Section on Neurobiology of Fear and Anxiety, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA.
Proc Natl Acad Sci U S A. 2013 Mar 5;110(10):4129-33. doi: 10.1073/pnas.1213923110. Epub 2013 Feb 11.
From job interviews to the heat of battle, it is evident that people think and learn differently when stressed. In fact, learning under stress may have long-term consequences; stress facilitates aversive conditioning and associations learned during extreme stress may result in debilitating emotional responses in posttraumatic stress disorder. The mechanisms underpinning such stress-related associations, however, are unknown. Computational neuroscience has successfully characterized several mechanisms critical for associative learning under normative conditions. One such mechanism, the detection of a mismatch between expected and observed outcomes within the ventral striatum (i.e., "prediction errors"), is thought to be a critical precursor to the formation of new stimulus-outcome associations. An untested possibility, therefore, is that stress may affect learning via modulation of this mechanism. Here we combine a translational model of stress with a cognitive neuroimaging paradigm to demonstrate that stress significantly increases ventral striatum aversive (but not appetitive) prediction error signal. This provides a unique account of the propensity to form threat-related associations under stress with direct implications for our understanding of both normal stress and stress-related disorders.
从求职面试到激烈的战斗，很明显，人们在压力下会以不同的方式思考和学习。事实上，在压力下学习可能会产生长期的后果；压力促进了厌恶条件作用，在极端压力下学习到的关联可能导致创伤后应激障碍中衰弱的情绪反应。然而，这种与压力相关的关联的潜在机制尚不清楚。计算神经科学已经成功地描述了几种在正常条件下进行联想学习的关键机制。其中一种机制是在腹侧纹状体中检测到预期和观察到的结果之间的不匹配（即“预测误差”），被认为是形成新的刺激-结果关联的关键前提。因此，一个未经测试的可能性是，压力可能通过对这种机制的调节来影响学习。在这里，我们将压力的转化模型与认知神经影像学范式相结合，证明压力显著增加了腹侧纹状体的厌恶（而不是食欲）预测误差信号。这为在压力下形成与威胁相关的关联的倾向提供了一个独特的解释，对我们理解正常压力和与压力相关的障碍都有直接的影响。
