Hippocampal conjunctive encoding, storage, and recall: Avoiding a trade‐off
Abstract
The hippocampus and related structures are thought to be capable of 1) representing cortical activity in a way that minimizes overlap of the representations assigned to different cortical patterns (pattern separation); and 2) modifying synaptic connections so that these representations can later be reinstated from partial or noisy versions of the cortical activity pattern that was present at the time of storage (pattern completion). We point out that there is a trade-off between pattern separation and completion and propose that the unique anatomical and physiological properties of the hippocampus might serve to minimize this trade-off. We use analytical methods to determine quantitative estimates of both separation and completion for specified parameterized models of the hippocampus. These estimates are then used to evaluate the role of various properties and of the hippocampus, such as the activity levels seen in different hippocampal regions, synaptic potentiation and depression, the multi-layer connectivity of the system, and the relatively focused and strong mossy fiber projections. This analysis is focused on the feedforward pathways from the entorhinal cortex (EC) to the dentate gyrus (DG) and region CA3. Among our results are the following: 1) Hebbian synaptic modification (LTP) facilitates completion but reduces separation, unless the strengths of synapses from inactive presynaptic units to active postsynaptic units are reduced (LTD). 2) Multiple layers, as in EC to…
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The hippocampus plays a vital role in learning episodic memory by encoding them through a process that separates similar personal experiences and stores them distinctly, thereby minimizing interference between different episodic memory.
“The hippocampus in the brain plays a vital role in learning episodic memory by encoding them through a process that separates similar personal experiences and stores them distinctly, thereby minimizing interference between different episodic memory [77, 78, 79].”
From Human-inspired Perspectives: A Survey on AI Long-term Memory (2024) · cites this paper as [78]
The hippocampus and cortex of the brain are involved in the encoding of memory, with the hippocampus encoding unique episodic information through its pattern separation properties and the cortex encoding more generalized information through its distributed representations.
“The hippocampus and cortex of the brain are involved in the encoding of memory, with the hippocampus encoding unique episodic information through its pattern separation properties and the cortex encoding more generalized information through its distributed representations [77, 78, 96, 79].”
From Human-inspired Perspectives: A Survey on AI Long-term Memory (2024) · cites this paper as [78]
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Self-citation
- Authors
- O'Reilly, R. C., & McClelland, J. L.
- Affiliations
- Carnegie Mellon University (US)
- Corresponding author
- McClelland, James L.
- ORCID
- McClelland, James L.
- Venue
- Hippocampus
- Publisher
- Wiley
- Published
- 1994-12
- Volume
- 4
- Issue
- 6
- Pages
- 661-682
- ISSN
- 1050-9631 (ISSN-L)
- 1098-1063
- OpenAlex
- W2120629471
- Cited by
- 914
- References
- 7
- Citations by year
- 2026: 28 · 2025: 42 · 2024: 49 · 2023: 40 · 2022: 40 · 2021: 50 · 2020: 36 · 2019: 37 · 2018: 31 · 2017: 40 · 2016: 55 · 2015: 47 · 2014: 55 · 2013: 37 · 2012: 29
- FWCI
- 5.10
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- Hippocampus (publishedVersion)
- PubMed (publishedVersion)
- Funders
- National Institute of Mental Health (MH00385, MH-47566, P01MH047566)
- Topics
- Life Sciences › Neuroscience › Cognitive Neuroscience › Memory and Neural Mechanisms
- Life Sciences › Neuroscience › Cognitive Neuroscience › Neural dynamics and brain function
- Life Sciences › Neuroscience › Cellular and Molecular Neuroscience › Neuroscience and Neuropharmacology Research
- Keywords
- pattern separation, pattern completion, entorhinal cortex, dentate gyrus, CA3, mossy fibers, Hebbian synaptic plasticity, long-term potentiation, long-term depression, feedforward pathways, hippocampal anatomy
- MeSH terms
- Algorithms, Animals, Computer Simulation, Hippocampus, Learning, Memory, Models, Neurological, Nerve Fibers, Probability, Mental Recall, Synapses, Neural Networks, Computer, Rats
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