Neseliler Selin, Tannenbaum Beth, Zacchia Maria, Larcher Kevin, Coulter Kirsty, Lamarche Marie, Marliss Errol B, Pruessner Jens, Dagher Alain
Montreal Neurological Institute, McGill University, Montréal, Canada.
Crabtree Nutrition Laboratories, Department of Medicine, McGill University Health Centre Research Institute, McGill University, Montréal, Canada.
Appetite. 2017 Sep 1;116:306-314. doi: 10.1016/j.appet.2017.05.016. Epub 2017 May 6.
Psychosocial stress is associated with an increased intake of palatable foods and weight gain in stress-reactive individuals. Personality traits have been shown to predict stress-reactivity. However, it is not known if personality traits influence brain activity in regions implicated in appetite control during psychosocial stress. The current study assessed whether Gray's Behavioural Inhibition System (BIS) scale, a measure of stress-reactivity, was related to the activity of brain regions implicated in appetite control during a stressful period. Twenty-two undergraduate students participated in a functional magnetic resonance imaging (fMRI) experiment once during a non-exam period and once during final exams in a counter-balanced order. In the scanner, they viewed food and scenery pictures. In the exam compared with the non-exam condition, BIS scores related to increased perceived stress and correlated with increased blood-oxygen-level dependent (BOLD) response to high-calorie food images in regions implicated in food reward and subjective value, such as the ventromedial prefrontal cortex, (vmPFC) and the amygdala. BIS scores negatively related to the functional connectivity between the vmPFC and the dorsolateral prefrontal cortex. The results demonstrate that the BIS trait influences stress reactivity. This is observed both as an increased activity in brain regions implicated in computing the value of food cues and decreased connectivity of these regions to prefrontal regions implicated in self-control. This suggests that the effects of real life stress on appetitive brain function and self-control is modulated by a personality trait. This may help to explain why stressful periods can lead to overeating in vulnerable individuals.
心理社会压力与应激反应性个体对美味食物摄入量的增加及体重增加有关。人格特质已被证明可预测应激反应性。然而，尚不清楚人格特质是否会影响心理社会压力期间与食欲控制相关脑区的大脑活动。本研究评估了作为应激反应性指标的格雷行为抑制系统（BIS）量表是否与压力期与食欲控制相关脑区的活动有关。22名本科生以平衡顺序在非考试期间和期末考试期间各参加了一次功能磁共振成像（fMRI）实验。在扫描仪中，他们观看食物和风景图片。与非考试状态相比，在考试状态下，BIS得分与感知到的压力增加相关，并且与涉及食物奖励和主观价值的脑区（如腹内侧前额叶皮层（vmPFC）和杏仁核）对高热量食物图像的血氧水平依赖（BOLD）反应增加相关。BIS得分与vmPFC和背外侧前额叶皮层之间的功能连接呈负相关。结果表明，BIS特质会影响应激反应性。这既表现为涉及计算食物线索价值的脑区活动增加，也表现为这些区域与涉及自我控制的前额叶区域之间的连接减少。这表明现实生活压力对食欲脑功能和自我控制的影响受人格特质调节。这可能有助于解释为什么压力期会导致易感性个体暴饮暴食。
