Gastric stimulation in obese subjects activates the hippocampus and other regions involved in brain reward circuitry

Gene Jack Wang, Julia Yang, Nora D. Volkow, Frank Telang, Yeming Ma, Wei Zhu, Christopher T. Wong, Dardo Tomasi, Panayotis K. Thanos, Joanna S. Fowler

Research output: Contribution to journalArticlepeer-review

136 Scopus citations

Abstract

The neurobiological mechanisms underlying overeating in obesity are not understood. Here, we assessed the neurobiological responses to an Implantable Gastric Stimulator (IGS), which induces stomach expansion via electrical stimulation of the vagus nerve to identify the brain circuits responsible for its effects in decreasing food intake. Brain metabolism was measured with positron emission tomography and 2-deoxy-2[18F]fluoro-D-glucose in seven obese subjects who had the IGS implanted for 1-2 years. Brain metabolism was evaluated twice during activation (on) and during deactivation (off) of the IGS. The Three-Factor Eating Questionnaire was obtained to measure the behavioral components of eating (cognitive restraint, uncontrolled eating, and emotional eating). The largest difference was in the right hippocampus, where metabolism was 18% higher (P < 0.01) during the "on" than "off" condition, and these changes were associated with scores on "emotional eating," which was lower during the on than off condition and with "uncontrolled eating," which did not differ between conditions. Metabolism also was significantly higher in right anterior cerebellum, orbitofrontal cortex, and striatum during the on condition. These findings corroborate the role of the vagus nerve in regulating hippocampal activity and the importance of the hippocampus in modulating eating behaviors linked to emotional eating and lack of control. IGS-induced activation of regions previously shown to be involved in drug craving in addicted subjects (orbitofrontal cortex, hippocampus, cerebellum, and striatum) suggests that similar brain circuits underlie the enhanced motivational drive for food and drugs seen in obese and drug-addicted subjects, respectively.

Original languageEnglish
Pages (from-to)15641-15645
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Volume103
Issue number42
DOIs
StatePublished - 17 Oct 2006

Keywords

  • Brain activation
  • Obesity

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