Adverse childhood experiences predict neurite density differences in young children with and without attention deficit hyperactivity disorder

From bench to bedside: Overview of magnetoencephalography in basic principle, signal processing, source localization and clinical applications

Magnetoencephalography (MEG) is a non-invasive technique that can precisely capture the dynamic spatiotemporal patterns of the brain by measuring the magnetic fields arising from neuronal activity along the order of milliseconds. Observations of brain dynamics have been used in cognitive neuroscience, the diagnosis of neurological diseases, and the brain-computer interface (BCI). In this study, we outline the basic principle, signal processing, and source localization of MEG, and describe its clinical applications for cognitive assessment, the diagnoses of neurological diseases and mental disorders, preoperative evaluation, and the BCI. This review not only provides an overall perspective of MEG, ranging from practical techniques to clinical applications, but also enhances the prevalent understanding of neural mechanisms. The use of MEG is expected to lead to significant breakthroughs in neuroscience.

Stress as a mediator of brain alterations in attention-deficit hyperactivity disorder: A systematic review

OBJECTIVE

Stress is a known risk factor for numerous psychopathologies, whereas evidence is lacking regarding the specific consequences of stress on the neural basis of attention-deficit hyperactivity disorder (ADHD). A systematic literature review was thus conducted to clarify the role of stress in the association between the resulting alterations of brain structure, connectivity, and function in ADHD.

METHODS

The study was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and the protocol was registered in the International Prospective Register of Systematic Reviews (PROSPERO) under identifier CRD42023379809. A systematic search of the PubMed and CINAHL databases was conducted for articles published prior to December 22nd, 2022. Retrieved literature was screened in Rayyan and data extraction was performed with respect to neuroimaging, stress exposure, and ADHD outcomes. The Quality in Prognosis Studies (QUIPS) tool was adapted based on the Conducting Systematic Reviews and Meta-Analyses of Observational Studies of Etiology (COSMOS-E) guidance article to assess risk of bias and quality of studies. Strength of the evidence was assessed under the guidance of the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system.

RESULTS

Screening 25,026 non-duplicate articles yielded 20 eligible studies for inclusion. Exposure to early life trauma, institutionalization, prenatal smoking or alcohol consumption, air pollution, low socioeconomic status, or low birth weight were associated with alterations in brain structure, function, and connectivity in ADHD. However, most studies did not provide strong evidence due to small sample sizes and lack of statistical approaches to determine a direct mediation of the association between stress and ADHD by neural outcomes.

CONCLUSION

This systematic review was the first to summarize evidence of structural and functional stress-associated alterations in the brain, which were found to be directly and indirectly associated with ADHD outcomes. Overall, stress requires consideration as a significant determinant of neurodevelopmental outcomes in ADHD. However, extensive further research is warranted due to little available evidence and the difficulty of obtaining clear results. In light of such a complex research question, in order to confirm findings, provide further evidence, and establish causality systematic longitudinal studies would be required. Investigating the topic may provide invaluable information when it comes to tailoring prevention and treatment strategies in ADHD, and should be pursued in order to integrate the factor of stress into a more comprehensive understanding of ADHD.

Functional contribution of the intestinal microbiome in autism spectrum disorder, attention deficit hyperactivity disorder, and Rett syndrome: a systematic review of pediatric and adult studies

Introduction

Critical phases of neurodevelopment and gut microbiota diversification occur in early life and both processes are impacted by genetic and environmental factors. Recent studies have shown the presence of gut microbiota alterations in neurodevelopmental disorders. Here we performed a systematic review of alterations of the intestinal microbiota composition and function in pediatric and adult patients affected by autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), and Rett syndrome (RETT).

Methods

We searched selected keywords in the online databases of PubMed, Cochrane, and OVID (January 1980 to December 2021) with secondary review of references of eligible articles. Two reviewers independently performed critical appraisals on the included articles using the Critical Appraisal Skills Program for each study design.

Results

Our systematic review identified 18, 7, and 3 original articles describing intestinal microbiota profiles in ASD, ADHD, and RETT, respectively. Decreased Firmicutes and increased Bacteroidetes were observed in the gut microbiota of individuals affected by ASD and ADHD. Proinflammatory cytokines, short-chain fatty acids and neurotransmitter levels were altered in ASD and RETT. Constipation and visceral pain were related to changes in the gut microbiota in patients affected by ASD and RETT. Hyperactivity and impulsivity were negatively correlated with Faecalibacterium (phylum Firmicutes) and positively correlated with Bacteroides sp. (phylum Bacteroidetes) in ADHD subjects. Five studies explored microbiota-or diet-targeted interventions in ASD and ADHD. Probiotic treatments with Lactobacillus sp. and fecal microbiota transplantation from healthy donors reduced constipation and ameliorated ASD symptoms in affected children. Perinatal administration of Lactobacillus sp. prevented the onset of Asperger and ADHD symptoms in adolescence. Micronutrient supplementation improved disease symptomatology in ADHD without causing significant changes in microbiota communities' composition.

Discussion

Several discrepancies were found among the included studies, primarily due to sample size, variations in dietary practices, and a high prevalence of functional gastrointestinal symptoms. Further studies employing longitudinal study designs, larger sample sizes and multi-omics technologies are warranted to identify the functional contribution of the intestinal microbiota in developmental trajectories of the human brain and neurobehavior.

Systematic review registration

https://clinicaltrials.gov/, CRD42020158734.

Parental Deprivation- and Threat-Based Factors Associated with Youth Emotion-Based Neurocircuitry and Externalizing Behavior: A Systematic Review

Parental factors, including negative parenting practices (e.g., family conflict, low monitoring), parental depression, and parental substance use, are associated with externalizing behaviors among youth. However, the ways in which these parental factors are associated with youth brain function and consequent externalizing behavior has been less studied. Both the dimensional and stress acceleration models provide frameworks for understanding how parental factors may be associated with frontolimbic and frontoparietal networks implicated in emotional attention and regulation processes. The current review builds upon this work by examining how deprivation- and threat-based parental factors are associated with youth neurocircuitry involved in emotional functioning and externalizing behaviors. A systematic review using PRISMA guidelines was completed and included five studies assessing parenting behaviors, six studies assessing parental depressive symptoms and/or diagnosis, and 12 studies assessing parental history of substance use. Synthesis of reviewed studies discusses support for the dimensional and stress acceleration models within the context of deprivation and threat. Further, a limited number of studies tested (i.e., six studies) and supported (i.e., three studies) youth neural structure and function as a mediator of the association between parental factors and youth externalizing behavior. Specific recommendations for future work include more deliberate planning related to sample composition, improved clarity related to parental constructs, consistency in methodology, and longitudinal study design in order to better understand associations between contextual parental influences and youth neural and behavioral functioning.

Applications of advanced diffusion MRI in early brain development: a comprehensive review

Brain development follows a protracted developmental timeline with foundational processes of neurodevelopment occurring from the third trimester of gestation into the first decade of life. Defining structural maturational patterns of early brain development is a critical step in detecting divergent developmental trajectories associated with neurodevelopmental and psychiatric disorders that arise later in life. While considerable advancements have already been made in diffusion magnetic resonance imaging (dMRI) for pediatric research over the past three decades, the field of neurodevelopment is still in its infancy with remarkable scientific and clinical potential. This comprehensive review evaluates the application, findings, and limitations of advanced dMRI methods beyond diffusion tensor imaging, including diffusion kurtosis imaging (DKI), constrained spherical deconvolution (CSD), neurite orientation dispersion and density imaging (NODDI) and composite hindered and restricted model of diffusion (CHARMED) to quantify the rapid and dynamic changes supporting the underlying microstructural architectural foundations of the brain in early life.