Alteration of Brain Structure With Long-Term Abstinence of Methamphetamine by Voxel-Based Morphometry

Individual differences and motor planning influence self-recognition of actions

Although humans can recognize their body movements in point-light displays, self-recognition ability varies substantially across action types and participants. Are these variations primarily due to an awareness of visually distinct movement patterns, or to underlying factors related to motoric planning and/or individual differences? To address this question, we conducted a large-scale study in self-action recognition (N = 101). We motion captured whole-body movements of participants who performed 27 different actions across action goals and degree of motor planning. After a long delay period (~ 1 month), participants were tested in a self-recognition task: identifying their point-light action amongst three other point-light actors performing identical actions. We report a self-advantage effect from point-light actions, consistent with prior work in self-action recognition. Further, we found that self-recognition was modulated by the action complexity (associated with the degree of motor planning in performed actions) and individual differences linked to motor imagery and subclinical autism and schizotypy. Using dynamic time warping, we found sparse evidence in support of visual distinctiveness as a primary contributor to self-recognition, though speed distinctiveness negatively influenced self-recognition performance. Together, our results reveal that self-action recognition involves more than an awareness of visually distinct movements, with important implications for how the motor system may be involved.

An electroencephalographic signature predicts craving for methamphetamine

Craving is central to methamphetamine use disorder (MUD) and both characterizes the disease and predicts relapse. However, there is currently a lack of robust and reliable biomarkers for monitoring craving and diagnosing MUD. Here, we seek to identify a neurobiological signature of craving based on individual-level functional connectivity pattern differences between healthy control and MUD subjects. We train high-density electroencephalography (EEG)-based models using data recorded during the resting state and then calculate imaginary coherence features between the band-limited time series across different brain regions of interest. Our prediction model demonstrates that eyes-open beta functional connectivity networks have significant predictive value for craving at the individual level and can also identify individuals with MUD. These findings advance the neurobiological understanding of craving through an EEG-tailored computational model of the brain connectome. Dissecting neurophysiological features provides a clinical avenue for personalized treatment of MUD.

Aberrant intrinsic functional brain topology in methamphetamine-dependent individuals after six-months of abstinence

Our aim was to explore the aberrant intrinsic functional topology in methamphetamine-dependent individuals after six months of abstinence using resting-state functional magnetic imaging (rs-fMRI). Eleven methamphetamines (MA) abstainers who have abstained for six months and eleven healthy controls (HC) were recruited for rs-fMRI examination. The graph theory and functional connectivity (FC) analysis were employed to investigate the aberrant intrinsic functional brain topology between the two groups at multiple levels. Compared with the HC group, the characteristic shortest path length ($ {L}_{p} $) showed a significant decrease at the global level, while the global efficiency ($ {E}_{glob} $) and local efficiency ($ {E}_{loc} $) showed an increase considerably. After FDR correction, we found significant group differences in nodal degree and nodal efficiency at the regional level in the ventral attentional network (VAN), dorsal attentional network (DAN), somatosensory network (SMN), visual network (VN) and default mode network (DMN). In addition, the NBS method presented the aberrations in edge-based FC, including frontoparietal network (FPN), subcortical network (SCN), VAN, DAN, SMN, VN and DMN. Moreover, the FC of large-scale functional brain networks revealed a decrease within the VN and SCN and between the networks. These findings suggest that some functions, e.g., visual processing skills, object recognition and memory, may not fully recover after six months of withdrawal. This leads to the possibility of relapse behavior when confronted with MA-related cues, which may contribute to explaining the relapse mechanism. We also provide an imaging basis for revealing the neural mechanism of MA-dependency after six months of abstinence.

Does chronic use of amphetamine-type stimulants impair interference control? - A meta-analysis

In substance use and addiction, inhibitory control is key to ignoring triggers, withstanding craving and maintaining abstinence. In amphetamine-type stimulant (ATS) users, most research focused on behavioral inhibition, but largely neglected the equally important subdomain of cognitive interference control. Given its crucial role in managing consumption, we investigated the relationship between interference control and chronic ATS use in adults. A database search (Pubmed & Web of Science) and relevant reviews were used to identify eligible studies. Effect sizes were estimated with random effects models. Subgroup, meta-regression, and sensitivity analyses explored heterogeneity in effect sizes. We identified 61 studies (53 datasets) assessing interference control in 1873 ATS users and 1905 controls. Findings revealed robust small effect sizes for ATS-related deficits in interference control, which were mainly seen in methamphetamine, as compared to MDMA users. The differential effects are likely due to tolerance-induced dopaminergic deficiencies (presumably most pronounced in methamphetamine users). Similarities between different ATS could be due to noradrenergic deficiencies; but elucidating their functional role in ATS users requires further/more research.

Goofballing of Opioid and Methamphetamine: The Science Behind the Deadly Cocktail

Globally, millions of people suffer from various substance use disorders (SUD), including mono-and polydrug use of opioids and methamphetamine. Brain regions such as the cingulate cortex, infralimbic cortex, dorsal striatum, nucleus accumbens, basolateral and central amygdala have been shown to play important roles in addiction-related behavioral changes. Clinical and pre-clinical studies have characterized these brain regions and their corresponding neurochemical changes in numerous phases of drug dependence such as acute drug use, intoxication, craving, withdrawal, and relapse. At present, many studies have reported the individual effects of opioids and methamphetamine. However, little is known about their combined effects. Co-use of these drugs produces effects greater than either drug alone, where one decreases the side effects of the other, and the combination produces a prolonged intoxication period or a more desirable intoxication effect. An increasing number of studies have associated polydrug abuse with poorer treatment outcomes, drug-related deaths, and more severe psychopathologies. To date, the pharmacological treatment efficacy for polydrug abuse is vague, and still at the experimental stage. This present review discusses the human and animal behavioral, neuroanatomical, and neurochemical changes underlying both morphine and methamphetamine dependence separately, as well as its combination. This narrative review also delineates the recent advances in the pharmacotherapy of mono- and poly drug-use of opioids and methamphetamine at clinical and preclinical stages.

Candidate Chinese Herbal Medicine Alleviates Methamphetamine Addiction via Regulating Dopaminergic and Serotonergic Pathways

Methamphetamine (METH) addiction and its induced mental disorders have become a severe worldwide problem. A candidate Chinese herbal medicine (CCHM) in our lab had therapeutic effects on METH-induced locomotor sensitization, however, its chemical and pharmacological profiles remain to be elucidated. The current study aimed to investigate the effect of CCHM on conditioned place preference (CPP) induced by METH and screen the main active ingredients and key targets by using network pharmacology and molecular docking methods. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment, Gene ontology (GO) analysis and protein-protein interaction (PPI) network were performed to discover the potential mechanisms. Results showed that CCHM could significantly inhibit METH-induced CPP behaviors in mice. A total of 123 components and 43 targets were screened. According to the network pharmacology analysis, ten hub targets including D(2) dopamine receptor (DRD2) and 5-hydroxytryptamine receptor 3A (HTR3A) were screened. GO analysis and KEGG enrichment indicated that mechanisms of CCHM treatment of METH addiction were related to multiple pathways such as dopaminergic synapse and serotoninergic synapse. Western blot results showed that the protein expressions of DRD2 in nucleus accumbens and prefrontal cortex were significantly decreased in METH group, while the protein expressions of HTR3A were significantly increased. These changes caused by METH could be prevented by CCHM pretreatment. The results of molecular docking displayed that the five active ingredients such as (S)-Scoulerine, Hyndarin, and Beta-Sitosterol had good affinities with DRD2 and HTR3A. In conclusion, this study constructed the CCHM's pharmacologic network for treating METH addiction based on the method of network analysis and experimental verification, and analyzed its major active ingredients and potential targets, indicating a new direction for further revealing its mechanisms of effect on METH addiction.

The Higher Parietal Cortical Thickness in Abstinent Methamphetamine Patients Is Correlated With Functional Connectivity and Age of First Usage

Aim

This study aimed to explore the changes of cortical thickness in abstinent methamphetamine (MA) patients compared with healthy controls.

Materials and Methods

Three-tesla structural and functional magnetic resonance imaging (MRI) was obtained from 38 abstinent methamphetamine-dependent (AMD) patients and 32 demographically equivalent healthy controls. The cortical thickness was assessed using FreeSurfer software. General linear model was used to get brain regions with significant different cortical thickness between groups (p < 0.05, Monte Carlo simulation corrected). The mean cortical thickness value and functional connectivity with all other brain regions was extracted from those significant regions. Moreover, correlation coefficients were calculated in the AMD group to assess the relations between the mean cortical thickness, functional connectivity and age when they first took MA and the duration of both MA use and abstinence.

Results

The AMD group showed significant cortical thickness increase in one cluster located in the parietal cortex, including right posterior central gyrus, supramarginal gyrus, and superior parietal lobule. In addition, cortical thickness values of those regions were all significant and negatively correlated with the age when patients first used MA. The cortical thickness of right posterior gyrus were positively correlated with its functional connectivities with left middle frontal gyrus and both left and right medial orbitofrontal gyrus.

Conclusion

The higher cortical thickness in the parietal cortex of the AMD group is in agreement with findings in related studies of increased glucose metabolism and gray matter volume. Importantly, the negative correlation between parietal cortical thickness and age of first MA suggested that adolescent brains are more vulnerable to MA’s neurotoxic effect.

Effects of Aerobic Exercise on Cognitive Function in Women With Methamphetamine Dependence in a Detoxification Program in Tianjin, China: A Randomized Controlled Trial

BACKGROUND

Cognitive impairment is prevalent among individuals, especially women, with methamphetamine dependence. Although aerobic exercise has been shown to affect cognitive function in humans and animals, few related studies have focused on subjects with methamphetamine dependence.

PURPOSE

The aim of this study was to assess the detoxification-related effects of aerobic exercise on cognitive function in women with methamphetamine dependence.

METHODS

A randomized controlled trial was used with 98 women with methamphetamine dependence undergoing a detoxification program at a mental hospital. The women were distributed using a computer-generated grouping random method into either the study or control group. The investigator conducting the baseline questionnaire, the neuropsychologist assessing the cognitive function, and the data analyst were blinded to group assignment. In addition to hospital routine care, the study group received an aerobic exercise intervention for 3 months. The control group only received hospital routine care. Attention and working memory were measured using the Trail Making Test and Digit Span Test, verbal memory was measured using Logical Memory (LM) and Memory for Persons Data (MPD), and executive function was measured using the Color-Word Stroop Test.

RESULTS

Forty-nine participants were randomized into each group, and the valid data of 43 participants in the study group and 46 in the control group were analyzed. The study group showed significantly more improvement over time in terms of Digit Span Test, Trail Making Test, LM-delayed, MPD-5 minutes delayed, MPD-30 minutes delayed, and Color-Word Stroop Test than the control group (p < .05). LM-immediate and MPD-immediate scores showed that the effects of time and the interaction between time and group were significant but that the main effect of group was not.

CONCLUSIONS/IMPLICATIONS FOR PRACTICE

Women undergoing detoxification for methamphetamine dependence may practice aerobic exercise to improve attention, working memory, executive function, and parts of verbal memory. Aerobic exercise may be incorporated into detoxification treatment programs to facilitate the recovery of cognitive functions in women.

Apathy is associated with poorer abstinence self-efficacy in individuals with methamphetamine dependence

•

Used an apathy composite T-score approach validated in methamphetamine-dependence.

•

Apathy, above other factors, associated with poorer drug abstinence self-efficacy.

•

Methamphetamine use characteristics unrelated to drug abstinence self-efficacy.

•

Social peer pressure was riskiest situation for potential methamphetamine relapse.

Background

Confidence in one’s ability to achieve and maintain drug abstinence (i.e., abstinence self-efficacy) is a strong predictor of substance use treatment outcomes. Neurobehavioral factors that may interfere with abstinence self-efficacy are less well established, particularly in methamphetamine (METH). This study investigated whether apathy, which is highly prevalent during active METH use and periods of abstinence, influences abstinence self-efficacy among METH dependent individuals.

Methods

Sixty-six participants with lifetime METH dependence and METH abuse/METH dependence diagnoses within the last 18 months (mean age [SD] = 39.5 years [10.7]), and no severe psychiatric or neurological diseases, completed the Methamphetamine Self-Efficacy Scale (MSES), alongside a comprehensive neurobehavioral evaluation. The MSES presents six situations that may lead to relapse and collects self-report ratings for two subscales: “Confidence” (i.e., confidence in one’s ability to abstain from using METH, or METH abstinence self-efficacy) and “Temptation” (i.e., how tempted one is to use METH) with regard to each situation. Apathy was measured using a composite T-score comprised of items and scales from three well-validated, self-report assessments.

Results

Multivariable linear regression found that higher Apathy T-scores were significantly associated with lower Confidence ratings (i.e., poorer METH abstinence self-efficacy; p < .05), independent of potentially relevant factors (e.g., Temptation to use METH, comorbid HIV disease, and neurocognitive impairment).

Conclusions

Elevated apathy may adversely impact one’s confidence to abstain from METH use. Findings highlight the importance of addressing apathy in order to improve METH abstinence self-efficacy, which may subsequently increase the likelihood of successful METH treatment outcomes.

The relationship between duration of abstinence and gray-matter brain structure in chronic methamphetamine users

Background: Brain structural findings in chronic methamphetamine users have been inconsistent. Identifying contributing influences (e.g., sex, abstinence duration) can help clarify the clinical course of recovery.Objectives: We studied the effects of long-term methamphetamine abstinence on gray-matter volume. Our hypothesis was that smaller volume early in abstinence would precede long-term recovery.Methods: Individuals who used methamphetamine (≥100 g lifetime use, mandated to residential treatment for methamphetamine-positive urine; 40 men, 21 women), undergoing supervised abstinence (men: 12-400 days; women: 130-594 days), were compared to healthy controls (49 men, 36 women) using T1-weighted MRI. Volumes of orbitofrontal, anterior cingulate and parietal cortex, hippocampus, and striatum were measured using Freesurfer software. Associations of volumes with abstinence duration were tested in males and females separately because their abstinence times differed (121.5 ± 124.5 vs. 348.0 ± 128.6 days, p < 0.001); only males were studied in early abstinence. The General Linear Model was used to test effects of abstinence duration and group (methamphetamine users vs. controls).Results: In males, duration of abstinence was multivariate significant for gray-matter volumes (p = 0.017). Abstinence duration was associated with increases in volumes of the orbitofrontal and parietal cortices (ps = 0.031, 0.016) and hippocampi (ps = 0.044). Irrespective of abstinence, male methamphetamine users had smaller hippocampi than male controls (p = 0.008). Females showed no significant effects of group or abstinence.Conclusions: In males, abstinence from methamphetamine appears to result in volumetric increases in regions important for cognitive function, which may affect recovery during the course of treatment. Data from the period of early abstinence are required to evaluate volumetric changes in females.

Neurocognitive impairment and gray matter volume reduction in HIV-infected patients

Although neuropsychological studies of human immunodeficiency virus (HIV)-infected patients have demonstrated heterogeneity in neurocognitive impairment and neuroimaging studies have reported diverse brain regions affected by HIV, it remains unclear whether individual differences in neurocognitive impairment are underpinned by their neural bases. Here, we investigated spatial distribution patterns of correlation between neurocognitive function and regional gray matter (GM) volume across patients with HIV. Thirty-one combination antiretroviral therapy-treated HIV-infected Japanese male patients and 33 age- and sex-matched healthy controls were included in the analysis after strict exclusion criteria, especially for substance use. Fifteen neurocognitive tests were used, and volumetric magnetic resonance imaging was performed. We used voxel-based morphometry to compare GM volume between groups and identify regional GM volumes that correlated with neurocognitive tests across patients. Using the Frascati criteria, 10 patients were diagnosed with asymptomatic neurocognitive impairment, while the others were not diagnosed with HIV-associated neurocognitive disorders. Patients showed a significantly lower performance in five neurocognitive tests as well as significantly reduced GM volume relative to controls, with volume-reduced regions spread diffusely across the whole brain. Different aspects of neurocognitive impairment (i.e., figural copy, finger tapping, and Pegboard) were associated with different GM regions. Our findings suggest a biological background constituting heterogeneity of neurocognitive impairment in HIV infection and support the clinical importance of considering individual differences for tailor-made medicine for people living with HIV.