The hippocampus and its extended network contribute to encoding and recall of episodic experiences. Drawing from recent anatomical, physiological, and behavioral studies, we propose that hippocampal engrams function as indices to mediate memory recall. We broaden this idea to discuss potential relationships between engrams and hippocampal place cells, as well as the molecular, cellular, physiological, and circuit determinants of engrams that permit flexible routing of information to intra- and extrahippocampal circuits for reinstatement, a feature critical to memory indexing. Incorporating indexing into frameworks of memory function opens new avenues of study and even therapies for hippocampal dysfunction.

海马体及其扩展网络有助于编码和回忆情景体验。根据最近的解剖学、生理学和行为学研究，我们提出海马印迹可作为调解记忆回忆的指标。我们扩大了这个想法，以讨论印迹和海马位置细胞之间的潜在关系，以及印迹的分子、细胞、生理和电路决定因素，这些决定因素允许将信息灵活路由到海马内和海马外电路以恢复，这是一个对记忆至关重要的特征索引。将索引纳入记忆功能框架开辟了新的研究途径，甚至是海马功能障碍的治疗方法。