In retrieval of typical episodic memories, recollection leads to retrieval of context details whereas familiarity is only diagnostic for item memory. Unitization is an encoding strategy that allows context details to be processed as item features and therefore increases the involvement of familiarity-based recognition in retrieval of these context details. Relational encoding is a hippocampally-dependent process that stores items and contexts independently. Our previous study Tu and Diana [1] concluded that mixing unitized and non-unitized context details in the same episode reduced the contribution of familiarity to retrieval of any one detail. In the current study, we modified the paradigm by removing visual cues to the context details and the condition-specific blocking during test. Surprisingly, the behavioral data diverged from our 2016 study and indicated that the two manipulated context details in the modified paradigm were processed independently of one another. Neuroimaging data further revealed anterior hippocampal activation was associated with unitization of source information as compared to relational encoding. We also found the predicted increase in bilateral perirhinal cortex activation and decrease in parahippocampal cortex activation during retrieval of unitized color information when compared to relationally-encoded color information. We did not find that same predicted pattern of differences due to unitization of size information.

在典型情景记忆的检索中，回忆会导致上下文细节的检索，而熟悉度只能诊断项目记忆。单元化是一种编码策略，允许将上下文细节作为项目特征进行处理，因此增加了基于熟悉度的识别在检索这些上下文细节时的参与度。关系编码是一个依赖海马的过程，独立存储项目和上下文。我们之前的研究 Tu 和 Diana [1] 得出的结论是，在同一集中混合统一和非统一的上下文细节会降低熟悉度对检索任何一个细节的贡献。在当前的研究中，我们通过删除上下文细节的视觉线索和测试期间特定条件的阻塞来修改范例。令人惊讶的是，行为数据与我们 2016 年的研究不同，表明修改后的范式中的两个被操纵的上下文细节是彼此独立处理的。神经影像数据进一步揭示，与关系编码相比，前海马激活与源信息的统一化相关。我们还发现，与关系编码的颜色信息相比，在检索统一颜色信息期间，预计双侧鼻周皮层激活会增加，海马旁皮层激活会减少。由于尺寸信息的统一，我们没有发现相同的预测差异模式。