Neurobiology of Childhood Obesity: An MRI study
Abstract: Childhood obesity is a serious public health problem that is rapidly increasing. Using an addiction model to examine brain activation in response to food cues in childhood obesity, we predict that cue-induced brain activation differences play a critical role in childhood over-eating behavior and relapse during attempts to limit food intake. We propose to use fMRI to examine the response of obese children to food cues as compared to the response of normal weight children. No neuroimaging studies have been published with findings for otherwise healthy obese children. Preliminary analysis of functional magnetic resonance imaging (fMRI) data from a pilot study conducted by our lab in obese and normal weight children show that obese children, compared with normal weight children, have greater activation in response to food cues in key regions of the brain, including the insular region, the hippocampal gyrus region, and the orbitofrontal cortex. We hypothesize that in contrast to normal weight children, overweight children respond differently to food cues as measured by fMRI, including greater regional brain activation in the fasting state and a blunted response to feeding. Our specific aims are to determine: (1) Does the pattern of regional brain activation differ between obese versus normal weight children when food cues are compared to non- food cues? (2) Does fasting versus fed status differentially alter the response to food cues in obese children? We will use fMRI at 3.0 Tesla to conduct an exploratory study in 20 obese and 20 normal weight healthy children ages 8-12 to examine for differences in regional brain activity associated with obesity. Subjects will be studied after a 4-hour fast and following ingestion of a standardized meal. Brain response to visually displayed food images will be contrasted with response to non-food items across fasted and fed conditions in normal weight and obese children. This study promises to elucidate the neural substrates of the response of obese children to food cues and provide insight to the relevance of an addiction approach to overeating behavior. Such knowledge is essential in development of evidence-based methods for prevention and treatment of childhood obesity. Obesity is a major and increasingly important cause of morbidity and mortality, and exposure to visual images of food may contribute greatly to overeating and obesity. This brain study will improve our understanding of the process by which food cues undergo processing and help in the development of behavioral, psychosocial, and environmental interventions and promotions of healthy choices and behavior.