Cognitive Neuroscience Program, Department of Psychology, Florida International University, Miami, Florida 33199, USA.
Department of Environmental Health Sciences, Florida International University, Miami, Florida 33199, USA.
Learn Mem. 2021 Mar 15;28(4):134-147. doi: 10.1101/lm.052365.120. Print 2021 Apr.
Remembering sequences of events defines episodic memory, but retrieval can be driven by both ordinality and temporal contexts. Whether these modes of retrieval operate at the same time or not remains unclear. Theoretically, medial prefrontal cortex (mPFC) confers ordinality, while the hippocampus (HC) associates events in gradually changing temporal contexts. Here, we looked for evidence of each with BOLD fMRI in a sequence task that taxes both retrieval modes. To test ordinal modes, items were transferred between sequences but retained their position (e.g., AB). Ordinal modes activated mPFC, but not HC. To test temporal contexts, we examined items that skipped ahead across lag distances (e.g., AB). HC, but not mPFC, tracked temporal contexts. There was a mPFC and HC by retrieval mode interaction. These current results suggest that the mPFC and HC are concurrently engaged in different retrieval modes in support of remembering when an event occurred.
记住事件序列定义了情节记忆，但检索可以同时由顺序和时间上下文驱动。这些检索模式是否同时运行尚不清楚。从理论上讲，内侧前额叶皮层（mPFC）赋予顺序，而海马体（HC）则将事件关联到逐渐变化的时间背景中。在这里，我们在一项需要同时使用两种检索模式的序列任务中使用 BOLD fMRI 寻找每种模式的证据。为了测试顺序模式，项目在序列之间转移但保留其位置（例如 AB）。顺序模式激活了 mPFC，但没有激活 HC。为了测试时间上下文，我们检查了跨越滞后距离提前跳过的项目（例如 AB）。只有 HC 而不是 mPFC 跟踪时间上下文。存在 mPFC 和 HC 与检索模式的交互作用。这些当前的结果表明，mPFC 和 HC 同时参与不同的检索模式，以支持记住事件发生的时间。
