Department of Psychiatry, University of California, San Diego, San Diego (Kaye, Wierenga, Bischoff-Grethe, Berner, Ely, Bailer, Paulus); Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York (Berner); Department of Psychiatry and Psychotherapy, Division of General Psychiatry, Medical University of Vienna, Vienna (Bailer); Laureate Institute for Brain Research, Tulsa, Okla. (Paulus); Departments of Neuroscience and Psychiatry, University of Rochester Medical Center, Rochester, New York (Fudge).
Am J Psychiatry. 2020 Jul 1;177(7):601-610. doi: 10.1176/appi.ajp.2019.19030261. Epub 2020 Mar 12.
Anorexia nervosa has the highest mortality rate of any psychiatric condition, yet the pathophysiology of this disorder and its primary symptom, extreme dietary restriction, remains poorly understood. In states of hunger relative to satiety, the rewarding value of food stimuli normally increases to promote eating, yet individuals with anorexia nervosa avoid food despite emaciation. This study's aim was to examine potential neural insensitivity to these effects of hunger in anorexia nervosa.
At two scanning sessions scheduled 24 hours apart, one after a 16-hour fast and one after a standardized meal, 26 women who were in remission from anorexia nervosa (to avoid the confounding effects of malnutrition) and 22 matched control women received tastes of sucrose solution or ionic water while functional MRI data were acquired. Within a network of interest responsible for food valuation and transforming taste signals into motivation to eat, the authors compared groups across conditions on blood-oxygen-level-dependent (BOLD) signal and task-based functional connectivity.
Participants in the two groups had similar BOLD responses to sucrose and water tastants. A group-by-condition interaction in the ventral caudal putamen indicated that hunger had opposite effects on tastant response in the control group and the remitted anorexia nervosa group, with an increase and a decrease, respectively, in BOLD response when hungry. Hunger had a similar opposite effect on insula-to-ventral caudal putamen functional connectivity in the remitted anorexia nervosa group compared with the control group. Exploratory analyses indicated that lower caudate response to tastants when hungry was associated with higher scores on harm avoidance among participants in the remitted anorexia nervosa group.
Reduced recruitment of neural circuitry that translates taste stimulation to motivated eating behavior when hungry may facilitate food avoidance and prolonged periods of extremely restricted food intake in anorexia nervosa.
神经性厌食症的死亡率在所有精神疾病中最高，但其发病机制和主要症状——极度节食仍知之甚少。与饱腹感相比，饥饿状态下食物刺激的奖赏价值通常会增加，以促进进食，但神经性厌食症患者即使消瘦也会避免进食。本研究旨在探讨神经性厌食症患者对这些饥饿效应的潜在神经不敏感。
在两次相隔 24 小时的扫描会议中，一次是在禁食 16 小时后，一次是在标准餐后，26 名从神经性厌食症中康复的女性（为避免营养不良的混杂影响）和 22 名匹配的对照女性在功能磁共振成像数据采集的同时接受蔗糖溶液或离子水的味觉。在负责食物评估和将味觉信号转化为进食动机的网络中，作者比较了两组在条件下的血氧水平依赖（BOLD）信号和基于任务的功能连接。
两组参与者对蔗糖和水味觉刺激的 BOLD 反应相似。在腹侧尾状核的下部存在一个组间条件的相互作用，表明饥饿对对照组和缓解后的神经性厌食症组的味觉反应有相反的影响，饥饿时 BOLD 反应分别增加和减少。与对照组相比，饥饿时对缓解后的神经性厌食症组的岛叶到腹侧尾状核下部的功能连接也有类似的相反影响。探索性分析表明，当饥饿时对味觉刺激的尾状核反应越低，缓解后的神经性厌食症组参与者的回避伤害得分越高。
当饥饿时，将味觉刺激转化为有动机的进食行为的神经回路的募集减少，可能会促进厌食症患者的食物回避和长时间极度限制食物摄入。
