Prevailing theories of hippocampal function argue that memories are rapidly encoded by non-overlapping memory traces. Concurrently, the hippocampus has been argued to integrate across related experiences, enabling generalization. The cognitive neuroscience of memory has been transformed by the recent proliferation of studies using pattern similarity analyses to investigate the neural substrates of memory in humans, marking an exciting and significant advance in our understanding of population-level neural representations. We provide an overview of hippocampal pattern similarity studies published to date. By considering the effects of stimulus type, time-scale, and hippocampal subregions, we account for both increases and decreases in representational similarity. We argue that hippocampal representations for related memories are not fixed. Instead, the evoked representations are flexibly modulated, depending on whether the current goal is to extract generalities or to reinstate specific experiences. In the first comprehensive review of hippocampal pattern similarity analyses, we provide insight into the mechanisms of memory representation and implications for the interpretation of pattern similarity more generally.

普遍的海马功能理论认为，记忆是由不重叠的记忆轨迹快速编码的。同时，海马被认为可以整合相关经验，从而实现泛化。记忆的认知神经科学已经通过使用模式相似性分析来研究人类记忆的神经底物的最新研究而发生了转变，这标志着我们对人群水平的神经表征的理解有了令人激动的重大进步。我们提供了迄今为止发布的海马模式相似性研究的概述。通过考虑刺激类型，时间尺度和海马亚区的影响，我们考虑了代表性相似性的增加和减少。我们认为相关记忆的海马表征是不固定的。代替，根据当前目标是提取一般性还是恢复特定体验，可以灵活地调整诱发的表示。在对海马模式相似性分析的首次全面综述中，我们提供了对记忆表征机制的理解，并更广泛地解释了模式相似性的含义。