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The Impact of Reactivation During Sleep on the Consolidation of Abstract Information in Humans

The Emergence of Abstract Structure Knowledge Across Learning and Sleep

Status
Completed
Phases
NA
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT05746299
Enrollment
194
Registered
2023-02-27
Start date
2023-03-29
Completion date
2024-06-30
Last updated
2025-07-14

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Memory Consolidation

Keywords

memory, sleep, learning

Brief summary

In any given cognitive domain, representations of individual elements are not independent but are organized by means of structured relations. Representations of this underlying structure are powerful, allowing generalization and inference in novel environments. In the semantic domain, structure captures associations between different semantic features or concepts (e.g., green, wings, can fly) and is known to influence the development and deterioration of semantic knowledge. The investigators recently found that humans more easily learn novel categories that contain clusters of reliably co-occurring features, revealing an influence of structure on novel category formation. However, a critical unknown is whether learned representations of structure are closely tied to category-specific elements, or whether such representations become abstract to some extent, transformed away from the experienced features. Further, if abstract structural representations do emerge, prior work provides intriguing hints that these representations may require offline consolidation during awake rest or sleep. The investigators have developed a paradigm in which carefully designed graph structures govern the pattern of feature co-occurrences within individual categories. Here the investigators implement a structure transfer extension of this paradigm in order to determine whether learning one structured category facilitates learning of a second identically structured category defined by a new set of features. This facilitation would provide evidence that structure representations are abstract to some degree. Aim 1 will use these methods to evaluate whether abstract structural representations emerge immediately during learning. Aim 2 will determine whether these representations persist, or emerge, over a delay, and whether sleep-based consolidation in particular is needed. The role of replay of recent experience during sleep will be evaluated using electroencephalography (EEG) paired with closed-loop targeted memory reactivation (TMR), a technique that enables causal influence over the consolidation of recently learned information in humans. This work will inform and constrain theories of semantic learning as well as theories of structure learning and representation more broadly.

Interventions

BEHAVIORALCongruent vs. Incongruent

The Congruent vs. Incongruent intervention relates to the feature-based structure of the novel categories (Modular or non-Modular) and whether there is (Congruent) or is not (Incongruent) a match between what was previously learned and the final target category.

BEHAVIORALImmediate vs. Awake vs. Asleep

Immediate, Awake, and Sleep refer to either no break, 2.5 hours awake, or 2 hours asleep plus a 30-minute post-nap break to account for sleep inertia between learning and target category.

Targeted memory reactivation (TMR) is the systematic presentation of sounds during sleep that were associated with certain stimuli during learning and will be administered either during slow wave sleep (SWS) or rapid eye movement (REM) sleep.

Sponsors

National Institute of Mental Health (NIMH)
CollaboratorNIH
University of Pennsylvania
Lead SponsorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
SINGLE (Subject)

Eligibility

Sex/Gender
ALL
Age
18 Years to 35 Years
Healthy volunteers
Yes

Inclusion criteria

* Ages between 18 and 35

Exclusion criteria

* No medical or neurological illness that would impact experimental performance * Not a member of a vulnerable population

Design outcomes

Primary

MeasureTime frameDescription
Structure Knowledge for a New Modular Category in Stage 2In Aim 1, accuracy is collected in a missing feature task 25 min. into the experiment, taking 25 min. In Aim 2, accuracy is collected in a missing feature task over 25 min in Stage 2Accuracy (0-100%) on the behavioral missing feature task in Stage 2, which requires participants to use their memory from earlier in the experiment to make a guess about how to fill in missing features of the category exemplars.

Countries

United States

Participant flow

Participants by arm

ArmCount
Immediate Incongruent
Participants will learn and be tested on two different semantic categories with different structures that dictate the co-occurrence of different features. Congruent vs. Incongruent: The Congruent vs. Incongruent intervention relates to the feature-based structure of the novel categories (Modular or non-Modular) and whether there is (Congruent) or is not (Incongruent) a match between what was previously learned and the final target category. Immediate vs. Awake vs. Asleep: Immediate, Awake, and Sleep refer to either no break, 2.5 hours awake, or 2 hours asleep plus a 30-minute post-nap break to account for sleep inertia between learning and target category.
47
Immediate Congruent
Participants will learn and be tested on two different semantic categories with the same structure that dictates the co-occurrence of different features. Congruent vs. Incongruent: The Congruent vs. Incongruent intervention relates to the feature-based structure of the novel categories (Modular or non-Modular) and whether there is (Congruent) or is not (Incongruent) a match between what was previously learned and the final target category. Immediate vs. Awake vs. Asleep: Immediate, Awake, and Sleep refer to either no break, 2.5 hours awake, or 2 hours asleep plus a 30-minute post-nap break to account for sleep inertia between learning and target category.
47
Awake Incongruent
Participants will learn two different semantic categories, neither of which has a Modular structure. After a 2.5-hour break, they will learn and be tested on a novel semantic category with a Modular structure. Congruent vs. Incongruent: The Congruent vs. Incongruent intervention relates to the feature-based structure of the novel categories (Modular or non-Modular) and whether there is (Congruent) or is not (Incongruent) a match between what was previously learned and the final target category. Immediate vs. Awake vs. Asleep: Immediate, Awake, and Sleep refer to either no break, 2.5 hours awake, or 2 hours asleep plus a 30-minute post-nap break to account for sleep inertia between learning and target category.
26
Awake Congruent
Participants will learn two different semantic categories, one of which has a Modular structure. After a 2.5-hour break, they will learn and be tested on a novel semantic category with a Modular structure. Congruent vs. Incongruent: The Congruent vs. Incongruent intervention relates to the feature-based structure of the novel categories (Modular or non-Modular) and whether there is (Congruent) or is not (Incongruent) a match between what was previously learned and the final target category. Immediate vs. Awake vs. Asleep: Immediate, Awake, and Sleep refer to either no break, 2.5 hours awake, or 2 hours asleep plus a 30-minute post-nap break to account for sleep inertia between learning and target category.
25
Sleep Incongruent
Participants will learn two different semantic categories, one of which has a Modular structure. After a 2-hour nap opportunity, during which TMR will be used to reactivate the non-Modular category, participants will take a 30-minute break. After the break, they will learn and be tested on a novel semantic category with a Modular structure. Congruent vs. Incongruent: The Congruent vs. Incongruent intervention relates to the feature-based structure of the novel categories (Modular or non-Modular) and whether there is (Congruent) or is not (Incongruent) a match between what was previously learned and the final target category. Immediate vs. Awake vs. Asleep: Immediate, Awake, and Sleep refer to either no break, 2.5 hours awake, or 2 hours asleep plus a 30-minute post-nap break to account for sleep inertia between learning and target category. Targeted memory reactivation (TMR): Targeted memory reactivation (TMR) is the systematic presentation of sounds during sleep that were associated with certain stimuli during learning and will be administered either during slow wave sleep (SWS) or rapid eye movement (REM) sleep.
22
Sleep Congruent (SWS)
Participants will learn two different semantic categories, one of which has a Modular structure. After a 2-hour nap opportunity, during which TMR will be used to reactivate the Modular category during slow wave sleep (SWS), participants will take a 30-minute break. After the break, they will learn and be tested on a novel semantic category with a Modular structure. Congruent vs. Incongruent: The Congruent vs. Incongruent intervention relates to the feature-based structure of the novel categories (Modular or non-Modular) and whether there is (Congruent) or is not (Incongruent) a match between what was previously learned and the final target category. Immediate vs. Awake vs. Asleep: Immediate, Awake, and Sleep refer to either no break, 2.5 hours awake, or 2 hours asleep plus a 30-minute post-nap break to account for sleep inertia between learning and target category. Targeted memory reactivation (TMR): Targeted memory reactivation (TMR) is the systematic presentation of sounds during sleep that were associated with certain stimuli during learning and will be administered either during slow wave sleep (SWS) or rapid eye movement (REM) sleep.
27
Sleep Congruent (REM)
Participants will learn two different semantic categories, one of which has a Modular structure. After a 2-hour nap opportunity, during which TMR will be used to reactivate the Modular category during rapid eye movement (REM) sleep, participants will take a 30-minute break. After the break, they will learn and be tested on a novel semantic category with a Modular structure. Congruent vs. Incongruent: The Congruent vs. Incongruent intervention relates to the feature-based structure of the novel categories (Modular or non-Modular) and whether there is (Congruent) or is not (Incongruent) a match between what was previously learned and the final target category. Immediate vs. Awake vs. Asleep: Immediate, Awake, and Sleep refer to either no break, 2.5 hours awake, or 2 hours asleep plus a 30-minute post-nap break to account for sleep inertia between learning and target category. Targeted memory reactivation (TMR): Targeted memory reactivation (TMR) is the systematic presentation of sounds during sleep that were associated with certain stimuli during learning and will be administered either during slow wave sleep (SWS) or rapid eye movement (REM) sleep.
0
Total194

Baseline characteristics

CharacteristicImmediate CongruentAwake IncongruentImmediate IncongruentAwake CongruentSleep IncongruentSleep Congruent (SWS)Total
Age, Categorical
<=18 years
0 Participants0 Participants0 Participants0 Participants0 Participants0 Participants0 Participants
Age, Categorical
>=65 years
0 Participants0 Participants0 Participants0 Participants0 Participants0 Participants0 Participants
Age, Categorical
Between 18 and 65 years
47 Participants26 Participants47 Participants25 Participants22 Participants27 Participants194 Participants
Age, Continuous25.6809 years
STANDARD_DEVIATION 1.7706
21.19 years
STANDARD_DEVIATION 3.9
25.0213 years
STANDARD_DEVIATION 1.9052
23.08 years
STANDARD_DEVIATION 4.75
20.95 years
STANDARD_DEVIATION 3.58
22.96 years
STANDARD_DEVIATION 4.42
23.67 years
STANDARD_DEVIATION 3.69
Ethnicity (NIH/OMB)
Hispanic or Latino
6 Participants0 Participants5 Participants6 Participants0 Participants2 Participants19 Participants
Ethnicity (NIH/OMB)
Not Hispanic or Latino
41 Participants24 Participants42 Participants18 Participants22 Participants25 Participants172 Participants
Ethnicity (NIH/OMB)
Unknown or Not Reported
0 Participants2 Participants0 Participants1 Participants0 Participants0 Participants3 Participants
Race (NIH/OMB)
American Indian or Alaska Native
0 Participants0 Participants1 Participants2 Participants0 Participants1 Participants4 Participants
Race (NIH/OMB)
Asian
3 Participants13 Participants4 Participants9 Participants13 Participants16 Participants58 Participants
Race (NIH/OMB)
Black or African American
2 Participants2 Participants0 Participants2 Participants3 Participants0 Participants9 Participants
Race (NIH/OMB)
More than one race
1 Participants1 Participants0 Participants1 Participants1 Participants1 Participants5 Participants
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
0 Participants0 Participants0 Participants0 Participants0 Participants0 Participants0 Participants
Race (NIH/OMB)
Unknown or Not Reported
0 Participants2 Participants0 Participants2 Participants1 Participants0 Participants5 Participants
Race (NIH/OMB)
White
41 Participants8 Participants42 Participants9 Participants4 Participants9 Participants113 Participants
Region of Enrollment
United States
47 participants26 participants47 participants25 participants22 participants27 participants194 participants
Sex: Female, Male
Female
29 Participants13 Participants30 Participants15 Participants16 Participants16 Participants119 Participants
Sex: Female, Male
Male
18 Participants13 Participants17 Participants10 Participants6 Participants11 Participants75 Participants

Adverse events

Event typeEG000
affected / at risk
EG001
affected / at risk
EG002
affected / at risk
EG003
affected / at risk
EG004
affected / at risk
EG005
affected / at risk
EG006
affected / at risk
deaths
Total, all-cause mortality
0 / 470 / 470 / 260 / 250 / 220 / 270 / 0
other
Total, other adverse events
0 / 470 / 470 / 260 / 250 / 220 / 270 / 0
serious
Total, serious adverse events
0 / 470 / 470 / 260 / 250 / 220 / 270 / 0

Outcome results

Primary

Structure Knowledge for a New Modular Category in Stage 2

Accuracy (0-100%) on the behavioral missing feature task in Stage 2, which requires participants to use their memory from earlier in the experiment to make a guess about how to fill in missing features of the category exemplars.

Time frame: In Aim 1, accuracy is collected in a missing feature task 25 min. into the experiment, taking 25 min. In Aim 2, accuracy is collected in a missing feature task over 25 min in Stage 2

ArmMeasureValue (MEAN)Dispersion
Aim 1 Immediate IncongruentStructure Knowledge for a New Modular Category in Stage 20.563 Proportion of correct responsesStandard Deviation 0.0983
Aim 1 Immediate CongruentStructure Knowledge for a New Modular Category in Stage 2.5726 Proportion of correct responsesStandard Deviation 0.0857
Aim 2 Awake IncongruentStructure Knowledge for a New Modular Category in Stage 2.6303 Proportion of correct responsesStandard Deviation 0.0942
Aim 2 Awake CongruentStructure Knowledge for a New Modular Category in Stage 2.6266 Proportion of correct responsesStandard Deviation 0.1043
Aim 2 Sleep IncongruentStructure Knowledge for a New Modular Category in Stage 2.6287 Proportion of correct responsesStandard Deviation 0.1147
Aim 2 Sleep CongruentStructure Knowledge for a New Modular Category in Stage 20.6231 Proportion of correct responsesStandard Deviation 0.0998

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026