Year: 2025
Type: dissertation
Abstract: Obesity is a major global health problem, associated with increased morbidity and reduced life expectancy. Sustained weight loss via current treatments is challenging. Bariatric surgery is the most effective intervention and Roux-en-Y gastric bypass (RYGB) is the most common procedure, providing significant weight loss, reduced mortality, and fewer obesity-related comorbidities. Obesity affects brain, and bariatric surgery alters neural activity, but research on its effects on resting-state fMRI (rsfMRI) is limited, especially regarding obesity-related functional alteration and surgical reshaping of brain activity under different prandial conditions. This doctoral project aims to explore how obesity, food intake, and RYGB affect resting-state brain activity in females, who are more likely to undergo surgery but underrepresented in prior studies. Analyses used fractional amplitude of low-frequency fluctuations (fALFF) and functional connectivity (FC). All enrolled patients with obesity achieved significant and sustained weight loss following RYGB. In Paper I, pre-surgery female patients with obesity exhibited higher fALFF in reward-related brain regions compared to normal-weight females, independent of prandial condition. Paper II showed reduced fALFF in several brain regions four weeks after RYGB, including those associated with reward, with prandial-dependent effects, indicating rapid surgical modulation. Paper IV showed decreased fALFF in brain regions associated with emotion, visual processing, and reward at short- and long-term post-surgical follow-ups, regardless of prandial condition, suggesting sustained RYGB-induced changes in brain function. Paper III found an early impact on reward processing regions and a slow effect on regions involved in cognitive control over eating, indicating short- and long-term effects of RYGB. Additionally, pre-surgery FC in emotional control and social interaction areas was positively correlated with one-year post-surgical BMI reduction. Overall, these findings enhance understanding of obesity and food intake’s impact on female resting-state brain activity, demonstrating RYGB’s rapid and sustained effect on the resting-state brain activity and potential normalization of obesity-associated neural alterations.
Author: Zhou, Wei
Institutions: Linköping University, Uppsala University
Language: English
Subfield: Surgery
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W7112181650