Neuronal loss in functional zones of the cerebellum of chronic alcoholics with and without Wernicke's encephalopathy

Axonal pathology differentially affects human Purkinje cell subtypes in the essential tremor cerebellum

The cerebellar cortex is organized into discrete regions populated by molecularly distinct Purkinje cells (PCs), the sole cortical output neurons. While studies in animal models have shown that PC subtypes differ in their vulnerability to disease, our understanding of human PC subtype and vulnerability remains limited. Here, we demonstrate that human cerebellar regions specialized for motor vs cognitive functions (lobule HV vs Crus I) contain distinct PC populations characterized by specific molecular and anatomical features, which show selective vulnerability in essential tremor (ET), a cerebellar degenerative disorder. Using a known PC subtype marker, neurofilament heavy chain (NEFH), we found that motor lobule HV contains PCs with high NEFH expression, while cognitive lobule Crus I contains PCs with low NEFH expression in post-mortem samples from healthy controls. In the same cerebella, PC axons in lobule HV were 2.2-fold thicker than those in Crus I. Across lobules, axon caliber positively correlated with NEFH expression. In ET cerebella, we identified motor lobule-specific PC axon pathology with a 1.5-fold reduction in caliber and increased axon variability in lobule HV, while Crus I axons were unaffected. Tremor severity and duration in ET correlated with axon diameter variability selectively in lobule HV PCs. Given that axonal caliber is a major determinant of neural signaling capacity, our results (1) suggest that disrupted cerebellar corticonuclear signaling is occurring in ET, (2) provide evidence of region-specific PC subtypes in the human cerebellum and offer insight into how selective PC vulnerability may contribute to the pathophysiology of cerebellar degeneration.

Neuropathology of deaths due to acute alcohol toxicity in Australia, 2011-2022

BACKGROUND

A major alcohol-related harm is structural pathology affecting the brain. The study aimed to: 1. Determine the frequency and nature of neuropathology amongst cases of death due to acute alcohol toxicity; 2. Compare diagnoses of brain atrophy with pathology in other organs; 3. Determine the demographic, clinical and organ pathology correlates of brain atrophy.

METHODS

Retrospective study of 500 cases of death attributed to acute alcohol toxicity in Australia, 2011-2022. Data on clinical characteristics, toxicology, neuropathology and other organ pathology were retrieved from police reports, autopsies, toxicology and coronial findings.

RESULTS

Mean age was 49.5 years, 69.4 % were male, with alcohol use problems documented in 70.2 %. Brain atrophy was diagnosed in 60 cases (12.0 %), most commonly in the cerebellum (32 cases, 6.4 %). Atrophy at other sites was present in 37 (7.4 %). The presence of brain atrophy was lower than other major pathologies: cardiomegaly (32.6 %, p<.001), nephro/arteriosclerosis (30.2 %, p<.001), and chronic obstructive pulmonary disease (21.8 %, p<.001) but not hepatic cirrhosis (11.9 % p=1.0). Those diagnosed with atrophy were older (53.4v 49.0 years, p<.001), more likely to have documented alcohol problems (85.0v 68.2 %, Odds ratio: OR 2.53) and seizure history (10.0v 3.0 %, OR 2.92), to have cardiomegaly (43.3v 31.0 %, OR 1.90, COPD (48.3v 18.2 %, 3.57) and nephro/arteriosclerosis (50.0 v 27.4 %, OR 2.27).

CONCLUSIONS

Despite the majority of cases having a history of alcohol problems, the level of neuropathology amongst cases of death due to acute alcohol toxicity was comparatively low.

Neuropsychiatric and Neuropsychological Aspects of Alcohol-Related Cognitive Disorders: An In-Depth Review of Wernicke's Encephalopathy and Korsakoff's Syndrome

Alcohol-related cognitive disorders have long been an area of study, yet they continue to pose challenges in the diagnosis, treatment, and understanding of underlying neuropsychiatric mechanisms. The present article offers a comprehensive review of Wernicke's Encephalopathy and Korsakoff's Syndrome, two conditions often seen on a continuum of alcohol-related brain damage. Drawing on current medical literature, neuroimaging studies, and clinical case reports, we explore the neuropsychiatric and neuropsychological profiles, symptomatology, and differential diagnoses of these disorders. We delve into the biochemical pathways implicated in the development of WE and KS, notably thiamine deficiency and its impact on neurotransmitter systems and neural networks. The article also addresses the challenges in early diagnosis, often complicated by non-specific symptoms and co-occurring psychiatric conditions. Furthermore, we review the current state of treatment protocols, including pharmacological and non-pharmacological interventions. Finally, the article highlights gaps in current knowledge and suggests directions for future research to improve diagnosis, treatment, and patient outcomes. Understanding the nuanced interplay between the neuropsychiatric and neuropsychological aspects of WE and KS is crucial for both clinicians and researchers alike, in order to provide effective treatment and to advance our understanding of these complex conditions.

Alcohol Withdrawal and the Associated Mood Disorders-A Review

Recreational use of alcohol is a social norm in many communities worldwide. Alcohol use in moderation brings pleasure and may protect the cardiovascular system. However, excessive alcohol consumption or alcohol abuse are detrimental to one's health. Three million deaths due to excessive alcohol consumption were reported by the World Health Organization. Emerging evidence also revealed the danger of moderate consumption, which includes the increased risk to cancer. Alcohol abuse and periods of withdrawal have been linked to depression and anxiety. Here, we present the effects of alcohol consumption (acute and chronic) on important brain structures-the frontal lobe, the temporal lobe, the limbic system, and the cerebellum. Apart from this, we also present the link between alcohol abuse and withdrawal and mood disorders in this review, thus drawing a link to oxidative stress. In addition, we also discuss the positive impacts of some pharmacotherapies used. Due to the ever-rising demands of life, the cycle between alcohol abuse, withdrawal, and mood disorders may be a never-ending cycle of destruction. Hence, through this review, we hope that we can emphasise the importance and urgency of managing this issue with the appropriate approaches.

Uncovering the genetic profiles underlying the intrinsic organization of the human cerebellum

The functional diversity of the human cerebellum is largely believed to be derived more from its extensive connections rather than being limited to its mostly invariant architecture. However, whether and how the determination of cerebellar connections in its intrinsic organization interact with microscale gene expression is still unknown. Here we decode the genetic profiles of the cerebellar functional organization by investigating the genetic substrates simultaneously linking cerebellar functional heterogeneity and its drivers, i.e., the connections. We not only identified 443 network-specific genes but also discovered that their co-expression pattern correlated strongly with intra-cerebellar functional connectivity (FC). Ninety of these genes were also linked to the FC of cortico-cerebellar cognitive-limbic networks. To further discover the biological functions of these genes, we performed a "virtual gene knock-out" by observing the change in the coupling between gene co-expression and FC and divided the genes into two subsets, i.e., a positive gene contribution indicator (GCI⁺) involved in cerebellar neurodevelopment and a negative gene set (GCI^-) related to neurotransmission. A more interesting finding is that GCI^- is significantly linked with the cerebellar connectivity-behavior association and many recognized brain diseases that are closely linked with the cerebellar functional abnormalities. Our results could collectively help to rethink the genetic substrates underlying the cerebellar functional organization and offer possible micro-macro interacted mechanistic interpretations of the cerebellum-involved high order functions and dysfunctions in neuropsychiatric disorders.

Persistence of cerebellar ataxia during chronic ethanol exposure is associated with epigenetic up-regulation of Fmr1 gene expression in rat cerebellum

BACKGROUND

Alcohol intoxication produces ataxia by affecting the cerebellum, which coordinates movements. Fragile X mental retardation (FMR) protein is a complex regulator of RNA and synaptic plasticity implicated in fragile X-associated tremor/ataxia syndrome, which features ataxia and increased Fmr1 mRNA expression resulting from epigenetic dysregulation of FMRP. We recently demonstrated that acute ethanol-induced ataxia is associated with increased cerebellar Fmr1 gene expression via histone modifications in rats, but it is unknown whether similar behavioral and molecular changes occur following chronic ethanol exposure. Here, we investigated the effects of chronic ethanol exposure on ataxia and epigenetically regulated changes in Fmr1 expression in the cerebellum.

METHODS

Male adult Sprague-Dawley rats were trained on the accelerating rotarod and then fed with chronic ethanol or a control Lieber-DeCarli diet while undergoing periodic behavioral testing for ataxia during ethanol exposure and withdrawal. Cerebellar tissues were analyzed for expression of the Fmr1 gene and its targets using a real-time quantitative polymerase chain reaction assay. The epigenetic regulation of Fmr1 was also investigated using a chromatin immunoprecipitation assay.

RESULTS

Ataxic behavior measured by the accelerating rotarod behavioral test developed during chronic ethanol treatment and persisted at both the 8-h and 24-h withdrawal time points compared to control diet-fed rats. In addition, chronic ethanol treatment resulted in up-regulated expression of Fmr1 mRNA and increased activating epigenetic marks H3K27 acetylation and H3K4 trimethylation at 2 sites within the Fmr1 promoter. Finally, measurement of the expression of relevant FMRP mRNA targets in the cerebellum showed that chronic ethanol up-regulated cAMP response element binding (CREB) Creb1, Psd95, Grm5, and Grin2b mRNA expression without altering Grin2a, Eaa1, or histone acetyltransferases CREB binding protein (Cbp) or p300 mRNA transcripts.

CONCLUSIONS

These results suggest that epigenetic regulation of Fmr1 and subsequent FMRP regulation of target mRNA transcripts constitute neuroadaptations in the cerebellum that may underlie the persistence of ataxic behavior during chronic ethanol exposure and withdrawal.

Mechanisms of Ethanol-Induced Cerebellar Ataxia: Underpinnings of Neuronal Death in the Cerebellum

Ethanol consumption remains a major concern at a world scale in terms of transient or irreversible neurological consequences, with motor, cognitive, or social consequences. Cerebellum is particularly vulnerable to ethanol, both during development and at the adult stage. In adults, chronic alcoholism elicits, in particular, cerebellar vermis atrophy, the anterior lobe of the cerebellum being highly vulnerable. Alcohol-dependent patients develop gait ataxia and lower limb postural tremor. Prenatal exposure to ethanol causes fetal alcohol spectrum disorder (FASD), characterized by permanent congenital disabilities in both motor and cognitive domains, including deficits in general intelligence, attention, executive function, language, memory, visual perception, and communication/social skills. Children with FASD show volume deficits in the anterior lobules related to sensorimotor functions (Lobules I, II, IV, V, and VI), and lobules related to cognitive functions (Crus II and Lobule VIIB). Various mechanisms underlie ethanol-induced cell death, with oxidative stress and endoplasmic reticulum (ER) stress being the main pro-apoptotic mechanisms in alcohol abuse and FASD. Oxidative and ER stresses are induced by thiamine deficiency, especially in alcohol abuse, and are exacerbated by neuroinflammation, particularly in fetal ethanol exposure. Furthermore, exposure to ethanol during the prenatal period interferes with neurotransmission, neurotrophic factors and retinoic acid-mediated signaling, and reduces the number of microglia, which diminishes expected cerebellar development. We highlight the spectrum of cerebellar damage induced by ethanol, emphasizing physiological-based clinical profiles and biological mechanisms leading to cell death and disorganized development.

The Intersection Between Cerebellar Ataxia and Neuropathy: a Proposed Classification and a Diagnostic Approach

Neuropathy is a common associated feature of different types of genetic or sporadic cerebellar ataxias. The pattern of peripheral nerve involvement and its associated clinical features can be an invaluable aspect for narrowing the etiologic diagnosis in the investigation of cerebellar ataxias. In this review, we discuss the differential diagnosis of the intersection between peripheral nerve and cerebellar involvement, and classify them in accordance with the predominant features. Genetics, clinical features, neuroimaging, and neurophysiologic characteristics are discussed. Furthermore, a diagnostic approach for cerebellar ataxia with neuropathy is proposed according to the different clinical characteristics. This is an Educational and Descriptive review with the aim of medical education for the approach to the patients with cerebellar ataxia and neuropathy. The diagnostic approach to the patient with cerebellar ataxia with neuropathy requires a detailed medical history, phenotyping, characterization of disease progression and family history. Neuroimaging features and the neurophysiological findings play pivotal roles in defining the diagnosis. Establishing an organized classification method for the disorders based on the clinical features may be very helpful, and could be divided as those with predominant cerebellar features, predominant neuropathic feature, or conditions with both cerebellar ataxia and neuropathy. Second, determining the mode of inheritance is critical on cerebellar ataxias: autosomal dominant and recessive cerebellar ataxias, mitochondrial or sporadic types. Third, one must carefully assess neurophysiologic findings in order to better characterize the predominant pattern of involvement: damage location, mechanism of lesion (axonal or demyelinating), motor, sensory or sensory motor compromise, large or small fibers, and autonomic system abnormalities.

High-dose thiamine strategy in Wernicke-Korsakoff syndrome and related thiamine deficiency conditions associated with alcohol use disorder

Thiamine is essential for the activity of several enzymes associated with energy metabolism in humans. Chronic alcohol use is associated with deficiency of thiamine along with other vitamins through several mechanisms. Several neuropsychiatric syndromes have been associated with thiamine deficiency in the context of alcohol use disorder including Wernicke-Korsakoff syndrome, alcoholic cerebellar syndrome, alcoholic peripheral neuropathy, and possibly, Marchiafava-Bignami syndrome. High-dose thiamine replacement is suggested for these neuropsychiatric syndromes.

Categorising a problem: alcohol and dementia

Alcoholism is a chronic relapsing disorder that can include extended periods of abstinence followed by relapse to heavy drinking. Decades of evidence have clearly shown that long-term, chronic ethanol exposure produces brain damage in humans. The article aims to review the relationship between alcohol use and dementia. Medline and Google Scholar searches were conducted for relevant articles, chapters and books published until 2019. Search terms used included alcohol consumption, alcohol-related dementia, alcohol use disorders, chronic alcoholism, dementia. Publications found through this indexed search were reviewed for further relevant references. Alcohol acts on the central nervous system via both direct and indirect effects, frequently a combination of the two. There is consensus that alcohol contributes to the acquisition of cognitive deficits in late life. However, there are doubts regarding the aetiopathogenesis, nosological status and prevalence of alcohol-related dementia and still, there is much debate over how much alcohol consumption will lead to alcohol-related dementia.

The Inferior Colliculus in Alcoholism and Beyond

Post-mortem neuropathological and in vivo neuroimaging methods have demonstrated the vulnerability of the inferior colliculus to the sequelae of thiamine deficiency as occurs in Wernicke-Korsakoff Syndrome (WKS). A rich literature in animal models ranging from mice to monkeys-including our neuroimaging studies in rats-has shown involvement of the inferior colliculi in the neural response to thiamine depletion, frequently accomplished with pyrithiamine, an inhibitor of thiamine metabolism. In uncomplicated alcoholism (i.e., absent diagnosable neurological concomitants), the literature citing involvement of the inferior colliculus is scarce, has nearly all been accomplished in preclinical models, and is predominately discussed in the context of ethanol withdrawal. Our recent work using novel, voxel-based analysis of structural Magnetic Resonance Imaging (MRI) has demonstrated significant, persistent shrinkage of the inferior colliculus using acute and chronic ethanol exposure paradigms in two strains of rats. We speculate that these consistent findings should be considered from the perspective of the inferior colliculi having a relatively high CNS metabolic rate. As such, they are especially vulnerable to hypoxic injury and may be provide a common anatomical link among a variety of disparate insults. An argument will be made that the inferior colliculi have functions, possibly related to auditory gating, necessary for awareness of the external environment. Multimodal imaging including diffusion methods to provide more accurate in vivo visualization and quantification of the inferior colliculi may clarify the roles of brain stem nuclei such as the inferior colliculi in alcoholism and other neuropathologies marked by altered metabolism.

Thiamine Deficiency Increases Intrinsic Excitability of Mouse Cerebellar Purkinje Cells

Thiamine deficiency is associated with cerebellar dysfunction; however, the consequences of thiamine deficiency on the electrophysiological properties of cerebellar Purkinje cells are poorly understood. Here, we evaluated these parameters in brain slices containing cerebellar vermis. Adult mice were maintained for 12-13 days on a thiamine-free diet coupled with daily injections of pyrithiamine, an inhibitor of thiamine phosphorylation. Morphological analysis revealed a 20% reduction in Purkinje cell and nuclear volume in thiamine-deficient animals compared to feeding-matched controls, with no reduction in cell count. Under whole-cell current clamp, thiamine-deficient Purkinje cells required significantly less current injection to fire an action potential. This reduction in rheobase was not due to a change in voltage threshold. Rather, thiamine-deficient neurons presented significantly higher input resistance specifically in the voltage range just below threshold, which increases their sensitivity to current at these critical membrane potentials. In addition, thiamine deficiency caused a significant decrease in the amplitude of the action potential afterhyperpolarization, broadened the action potential, and decreased the current threshold for depolarization block. When thiamine-deficient animals were allowed to recover for 1 week on a normal diet, rheobase, threshold, action potential half-width, and depolarization block threshold were no longer different from controls. We conclude that thiamine deficiency causes significant but reversible changes to the electrophysiology properties of Purkinje cells prior to pathological morphological alterations or cell loss. Thus, the data obtained in the present study indicate that increased excitability of Purkinje cells may represent a leading indicator of cerebellar dysfunction caused by lack of thiamine.

Accelerated aging and motor control deficits are related to regional deformation of central cerebellar white matter in alcohol use disorder

The World Health Organization estimates a 12-month prevalence rate of 8+% for an alcohol use disorder (AUD) diagnosis in people age 15 years and older in the United States and Europe, presenting significant health risks that have the potential of accelerating age-related functional decline. According to neuropathological studies, white matter systems of the cerebellum are vulnerable to chronic alcohol dependence. To pursue the effect of AUD on white matter structure and functions in vivo, this study used T1-weighted, magnetic resonance imaging (MRI) to quantify the total corpus medullare of the cerebellum and a finely grained analysis of its surface in 135 men and women with AUD (mean duration of abstinence, 248 d) and 128 age- and sex-matched control participants; subsets of these participants completed motor testing. We identified an AUD-related volume deficit and accelerated aging in the total corpus medullare. Novel deformation-based surface morphometry revealed regional shrinkage of surfaces adjacent to lobules I-V, lobule IX, and vermian lobule X. In addition, accelerated aging was detected in the regional surface areas adjacent to lobules I-V, lobule VI, lobule VIIB, and lobules VIII, IX, and X. Sex differences were not identified for any measure. For both volume-based and surface-based analyses, poorer performance in gait and balance, manual dexterity, and grip strength were linked to greater regional white matter structural deficits. Our results suggest that local deformation of the corpus medullare has the potential of identifying structurally and functionally segregated networks affected in AUD.

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.

Disturbed Cerebellar Growth Trajectories in Adolescents Who Initiate Alcohol Drinking

BACKGROUND

The cerebellum is a target of alcoholism-related brain damage in adults, yet no study has prospectively tracked deviations from normal cerebellar growth trajectories in adolescents before and after initiating drinking.

METHODS

Magnetic resonance imaging tracked developmental volume trajectories of 10 cerebellar lobule and vermis tissue constituents in 548 no/low drinking youths age 12 to 21 years at induction into this 5-site, NCANDA (National Consortium on Alcohol and NeuroDevelopment in Adolescence) study. Over the 3- to 4-year longitudinal examination yielding 2043 magnetic resonance imaging scans, 328 youths remained no/low drinkers, whereas 220 initiated substantial drinking after initial neuroimaging.

RESULTS

Normal growth trajectories derived from no/low drinkers indicated that gray matter volumes of lobules V and VI, crus II, lobule VIIB, and lobule X declined faster with age in male youths than in female youths, whereas white matter volumes in crus I and crus II and lobules VIIIA and VIIIB expanded faster in female youths than in male youths; cerebrospinal fluid volume expanded faster in most cerebellar regions of male youths than female youths. Drinkers exhibited accelerated gray matter decline in anterior lobules and vermis, accelerated vermian white matter expansion, and accelerated cerebrospinal fluid volumes expansion of anterior lobules relative to youths who remained no/low drinkers. Analyses including both alcohol and marijuana did not support an independent role for marijuana in alcohol effects on cerebellar gray matter trajectories.

CONCLUSIONS

Alcohol use-related cerebellar growth trajectory differences from normal involved anterior lobules and vermis of youths who initiated substantial drinking. These regions are commonly affected in alcohol-dependent adults, raising the possibility that cerebellar structures affected by youthful drinking may be vulnerable to age-alcohol interactions in later adulthood.

Cerebellar Morphometry and Cognition in the Context of Chronic Alcohol Consumption and Cigarette Smoking

BACKGROUND

Cerebellar atrophy (especially involving the superior-anterior cerebellar vermis) is among the most salient and clinically significant effects of chronic hazardous alcohol consumption on brain structure. Smaller cerebellar volumes are also associated with chronic cigarette smoking. The present study investigated effects of both chronic alcohol consumption and cigarette smoking on cerebellar structure and its relation to performance on select cognitive/behavioral tasks.

METHODS

Using T1-weighted Magnetic Resonance Images (MRIs), the Cerebellar Analysis Tool Kit segmented the cerebellum into bilateral hemispheres and 3 vermis parcels from 4 participant groups: smoking (s) and nonsmoking (ns) abstinent alcohol-dependent treatment seekers (ALC) and controls (CON) (i.e., sALC, nsALC, sCON, and nsCON). Cognitive and behavioral data were also obtained.

RESULTS

We found detrimental effects of chronic drinking on all cerebellar structural measures in ALC participants, with largest reductions seen in vermis areas. Furthermore, both smoking groups had smaller volumes of cerebellar hemispheres but not vermis areas compared to their nonsmoking counterparts. In exploratory analyses, smaller cerebellar volumes were related to lower measures of intelligence. In sCON, but not sALC, greater smoking severity was related to smaller cerebellar volume and smaller superior-anterior vermis area. In sALC, greater abstinence duration was associated with larger cerebellar and superior-anterior vermis areas, suggesting some recovery with abstinence.

CONCLUSIONS

Our results show that both smoking and alcohol status are associated with smaller cerebellar structural measurements, with vermal areas more vulnerable to chronic alcohol consumption and less affected by chronic smoking. These morphometric cerebellar deficits were also associated with lower intelligence and related to duration of abstinence in sALC only.

Chronic voluntary alcohol consumption causes persistent cognitive deficits and cortical cell loss in a rodent model

Chronic alcohol use is associated with cognitive decline that impedes behavioral change during rehabilitation. Despite this, addiction therapy does not address cognitive deficits, and there is poor understanding regarding the mechanisms that underlie this decline. We established a rodent model of chronic voluntary alcohol use to measure ensuing cognitive effects and underlying pathology. Rats had intermittent access to alcohol or an isocaloric solution in their home cage under voluntary 2-bottle choice conditions. In Experiments 1 and 2 cognition was assessed using operant touchscreen chambers. We examined performance in a visual discrimination and reversal task (Experiment 1), and a 5-choice serial reaction time task (Experiment 2). For Experiment 3, rats were perfused immediately after cessation of alcohol access period, and volume, cell density and microglial populations were assessed in the prefrontal cortex and striatum. Volume was assessed using the Cavalieri probe, while cell and microglial counts were estimated using unbiased stereology with an optical fractionator. Alcohol-exposed and control rats showed comparable acquisition of pairwise discrimination; however, performance was impaired when contingencies were reversed indicating reduced behavioral flexibility. When tested in a 5-choice serial reaction time task alcohol-exposed rats showed increased compulsivity and increased attentional bias towards a reward associated cue. Consistent with these changes, we observed decreased cell density in the prefrontal cortex. These findings confirm a detrimental effect of chronic alcohol and establish a model of alcohol-induced cognitive decline following long-term voluntary intake that may be used for future intervention studies.

Exercise-driven restoration of the alcohol-damaged brain

There are vast literatures on the neural effects of alcohol and the neural effects of exercise. Simply put, exercise is associated with brain health, alcohol is not, and the mechanisms by which exercise benefits the brain directly counteract the mechanisms by which alcohol damages it. Although a degree of brain recovery naturally occurs upon cessation of alcohol consumption, effective treatments for alcohol-induced brain damage are badly needed, and exercise is an excellent candidate from a mechanistic standpoint. In this chapter, we cover the small but growing literature on the interactive neural effects of alcohol and exercise, and the capacity of exercise to repair alcohol-induced brain damage. Increasingly, exercise is being used as a component of treatment for alcohol use disorders (AUD), not because it reverses alcohol-induced brain damage, but because it represents a rewarding, alcohol-free activity that could reduce alcohol cravings and improve comorbid conditions such as anxiety and depression. It is important to bear in mind, however, that multiple studies attest to a counterintuitive positive relationship between alcohol intake and exercise. We therefore conclude with cautionary notes regarding the use of exercise to repair the brain after alcohol damage.

Convergence of three parcellation approaches demonstrating cerebellar lobule volume deficits in Alcohol Use Disorder

Recent advances in robust and reliable methods of MRI-derived cerebellar lobule parcellation volumetry present the opportunity to assess effects of Alcohol Use Disorder (AUD) on selective cerebellar lobules and relations with indices of nutrition and motor functions. In pursuit of this opportunity, we analyzed high-resolution MRI data acquired in 24 individuals with AUD and 20 age- and sex-matched controls with a 32-channel head coil using three different atlases: the online automated analysis pipeline volBrain Ceres, SUIT, and the Johns Hopkins atlas. Participants had also completed gait and balance examination and hematological analysis of nutritional and liver status, enabling testing of functional meaningfulness of each cerebellar parcellation scheme. Compared with controls, each quantification approach yielded similar patterns of group differences in regional volumes: All three approaches identified AUD-related deficits in total tissue and total gray matter, but only Ceres identified a total white matter volume deficit. Convergent volume differences occurred in lobules I-V, Crus I, VIIIB, and IX. Coefficients of variation (CVs) were <20% for 46 of 56 regions measured and in general were graded: Ceres<SUIT<Hopkins. The most robust correlations were identified between poorer stability in balancing on one leg and smaller lobule VI and Crus I volumes from the Ceres atlas. Lower values of two essential vitamins-thiamine (vitamin B1) and serum folate (vitamin B9)-along with lower red blood cell count, which are dependent on adequate levels of B vitamins, correlated with smaller gray matter volumes of lobule VI and Crus I. Higher γ-glutamyl transferase (GGT) levels, possibly reflecting compromised liver function, correlated with smaller volumes of lobules VI and X. These initial results based on high resolution data produced with clinically practical imaging procedures hold promise for expanding our knowledge about the relevance of focal cerebellar morphology in AUD and other neuropsychiatric conditions.

Its complicated: The relationship between alcohol and microglia in the search for novel pharmacotherapeutic targets for alcohol use disorders

Alcohol use disorder (AUD) is a chronic relapsing disorder with wide-ranging health consequences. Alcohol targets the central nervous system producing neurodegeneration and subsequent cognitive and behavioral deficits, but the mechanisms behind these effects remain unclear. Recently, evidence has been mounting for the role of neuroimmune activation in the pathogenesis of AUDs, but our nascent state of knowledge about the interaction of alcohol with the neuroimmune system supports that the relationship is complicated. As the resident macrophage of the central nervous system, microglia are a central focus. Human and animal research on the interplay between microglia and alcohol in AUDs has proven to be complex, and though early research focused on a pro-inflammatory phenotype of microglia, the anti-inflammatory and homeostatic roles of microglia must be considered. How these new roles for microglia should be incorporated into our thinking about the neuroimmune system in AUDs is discussed in the context of developing novel pharmacotherapies for AUDs.

Re-investigating the effects of chronic smoking on the pathology of alcohol-related human brain damage

Both pathological and neuroimaging studies have shown that chronic alcohol abuse causes generalized white matter, but limited gray matter, volume loss. Recent neuroimaging studies suggest that tobacco smoking also causes brain atrophy in both alcoholics and neurologically normal individuals. However, a recent pathological study, employing a manual technique to determine regional volumes, found no significant effects of smoking on either global or selected regional gray matter volumes in smokers or smoking alcoholics. Here a high-resolution computerized method was employed in the same cohort to evaluate four regions where neuroimaging studies have found atrophy in smokers and alcoholics: insula, thalamus, prefrontal cortex, and anterior cingulate cortex. Brain images from 44 cases comprising 16 non-smoking controls, nine smoking controls, eight non-smoking alcoholics, and 11 smoking alcoholics were quantified. No significant differences between the groups were found, although the alcoholic groups tended to have smaller volumes in most regions. Furthermore, there were no smoking or interactive effects, and no correlation between gray matter volumes and either tobacco pack-years or lifetime alcohol consumption. These results do not support the hypotheses that tobacco smoking causes gray matter loss or that smoking potentiates gray matter atrophy in chronic alcoholics.

Chronic Neurologic Effects of Alcohol

Chronic alcohol use induces silent changes in the structure and function of the central and peripheral nervous systems that eventually result in irreversible, debilitating repercussions. Once identified, nutritional supplementation and cessation measures are critical in preventing further neurologic damage. The proposed mechanisms of neuronal injury in chronic alcohol abuse include direct toxic effects of alcohol and indirect effects, including those resulting from hepatic dysfunction, nutritional deficiencies, and neuroinflammation. Clinical manifestations include cerebellar ataxia, peripheral neuropathy and Wernicke-Korsakoff encephalopathy. Continued exploration of the pathophysiologic mechanisms may lead to the discovery of early interventions that can prevent permanent neurologic injury.

A Pivotal Role for Thiamine Deficiency in the Expression of Neuroinflammation Markers in Models of Alcohol-Related Brain Damage

BACKGROUND

Alcohol-related brain damage (ARBD) is associated with neurotoxic effects of heavy alcohol use and nutritional deficiency, in particular thiamine deficiency (TD), both of which induce inflammatory responses in brain. Although neuroinflammation is a critical factor in the induction of ARBD, few studies have addressed the specific contribution(s) of ethanol (EtOH) versus TD.

METHODS

Adult rats were randomly divided into 6 conditions: chronic EtOH treatment (CET) where rats consumed a 20% v/v solution of EtOH for 6 months; CET with injections of thiamine (CET + T); severe pyrithiamine-induced TD (PTD); moderate PTD; moderate PTD during CET; and pair-fed controls. After the treatments, the rats were split into 3 recovery phase time points: the last day of treatment (time point 1), acute recovery (time point 2: 24 hours posttreatment), and delayed recovery (time point 3: 3 weeks posttreatment). At these time points, vulnerable brain regions (thalamus, hippocampus, frontal cortex) were collected and changes in neuroimmune markers were assessed using a combination of reverse transcription polymerase chain reaction and protein analysis.

RESULTS

CET led to minor fluctuations in neuroimmune genes, regardless of the structure being examined. In contrast, PTD treatment led to a profound increase in neuroimmune genes and proteins within the thalamus. Cytokine changes in the thalamus ranged in magnitude from moderate (3-fold and 4-fold increase in interleukin-1β [IL-1β] and IκBα) to severe (8-fold and 26-fold increase in tumor necrosis factor-α and IL-6, respectively). Though a similar pattern was observed in the hippocampus and frontal cortex, overall fold increases were moderate relative to the thalamus. Importantly, neuroimmune gene induction varied significantly as a function of severity of TD, and most genes displayed a gradual recovery across time.

CONCLUSIONS

These data suggest an overt brain inflammatory response by TD and a subtle change by CET alone. Also, the prominent role of TD in the immune-related signaling pathways leads to unique regional and temporal profiles of induction of neuroimmune genes.

Chronic ethanol forced administration from adolescence to adulthood reduces cell density in the rat spinal cord

Ethanol (EtOH) consumption is a risk factor for central nervous system damage, especially during adolescence. This study aimed to investigate the possible effects of chronic EtOH forced administration on gray and white matter of the spinal cord, from adolescence to adulthood. For this, male Wistar rats were administered EtOH by gavage (6.5 g/kg/day; 22.5% w/v) from the 35th to the 90th day of life, while control animals received only distilled water. After exposure, animals were euthanized and their spinal cords processed to obtain cervical and thoracic segments for histological analyses. Quantitative analyses of total cell density and motor neurons of white and gray matter from the ventral horns were evaluated. Forced EtOH administration model showed a decrease in the motoneuron density in the spinal cord in both segments evaluated. Analyses of total cell density showed that the cervical segment was more susceptible to damages promoted by EtOH, with a significant decrease in cell density. Our results showed that chronic EtOH exposure during adolescence could promote injuries to the spinal cord, with neurodegeneration of motoneurons and other cell types present in neural parenchyma.

Comparing fully automated state-of-the-art cerebellum parcellation from magnetic resonance images

The human cerebellum plays an essential role in motor control, is involved in cognitive function (i.e., attention, working memory, and language), and helps to regulate emotional responses. Quantitative in-vivo assessment of the cerebellum is important in the study of several neurological diseases including cerebellar ataxia, autism, and schizophrenia. Different structural subdivisions of the cerebellum have been shown to correlate with differing pathologies. To further understand these pathologies, it is helpful to automatically parcellate the cerebellum at the highest fidelity possible. In this paper, we coordinated with colleagues around the world to evaluate automated cerebellum parcellation algorithms on two clinical cohorts showing that the cerebellum can be parcellated to a high accuracy by newer methods. We characterize these various methods at four hierarchical levels: coarse (i.e., whole cerebellum and gross structures), lobe, subdivisions of the vermis, and the lobules. Due to the number of labels, the hierarchy of labels, the number of algorithms, and the two cohorts, we have restricted our analyses to the Dice measure of overlap. Under these conditions, machine learning based methods provide a collection of strategies that are efficient and deliver parcellations of a high standard across both cohorts, surpassing previous work in the area. In conjunction with the rank-sum computation, we identified an overall winning method.

Disrupted topological organization of the motor execution network in alcohol dependence

Motor function damage is one of the most common symptoms in patients with alcohol dependence (AD). However, relatively little is known about the neuropathology of the motor impairments in AD. The aim of this study was to identify changes in the topological organization of the motor execution network in AD. Here, a total of 39 male individuals, including 19 AD patients and 20 age-matched healthy controls, underwent resting-state functional magnetic resonance imaging (fMRI). The motor execution network was constructed and analyzed using graph theoretical approaches. Topological properties (including global, nodal and edge measures) were compared between the two groups. At the global level, AD patients exhibited increased local specialization (indexed by increased clustering coefficient and local efficiency) relative to healthy controls, indicating that the motor execution network of AD patients shifts toward regularization. At the node level, nodal degree was higher in AD patients in the cerebellum. At the edge level, we observed a cerebello-thalamo-striato-cortical circuit with altered functional connectivity strength in AD patients. These findings suggest that topological architecture of the motor execution network is disrupted in AD patients, which may provide important insights into the neurobiology of the AD-related motor impairments.

Problematic alcohol use associates with sodium channel and clathrin linker 1 (SCLT1) in trauma-exposed populations

Excessive alcohol use is extremely prevalent in the United States, particularly among trauma-exposed individuals. While several studies have examined genetic influences on alcohol use and related problems, this has not been studied in the context of trauma-exposed populations. We report results from a genome-wide association study of alcohol consumption and associated problems as measured by the alcohol use disorders identification test (AUDIT) in a trauma-exposed cohort. Results indicate a genome-wide significant association between total AUDIT score and rs1433375 [N = 1036, P = 2.61 × 10^-8 (dominant model), P = 7.76 × 10^-8 (additive model)], an intergenic single-nucleotide polymorphism located 323 kb upstream of the sodium channel and clathrin linker 1 (SCLT1) at 4q28. rs1433375 was also significant in a meta-analysis of two similar, but independent, cohorts (N = 1394, P = 0.0004), the Marine Resiliency Study and Systems Biology PTSD Biomarkers Consortium. Functional analysis indicated that rs1433375 was associated with SCLT1 gene expression and cortical-cerebellar functional connectivity measured via resting state functional magnetic resonance imaging. Together, findings suggest a role for sodium channel regulation and cerebellar functioning in alcohol use behavior. Identifying mechanisms underlying risk for problematic alcohol use in trauma-exposed populations is critical for future treatment and prevention efforts.

Impairment of Thiamine Transport at the GUT-BBB-AXIS Contributes to Wernicke's Encephalopathy

Wernicke's encephalopathy, a common neurological disease, is caused by thiamine (vitamin B1) deficiency. Neuropathy resulting from thiamine deficiency is a hallmark of Wernicke-Korsakoff syndrome in chronic alcohol users. The underlying mechanisms of this deficiency and progression of neuropathy remain to be understood. To uncover the unknown mechanisms of thiamine deficiency in alcohol abuse, we used chronic alcohol consumption or thiamine deficiency diet ingestion in animal models. Observations from animal models were validated in primary human neuronal culture for neurodegenerative process. We employed radio-labeled bio-distribution of thiamine, qualitative and quantitative analyses of the various biomarkers and neurodegenerative process. In the present studies, we established that disruption of thiamine transport across the intestinal gut blood-brain barrier axis as the cause of thiamine deficiency in the brain for neurodegeneration. We found that reduction in thiamine transport across these interfaces was the cause of reduction in the synthesis of thiamine pyrophosphate (TPP), an active cofactor for pyruvate dehydrogenase E1α (PDHE1α). Our findings revealed that decrease in the levels of PDHE1α cofactors switched on the activation of PD kinase (PDK) in the brain, thereby triggering the neuronal phosphorylation of PDHE1α (p-PDHE1α). Dysfunctional phosphorylated PDHE1α causes the reduction of mitochondrial aerobic respiration that led to neurodegeneration. We concluded that impairment of thiamine transport across the gut-BBB-axis that led to insufficient TPP synthesis was critical to Wernicke-neuropathy, which could be effectively prevented by stabilizing the thiamine transporters.

Zingiber zerumbet L. (Smith) extract alleviates the ethanol-induced brain damage via its antioxidant activity

Background

Zingiber zerumbet (L.) Smith belongs to the Zingiberaceae family that is widely distributed throughout the tropics, particularly in Southeast Asia. It is locally known as ‘Lempoyang’ and traditionally used to treat fever, constipation and to relieve pain. It is also known to possess antioxidant and anti-inflammatory activities. Based on these antioxidant and anti-inflammatory activities, this study was conducted to investigate the effects of ethyl-acetate extract of Z. zerumbet rhizomes against ethanol-induced brain damage in male Wistar rats.

Method

Twenty-four male Wistar rats were divided into four groups which consist of normal, 1.8 g/kg ethanol (40% v/v), 200 mg/kg Z. zerumbet extract plus ethanol and 400 mg/kg Z. zerumbet plus ethanol. The extract of Z. zerumbet was given once daily by oral gavage, 30 min prior to ethanol exposure via intraperitoneal route for 14 consecutive days. The rats were then sacrificed. Blood and brain homogenate were subjected to biochemical tests and part of the brain tissue was sectioned for histological analysis.

Result

Treatment with ethyl-acetate Z. zerumbet extract at 200 mg/kg and 400 mg/kg significantly reduced the level of malondialdehyde (MDA) and protein carbonyl (p < 0.05) in the brain homogenate. Both doses of extracts also significantly increased the level of serum superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) activities as well as glutathione (GSH) level (p < 0.05). However, administration of ethyl-acetate Z. zerumbet extract at 400 mg/kg showed better protective effects on the ethanol-induced brain damage as shown with higher levels of SOD, CAT, GPx and GSH in the brain homogenate as compared to 200 mg/kg dose. Histological observation of the cerebellum and cerebral cortex showed that the extract prevented the loss of Purkinje cells and retained the number and the shape of the cells.

Conclusion

Ethyl-acetate extract of Z. zerumbet has protective effects against ethanol-induced brain damage and this is mediated through its antioxidant properties.

Graphical abstract

Z. zerumbet extract protects against ethanol-induced brain damage via its antioxidant properties

Eye movements, sensorimotor adaptation and cerebellar-dependent learning in autism: toward potential biomarkers and subphenotypes

Because of the wide range of symptoms expressed in individuals with autism spectrum disorder (ASD) and their idiosyncratic severity, it is unlikely that a single remedial approach will be universally effective. Resolution of this dilemma requires identifying subgroups within the autism spectrum, based on symptom set and severity, on an underlying neuro-structural difference, and on specific behavioral dysfunction. This will provide critical insight into the disorder and may lead to better diagnoses, and more targeted remediation in these subphenotypes of people with ASD. In this review, we discuss findings that appear to link the structure of the cerebellar vermis and plasticity of the saccadic eye-movement system in people with an autism spectrum disorder (ASD). Differences in cerebellar vermis structure in ASD could critically impact visuo-sensorimotor development in early infancy, which may in turn manifest as the visual orienting, communication and social interaction differences often seen in this population. It may be possible to distinguish a subpopulation of children with vermal hypoplasia, to establish whether this group manifests more severe deficits in visual orienting and in adaptation to persistent visual errors, and to establish whether this putative subphenotype of ASD is associated with a specific and distinct clinical symptom profile.

Alcohol affects brain functional connectivity and its coupling with behavior: greater effects in male heavy drinkers

Acute and chronic alcohol exposure significantly affect behavior but the underlying neurobiological mechanisms are still poorly understood. Here, we used functional connectivity density (FCD) mapping to study alcohol-related changes in resting brain activity and their association with behavior. Heavy drinkers (HD, N=16, 16 males) and normal controls (NM, N=24, 14 males) were tested after placebo and after acute alcohol administration. Group comparisons showed that NM had higher FCD in visual and prefrontal cortices, default mode network regions and thalamus, while HD had higher FCD in cerebellum. Acute alcohol significantly increased FCD within the thalamus, impaired cognitive and motor functions, and affected self-reports of mood/drug effects in both groups. Partial least squares regression showed that alcohol-induced changes in mood/drug effects were associated with changes in thalamic FCD in both groups. Disruptions in motor function were associated with increases in cerebellar FCD in NM and thalamus FCD in HD. Alcohol-induced declines in cognitive performance were associated with connectivity increases in visual cortex and thalamus in NM, but in HD, increases in precuneus FCD were associated with improved cognitive performance. Acute alcohol reduced 'neurocognitive coupling', the association between behavioral performance and FCD (indexing brain activity), an effect that was accentuated in HD compared with NM. Findings suggest that reduced cortical connectivity in HD contribute to decline in cognitive abilities associated with heavy alcohol consumption, whereas increased cerebellar connectivity in HD may have compensatory effects on behavioral performance. The results reveal how drinking history alters the association between brain FCD and individual differences in behavioral performance.

Long-Term Mortality of Patients with an Alcohol-Related Wernicke–Korsakoff Syndrome

Aims

To characterize a series of contemporary patients with alcohol-related Wernicke's encephalopathy (WE) or Korsakoff's syndrome (KS) and to update the current prognosis of disease.

Methods

Retrospective and prospective study of patients diagnosed with an alcohol-related WE or KS between 2002 and 2011 in a tertiary hospital. Socio-demographic, alcohol use characteristics, signs and symptoms, co-morbidity and blood parameters were obtained at admission. Patients were followed up until 2013 and causes of death were ascertained through the review of charts.

Results

Sixty-one patients were included (51 with WE and 10 with KS). Among patients with WE, 78% were men and age at diagnosis was 57 years (interquartile range (IQR): 49–66). Twenty-three percent fulfilled the classic WE triad. Regarding Caine's criteria for WE, 70.6% presented with at least two out of four signs or symptoms. Median follow-up of patients with WE syndrome was 5.3 years (IQR: 2.6–8.8), the cumulated mortality was 45% and death rate of 7.4 × 100 person-years (95% confidence interval (CI): 4.8–10.9). Overall, 50% of patients would be expected to die within 8 years of WE episode and main causes of death included serious bacterial infections (44.5%) and cancer (33.3%).

Conclusions

Survival of patients with an alcohol-related Wernicke–Korsakoff syndrome is poor; pursuing treatment of alcohol use disorder and early diagnosis of thiamine deficiency is a priority for improving clinical outcomes.

Korsakoff's syndrome: a critical review

In this review, we present a survey on Korsakoff's syndrome (KS), a residual syndrome in patients who suffered from a Wernicke encephalopathy (WE) that is predominantly characterized by global amnesia, and in more severe cases also by cognitive and behavioral dysfunction. We describe the history of KS and its definition, its epidemiology, and the lack of consensus criteria for its diagnosis. The cognitive and behavioral symptoms of KS, which include anterograde and retrograde amnesia, executive dysfunction, confabulation, apathy, as well as affective and social-cognitive impairments, are discussed. Moreover, recent insights into the underlying neurocognitive mechanisms of these symptoms are presented. In addition, the evidence so far on the etiology of KS is examined, highlighting the role of thiamine and alcohol and discussing the continuity hypothesis. Furthermore, the neuropathology of KS is reviewed, focusing on abnormalities in the diencephalon, including the mammillary bodies and thalamic nuclei. Pharmacological treatment options and nonpharmacological interventions, such as those based on cognitive rehabilitation, are discussed. Our review shows that thiamine deficiency (TD) is a crucial factor in the etiology of KS. Although alcohol abuse is by far the most important context in which TD occurs, there is no convincing evidence for an essential contribution of ethanol neurotoxicity (EN) to the development of WE or to the progression of WE to KS. Future research on the postmortem histopathological analysis of brain tissues of KS patients is crucial for the advancement of our knowledge of KS, especially for associating its symptoms with lesions in various thalamic nuclei. A necessary requirement for the advancement of studies on KS is the broad acceptance of a comprehensive definition and definite diagnostic criteria. Therefore, in this review, we propose such a definition of KS and draft outlines for prospective diagnostic criteria.

Alcohol-related cognitive impairment: current trends and future perspectives

Excessive alcohol use is associated with a wide range of physical, psychological and social consequences, and is responsible for a significant proportion of the burden of disease globally. An area which has received increasing interest is alcohol-related brain damage, not just because of the cost to the individual and society through resource utilization, but also because of the potential for prevention and reversibility. This paper aims to review the current literature on this subject and seeks to explore issues around diagnosis and treatment of alcohol-related brain damage.

Ethanol-Induced Alterations in Purkinje Neuron Dendrites in Adult and Aging Rats: a Review

Uncomplicated alcoholics suffer from discrete motor dysfunctions that become more pronounced with age. These deficits involve the structure and function of Purkinje neurons (PN), the sole output neurons from the cerebellar cortex. This review focuses on alterations to the PN dendritic arbor in the adult and aging Fischer 344 rat following lengthy alcohol consumption. It describes seminal studies using the Golgi-Cox method which proposed a model for ethanol-induced dendritic regression. Subsequent ultrastructural studies of PN dendrites showed dilation of the extensive smooth endoplasmic reticulum (SER) which preceded and accompanied dendritic regression. The component of the SER that was most affected by ethanol was the sarco/endoplasmic reticulum Ca(2+) ATPase pump (SERCA) responsible for resequestration of calcium into the SER. Ethanol-induced decreases in SERCA pump levels, similar to the finding of SER dilation, preceded and occurred concomitantly with dendritic regression. Discrete ethanol-induced deficits in balance also accompanied these decreases. Ethanol-induced ER stress within the SER of PN dendrites was proposed as an underlying cause of dendritic regression. It was recently shown that increased activation of caspase 12, inherent to the ER, occurred in PN of acute slices in ethanol-fed rats and was most pronounced following 40 weeks of ethanol treatment. These findings shed new light into alcohol-induced disruption in PN dendrites providing a new model for the discrete but critical changes in motor function in aging, adult alcoholics.

Altered CB1 receptor coupling to G-proteins in the post-mortem caudate nucleus and cerebellum of alcoholic subjects

Biochemical, pharmacological and genetic evidence suggests the involvement of the endocannabinoid system in alcohol dependence. The aim of the present study was to evaluate the state of CB1 receptors in post-mortem caudate nucleus, hippocampus and cerebellum of alcoholic subjects.CB1 protein levels were measured by Western blot, CB1 receptor density and affinity by [(3)H]WIN55,212-2 saturation assays and CB1 functionality by [(35)S]GTPγS binding assays. Experiments were performed in samples from 24 subjects classified as non-suicidal alcoholics (n = 6), suicidal alcoholics (n = 6), non-alcoholic suicide victims (n = 6) and control subjects (n = 6).Alcoholic subjects presented hyperfunctional CB1 receptors in the caudate nucleus resulting in a higher maximal effect in both alcoholic groups compared to the non-alcoholic groups (p < 0.001). Conversely, in the cerebellum the non-suicidal alcoholic subjects showed hypofunctional receptors with lower maximal effect and potency (p < 0.001). No changes were found in the CB1 protein expression in either region. In the hippocampus of alcoholic subjects, no changes were observed either in the functionality, density or protein levels.Our data support an association between endocannabinoid system activity and alcoholism. The modifications reported here could be either a consequence of high lifetime ethanol consumption or a vulnerability factor to develop alcohol addiction.

T2 relaxation time alterations underlying neurocognitive deficits in alcohol-use disorders (AUD) in an Indian population: A combined conventional ROI and voxel-based relaxometry analysis

Long-term heavy alcohol consumption has traditionally been associated with impaired cognitive abilities, such as deficits in abstract reasoning, problem solving, verbal fluency, memory, attention, and visuospatial processing. The present study aimed at exploring these neuropsychological deficits in alcohol-use disorders (AUD) in an Indian population using the Postgraduate Institute Battery of Brain Dysfunction (PGIBBD) and their possible correlation with alterations in T2 relaxation times (T2-RT), using whole-brain voxel-based relaxometry (VBR) and conventional region of interest (ROI) approach. Multi-echo T2 mapping sequence was performed on 25 subjects with AUD and 25 healthy controls matched for age, education, and socioeconomic status. Whole-brain T2-RT measurements were conducted using VBR and conventional ROI approach. The study was carried out on a 3T whole-body MR scanner. Post processing for VBR and ROI analysis was performed using SPM 8 software and vendor-provided software, respectively. A PGIBBD test battery was conducted on all subjects to assess their cognitive abilities, and the results were reported as raw scores. VBR and ROI results revealed that AUD subjects showed prolonged T2-RTs in cerebellum bilaterally, parahippocampal gyrus bilaterally, right anterior cingulate cortex, left superior temporal gyrus, left middle frontal gyrus, and left calcarine gyrus. A significant correlation was also observed between the neuropsychological test raw scores and alterations in T2-RT in AUD subjects. Our results are consistent with previous studies suggesting tissue disruption or gliosis or demyelination as a possible reason for prolonged T2-RTs. This damage to brain tissue, which is evident as prolonged T2-RT, could possibly be associated with impaired cognitive abilities noticeable in AUD subjects.

Cognitive demands during quiet standing elicit truncal tremor in two frequency bands: differential relations to tissue integrity of corticospinal tracts and cortical targets

The ability to stand quietly is disturbed by degradation of cerebellar systems. Given the complexity of sensorimotor integration invoked to maintain upright posture, the integrity of supratentorial brain structures may also contribute to quiet standing and consequently be vulnerable to interference from cognitive challenges. As cerebellar system disruption is a common concomitant of alcoholism, we examined 46 alcoholics and 43 controls with a force platform to derive physiological indices of quiet standing during cognitive (solving simple, mental arithmetic problems) and visual (eyes closed) challenges. Also tested were relations between tremor velocity and regional gray matter and white matter tissue quality measured with the diffusion tensor imaging (DTI) metric of mean diffusivity (MD), indexing disorganized microstructure. Spectral analysis of sway revealed greater tremor in alcoholic men than alcoholic women or controls. Cognitive dual-tasking elicited excessive tremor in two frequency bands, each related to DTI signs of degradation in separate brain systems: tremor velocity at a low frequency (2–5 Hz/0–2 Hz) correlated with higher MD in the cerebellar hemispheres and superior cingulate bundles, whereas tremor velocity at a higher frequency (5–7 Hz) correlated with higher MD in the motor cortex and internal capsule. These brain sites may represent “tremorgenic networks” that, when disturbed by disease and exacerbated by cognitive dual-tasking, contribute to postural instability, putting affected individuals at heightened risk for falling.

Metronidazole-induced encephalopathy after prolonged metronidazole course for treatment of C. difficile colitis

A 65-year-old woman with a diagnosis of Clostridium difficile colitis undergoing prolonged treatment with metronidazole was admitted to hospital for altered mentation, slurred speech and weakness. She was diagnosed with metronidazole-induced encephalopathy, confirmed with brain MRI and improved when the offending agent was removed. This case report highlights encephalopathy as a complication of prolonged metronidazole treatment, which has become more common in clinical practice for the treatment of C. difficile infection.

PKR downregulation prevents neurodegeneration and β-amyloid production in a thiamine-deficient model

Brain thiamine homeostasis has an important role in energy metabolism and displays reduced activity in Alzheimer's disease (AD). Thiamine deficiency (TD) induces regionally specific neuronal death in the animal and human brains associated with a mild chronic impairment of oxidative metabolism. These features make the TD model amenable to investigate the cellular mechanisms of neurodegeneration. Once activated by various cellular stresses, including oxidative stress, PKR acts as a pro-apoptotic kinase and negatively controls the protein translation leading to an increase of BACE1 translation. In this study, we used a mouse TD model to assess the involvement of PKR in neuronal death and the molecular mechanisms of AD. Our results showed that the TD model activates the PKR-eIF2α pathway, increases the BACE1 expression levels of Aβ in specific thalamus nuclei and induces motor deficits and neurodegeneration. These effects are reversed by PKR downregulation (using a specific inhibitor or in PKR knockout mice).

Wernicke encephalopathy and ethanol-related syndromes

Ethanol causes diverse neurologic conditions caused by acute and chronic brain damage. This review provides an overview of Wernicke encephalopathy and other ethanol-related brain changes, such as chronic brain atrophy, Marchiafava-Bignami disease, osmotic demyelination syndrome, chronic hepatic encephalopathy, and acute alcohol withdrawal. As clinical symptoms of this spectrum of diseases have nonspecific neurologic alterations, radiologists should have current radiologic information and understand the imaging findings pertaining to the pathophysiology to support diagnosis.

Ethanol Mediates Cell Cycle Arrest and Apoptosis in SK-N-SH Neuroblastoma Cells

Background:

The mechanisms of cell or organ damage by chronic alcohol consumption are still poorly understood. The present study aimed to investigate the role of the mitogen-activated protein kinases during ethanol-induced damage to SK-N-SH neuroblastoma cells.

Methods:

Cells were treated with ethanol and subsequently analyzed for cell morphology, viability, and DNA fragmentation. Immunoblot analysis was performed to assess various proteins levels associated with cell cycle arrest and apoptosis after ethanol exposure.

Results:

Ethanol induced time- and dose-dependent cell death in SK-N-SH cells and increased c-Jun N-terminal protein kinase (JNK) activity in a time- and concentration dependent manner. In contrast, p38 kinase activity increased transiently. After treatment with JNK or p38 kinase inhibitors, ethanol-induced cell death significantly reduced. Ethanol-induced cell death was accompanied by increased cytochrome c release and caspase 3 activity observed at 12 h. In contrast, the level of anti-apoptotic Bcl-2 protein did not change. Ethanol also increased the phosphorylation of p53 and p53 activation was followed by an increase in the p21 tumor suppressor protein accompanied by a gradual decrease in phospho-Rb protein.

Conclusion:

Our results suggest that ethanol mediates apoptosis of neuroblastoma cells by stimulating p53-related cell cycle arrest mediated through activation of the JNK-related pathway.

Neuropathology of Chronic Alcohol Abuse

Alcohol abuse and dependence are serious public health problems worldwide, resulting in significant morbidity, mortality, and legal implications. Therefore, sudden unexpected, suspicious, or violent death in alcohol consuming persons are frequently seen in the forensic setting. Alcohol-induced brain damage is predominantly caused by nutritional deficiencies and repeated withdrawal syndrome. Brain lesions associated with heavy alcohol consumption include brain atrophy, hepatic encephalopathy, and central pontine myelinolysis. In addition, the dementing conditions Wernicke-Korsakoff syndrome, acquired hepatocerebral degeneration, Marchiafava-Bignami disease, and pellagrous encephalopathy are closely associated with chronic alcohol consumption. In neuroradiological and autopsy studies, cerebral and cerebellar atrophy has been demonstrated in alcoholics. There is a regional selectivity, with the frontal lobes being particularly affected. Moreover, a disproportionate loss of cerebral white matter relative to cerebral cortex suggests that a major neurotoxic effect of chronic alcohol consumption predominantly affects the white matter.

Decreased white matter integrity in fronto-occipital fasciculus bundles: relation to visual information processing in alcohol-dependent subjects

Chronic alcohol abuse is characterized by impaired cognitive abilities with a more severe deficit in visual than in verbal functions. Neuropathologically, it is associated with widespread brain structural compromise marked by gray matter shrinkage, ventricular enlargement, and white matter degradation. The present study sought to increase current understanding of the impairment of visual processing abilities in alcohol-dependent subjects, and its correlation with white matter microstructural alterations, using diffusion tensor imaging (DTI). To that end, a DTI study was carried out on 35 alcohol-dependent subjects and 30 healthy male control subjects. Neuropsychological tests were assessed for visual processing skills and deficits were reported as raw dysfunction scores (rDyS). Reduced FA (fractional anisotropy) and increased MD (mean diffusivity) were observed bilaterally in inferior and superior fronto-occipital fasciculus (FOF) fiber bundles. A significant inverse correlation in rDyS and FA values was observed in these fiber tracts whereas a positive correlation of these scores was found with the MD values. Our results suggest that FOF fiber bundles linking the frontal lobe to occipital lobe might be related to visual processing skills. This is the first report of an alteration of the white matter microstructure of FOF fiber bundles that might have functional consequences for visual processing in alcohol-dependent subjects who exhibit no neurological complications.

Traumatic basal subarachnoid hemorrhage suspected to have been caused by contrecoup cerebellar contusions: a case report

Traumatic cerebellar hemorrhagic contusions are infrequent, and the pathogenic mechanism involves a coup injury that is associated with motor vehicle accidents in most cases. Traumatic basal subarachnoid hemorrhage (TBSAH) is commonly reported after blunt trauma to the neck or unrestricted movement of the head, and the source of the hemorrhage is most frequently identified in the vertebrobasilar arteries. A 55-year-old woman who was addicted to alcohol was found dead in her bed. She had a bruise on the left side of her posterior parietal region, and autopsy revealed massive subarachnoid hemorrhage at the base of the brain; the hematoma was strongly attached to the right lower surface of the cerebellar hemisphere. No ruptured cerebral aneurysms, arteriovenous malformations or vertebrobasilar artery leakage were detected. Hemorrhagic cerebellar contusions were regarded as the source of the TBSAH. This is the first report of TBSAH suspected to have been caused by contrecoup cerebellar contusions.

Automated cerebellar segmentation: Validation and application to detect smaller volumes in children prenatally exposed to alcohol

OBJECTIVE

To validate an automated cerebellar segmentation method based on active shape and appearance modeling and then segment the cerebellum on images acquired from adolescents with histories of prenatal alcohol exposure (PAE) and non-exposed controls (NC).

METHODS

Automated segmentations of the total cerebellum, right and left cerebellar hemispheres, and three vermal lobes (anterior, lobules I-V; superior posterior, lobules VI-VII; inferior posterior, lobules VIII-X) were compared to expert manual labelings on 20 subjects, studied twice, that were not used for model training. The method was also used to segment the cerebellum on 11 PAE and 9 NC adolescents.

RESULTS

The test-retest intraclass correlation coefficients (ICCs) of the automated method were greater than 0.94 for all cerebellar volume and mid-sagittal vermal area measures, comparable or better than the test-retest ICCs for manual measurement (all ICCs > 0.92). The ICCs computed on all four cerebellar measurements (manual and automated measures on the repeat scans) to compare comparability were above 0.97 for non-vermis parcels, and above 0.89 for vermis parcels. When applied to patients, the automated method detected smaller cerebellar volumes and mid-sagittal areas in the PAE group compared to controls (p < 0.05 for all regions except the superior posterior lobe, consistent with prior studies).

DISCUSSION

These results demonstrate excellent reliability and validity of automated cerebellar volume and mid-sagittal area measurements, compared to manual measurements. These data also illustrate that this new technology for automatically delineating the cerebellum leads to conclusions regarding the effects of prenatal alcohol exposure on the cerebellum consistent with prior studies that used labor intensive manual delineation, even with a very small sample.