Department of Psychology, School of Educational Science, Guizhou Normal University, Guizhou, PR China; Donders Institute for Brain, Cognition, and Behaviour, Radboud University, Radboud University Medical Center, Nijmegen, The Netherlands.
Donders Institute for Brain, Cognition, and Behaviour, Radboud University, Radboud University Medical Center, Nijmegen, The Netherlands.
Neuroimage. 2018 May 1;171:311-322. doi: 10.1016/j.neuroimage.2018.01.010. Epub 2018 Jan 9.
Stress-related disorders, e.g., anxiety and depression, are characterized by decreased top-down control for distracting information, as well as a memory bias for threatening information. However, it is unclear how acute stress biases mnemonic encoding and leads to prioritized storage of threat-related information even if outside the focus of attention. In the current study, healthy adults (N = 53, all male) were randomly assigned to stress induction using the socially evaluated cold-pressor test (SECPT) or a control condition. Participants performed a task in which they were required to identify a target letter within a string of letters that were either identical to the target and thereby facilitating detection (low distractor load) or mixed with other letters to complicate the search (high load). Either a fearful or neutral face was presented on the background, outside the focus of attention. Twenty-four hours later, participants were asked to perform a surprise recognition memory test for those background faces. Stress induction resulted in increased cortisol and negative subjective mood ratings. Stress did not affect visual search performance, however, participants in the stress group showed stronger memory compared to the control group for fearful faces in the low attentional load condition. Critically, the stress induced memory bias was accompanied by decoupling between amygdala and DLFPC during encoding, which may represent a mechanism for decreased ability to filter task-irrelevant threatening background information. The current study provides a potential neural account for how stress can produce a negative memory bias for threatening information even if presented outside the focus of attention. Despite of an adaptive advantage for survival, such tendencies may ultimately also lead to generalized fear, a possibility requiring additional investigation.
应激相关障碍，例如焦虑和抑郁，其特征是对分散注意力的信息的自上而下控制减弱，以及对威胁信息的记忆偏向。然而，目前尚不清楚急性应激如何影响记忆编码，并导致威胁相关信息的优先存储，即使这些信息不在注意力焦点之外。在当前的研究中，健康成年人（N=53，均为男性）被随机分配到使用社会评价冷加压测试（SECPT）或对照条件下进行应激诱导。参与者执行一项任务，要求他们在一串字母中识别目标字母，这些字母要么与目标相同，从而便于检测（低分心负载），要么与其他字母混合，从而使搜索变得复杂（高负载）。在注意力焦点之外的背景上呈现恐惧或中性面孔。24 小时后，要求参与者对那些背景面孔进行惊喜识别记忆测试。应激诱导导致皮质醇和负面主观情绪评分增加。然而，应激并未影响视觉搜索表现，但是在低注意力负载条件下，应激组的参与者对恐惧面孔的记忆表现明显强于对照组。至关重要的是，应激诱导的记忆偏向伴随着杏仁核和 DLFPC 在编码期间的解耦，这可能代表了一种降低过滤任务无关的威胁性背景信息的能力的机制。本研究提供了一个潜在的神经学解释，说明为什么即使威胁信息出现在注意力焦点之外，应激也会导致对威胁信息产生负面的记忆偏向。尽管这种倾向可能具有生存的适应性优势，但最终也可能导致广泛的恐惧，这需要进一步的研究。
