Hasselmo Michael E
Center for Systems Neuroscience, Boston University, Boston, Massachusetts, USA.
Hippocampus. 2025 Jan;35(1):e23676. doi: 10.1002/hipo.23676.
In keeping with the historical focus of this special issue of Hippocampus, this paper reviews the history of my development of the SPEAR model. The SPEAR model proposes that separate phases of encoding and retrieval (SPEAR) allow effective storage of multiple overlapping associative memories in the hippocampal formation and other cortical structures. The separate phases for encoding and retrieval are proposed to occur within different phases of theta rhythm with a cycle time on the order of 125 ms. The same framework applies to the slower transition between encoding and consolidation dynamics regulated by acetylcholine. The review includes description of the experimental data on acetylcholine and theta rhythm that motivated this model, the realization that existing associative memory models require these different dynamics, and the subsequent experimental data supporting these dynamics. The review also includes discussion of my work on the encoding of episodic memories as spatiotemporal trajectories, and some personal description of the episodic memories from my own spatiotemporal trajectory as I worked on this model.
为契合《海马体》这一特刊的历史聚焦点，本文回顾了我开发SPEAR模型的历程。SPEAR模型提出，编码和检索的不同阶段（SPEAR）能够使多个重叠的关联记忆在海马结构和其他皮质结构中得到有效存储。编码和检索的不同阶段被认为发生在θ节律的不同阶段，其循环周期约为125毫秒。同样的框架也适用于由乙酰胆碱调节的编码和巩固动态之间较慢的转换。这篇综述包括对促使该模型产生的关于乙酰胆碱和θ节律的实验数据的描述，认识到现有的关联记忆模型需要这些不同的动态，以及随后支持这些动态的实验数据。该综述还包括对我将情景记忆编码为时空轨迹的工作的讨论，以及在我研究这个模型时，对来自我自己时空轨迹的情景记忆的一些个人描述。
