Characterization of long-term memory formation for experimental, real-life-like stressful events on the behavioral and neural level - from encoding, over early to ling-term consolidation

我们对生活片段的记忆最初是生动和详细的，但其中大多数都被转化为更像阵风甚至是示意性的表征。然而，我们对压力经历的长期记忆似乎特别准确和详细。但对人类创伤记忆的回顾性研究表明，这些记忆只是被认为更详细，而不是客观上更好地记住。巩固理论认为，从细节记忆到gist-like记忆和图式记忆的转换反映在海马轴的沿着移动和皮层记忆提取。目前缺乏足够长时间的人类纵向研究来严格检验这些理论。关于压力事件的长期记忆，唯一的动物研究表明，它们保持更长的细节和海马体依赖性，与人类的回顾性研究相反。因此，第一个资助期的目标是描述中性和压力事件的长期记忆形成，从编码，到行为和神经水平的早期到长期巩固。在92名参与者（46名对照）中，从编码时间到使用行为测量、眼动跟踪、生物识别、睡眠多导描记和功能磁共振成像后的8个月内，对一系列长达2.5小时的标准化现实生活压力和中性事件的记忆进行了跟踪。初步的结果显示了一种向不太详细和更多错误记忆的转变。这沿着向前额叶和颞叶皮质检索的转变，表明系统整合显然已经开始。压力事件的记忆形成显示了假设的特殊性，首先是编码过程中的注意力缩小，随后的夜晚延长的慢波睡眠-与早期巩固有关，第二天回忆时杏仁核活动更大，8个月后楔前叶参与更强。第二天，压力大的参与者回忆起更多的核心和内省的细节。即使在8个月后，内省细节的差异仍然存在-与更高的主观细节一致。综上所述，我们的初步结果清楚地表明，记忆的长期巩固和转化已经开始，但同时这些过程尚未完成。这将是目前的巩固理论和理解我们的记忆的复杂特性的压力事件，这些记忆的巩固轨迹的特点，甚至更长的时间将是非常有趣的。因此，拟议项目的目标是建立在这个独特的数据集和后续参与者的记忆长达3年后编码。我们建议不仅在行为和神经水平上表征记忆，而且还探索系统巩固是否可以逆转，以及在多大程度上可以使用文件恢复无法访问的细节。

The memories for the episodes of our lives are initially vivid and detailed but most of them are transformed to more gist-like or even schematic representations. Our long-term memories for stressful experiences however, seem to stay particularly accurate and detailed. But human retrospective studies on traumatic memories suggest that those are only perceived as more detailed but not objectively better remembered. Consolidation theory propose that the transformation from detailed to gist-like and schematic memories is reflected in a shift along the hippocampal axis and to cortical memory retrieval. Longitudinal studies in humans over sufficiently long time periods to rigorously test these theories are currently missing. With respect to long-term memory for stressful events the only animal study suggests that they stay longer detailed and hippocampus dependent, contrary to the retrospective studies in humans. The goal of the first funding period was therefore to characterize long-term memory formation for neutral and stressful episodes, from encoding, over early- to long-term consolidation on the behavioural and neural level. Memory for a 2.5 hours long series of standardized real-life stressful and neutral episodes was tracked in 92 participants (46 controls) from time of encoding and over the 8 months following using behavioural measures, eye-tracking, biometrics, sleep polygraphy, and fMRI. The preliminary results show a transformation to less detailed and more false memories. This goes along with a shift towards prefrontal and temporal cortical retrieval indicating that systems consolidation clearly has begun. Memory formation for stressful episodes shows the hypothesized particularities starting with attentional narrowing during encoding, prolonged slow wave sleep – implicated in early-consolidation – in the subsequent night, greater amygdala activity during recall the next day and stronger precuneal involvement also after 8 months. On the next day, stressed participants recall more central and introspective details. Even after 8 months, the difference in introspective details still exists – consistent with higher subjective detailedness. Taken together, our preliminary results show clearly that long-term consolidation and transformation of the memories have begun but at the same time that these processes are not yet completed. It would be of great interest for current consolidation theories and for the understanding of the complex characteristics of our memories for stressful events to characterize the consolidation trajectories of these memories for an even longer time. The goal of the proposed project is therefore to build on this unique data set and follow-up the participants’ memories for up to 3 years after encoding. We propose not only to characterize the memories on the behavioural and neural level but also explore whether systems consolidation can be reversed and to what degree by then inaccessible details can be restored using fil.