Structural Brain Connectivity in Childhood Disruptive Behavior Problems: A Multidimensional Approach

Early morning physical activity is associated with healthier white matter microstructure and happier children: the ActiveBrains project

The background of this study is to examine the associations of individual and combined early morning patterns (i.e., active commuting to school, physical activity before school, having breakfast and good sleep) with white matter microstructure (WMM) and, whether the associated white mater microstructure outcomes were related to mental health outcomes in children with overweight or obesity. 103 children with overweight or obesity (10.0 ± 1.1 years old, 42 girls) from the ActiveBrains project participated in this cross-sectional study. Early morning patterns and mental health indicators (i.e., self-esteem, optimism, positive and negative affect, stress, depression and anxiety) were self-reported by the children using validated questionnaires. WMM was assessed by magnetic resonance imaging using diffusion tensor imaging. When examined independently, early morning patterns were not related with WMM (all P > 0.05). However, the combination of early morning patterns was related with WMM (P < 0.05). Specifically, physically active early morning patterns (i.e., active commuting to school and physical activity before school) were associated with global fractional anisotropy (FA) (β = 0.298, P = 0.013) and global radial diffusivity (RD) (β = - 0.272, P = 0.021), as well as with tract-specific FA (β = 0.314, P = 0.004) and RD (β = - 0.234, P = 0.032) in the superior longitudinal fasciculus (SLF). Furthermore, combined physically active early morning pattern-associated global (i.e., FA and RD) and tract-specific (i.e., FA and RD in the SLF) WMM indicators were positively associated with happiness (β absolute value range from 0.252 to 0.298, all P < 0.05). A combination of physically active early morning patterns may positively relate to white matter microstructure in children with overweight or obesity, and, in turn, happiness.

Impact of prenatal marijuana exposure on adolescent brain structural and functional connectivity and behavioural outcomes

There has been an increase in the number of women using marijuana whilst pregnant. Previous studies have shown that children with prenatal marijuana exposure have developmental deficits in memory and decreased attentiveness. In this study, we assess whether prenatal marijuana exposure is associated with alterations in brain regional morphometry and functional and structural connectivity in adolescents. We downloaded behavioural scores and subject image files from the Adolescent Brain Cognitive DevelopmentSM Study. A total of 178 anatomical and diffusion magnetic resonance imaging files (88 prenatal marijuana exposure and 90 age- and gender-matched controls) and 152 resting-state functional magnetic resonance imaging files (76 prenatal marijuana exposure and 76 controls) were obtained. Behavioural metrics based on the parent-reported child behavioural checklist were also obtained for each subject. The associations of prenatal marijuana exposure with 17 subscales of the child behavioural checklist were calculated. We assessed differences in brain morphometry based on voxel-based and surface-based morphometry in adolescents with prenatal marijuana exposure versus controls. We also evaluated group differences in structural and functional connectivity in adolescents for region-to-region connectivity and graph theoretical metrics. Interactions of prenatal marijuana exposure and graph networks were assessed for impact on behavioural scores. Multiple comparison correction was performed as appropriate. Adolescents with prenatal marijuana exposure had greater abnormal or borderline child behavioural checklist scores in 9 out of 17 subscales. There were no significant differences in voxel- or surface-based morphometry, structural connectivity or functional connectivity between prenatal marijuana exposure and controls. However, there were significant differences in prenatal marijuana exposure-graph network interactions with respect to behavioural scores. There were three structural prenatal marijuana exposure-graph network interactions and seven functional prenatal marijuana exposure-graph network interactions that were significantly associated with behavioural scores. Whilst this study was not able to confirm anatomical or functional differences between prenatal marijuana exposure and unexposed pre-adolescent children, there were prenatal marijuana exposure-brain structural and functional graph network interactions that were significantly associated with behavioural scores. This suggests that altered brain networks may underlie behavioural outcomes in adolescents with prenatal marijuana exposure. More work needs to be conducted to better understand the prognostic value of brain structural and functional network measures in prenatal marijuana exposure.

Long-term associations between early-life family functioning and preadolescent white matter microstructure

BACKGROUND

Causes of childhood behavior problems remain poorly understood. Enriched family environments and corresponding brain development may reduce the risk of their onset, but research investigating white matter neurodevelopmental pathways explaining associations between the family environment and behavior remains limited. We hypothesized that more positive prenatal and mid-childhood family functioning - a measure of a family's problem solving and supportive capacity - would be associated with two markers of preadolescent white matter neurodevelopment related to reduced behavior problems: higher global fractional anisotropy (FA) and lower global mean diffusivity (MD).

METHODS

Data are from 2727 families in the Generation R Study, the Netherlands. Mothers reported family functioning (McMaster Family Assessment Device, range 1-4, higher scores indicate healthier functioning) prenatally and in mid-childhood (mean age 6.1 years). In preadolescence (mean age 10.1), the study collected diffusion-weighted scans. We computed standardized global MD and FA values by averaging metrics from 27 white matter tracts, and we fit linear models adjusting for possible confounders to examine global and tract-specific outcomes.

RESULTS

Prenatal and mid-childhood family functioning scores were moderately correlated, r = 0.38. However, only prenatal family functioning - and not mid-childhood functioning - was associated with higher global FA and lower global MD in preadolescence in fully adjusted models: βglobal FA = 0.11 (95% CI 0.00, 0.21) and βglobal MD = -0.15 (95% CI -0.28, -0.03) per one-unit increase in functioning score. Sensitivity and tract-specific analyses supported these global findings.

CONCLUSIONS

These results suggest high-functioning prenatal or perinatal family environments may confer lasting white matter neurodevelopmental benefits into preadolescence.

Unilaterally disrupted structural and functional connectivity of the fronto-limbic system in idiopathic hypogonadotropic hypogonadism

OBJECTIVE

Idiopathic hypogonadotropic hypogonadism (IHH) is rare and can either be associated with normal or defective olfactory sensation, classified as normosmic IHH (nIHH) or Kallmann syndrome (KS). We do not yet understand the central processing pathways in the olfactory system. We aimed to compare the resting-state structural and functional connectivity (FC) of olfactory neural pathways in patients with IHH. We hypotheses that alterations of structural connectivity and FC may exist in the olfactory cortex pathways in IHH patients.

DESIGN

STRUCTURAL AND FUNCTIONAL CONNECTIVITY DATA RESULTS BETWEEN TWO GROUPS WERE ANALYZED: Patients: Twenty-five IHH patients (13 nIHH patients and 12 KS patients) were recruited from the Department of Endocrinology and were assessed. A total of 25 age-matched healthy male controls were recruited from the community.

MEASUREMENTS

All subjects underwent diffusion tensor imaging and functional magnetic resonance imaging (fMRI) scans. Structural and functional connectivity data analyses were then performed. Pearson's correlation analyses were performed to investigate the correlations between the fractional anisotropy (FA) value and FC strength, showing significant differences among the three groups separately.

RESULTS

Compared with the HC group, FA value in the right uncinate fasciculus (UF) decreased significantly in the IHH group. The olfactory cortex FC values of the right gyrus rectus, orbitofrontal cortex (OFC) and right middle temporal gyrus in the IHH group were decreased compared with those in the HC group. Moreover, there were significant negative correlations between right UF FA and olfactory cortex-FC to both the gyrus rectus and OFC within the HC group (p &lt; .05).

CONCLUSION

Our findings suggest that alterations of structural and FC support the presence of neurobiological disruptions in IHH patients, particularly a specific structural-functional asymmetry disruption may exist in the olfactory cortex pathways in IHH patients.

Developmental patterning of irritability enhances prediction of psychopathology in preadolescence: Improving RDoC with developmental science

The transdiagnostic importance of irritability in psychopathology has been demonstrated. However, the contribution of developmentally unfolding irritability patterns to specific clinical and neural outcomes remains an important and unanswered question. To address this gap in the literature, irritability patterns of 110 youth from a large, diverse cohort were assessed at preschool age and again at early school age (∼2.5 years later) with a dimensional irritability scale designed to capture the normal:abnormal spectrum. At preadolescence (∼6 years later), clinical outcomes (internalizing/externalizing symptoms) derived from a semistructured clinical interview and neural outcomes (characterized as gray-matter-volume abnormalities) were assessed. For clinical outcomes, preschool-age irritability alone was a transdiagnostic predictor of internalizing and externalizing symptoms at preadolescence. However, in a model including both preschool and early school age, irritability provided greater specificity, suggesting that higher irritability at early school age related to elevated preadolescent externalizing but not internalizing symptoms. In terms of neural outcomes, elevated preschool irritability did not predict preadolescent gray-matter-volume abnormality; however, irritability at early school age demonstrated an interactive effect among regions, with reduced volume in preadolescence emotional regions (e.g., amygdala, medial orbitofrontal cortex) and increased volume in other regions (e.g., cerebellum). These complex patterns highlight the contribution of a developmentally informed approach, the National Institute of Mental Health's Research Domain Criteria (RDoC) approach, to yield transdiagnostic phenotypes and multiple units of analysis. Capturing these individual differences and developmental heterogeneity can provide critical insight into the unfolding of mechanisms underlying emerging psychopathology. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Multivariate Genetic Structure of Externalizing Behavior and Structural Brain Development in a Longitudinal Adolescent Twin Sample

Externalizing behavior in its more extreme form is often considered a problem to the individual, their families, teachers, and society as a whole. Several brain structures have been linked to externalizing behavior and such associations may arise if the (co)development of externalizing behavior and brain structures share the same genetic and/or environmental factor(s). We assessed externalizing behavior with the Child Behavior Checklist and Youth Self Report, and the brain volumes and white matter integrity (fractional anisotropy [FA] and mean diffusivity [MD]) with magnetic resonance imaging in the BrainSCALE cohort, which consisted of twins and their older siblings from 112 families measured longitudinally at ages 10, 13, and 18 years for the twins. Genetic covariance modeling based on the classical twin design, extended to also include siblings of twins, showed that genes influence externalizing behavior and changes therein (h² up to 88%). More pronounced externalizing behavior was associated with higher FA (observed correlation r_ph up to +0.20) and lower MD (r_ph up to −0.20), with sizeable genetic correlations (FA r_a up to +0.42; MD r_a up to −0.33). The cortical gray matter (CGM; r_ph up to −0.20) and cerebral white matter (CWM; r_ph up to +0.20) volume were phenotypically but not genetically associated with externalizing behavior. These results suggest a potential mediating role for global brain structures in the display of externalizing behavior during adolescence that are both partially explained by the influence of the same genetic factor.

Dimensional Analysis of Atypical Functional Connectivity of Major Depression Disorder and Bipolar Disorder

Literatures have reported considerable heterogeneity with atypical functional connectivity (FC) pattern of psychiatric disorders. However, traditional statistical methods are hard to explore this heterogeneity pattern. We proposed a "brain dimension" method to describe the atypical FC patterns of major depressive disorder and bipolar disorder (BD). The approach was firstly applied to a simulation dataset. It was then utilized to a real resting-state functional magnetic resonance imaging dataset of 47 individuals with major depressive disorder, 32 individuals with BD, and 52 well matched health controls. Our method showed a better ability to extract the FC dimensions than traditional methods. The results of the real dataset revealed atypical FC dimensions for major depressive disorder and BD. Especially, an atypical FC dimension which exhibited decreased FC strength of thalamus and basal ganglia was found with higher severity level of individuals with BD than the ones with major depressive disorder. This study provided a novel "brain dimension" method to view the atypical FC patterns of major depressive disorder and BD and revealed shared and specific atypical FC patterns between major depressive disorder and BD.

White Matter Microstructure in the Young Adult Brain Varies with Neighborhood Disadvantage in Adolescence

Neighborhood disadvantage and community violence are common in poor, urban communities and are risk factors for emotional dysfunction. Emotional processes are supported by neural circuitry that includes the prefrontal cortex (PFC), hippocampus, amygdala, and hypothalamus. These brain regions are connected by white matter pathways that include the cingulum bundle, uncinate fasciculus, stria terminalis, and fornix. Emotional function varies with the microstructure of these white matter pathways. However, it is not clear whether the microstructure of these pathways varies with risk factors for emotional dysfunction (e.g., neighborhood disadvantage and violence exposure). Therefore, determining the relationships between neighborhood disadvantage, violence exposure, and white matter microstructure may offer insight into the neural mechanisms by which adverse life experiences alter developing neural systems. The current study investigated the association that exposure to neighborhood disadvantage and violence have with the quantitative anisotropy (QA), a measure of the amount of directional water diffusion, of the cingulum bundle, uncinate fasciculus, stria terminalis, and fornix. Neighborhood disadvantage (M_age = 11.20) and violence exposure (M_W1age = 11.20; M_W2age = 13.05; M_W3age = 16.20; M_W4age = 19.25) were assessed during adolescence and participants returned for magnetic resonance imaging as young adults (N = 303; M_age = 20.25, SD = 1.55), during which diffusion weighted brain images were collected. The QA of the cingulum bundle, uncinate fasciculus, and stria terminalis/fornix varied negatively with neighborhood disadvantage such that the QA of these white matter tracts decreased as neighborhood disadvantage increased. Violence exposure was not related to QA in any tract (i.e., cingulum bundle, uncinate fasciculus, and stria terminalis/fornix) after correction for multiple comparisons. These results suggest that an adolescent's neighborhood may play an important role in the microstructure (i.e., QA) of white matter pathways that connect brain regions that support emotional function.

Childhood conduct problems are associated with reduced white matter fibre density and morphology

Childhood conduct problems are an important public health issue as these children are at-risk of adverse outcomes. Studies using diffusion Magnetic Resonance Imaging (dMRI) have found that conduct problems in adults are characterised by abnormal white-matter microstructure within a range of white matter pathways underpinning socio-emotional processing, while evidence within children and adolescents has been less conclusive based on non-specific diffusion tensor imaging metrics. Fixel-based analysis (FBA) provides measures of fibre density and morphology that are more sensitive to developmental changes in white matter microstructure. The current study used FBA to investigate whether childhood conduct problems were related both cross-sectionally and longitudinally to microstructural alterations within the fornix, inferior fronto-occipital fasciculus (IFOF), inferior longitudinal fasciculus (ILF), superior longitudinal fasciculus (SLF), and the uncinate fasciculus (UF). dMRI data was obtained for 130 children across two time-points in a community sample with high levels of externalising difficulties (age: time-point 1 = 9.47 - 11.86 years, time-point 2 = 10.67 -13.45 years). Conduct problems were indexed at each time-point using the Conduct Problems subscale of the parent-informant Strengths and Difficulties Questionnaire (SDQ). Conduct problems were related to lower fibre density in the fornix at both time-points, and in the ILF at time-point 2. We also observed lower fibre cross-section in the UF at time-point 1. The change in conduct problems did not predict longitudinal changes in white-matter microstructure across time-points. The current study suggests that childhood conduct problems are related to reduced fibre-specific microstructure within white matter fibre pathways implicated in socio-emotional functioning.

White Matter Microstructure in Pediatric Bipolar Disorder and Disruptive Mood Dysregulation Disorder

OBJECTIVE

Disruptive mood dysregulation disorder (DMDD) codifies severe, chronic irritability. Youths with bipolar disorder (BD) also present with irritability, but with an episodic course. To date, it is not clear whether aberrant white matter microstructure-a well-replicated finding in BD-can be observed in DMDD and relates to symptoms of irritability.

METHOD

We acquired diffusion tensor imaging data from 118 participants (BD = 36, DMDD = 44, healthy volunteers (HV = 38). Images of fractional anisotropy (FA), axial diffusivity (AD), and radial diffusivity (RD) were processed with tract-based spatial statistics controlling for age and sex. The data were also used to train Gaussian process classifiers to predict diagnostic group.

RESULTS

In BD vs DMDD, FA in the corticospinal tract was reduced. In DMDD vs HV, reductions in FA and AD were confined to the anterior corpus callosum. In BD vs HV, widespread reductions in FA and increased RD were observed. FA in the anterior corpus callosum and corticospinal tract was negatively associated with irritability. The Gaussian process classifier could not discriminate between BD and DMDD, but achieved 68% accuracy in predicting DMDD vs HV and 75% accuracy in predicting BD vs HV.

CONCLUSION

Aberrant white matter microstructure was associated with both categorical diagnosis and the dimension of irritability. Alterations in DMDD were regionally discrete and related to reduced AD. In BD, we observed widespread increases in RD, supporting the hypothesis of altered myelination in BD. These findings will contribute to the pathophysiological understanding of DMDD and its differentiation from BD.

CLINICAL TRIAL REGISTRATION INFORMATION

Studies of Brain Function and Course of Illness in Pediatric Bipolar Disorder; https://clinicaltrials.gov/; NCT00025935; Child & Adolescent Bipolar Disorder Brain Imaging and Treatment Study; https://clinicaltrials.gov/; NCT00006177.

Fixel-Based Diffusion Magnetic Resonance Imaging Reveals Novel Associations Between White Matter Microstructure and Childhood Aggressive Behavior

BACKGROUND

Childhood aggression has been linked to white matter abnormalities, but research has been inconsistent with regard to both regions of alterations and directionality of the associations. We examined white matter microstructure correlates of aggression using a novel diffusion imaging analysis technique, fixel-based analysis, which leverages connectivity and crossing-fiber information to assess fiber bundle density.

METHODS

The sample included 70 children with aggressive behavior and 25 healthy control children without aggressive behavior. Aggression was measured by the parent-rated Aggressive Behavior scale of the Child Behavior Checklist. Fixel-based analysis was conducted at the whole-brain and region-of-interest levels, including the uncinate fasciculus, inferior longitudinal fasciculus, fornix, cingulum bundle, and genu, body, isthmus, and splenium of the corpus callosum.

RESULTS

Whole-brain analysis of covariance revealed that children with aggressive behavior, relative to control children, had lower fiber density in a cluster of limbic and cortical pathways, including the inferior fronto-occipital fasciculus, fornix, middle cerebellar peduncle, and superior thalamic radiations (familywise error-corrected p < .01), and had higher fiber density in the corpus callosum (body and splenium) (familywise error-corrected p < .05). Region-of-interest analyses showed decreased fiber density in cingulum bundles associated with aggression. These effects were independent of age, sex, IQ, symptoms of attention-deficit/hyperactivity disorder, medications, and head motion. In children with aggressive behavior, co-occurring callous-unemotional traits and anxiety did not moderate the association between aggression and white matter density.

CONCLUSIONS

Diminished white matter density in pathways connecting limbic and cortical regions is associated with childhood aggression. Abnormal interhemispheric connectivity via corpus callosum may also reflect a potential neural mechanism involved in aggression.

Sex differences in antisocial and aggressive disorders that onset in childhood and persist into adulthood

As many as 10.7% of males and 7.5% of females display early-onset, stable, antisocial and aggressive behavior (ESAAB). Most research has focused on males. These individuals are diagnosed with conduct disorder in childhood and antisocial personality disorder in adulthood, and a very few, almost all males, present the syndrome of psychopathy. ESAAB includes three subgroups: (1) conduct problems and callousness; (2) conduct problems, callousness, and anxiety; and (3) conduct problems. Heritability of the first two subtypes is high. This high heritability derives, at least in part, from genes involved in regulating serotonergic functioning early in life and to genotypes that confer sensitivity to trauma. The first subtype is rare and characterized by difficulty in face emotion recognition, especially fear and sadness, and hypoarousal as indexed by both autonomic and neural measures, and by structural brain abnormalities. By contrast, those with conduct problems, callousness, and anxiety are more common. They include a greater proportion of females and show hypersensitivity to threat that triggers reactive aggression and that is reflected in both autonomic and neural functioning. In sum, fewer females than males present ESAAB, but many characteristics, autonomic and neural correlates, and etiology are similar. Importantly, however, females with ESAAB play a critical role in the intergenerational transfer of antisocial behavior. Despite higher prevalence of EASSB in males than females, few sex differences in neural abnormalities have been identified.

Antisocial behavior with callous-unemotional traits is associated with widespread disruptions to white matter structural connectivity among low-income, urban males

Antisocial behavior (AB), including violence, criminality, and substance abuse, is often linked to deficits in emotion processing, reward-related learning, and inhibitory control, as well as their associated neural networks. To better understand these deficits, the structural connections between brain regions implicated in AB can be examined using diffusion tensor imaging (DTI), which assesses white matter microstructure. Prior studies have identified differences in white matter microstructure of the uncinate fasciculus (UF), primarily within offender samples. However, few studies have looked beyond the UF or determined whether these relationships are present dimensionally across the range of AB and callous-unemotional (CU) traits. In the current study, we examined associations between AB and white matter microstructure from major fiber tracts, including the UF. Further, we explored whether these associations were specific to individuals high on CU traits. Within a relatively large community sample of young adult men from low-income, urban families (N = 178), we found no direct relations between dimensional, self-report measures of either AB or CU traits and white matter microstructure. However, we found significant associations between AB and white matter microstructure of several tracts only for those with high co-occurring levels of CU traits. In general, these associations did not differ according to race, socioeconomic status, or comorbid psychiatric symptoms. The current results suggest a unique neural profile of severe AB in combination with CU traits, characterized by widespread differences in white matter microstructure, which differs from either AB or CU traits in isolation and is not specific to hypothesized tracts (i.e., the UF).

White matter microstructure correlates of general and specific second-order factors of psychopathology

Increasing data indicate that prevalent forms of psychopathology can be organized into second-order dimensions based on their correlations, including a general factor of psychopathology that explains the common variance among all disorders and specific second-order externalizing and internalizing factors. Nevertheless, most existing studies on the neural correlates of psychopathology employ case-control designs that treat diagnoses as independent categories, ignoring the highly correlated nature of psychopathology. Thus, for instance, although perturbations in white matter microstructure have been identified across a range of mental disorders, nearly all such studies used case-control designs, leaving it unclear whether observed relations reflect disorder-specific characteristics or transdiagnostic associations. Using a representative sample of 410 young adult twins oversampled for psychopathology risk, we tested the hypothesis that some previously observed relations between white matter microstructure properties in major tracts and specific disorders are related to second-order factors of psychopathology. We examined fractional anisotropy (FA), radial diffusivity (RD), and axial diffusivity (AD). White matter correlates of all second-order factors were identified after controlling for multiple statistical tests, including the general factor (FA in the body of the corpus callosum), specific internalizing (AD in the fornix), and specific externalizing (AD in the splenium of the corpus callosum, sagittal stratum, anterior corona radiata, and internal capsule). These findings suggest that some features of white matter within specific tracts may be transdiagnostically associated multiple forms of psychopathology through second-order factors of psychopathology rather with than individual mental disorders.