title: Brain regulation of appetite in twins.
abstract: BACKGROUND
  Neural responses to highly energetic food cues are robust and are suppressed by eating. It is not known if neural responsiveness to food cues is an inherited trait and possibly even one that mediates the genetic influences on body weight that have been previously observed.
  
  
  OBJECTIVE
  We investigated the inherited influence on brain responses to high-calorie visual food cues before and after a meal.
  
  
  METHODS
  With the use of a monozygotic twin study design, 21 healthy monozygotic twin pairs consumed a standardized breakfast and, 3.5 h later, underwent the first of 2 functional MRI (fMRI) scans with the use of visual food cues. After the first fMRI session, twins consumed a standardized meal, which was followed by the second fMRI. Serial ratings of appetite and food appeal were obtained. An ad libitum buffet was used to measure total caloric and macronutrient intakes. Intraclass correlations (ICCs) were used to test for inherited influences by comparing whether intrapair similarity was greater than interpair similarity.
  
  
  RESULTS
  Body mass index was highly correlated within twin pairs (ICC: 0.96; P < 0.0001). ICCs also showed a strong intrapair similarity for the meal-induced change in hunger (ICC: 0.41; P = 0.03), fullness (ICC: 0.39; P = 0.04), and the appeal of fattening food (ICC: 0.57; P < 0.001). Twins ate a similar number of kilocalories at the buffet (ICC: 0.43; P = 0.02). Before the meal, the global brain activation across regions involved in satiety processing was not more similar in twins than in unrelated individuals. However, significant ICCs were present after the meal (ICC: 0.39; P = 0.04) and for the meal-induced change in activation by high-calorie visual food cues (ICC: 0.52; P < 0.01).
  
  
  CONCLUSIONS
  Inherited factors influence both satiety perception and the effect of a meal to alter regional brain responses to images of highly energetic food. This trial was registered at clinicaltrials.gov as NCT02483663.
authors.affiliation: Department of Medicine, General Internal Medicine.
authors.forename: Susan J
authors.initials: SJ
authors.lastname: Melhorn
authors.affiliation: Department of Radiology, Integrated Brain Imaging Center.
authors.forename: Sonya
authors.initials: S
authors.lastname: Mehta
authors.affiliation: Department of Epidemiology, Fred Hutchinson Cancer Research Center, Public Health Sciences Division, Seattle WA; and.
authors.forename: Mario
authors.initials: M
authors.lastname: Kratz
authors.affiliation: Department of Medicine, General Internal Medicine.
authors.forename: Vidhi
authors.initials: V
authors.lastname: Tyagi
authors.affiliation: Department of Epidemiology, Twin Registry.
authors.forename: Mary F
authors.initials: MF
authors.lastname: Webb
authors.affiliation: Department of Epidemiology, Twin Registry.
authors.forename: Carolyn J
authors.initials: CJ
authors.lastname: Noonan
authors.affiliation: Department of Epidemiology, Twin Registry.
authors.forename: Dedra S
authors.initials: DS
authors.lastname: Buchwald
authors.affiliation: Department of Epidemiology, VA Epidemiologic Research and Information Center, Vietnam Era Twin Registry, Seattle, WA.
authors.forename: Jack
authors.initials: J
authors.lastname: Goldberg
authors.affiliation: Department of Radiology, Magnetic Resonance Research Laboratory, and.
authors.forename: Kenneth R
authors.initials: KR
authors.lastname: Maravilla
authors.affiliation: Department of Radiology, Integrated Brain Imaging Center, Department of Neurology, University of Washington, Seattle, WA;
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Grabowski
authors.affiliation: Department of Medicine, General Internal Medicine, ellschur@u.washington.edu.
authors.forename: Ellen A
authors.initials: EA
authors.lastname: Schur
mesh_terms: D000293:Adolescent; D000328:Adult; D001069:Appetite Regulation; D015992:Body Mass Index; D001921:Brain / Q000378:metabolism* / Q000473:pathology; D003463:Cues; D002149:Energy Intake; D005260:Female; D006801:Humans; D062409:Lunch; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D059906:Neuroimaging; D009474:Neurons / Q000378:metabolism* / Q000473:pathology; D009765:Obesity / Q000378:metabolism* / Q000473:pathology; D050177:Overweight / Q000378:metabolism* / Q000473:pathology; D014430:Twins, Monozygotic; D014861:Washington; D055815:Young Adult
keywords: fMRI; food intake; obesity; satiety; visual food cues