Browsing by Author "Gibbard, Ben"
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- ItemOpen AccessBrain Structure and Mental Health Symptoms in Children and Adolescents with Prenatal Alcohol Exposure(2023-06-12) Nakhid, Daphne Kristen Mitchell; Lebel, Catherine; McMorris, Carly; Gibbard, Ben; MacMaster, FrankPrenatal alcohol exposure (PAE) can impact brain development, leading to an increased risk of cognitive difficulties and mental health challenges. Mental health challenges affect many people with PAE, however, associations with brain structure remain unknown. In unexposed populations, mental health symptoms are closely linked to brain volume of subcortical structures and limbic subregions. Whether there is a similar association in individuals with PAE is unknown. Beyond brain volume, iron is a key component of healthy brain development; PAE lowers fetal brain iron and may be associated with the development of mental health symptoms. Whether increased mental health symptoms in youth with PAE are associated with alterations in brain volume or brain iron of subcortical brain structures is yet to be determined. This dissertation used quantitative susceptibility mapping (QSM) and T1-weighted magnetic resonance imaging (MRI) to assess differences in brain iron and brain volume of limbic and subcortical brain regions in youth with and without PAE. Additionally, associations between brain structure and mental health symptoms were assessed within and between groups. Multiple subcortical brain structures and limbic subregions were smaller in the PAE group, but only limbic subregion volume showed associations with mental health symptoms. I found minimal group differences in magnetic susceptibility, a marker of brain iron, but many associations between brain iron and mental health symptoms within and between groups. Furthermore, PAE moderated the association between internalizing symptoms for both brain iron and subnuclei volumes in the thalamus, suggesting that the thalamus may be a unique correlate of mental health symptoms in youth with PAE. This research provides greater insight into limbic subregions that may be affected by PAE that are not observed when looking at the whole volume of a brain region. As the first study to examine magnetic susceptibility in humans with PAE, it provides important information to help understand mental health symptoms in exposed and unexposed populations. This study highlights brain structures and regions that are uniquely associated with mental health symptoms in youth with PAE. Implications of this work include increasing awareness around mental health and promoting appropriate interventions to support youth with PAE.
- ItemOpen AccessThe brain's functional connectome in young children with prenatal alcohol exposure(Elsevier, 2019-01) Long, Xiangyu; Kar, Preeti; Gibbard, Ben; Tortorelli, Christina; Lebel, CatherinePrenatal alcohol exposure (PAE) can lead to altered brain function and structure, as well as lifelong cognitive, behavioral, and mental health difficulties. Previous research has shown reduced brain network efficiency in older children and adolescents with PAE, but no imaging studies have examined brain differences in young children with PAE, at an age when cognitive and behavioral problems often first become apparent. The present study aimed to investigate the brain's functional connectome in young children with PAE using passive viewing fMRI. We analyzed 34 datasets from 26 children with PAE aged 2-7 years and 215 datasets from 87 unexposed typically-developing children in the same age range. The whole brain functional connectome was constructed using functional connectivity analysis across 90 regions for each dataset. We examined intra- and inter-participant stability of the functional connectome, graph theoretical measurements, and their correlations with age. Children with PAE had similar inter- and intra-participant stability to controls. However, children with PAE, but not controls, showed increasing intra-participant stability with age, suggesting a lack of variability of intrinsic brain activity over time. Inter-participant stability increased with age in controls but not in children with PAE, indicating more variability of brain function across the PAE population. Global graph metrics were similar between children with PAE and controls, in line with previous studies in older children. This study characterizes the functional connectome in young children with PAE for the first time, suggesting that the increased brain variability seen in older children develops early in childhood, when participants with PAE fail to show the expected age-related increases in inter-individual stability.