Regional cerebral blood flow at rest in obesity

Abstract Background Imaging studies have shown brain abnormalities associated with eating behavior (taste perception, food intake and food reward), neural connectivity and cognition related to obese state. Here, we investigated if obese subjects have changes in regional cerebral blood flow (rCBF) during fasting and rest using Single-photon Emission Tomography (SPECT), and if these differences are associated with body fat and serum levels of leptin, insulin and glucose. Research Methods & Procedures For this purpose, rCBF assessed by (99mTc)-ECD-SPECT was compared between ten obese women (age: 30±5 years, body fat: 38±3 kg) and ten lean women (age: 30±6 years, body fat: 17±5 kg), using Statistical Parametric Mapping. Pearson's coefficient and linear regression were used to search for associations among variables. Results Obese subjects showed antagonic rCBF in the left frontoparietal region and greater rCBF in areas related to the Default Mode Network and the Salience Network (p =0.0001). Positive linear correlations between the rCBF, body fat and the serum levels of glucose and insulin was found, but no associations were detected using linear regression. Conclusion Obese women showed rCBF differences in areas related to the frontoparietal neural circuit, the Default Mode Network and the Salience Network, suggesting loss of cognitive control and a higher perception of physiological processes, such as hunger. Hyperactivation in these areas could jeopardize the recognition of changes in energy homeostasis.