Convergent functional, white-matter microstructural, and cerebral perfusion abnormalities in overweight and obese adults: a multimodal MRI study.

Background: Obesity affects the brain, but most neuroimaging studies examine a single modality, leaving it unclear whether obesity-related functional, microstructural, and perfusion abnormalities co-localize. We combined three modalities across the normal-weight-overweight-obese spectrum. Methods: Of 80 adults enrolled, 10 were excluded (sleep, incomplete acquisition, artifacts), leaving 70 (normal-weight, Results: Obese participants showed lower ALFF than controls in the cerebellar posterior lobe (vermis, left lobule VIII, right Crus II) and left superior frontal gyrus, higher ALFF in the bilateral parahippocampal gyri, lower ReHo in the left superior frontal gyrus, and lower ReHo than overweight participants in the left middle cingulate gyrus. No regional diffusion difference survived FDR correction, but BMI predicted FA, MD, and RD in the right inferior cerebellar peduncle in whole-sample regression (all Conclusion: Overweight and obesity are associated with spatially convergent functional, microstructural, and perfusion abnormalities preferentially involving cerebellar and cortico-limbic regions, scaling continuously with BMI in the right inferior cerebellar peduncle. Because cognition was assessed only by the MMSE, these roles suggest hypotheses rather than conclusions about cognition.