Differentioal bold response to food cues under stress in women with bulimia nervosa
Collins, Brittany Lynn
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Bulimia Nervosa (BN) is characterized by chronic relapsing binge and purge behavior. Exposure to environmental food cues and subjective feelings of stress are proximal factors that trigger binge eating. Data suggests that both of these proximal factors increase subjective levels of craving, and subsequently consumption of foods high in fat and sugar. The limbic system is responsible for processing reward salience of food, and disruptions in this system can contribute to aberrant eating behavior such as binge eating. Behavioral studies and fMRI data support abnormal responses to food cues in women with BN. The interaction of the limbic system, prefrontal cortex, visual cortex, and hypothalamic-pituitary-adrenalcorital (HPA) axis, which regulates stress, is not fully understood. Disruption within these neural systems may differentially affect behavioral and neurological responses to environmental food cues and exposure to stressors. Extensive evidence supports that women with BN experience more stress than healthy women, and that stress precedes binge eating for women with BN. There is currently a gap in fMRI and eating disorder literature explaining the neural systems implicated in food cue processing during acute stress. The purpose of this study was to test the hypothesis that women with BN (compared with healthy controls) have differential limbic, prefrontal, and visual system functioning while processing external food cues in a state of acute stress. Results partially support a priori hypotheses in that women with BN have differential BOLD signal response to food cues under stress relative to healthy controls; however, several regions activated in directions opposite of our original hypotheses, including precuneus, nucleus accumbens, and anterior insula. The current study highlights the need for further examination of neural systems involved in acute stress and appetitive (food) cue processing. Evidence from the current study suggests the default mode network and visual information processing systems may be particularly relevant in food cue processing during acute stress.