addiction cycle. Here we review and integrate multiple imaging modalities focusing on underlying cognitive processes such as reward anticipation, negative emotionality, cue reactivity, impulsivity, compulsivity and executive function. We highlight limitations in the literature and propose a model forward in the use of neuroimaging as a tool to understanding underlying mechanisms and potential clinical applicability for phenotyping of heterogeneity and predicting risk and treatment outcomes.

Intranasal Insulin: a Treatment Strategy for Addiction

Addiction to substances such as alcohol, cocaine, opioids, and methamphetamine poses a continuing clinical and public challenge globally. Despite progress in understanding substance use disorders, challenges remain in their treatment. Some of these challenges include limited ability of therapeutics to reach the brain (blood-brain barrier), adverse systemic side effects of current medications, and importantly key aspects of addiction not addressed by currently available treatments (such as cognitive impairment). Inability to sustain abstinence or seek treatment due to cognitive deficits such as poor decision-making and impulsivity is known to cause poor treatment outcomes. In this review, we provide an evidenced-based rationale for intranasal drug delivery as a viable and safe treatment modality to bypass the blood-brain barrier and target insulin to the brain to improve the treatment of addiction. Intranasal insulin with improvement of brain cell energy and glucose metabolism, stress hormone reduction, and improved monoamine transmission may be an ideal approach for treating multiple domains of addiction including memory and impulsivity. This may provide additional benefits to enhance current treatment approaches.

Aging with alcohol-related brain damage: Critical brain circuits associated with cognitive dysfunction

Alcoholism is associated with brain damage and impaired cognitive functioning. The relative contributions of different etiological factors, such as alcohol, thiamine deficiency and age vulnerability, to the development of alcohol-related neuropathology and cognitive impairment are still poorly understood. One reason for this quandary is that both alcohol toxicity and thiamine deficiency produce brain damage and cognitive problems that can be modulated by age at exposure, aging following alcohol toxicity or thiamine deficiency, and aging during chronic alcohol exposure. Pre-clinical models of alcohol-related brain damage (ARBD) have elucidated some of the contributions of ethanol toxicity and thiamine deficiency to neuroinflammation, neuronal loss and functional deficits. However, the critical variable of age at the time of exposure or long-term aging with ARBD has been relatively ignored. Acute thiamine deficiency created a massive increase in neuroimmune genes and proteins within the thalamus and significant increases within the hippocampus and frontal cortex. Chronic ethanol treatment throughout adulthood produced very minor fluctuations in neuroimmune genes, regardless of brain region. Intermittent "binge-type" ethanol during the adolescent period established an intermediate neuroinflammatory response in the hippocampus and frontal cortex, that can persist into adulthood. Chronic excessive drinking throughout adulthood, adolescent intermittent ethanol exposure, and thiamine deficiency all led to a loss of the cholinergic neuronal phenotype within the basal forebrain, reduced hippocampal neurogenesis, and alterations in the frontal cortex. Only thiamine deficiency results in gross pathological lesions of the thalamus. The behavioral impairment following these types of treatments is hierarchical: Thiamine deficiency produces the greatest impairment of hippocampal- and prefrontal-dependent behaviors, chronic ethanol drinking ensues mild impairments on both types of tasks and adolescent intermittent ethanol exposure leads to impairments on frontocortical tasks, with sparing on most hippocampal-dependent tasks. However, our preliminary data suggest that as rodents age following adolescent intermittent ethanol exposure, hippocampal functional deficits began to emerge. A necessary requirement for the advancement of understanding the neural consequences of alcoholism is a more comprehensive assessment and understanding of how excessive alcohol drinking at different development periods (adolescence, early adulthood, middle-aged and aged) influences the trajectory of the aging process, including pathological aging and disease.

Brain-behavior relations and effects of aging and common comorbidities in alcohol use disorder: A review

OBJECTIVE

Alcohol use disorder (AUD) is a complex, dynamic condition that waxes and wanes with unhealthy drinking episodes and varies in drinking patterns and effects on brain structure and function with age. Its excessive use renders chronically heavy drinkers vulnerable to direct alcohol toxicity and a variety of comorbidities attributable to nonalcohol drug misuse, viral infections, and accelerated or premature aging. AUD affects widespread brain systems, commonly, frontolimbic, frontostriatal, and frontocerebellar networks.

METHOD AND RESULTS

Multimodal assessment using selective neuropsychological testing and whole-brain neuroimaging provides evidence for AUD-related specific brain structure-function relations established with double dissociations. Longitudinal study using noninvasive imaging provides evidence for brain structural and functional improvement with sustained sobriety and further decline with relapse. Functional imaging suggests the possibility that some alcoholics in recovery can compensate for impairment by invoking brain systems typically not used for a target task but that can enable normal-level performance.

CONCLUSIONS

Evidence for AUD-aging interactions, indicative of accelerated aging, together with increasing alcohol consumption in middle-age and older adults, put aging drinkers at special risk for developing cognitive decline and possibly dementia. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Association Between Reduced Brain Glucose Metabolism and Cortical Thickness in Alcoholics: Evidence of Neurotoxicity

BACKGROUND

Excessive alcohol consumption is associated with reduced cortical thickness (CT) and lower cerebral metabolic rate of glucose (CMRGlu), but the correlation between these 2 measures has not been investigated.

METHODS

We tested the association between CT and cerebral CMRGlu in 19 participants with alcohol use disorder (AUD) and 20 healthy controls. Participants underwent 2-Deoxy-2-[18F]fluoroglucose positron emission tomography to map CMRGlu and magnetic resonance imaging to assess CT.

RESULTS

Although performance accuracy on a broad range of cognitive domains did not differ significantly between AUD and HC, AUD had widespread decreases in CT and CMRGlu. CMRGlu, normalized to cerebellum (rCMRGlu), showed significant correlation with CT across participants. Although there were large group differences in CMRGlu (>17%) and CT (>6%) in medial orbitofrontal and BA 47, the superior parietal cortex showed large reductions in CMRGlu (~17%) and minimal CT differences (~2.2%). Though total lifetime alcohol (TLA) was associated with CT and rCMRGlu, the causal mediation analysis revealed significant direct effects of TLA on rCMRGlu but not on CT, and there were no significant mediation effects of TLA, CT, and rCMRGlu.

CONCLUSIONS

The significant correlation between decrements in CT and CMRGlu across AUD participants is suggestive of alcohol-induced neurotoxicity, whereas the findings that the most metabolically affected regions in AUD had minimal atrophy and vice versa indicates that changes in CT and CMRGlu reflect distinct responses to alcohol across brain regions.

On the Neurobiological Role of Oxidative Stress in Alcohol-Induced Impulsive, Aggressive and Suicidal Behavior

Objectives: Alcohol abuse is known to result in behavioral impairments (such as increased impulsivity, aggressive, and suicidal behavior), but the neurobiological basis for these behavioral impairments remains unknown. The objective of this review is to propose a neurobiological basis for alcohol-induced aggression, impulsivity, and suicidal behavior. Methods: Search was done by accessing PubMed/Medline, EBSCO, and PsycINFO databases. The search string used was "(Alcohol OR Alcoholism* OR Alcohol Abuse) AND (Behavior* OR Behavioral Impairment or Disorder) AND (Oxidative Stress OR Reactive Oxygen Species)." The electronic databases were searched for titles or abstracts containing these terms in all published articles between January 1, 1960, and May 31, 2019. The search was limited to studies published in English and other languages involving both animal and human subjects. Articles selected included randomized clinical trials (RCTs), observational studies, meta-analyses, and both systemic and narrative reviews, providing both quantitative and qualitative information with a measure of alcohol abuse or alcoholism as an outcome. Exclusion criteria were unpublished data of any form, including conference proceedings and dissertation. New key terms were identified (new term included: "Antioxidants, Neurotransmitters, Dopamine, Serotonin, GABA, Glutamate. Aggression, Impulsivity, Suicidal Behavior, hippocampus, prefrontal cortex, limbic system, psychiatric disorders, PTSD, Anxiety, Depression. These new terms were searched with Alcohol or Alcoholism or Alcohol Abuse and Oxidative Stress separately resulting in the identification of over 3000 articles. 196 were included in this article. Results: Multiple lines of evidence indicate that oxidative stress (OS) plays a critical underlying role in alcohol toxicity and behavioral impairments. Conclusions/Importance: People diagnosed with PTSD, anxiety disorder, depression, and those with a personality high in psychoticism as measured by the P Scale of the Eysenck Personality Questionnaire, with comorbid alcohol abuse or alcohol use disorder (AUD), may display increased impulsivity, aggression, and suicidal behavior because of the potentiating effect of alcohol-induced OS on their elevated brain oxidative status. Antioxidant therapy should be an integral part of acute alcohol intoxication and AUD treatment. Further research is necessary to fully understand the relationship between OS and alcohol-induced behavioral impairments.

Light social drinkers are more distracted by irrelevant information from an induced attentional bias than heavy social drinkers

It is well established that alcoholics and heavy social drinkers show a bias of attention towards alcohol-related items. Previous research suggests that there is a shared foundation of attentional bias, which is linked to attentional control settings. Specifically, attentional bias relates to a persistent selection of a Feature Search Mode which prioritises attentional bias-related information for selection and processing. However, no research has yet examined the effect of pre-existing biases on the development of an additional attentional bias. This paper seeks to discover how pre-existing biases affect the formation of a new, additional attentional bias. Twenty-five heavy and 25 light social drinkers, with and without a pre-existing bias to alcohol-related items, respectively, had an attentional bias towards the colour green induced via an information sheet. They then completed a series of one-shot change detection tasks. In the critical task, green items were present but task-irrelevant. Irrelevant green items caused significantly more interference for light than heavy social drinkers. This somewhat counter intuitive result is likely due to heavy drinkers having more experience in exerting cognitive control over attentional biases, something not previously observed in investigations of the effects of holding an attentional bias. Our findings demonstrate for the first time that an established attentional bias significantly modulates future behaviour.

Changes in cerebral [18F]-FDG uptake induced by acute alcohol administration in a rat model of alcoholism

Several [¹⁸F]-FDG positron emission tomography (PET) studies in alcoholics have consistently reported decreases in overall brain glucose metabolism at rest and following acute alcohol administration. However, changes in cerebral glucose utilization associated with the transition to addiction are not well understood and require longitudinal translational imaging studies in animal models of alcoholism. Here, we studied brain glucose uptake in alcohol drinking rats in order to provide convergent evidence to what has previously been reported in human studies. Brain glucose metabolism was measured by [¹⁸F]-FDG microPET imaging in different male Wistar rat groups: short-term drinking (three months), long-term drinking (twelve months) and alcohol-naïve. Global and regional cerebral glucose uptake was measured at rest and following acute alcohol administration. We showed that alcohol significantly reduced the whole-brain glucose metabolism. This effect was most pronounced in the parietal cortex and cerebellum. Alcohol-induced decreases in brain [¹⁸F]-FDG uptake was most apparent in alcohol-naïve rats, less intense in short-term drinkers and absent in long-term drinkers. The latter finding indicates the occurrence of tolerance to the intoxicating effects of alcohol in long-term drinking individuals. In contrast, some regions, like the ventral striatum and entorhinal cortex, showed enhanced metabolic activity, an effect that did not undergo tolerance during long-term alcohol consumption. Our findings are comparable to those described in human studies using the same methodology. We conclude that [¹⁸F]-FDG PET studies in rat models of alcoholism provide good translation and can be used for future longitudinal studies investigating alterations in brain function during different stages of the addiction cycle.

Specificity of executive functioning and processing speed problems in common psychopathology

OBJECTIVE

Interest continues in neuropsychological measures as cross-disorder intermediate phenotypes in understanding psychopathology. A central question concerns their specificity versus generalizability to particular forms of psychopathology, particularly for executive functioning (EF) and response speed. Three conceptual models examining these relationships were tested to clarify this picture at different levels in the diagnostic hierarchy.

METHOD

Participants (total n = 641, age 18-60) yielded complete structured diagnostic interviews and a neuropsychological test battery comprising measures of executive function, processing speed, and IQ. Repeated measures multivariate analysis of variance, linear regression, and structural equation modeling (SEM) were used to test (a) a specificity model, which proposes that individual disorders are associated with component EF processes and speed; (b) a severity model, which proposes that the total number of comorbid disorders explain poor EF and/or slow speed; and (c) a higher-order dimensional model, which proposes that internalizing versus externalizing disorders are differentially related to EF or speed.

RESULTS

EF effects were best explained by a specificity model, with distinct aspects of EF related to attention deficit hyperactivity disorder versus antisocial substance use disorders. Speed, on the other hand, emerged as a general indicator of externalizing psychopathology in the dimensional model, as well as overall severity of psychopathology in the severity model.

CONCLUSIONS

Granular approaches are likely to be most productive for linking EF to psychopathology, whereas response speed has underused potential as an endophenotype for psychopathology liability. Results are discussed in terms of an integrated conceptualization of neuropsychological processes and putative neural systems involved in general and specific aspects of psychopathology. (PsycINFO Database Record

Prefrontal Cortical Thickness Deficit in Detoxified Alcohol-dependent Patients

Alcohol dependence is a serious disorder that can be related with a number of potential health-related and social consequences. Cortical thickness measurements would provide important information on the cortical structural alterations in patients with alcohol dependence. Twenty-one patients with alcohol dependence and 22 healthy comparison subjects have been recruited and underwent high-resolution brain magnetic resonance (MR) imaging and clinical assessments. T1-weighted MR images were analyzed using the cortical thickness analysis program. Significantly thinner cortical thickness in patients with alcohol dependence than healthy comparison subjects was noted in the left superior frontal cortical region, correcting for multiple comparisons and adjusting with age and hemispheric average cortical thickness. There was a significant association between thickness in the cluster of the left superior frontal cortex and the duration of alcohol use. The prefrontal cortical region may particularly be vulnerable to chronic alcohol exposure. It is also possible that the pre-existing deficit in this region may have rendered individuals more susceptible to alcohol dependence.

Behavioral impulsivity mediates the relationship between decreased frontal gray matter volume and harmful alcohol drinking: A voxel-based morphometry study

Alcohol use disorder (AUD) with harmful drinking patterns is on the one hand characterized by impulsive behavior and is on the other hand known to involve structural brain alterations with lower gray matter volume (GMV), especially in the prefrontal cortex (PFC). So far it is unclear whether frontal brain volumes are associated to harmful alcohol drinking and impulsivity, while controlling simultaneously for a wide array of important confounding factors, which are related to alcohol consumption. We used voxel-based morphometry in 99 adults ranging within a continuum of normal to harmful drinking behavior and alcohol dependence, measured by the 'Alcohol Use Disorders Identification Test', to examine whether the severity of harmful drinking is correlated with structural markers, in particular in the PFC and whether such markers are linked to self-reported impulsivity. We included alcohol and nicotine lifetime exposure, age, education, and BMI as covariates to control that GMV decreases were not related to those factors. Harmful drinking was associated with lower GMV in the right frontal pole, left inferior frontal gyrus, and bilateral inferior parietal lobe. GMV loss in the PFC regions was correlated with increased impulsivity. Follow-up mediation analyses showed that the relationship between GMV in the frontal pole and harmful drinking was mediated by impulsivity. Our findings show that PFC reductions are associated with harmful drinking and impulsivity. Our data suggest that reduced frontal pole GM, independent of a number of alcohol drinking associated covariates, e.g. lifetime alcohol consumption, is related to impaired top-down control of alcohol drinking behavior.

An Update of the Review of Neuropsychological Consequences of HIV and Substance Abuse: A Literature Review and Implications for Treatment and Future Research

Neuropyschological dysfunction, ranging from mild cerebral indicators to dementia has been a consistent part of the medical picture of HIV/AIDS. However, advances in medical supervision, particularly as a result of antiretroviral (ARV) treatment, have resulted in some mitigation of the neuropsychological effects of HIV and necessitate re-evaluation of the pattern and nature of HIV-related cognitive or mental deficits. The associated enhancements in morbidity and mortality that have occurred as a result of ARV medication have led to a need for interventions and programs that maintain behaviors that are healthy and stop the resurgence of the risk of HIV transmission. Risk factors such as mental illness and substance use that may have contributed to the initial infection with HIV still need consideration. These risk factors may also increase neuropsychological dysfunction and impact observance of prevention for treatment and recommendations. Explicitly, a better comprehension of the role of substance use on the progression of HIV-related mental decline can enlighten management and evaluation of persons living with HIV with concurrent disorders of substance use. This review provides a summary of the neurophyschology of substance use and HIV and the existing research that has looked at the effects of both substance use and HIV disease on neurophyscological function and suggestions for future research and treatment.

Polygenic risk for alcohol dependence associates with alcohol consumption, cognitive function and social deprivation in a population-based cohort

Alcohol dependence is frequently co‐morbid with cognitive impairment. The relationship between these traits is complex as cognitive dysfunction may arise as a consequence of heavy drinking or exist prior to the onset of dependence. In the present study, we tested the genetic overlap between cognitive abilities and alcohol dependence using polygenic risk scores (PGRS). We created two independent PGRS derived from two recent genome‐wide association studies (GWAS) of alcohol dependence (SAGE GWAS: n = 2750; Yale‐Penn GWAS: n = 2377) in a population‐based cohort, Generation Scotland: Scottish Family Health Study (GS:SFHS) (n = 9863). Data on alcohol consumption and four tests of cognitive function [Mill Hill Vocabulary (MHV), digit symbol coding, phonemic verbal fluency (VF) and logical memory] were available. PGRS for alcohol dependence were negatively associated with two measures of cognitive function: MHV (SAGE: P = 0.009, β = −0.027; Yale‐Penn: P = 0.001, β = −0.034) and VF (SAGE: P = 0.0008, β = −0.036; Yale‐Penn: P = 0.00005, β = −0.044). VF remained robustly associated after adjustment for education and social deprivation; however, the association with MHV was substantially attenuated. Shared genetic variants may account for some of the phenotypic association between cognitive ability and alcohol dependence. A significant negative association between PGRS and social deprivation was found (SAGE: P = 5.2 × 10⁻⁷, β = −0.054; Yale‐Penn: P = 0.000012, β = −0.047). Individuals living in socially deprived regions were found to carry more alcohol dependence risk alleles which may contribute to the increased prevalence of problem drinking in regions of deprivation. Future work to identify genes which affect both cognitive impairment and alcohol dependence will help elucidate biological processes common to both disorders.

Brain perfusion in polysubstance users: relationship to substance and tobacco use, cognition, and self-regulation

BACKGROUND

Brain perfusion is altered in both alcohol dependence and stimulant dependence. Although most substance users also abuse/depend on alcohol concurrently (polysubstance users; PSU), rigorous perfusion research in PSU is limited. Also, the relationships of perfusion abnormalities with cognition, impulsivity, or decision making are not well known.

METHODS

Arterial spin labeling MRI and neuropsychological measures assessed perfusion levels and neurocognition in 20 alcohol-dependent individuals with comorbid-stimulant dependence (PSU), 26 individuals dependent on alcohol only (ALC), and 31 light/non-drinking controls (LD). The patient groups included smokers and non-smokers.

RESULTS

ALC had lower perfusion than LD in subcortical and cortical brain regions including the brain reward/executive oversight system (BREOS). Contrary to our hypothesis, regional perfusion was generally not lower in PSU than ALC. However, smoking PSU had lower perfusion than smoking ALC in several regions, including BREOS. Lower BREOS perfusion related to greater drinking severity in smoking substance users and to greater smoking severity in smoking ALC. Lower regional perfusion in ALC and PSU correlated with worse performance in different cognitive domains; smoking status affected perfusion-cognition relationships in ALC only. Lower BREOS perfusion in both substance using groups related to higher impulsivity.

CONCLUSION

Although regional perfusion was not decreased in PSU as a group, the combination of cigarette smoking and polysubstance use is strongly related to hypoperfusion in important cortical and subcortical regions. As lower perfusion relates to greater smoking severity, worse cognition and higher impulsivity, smoking cessation is warranted for treatment-seeking PSU and ALC.

Alcohol decreases baseline brain glucose metabolism more in heavy drinkers than controls but has no effect on stimulation-induced metabolic increases

During alcohol intoxication, the human brain increases metabolism of acetate and decreases metabolism of glucose as energy substrate. Here we hypothesized that chronic heavy drinking facilitates this energy substrate shift both for baseline and stimulation conditions. To test this hypothesis, we compared the effects of alcohol intoxication (0.75 g/kg alcohol vs placebo) on brain glucose metabolism during video stimulation (VS) versus when given with no stimulation (NS), in 25 heavy drinkers (HDs) and 23 healthy controls, each of whom underwent four PET-(18)FDG scans. We showed that resting whole-brain glucose metabolism (placebo-NS) was lower in HD than controls (13%, p = 0.04); that alcohol (compared with placebo) decreased metabolism more in HD (20 ± 13%) than controls (9 ± 11%, p = 0.005) and in proportion to daily alcohol consumption (r = 0.36, p = 0.01) but found that alcohol did not reduce the metabolic increases in visual cortex from VS in either group. Instead, VS reduced alcohol-induced decreases in whole-brain glucose metabolism (10 ± 12%) compared with NS in both groups (15 ± 13%, p = 0.04), consistent with stimulation-related glucose metabolism enhancement. These findings corroborate our hypothesis that heavy alcohol consumption facilitates use of alternative energy substrates (i.e., acetate) for resting activity during intoxication, which might persist through early sobriety, but indicate that glucose is still favored as energy substrate during brain stimulation. Our findings are consistent with reduced reliance on glucose as the main energy substrate for resting brain metabolism during intoxication (presumably shifting to acetate or other ketones) and a priming of this shift in HDs, which might make them vulnerable to energy deficits during withdrawal.

Cognitive control in alcohol use disorder: deficits and clinical relevance

Cognitive control refers to the internal representation, maintenance, and updating of context information in the service of exerting control over thoughts and behavior. Deficits in cognitive control likely contribute to difficulty in maintaining abstinence in individuals with alcohol use disorders (AUD). In this article, we define three cognitive control processes in detail (response inhibition, distractor interference control, and working memory), review the tasks measuring performance in these areas, and summarize the brain networks involved in carrying out these processes. Next, we review evidence of deficits in these processes in AUD, including both metrics of task performance and functional neuroimaging. Finally, we explore the clinical relevance of these deficits by identifying predictors of clinical outcome and markers that appear to change (improve) with treatment. We observe that individuals with AUD experience deficits in some, but not all, metrics of cognitive control. Deficits in cognitive control may predict clinical outcome in AUD, but more work is necessary to replicate findings. It is likely that performance on tasks requiring cognitive control improves with abstinence, and with some psychosocial and medication treatments. Future work should clarify which aspects of cognitive control are most important to target during treatment of AUD.

Residual symptoms and functional performance in a large sample of euthymic bipolar patients in France (the OPTHYMUM study)

BACKGROUND

Some residual symptoms were found to be associated with impaired functioning in euthymic bipolar patients, but their impact and relevance are unclear in clinical practice. We re-examined the functional influence of a large set of residual symptoms in 525 euthymic bipolar outpatients using self- and clinician-rated questionnaires (OPTHYMUM study).

METHODS

This was a multi-centre, cross-sectional, non-interventional study of adult bipolar outpatients. All patients were euthymic at the time of assessment (YMRS score <8 and BDRS ≤8). Patients with low functioning (GAF score <60) were compared with the rest of the sample. Patients filled in specific questionnaires concerning their perceptions of different residual and subsyndromal symptoms.

RESULTS

Ninety-seven (97) psychiatrists included 525 patients. Of them, 35 patients had a GAF score <60. These "low functioning patients" were more frequently unemployed, had presented more manic episodes and psychotic symptoms, used more atypical antipsychotics or benzodiazepines and received less adjunctive psychotherapy. Concerning residual symptoms, they had more frequent emotional subsyndromal symptoms, disruption of circadian rhythms and sexual disorders. They perceived some cognitive deficits and suffered more social and family stigma.

LIMITATIONS

Our study used an arbitrary GAF cut-off score (60) to separate bipolar patients in two groups (low and satisfactory functioning).

CONCLUSIONS

Residual symptoms are associated with functional impairment and may represent specific treatment targets. A personalized approach through specific psychotherapeutic programs may lead to more efficient support by the clinician.

Mediated and moderated effects of neurocognitive impairment on outcomes of treatment for substance dependence and major depression

OBJECTIVE

Neurocognitive impairment has not consistently predicted substance use treatment outcomes but has been linked to proximal mediators of outcome. These indirect effects have not been examined in adults with substance dependence and co-occurring psychiatric disorders. We examined mediators and moderators of the effects of neurocognitive impairment on substance use among adults in treatment for alcohol or drug dependence and major depression (MDD).

METHOD

Participants were veterans (N = 197, mean age = 49.3 years, 90% male, 75% Caucasian) in a trial of 2 group interventions for alcohol/drug dependence and MDD. Measures examined here included intake neurocognitive assessments and percent days drinking (PDD), percent days using drugs (PDDRG), self-efficacy, 12-step affiliation, and depressive symptoms measured every 3 months from intake to the 18-month follow-up.

RESULTS

Greater intake neurocognitive impairment predicted lower self-efficacy, lower 12-step affiliation, and greater depression severity, and these time-varying variables mediated the effects of impairment on future PDD and PDDRG. The prospective effects of 12-step affiliation on future PDD were greater for those with greater neurocognitive impairment. Impairment also interacted with depression to moderate the effects of 12-step affiliation and self-efficacy on PDD. Adults with greater impairment and currently severe depression had the strongest associations between 12-step affiliation/self-efficacy and future drinking.

CONCLUSIONS

Greater neurocognitive impairment may lead to poorer outcomes from group therapy for alcohol/drug dependence and MDD due to compromised change in therapeutic processes. Distal factors such as neurocognitive impairment can interact with dynamic risk factors to modulate the association between therapeutic processes and future drinking outcomes.

CNS proteomes in alcohol and drug abuse and dependence

Drugs of abuse, including alcohol, can induce dependency formation and/or brain damage in brain regions important for cognition. 'High-throughput' approaches, such as cDNA microarray and proteomics, allow the analysis of global expression profiles of genes and proteins. These technologies have recently been applied to human brain tissue from patients with psychiatric illnesses, including substance abuse/dependence and appropriate animal models to help understand the causes and secondary effects of these complex disorders. Although these types of studies have been limited in number and by proteomics techniques that are still in their infancy, several interesting hypotheses have been proposed. Focusing on CNS proteomics, we aim to review and update current knowledge in this rapidly advancing area.

Convergence and divergence of neuroanatomic correlates and executive task performance in healthy controls and psychiatric participants

The associations between brain matter volume in the cerebral cortex and set shifting and attentional control as operationalized by the Wisconsin Card Sort Test (WCST) and Condition Three of the Delis-Kaplan version of the Color Word Interference Test (CWIT) were investigated in 15 healthy controls and 16 heterogeneously diagnosed psychiatric patients with self-control problems using voxel based morphometry. Both groups underwent standardized magnetic resonance imaging and neuropsychological assessment. WCST and CWIT variables, and a composite, were regressed across the whole brain. Although CWIT performance levels were the same in both groups, neuroanatomic correlates for the psychiatric participants invoked the left hemisphere language system, but the bilateral dorsal attention system in the healthy controls. On its own, no neuroanatomic correlates were observed for the WCST. But when part of a composite with CWIT, neuroanatomic correlates in the dorsal attention system emerged for the psychiatric participants. Psychometric combinations of manifest executive task variables may best represent higher level latent neuro-cognitive control systems. Factor analytic studies of neuropsychological test performances suggest the constructs being measured are the same across psychiatric and non-diagnosed participants, however, imaging modalities indicate the relevant neural architecture can vary by group.

A selective insular perfusion deficit contributes to compromised salience network connectivity in recovering alcoholic men

BACKGROUND

Alcoholism can disrupt neural synchrony between nodes of intrinsic functional networks that are maximally active when resting relative to engaging in a task, the default mode network (DMN) pattern. Untested, however, are whether the DMN in alcoholics can rebound normally from the relatively depressed task state to the active resting state and whether local perfusion deficits could disrupt network synchrony when switching from conditions of rest to task to rest, thereby indicating a physiological mechanism of neural network adaptation capability.

METHODS

Whole-brain, three-dimensional pulsed-continuous arterial spin labeling provided measurements of regional cerebral blood flow (CBF) in 12 alcoholics and 12 control subjects under three conditions: pretask rest, spatial working-memory task, and posttask rest.

RESULTS

With practice, alcoholics and control subjects achieved similar task accuracy and reaction times. Both groups exhibited a high-low-high pattern of perfusion levels in DMN regions during the rest-task-rest runs and the opposite pattern in posterior and cerebellar regions known to be associated with spatial working memory. Alcoholics showed selective differences from control subjects in the rest-task-rest CBF pattern in the anterior precuneus and CBF level in the insula, a hub of the salience network. Connectivity analysis identified activation synchrony from an insula seed to salience nodes (parietal, medial frontal, anterior cingulate cortices) in control subjects only.

CONCLUSIONS

We propose that attenuated insular CBF is a mechanism underlying compromised connectivity among salience network nodes. This local perfusion deficit in alcoholics has the potential to impair ability to switch from cognitive states of interoceptive cravings to cognitive control for curbing internal urges.

Psychosocial predictors of impulsivity in alcohol-dependent patients

Impulsivity is an important risk factor of severe course of alcohol dependence. However, the significance of environmental determinants of impulsivity has been underestimated. The aim of this study was to identify psychosocial factors increasing the level of impulsivity in alcoholics. Levels of impulsivity were measured in 304 alcohol-dependent patients. The stop-signal task was used to assess behavioral impulsivity, and the Barratt Impulsiveness Scale, to measure global and cognitive impulsivity. Correlations between impulsivity and psychosocial variables were examined. A significant association between level of impulsivity and severity of psychopathological symptoms was observed. Patients who reported childhood sexual or physical abuse, lower social support, and more severe course of alcohol dependence were more impulsive, especially in the cognitive domain. When entered into a linear regression analysis model, severity of alcohol dependence, psychopathology, and childhood physical abuse remained significant. These results suggest that psychosocial variables are important factors associated with high levels of impulsivity in alcohol-dependent patients.

Greater executive and visual memory dysfunction in comorbid bipolar disorder and substance use disorder

Measures of cognitive dysfunction in Bipolar Disorder (BD) have identified state and trait dependent metrics. An influence of substance abuse (SUD) on BD has been suggested. This study investigates potential differential, additive, or interactive cognitive dysfunction in bipolar patients with or without a history of SUD. Two hundred fifty-six individuals with BD, 98 without SUD and 158 with SUD, and 97 Healthy Controls (HC) completed diagnostic interviews, neuropsychological testing, and symptom severity scales. The BD groups exhibited poorer performance than the HC group on most cognitive factors. The BD with SUD exhibited significantly poorer performance than BD without SUD in visual memory and conceptual reasoning/set-shifting. In addition, a significant interaction effect between substance use and depressive symptoms was found for auditory memory and emotion processing. BD patients with a history of SUD demonstrated worse visual memory and conceptual reasoning skills above and beyond the dysfunction observed in these domains among individuals with BD without SUD, suggesting greater impact on integrative, gestalt-driven processing domains. Future research might address longitudinal outcome as a function of BD, SUD, and combined BD/SUD to evaluate neural systems involved in risk for, and effects of, these illnesses.

Neural correlates of hot and cold executive functions in polysubstance addiction: association between neuropsychological performance and resting brain metabolism as measured by positron emission tomography

The study of substance-abuse-related neuropsychological deficits and brain alterations may provide a better understanding of the neuroadaptations associated with addiction. In this study we investigated the association between performance on neuropsychological tests of cold and hot executive functions and regional brain metabolism. Measured with positron emission tomography (PET), in a sample of 49 substance-dependent individuals (SDI). Neuropsychological performance in the SDI group was compared to that of a non-drug-using control group of 30 participants, and associated with two sets of PET-derived dependent measures: one based on regions of interest (examining mean uptake in selected regions), and a second based on voxel uptake measures (using Statistical Parametric Mapping voxel-based whole-brain analyses). Behavioral analyses showed that SDI had poorer performance than controls across executive function and emotion processing measures. Regression models showed that SDI's performance in "cold" executive tests (i.e., updating, inhibition and flexibility) was associated with regional metabolism in the dorsolateral prefrontal cortex (DLPFC), mid-superior frontal gyrus, superior and inferior temporal gyrus and inferior parietal cortex, whereas performance in "hot" executive functions (i.e., self-regulation, decision-making and emotion perception) was associated with DLPFC, mid-superior frontal gyrus, anterior and mid-posterior cingulate, and temporal and fusiform gyrus. These results are discussed in terms of their relevance for the understanding of cognitive dysfunction and neuroadaptations linked to addiction.

Function and dysfunction of prefrontal brain circuitry in alcoholic Korsakoff's syndrome

The signature symptom of alcohol-induced persisting amnestic disorder, more commonly referred to as alcoholic Korsakoff's syndrome (KS), is anterograde amnesia, or memory loss for recent events, and until the mid 20th Century, the putative brain damage was considered to be in diencephalic and medial temporal lobe structures. Overall intelligence, as measured by standardized IQ tests, usually remains intact. Preservation of IQ occurs because memories formed before the onset of prolonged heavy drinking--the types of information and abilities tapped by intelligence tests--remain relatively well preserved compared with memories recently acquired. However, clinical and experimental evidence has shown that neurobehavioral dysfunction in alcoholic patients with KS does include nonmnemonic abilities, and further brain damage involves extensive frontal and limbic circuitries. Among the abnormalities are confabulation, disruption of elements of executive functioning and cognitive control, and emotional impairments. Here, we discuss the relationship between neurobehavioral impairments in KS and alcoholism-related brain damage. More specifically, we examine the role of damage to prefrontal brain systems in the neuropsychological profile of alcoholic KS.

Effects of Alcohol Intoxication on Response Conflict in a Flanker Task

Events evoke seamlessly integrated stimulus evaluation and response preparation processing streams, guided by regulative functions that change behavior flexibly in accord with the internal goals and contextual demands. The neural basis of the effects of alcohol intoxication on these processing streams is poorly understood, despite the evidence of alcohol's deleterious effects on both attention and motor control. In an attempt to separate and examine relative susceptibility of these two dimensions, we employed a color version of the Eriksen flanker task that manipulated compatibility at the stimulus- and response-processing levels. Functional magnetic resonance imaging (fMRI) was performed in healthy social drinkers as they participated in both alcohol (0.6 g/kg ethanol for men, 0.55 g/kg for women) and placebo conditions in a counterbalanced design. Alcohol increased reaction times to response-level incongruity and decreased accuracy overall. Relative to the no-conflict condition, the observed brain activity was predominantly evoked by response-related conflict in medial prefrontal and lateral prefrontal cortices under placebo, in agreement with extensive evidence of their role in conflict processing. Activity evoked by response incongruity in the medial frontal cortex and insula was insignificant under alcohol, indicating its interference with response inhibition and preparation. Conversely, activity in ventrolateral prefrontal and premotor areas was relatively greater under alcohol than placebo, suggesting their compensatory engagement. This finding is consistent with the compensatory prefrontal activity increase found in studies with chronic alcoholic individuals, indicating functional reorganization with a goal of optimizing response strategy. These results delineate functional differences and selective susceptibility of a prefrontal network subserving response-level conflict processing. Our findings are incompatible with notions that moderate alcohol primarily affects attentional or stimulus-related processing and argue instead that its primary influence is on response inhibition, selection, and execution, with ramifications for the models of behavioral self-control and the inability to refrain from drinking.

Event-Related Oscillations in Alcoholism Research: A Review

Alcohol dependence is characterized as a multi-factorial disorder caused by a complex interaction between genetic and environmental liabilities across development. A variety of neurocognitive deficits/dysfunctions involving impairments in different brain regions and/or neural circuitries have been associated with chronic alcoholism, as well as with a predisposition to develop alcoholism. Several neurobiological and neurobehavioral approaches and methods of analyses have been used to understand the nature of these neurocognitive impairments/deficits in alcoholism. In the present review, we have examined relatively novel methods of analyses of the brain signals that are collectively referred to as event-related oscillations (EROs) and show promise to further our understanding of human brain dynamics while performing various tasks. These new measures of dynamic brain processes have exquisite temporal resolution and allow the study of neural networks underlying responses to sensory and cognitive events, thus providing a closer link to the physiology underlying them. Here, we have reviewed EROs in the study of alcoholism, their usefulness in understanding dynamical brain functions/dysfunctions associated with alcoholism as well as their utility as effective endophenotypes to identify and understand genes associated with both brain oscillations and alcoholism.

Neurocognitive deficits in male alcoholics: an ERP/sLORETA analysis of the N2 component in an equal probability Go/NoGo task

In alcoholism research, studies concerning time-locked electrophysiological aspects of response inhibition have concentrated mainly on the P3 component of the event-related potential (ERP). The objective of the present study was to investigate the N2 component of the ERP to elucidate possible brain dysfunction related to the motor response and its inhibition using a Go/NoGo task in alcoholics. The sample consisted of 78 abstinent alcoholic males and 58 healthy male controls. The N2 peak was compared across group and task conditions. Alcoholics showed significantly reduced N2 peak amplitudes compared to normal controls for Go as well as NoGo task conditions. Control subjects showed significantly larger NoGo than Go N2 amplitudes at frontal regions, whereas alcoholics did not show any differences between task conditions at frontal regions. Standardized low resolution electromagnetic tomography analysis (sLORETA) indicated that alcoholics had significantly lower current density at the source than control subjects for the NoGo condition at bilateral anterior prefrontal regions, whereas the differences between groups during the Go trials were not statistically significant. Furthermore, NoGo current density across both groups revealed significantly more activation in bilateral anterior cingulate cortical (ACC) areas, with the maximum activation in the right cingulate regions. However, the magnitude of this difference was much less in alcoholics compared to control subjects. These findings suggest that alcoholics may have deficits in effortful processing during the motor response and its inhibition, suggestive of possible frontal lobe dysfunction.

What have positron emission tomography and 'Zippy' told us about the neuropharmacology of drug addiction?

Translational molecular imaging with positron emission tomography (PET) and allied technologies offer unrivalled applications in the discovery of biomarkers and aetiological mechanisms relevant to human disease. Foremost among clinical PET findings during the past two decades of addiction research is the seminal discovery of reduced dopamine D(2/3) receptor expression in the striatum of drug addicts, which could indicate a predisposing factor and/or compensatory reaction to the chronic abuse of stimulant drugs. In parallel, recent years have witnessed significant improvements in the performance of small animal tomographs (microPET) and a refinement of animal models of addiction based on clinically relevant diagnostic criteria. This review surveys the utility of PET in the elucidation of neuropharmacological mechanisms underlying drug addiction. It considers the consequences of chronic drug exposure on regional brain metabolism and neurotransmitter function and identifies those areas where further research is needed, especially concerning the implementation of PET tracers targeting neurotransmitter systems other than dopamine, which increasingly have been implicated in the pathophysiology of drug addiction. In addition, this review considers the causal effects of behavioural traits such as impulsivity and novelty/sensation-seeking on the emergence of compulsive drug-taking. Previous research indicates that spontaneously high-impulsive rats--as exemplified by 'Zippy'--are pre-disposed to escalate intravenous cocaine self-administration, and subsequently to develop compulsive drug taking tendencies that endure despite concurrent adverse consequences of such behaviour, just as in human addiction. The discovery using microPET of pre-existing differences in dopamine D(2/3) receptor expression in the striatum of high-impulsive rats suggests a neural endophenotype that may likewise pre-dispose to stimulant addiction in humans.

Alcohol and the human brain: a systematic review of different neuroimaging methods

BACKGROUND

Imaging techniques have been in widespread use in the scientific community for more than 3 decades. They facilitate noninvasive, in vivo studies of the human brain in both healthy and diseased persons. These brain-imaging techniques have contributed significantly to our understanding of the effects of alcohol abuse and dependence on structural and functional changes in the human brain. A systematic review summarizing these contributions has not previously been conducted, and this is the goal of the current paper.

METHODS

The databases PubMed, PsycINFO, and PSYNDEX were searched using central key words. Fulfilling the inclusion criteria were 140 functional and structural imaging studies, together comprising data from more than 7,000 patients and controls. The structural imaging techniques we considered were cranial computerized tomography and various magnetic resonance imaging-based techniques, including voxel-based morphometry, deformation-based morphometry, diffusion tensor magnetic resonance imaging, and diffusion-weighted magnetic resonance imaging. The functional methods considered were magnetic resonance spectroscopy, positron emission tomography, single photon emission computed tomography, and functional magnetic resonance imaging.

RESULTS

Results from studies using structural imaging techniques have revealed that chronic alcohol use is accompanied by volume reductions of gray and white matter, as well as microstructural disruption of various white matter tracts. These changes are partially reversible following abstinence. Results from functional imaging methods have revealed metabolic changes in the brain, lower glucose metabolism, and disruptions of the balance of neurotransmitter systems. Additionally, functional imaging methods have revealed increased brain activity in the mesocorticolimbic system in response to alcohol-themed pictures relative to nondrug-associated stimuli, which might be of predictive value with regard to relapse.

CONCLUSIONS

There has been tremendous progress in the development of imaging technologies. Use of these technologies has clearly demonstrated the structural and functional brain abnormalities that can occur with chronic alcohol use. The study of the alcoholic brain provides an heuristic model which furthers our understanding of neurodegenerative changes in general, as well as their partial reversibility with sustained abstinence. Additionally, functional imaging is poised to become an important tool for generating predictions about individual brain functioning, which can then be used as a basis for personalized medicine.

Effects of acamprosate on cognition in a treatment study of patients with schizophrenia spectrum disorders and comorbid alcohol dependence

Problems with memory and attention are common to both schizophrenia and alcohol dependence. The objectives of this study were to examine the effect of acamprosate treatment on cognition and to assess whether the changes in drinking patterns or psychotic symptoms were related to changes in cognitive functioning. Outpatients with schizophrenia spectrum disorders and alcohol dependence (n = 23) were randomized (double-blind) to either acamprosate or placebo treatment for 12 weeks. Assessments (baseline and week 12) included alcohol use, symptoms of psychosis, memory, and attention. The results showed that acamprosate had no effect on cognitive functioning and that there was no relationship between change in alcohol consumption or psychotic symptoms and change in cognitive functioning in this sample of patients. The finding that acamprosate had no negative effects on cognition is clinically relevant and reinforces previous reports that acamprosate can be used safely for alcohol reduction in this group of patients.

Altered fronto-cerebellar connectivity in alcohol-naïve youth with a family history of alcoholism

Fronto-cerebellar connections are thought to be involved in higher-order cognitive functioning. It is suspected that damage to this network may contribute to cognitive deficits in chronic alcoholics. However, it remains to be elucidated if fronto-cerebellar circuitry is altered in high-risk individuals even prior to alcohol use onset. The current study used functional connectivity MRI (fcMRI) to examine fronto-cerebellar circuitry in 13 alcohol-naïve, at-risk youth with a family history of alcoholism (FH+) and 14 age-matched controls. In addition, we examined how white matter microstructure, as evidenced by fractional anisotropy (FA), related to fcMRI. FH+youth showed significantly reduced functional connectivity between bilateral anterior prefrontal cortices and contralateral cerebellar seed regions compared to controls. We found that this reduction in connectivity significantly correlated with reduced FA in the anterior limb of the internal capsule and the superior longitudinal fasciculus. Taken together, our findings reflect associated aberrant functional and structural connectivity in substance-naïve FH+adolescents, perhaps suggesting an identifiable neurophenotypic precursor to substance use. Given the role of frontal and cerebellar brain regions in subserving executive functioning, the presence of premorbid abnormalities in fronto-cerebellar circuitry may heighten the risk for developing an alcohol use disorder in FH+youth through atypical control processing.

Effects of alcohol on tests of executive functioning in men and women: a dose response examination

Alcohol has been shown to affect performance on tasks associated with executive functioning. However, studies in this area have generally been limited to a single dose or gender or have used small sample sizes. The purpose of this study was to provide a more nuanced and systematic examination of alcohol's effects on commonly used tests of executive functioning at multiple dosages in both men and women. Research volunteers (91 women and 94 men) were randomly assigned to one of four drink conditions (alcohol doses associated with target blood alcohol concentrations of .000%, .050%, .075%, and .100%). Participants then completed three tasks comprising two domains of executive functioning: two set shifting tasks, the Trail Making Test and a computerized version of the Wisconsin Card Sorting Task, and a response inhibition task, the GoStop Impulsivity Paradigm. Impaired performance on set shifting tasks was found at the .100% and .075% dosages, but alcohol intoxication did not impair performance on the GoStop. No gender effects emerged. Thus, alcohol negatively affects set shifting at moderately high levels of intoxication in both men and women, likely attributable to alcohol's interference with prefrontal cortex function. Although it is well established that alcohol negatively affects response inhibition as measured by auditory stop-signal tasks, alcohol does not appear to exert a negative effect on response inhibition as measured by the GoStop, a visual stop-signal task.

Recruitment of additional brain regions to accomplish simple motor tasks in chronic alcohol-dependent patients

BACKGROUND

Chronic alcohol-dependent patients (ALC) exhibit neurocognitive impairments attributed to alcohol-induced fronto-cerebellar damage. Deficits are typically found in complex task performance, whereas simple tasks may not be significantly compromised, perhaps because of little understood compensatory changes.

METHODS

We compared finger tapping with either hand at externally paced (EP) or maximal self-paced (SP) rates and concomitant brain activation in ten pairs of right-hand dominant, age-, and gender-matched, severe, uncomplicated ALC and normal controls (NC) using functional magnetic resonance imaging (fMRI).

RESULTS

Mean tapping rates were not significantly different in ALC and NC for either task, but SP tapping variances were greater in ALC for both hands. SP tapping was more rapid with dominant hand (DH) than non-dominant hand (NDH) for both groups. EP and SP tapping with the non-dominant hand demonstrated significantly more activation in ALC than NC in the pre and postcentral gyri, inferior frontal gyrus, inferior parietal lobule, and the middle temporal gyrus. Areas activated only by ALC (not at all by NC) during NDH tapping included the inferior frontal gyrus, middle temporal gyrus, and postcentral gyrus. There were no significant group activation differences with DH tapping. No brain regions activated more in NC than ALC. SP tapping in contrast to EP activated fronto-cerebellar networks in NC, including postcentral gyrus, anterior cingulate, and the anterior lobe and vermis of the cerebellum, but only parietal precuneus in ALC.

CONCLUSIONS

These findings with NDH finger tapping support previous reports of neurocognitive inefficiencies in ALC. Inferior frontal activation with EP in ALC, but not in NC, suggests engagement of regions needed for planning, organization, and impulse regulation; greater contralateral parietal lobe activation with SP in ALC may reflect right hemispheric impairments in visuospatial performance. Contrasting brain activation during SP and EP suggests that ALC may not have enlisted a fronto-cerebellar network as did NC but rather employed a higher order planning mode by recruiting parietal lobe functions to attain normal mean finger tapping rates. Elucidation of the compensatory neural mechanisms that allow near normal performance by ALC on simple tasks can inform functional rehabilitation of patients in recovery.

Extinction of drug- and withdrawal-paired cues in animal models: relevance to the treatment of addiction

Conditioned drug craving and withdrawal elicited by cues paired with drug use or acute withdrawal are among the many factors contributing to compulsive drug taking. Understanding how to stop these cues from having these effects is a major goal of addiction research. Extinction is a form of learning in which associations between cues and the events they predict are weakened by exposure to the cues in the absence of those events. Evidence from animal models suggests that conditioned responses to drug cues can be extinguished, although the degree to which this occurs in humans is controversial. Investigations into the neurobiological substrates of extinction of conditioned drug craving and withdrawal may facilitate the successful use of drug cue extinction within clinical contexts. While this work is still in the early stages, there are indications that extinction of drug- and withdrawal-paired cues shares neural mechanisms with extinction of conditioned fear. Using the fear extinction literature as a template, it is possible to organize the observations on drug cue extinction into a cohesive framework.

Ethanol self-administration modulation of NMDA receptor subunit and related synaptic protein mRNA expression in prefrontal cortical fields in cynomolgus monkeys

BACKGROUND

Functional impairment of the orbital and medial prefrontal cortex underlies deficits in executive control that characterize addictive disorders, including alcohol addiction. Previous studies indicate that alcohol alters glutamate neurotransmission and one substrate of these effects may be through the reconfiguration of the subunits constituting ionotropic glutamate receptor (iGluR) complexes. Glutamatergic transmission is integral to cortico-cortical and cortico-subcortical communication, and alcohol-induced changes in the abundance of the receptor subunits and/or their splice variants may result in critical functional impairments of prefrontal cortex in the alcohol-addicted state.

METHODS AND RESULTS

The effects of chronic ethanol self-administration on glutamate receptor ionotropic NMDA (GRIN), as well as GRIN1 splice variant mRNA expression was studied in the orbitofrontal cortex (OFC; Area 13), dorsolateral prefrontal cortex (DLPFC; Area 46) and anterior cingulate cortex (ACC; Area 24) of male cynomolgus monkeys. Chronic ethanol self-administration resulted in significant changes in the expression of NMDA subunit mRNA expression in the DLPFC and OFC, but not the ACC. In DLPFC, the overall expression of NMDA subunits was significantly decreased in ethanol treated monkeys. Slight but significant changes were observed for synaptic associated protein 102 kD (SAP102) and neuronal nitric oxide synthase (nNOS) mRNAs. In OFC, the NMDAR1 variant GRIN1-1 was reduced while GRIN1-2 was increased. Furthermore, no significant changes in GFAP protein levels were observed in either the DLPFC or OFC.

CONCLUSION

Results from these studies provide the first demonstration of posttranscriptional regulation of iGluR subunits in the primate brain following long-term ethanol self-administration. Furthermore, changes in these transcripts do not appear to reflect changes in glial activation or loss. Further studies examining the expression and cellular localization of subunit proteins and receptor pharmacology would shed more light on the findings reported here.

Alcohol and the prefrontal cortex

The prefrontal cortex occupies the anterior portion of the frontal lobes and is thought to be one of the most complex anatomical and functional structures of the mammalian brain. Its major role is to integrate and interpret inputs from cortical and sub-cortical structures and use this information to develop purposeful responses that reflect both present and future circumstances. This includes both action-oriented sequences involved in obtaining rewards and inhibition of behaviors that pose undue risk or harm to the individual. Given the central role in initiating and regulating these often complex cognitive and behavioral responses, it is no surprise that alcohol has profound effects on the function of the prefrontal cortex. In this chapter, we review the basic anatomy and physiology of the prefrontal cortex and discuss what is known about the actions of alcohol on the function of this brain region. This includes a review of both the human and animal literature including information on the electrophysiological and behavioral effects that follow acute and chronic exposure to alcohol. The chapter concludes with a discussion of unanswered questions and areas needing further investigation.

Reversible alcohol-related dementia: a five-year follow-up study using FDG-PET and neuropsychological tests

OBJECTIVE

As the pathophysiology of alcohol-related dementia (ARD) is unclear, we examined a patient with reversible ARD using neuropsychological tests and (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET).

DESIGN

A five-year follow-up case study with neuropsychological tests and FDG-PET.

SETTING

Kyoto University Hospital. Patients A 42-year-old patient who was unable to perform his office duties because of slowly progressive amnesia with executive dysfunction.

RESULTS

The initial evaluation with neuropsychological tests showed severe verbal memory disturbance. The patient did not discuss his excessive alcohol consumption in the initial history-taking session and thiamine deficiency was absent; therefore, early-stage Alzheimer's disease was suspected. Later, the patient revealed prior excessive alcohol intake and his cognitive function improved markedly after a period of abstinence. Retrospective analysis of initial FDG-PET images using a voxel-wise statistical method revealed glucose hypometabolism in the diencephalon and basal forebrain. Follow-up for 5 years after the initial evaluation showed improved cognitive function and recovery of glucose metabolism in the two brain regions.

CONCLUSION

Hypofunction in the diencephalon and basal forebrain was associated with cognitive decline in our patient. This case may provide evidence for the etiopathic brain regions in reversible type ARD.

A history of alcohol dependence increases the incidence and severity of postoperative cognitive dysfunction in cardiac surgical patients

Postoperative cognitive dysfunction (POCD) commonly occurs after cardiac surgery. We tested the hypothesis that a history of alcohol dependence is associated with an increased incidence and severity of POCD in male patients undergoing cardiac surgery using cardiopulmonary bypass. Recent verbal and nonverbal memory and executive functions were assessed before and one week after surgery in patients with or without a history of alcohol dependence. Cognitive function was significantly reduced after cardiac surgery in patients with versus without a history of alcohol dependence. The results suggest that a history of alcohol dependence increases the incidence and severity of POCD after cardiac surgery.

Executive control deficits in substance-dependent individuals: a comparison of alcohol, cocaine, and methamphetamine and of men and women

Substance dependence is associated with executive function deficits, but the nature of these executive defects and the effect that different drugs and sex have on these defects have not been fully clarified. Therefore, we compared the performance of alcohol- (n = 33; 18 women), cocaine- (n = 27; 14 women), and methamphetamine-dependent individuals (n = 38; 25 women) with sex-matched healthy comparisons (n = 36; 17 women) on complex decision making as measured with the Iowa Gambling Task, working memory, cognitive flexibility, and response inhibition. Cocaine- and methamphetamine-dependent individuals were impaired on complex decision making, working memory, and cognitive flexibility, but not on response inhibition. The deficits in working memory and cognitive flexibility were milder than the decision-making deficits and did not change as a function of memory load or task switching. Interestingly, decision making was significantly more impaired in women addicted to cocaine or methamphetamine than in men addicted to these drugs. Together, these findings suggest that drug of choice and sex have different effects on executive functioning, which, if replicated, may help tailor intervention.

Neuropsychological consequences of HIV and substance abuse: a literature review and implications for treatment and future research

Neuropsychological dysfunction, ranging from mild cognitive symptoms to dementia has been a consistent part of the clinical picture of HIV/AIDS. However, advances in clinical management, particularly antiretroviral (ARV) treatment, have mitigated the neuropsychological effects of HIV and revised the pattern and nature of cognitive deficits, which are observed in HIV-infected individuals. The attendant improvements in mortality and morbidity have led to a need for programs and interventions that sustain healthy behavior and prevent a resurgence of HIV transmission risk. Psychiatric risk factors, particularly substance use, which often contribute to initial acquisition of HIV, still require attention. These risk factors may also exacerbate neuropsychological dysfunction and compromise adherence to prevention recommendations and treatment. Specifically, a more complete understanding of the effects of substance abuse on the progression of HIV related cognitive decline can inform evaluation and management of HIV seropositives with concurrent substance use disorders. This review provides an overview of the neuropsychology of HIV and substance abuse and the extant research that has examined the effects of both HIV disease and substance use on neuropsychological functioning and implications for treatment and future research.

Proteomics approach in the study of the pathophysiology of alcohol-related brain damage

AIMS

Chronic, excessive drinking of alcohol can induce brain damage in the regions important for neurocognitive function. Some of the damage are permanent while some are appearantly reversible. It is our aim to understand the molecular mechanisms underlying alcohol-induced and/or related brain damage, particularly of that observed in 'medically uncomplicated' (without heptatic cirrhosis or Wernicke-Korsakoff Syndrome [WKS]) alcoholics.

METHODS

A high-throughput proteomics technology has been applied to several 'alcohol-sensitive' brain regions from uncomplicated and hepatic cirrhosis-complicated alcoholics to understand the mechanisms of alcohol-related brain damage at the level of protein expression.

RESULTS

It was clearly demonstrated that each brain region reacts in significantly different manner to chronic alcohol ingestion. Appearant abnormalities in vitamin B1 (thiamine)-related biochemical pathways were observed in several brain regions, such as the dorsolateral prefrontal cortex, genu (a frontal part of the corpus callosum) and cerebellar vermis in uncomplicated alcoholics, suggesting that the reduction of this important nutritional component might be associated with brain damage even without the signs of WKS. In addition, in the two different subregions of the corpus callosum (genu and splenium [a posterior part of the corpus callosum]) and the cerebellar vermis, significant differences in protein expression profiles between uncomplicated and complicated alcoholics with hepatic cirrhosis were identified, suggesting that hepatic factors such as ammonia have significant additive influences on brain protein expression, which might lead to the structural changes and/or damage in these brain regions. Furthermore, in the hippocampus, significant change of the level of glutamine synthetase expression was observed, suggesting once again the importance of ammonia as a cause of brain damage in this region.

CONCLUSIONS

Although our data did not show any evidence of "direct" alcohol effects to induce the alteration of protein expression in association with brain damage, high-throughput neuroproteomics approaches are proven to have a potential to dissect the mechanisms of complex brain disorders.

Effects of alcoholism severity and smoking on executive neurocognitive function

AIMS

Neurocognitive deficits in chronic alcoholic men are well documented. Impairments include memory, visual-spatial processing, problem solving and executive function. The cause of impairment could include direct effects of alcohol toxicity, pre-existing cognitive deficits that predispose towards substance abuse, comorbid psychiatric disorders and abuse of substances other than alcohol. Cigarette smoking occurs at higher rates in alcoholism and has been linked to poor cognitive performance, yet the effects of smoking on cognitive function in alcoholism are often ignored. We examined whether chronic alcoholism and chronic smoking have effects on executive function.

METHODS

Alcoholism and smoking were examined in a community-recruited sample of alcoholic and non-alcoholic men (n = 240) using standard neuropsychological and reaction-time measures of executive function. Alcoholism was measured as the average level of alcoholism diagnoses across the study duration (12 years). Smoking was measured in pack-years.

RESULTS

Both alcoholism and smoking were correlated negatively with a composite executive function score. For component measures, alcoholism was correlated negatively with a broad range of measures, whereas smoking was correlated negatively with measures that emphasize response speed. In regression analyses, both smoking and alcoholism were significant predictors of executive function composite. However, when IQ is included in the regression analyses, alcoholism severity is no longer significant.

CONCLUSIONS

Both smoking and alcoholism were related to executive function. However, the effect of alcoholism was not independent of IQ, suggesting a generalized effect, perhaps affecting a wide range of cognitive abilities of which executive function is a component. On the other hand, the effect of smoking on measures relying on response speed were independent of IQ, suggesting a more specific processing speed deficit associated with chronic smoking.