The obese brain: Association of body mass index and insulin sensitivity with resting state network functional connectivity

• Published in: Human brain mapping Vol. 33; no. 5; pp. 1052 - 1061
• Main Authors: Kullmann, Stephanie, Heni, Martin, Veit, Ralf, Ketterer, Caroline, Schick, Fritz, Häring, Hans-Ulrich, Fritsche, Andreas, Preissl, Hubert
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01.05.2012; Wiley-Liss; John Wiley & Sons, Inc
• Subjects: Adult; Biological and medical sciences; Body Mass Index; Brain - physiology; Electrodiagnosis. Electric activity recording; Female; fMRI; food; Humans; independent component analysis (ICA); insulin; Insulin Resistance - physiology; Investigative techniques, diagnostic techniques (general aspects); Magnetic Resonance Imaging - methods; Male; Medical sciences; Nerve Net - physiology; Nervous system; obesity; Obesity - physiopathology; Radiodiagnosis. Nmr imagery. Nmr spectrometry; Rest - physiology; reward; Young Adult; Obesity; Pancreatic hormone; Nervous system diseases; Radiodiagnosis; Central nervous system; Nutrition disorder; Nuclear magnetic resonance imaging; Insulin; Encephalon; Body mass index; fMRI; Sensitivity; independent component analysis (ICA); Reward; Nutritional status; Food
• ISSN: 1065-9471; 1097-0193; 1097-0193
• DOI: 10.1002/hbm.21268

Obesity is a key risk factor for the development of insulin resistance, Type 2 diabetes and associated diseases; thus, it has become a major public health concern. In this context, a detailed understanding of brain networks regulating food intake, including hormonal modulation, is crucial. At present, little is known about potential alterations of cerebral networks regulating ingestive behavior. We used “resting state” functional magnetic resonance imaging to investigate the functional connectivity integrity of resting state networks (RSNs) related to food intake in lean and obese subjects using independent component analysis. Our results showed altered functional connectivity strength in obese compared to lean subjects in the default mode network (DMN) and temporal lobe network. In the DMN, obese subjects showed in the precuneus bilaterally increased and in the right anterior cingulate decreased functional connectivity strength. Furthermore, in the temporal lobe network, obese subjects showed decreased functional connectivity strength in the left insular cortex. The functional connectivity magnitude significantly correlated with body mass index (BMI). Two further RSNs, including brain regions associated with food and reward processing, did not show BMI, but insulin associated functional connectivity strength. Here, the left orbitofrontal cortex and right putamen functional connectivity strength was positively correlated with fasting insulin levels and negatively correlated with insulin sensitivity index. Taken together, these results complement and expand previous functional neuroimaging findings by demonstrating that obesity and insulin levels influence brain function during rest in networks supporting reward and food regulation. Hum Brain Mapp, 2011. © 2011 Wiley‐Liss, Inc.