OxCIN Global Scholars + WIP

Bayesian Hierarchical Modeling of Brain Morphometry Across Neurological Disorders in Nigeria

Presented by Patrick Filima

Abstract:This presentation explores the potential of Bayesian hierarchical modeling as a framework for analyzing brain morphometry data across neurological disorders in Nigeria. Neuroimaging datasets from underrepresented populations often face challenges such as small sample sizes, heterogeneity in acquisition, and variability across study groups, which can limit the robustness and generalizability of conventional statistical analyses. In this work(work is still in progress), I examine how hierarchical Bayesian approaches may provide a more flexible and principled way to model such data by accounting for both shared and group-specific sources of variation. The broader aim is to strengthen inference in African neuroimaging research and contribute to more inclusive and globally representative brain science.

WIP presentation for effects of esketamine on different domains of apathy (a fMRI study)

Presented by Sagel Kundieko 

Abstract: Apathy is a marked reduction in motivation and goal-directed behaviour. It is a common and debilitating symptom that can affect both healthy and clinical populations. Despite its wide impact, the mechanisms underlying apathy remain poorly understood, particularly across its distinct behavioural/cognitive, social and emotional domains.

Esketamine is an FDA-approved rapid-acting antidepressant. It acts as an NMDA receptor antagonist that can enhance dopaminergic neurotransmission in striatal and prefrontal circuits. It is postulated that through this mechanism, esketamine reduces symptoms of anhedonia, which is closely related to motivational deficits. Particularly, single-dose administration has been shown to modulate reward-related activity in the nucleus accumbens, putamen, and anterior cingulate cortex. Whether these effects extend to healthy individuals with varying levels of apathy remains unknown.

Fifty healthy volunteers (aged 18 to 45) will be randomly assigned in a double-blind, placebo-controlled, between-subjects design to receive either a single 56 mg intranasal esketamine dose or saline placebo. Task-based 3T fMRI will be completed 24 hours after administration, a window at which acute dissociative effects have fully resolved, and clinical antidepressant effects are typically observed to peak. During scanning, participants will complete three paradigms targeting distinct apathy domains: an effort-based reward task, a cognitive effort task, and a naturalistic story-listening paradigm designed to engage affective processing. Trait apathy will be measured using the Apathy Motivation Index (AMI).

We predict that esketamine will increase BOLD responses in the striatum, anterior cingulate cortex, prefrontal cortex, and insula. This activation will be higher for individuals with higher levels of apathy. Both ROI and whole-brain analyses will be used, the latter allowing exploration of broader neural effects and their correlation with task performance. To our knowledge, this study will provide the first neuroimaging evidence of esketamine's effects on motivation-related brain activity in healthy individuals.