Publications by authors named "Leah Braganza"

Background: Inter-individual variability in neurobiological and clinical characteristics in mental illness is often overlooked by classical group-mean case-control studies. Studies using normative modelling to infer person-specific deviations of grey matter volume have indicated that group means are not representative of most individuals. The extent to which this variability is present in white matter morphometry, which is integral to brain function, remains unclear.

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Article Synopsis
  • Traditional case-control research overlooks the individual differences in gray matter volume (GMV) among people with mental illness, focusing instead on group averages.
  • A study analyzing 1,294 individuals with six mental health disorders found that less than 7% of participants with the same diagnosis showed similar GMV deviations in specific brain areas, highlighting significant heterogeneity.
  • However, up to 56% of cases shared common functional networks, suggesting that while individuals may differ in specific brain anomalies, they often exhibit similarities in how these issues affect brain function across various disorders.
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Obsessive-compulsive disorder (OCD) and pathological gambling (PG) are accompanied by deficits in behavioural flexibility. In reinforcement learning, this inflexibility can reflect asymmetric learning from outcomes above and below expectations. In alternative frameworks, it reflects perseveration independent of learning.

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The global online education sector has been rising rapidly, particularly during and after the events of 2020, and is becoming mainstream much sooner than expected. Despite this, research studies report higher levels of perceived isolation, difficulties with engagement, and higher attrition rates in online compared to equivalent on-campus programs. Reasons include restrictions to the type of institutional support accessible by online students, and the lack of comprehensiveness of orientation resources.

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Recent neuroimaging studies in OCD have reported structural alterations in the brain, not limited to frontostriatal regions. While Diffusion Tensor Imaging (DTI) is typically used to interrogate WM microstructure in OCD, additional imaging metric, such as Magnetization Transfer Imaging (MTI), allows for further identification of subtle but important structural changes across both GM and WM. In this study, both MTI and DTI were utilised to investigate the structural integrity of the brain, in OCD in relation to healthy controls.

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Individual differences in impulsivity and compulsivity is thought to underlie vulnerability to a broad range of disorders and are closely tied to cortical-striatal-thalamic-cortical function. However, whether impulsivity and compulsivity in clinical disorders is continuous with the healthy population and explains cortical-striatal-thalamic-cortical dysfunction across different disorders remains unclear. Here, we characterized the relationship between cortical-striatal-thalamic-cortical effective connectivity, estimated using dynamic causal modelling of resting-state functional magnetic resonance imaging data, and dimensional phenotypes of impulsivity and compulsivity in two symptomatically distinct but phenotypically related disorders, obsessive-compulsive disorder and gambling disorder.

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