The Structural and Functional Neuroanatomy of Default Mode Network Disruption in Schizophrenia Among Urban Nigerian Adults: An MRI Connectome Study

Schizophrenia is associated with disruptions in the default mode network, a set of functionally connected cortical regions active during rest and self-referential processing. Structural and functional magnetic resonance imaging evidence from Western populations indicates reduced connectivity between the medial prefrontal cortex, posterior cingulate cortex, and inferior parietal lobule in schizophrenia, but comparable data from sub-Saharan African patient populations are entirely absent. This study aims to characterise default mode network structural and functional connectivity in schizophrenia among adults attending psychiatric services at the University of Lagos Teaching Hospital and Federal Neuro-Psychiatric Hospital Yaba, South West Nigeria. Forty schizophrenic patients and 40 age-, sex-, and education-matched healthy controls will undergo three-dimensional T1-weighted structural MRI and resting-state functional MRI. Voxel-based morphometry will identify grey matter volume differences. Independent component analysis will characterise resting-state functional connectivity within the default mode network. Diffusion tensor imaging will evaluate structural white matter integrity of key default mode network tracts. Results will be analysed in relation to psychopathological severity using Positive and Negative Syndrome Scale scores. This study will generate the first Nigerian connectome dataset for schizophrenia, constituting an original scientific contribution to the global understanding of schizophrenia neuroanatomy and providing a basis for culturally contextualised neuroimaging biomarker research.

Keywords: schizophrenia, default mode network, connectome, resting-state fMRI, Nigeria