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Siefert EM, Uppuluri S, Mu J, Tandoc MC, Antony JW, Schapiro AC. Memory Reactivation during Sleep Does Not Act Holistically on Object Memory. J Neurosci 2024; 44:e0022242024. [PMID: 38604779 PMCID: PMC11170671 DOI: 10.1523/jneurosci.0022-24.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 03/12/2024] [Accepted: 03/20/2024] [Indexed: 04/13/2024] Open
Abstract
Memory reactivation during sleep is thought to facilitate memory consolidation. Most sleep reactivation research has examined how reactivation of specific facts, objects, and associations benefits their overall retention. However, our memories are not unitary, and not all features of a memory persist in tandem over time. Instead, our memories are transformed, with some features strengthened and others weakened. Does sleep reactivation drive memory transformation? We leveraged the Targeted Memory Reactivation technique in an object category learning paradigm to examine this question. Participants (20 female, 14 male) learned three categories of novel objects, where each object had unique, distinguishing features as well as features shared with other members of its category. We used a real-time EEG protocol to cue the reactivation of these objects during sleep at moments optimized to generate reactivation events. We found that reactivation improved memory for distinguishing features while worsening memory for shared features, suggesting a differentiation process. The results indicate that sleep reactivation does not act holistically on object memories, instead supporting a transformation where some features are enhanced over others.
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Affiliation(s)
- Elizabeth M Siefert
- Department of Psychology, University of Pennsylvania, Philadelphia, Pennsylvania 19104
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Sindhuja Uppuluri
- Department of Psychology, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Jianing Mu
- Department of Psychology, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Marlie C Tandoc
- Department of Psychology, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - James W Antony
- Department of Psychology and Child Development, California Polytechnic State University, San Luis Obispo, California 93407
| | - Anna C Schapiro
- Department of Psychology, University of Pennsylvania, Philadelphia, Pennsylvania 19104
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Liu XL, Ranganath C, O'Reilly RC. A complementary learning systems model of how sleep moderates retrieval practice effects. Psychon Bull Rev 2024:10.3758/s13423-024-02489-1. [PMID: 38530592 DOI: 10.3758/s13423-024-02489-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/02/2024] [Indexed: 03/28/2024]
Abstract
While many theories assume that sleep is critical in stabilizing and strengthening memories, our recent behavioral study (Liu & Ranganath, 2021, Psychonomic Bulletin & Review, 28[6], 2035-2044) suggests that sleep does not simply stabilize memories. Instead, it plays a more complex role, integrating information across two temporally distinct learning episodes. In the current study, we simulated the results of Liu and Ranganath (2021) using our biologically plausible computational model, TEACH, developed based on the complementary learning systems (CLS) framework. Our model suggests that when memories are activated during sleep, the reduced influence of temporal context establishes connections across temporally separated events through mutual training between the hippocampus and neocortex. In addition to providing a compelling mechanistic explanation for the selective effect of sleep, this model offers new examples of the diverse ways in which the cortex and hippocampus can interact during learning.
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Affiliation(s)
- Xiaonan L Liu
- Department of Psychology, The Chinese University of Hong Kong, Hong Kong, Hong Kong.
| | - Charan Ranganath
- Department of Psychology, University of California, Davis, CA, USA
- Center for Neuroscience, University of California, Davis, CA, USA
| | - Randall C O'Reilly
- Department of Psychology, University of California, Davis, CA, USA
- Center for Neuroscience, University of California, Davis, CA, USA
- Department of Computer Science, University of California, Davis, CA, USA
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Schechtman E. When memories get complex, sleep comes to their rescue. Proc Natl Acad Sci U S A 2024; 121:e2402178121. [PMID: 38466857 PMCID: PMC10962965 DOI: 10.1073/pnas.2402178121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/13/2024] Open
Affiliation(s)
- Eitan Schechtman
- Department of Neurobiology and Behavior, University of California Irvine, Irvine, CA92697
- Center for Neurobiology of Learning and Memory, University of California Irvine, Irvine, CA92697
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Siefert E, Uppuluri S, Mu. J, Tandoc M, Antony J, Schapiro A. Memory reactivation during sleep does not act holistically on object memory. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.12.14.571683. [PMID: 38168451 PMCID: PMC10760132 DOI: 10.1101/2023.12.14.571683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Memory reactivation during sleep is thought to facilitate memory consolidation. Most sleep reactivation research has examined how reactivation of specific facts, objects, and associations benefits their overall retention. However, our memories are not unitary, and not all features of a memory persist in tandem over time. Instead, our memories are transformed, with some features strengthened and others weakened. Does sleep reactivation drive memory transformation? We leveraged the Targeted Memory Reactivation technique in an object category learning paradigm to examine this question. Participants (20 female, 14 male) learned three categories of novel objects, where each object had unique, distinguishing features as well as features shared with other members of its category. We used a real-time EEG protocol to cue the reactivation of these objects during sleep at moments optimized to generate reactivation events. We found that reactivation improved memory for distinguishing features while worsening memory for shared features, suggesting a differentiation process. The results indicate that sleep reactivation does not act holistically on object memories, instead supporting a transformation process where some features are enhanced over others.
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Affiliation(s)
- E.M. Siefert
- Department of Psychology, University of Pennsylvania, Philadelphia, PA, 19104, USA
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - S. Uppuluri
- Department of Psychology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - J. Mu.
- Department of Psychology and Child Development, California Polytechnic State University, San Luis Obispo, CA, 93407, USA
| | - M.C. Tandoc
- Department of Psychology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | | | - A.C. Schapiro
- Department of Psychology, University of Pennsylvania, Philadelphia, PA, 19104, USA
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Tal A, Schechtman E, Caughran B, Paller KA, Davachi L. The reach of reactivation: Effects of consciously triggered versus unconsciously triggered reactivation of associative memory. Proc Natl Acad Sci U S A 2024; 121:e2313604121. [PMID: 38408248 PMCID: PMC10927514 DOI: 10.1073/pnas.2313604121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 01/31/2024] [Indexed: 02/28/2024] Open
Abstract
Consolidating memories for long-term storage depends on reactivation. Reactivation occurs both consciously, during wakefulness, and unconsciously, during wakefulness and sleep. While considerable work has examined conscious awake and unconscious sleep reactivation, in this study, we directly compare the consequences of conscious and unconscious reactivation during wakefulness. Forty-one participants learned associations consisting of adjective-object-position triads. Objects were clustered into distinct semantic groups (e.g., fruits, vehicles) such that we could examine consequences of reactivation on semantically related memories. After an intensive learning protocol, we systematically reactivated some of the triads by presenting the adjective as a cue. Reactivation was done so that it was consciously experienced for some triads, and only unconsciously processed for others. Memory for spatial positions, the most distal part of the association, was affected by reactivation in a consciousness-dependent and memory-strength-dependent manner. Conscious reactivation resulted in weakening of semantically related memories that were strong initially, resonating with prior findings of retrieval-induced forgetting. Unconscious reactivation, on the other hand, selectively benefited weak reactivated memories, as previously shown for reactivation during sleep. Semantically linked memories were not impaired, but rather were integrated with the reactivated memory. These results taken together demonstrate that conscious and unconscious reactivation have qualitatively different consequences. Results support a consciousness-dependent inhibition account, whereby unconscious reactivation entails less inhibition than conscious reactivation, thus allowing more liberal spread of activation. Findings set the stage for additional exploration into the role of conscious experience in memory storage and structuring.
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Affiliation(s)
- Amir Tal
- Department of Psychology, Columbia University, New York, NY10027
| | - Eitan Schechtman
- Department of Neurobiology and Behavior, University of California, Irvine, CA92697
- Center for Neurobiology of Learning and Memory, University of California, Irvine, CA92697
- Department of Psychology, Northwestern University, Evanston, IL60208
| | - Bruce Caughran
- Department of Psychology, Northwestern University, Evanston, IL60208
| | - Ken A. Paller
- Department of Psychology, Northwestern University, Evanston, IL60208
| | - Lila Davachi
- Department of Psychology, Columbia University, New York, NY10027
- Department of Clinical Research, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY10962
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Antony JW, Schechtman E. Reap while you sleep: Consolidation of memories differs by how they were sown. Hippocampus 2023; 33:922-935. [PMID: 36973868 PMCID: PMC10429120 DOI: 10.1002/hipo.23526] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 02/26/2023] [Accepted: 03/01/2023] [Indexed: 03/29/2023]
Abstract
Newly formed memories are spontaneously reactivated during sleep, leading to their strengthening. This reactivation process can be manipulated by reinstating learning-related stimuli during sleep, a technique termed targeted memory reactivation. Numerous studies have found that delivering cues during sleep improves memory for simple associations, in which one cue reactivates one tested memory. However, real-life memories often live in rich, complex networks of associations. In this review, we will examine recent forays into investigating how targeted sleep reactivation affects memories within complex paradigms, in which one cue can reactivate multiple tested memories. A common theme across studies is that reactivation consequences do not merely depend on whether memories reside in complex arrangements, but on how memories interact with one another during acquisition. We therefore emphasize how intricate study design details that alter the nature of learning and/or participant intentions impact the outcomes of sleep reactivation. In some cases, complex networks of memories interact harmoniously to bring about mutual memory benefits; in other cases, memories interact antagonistically and produce selective impairments in retrieval. Ultimately, although this burgeoning area of research has yet to be systematically explored, results suggest that the fate of reactivated stimuli within complex arrangements depends on how they were learned.
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Affiliation(s)
- James W. Antony
- Department of Psychology and Child Development, California Polytechnic State University, San Luis Obispo, California, USA
| | - Eitan Schechtman
- Department of Neurobiology and Behavior, University of California, Irvine, California, USA
- Center for Neurobiology of Learning and Memory, University of California Irvine, Irvine, California, USA
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Tal A, Schechtman E, Caughran B, Paller KA, Davachi L. The reach of reactivation: Effects of consciously-triggered versus unconsciously-triggered reactivation of associative memory. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.26.546400. [PMID: 37546839 PMCID: PMC10402076 DOI: 10.1101/2023.07.26.546400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Newly formed memories are not passively stored for future retrieval; rather, they are reactivated offline and thereby strengthened and transformed. However, reactivation is not a uniform process: it occurs throughout different states of consciousness, including conscious rehearsal during wakefulness and unconscious processing during both wakefulness and sleep. In this study, we explore the consequences of reactivation during conscious and unconscious awake states. Forty-one participants learned associations consisting of adjective-object-position triads. Objects were clustered into distinct semantic groups (e.g., multiple fruits, vehicles, musical instruments) which allowed us to examine the consequences of reactivation on semantically-related memories. After an extensive learning phase, some triads were reactivated consciously, through cued retrieval, or unconsciously, through subliminal priming. In both conditions, the adjective was used as the cue. Reactivation impacted memory for the most distal association (i.e., the spatial position of associated objects) in a consciousness-dependent and memory-strength-dependent manner. First, conscious reactivation of a triad resulted in a weakening of other semantically related memories, but only those that were initially more accurate (i.e., memories with lower pre-reactivation spatial errors). This is similar to what has been previously demonstrated in studies employing retrieval-induced forgetting designs. Unconscious reactivation, on the other hand, benefited memory selectively for weak cued items. Semantically linked associations were not impaired, but rather integrated with the reactivated memory. Taken together, our results demonstrate that conscious and unconscious reactivation of memories during wakefulness have qualitatively different consequences on memory for distal associations. Effects are memory-strength-dependent, as has been shown for reactivation during sleep. Results support a consciousness-dependent inhibition account, according to which unconscious reactivation involves less inhibitory dynamics than conscious reactivation, thus allowing more liberal spread of activation. Our findings set the stage for additional exploration into the role of consciousness in memory structuring.
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Affiliation(s)
- Amir Tal
- Department of Psychology, Columbia University, New York, NY, 10027, USA
| | - Eitan Schechtman
- Department of Neurobiology and Behavior, University of California Irvine, Irvine, CA, 92697, USA
- Center for Neurobiology of Learning and Memory, University of California Irvine, Irvine, CA, 92697, USA
- Department of Psychology, Northwestern University, Evanston, IL, 60207, USA
| | - Bruce Caughran
- Department of Psychology, Northwestern University, Evanston, IL, 60207, USA
| | - Ken A Paller
- Department of Psychology, Northwestern University, Evanston, IL, 60207, USA
| | - Lila Davachi
- Department of Psychology, Columbia University, New York, NY, 10027, USA
- Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, 10962, USA
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Schechtman E, Heilberg J, Paller KA. Memory consolidation during sleep involves context reinstatement in humans. Cell Rep 2023; 42:112331. [PMID: 37014750 PMCID: PMC10545811 DOI: 10.1016/j.celrep.2023.112331] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 02/07/2023] [Accepted: 03/19/2023] [Indexed: 04/05/2023] Open
Abstract
New memories are not quarantined from each other when first encoded; rather, they are interlinked with memories that were encoded in temporal proximity or that share semantic features. By selectively biasing memory processing during sleep, here we test whether context influences sleep consolidation. Participants first formed 18 idiosyncratic narratives, each linking four objects together. Before sleep, they also memorized an on-screen position for each object. During sleep, 12 object-specific sounds were unobtrusively presented, thereby cuing the corresponding spatial memories and impacting spatial recall as a function of initial memory strength. As hypothesized, we find that recall for non-cued objects contextually linked with cued objects also changed. Post-cue electrophysiological responses suggest that activity in the sigma band supports context reinstatement and predicts context-related memory benefits. Concurrently, context-specific electrophysiological activity patterns emerge during sleep. We conclude that reactivation of individual memories during sleep evokes reinstatement of their context, thereby impacting consolidation of associated knowledge.
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Affiliation(s)
- Eitan Schechtman
- Department of Psychology, Northwestern University, Evanston, IL 60208, USA; Department of Neurobiology and Behavior, University of California at Irvine, Irvine, CA 92697, USA; Center for Neurobiology of Learning and Memory, University of California at Irvine, Irvine, CA 92697, USA.
| | - Julia Heilberg
- Department of Psychology, Northwestern University, Evanston, IL 60208, USA
| | - Ken A Paller
- Department of Psychology, Northwestern University, Evanston, IL 60208, USA
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