FV10. Gastric-bypass surgery induced widespread neural plasticity of the obese human brain

Abstract

Bariatric surgery has become the gold standard for the treatment of morbid obesity (body mass index (BMI) ⩾ 40 kg/m2), but its plastic influences on the obese brain remain largely unexplored. Here, we combined structural and functional magnetic resonance brain imaging (MRI) in twenty-seven patients (BMI 47.8 ± 5.5 kg/m2) undergoing gastric-bypass surgery and fourteen non-obese controls (BMI 24.7 ± 3.4 kg/m2). Over the first year after surgery, patients presented changes in gray matter density (GMD) in the cerebral cortex of all lobes, subcortical structures as well as the cerebellum, but no changes in white matter water diffusivity throughout the brain. Related to the BMI loss, we identified altered GMD in the hypothalamus, the brain’s homeostatic control site, the lateral orbitofrontal cortex, assumed to host reward and gustatory processes, as well as bilateral abdominal representations in somatosensory cortex. Voxel-by-voxel regression analyses revealed that all GMD changes were associated with elevated regional homogeneity of spontaneous neural activity (ReHo) in blood-oxygenation level-dependent signals. Spatial–temporal integration of structural and functional MRI suggests that gastric-bypass surgery induced widespread plastic changes in cortical structure that concurrently homogenized the functional profile of the cortex.