Impulsivity is Associated with Increased Metabolism in the Fronto-Insular Network in Parkinson’s Disease

Front. Behav. Neurosci. 9:317. doi: 10.3389/fnbeh.2015.00317 Various neuroimaging studies demonstrated that the fronto-insular network is implicated in impulsive behavior. We compared glucose metabolism (as a proxy measure of neural activity) among 24 patients with Parkinson’s disease (PD) who presented with low or high levels of impulsivity based on the Barratt Impulsiveness Scale 11 (BIS) scores. Subjects underwent 18-fluorodeoxyglucose positron emission tomography (FDG-PET) and the voxel-wise group difference of FDG-metabolism was analyzed in Statistical Parametric Mapping (SPM8). Subsequently, we performed a partial correlation analysis between the FDG-metabolism and BIS scores, controlling for covariates (i.e., age, sex, severity of disease and levodopa equivalent daily doses). Voxel-wise group comparison revealed higher FDG-metabolism in the orbitofrontal cortex (OFC), anterior cingulate cortex (ACC), and right insula in patients with higher impulsivity scores. Moreover, there was a positive correlation between the FDG-metabolism and BIS scores. Our findings provide evidence that high impulsivity is associated with increased FDG-metabolis

Sleep Disorders in Methadone Maintenance Treatment Volunteers and Opium-‎dependent Patients

Background‎: The relationship between substance use and sleep is bidirectional. Substance use directly causes sleep disturbances, and sleep problems are a critical factor in substance-use relapse. Methods: This study evaluated sleep disorders in 65 methadone maintenance treatment (MMT) patients, and 61 opium-dependent patients who did not receive any treatment between September 2011 and July 2012 in Kermanshah, Iran. Both groups filled out the Pittsburgh Sleep Quality Index (PSQI) and Global Sleep Assessment Questionnaire (GSAQ).Findings: Sleep disorders were remarkably similar in both groups: 78.5% of MMT patients and 87.7% of opium-dependent patients suffered from sleep problems. Sleep disorders in the opium-dependent group were remarkably higher and more prominent.Conclusion: Compared to opium, MMT does not have as many negative effects on sleep and is more effective in mitigating sleep problems

Insular dysfunction within the salience network is associated with severity of symptoms and aberrant inter-network connectivity in major depressive disorder

Major depressive disorder (MDD) is characterized by altered intrinsic functional connectivity within (intra-iFC) intrinsic connectivity networks (ICNs),such as the Default Mode- (DMN),Salience- (SN) and Central Executive Network (CEN). It has been proposed that aberrant switching between DMN-mediated self-referential and CEN-mediated goal-directed cognitive processes might contribute to MDD, possibly explaining patients' difficulties to disengage the processing of self-focused, often negatively biased thoughts. Recently, it has been shown that the right anterior insula (rAl) within the SN is modulating DMN/CEN interactions. Since structural and functional alterations within the Al have been frequently reported in MDD, we hypothesized that aberrant intra-iFC in the SN's rAl is associated with both aberrant iFC between DMN and CEN (inter-iFC) and severity of symptoms in MDD. Twenty-five patients with MDD and 25 healthy controls were assessed using resting-state fMRI (rs-fMRI) and psychometric examination. High-model-order independent component analysis (ICA) of rs-fMRI data was performed to identify ICNs including DMN, SN, and CEN. Intra-iFC within and inter-iFC between distinct subsystems of the DMN, SN, and CEN were calculated, compared between groups and correlated with the severity of symptoms. Patients with MDD showed (1) decreased intra-iFC within the SN's rAl,(2) decreased inter-iFC between the DMN and CEN, and (3) increased inter-iFC between the SN and DMN. Moreover, decreased intra-iFC in the SN's rAl was associated with severity of symptoms and aberrant DMN/CEN interactions, with the latter losing significance after correction for multiple comparisons. Our results provide evidence for a relationship between aberrant intra-iFC in the salience network's rAl, aberrant DMN/CEN interactions and severity of symptoms, suggesting a link between aberrant salience mapping, abnormal coordination of DMN/CEN based cognitive processes and psychopathology in MDD

ENIGMA-Sleep:Challenges, opportunities, and the road map

Neuroimaging and genetics studies have advanced our understanding of the neurobiology of sleep and its disorders. However, individual studies usually have limitations to identifying consistent and reproducible effects, including modest sample sizes, heterogeneous clinical characteristics and varied methodologies. These issues call for a large-scale multi-centre effort in sleep research, in order to increase the number of samples, and harmonize the methods of data collection, preprocessing and analysis using pre-registered well-established protocols. The Enhancing NeuroImaging Genetics through Meta-Analysis (ENIGMA) consortium provides a powerful collaborative framework for combining datasets across individual sites. Recently, we have launched the ENIGMA-Sleep working group with the collaboration of several institutes from 15 countries to perform large-scale worldwide neuroimaging and genetics studies for better understanding the neurobiology of impaired sleep quality in population-based healthy individuals, the neural consequences of sleep deprivation, pathophysiology of sleep disorders, as well as neural correlates of sleep disturbances across various neuropsychiatric disorders. In this introductory review, we describe the details of our currently available datasets and our ongoing projects in the ENIGMA-Sleep group, and discuss both the potential challenges and opportunities of a collaborative initiative in sleep medicine

ENIGMA and global neuroscience: A decade of large-scale studies of the brain in health and disease across more than 40 countries

This review summarizes the last decade of work by the ENIGMA (Enhancing NeuroImaging Genetics through Meta Analysis) Consortium, a global alliance of over 1400 scientists across 43 countries, studying the human brain in health and disease. Building on large-scale genetic studies that discovered the first robustly replicated genetic loci associated with brain metrics, ENIGMA has diversified into over 50 working groups (WGs), pooling worldwide data and expertise to answer fundamental questions in neuroscience, psychiatry, neurology, and genetics. Most ENIGMA WGs focus on specific psychiatric and neurological conditions, other WGs study normal variation due to sex and gender differences, or development and aging; still other WGs develop methodological pipelines and tools to facilitate harmonized analyses of "big data" (i.e., genetic and epigenetic data, multimodal MRI, and electroencephalography data). These international efforts have yielded the largest neuroimaging studies to date in schizophrenia, bipolar disorder, major depressive disorder, post-traumatic stress disorder, substance use disorders, obsessive-compulsive disorder, attention-deficit/hyperactivity disorder, autism spectrum disorders, epilepsy, and 22q11.2 deletion syndrome. More recent ENIGMA WGs have formed to study anxiety disorders, suicidal thoughts and behavior, sleep and insomnia, eating disorders, irritability, brain injury, antisocial personality and conduct disorder, and dissociative identity disorder. Here, we summarize the first decade of ENIGMA's activities and ongoing projects, and describe the successes and challenges encountered along the way. We highlight the advantages of collaborative large-scale coordinated data analyses for testing reproducibility and robustness of findings, offering the opportunity to identify brain systems involved in clinical syndromes across diverse samples and associated genetic, environmental, demographic, cognitive, and psychosocial factors

A need for worldwide collaboration in neuroimaging/genetics of sleep research: The ENIGMA-Sleep framework

Recent neuroimaging and genetic evidence have advanced our under-standing of the neurobiological mechanism of sleep physiology, sleepdisorders and the interplay between sleep and neuropsychiatric disor-ders. However, most conventional individual studies have limitations inidentifying reproducible effects due to their small sample sizes, geneticvariability, heterogeneous clinical characteristics, and divergent imag-ing acquisition, preprocessing and analytic methods. Thus, a need for aconsensus multi-centre effort in sleep research is inevitable to increasethe number of samples, and harmonize the methods of data preproces-sing and analysis using the pre-registered unified protocols. Recently,the ENIGMA-Sleep consortium has been launched with the collabora-tion of around 100 scientists across 15 countries to perform large-scaleworldwide neuroimaging and genetics studies in the sleep field. TheENIGMA-Sleep group adopts a‘bottom-up’approach, whereby theinterested researchers can join and suggest/guide a project, rather thanjust contributing to some predetermined set of analyses by sharingdata. Currently, there are several ongoing projects about neural corre-lates of insomnia disorder using structural brain data, the predictiverole of sleep on cognitive performance among population-based sam-ples, predicting brain age gap following sleep deprivation, and trans-diagnostic neural correlates of sleep across mental illnesses

On The Search for Convergence of Functional Brain Patterns across Neuroimaging Studies: A Coordinate-Based Meta-Analysis Using Gibbs Point Process

Introduction: Coordinate-based meta-analysis (CBMA) is a standard method for integrating brain functional patterns in neuroimaging studies. CBMA aims to identify convergency in activated brain regions across studies using coordinates of the peak activation (foci). Here, we aimed to introduce a new application of the Gibbs models for the meta-regression of the neuroimaging studies.Methods: We used a dataset acquired from 31 studies by previous work. For each study as well as foci, study features such as SD duration and the average age were extracted. Two widely Gibbs models, Area-interaction and Geyer saturation were fitted on the foci. These models can quantify and test evidence for clusters in foci using an interaction parameter. We included study features in the models to identify their contribution to foci distribution and hence determine sources of the heterogeneity.Results: Our results revealed that latent study-specific features have a moderate contribution to the heterogeneity of foci distribution. However, the effect of age and SD duration was not significant (p<0.001). Additionally, the estimated interaction parameter was 1.34 (p<0.001) which denotes strong evidence of clusters in foci.Conclusions: Overall, this study highlighted the role of the interaction parameter in CBMA. The results of this work suggest that Gibbs models can be considered as a promising tool for neuroimaging meta-analysi

The Effect of Sleep Deprivation on the Association between Positive Affect and Resting-State Networks

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Imaging executive functions in Parkinson's disease: An activation likelihood estimation meta-analysis

INTRODUCTION:Executive dysfunction is a common and early cognitive symptom in Parkinson's disease (PD) with a detrimental effect on quality of life of patients and their care givers. Thus, a number of neuroimaging studies investigated the underlying neural correlates of such an impairment. Results of individual studies, however, are not univocal in terms of location and directionality of associated functional brain changes.OBJECTIVE:To assess convergence of abnormal brain activation in patients with PD during the performance of tasks probing executive functions (EF).METHODS:We screened the functional imaging literature on EF in PD using the PubMed database, extracted reported stereotactic data and tested for convergence of deviant neural activation in patients with PD when compared to healthy controls (HC) using a coordinate-based activation likelihood estimation approach.RESULTS:We identified 22 eligible papers from which the main proportion was targeted at the investigation of working memory encompassing 354 patients and 306 HC. Surprisingly, no significant converging aberrant activation between HC and patients (ON, OFF or ON + OFF medication, respectively) could be observed when controlling for multiple comparisons using family-wise error correction on cluster-level.CONCLUSION:We conclude that there is currently not enough available evidence to pinpoint a specific neural correlate associated with executive dysfunction in PD. This might be due to the small number of studies performed and their methodical inconsistency. Therefore, it is important to conduct more research regarding functional brain changes associated with EF in these patients using more consistent frameworks and bigger samples

The Association between Alexithymia and Functional Connectivity of Dorsal Anterior Cingulate Cortex

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