Gray matter volume showed dynamic alterations in methamphetamine users at 6 and 12months abstinence: A longitudinal voxel-based morphometry study

Neuroimaging mechanisms in short-term heroin- and methamphetamine-abstinent users: Similarities and differences

Heroin and methamphetamine cause great damage to individuals and society. However, numerous withdrawal mechanisms remain unidentified. In this study, 19 heroin short-term abstinent (HSTA) patients, 20 methamphetamine short-term abstinent (MSTA) patients, and 27 healthy controls (HCs) were scanned using multimodal magnetic resonance imaging. Degraded nodes of fiber tracts were identified using automated fiber quantification. Voxel- and surface-based morphometric measurements were performed to determine the gray matter volume and cortical thickness. The MSTA and HSTA groups had abnormal diffusion metrics in a variety of bilateral corticospinal tract (CST) and left superior longitudinal tract (SLT) nodes compared with the HC group. The MSTA patients reported more severely disrupted diffusion metrics in certain nodes of the bilateral anterior thalamic radiation and left inferior fronto-occipital tract than the HSTA patients. The MSTA and HSTA groups exhibited identical cortical damage in the fusiform and superior temporal gyri, as well as in the superior frontal gyrus, posterior cerebellum, and precentral gyrus. Extensive differences in gray matter lesions were observed between the MSTA and HSTA groups. Neuroimaging mechanisms of short-term abstinence may aid in the development of rehabilitation strategies.

Nanowired Delivery of Mesenchymal Stem Cells with Antioxidant Compound H-290/51 Reduces Exacerbation of Methamphetamine Neurotoxicity in Hot Environment

Military personnel are often exposed to hot environments either for combat operations or peacekeeping missions. Hot environment is a severe stressful situation leading to profound hyperthermia, fatigue and neurological impairments. To avoid stressful environment, some people frequently use methamphetamine (METH) or other psychostimulants to feel comfortable under adverse situations. Our studies show that heat stress alone induces breakdown of the blood-brain barrier (BBB) and edema formation associated with reduced cerebral blood flow (CBF). On the other hand, METH alone induces hyperthermia and neurotoxicity. These effects of METH are exacerbated at high ambient temperatures as seen with greater breakdown of the BBB and brain pathology. Thus, a combination of METH use at hot environment may further enhance the brain damage-associated behavioral dysfunctions. METH is well known to induce severe oxidative stress leading to brain pathology. In this investigation, METH intoxication at hot environment was examined on brain pathology and to explore suitable strategies to induce neuroprotection. Accordingly, TiO₂-nanowired delivery of H-290/51 (150 mg/kg, i.p.), a potent chain-breaking antioxidant in combination with mesenchymal stem cells (MSCs), is investigated in attenuating METH-induced brain damage at hot environment in model experiments. Our results show that nanodelivery of H-290/51 with MSCs significantly enhanced CBF and reduced BBB breakdown, edema formation and brain pathology following METH exposure at hot environment. These observations are the first to point out that METH exacerbated brain pathology at hot environment probably due to enhanced oxidative stress, and MSCs attenuate these adverse effects, not reported earlier.

Effects of Aerobic Exercise on Markers of Brain Injury in Methamphetamine-Dependent Individuals: A Randomized Controlled Trial

Objective: Drug dependence has become a major global public health problem. This study aimed to investigate the effects of moderate-intensity aerobic exercise on the blood−brain barrier and neurological damage in methamphetamine (MA)-dependent individuals. Methods: MA-dependent individuals (all males) were recruited and randomly divided into MA exercise group (MAE) and MA control group (MAC) by using random number table method. The MAE group underwent 12 weeks of moderate-intensity aerobic exercise, and the MAC group underwent conventional detoxification. The Neurofilament light chain (NfL), S100 calcium binding protein b (S100b), and Neuron-Specific Enolase (NSE) levels in the blood of MA-dependent individuals were measured before and after the exercise intervention. Results: After the exercise intervention was implemented, the amount of change in NfL in the plasma of the MAE (1.75 ± 1.40) group was significantly different from that of the MAC (0.60 ± 1.21) group (p < 0.01); the amount of change in NSE in the serum of the MAE [−1.51 (−3.99~0.31)] group was significantly different from that of the MAC [0.03 (−1.18~1.16)] group (p < 0.05); and the amount of change in S100b in the serum of the MAE [0.66 (0.40~0.95)] group was not significantly different from that of the MAC (0.60 (0.21~1.04)) group (p > 0.05). Conclusion: This study showed that 12 weeks of moderate-intensity aerobic exercise treatment significantly promoted the recovery of blood−brain barrier and neurological damage in MA-dependent patients compared with conventional withdrawal.

Common gray matter loss in the frontal cortex in patients with methamphetamine-associated psychosis and schizophrenia

BACKGROUND AND HYPOTHESIS

Methamphetamine (MA)-associated psychosis has become a public concern. However, its mechanism is not clear. Investigating similarities and differences between MA-associated psychosis and schizophrenia in brain alterations would be informative for neuropathology.

STUDY DESIGN

This study compared gray matter volumes of the brain across four participant groups: healthy controls (HC, n = 53), MA users without psychosis (MA, n = 22), patients with MA-associated psychosis (MAP, n = 34) and patients with schizophrenia (SCZ, n = 33). Clinical predictors of brain alterations, as well as association of brain alterations with psychotic symptoms and attention impairment were further investigated.

STUDY RESULTS

Compared with the HC, the MAP and the SCZ showed similar gray matter reductions in the frontal cortex, particularly in prefrontal areas. Moreover, a stepwise extension of gray matter reductions was exhibited across the MA - MAP - SCZ. Duration of abstinence was associated with regional volumetric recovery in the MAP, while this amendment in brain morphometry was not accompanied with symptom's remission. Illness duration of psychosis was among the predictive factors of regional gray matter reductions in both psychotic groups. Volume reductions were found to be associated with attention impairment in the SCZ, while this association was reversed in the MAP in frontal cortex.

CONCLUSIONS

This study suggested MA-associated psychosis and schizophrenia had common neuropathology in cognitive-related frontal cortices. A continuum of neuropathology between MA use and schizophrenia was tentatively implicated. Illness progressions and glial repairments could both play roles in neuropathological changes in MA-associated psychosis.

Structural and functional brain recovery in individuals with substance use disorders during abstinence: A review of longitudinal neuroimaging studies

BACKGROUND

Neuroimaging studies reveal structural and functional including neurochemical brain abnormalities in individuals with substance use disorders compared to healthy controls. However, whether and to what extent such dysfunction is reversible with abstinence remains unclear, and a review of studies with longitudinal within-subject designs is lacking. We performed a systematic review of longitudinal neuroimaging studies to explore putative brain changes associated with abstinence in treatment-seeking individuals with substance use disorders.

METHODS

Following PRISMA guidelines, we examined articles published up to May 2021 that employed a neuroimaging technique and assessed neurobiological recovery in treatment-seeking participants at a minimum of two time-points separated by a period of abstinence (longer than 24 h apart) or significant reduction in drug use.

RESULTS

Forty-five studies met inclusion criteria. Encouragingly, in this limited but growing literature, the majority of studies demonstrated at least partial neurobiological recovery with abstinence. Structural recovery appeared to occur predominantly in frontal cortical regions, the insula, hippocampus, and cerebellum. Functional and neurochemical recovery was similarly observed in prefrontal cortical regions but also in subcortical structures. The onset of structural recovery appears to precede neurochemical recovery, which begins soon after cessation (particularly for alcohol); functional recovery may require longer periods of abstinence.

CONCLUSIONS

The literature is still growing and more studies are warranted to better understand abstinence-mediated neural recovery in individuals with substance use disorders. Elucidating the temporal dynamics between neuronal recovery and abstinence will enable evidence-based planning for more effective and targeted treatment of substance use disorders, potentially pre-empting relapse.

Brain morphometric abnormalities and their associations with affective symptoms in males with methamphetamine use disorder during abstinence

BACKGROUND

Methamphetamine (METH) use induces neurotoxic effects in brain structures and affective symptoms that persist during abstinence. However, the brain morphometry of individuals with METH use disorder (MUD) remains unclear, as well as their associations with affective symptoms during abstinence.

METHODS

Forty-eight abstinent males with MUD and 66 age-, sex-, and education-matched healthy controls (HCs) underwent high-resolution T1-weighted magnetic resonance imaging. Cortical thickness, surface area, volume, local gyrification index (LGI), and subcortical volume were obtained with FreeSurfer software. Brain morphometry differences between groups and their associations with affective symptoms and drug abuse history within the males with MUD were examined, with intracranial volume, age, and years of education as covariates.

RESULTS

Compared with the HCs, the individuals with MUD showed a significantly higher LGI in the right cuneus gyrus, left lingual gyrus, bilateral supramarginal gyrus, right inferior parietal gyrus (IPG), and right dorsal anterior cingulate cortex (clusterwise p < 0.05, Monte Carlo-corrected), as well as a smaller volume of the left nucleus accumbens (NAcc) (p < 0.05, FDR-corrected). However, there were no significant group differences in cortical thickness, area or volume. In addition, the LGI in the right IPG was positively associatedwith the severity of depression and anxiety symptoms in MUDs (p < 0.05, FDR-corrected).

CONCLUSION

Brain morphometric abnormalities in abstinent males with MUD were characterized by hypergyrification across multiple mid-posterior brain regions anda smaller volume of the left NAcc.Gyrification of the right IPG may be a potential neural substrate underlying the affective symptoms experienced by MUDs during abstinence.

Electrophysiological indexes for impaired response inhibition and salience attribution in substance (stimulants and depressants) use disorders: A meta-analysis

The impairment of inhibitory control and reward system is the core feature underlying substance use disorder (SUD). Previous studies suggested that it can be regarded as impaired response inhibition and salience attribution syndrome (iRISA). The neural substrates of the two deficit functions were widely investigated in neuroimaging studies, and the impaired prefrontal cortex, limbic-orbitofrontal network, and fronto-insular-parietal network were observed. Previous Event-related potential (ERP) studies were also conducted to explore EEG indexes related to abnormal brain function. In the current meta-analysis, we aimed to explore the consistency of ERP indexes that can reflect the two aberrant processes: P300/slow potential (SP) for salience attribution and Error-related negativity (ERN)/Nogo-N200/Nogo-P300 for inhibitory control and conflict monitoring. Subgroup analyses for drug type and drug use conditions were also conducted. According to the 60 research studies, we found significantly enhanced drug-cue-induced P300 amplitude and attenuated Nogo-N200 amplitude in SUD individuals relative to Healthy control (HC), which supports the dual model. Moreover, the drug-cue-induced P300 displayed time-dependence recovery, suggesting a potential index for treatment evaluation. In conclusion, drug-cue-induced P300 and Nogo-N200 demonstrated high consistency, and the drug-cue-induced P300 can be used to track the changes of functional recovery for SUD. The integration of the two ERP components could be regarded as a potential biomarker for SUD, which may provide a new insight for clinical treatment and investigation.

Lack of longitudinal changes in cognition in individuals with methamphetamine use disorder during the first 6 weeks after commencing treatment

Background: Methamphetamine use disorder (MUD) associates with cognitive impulsivity deficits. However, few studies have examined longitudinal changes in cognition, and it remains unclear if deficits resolve during early recovery.Objectives: To compare: (1) cognitive function of individuals with MUD at treatment onset and six-weeks later with controls tested over the same period; (2) cognitive changes in MUD-individuals who remained abstinent versus relapsed.Method: We recruited 108 participants meeting DSM-IV-TR criteria for methamphetamine dependence (81 males) and 50 demographically matched controls (38 males); 77 methamphetamine- dependent participants (59 males) and 48 controls (36 males) were retained at follow-up. We administered response inhibition, delay discounting and uncertainty-based decision-making tests at both endpoints. Relapse was defined as methamphetamine concentrations >0.4 ng/mg at follow-up in hair toxicology.Results: We found a significant time-by-group interaction on uncertainty-based decision-making (effect size: η² = .05), although post-hoc tests to disentangle this interaction yielded inconclusive results (p-range = .14-.40; BF₁₀-range = 0.43-1.67). There were no significant time-by-group interactions on response inhibition or delay discounting, with the former likely a null effect (η²-interaction = .003 and .02; BF_incl = 0.23 and 0.71). There were no significant differences in cognitive recovery between individuals who maintained abstinence (n = 12) versus relapsed (n = 65) (η²-range = .003-.04), although evidence was inconclusive toward whether findings reflected true null effects (BF_incl-range = 0.33-0.75).Conclusion: We did not find evidence that MUD-related cognitive impulsivity deficits improve beyond practice effects over 6 weeks. Findings do not support previous, albeit conflicting, evidence of early recovery of cognitive deficits in MUD.

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.

Cortical Thickness Changes in Chronic Ketamine Users

Background: Previous studies have examined the effects of long-term ketamine use on gray matter volume. But it is unclear whether chronic ketamine use alters cortical thickness and whether cortical thickness changes in chronic ketamine users are associated with cognitive deficits observed in chronic ketamine users. Methods: Here, 28 chronic ketamine users and 30 healthy controls (HCs) were recruited. Cortical morphometry based on Computational Anatomy Toolbox (CAT12) was used to measure cortical thickness. Cognitive performance was measured by MATRICS Consensus Cognitive Battery (MCCB). Two-sample t-test was used to assess differences in cortical thickness and cognitive performance between the two groups. Partial correlation analysis was used for assessing correlations between cortical thickness changes and clinical characteristics, cognitive performance in chronic ketamine users. Results: Chronic ketamine users exhibited significantly reduced cortical thickness in frontal, parietal, temporal, and occipital lobes compared to HC [false discovery rate (FDR) corrected at p < 0.05]. In chronic ketamine users, the average quantity (g) of ketamine use/day was negatively correlated with cortical thickness in the left superior frontal gyrus (SFG), right caudal middle frontal gyrus (MFG), and right paracentral lobule. The frequency of ketamine use (days per week) was negatively correlated with cortical thickness in the left isthmus cingulate cortex. Duration of ketamine use (month) was negatively correlated with cortical thickness in the left precentral gyrus. The chronic ketamine users showed significantly poorer cognitive performance on the working memory (P = 0.009), visual learning (P = 0.009), speed of processing (P < 0.000), and Matrics composite (P = 0.01). There was no correlation between scores of domains of MCCB and reduced cortical thickness. Conclusion: The present study observed reduced cortical thickness in multiple brain areas, especially in the prefrontal cortex (PFC) in chronic ketamine users. Dose, frequency, and duration of ketamine use was negatively correlated with cortical thickness of some brain areas. Our results suggest that chronic ketamine use may lead to a decrease of cortical thickness. But the present study did not observe any correlation between reduced cortical thickness and decreased cognitive performance in chronic ketamine users.

Severe Encephalatrophy and Related Disorders From Long-Term Ketamine Abuse: A Case Report and Literature Review

Ketamine is a glutamate N-methyl D-aspartate receptor antagonist and an anaesthetic agent that has been effectively used to treat depression. However, ketamine has also been increasingly used for recreational purposes. The dissociative side-effects of ketamine use, such as hallucinations, are the reason for abuse. Additionally, long-term ketamine abuse has been highly associated with liver-gallbladder and urinary symptoms. The present study reports the case of a 28-year-old young male adult with an 8-year history of daily inhalation of ketamine. We investigated the association between ketamine abuse and the mechanism of its adverse effects, particularly encephalatrophy, and attempted to find a link between these disorders. These results would help us to better understand ketamine usage, ketamine abuse effects and the addictive mechanism. To the best of our knowledge, the present case is the first report of severe brain atrophy related to ketamine abuse. Details of the patient are presented and the mechanism of the encephalatropy-associated ketamine abuse is discussed. Furthermore, organ dysfunction following chronic ketamine abuse may indicate that the side effects are the result of comprehensive action on multiple regions in the brain.

Inflammation but not programmed cell death is activated in methamphetamine-dependent patients: Relevance to the brain function

Animal studies have shown that methamphetamine (MA) induces neurodegeneration through programmed cell death, however, the effects of MA on human brain and the extent of induced neural degeneration is not well understood. Given that the dose and duration of MA administration differ in animals and humans, we evaluated MA effects on active users considering brain damage mechanisms. Nineteen active MA-dependent patients and 18 healthy controls performed the color-word Stroop task, during fMRI and their blood samples were collected. Human enzyme-linked immunosorbent assays (ELISA) and quantitative PCR were applied to measure circulating proteins and miRNAs involved in various programmed cell death pathways (apoptosis, necroptosis, and autophagy), brain damage and neuroinflammation. Results showed the performance deficit in color-word Stroop task in MA abusers as well as higher activations of the right inferior and middle temporal gyri detected by fMRI. Structural MRI revealed increased white matter volume in MA-dependent patients in the superior and medial frontal gyri, and left/right middle temporal gyrus. Molecular analyses detected no significant differences in the plasma levels of the studied proteins and miRNAs of MA-dependent patients and controls except the higher levels of MBP, S100B, and TNFα in MA abusers. Results showed that MA induced physiological and structural changes accompanied by inflammation and release of damage-associated molecules in MA-dependent patients.

Executive function moderates naltrexone effects on methamphetamine-induced craving and subjective responses

Background: Emerging evidence suggests that opioid receptor antagonists, such as naltrexone, are effective pharmacotherapies for alcohol, opioid, and possibly stimulant use disorders. It is posited that naltrexone exerts its effects, in part, by increasing functional connectivity between neural reward circuitry and frontal systems implicated in executive function. Yet no studies had examined whether executive function moderates these effects. Objectives: This study examined whether a composite measure of executive function (EF) moderates the effect of naltrexone on craving for methamphetamine and subjective responses following infusion of the drug. Methods: Individuals with methamphetamine use disorder (N = 30; 27% female) completed baseline neurocognitive assessments of premorbid and executive function, and an executive function factor was computed. Participants then underwent a randomized, double-blind, cross-over study of titration with naltrexone and placebo. Participants then received a 30-mg intravenous methamphetamine infusion and completed subjective response questionnaires at 8 times in the 120 minutes post-infusion. Results: Multilevel mixed models indicated a significant EF × medication interaction, reflecting greater effects of naltrexone to decrease "desire to access the drug", "want more of the drug", "crave the drug", "feel drug effects" and "feel high" in participants with low EF compared to those with high EF (Bs = .36-1.29, SEs = .14-.17, ps<0.01). These effects remained significant after controlling for premorbid cognitive functioning, baseline responses to methamphetamine, severity of methamphetamine use, and methamphetamine-related functional problems. Conclusion: Naltrexone may be especially effective in methamphetamine-dependent individuals with low EF. Neuropsychological assessments may also provide predictive clinical utility not captured by traditional measures of substance use severity.

Higher impulsivity and lower grey matter volume in the bilateral prefrontal cortex in long-term abstinent individuals with severe methamphetamine use disorder

BACKGROUND

Previous studies have shown that grey matter volume (GMV) might be lower in individuals with methamphetamine use disorder and that dynamic alterations in selected brain regions might appear in individuals after short-term abstinence. However, the GMV of brains in these individuals after long-term abstinence is poorly understood. Moreover, individuals with severe methamphetamine use disorder have been considered to have high levels of impulsivity, but the biological mechanism is still unclear.

METHODS

In this study, the impulsivity of all participants was assessed using the Barratt Impulsiveness Scale (BIS-11). Using voxel-based morphometry (VBM) in conjunction with statistical parametric mapping on structural magnetic resonance images, the GMVs of the whole brain were compared among 32 drug-naïve healthy controls (HC) and 40 individuals with severe methamphetamine use disorder who had been abstinent for at least 20 months (SMUD-A).

RESULTS

We observed significantly higher BIS-11 impulsivity scores and lower GMV in the bilateral superior frontal cortex of SMUD-A individuals than in those of control subjects. The impulsivity score was negatively correlated with GMV in the right superior frontal cortex.

CONCLUSIONS

These findings offer novel evidence with respect to the impulsivity trait and brain GMV feature in long-term abstinent individuals with severe methamphetamine use disorder. Moreover, our findings suggest that lower GMV in the right superior frontal cortex might reflect a trait marker of higher impulsivity in this population.

Disrupted brain network dynamics and cognitive functions in methamphetamine use disorder: insights from EEG microstates

BACKGROUND

Dysfunction in brain network dynamics has been found to correlate with many psychiatric disorders. However, there is limited research regarding resting electroencephalogram (EEG) brain network and its association with cognitive process for patients with methamphetamine use disorder (MUD). This study aimed at using EEG microstate analysis to determine whether brain network dynamics in patients with MUD differ from those of healthy controls (HC).

METHODS

A total of 55 MUD patients and 27 matched healthy controls were included for analysis. The resting brain activity was recorded by 64-channel electroencephalography. EEG microstate parameters and intracerebral current sources of each EEG microstate were compared between the two groups. Generalized linear regression model was used to explore the correlation between significant microstates with drug history and cognitive functions.

RESULTS

MUD patients showed lower mean durations of the microstate classes A and B, and a higher global explained variance of the microstate class C. Besides, MUD patients presented with different current density power in microstates A, B, and C relative to the HC. The generalized linear model showed that MA use frequency is negatively correlated with the MMD of class A. Further, the generalized linear model showed that MA use frequency, scores of Two-back task, and the error rate of MA word are correlated with the MMD and GEV of class B, respectively.

CONCLUSIONS

Intracranial current source densities of resting EEG microstates are disrupted in MUD patients, hence causing temporal changes in microstate topographies, which are correlated with attention bias and history of drug use.

Gray-matter structure in long-term abstinent methamphetamine users

BACKGROUND

Previous studies of brain structure in methamphetamine users have yielded inconsistent findings, possibly reflecting small sample size and inconsistencies in duration of methamphetamine abstinence as well as sampling and analyses methods. Here we report on a relatively large sample of abstinent methamphetamine users at various stages of long-term abstinence.

METHODS

Chronic methamphetamine users (n = 99), abstinent from the drug ranging from 12 to 621 days, and healthy controls (n = 86) received T1-weighted structural magnetic resonance imaging brain scans. Subcortical and cortical gray-matter volumes and cortical thickness were measured and the effects of group, duration of abstinence, duration of methamphetamine use and onset age of methamphetamine use were investigated using the Freesurfer software package.

RESULTS

Methamphetamine users did not differ from controls in gray-matter volumes, except for a cluster in the right lateral occipital cortex where gray-matter volume was smaller, and for regions mainly in the bilateral superior frontal gyrui where thickness was greater. Duration of abstinence correlated positively with gray-matter volumes in whole brain, bilateral accumbens nuclei and insulae clusters, and right hippocampus; and with thickness in a right insula cluster. Duration of methamphetamine use correlated negatively with gray-matter volume and cortical thickness of a cluster in the right lingual and pericalcarine cortex.

CONCLUSIONS

Chronic methamphetamine use induces hard-to-recover cortical thickening in bilateral superior frontal gyri and recoverable volumetric reduction in right hippocampus, bilateral accumbens nuclei and bilateral cortical regions around insulae. These alternations might contribute to methamphetamine-induced neurocognitive disfunctions and reflect a regional specific response of the brain to methamphetamine.

Aberrant Resting-State Cerebellar-Cerebral Functional Connectivity in Methamphetamine-Dependent Individuals After Six Months Abstinence

BACKGROUND

Structural and functional alterations in the cerebellum have been consistently reported in addiction literatures. However, evidence implicating the resting-state cerebellar-cerebral functional connectivity in methamphetamine (MA) use disorder still remains limited.

METHODS

Resting-state functional magnetic resonance imaging (fMRI) scans were obtained from 34 MA dependent individuals with about six months abstinence and 31 healthy controls (well matched for age, gender and education) in this study. Seed-based functional connectivity analysis was employed to investigate the differences in cerebellar-cerebral functional connectivity between two groups. The correlations between significant functional connectivity and each clinical characteristic were also explored.

RESULTS

Compared to healthy controls, MA dependent individuals showed disrupted functional connectivity between the cerebellum and several cerebral functional networks, including the default-mode, affective-limbic, and sensorimotor networks. Within the MA group, functional connectivity of the right cerebellar lobule VI-precuneus coupling was negatively correlated with addiction severity.

CONCLUSION

The present study suggests that cerebellar dysfunction, in particular aberrant cerebellar-cerebral functional connectivity, might involve in neurobiological mechanism of MA dependence, which supply a potential target for therapeutic interventions in the future.

Bouncing back: Brain rehabilitation amid opioid and stimulant epidemics

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Frontoparietal event related potentials predict/track recovery.

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Frontostriatal functional magnetic resonance imaging signals predict/track recovery.

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Transcranial magnetic left prefrontal stimulation reduces craving and drug use.

Recent methamphetamine and opioid use epidemics are a major public health concern. Chronic stimulant and opioid use are characterized by significant psychosocial, physical and mental health costs, repeated relapse, and heightened risk of early death. Neuroimaging research highlights deficits in brain processes and circuitry that are linked to responsivity to drug cues over natural rewards as well as suboptimal goal-directed decision-making. Despite the need for interventions, little is known about (1) how the brain changes with prolonged abstinence or as a function of various treatments; and (2) how symptoms change as a result of neuromodulation. This review focuses on the question: What do we know about changes in brain function during recovery from opioids and stimulants such as methamphetamine and cocaine? We provide a detailed overview and critique of published research employing a wide array of neuroimaging methods – functional and structural magnetic resonance imaging, electroencephalography, event-related potentials, diffusion tensor imaging, and multiple brain stimulation technologies along with neurofeedback – to track or induce changes in drug craving, abstinence, and treatment success in stimulant and opioid users. Despite the surge of methamphetamine and opioid use in recent years, most of the research on neuroimaging techniques for recovery focuses on cocaine use. This review highlights two main findings: (1) interventions can lead to improvements in brain function, particularly in frontal regions implicated in goal-directed behavior and cognitive control, paired with reduced drug urges/craving; and (2) the targeting of striatal mechanisms implicated in drug reward may not be as cost-effective as prefrontal mechanisms, given that deep brain stimulation methods require surgery and months of intervention to produce effects. Overall, more studies are needed to replicate and confirm findings, particularly for individuals with opioid and methamphetamine use disorders.