title: Higher resting-state activity in reward-related brain circuits in obese versus normal-weight females independent of food intake.
abstract: In response to food cues, obese vs normal-weight individuals show greater activation in brain regions involved in the regulation of food intake under both fasted and sated conditions. Putative effects of obesity on task-independent low-frequency blood-oxygenation-level-dependent signals-that is, resting-state brain activity-in the context of food intake are, however, less well studied.
  
  
  
  To compare eyes closed, whole-brain low-frequency BOLD signals between severely obese and normal-weight females, as assessed by functional magnetic resonance imaging (fMRI).
  
  
  
  Fractional amplitude of low-frequency fluctuations were measured in the morning following an overnight fast in 17 obese (age: 39±11 years, body mass index (BMI): 42.3±4.8 kg m-2) and 12 normal-weight females (age: 36±12 years, BMI: 22.7±1.8 kg m-2), both before and 30 min after consumption of a standardized meal (~260 kcal).
  
  
  
  Compared with normal-weight controls, obese females had increased low-frequency activity in clusters located in the putamen, claustrum and insula (P<0.05). This group difference was not altered by food intake. Self-reported hunger dropped and plasma glucose concentrations increased after food intake (P<0.05); however, these changes did not differ between the BMI groups.
  
  
  
  Reward-related brain regions are more active under resting-state conditions in obese than in normal-weight females. This difference was independent of food intake under the experimental settings applied in the current study. Future studies involving males and females, as well as utilizing repeated post-prandial resting-state fMRI scans and various types of meals are needed to further investigate how food intake alters resting-state brain activity in obese humans.
authors.affiliation: Department of Neuroscience, Uppsala University, Uppsala, Sweden.
authors.forename: P S
authors.initials: PS
authors.lastname: Hogenkamp
authors.affiliation: Department of Neuroscience, Uppsala University, Uppsala, Sweden.
authors.forename: W
authors.initials: W
authors.lastname: Zhou
authors.affiliation: Department of Neuroscience, Uppsala University, Uppsala, Sweden.
authors.forename: L S
authors.initials: LS
authors.lastname: Dahlberg
authors.affiliation: Department of Neuroscience, Uppsala University, Uppsala, Sweden.
authors.forename: J
authors.initials: J
authors.lastname: Stark
authors.affiliation: Department of Neuroscience, Uppsala University, Uppsala, Sweden.
authors.forename: A L
authors.initials: AL
authors.lastname: Larsen
authors.affiliation: Department of Neuroscience, Uppsala University, Uppsala, Sweden.
authors.forename: G
authors.initials: G
authors.lastname: Olivo
authors.affiliation: Department of Neuroscience, Uppsala University, Uppsala, Sweden.
authors.forename: L
authors.initials: L
authors.lastname: Wiemerslage
authors.affiliation: Department of Surgical Sciences, Radiology, Uppsala University, Uppsala, Sweden.
authors.forename: E-M
authors.initials: EM
authors.lastname: Larsson
authors.affiliation: Department of Surgical Sciences, Upper Gastrointestinal Surgery, Uppsala University, Uppsala, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Sundbom
authors.affiliation: Department of Neuroscience, Uppsala University, Uppsala, Sweden.
authors.forename: C
authors.initials: C
authors.lastname: Benedict
authors.affiliation: Department of Neuroscience, Uppsala University, Uppsala, Sweden.
authors.forename: H B
authors.initials: HB
authors.lastname: Schiöth
mesh_terms: D000328:Adult; D001835:Body Weight / Q000502:physiology*; D001921:Brain / Q000000981:diagnostic imaging / Q000502:physiology / Q000503:physiopathology*; D016022:Case-Control Studies; D003463:Cues; D004435:Eating / Q000523:psychology; D005071:Evoked Potentials / Q000502:physiology; D005215:Fasting / Q000502:physiology / Q000523:psychology; D005247:Feeding Behavior; D005260:Female; D005502:Food; D006801:Humans; D008279:Magnetic Resonance Imaging; D009765:Obesity / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000523:psychology; D019518:Postprandial Period / Q000502:physiology; D012146:Rest / Q000502:physiology*; D012201:Reward; D012527:Satiation / Q000502:physiology