White matter abnormalities correlating with memory and depression in heroin users under methadone maintenance treatment

Nucleus accumbens D1/D2 circuits control opioid withdrawal symptoms in mice

The nucleus accumbens (NAc) is the most promising target for drug use disorder treatment. Deep brain stimulation (DBS) of NAc is effective for drug use disorder treatment. However, the mechanisms by which DBS produces its therapeutic effects remain enigmatic. Here, we define a behavioral cutoff criterion to distinguish depressive-like behaviors and non-depressive-like behaviors in mice after morphine withdrawal. We identified a basolateral amygdala (BLA) to NAc D1 medium spiny neuron (MSN) pathway that controls depressive-like behaviors after morphine withdrawal. Furthermore, the paraventricular nucleus of thalamus (PVT) to NAc D2 MSN pathway controls naloxone-induced acute withdrawal symptoms. Optogenetically induced long-term potentiation with κ-opioid receptor (KOR) antagonism enhanced BLA to NAc D1 MSN signaling and also altered the excitation/inhibition balance of NAc D2 MSN signaling. We also verified that a new 50 Hz DBS protocol reversed morphine withdrawal-evoked abnormal plasticity in NAc. Importantly, this refined DBS treatment effectively alleviated naloxone-induced withdrawal symptoms and depressive-like behaviors and prevented stress-induced reinstatement. Taken together, the results demonstrated that input- and cell type-specific synaptic plasticity underlies morphine withdrawal, which may lead to novel targets for the treatment of opioid use disorder.

Effects of Abstinence From Opioid on Neuropsychological Performance in Men With Opioid Use Disorder: A Longitudinal Study

OBJECTIVES

Impairments in neuropsychological functioning (mainly memory, learning, attention, and executive functioning) among persons with long-term opioid use disorder (OUD) have been widely reported, with few studies suggesting that these are not permanent and can improve with abstinence. Thus, present study aimed to evaluate the neuropsychological functioning in persons with OUD and examine the effects of abstinence on the same over a period 8 weeks.

METHODS

A total of 50 patients with diagnosis of OUD as per the Diagnostic and Statistical Manual of Mental Disorders , Fifth Edition ( DSM-5 ) criteria underwent serial longitudinal neuropsychological assessments for executive functioning, attention and concentration, and verbal and nonverbal memory at baseline, 2 weeks, and 8 weeks of abstinence.

RESULTS

The mean performance scores representative of attention, concentration, verbal memory, and nonverbal memory showed significant improvement in the initial 2 weeks, and executive functioning showed significant improvement by 8 weeks of abstinence (all P 's < 0.01). A significant negative correlation was found between the duration of opioid use and performance on verbal memory tests (0.014), the frequency of intake per day and performance on nonverbal memory and executive functioning tests, and the severity of opioid dependence and performance on nonverbal memory test (0.019).

CONCLUSIONS

Neuropsychological functioning in certain domains was associated with the duration of opioid use, the frequency of daily opioid intake, and the severity of opioid dependence among persons with OUD at baseline. It showed significant improvement in domains of attention, concentration, verbal and nonverbal memory, and executive functions over a period of 8 weeks of abstinence.

The effect of repetitive transcranial magnetic stimulation on electroencephalography microstates of patients with heroin-addiction

The effects of transcranial magnetic stimulation in treating substance use disorders are gaining attention; however, most existing studies used subjective measures to examine the treatment effects. Objective electroencephalography (EEG)-based microstate analysis is important for measuring the efficacy of transcranial magnetic stimulation in patients with heroin addiction. We investigated dynamic brain activity changes in individuals with heroin addiction after transcranial magnetic stimulation using microstate indicators. Thirty-two patients received intermittent theta-burst stimulation (iTBS) over the left dorsolateral prefrontal cortex. Resting-state EEG data were collected pre-intervention and 10 days post-intervention. The feature values of the significantly different microstate classes were computed using a K-means clustering algorithm. Four EEG microstate classes (A-D) were noted. There were significant increases in the duration, occurrence, and contribution of microstate class A after the iTBS intervention. K-means classification accuracy reached 81.5%. The EEG microstate is an effective improvement indicator in patients with heroin addiction treated with iTBS. Microstates were examined using machine learning; this method effectively classified the pre- and post-intervention cohorts among patients with heroin addiction and healthy individuals. Using EEG microstate to measure heroin addiction and further exploring the effect of iTBS in patients with heroin addiction merit clinical investigation.

Chronic exposure to methadone impairs memory, induces microgliosis, astrogliosis and neuroinflammation in the hippocampus of adult male rats

Methadone is a centrally-acting synthetic opioid analgesic widely used in methadone maintenance therapy (MMT) programs throughout the world. Given its neurotoxic effects, particularly on the hippocampus, this study aims to address the behavioral and histological alterations in the hippocampus associated with methadone administration. To do so, twenty-four adult male albino rats were randomized into two groups, methadone treatment and control. Methadone was administered subcutaneously (2.5-10 mg/kg) once a day for two consecutive weeks. A comparison was drawn with behavioral and structural changes recorded in the control group. The results showed that methadone administration interrupted spatial learning and memory function. Accordingly, treating rats with methadone not only induced cell death but also prompted the actuation of microgliosis, astrogliosis, and apoptotic biomarkers. Furthermore, the results demonstrated that treating rats with methadone decreased the complexity of astrocyte processes and the complexity of microglia processes. These findings suggest that methadone altered the special distribution of neurons. Also, a substantial increase was observed in the expression of TNF-α due to methadone. According to the findings, methadone administration exerts a neurodegenerative effect on the hippocampus via dysregulation of microgliosis, astrogliosis, apoptosis, and neuro-inflammation.

Difference in topological organization of white matter structural connectome between methamphetamine and heroin use disorder

The psychological symptoms caused by heroin and methamphetamine are significantly different in people with substance use disorders. The topological organization of structural connections that may underlie these differences remains unknown. The study sample consisted of 23 males with methamphetamine use disorder (MAUD), 20 males with heroin use disorder (HUD), and 21 male healthy controls (HCs) who were demographically matched. Diffusion tensor imaging and probabilistic tractography were used for white matter network construction. Psychological symptoms were evaluated by the Symptom Checklist-90. Using graph theoretical analysis, we examined the difference in graph-level and nodal-level properties among the groups. The network Hubs distribution and the relationship between the network alterations and psychological symptoms were identified. The MAUD group demonstrated significantly higher scores on anxiety, hostility, and symptoms of schizophrenia than the HUD and HCs groups. The HUD group showed significantly higher global efficiency and network strength than the HCs group, and higher network strength than the MAUD group. Compared with the HUD group, the MAUD group showed significantly lower Nodal Strength and efficiency, distributed mainly in the temporal, parietal, and occipital regions. We also found the network Hubs were decreased in the MAUD group, but increased in the HUD group. The Nodal Strength in the right superior temporal gyrus was significantly correlated with psychological symptoms in the MAUD group. These findings reflect the significant differences in topological structural connection between HUD and MAUD. This evidence helps shed some light on the neurobiological mechanisms of the psychological differences between HUD and MAUD, and extend our understanding of the structural disruption underlying MAUD-related psychological symptoms.

MR spectroscopy and diffusion imaging in people with human immunodeficiency virus: Relationships to clinical and immunologic findings

BACKGROUND AND PURPOSE

People with human immunodeficiency virus (HIV; PWH) present a complex array of immunologic and medical disorders that impact brain structure and metabolism, complicating the interpretation of neuroimaging. This pilot study of well-characterized multi-morbid PWH examined how medical and immunologic factors predicted brain characteristics on proton MR spectroscopy (1H-MRS) and diffusion-weighted imaging (DWI).

METHODS

Eighteen individuals on combination antiretroviral therapy (cART), with mean age of 56 years, underwent medical history review, neuroimaging, and on the day of imaging, blood draw for assay of 20 plasma cytokines and flow cytometric characterization of peripheral blood mononuclear cell subsets. Predictors of n-acetyl aspartate, choline, myoinositol, glutamate/glutamine, fractional anisotropy and mean diffusivity were identified through bivariate correlation; those significant at p < .1000 were advanced to multivariate analysis, with models created for each neuroimaging outcome.

RESULTS

Monocyte subsets and diverse cytokines accounted for 16 of 25 (64%) variables predicting 1H-MRS spectra in frontal gray and white matter and basal ganglia; monocyte subsets did not predict any DWI characteristic. In contrast, age, presence of hypertension, and duration of HIV infection accounted for 13 of 25 (52%) variables predicting diffusion characteristics in the corpus callosum, thalamic radiations, and basal ganglia but only 3 of 25 (12%) predictors of 1H-MRS features.

CONCLUSIONS

1H-MRS neurometabolites were most often predicted by immunologic factors sensitive to temporal variation, whereas DWI metrics were more often related to longer-term disease state. In multi-morbid cART-era populations, selection and interpretation of neuroimaging modalities should account for complex temporal and pathogenetic influences of immunologic abnormality, disease state, and aging.

Enriched Environment Ameliorates Cognitive Deficits and Locomotor Sensitization in Morphine-Withdrawn Rats Receiving Methadone Maintenance Treatment

OBJECTIVE

This study was designed to examine whether enriched environments (EE) would attenuate object recognition and spatial learning and memory deficits and locomotor sensitization induced by methadone maintenance treatment (MMT) in morphine-withdrawn rats.

METHODS

Male Wistar rats (170 ± 10 g) were injected with bi-daily doses (10 mg/kg, 12-h intervals) of morphine for 14 days. Rats receiving MMT were reared in the standard environment (SE) or EE during 30 days of morphine withdrawal. Then, the rats were tested for object recognition (the object recognition memory test, ORMT) and spatial learning and memory (the water maze) and then challenged with morphine (1 mg/kg, i.p.) and evaluated for locomotor activity (open-field box).

RESULTS

The results revealed that the dependent/saline/EE (D/Sal/EE) and D/methadone/EE (D/Meth/EE) rats exhibited significant preference for the new object (p = 0.006 and p = 0.049), spent more time in the target zone (p = 0.045 and p = 0.005) on the water maze, and displayed a lower level of distance traveled (p = 0.002 and p = 0.0001) compared to their control groups reared in SE.

CONCLUSIONS

We conclude that exposure to EE could ameliorate the object recognition and spatial memory deficits and also decrease locomotor sensitivity in morphine-withdrawn rats receiving MMT. Thus, EE may be beneficial in the treatment of addiction during MMT.

Increased Pain Symptomatology Among Females vs. Males With Fragile X-Associated Tremor/Ataxia Syndrome

Individuals with the fragile X premutation report symptoms of chronic pain from multiple systems, have increased incidence of comorbid conditions where pain is a prominent feature, and pathophysiology that supports disrupted pain regulation, inflammation, and energy imbalance. Less is known about how pain manifests for the subpopulation of carriers that develop the motor and cognitive changes of fragile X-associated tremor and ataxia syndrome (FXTAS), and how pain may differ between men and women. We gathered data collected from 104 males and females with FXTAS related to chronic pain, comorbid conditions related to pain, and medications used for pain control to further explore the types of pain experienced and to better characterize how individuals with the fragile X premutation experience pain sensation across genders. We found that women experience significantly more pain symptoms than men, particularly allodynia (20 vs. 2.0%, p = 0.008), peripheral neuropathy pain (43.9 vs. 25.4%, p = 0.0488), migraine (43.9 vs. 14.5%, p = 0.0008), fibromyalgia (26.8 vs. 0%, p = 0.0071) and back pain (48.5 vs. 23.4%, p = 0.008). We found onset of peripheral neuropathy predicts the onset of ataxia (β = 0.63 ± 0.25, p = 0.019) and tremor (β = 0.56 ± 0.17, p = 0.004) across gender. Women also report significantly more anxiety (82.9 vs. 39.7%, p < 0.001), which has implications for ideal pain treatment. These pain symptoms need to be recognized in the medical history and treated appropriately, with consideration for overlapping comorbidities.

Increased Amplitude of Low-Frequency Fluctuation in Right Angular Gyrus and Left Superior Occipital Gyrus Negatively Correlated With Heroin Use

Abnormal amplitude of low-frequency fluctuation has been implicated in heroin addiction. However, previous studies lacked consistency and didn't consider the impact of confounding factors such as methadone and alcohol. Fifty-one heroin-dependent (HD) individuals and 40 healthy controls underwent resting-state functional magnetic resonance imaging. The 'amplitude of low-frequency fluctuation' (ALFF) value was calculated and support vector machine (SVM) classification analysis was applied to analyze the data. Compared with healthy controls, heroin addicts exhibited increased ALFF in the right angular gyrus (AG) and left superior occipital gyrus (SOG). A negative correlation was observed between increased ALFF in the right angular gyrus and left superior occipital gyrus and the duration of heroin use (p 1=0.004, r 1=-0.426; p 2=0.009, r 2=-0.361). Moreover, the ALFF in the right AG and left SOG could discriminate the HD subjects from the controls with acceptable accuracy (Acc1=64.85%, p 1=0.004; Acc2=63.80%, p 2=0.005). HD patients showed abnormal ALFF in the brain areas involved in semantic memory and visual networks. The longer HD individuals abused heroin, the less the ALFF of associated brain regions increased. These observed patterns suggested that the accumulative effect of heroin's neurotoxicity overpowered self-recovery of the brain and may be applied as a potential biomarker to identify HD individuals from the controls.

Cognitive profiles in persons with opioid use disorder enrolled in methadone treatment

Cognitive impairment is common in persons with opioid use disorder and associated with poor treatment outcomes, including elevated risk for relapse. Much less is known about the underlying structure of these deficits and the possible presence of cognitive phenotypes. A total of 177 adults (average 42.2 years of age, 52.0% male, 65.5% Caucasian) enrolled in a methadone maintenance treatment program completed the NIH Toolbox as part of a larger project. Cluster analyses revealed a 2-cluster solution-persons with intact cognitive function in all domains (n = 93; Intact) and those with impairments on tests of attention and executive function (n = 83; Impaired). Follow-up analyses revealed that the Impaired group was slightly older, more likely to self-identify as a racial/ethnic minority, and less likely to report consuming alcohol four or more times per week. These findings suggest the existence of distinct cognitive profiles in persons with opioid use disorder and encourage further examination, particularly studies to examine the possible benefits of routine screening for cognitive impairment as part of substance use treatment.

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.

Fragile X-Associated Neuropsychiatric Disorders (FXAND)

Fragile X syndrome (FXS) is caused by the full mutation (>200 CGG repeats) in the Fragile X Mental Retardation 1 (FMR1) gene. It is the most common inherited cause of intellectual disability (ID) and autism. This review focuses on neuropsychiatric disorders frequently experienced by premutation carriers with 55 to 200 CGG repeats and the pathophysiology involves elevated FMR1 mRNA levels, which is different from the absence or deficiency of fragile X mental retardation protein (FMRP) seen in FXS. Neuropsychiatric disorders are the most common problems associated with the premutation, and they affect approximately 50% of individuals with 55 to 200 CGG repeats in the FMR1 gene. Neuropsychiatric disorders in children with the premutation include anxiety, ADHD, social deficits, or autism spectrum disorders (ASD). In adults with the premutation, anxiety and depression are the most common problems, although obsessive compulsive disorder, ADHD, and substance abuse are also common. These problems are often exacerbated by chronic fatigue, chronic pain, fibromyalgia, autoimmune disorders and sleep problems, which are also associated with the premutation. Here we review the clinical studies, neuropathology and molecular underpinnings of RNA toxicity associated with the premutation. We also propose the name Fragile X-associated Neuropsychiatric Disorders (FXAND) in an effort to promote research and the use of fragile X DNA testing to enhance recognition and treatment for these disorders.

Delay-Dependent Impairments in Memory and Motor Functions After Acute Methadone Overdose in Rats

Methadone is used as a substitution drug for the treatment of opioid dependence and chronic pain. Despite its widespread use and availability, there is a serious concern with respect to the relative safety of methadone. The purpose of this study was to characterize how acute methadone overdose affects the cognitive and motor performance of naïve healthy rats. The methadone overdose was induced by administering an acute toxic dose of methadone (15 mg/kg; ip; the equivalent dose of 80% of LD50) to adolescent rats. Resuscitation using a ventilator pump along with a single dose of naloxone (2 mg/kg; ip) was administered following the occurrence of apnea. The animals which were successfully resuscitated divided randomly into three apnea groups that evaluated either on day 1, 5, or 10 post-resuscitation (M/N-Day 1, M/N-Day 5, and M/N-Day 10 groups) in the Y-maze and novel object memory recognition tasks as well as pole and rotarod tests. The data revealed that a single toxic dose of methadone had an adverse effect on spontaneous behavior. In addition, Recognition memory impairment was observed in the M/N-Day 1, 5, and 10 groups after methadone-induced apnea. Further, descending time in the M/N-Day 5 group increased significantly in comparison with its respective Saline control group. The overall results indicate that acute methadone-overdose-induced apnea produced delay-dependent cognitive and motor impairment. We suggest that methadone poisoning should be considered as a possible cause of delayed neurological disorders, which might be transient, in some types of memory or motor performance in naïve healthy rats.

Longitudinal behavioral and fMRI-based assessment of inhibitory control in heroin addicts on methadone maintenance treatment

The objective of the present study was to determine whether methadone maintenance treatment (MMT) in heroin-dependent patients affects inhibitory control, whether any MMT-induced changes correlate with methadone dose and MMT duration, and whether these changes depend on the psychological characteristics of patients, such as depression, anxiety and impulsivity. Response inhibition in the GO/NO-GO test was combined with functional magnetic resonance imaging (fMRI) scanning data to examine whether MMT affects inhibitory control in 21 heroin-addicted patients who had already undergone at least three months of MMT. Patients were evaluated one year prior to and after the MMT period. Participants exhibited no difference in their GO/NO-GO reaction time and accuracy rate, or in their false alarm rate under NO-GO conditions. However, increased activation was detected in numerous brain regions in their 12-month fMRI scans, although these were not in the frontal-striatal loop. Increased fMRI activation in the left precentral gyrus and superior temporal gyrus were negatively correlated with the daily methadone dose and total methadone dose during the one-year study period. In conclusion, these results suggested that MMT over one year does not significantly change the behavioral indicators of inhibitory control function in heroin-dependent patients. The increase in activation leads to the hypothesis that MMT over one year may increase cognitive inhibitory control, which may be the result of the combined negative effect of methadone and the positive effect of functional recovery after withdrawal of heroin.

Treadmill exercise attenuates the severity of physical dependence, anxiety, depressive-like behavior and voluntary morphine consumption in morphine withdrawn rats receiving methadone maintenance treatment

This study was designed to examine whether treadmill exercise would attenuate the severity of physical dependence, methadone-induced anxiety, depression and voluntary morphine consumption in morphine withdrawn rats receiving methadone maintenance treatment (MMT). The rats were chronically treated with bi-daily doses (10 mg/kg, at 12 h intervals) of morphine for 14 days. The exercising rats receiving MMT were forced to run on a motorized treadmill for 30 days during morphine withdrawal. Then, rats were tested for the severity of morphine dependence, the elevated plus-maze (EPM), sucrose preference test (SPT) and voluntary morphine consumption using a two-bottle choice (TBC) paradigm. The results showed that naloxone- precipitated opioid withdrawal signs were decreased in exercising morphine-dependent rats receiving MMT than sedentary rats. Also, the exercising morphine-dependent rats receiving MMT exhibited an increased time on open arms, preference for sucrose and a lower morphine preference ratio than sedentary rats. We conclude that treadmill exercise decreased the severity of physical dependence, anxiety/depressive-like behaviors and also the voluntary morphine consumption in morphine withdrawn rats receiving MMT. Thus, exercise may benefit in the treatment of addicts during MMT.

A possible biomarker for methadone related deaths

Methadone (MTH) concentrations in those dying of MTH toxicity totally overlap concentrations where the presence of MTH is only an incidental finding, making it very difficult to make distinctions in actual cases. A biomarker, be it anatomical or biochemical for MTH toxicity is badly needed, particularly if that markers were known to disrupt effective ventilation. Because the brainstem houses the regulatory centers for cardiorespiratory-control enters, it would seem to be the most likely anatomical site to seek abnormalities in cardiorespiratory control.

OBJECTIVE

To locate and describe the cells of nucleus of the solitary tract (TS)(NTS) in human brainstem and determine if neuronal cell death, either necrotic or apoptotic, within the TS of humans is more common in deaths due directly to MTH toxicity than with in the solitary tract itself.

DESIGN, SETTING, PARTICIPANTS

This was a single cohort study of MTH related decedents autopsied at a large university hospital. Each decedent had a recent history of non medical/illicit MTH use and had been pronounced dead in the field, prior to ever reaching the hospital. Complete autopsy and complete toxicology testing were performed on the formalin fixed brains of each individual. Multiple blocks were prepared of the area of interest, namely the tissue lying immediately between the inferior and the super colliculi. This volume, by definition, would have included the area of the Rostral Ventrolateral Medulla (RVLM), the location of the TS. Immunohistochemistry studies utilizing caspase-9 reaction (a protease enzyme involved in the process of preprogrammed death) were performed in order to estimate the degree and proportion of neuronal apoptosis, and also access the degree of classical necrosis within the NTS.

MAIN OUTCOMES AND MEASURES

The primary outcome measure was the presence or absence of neuronal apoptosis and/or necrosis within the NTS.

RESULTS

Cells displaying evidence of early apoptosis and advanced apoptosis, consisting primarily of nuclear fragmentation, admixed with other neurons displaying the features of classic necrosis were found. Evidence of classic necrosis was identifiable in most of the controls, though minor degrees of apoptosis were identifiable with Caspase staining and quantitative image analysis of immunohistochemical stains.

CONCLUSIONS

and Relevance: Our study shows that neurons, primarily along the TS, but occasionally in other cell nuclei (even controls) are vulnerable, both to direct MTH toxicity (via apoptosis) and indirectly (via hypoxia leading to classical cell necrosis). When MTH is found to be present in significant concentrations, but apoptotic lesions are absent, it would be reasonable to assume that MTH was not primarily the cause of cardiorespiratory arrest.

Opiate Drugs with Abuse Liability Hijack the Endogenous Opioid System to Disrupt Neuronal and Glial Maturation in the Central Nervous System

The endogenous opioid system, comprised of multiple opioid neuropeptide and receptor gene families, is highly expressed by developing neural cells and can significantly influence neuronal and glial maturation. In many central nervous system (CNS) regions, the expression of opioid peptides and receptors occurs only transiently during development, effectively disappearing with subsequent maturation only to reemerge under pathologic conditions, such as with inflammation or injury. Opiate drugs with abuse liability act to modify growth and development by mimicking the actions of endogenous opioids. Although typically mediated by μ-opioid receptors, opiate drugs can also act through δ- and κ-opioid receptors to modulate growth in a cell-type, region-specific, and developmentally regulated manner. Opioids act as biological response modifiers and their actions are highly contextual, plastic, modifiable, and influenced by other physiological processes or pathophysiological conditions, such as neuro-acquired immunodeficiency syndrome. To date, most studies have considered the acute effects of opiates on cellular maturation. For example, activating opioid receptors typically results in acute growth inhibition in both neurons and glia. However, with sustained opioid exposure, compensatory factors become operative, a concept that has been largely overlooked during CNS maturation. Accordingly, this article surveys prior studies on the effects of opiates on CNS maturation, and also suggests new directions for future research in this area. Identifying the cellular and molecular mechanisms underlying the adaptive responses to chronic opiate exposure (e.g., tolerance) during maturation is crucial toward understanding the consequences of perinatal opiate exposure on the CNS.

Resting-state Abnormalities in Heroin-dependent Individuals

Drug addiction is a major health problem worldwide. Recent neuroimaging studies have shed light into the underlying mechanisms of drug addiction as well as its consequences to the human brain. The most vulnerable, to heroin addiction, brain regions have been reported to be specific prefrontal, parietal, occipital, and temporal regions, as well as, some subcortical regions. The brain regions involved are usually linked with reward, motivation/drive, memory/learning, inhibition as well as emotional control and seem to form circuits that interact with each other. So, along with neuroimaging studies, recent advances in resting-state dynamics might allow further assessments upon the multilayer complexity of addiction. In the current manuscript, we comprehensively review and discuss existing resting-state neuroimaging findings classified into three overlapping and interconnected groups: functional connectivity alterations, structural deficits and abnormal topological properties. Moreover, behavioral traits of heroin-addicted individuals as well as the limitations of the currently available studies are also reviewed. Finally, in need of a contemporary therapy a multimodal therapeutic approach is suggested using classical treatment practices along with current neurotechonologies, such as neurofeedback and goal-oriented video-games.

Cerebellar microstructural abnormalities in bipolar depression and unipolar depression: A diffusion kurtosis and perfusion imaging study

BACKGROUND

Depression in the context of bipolar disorder (BD) is often misdiagnosed as unipolar depression (UD), leading to mistreatment and poor clinical outcomes. However, little is known about the similarities and differences in cerebellum between BD and UD.

METHODS

Patients with BD (n=35) and UD (n=30) during a depressive episode as well as 40 healthy controls underwent diffusional kurtosis imaging (DKI) and three dimensional arterial spin labeling (3D ASL). The DKI parameters including mean kurtosis (MK), axial kurtosis (Ka), radial kurtosis (Kr),fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (Da) and radial diffusivity (Dr) and 3D ASL parameters (i.e. cerebral blood flow) was measured by using regions-of-interest (ROIs) analysis in the superior cerebellar peduncles (SCP), middle cerebellar peduncles (MCP) and dentate nuclei (DN) of cerebellum.

RESULTS

Patients with UD exhibited significant differences from controls for DKI measures in bilateral SCP and MCP and cerebral blood flow (CBF) in bilateral SCP and left DN. Patients with BD exhibited significant differences from controls for DKI measures in the right MCP and left DN and CBF in the left DN. Patients with UD showed significantly lower MD values compared with patients with BD in the right SCP. Correlation analysis showed there were negative correlations between illness duration and MD and Dr values in the right SCP in UD.

LIMITATIONS

This study was cross-sectional and the sample size was not large. Parts of the patients included were under medication prior to MRI scanning.

CONCLUSIONS

Our findings provide new evidence of microstructural changes in cerebellum in BD and UD. The two disorders may have overlaps in microstructural abnormality in MCP and DN during the depressive period. Microstructural abnormality in SCP may be a key neurobiological feature of UD.

The White Matter Microintegrity Alterations of Neocortical and Limbic Association Fibers in Major Depressive Disorder and Panic Disorder: The Comparison

The studies regarding to the comparisons between major depressive disorder (MDD) and panic disorder (PD) in the microintegrity of white matter (WM) are uncommon. Therefore, we tried to a way to classify the MDD and PD. Fifty-three patients with 1st-episode medication-naive PD, 54 healthy controls, and 53 patients with 1st-episode medication-naive MDD were enrolled in this study. The controls and patients were matched for age, gender, education, and handedness. The diffusion tensor imaging scanning was also performed. The WM microintegrity was analyzed and compared between 3 groups of participants (ANOVA analysis) with age and gender as covariates. The MDD group had lower WM microintegrity than the PD group in the left anterior thalamic radiation, left uncinate fasciculus, left inferior fronto-occipital fasciculus, and bilateral corpus callosum. The MDD group had reductions in the microintegrity when compared to controls in the bilateral superior longitudinal fasciculi, inferior longitudinal fasciculi, inferior fronto-occipital fasciculi, and corpus callosum. The PD group had lower microintegrity in bilateral superior longitudinal fasciculi and left inferior fronto-occipital fasciculus when compared to controls. The widespread pattern of microintegrity alterations in fronto-limbic WM circuit for MDD was different from restrictive pattern of alterations for PD.

Brain white matter integrity in heroin addicts during methadone maintenance treatment is related to relapse propensity

INTRODUCTION

Cognitive deficits caused by heroin-induced white matter (WM) impairments hinder addicts' engagement in and benefit from treatment. The predictive value of WM integrity in heroin addicts during methadone maintenance treatment (MMT) for future relapse is unclear.

METHODS

Forty-eight MMT patients were given baseline diffusion tensor imaging scans and divided into heroin relapsers (HR, 25 cases) and abstainers (HA, 23 cases) according to the results of 6-month follow-up. Intergroup comparisons were performed for fractional anisotropy (FA), radial diffusivity (RD), and axial diffusivity (AD). The correlation between diffusion tensor imaging indices and the degree of heroin relapse was analyzed.

RESULTS

Compared with HA group, HR group had reduced FA in the right retrolenticular part, left anterior and posterior limb of internal capsule, bilateral anterior corona radiata, and right external capsule. Three out of the six regions showed increased RD, with no changes in AD. The FA and AD values in the left posterior limb of internal capsule correlated negatively with the heroin-positive urinalysis rate within follow-up.

CONCLUSIONS

Lower WM integrity in MMT patients may add to neurobiological factors associated with relapse to heroin use. Strategies for improving WM integrity provide a new perspective to prevent future relapse to heroin abuse.

Methadone use in a male with the FMRI premutation and FXTAS

The fragile X-associated tremor ataxia syndrome (FXTAS) is caused by the premutation in FMR1 gene. Recent reports of environmental toxins appear to worsen the progression of FXTAS. Here we present a case of male adult with FXTAS and a long history of methadone use. The patient shows a faster progression in both symptoms of disease and MRI changes compared to what is typically seen in FXTAS. There has been no research regarding the role of narcotics in onset, progression, and severity of FXTAS symptoms. However, research has shown that narcotics can have a negative impact on several neurodegenerative diseases, and we hypothesize that in this particular case, methadone may have contributed to a faster progression of FXTAS as well as exacerbating white matter disease through RNA toxicity seen in premutation carriers.

Diffusivity of the uncinate fasciculus in heroin users relates to their levels of anxiety

Heroin use is closely associated with emotional dysregulation, which may explain its high comorbidity with disorders such as anxiety and depression. However, the understanding of the neurobiological etiology of the association between heroin use and emotional dysregulation is limited. Previous studies have suggested an impact of heroin on diffusivity in white matter involving the emotional regulatory system, but the specificity of this finding remains to be determined. Therefore, this study investigated the association between heroin use and diffusivity of white matter tracts in heroin users and examined whether the tracts were associated with their elevated anxiety and depression levels. A sample of 26 right-handed male abstinent heroin users (25 to 42 years of age) and 32 matched healthy controls (19 to 55 years of age) was recruited for this study. Diffusion tensor imaging data were collected, and their levels of anxiety and depression were assessed using the Hospital Anxiety and Depression Scale. Our findings indicated that heroin users exhibited higher levels of anxiety and depression, but the heroin use-associated left uncinate fasciculus was only related to their anxiety level, suggesting that association between heroin and anxiety has an incremental organic basis but that for depression could be a threshold issue. This finding improves our understanding of heroin addiction and its comorbid affective disorder and facilitates future therapeutic development.

White matter damage and systemic inflammation in obstructive sleep apnea

STUDY OBJECTIVES

To evaluate white matter integrity in patients with obstructive sleep apnea (OSA) using diffusion tensor imaging (DTI) and to assess its relationship with systemic inflammation.

DESIGN

Cross-sectional study.

SETTING

One tertiary medical center research institute.

PATIENTS OR PARTICIPANTS

Twenty patients with severe OSA (apnea-hypopnea index [AHI] > 30, 18 men and 2 women) and 14 healthy volunteers (AHI < 5, 11 men and 3 women).

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

Patients with severe OSA and healthy volunteers underwent polysomnography to determine the severity of sleep apnea, and DTI scanning to determine fiber integrity. Early or late phase changes in leukocyte apoptosis and its subsets were determined by flow cytometry. DTI-related indices (including fractional anisotropy [FA], axial diffusivity [AD], radial diffusivity [RD], and mean diffusivity [MD]) were derived from DTI. The FA maps were compared using voxel-based statistics to determine differences between the severe OSA and control groups. The differences in DTI indices, clinical severity, and leukocyte apoptosis were correlated after adjusting for age, sex, body mass index, and systolic blood pressure. Exploratory group-wise comparison between the two groups revealed that patients with OSA exhibited low FA accomplished by high RD in several brain locations, without any differences in AD and MD. The FA values were negatively correlated with clinical disease severity and leukocyte early apoptosis.

CONCLUSIONS

Obstructive sleep apnea impairs white matter integrity in vulnerable regions, and this impairment is associated with increased disease severity. The possible interactions between systemic inflammation and central nervous system microstructural damage may represent variant hypoxic patterns and their consequent processes in OSA.

Assessment of whole brain white matter integrity in youths and young adults with a family history of substance-use disorders

Individuals with a family history of substance use disorders (FH+) are at a greater risk of developing substance use disorders than their peers with no such family histories (FH-) and this vulnerability is proportional to the number of affected relatives (FH density). The risk for developing substance use disorders peaks during adolescence to early adulthood in the general population, and that is thought to be related to delayed maturation of frontocortical and frontostriatal functional circuits. We hypothesized that FH+ youth and young adults have impaired myelination of frontocortical and frontostriatal white matter tracts. We examined fractional anisotropy (FA) data in 80 FH+ and 34 FH- youths (12.9 ± 1.0 years) and in 25 FH+ and 30 FH- young adults (24.3 ± 3.4 years). FH+ youths had lower FA values in both frontocortical and frontostriatal tracts as well as parietocortical tracts including the anterior, superior and posterior corona radiata and the superior frontal-occipital fasciculus. Moreover, FA values in these tracts were negatively correlated with FH density. FH+ adults had lower FA values in two frontocortical tracts: the genu of the corpus callosum and anterior corona radiata and also significant negative correlations between FA and FH density in these same tracts. In both groups, lower FA values corresponded to higher radial diffusivity suggesting reduced axonal myelination. We interpreted our findings as evidence for impaired myelination of frontal white matter that was proportional to FH density. Our data suggest that deficits may partially resolve with age, paralleling an age-related decline in risk for developing substance use disorders.

Assessment of whole brain white matter integrity in youths and young adults with a family history of substance-use disorders

Individuals with a family history of substance use disorders (FH+) are at a greater risk of developing substance use disorders than their peers with no such family histories (FH-) and this vulnerability is proportional to the number of affected relatives (FH density). The risk for developing substance use disorders peaks during adolescence to early adulthood in the general population, and that is thought to be related to delayed maturation of frontocortical and frontostriatal functional circuits. We hypothesized that FH+ youth and young adults have impaired myelination of frontocortical and frontostriatal white matter tracts. We examined fractional anisotropy (FA) data in 80 FH+ and 34 FH- youths (12.9 ± 1.0 years) and in 25 FH+ and 30 FH- young adults (24.3 ± 3.4 years). FH+ youths had lower FA values in both frontocortical and frontostriatal tracts as well as parietocortical tracts including the anterior, superior and posterior corona radiata and the superior frontal-occipital fasciculus. Moreover, FA values in these tracts were negatively correlated with FH density. FH+ adults had lower FA values in two frontocortical tracts: the genu of the corpus callosum and anterior corona radiata and also significant negative correlations between FA and FH density in these same tracts. In both groups, lower FA values corresponded to higher radial diffusivity suggesting reduced axonal myelination. We interpreted our findings as evidence for impaired myelination of frontal white matter that was proportional to FH density. Our data suggest that deficits may partially resolve with age, paralleling an age-related decline in risk for developing substance use disorders.

Diffusion tensor imaging study of white matter damage in chronic meningitis

Tuberculous meningitis (TBM) and cryptococcal meningitis (CM) are two of the most common types of chronic meningitis. This study aimed to assess whether chronic neuro-psychological sequelae are associated with micro-structure white matter (WM) damage in HIV-negative chronic meningitis. Nineteen HIV-negative TBM patients, 13 HIV-negative CM patients, and 32 sex- and age-matched healthy volunteers were evaluated and compared. The clinical relevance of WM integrity was studied using voxel-based diffusion tensor imaging (DTI) magnetic resonance imaging. All of the participants underwent complete medical and neurologic examinations, and neuro-psychological testing. Differences in DTI indices correlated with the presence of neuro-psychological rating scores and cerebrospinal fluid (CSF) analysis during the initial hospitalization. Patients with CM had more severe cognitive deficits than healthy subjects, especially in TBM. There were changes in WM integrity in several limbic regions, including the para-hippocampal gyrus and cingulate gyrus, and in the WM close to the globus pallidus. A decline in WM integrity close to the globus pallidus and anterior cingulate gyrus was associated with worse CSF analysis profiles. Poorer DTI parameters directly correlated with worse cognitive performance on follow-up. These correlations suggest that WM alterations may be involved in the psychopathology and pathophysiology of co-morbidities. Abnormalities in the limbic system and globus pallidus, with their close relationship to the CSF space, may be specific biomarkers for disease evaluation.

Cognitive control in opioid dependence and methadone maintenance treatment

BACKGROUND

Substance misuse is associated with cognitive dysfunction. We used a stop signal task to examine deficits in cognitive control in individuals with opioid dependence (OD). We examined how response inhibition and post-error slowing are compromised and whether methadone maintenance treatment (MMT), abstinence duration, and psychiatric comorbidity are related to these measures in individuals with OD.

METHODS

Two-hundred-and-sixty-four men with OD who were incarcerated at a detention center and abstinent for up to 2 months (n = 108) or at a correctional facility and abstinent for approximately 6 months (n = 156), 65 OD men under MMT at a psychiatric clinic, and 64 age and education matched healthy control (HC) participants were assessed. We computed the stop signal reaction time (SSRT) to index the capacity of response inhibition and post-error slowing (PES) to represent error-related behavioral adjustment, as in our previous work. We examined group effects with analyses of variance and covariance analyses, followed by planned comparisons. Specifically, we compared OD and HC participants to examine the effects of opioid dependence and MMT and compared OD sub-groups to examine the effects of abstinence duration and psychiatric comorbidity.

RESULTS

The SSRT was significantly prolonged in OD but not MMT individuals, as compared to HC. The extent of post-error slowing diminished in OD and MMT, as compared to HC (trend; p = 0.061), and there was no difference between the OD and MMT groups. Individuals in longer abstinence were no less impaired in these measures. Furthermore, these results remained when psychiatric comorbidities including misuse of other substances were accounted for.

CONCLUSIONS

Methadone treatment appears to be associated with relatively intact cognitive control in opioid dependent individuals. MMT may facilitate public health by augmenting cognitive control and thereby mitigating risky behaviors in heroin addicts.

White matter impairment in chronic heroin dependence: a quantitative DTI study

Exposure to addictive drugs has been associated with disrupted brain white matter integrity. A few studies have examined the white matter deficits in heroin users; however, the results were influenced by the use of substitution drugs such as methadone and buprenorphine. The present study assessed the alteration in white matter integrity and heroin-related neuropathology in heroin dependents who had not received any replacement therapy using quantitative diffusion tensor imaging (DTI). The study comprised 17 heroin-dependent (HD) subjects and 15 matched healthy controls (HC). Fractional anisotropy (FA) and eigenvalues (λ┴, λ||) of white matter in the whole brain were measured and compared using a voxel-based analysis. The correlation between DTI measurements in identified regions and history of heroin exposure was tested by partial correlation analysis. Compared with HCs, HD subjects displayed decreased FA in the bilateral frontal lobe sub-gyrus, cingulate gyrus, medial frontal gyrus, extra-nuclear, left temporal lobe sub-gyrus and right superior frontal gyrus. Among these regions, the HD group had significantly increased λ┴ in the bilateral frontal lobe sub-gyrus, cingulate gyrus and extra-nuclear relative to the HC group. There were no group differences in λ||. In addition, there were no significant correlations between duration of heroin use or accumulated dosage and FA or λ┴ values. In conclusion, chronic heroin-dependent subjects had widespread disruption of white matter structural connectivity located mainly in anterior and superior regions of the brain. Damage to myelin other than axons was the primary pathological feature in the brain of the heroin user.