title: Brain structural correlates of reward sensitivity and impulsivity in adolescents with normal and excess weight.
abstract: BACKGROUND
  Neuroscience evidence suggests that adolescent obesity is linked to brain dysfunctions associated with enhanced reward and somatosensory processing and reduced impulse control during food processing. Comparatively less is known about the role of more stable brain structural measures and their link to personality traits and neuropsychological factors on the presentation of adolescent obesity. Here we aimed to investigate regional brain anatomy in adolescents with excess weight vs. lean controls. We also aimed to contrast the associations between brain structure and personality and cognitive measures in both groups.
  
  
  METHODS
  Fifty-two adolescents (16 with normal weight and 36 with excess weight) were scanned using magnetic resonance imaging and completed the Sensitivity to Punishment and Sensitivity to Reward Questionnaire (SPSRQ), the UPPS-P scale, and the Stroop task. Voxel-based morphometry (VBM) was used to assess possible between-group differences in regional gray matter (GM) and to measure the putative differences in the way reward and punishment sensitivity, impulsivity and inhibitory control relate to regional GM volumes, which were analyzed using both region of interest (ROI) and whole brain analyses. The ROIs included areas involved in reward/somatosensory processing (striatum, somatosensory cortices) and motivation/impulse control (hippocampus, prefrontal cortex).
  
  
  RESULTS
  Excess weight adolescents showed increased GM volume in the right hippocampus. Voxel-wise volumes of the second somatosensory cortex (SII) were correlated with reward sensitivity and positive urgency in lean controls, but this association was missed in excess weight adolescents. Moreover, Stroop performance correlated with dorsolateral prefrontal cortex volumes in controls but not in excess weight adolescents.
  
  
  CONCLUSIONS
  Adolescents with excess weight have structural abnormalities in brain regions associated with somatosensory processing and motivation.
authors.affiliation: Department of Personality, Evaluation and Psychological Treatment, University of Granada, Granada, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Moreno-López
authors.forename: Carles
authors.initials: C
authors.lastname: Soriano-Mas
authors.forename: Elena
authors.initials: E
authors.lastname: Delgado-Rico
authors.forename: Jacqueline S
authors.initials: JS
authors.lastname: Rio-Valle
authors.forename: Antonio
authors.initials: A
authors.lastname: Verdejo-García
mesh_terms: D000293:Adolescent; D001699:Biometry; D001835:Body Weight; D001921:Brain / Q000473:pathology*; D016022:Case-Control Studies; D002648:Child; D003710:Demography; D005260:Female; D006801:Humans; D007175:Impulsive Behavior / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D009483:Neuropsychological Tests; D009765:Obesity / Q000473:pathology*; D011678:Punishment; D012201:Reward; D011795:Surveys and Questionnaires