An Enduring Role for Hippocampal Pattern Completion in Addition to an Emergent Nonhippocampal Contribution to Holistic Episodic Retrieval after a 24 h Delay
(2024) In Journal of Neuroscience 44(18).- Abstract
Episodic memory retrieval is associated with the holistic neocortical reinstatement of all event information, an effect driven by hippocampal pattern completion. However, whether holistic reinstatement occurs, and whether hippocampal pattern completion continues to drive reinstatement, after a period of consolidation is unclear. Theories of systems consolidation predict either a time-variant or time-invariant role of the hippocampus in the holistic retrieval of episodic events. Here, we assessed whether episodic events continue to be reinstated holistically and whether hippocampal pattern completion continues to facilitate holistic reinstatement following a period of consolidation. Female and male human participants learned “events”... (More)
Episodic memory retrieval is associated with the holistic neocortical reinstatement of all event information, an effect driven by hippocampal pattern completion. However, whether holistic reinstatement occurs, and whether hippocampal pattern completion continues to drive reinstatement, after a period of consolidation is unclear. Theories of systems consolidation predict either a time-variant or time-invariant role of the hippocampus in the holistic retrieval of episodic events. Here, we assessed whether episodic events continue to be reinstated holistically and whether hippocampal pattern completion continues to facilitate holistic reinstatement following a period of consolidation. Female and male human participants learned “events” that comprised multiple overlapping pairs of event elements (e.g., person–location, object–location, location–person). Importantly, encoding occurred either immediately before or 24 h before retrieval. Using fMRI during the retrieval of events, we show evidence for holistic reinstatement, as well as a correlation between reinstatement and hippocampal pattern completion, regardless of whether retrieval occurred immediately or 24 h after encoding. Thus, hippocampal pattern completion continues to contribute to holistic reinstatement after a delay. However, our results also revealed that some holistic reinstatement can occur without evidence for a corresponding signature of hippocampal pattern completion after a delay (but not immediately after encoding). We therefore show that hippocampal pattern completion, in addition to a nonhippocampal process, has a role in holistic reinstatement following a period of consolidation. Our results point to a consolidation process where the hippocampus and neocortex may work in an additive, rather than compensatory, manner to support episodic memory retrieval.
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- author
- Joensen, Bárður H. LU ; Ashton, Jennifer E. ; Berens, Sam C. ; Gareth Gaskell, M. and Horner, Aidan J.
- organization
- publishing date
- 2024-05-01
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- episodic memory, fMRI, hippocampus, systems consolidation
- in
- Journal of Neuroscience
- volume
- 44
- issue
- 18
- article number
- e1740232024
- pages
- 12 pages
- publisher
- Society for Neuroscience
- external identifiers
-
- scopus:85192021268
- pmid:38527810
- ISSN
- 0270-6474
- DOI
- 10.1523/JNEUROSCI.1740-23.2024
- language
- English
- LU publication?
- yes
- additional info
- Publisher Copyright: Copyright © 2024 Joensen et al.
- id
- 7f0e2e38-d65b-470d-9997-6eed6db4432a
- date added to LUP
- 2024-05-10 11:57:11
- date last changed
- 2024-12-21 12:10:24
@article{7f0e2e38-d65b-470d-9997-6eed6db4432a,
abstract = {{<p>Episodic memory retrieval is associated with the holistic neocortical reinstatement of all event information, an effect driven by hippocampal pattern completion. However, whether holistic reinstatement occurs, and whether hippocampal pattern completion continues to drive reinstatement, after a period of consolidation is unclear. Theories of systems consolidation predict either a time-variant or time-invariant role of the hippocampus in the holistic retrieval of episodic events. Here, we assessed whether episodic events continue to be reinstated holistically and whether hippocampal pattern completion continues to facilitate holistic reinstatement following a period of consolidation. Female and male human participants learned “events” that comprised multiple overlapping pairs of event elements (e.g., person–location, object–location, location–person). Importantly, encoding occurred either immediately before or 24 h before retrieval. Using fMRI during the retrieval of events, we show evidence for holistic reinstatement, as well as a correlation between reinstatement and hippocampal pattern completion, regardless of whether retrieval occurred immediately or 24 h after encoding. Thus, hippocampal pattern completion continues to contribute to holistic reinstatement after a delay. However, our results also revealed that some holistic reinstatement can occur without evidence for a corresponding signature of hippocampal pattern completion after a delay (but not immediately after encoding). We therefore show that hippocampal pattern completion, in addition to a nonhippocampal process, has a role in holistic reinstatement following a period of consolidation. Our results point to a consolidation process where the hippocampus and neocortex may work in an additive, rather than compensatory, manner to support episodic memory retrieval.</p>}},
author = {{Joensen, Bárður H. and Ashton, Jennifer E. and Berens, Sam C. and Gareth Gaskell, M. and Horner, Aidan J.}},
issn = {{0270-6474}},
keywords = {{episodic memory; fMRI; hippocampus; systems consolidation}},
language = {{eng}},
month = {{05}},
number = {{18}},
publisher = {{Society for Neuroscience}},
series = {{Journal of Neuroscience}},
title = {{An Enduring Role for Hippocampal Pattern Completion in Addition to an Emergent Nonhippocampal Contribution to Holistic Episodic Retrieval after a 24 h Delay}},
url = {{http://dx.doi.org/10.1523/JNEUROSCI.1740-23.2024}},
doi = {{10.1523/JNEUROSCI.1740-23.2024}},
volume = {{44}},
year = {{2024}},
}