Eating Disorders Research and Treatment Center, TU Dresden, Faculty of Medicine, Dresden, Germany.
Neuroimaging Center, TU Dresden.
J Am Acad Child Adolesc Psychiatry. 2016 Nov;55(11):972-979. doi: 10.1016/j.jaac.2016.08.005. Epub 2016 Sep 5.
The ability of individuals with anorexia nervosa (AN) to resist hunger and restrict caloric intake is often believed to reflect an unusual amount of self-control. However, the underlying neural substrate is poorly understood, especially in adolescent patients.
Functional magnetic resonance imaging was used during an intertemporal choice task to probe the hemodynamic correlates of a common measurement of self-control-delayed (monetary) reward discounting-in a sample of acutely ill, predominately adolescent female patients with AN (n = 31) and age-matched healthy controls (n = 31).
Delayed discounting rates did not differ between the groups, but decision making was consistently faster in the AN group. Although no group differences in the neural correlates of reward valuation were evident, activation associated with decision making was decreased in the AN group, most notably in the lateral prefrontal and posterior parietal regions implicated in executive control. Follow-up analysis of difficult decisions showed decreased activation in the AN group in a region of the dorsal anterior cingulate cortex.
Decreased activation in frontoparietal regions involved in decision making, but faster and more consistent choice behavior, suggests that the altered efficiency of neural resource allocation might underlie an increased level of self-control in AN. This pattern of neural activation and behavior might reflect an ingrained "habit" to sustain high-level proactive (anticipatory) cognitive control in AN, which in turn might compromise reactive control mechanisms needed to adapt to changing cognitive demands, such as when difficult decisions must be made.
人们普遍认为，厌食症（AN）患者抵抗饥饿和限制热量摄入的能力反映了他们不同寻常的自我控制能力。然而，其潜在的神经基础仍知之甚少，尤其是在青少年患者中。
我们使用功能磁共振成像（fMRI），在跨期选择任务中，探测一种常见的自我控制测量方法（延迟的金钱奖励折扣）的血流动力学相关性，该方法应用于一组急性发作、以青少年女性为主的 AN 患者（n=31）和年龄匹配的健康对照组（n=31）。
两组的延迟折扣率没有差异，但 AN 组的决策速度始终更快。尽管在奖励估值的神经相关性方面没有发现组间差异，但 AN 组的决策相关激活减少，尤其是在与执行控制相关的外侧前额叶和后顶叶区域。对困难决策的后续分析显示，AN 组在背侧前扣带皮层的一个区域中激活减少。
决策相关的额顶叶区域激活减少，但选择行为更快且更一致，这表明在 AN 中，神经资源分配效率的改变可能是自我控制水平提高的基础。这种神经激活和行为模式可能反映了 AN 中持续高水平主动（预期性）认知控制的根深蒂固的“习惯”，这反过来又可能损害了适应不断变化的认知需求（例如，当必须做出困难决策时）所需的反应性控制机制。
