Laing Patrick A F, Dunsmoor Joseph E
The University of Texas at Austin.
J Cogn Neurosci. 2025 Jan 2;37(1):110-134. doi: 10.1162/jocn_a_02244.
Event boundaries help structure the content of episodic memories by segmenting continuous experiences into discrete events. Event boundaries may also serve to preserve meaningful information within an event, thereby actively separating important memories from interfering representations imposed by past and future events. Here, we tested the hypothesis that event boundaries organize emotional memory based on changing dynamics as events unfold. We developed a novel threat-reversal learning task whereby participants encoded trial-unique exemplars from two semantic categories across three phases: preconditioning, fear acquisition, and reversal. Shock contingencies were established for one category during acquisition (CS+) and then switched to the other during reversal (CS-). Importantly, reversal was either separated by a perceptible event boundary (Experiment 1) or occurred immediately after acquisition, with no perceptible context shift (Experiment 2). In a surprise recognition memory test the next day, memory performance tracked the learning contingencies from encoding in Experiment 1, such that participants selectively recognized more threat-associated CS+ exemplars from before (retroactive) and during acquisition, but this pattern reversed toward CS- exemplars encoded during reversal. By contrast, participants with continuous encoding-without a boundary between conditioning and reversal-exhibited undifferentiated memory for exemplars from both categories encoded before acquisition and after reversal. Further analyses highlight nuanced effects of event boundaries on reversing conditioned fear, updating mnemonic generalization, and emotional biasing of temporal source memory. These findings suggest that event boundaries provide anchor points to organize memory for distinctly meaningful information, thereby adaptively structuring memory based on the content of our experiences.
事件边界通过将连续的经历分割成离散的事件来帮助构建情景记忆的内容。事件边界还可能有助于在一个事件中保留有意义的信息，从而主动将重要的记忆与过去和未来事件所施加的干扰性表征区分开来。在这里，我们测试了这样一个假设，即事件边界根据事件展开时不断变化的动态来组织情绪记忆。我们开发了一种新颖的威胁逆转学习任务，参与者在三个阶段对来自两个语义类别的试验唯一范例进行编码：预处理、恐惧习得和逆转。在习得阶段为一个类别建立电击关联（CS+），然后在逆转阶段切换到另一个类别（CS-）。重要的是，逆转要么被一个可感知的事件边界隔开（实验1），要么在习得后立即发生，没有可感知的情境转换（实验2）。在第二天的意外再认记忆测试中，记忆表现追踪了实验1中编码时的学习关联，即参与者选择性地更多地再认来自习得前（追溯性）和习得期间的与威胁相关的CS+范例，但这种模式在逆转期间编码的CS-范例上发生了逆转。相比之下，在预处理和逆转之间没有边界的连续编码的参与者，对习得前和逆转后编码的两个类别的范例表现出无差别的记忆。进一步的分析突出了事件边界对逆转条件性恐惧、更新记忆泛化以及时间源记忆的情绪偏差的细微影响。这些发现表明，事件边界提供了锚点来组织对明显有意义信息的记忆，从而根据我们的经历内容适应性地构建记忆。
