Whole-brain morphometric studies in alcohol addicts by voxel-based morphometry

Altered individual gray matter structural covariance networks in early abstinence patients with alcohol dependence

While alterations in cortical thickness have been widely observed in individuals with alcohol dependence, knowledge about cortical thickness-based structural covariance networks is limited. This study aimed to explore the topological disorganization of structural covariance networks based on cortical thickness at the single-subject level among patients with alcohol dependence. Structural imaging data were obtained from 61 patients with alcohol dependence during early abstinence and 59 healthy controls. The single-subject structural covariance networks were constructed based on cortical thickness data from 68 brain regions and were analyzed using graph theory. The relationships between network architecture and clinical characteristics were further investigated using partial correlation analysis. In the structural covariance networks, both patients with alcohol dependence and healthy controls displayed small-world topology. However, compared to controls, alcohol-dependent individuals exhibited significantly altered global network properties characterized by greater normalized shortest path length, greater shortest path length, and lower global efficiency. Patients exhibited lower degree centrality and nodal efficiency, primarily in the right precuneus. Additionally, scores on the Alcohol Use Disorder Identification Test were negatively correlated with the degree centrality and nodal efficiency of the left middle temporal gyrus. The results of this correlation analysis did not survive after multiple comparisons in the exploratory analysis. Our findings may reveal alterations in the topological organization of gray matter networks in alcoholism patients, which may contribute to understanding the mechanisms of alcohol addiction from a network perspective.

Hereditary and cortical morphological biomarker of sensitivity to reward in short-term withdrawal methamphetamine abusers

Higher sensitivity to reward (SR) and weaker sensitivity to punishment (SP) construct the fundamental craving characteristics of methamphetamine abuse. However, few studies have appraised relationships between SR/SP (SR or SP) and cortical morphological alterations in methamphetamine abusers and whether hereditary factors take effects on SR/SP is unclear. Based on surface-based morphometric analysis, cortical discrepancy was investigated between 38 methamphetamine abusers and 37 healthy controls. Within methamphetamine abusers, correlation profiling was performed to discover associations among aberrant neuroimaging substrates, SR, SP, and craving. According to nine single nucleotide polymorphism sites of dopamine-related genes, we conducted univariate general linear model to find different effects of genotypes on cortical alterations and SR/SP/craving (SR, SP, or craving). Ultimately, mediation analyses were conducted among single nucleotide polymorphism sites, SR/SP/craving, and cortical morphological alterations to discover their association pathways. Compared to healthy controls, thinner cortices in inferior temporal gyrus, lateral orbitofrontal cortex, medial orbitofrontal cortex, inferior parietal lobule, and lateral occipital cortex in the left hemisphere were found in methamphetamine abusers (P < 0.05, family-wise error corrected). Cortical thickness in the inferior temporal gyrus was negatively correlated with SR scores. We found that rs1800497 A-containing genotypes had lower cortical thickness in the left inferior parietal lobule than the GG genotype. The rs5751876 had effects on SR scores. This study would provide convincing biomarkers for SR in methamphetamine abusers and offer potential genetic targets for personalizing relapse prevention.

Examination of reward processing dysfunctions in the left dorsal striatum and other brain regions among psychiatric inpatients with substance use

BACKGROUND

Substance misuse is a major public health issue and research has established attenuated reward responses to drug cues in those who misuse substances. Yet, little is known about whether the expectation of natural reinforcers engages distinct brain regions in substance misuse.

METHODS

Using functional magnetic resonance imaging (fMRI), we delivered juice at expected and unexpected times to examine reward processing dysfunctions. We focused on the responses within the left dorsal striatum (DS) in individuals with high-risk substance use (HRU, n = 65), low-risk substance use (psychiatric controls, PC, n = 65), and healthy controls (HC, n = 65). Additionally, we investigated whether the dysfunction in reward processing within the left DS is correlated with other common psychiatric symptoms. Finally, we conducted a comprehensive analysis of the whole brain to investigate other non-hypothesized brain regions.

RESULTS

Compared to HC, HRU displayed lower responses to juice delivery (i.e., reward) in the left DS (p <.05). The whole-brain analysis demonstrated that compared to HC, HRU displayed significantly lower responses to reward stimuli in various brain regions, including the bilateral caudate, temporal gyrus, left frontal gyrus, middle frontal gyrus, and right thalamus.

LIMITATIONS

Participants were individuals with polysubstance use; therefore, we were not able to examine the effects of individual substances.

CONCLUSIONS

Our findings suggest that HRU displays lower responses to reward stimuli within the left DS and other non-hypothesized brain regions. Our findings may help further elucidate reward processing dysfunctions related to substance misuse.

Effects of current alcohol use on brain volume among older adults in the Gothenburg H70 Birth Cohort study 2014-16

Brain gray- and white matter changes is well described in alcohol-dependent elderly subjects; however, the effect of lower levels of alcohol consumption on the brain is poorly understood. We investigated the impact of different amounts of weekly alcohol consumption on brain structure in a population-based sample of 70-year-olds living in Gothenburg, Sweden. Cross-sectional data from 676 participants from The Gothenburg H70 Birth Cohort Study 2014-16 were included. Current alcohol consumers were divided into seven groups based on self-reported weekly amounts of alcohol consumption in grams (g) (0-50 g/week, used as reference group, 51-100 g/week, 101-150 g/week, 151-200 g/week, 201-250 g/week, 251-300 g/week, and > 300 g/week). Subcortical volumes and cortical thickness were assessed on T1-weighted structural magnetic resonance images using FreeSurfer 5.3, and white matter integrity assessed on diffusion tensor images, using tract-based statistics in FSL. General linear models were carried out to estimate associations between alcohol consumption and gray- and white matter changes in the brain. Self-reported consumption above 250 g/week was associated with thinning in the bilateral superior frontal gyrus, the right precentral gyrus, and the right lateral occipital cortex, in addition to reduced fractional anisotropy (FA) and increased mean diffusivity (MD) diffusively spread in many tracts all over the brain. No changes were found in subcortical gray matter structures. These results suggest that there is a non-linear relationship between alcohol consumption and structural brain changes, in which loss of cortical thickness only occur in non-demented 70-year-olds who consume more than 250 g/week.

Disrupted white matter structural networks in individuals with alcohol dependence

Previous diffusion tensor imaging (DTI) studies have demonstrated widespread white matter microstructure damage in individuals with alcoholism. However, very little is known about the alterations in the topological architecture of white matter structural networks in alcohol dependence (AD). This study included 67 AD patients and 69 controls. The graph theoretical analysis method was applied to examine the topological organization of the white matter structural networks, and network-based statistics (NBS) were employed to detect structural connectivity alterations. Compared to controls, AD patients exhibited abnormal global network properties characterized by increased small-worldness, normalized clustering coefficient, clustering coefficient, and shortest path length; and decreased global efficiency and local efficiency. Further analyses revealed decreased nodal efficiency and degree centrality in AD patients mainly located in the default mode network (DMN), including the precuneus, anterior cingulate and paracingulate gyrus, median cingulate and paracingulate gyrus, posterior cingulate gyrus, and medial part of the superior frontal gyrus. Furthermore, based on NBS approaches, patients displayed weaker subnetwork connectivity mainly located in the region of the DMN. Additionally, altered network metrics were correlated with intelligence quotient (IQ) scores and global assessment function (GAF) scores. Our results may reveal the disruption of whole-brain white matter structural networks in AD individuals, which may contribute to our comprehension of the underlying pathophysiological mechanisms of alcohol addiction at the level of white matter structural networks.

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

BACKGROUND

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

METHOD

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

RESULTS

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

CONCLUSIONS

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

Effect of alcohol, tobacco, and cannabis co-use on gray matter volume in heavy drinkers

OBJECTIVE

Alcohol, tobacco, and cannabis are the three most frequently used drugs in the United States and co-use is common. Alcohol, tobacco, and cannabis use has been separately associated with altered brain structure, and alcohol and tobacco co-use results in decreases in gray matter volume. Less is known about the effect of alcohol and cannabis co-use, and alcohol, tobacco, and cannabis tri-use. Therefore, this study examined the effect of co- and tri-use on gray matter volume, a measure of brain cell density, in heavy drinkers.

METHOD

Heavy drinkers (n = 237; 152m/85f; age = 32.52; white = 111; black = 28; Latino = 9; American Indian = 2; Pacific Islander = 4; Asian = 59; mixed = 15; other = 9) were classified into four groups based on their alcohol, tobacco, and cannabis use: alcohol only users (n = 70), alcohol and tobacco co-users (n = 90), alcohol and cannabis co-users (n = 35), and alcohol, tobacco, and cannabis tri-users (n = 42). All participants completed a structural MRI scan. Voxel-based morphometry was conducted to evaluate the effect of co-use on gray matter volume, with alcohol only users as the reference group. Age, sex, and scanner were included as covariates.

RESULTS

Alcohol and tobacco co-users had significantly decreased left orbitofrontal gray matter volume relative to alcohol only users (Cohen's d = .79). There were no differences in gray matter volume between the alcohol only and alcohol and cannabis co-users, or between the alcohol only and tri-user groups.

CONCLUSION

The additive effect of tobacco co-use on gray matter volumes in heavy drinkers was limited and localized. The effect of tri-use of alcohol, tobacco, and cannabis may have interacted, such that overlapping cannabis and tobacco use masked volume differences present in separate co-using groups. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Frontocerebellar gray matter plasticity in alcohol use disorder linked to abstinence

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GM loss in frontocerebellar circuit predicts relapse.

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GM recovery in AUD involves distinct neural processes.

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Recovery is not a reversal of any AUD-related GM damage.

Alcohol use disorder (AUD) is associated with brain-wide gray matter (GM) reduction, but the frontocerebellar circuit seems specifically affected by chronic alcohol consumption. T1 weighted MRI data from 38 AUD patients at one month of sobriety and three months later and from 25 controls were analyzed using voxel-based morphometry (VBM) and a graph theory approach (GTA). We investigated the degree to which the frontocerebellar circuit’s integration within the brain’s GM network architecture was altered by AUD-related GM volume loss. The VBM analyses did not reveal significant GM volume differences between relapsers and abstainers at either timepoint, but future relapsers at both timepoints had significantly less GM than controls in the frontocerebellar circuit. Abstainers, who at baseline also showed the most pronounced GM loss in the thalamus, showed a significant circuit-wide GM increase with inter-scan abstinence. The post-hoc GTAs revealed a persistent diffuse global atrophy in both AUD groups at follow-up relative to controls and different recovery patterns in the two AUD groups. Our findings suggest that future relapsers do not just present with a more severe expression of the same AUD consequences than abstainers, but that AUD affects the frontocerebellar circuit differently in relapsers and abstainers.

Neurofilament Light Chain Is a Promising Biomarker in Alcohol Dependence

Background: Alcohol dependence, a global public health problem, leads to structural and functional damage in the brain. Alcohol dependence patients present complex and varied clinical manifestations and live with general complaints existing in contemporary society, making most people with alcohol dependence hard to identify. Therefore, it is important to find potential biomarkers for the diagnosis and evaluation of alcohol dependence. In the study, we explored potential biomarkers for the diagnosis and monitoring of diseases and evaluated brain structural changes in alcohol dependence patients. Methods: Enzyme-linked immunosorbent assay (ELSA) was employed to detect the expression of serum nucleotide-binding oligomerization domain containing 3 (NLRP3) and single-molecule array (Simoa) assay was used to detect the expression of serum neurofilament light (NfL) in 50 alcohol dependence patients and 50 controls with no drinking history. Alcohol consumption was measured by standard drinks. Neuropsychological assessments, including the Montreal cognitive assessment (MoCA), Pittsburgh sleep quality index (PSQI), generalized anxiety disorder (GAD-7), and patient health questionnaire-9 (PHQ-9), were conducted to evaluate cognitive function and psychological state. The degree of white matter lesions (WMLs) was rated using the Fazekas scale based on magnetic resonance imaging analysis. White matter structure was quantified using the voxel-based morphometry method. The correlations between NLRP3 levels, NfL levels, neuropsychological dysfunction, the degree of WMLs, and white matter volume (WMV) were analyzed in alcohol dependence patients. Results: Serum NLRP3 and NfL levels were higher in the alcohol dependence group. NLRP3 levels were irrelevant to monthly alcohol assumption as well as to the MoCA, PSQI, GAD-7, PHQ-9, and Fazekas scale scores and WMV. NfL levels were positively correlated with the PSQI and PHQ-9 scores as well as the degree of WMLs and negatively correlated with the MoCA scores and WMV. No associations were evident between NfL and monthly alcohol assumption and GAD-7 scores in the alcohol dependence group. Conclusion: This study supports the potential value of serum NfL as a non-invasive biomarker in alcohol dependence. The association with neuropsychological dysfunction and degree of WMLs has implications to use NfL as a promising biomarker to assess the severity of brain damage as well as the progression and prognosis of alcohol dependence.