title: Brain reward system's alterations in response to food and monetary stimuli in overweight and obese individuals.
abstract: The brain's reward system is crucial to understand obesity in modern society, as increased neural responsivity to reward can fuel the unhealthy food choices that are driving the growing obesity epidemic. Brain's reward system responsivity to food and monetary rewards in individuals with excessive weight (overweight and obese) versus normal weight controls, along with the relationship between this responsivity and body mass index (BMI) were tested. The sample comprised 21 adults with obesity (BMI > 30), 21 with overweight (BMI between 25 and 30), and 39 with normal weight (BMI < 25). Participants underwent a functional magnetic resonance imaging (fMRI) session while performing two tasks that involve the processing of food (Willing to Pay) and monetary rewards (Monetary Incentive Delay). Neural activations within the brain reward system were compared across the three groups. Curve fit analyses were conducted to establish the association between BMI and brain reward system's response. Individuals with obesity had greater food-evoked responsivity in the dorsal and ventral striatum compared with overweight and normal weight groups. There was an inverted U-shape association between BMI and monetary-evoked responsivity in the ventral striatum, medial frontal cortex, and amygdala; that is, individuals with BMIs between 27 and 32 had greater responsivity to monetary stimuli. Obesity is associated with greater food-evoked responsivity in the ventral and dorsal striatum, and overweight is associated with greater monetary-evoked responsivity in the ventral striatum, the amygdala, and the medial frontal cortex. Findings suggest differential reactivity of the brain's reward system to food versus monetary rewards in obesity and overweight. Hum Brain Mapp 38:666-677, 2017. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Institute of Neuroscience F. Olóriz & Mind, Brain, and Behavior Research Center-CIMCYC, Universidad de Granada, Granada, Spain.
authors.forename: Juan
authors.initials: J
authors.lastname: Verdejo-Román
authors.affiliation: Institute of Neuroscience F. Olóriz & Mind, Brain, and Behavior Research Center-CIMCYC, Universidad de Granada, Granada, Spain.|Red de Trastornos Adictivos, Universidad de Granada, Granada, Spain.
authors.forename: Raquel
authors.initials: R
authors.lastname: Vilar-López
authors.affiliation: Institute of Neuroscience F. Olóriz & Mind, Brain, and Behavior Research Center-CIMCYC, Universidad de Granada, Granada, Spain.
authors.forename: Juan F
authors.initials: JF
authors.lastname: Navas
authors.affiliation: Department of Psychiatry, Bellvitge University Hospital-IDIBELL, Hospitalet de Llobregat, Barcelona, Spain.|CIBERSAM, Carlos III Health Institute, Madrid, Spain.|Department of Psychobiology and Methodology in Health Sciences, Universitat Autònoma de Barcelona, Barcelona, Spain.
authors.forename: Carles
authors.initials: C
authors.lastname: Soriano-Mas
authors.affiliation: School of Psychological Sciences & Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Australia.
authors.forename: Antonio
authors.initials: A
authors.lastname: Verdejo-García
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001066:Appetite; D015992:Body Mass Index; D001921:Brain / Q000000981:diagnostic imaging / Q000503:physiopathology*; D005246:Feedback; D005260:Female; D005502:Food; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000473:pathology / Q000503:physiopathology / Q000523:psychology; D050177:Overweight / Q000473:pathology / Q000503:physiopathology / Q000523:psychology; D012201:Reward; D064232:Visual Analog Scale
keywords: fMRI; food; monetary; obesity; overweight; reward