Department of Psychiatry, University of Colorado Denver, The Children's Hospital, Aurora, Colorado; Department of Neuroscience, University of Colorado Denver, Anschutz Medical Campus, Aurora, Colorado.
Department of Psychology, University of Denver, Denver, Colorado.
Biol Psychiatry. 2011 Oct 15;70(8):728-735. doi: 10.1016/j.biopsych.2011.05.011. Epub 2011 Jun 29.
The neurobiology of bulimia nervosa (BN) is poorly understood. Recent animal literature suggests that binge eating is associated with altered brain dopamine (DA) reward function. In this study, we wanted to investigate DA-related brain reward learning in BN.
Ill BN (n = 20, age: mean = 25.2, SD = 5.3 years) and healthy control women (CW) (n = 23, age: mean = 27.2, SD = 6.4 years) underwent functional magnetic resonance brain imaging together with application of a DA-related reward learning paradigm, the temporal difference (TD) model. That task involves association learning between conditioned visual and unconditioned taste stimuli, as well as unexpected violation of those learned associations. Study participants also completed the Sensitivity to Reward and Punishment Questionnaire.
Bulimia nervosa individuals showed reduced brain response compared with CW for unexpected receipt and omission of taste stimuli, as well as reduced brain regression response to the TD computer model generated reward values, in insula, ventral putamen, amygdala, and orbitofrontal cortex. Those results were qualitatively similar in BN individuals who were nondepressed and unmedicated. Binge/purge frequency in BN inversely predicted reduced TD model response. Bulimia nervosa individuals showed significantly higher Sensitivity to Reward and Punishment compared with CW.
This is the first study that relates reduced brain DA responses in BN to the altered learning of associations between arbitrary visual stimuli and taste rewards. This attenuated response is related to frequency of binge/purge episodes in BN. The brain DA neurotransmitter system could be an important treatment target for BN.
神经性贪食症（BN）的神经生物学机制尚不清楚。最近的动物文献表明，暴食与大脑多巴胺（DA）奖赏功能改变有关。在这项研究中，我们希望研究 BN 中与 DA 相关的大脑奖赏学习。
20 名 BN 患者（年龄：均值=25.2，标准差=5.3 岁）和 23 名健康对照女性（CW）（年龄：均值=27.2，标准差=6.4 岁）接受了功能磁共振脑成像，同时应用了与 DA 相关的奖赏学习范式，即时间差（TD）模型。该任务涉及条件视觉和非条件味觉刺激之间的关联学习，以及对这些学习关联的意外违反。研究参与者还完成了奖赏和惩罚敏感性问卷。
与 CW 相比，BN 个体在意外接收和错过味觉刺激时大脑反应降低，并且在岛叶、腹侧纹状体、杏仁核和眶额皮质中对 TD 计算机模型生成的奖赏值的大脑回归反应降低。在未接受药物治疗且未出现抑郁的 BN 个体中，这些结果在性质上是相似的。BN 个体的暴食/清泻频率与 TD 模型反应的降低呈负相关。BN 个体的奖赏和惩罚敏感性明显高于 CW。
这是第一项将 BN 中大脑 DA 反应的降低与任意视觉刺激和味觉奖赏之间关联学习的改变联系起来的研究。这种反应减弱与 BN 中暴食/清泻发作的频率有关。大脑 DA 神经递质系统可能是 BN 的一个重要治疗靶点。
