Department of Cognitive Psychology, Institute of Psychology, University of Hamburg, Von-Melle-Park 5, 20146 Hamburg, Germany.
Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Kapittelweg 29, 6525 EN Nijmegen, The Netherlands.
Neuroimage. 2018 Jun;173:176-187. doi: 10.1016/j.neuroimage.2018.02.038. Epub 2018 Feb 21.
Prior knowledge, represented as a schema, facilitates memory encoding. This schema-related learning is assumed to rely on the medial prefrontal cortex (mPFC) that rapidly integrates new information into the schema, whereas schema-incongruent or novel information is encoded by the hippocampus. Stress is a powerful modulator of prefrontal and hippocampal functioning and first studies suggest a stress-induced deficit of schema-related learning. However, the underlying neural mechanism is currently unknown. To investigate the neural basis of a stress-induced schema-related learning impairment, participants first acquired a schema. One day later, they underwent a stress induction or a control procedure before learning schema-related and novel information in the MRI scanner. In line with previous studies, learning schema-related compared to novel information activated the mPFC, angular gyrus, and precuneus. Stress, however, affected the neural ensemble activated during learning. Whereas the control group distinguished between sets of brain regions for related and novel information, stressed individuals engaged the hippocampus even when a relevant schema was present. Additionally, stressed participants displayed aberrant functional connectivity between brain regions involved in schema processing when encoding novel information. The failure to segregate functional connectivity patterns depending on the presence of prior knowledge was linked to impaired performance after stress. Our results show that stress affects the neural ensemble underlying the efficient use of schemas during learning. These findings may have relevant implications for clinical and educational settings.
先前的知识以图式的形式表现出来，有助于记忆编码。这种与图式相关的学习被认为依赖于内侧前额叶皮层（mPFC），它可以快速将新信息整合到图式中，而与图式不一致或新的信息则由海马体编码。压力是调节前额叶和海马体功能的强大因素，最初的研究表明，压力会导致与图式相关的学习能力下降。然而，其潜在的神经机制目前尚不清楚。为了研究压力引起的与图式相关的学习障碍的神经基础，参与者首先学习了一个图式。一天后，他们在磁共振成像扫描仪中学习与图式相关和新的信息之前，经历了压力诱导或对照程序。与之前的研究一致，与新信息相比，学习与图式相关的信息会激活 mPFC、角回和楔前叶。然而，压力会影响学习过程中激活的神经集合。虽然对照组可以区分与图式相关和新的信息的脑区集合，但压力组即使存在相关的图式，也会激活海马体。此外，在编码新信息时，压力组的参与者在与图式处理相关的脑区之间显示出异常的功能连接。根据先前知识的存在来区分功能连接模式的失败与压力后的表现受损有关。我们的研究结果表明，压力会影响学习过程中有效利用图式的神经集合。这些发现可能对临床和教育环境具有重要意义。
