Biology subjects

Connaughton, M.

Publications and source records attributed to Connaughton, M..

4 recordsLinked to original sources

bioRxiv2025

Early life adversity and White Matter Microstructural Organization - a systematic review.

Early life adversity, defined as exposure to stressful events during childhood, is a significant risk factor for the development of psychiatric disorders. Diffusion tensor imaging studies employing tract-based spatial statistics have shown microstructural abnormalities in white matter among individuals exposed to early life adversity; however, robust conclusions are yet to be drawn. This systematic review synthesizes findings of previous tract-based spatial statistics studies to identify the white matter alterations in adult brains exposed to early life adversity, in papers with methodological consistency. The literature search (April 2024) was conducted to identify tract-based spatial statistics studies that compared diffusion metrics between adults exposed to early life adversity and adults not. Embase, Pubmed, and PsycInfo were searched, retrieving 2458 articles. Following deduplication, 1739 titles and/or abstracts were screened. 1699 articles were excluded, and 40 full texts were reviewed. Seven articles, reporting on 764 subjects, met the inclusion criteria and were included in the narrative synthesis. Compared to controls, adults exposed to early life adversity showed lower fractional anisotropy values in white matter tracts of the limbic and visual processing systems, specifically the anterior thalamic radiation, inferior longitudinal fasciculus, corona radiata, uncinate fasciculus, inferior fronto-occipital fasciculus, and cingulum bundle. This systematic review highlights that early life adversity may underlie emotional dysregulation and contribute to an increased risk of psychopathology in later life and explores the potential neurobiological mechanisms that underpin these structural changes. Understanding these associations is crucial for developing targeted interventions aimed at mitigating the long-term impact of early life adversity.

neuroscience↗

bioRxiv2024

Limbic System White Matter in Children and Adolescents with ADHD: A Longitudinal Diffusion MRI Analysis

Attention-deficit/hyperactivity disorder (ADHD) is increasingly recognized as a disorder linked to atypical white matter development across large-scale brain networks. However, current research predominantly focuses on cortical networks, leaving the developmental trajectories of many subcortical networks, including the limbic system, largely unexplored. The limbic system is crucial for emotion and cognition, making it a key area of interest in ADHD research. This study employed multi-shell high angular resolution diffusion magnetic resonance imaging to map the development of limbic system white matter in individuals with ADHD (n = 72) and controls (n = 97) across three time points between ages 9 and 14. Diffusion kurtosis imaging and graph theory metrics were used to characterize limbic system white matter, alongside assessments of emotional regulation and ADHD symptom severity. Compared to controls, individuals with ADHD exhibited significantly lower microstructural organization, particularly in kurtosis anisotropy, within the bilateral cingulum bundle from childhood to adolescence. Brain-behavior analyses further revealed that higher ADHD symptom severity was associated with a lower number of limbic system white matter connections, notably decreased routing efficiency and network density. These findings offer novel insights into the role of disrupted limbic system white matter in ADHD pathophysiology, broadening our understanding of the disorders neural mechanisms and opening promising avenues for future exploration of subcortical brain networks.

neuroscience↗

bioRxiv2024

Bullying and Early Brain Development: A Longitudinal Structural Magnetic Resonance Imaging Study from Adolescence to Early Adulthood

This study investigated associations between bullying victimization and brain development using longitudinal structural MRI data from the IMAGEN cohort (n = 2,094; 1,009 females) across three time points ([~]14, [~]19, and [~]22 years). A data-driven analysis revealed that higher bullying victimization was significantly associated with accelerated volumetric growth in subcortical and limbic regions, including the putamen ({beta} = 0.12, 95% CI: 0.10-0.15), amygdala ({beta} = 0.07, 95% CI: 0.05-0.09), hippocampus ({beta} = 0.06, 95% CI: 0.04- 0.08), and anterior cingulate cortex (caudal: {beta} = 0.05, 95% CI: 0.03-0.07; rostral: {beta} = 0.06, 95% CI: 0.04-0.08). In contrast, bullying victimization was also significantly associated with reduced volumetric growth in the cerebellum ({beta} = -0.09, 95% CI: -0.11 to -0.07), entorhinal cortex ({beta} = -0.10, 95% CI: -0.13 to -0.07), and insula ({beta} = -0.08, 95% CI: -0.11 to -0.06).Exploratory analyses indicated that females exhibited more pronounced changes in emotional processing regions, while males showed greater changes in motor and sensory areas. Overall, the findings indicate that bullying victimization is associated with widespread structural differences in brain development from adolescence to early adulthood, with sex-specific trajectories.

neuroscience↗

bioRxiv2022

Connectome-based predictive modeling of cognitive reserve using task-based functional connectivity

Cognitive reserve supports cognitive function in the presence of pathology or atrophy. Functional neuroimaging may enable direct and accurate measurement of cognitive reserve which could have considerable clinical potential. The present study aimed to develop and validate a measure of cognitive reserve using task-based fMRI data that could then be applied to independent resting-state data. Connectome-based predictive modeling with leave-one-out cross-validation was applied to predict a residual measure of cognitive reserve using task-based functional connectivity from the Cognitive Reserve/Reference Ability Neural Network studies (n = 220, mean age = 51.91 years, SD = 17.04 years). Three network-strength predicted cognitive reserve measures were generated that accurately predicted the residual measures of unseen participants. The theoretical validity of these measures was established via a positive correlation with a socio-behavioural proxy of cognitive reserve (verbal intelligence) and a positive correlation with global cognition, independent of brain structure. This fitted model was then applied to external test data: resting-state functional connectivity data from The Irish Longitudinal Study on Ageing (TILDA, n = 294, mean age = 68.3 years, SD = 7.18 years). The network-strength predicted measures were not positively associated with a residual measure of cognitive reserve nor with measures of verbal intelligence and global cognition. The present study demonstrated that task-based functional connectivity data can be used to generate theoretically valid measures of cognitive reserve. Further work is needed to establish if, and how, measures of cognitive reserve derived from task-based functional connectivity can be applied to independent resting-state data.

neuroscience↗