Stawarczyk David, Wahlheim Christopher N, Etzel Joset A, Snyder Abraham Z, Zacks Jeffrey M
Department of Psychological & Brain Sciences, Washington University in St. Louis, St. Louis, MO 63105;
Department of Psychology, Psychology and Neuroscience of Cognition Research Unit, University of Liège, 4000 Liège, Belgium.
Proc Natl Acad Sci U S A. 2020 Nov 24;117(47):29346-29353. doi: 10.1073/pnas.1918063117.
When encountering unexpected event changes, memories of relevant past experiences must be updated to form new representations. Current models of memory updating propose that people must first generate memory-based predictions to detect and register that features of the environment have changed, then encode the new event features and integrate them with relevant memories of past experiences to form configural memory representations. Each of these steps may be impaired in older adults. Using functional MRI, we investigated these mechanisms in healthy young and older adults. In the scanner, participants first watched a movie depicting everyday activities in a day of an actor's life. They next watched a second nearly identical movie in which some scenes ended differently. Crucially, before watching the last part of each activity, the second movie stopped, and participants were asked to mentally replay how the activity previously ended. Three days later, participants were asked to recall the activities. Neural activity pattern reinstatement in medial temporal lobe (MTL) during the replay phase of the second movie was associated with detecting changes and with better memory for the original activity features. Reinstatements in posterior medial cortex (PMC) additionally predicted better memory for changed features. Compared to young adults, older adults showed a reduced ability to detect and remember changes and weaker associations between reinstatement and memory performance. These findings suggest that PMC and MTL contribute to change processing by reinstating previous event features, and that older adults are less able to use reinstatement to update memory for changed features.
当遇到意外的事件变化时，必须更新相关过去经历的记忆以形成新的表征。当前的记忆更新模型提出，人们必须首先生成基于记忆的预测，以检测和记录环境特征已发生变化，然后对新的事件特征进行编码，并将它们与过去经历的相关记忆整合，以形成构型记忆表征。这些步骤中的每一步在老年人中都可能受损。我们使用功能磁共振成像，在健康的年轻人和老年人中研究了这些机制。在扫描仪中，参与者首先观看一部描绘演员一天日常生活活动的电影。接下来，他们观看第二部几乎相同的电影，其中一些场景的结局不同。至关重要的是，在观看每项活动的最后一部分之前，第二部电影停止，参与者被要求在脑海中重放该活动之前的结局。三天后，要求参与者回忆这些活动。在第二部电影的重放阶段，内侧颞叶（MTL）的神经活动模式恢复与检测变化以及对原始活动特征的更好记忆相关。后内侧皮质（PMC）的恢复还预测了对变化特征的更好记忆。与年轻人相比，老年人检测和记忆变化的能力降低，恢复与记忆表现之间的关联也较弱。这些发现表明，PMC和MTL通过恢复先前的事件特征来促进变化处理，并且老年人不太能够利用恢复来更新对变化特征的记忆。
