An interventional study of Congruent vs. Incongruent and Immediate vs. Awake vs. Asleep in Memory Consolidation, sponsored by University of Pennsylvania. Completed at 1 site in United States. Open to participants aged 18 Years to 35 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2025-07-14.
Sponsored by University of Pennsylvania · Not applicable, Interventional, and Basic science
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.
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Exclusion Criteria:
Participants will learn and be tested on two different semantic categories with the same structure that dictates the co-occurrence of different features.
Behavioral: Congruent vs. Incongruent · Behavioral: Immediate vs. Awake vs. Asleep
Participants will learn and be tested on two different semantic categories with different structures that dictate the co-occurrence of different features.
Behavioral: Congruent vs. Incongruent · Behavioral: Immediate vs. Awake vs. Asleep
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.
Behavioral: Congruent vs. Incongruent · Behavioral: Immediate vs. Awake vs. Asleep
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.
Behavioral: Congruent vs. Incongruent · Behavioral: Immediate vs. Awake vs. Asleep
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.
Behavioral: Congruent vs. Incongruent · Behavioral: Immediate vs. Awake vs. Asleep · Behavioral: Targeted memory reactivation (TMR)
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.
Behavioral: Congruent vs. Incongruent · Behavioral: Immediate vs. Awake vs. Asleep · Behavioral: Targeted memory reactivation (TMR)
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.
Behavioral: Congruent vs. Incongruent · Behavioral: Immediate vs. Awake vs. Asleep · Behavioral: Targeted memory reactivation (TMR)
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, 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.
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
| Milestone | Aim 1 Immediate Incongruent | Aim 1 Immediate Congruent | Aim 2 Awake Incongruent | Aim 2 Awake Congruent | Aim 2 Sleep Incongruent | Aim 2 Sleep Congruent |
|---|---|---|---|---|---|---|
| Started | 47 | 47 | 26 | 25 | 22 | 27 |
| Completed | 47 | 47 | 26 | 25 | 22 | 27 |
| Not completed | 0 | 0 | 0 | 0 | 0 | 0 |
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.
| Proportion of correct responses | Aim 1 Immediate Incongruent | Aim 1 Immediate Congruent | Aim 2 Awake Incongruent | Aim 2 Awake Congruent | Aim 2 Sleep Incongruent | Aim 2 Sleep Congruent |
|---|---|---|---|---|---|---|
| Structure Knowledge for a New Modular Category in Stage 2 | 0.563 ± .0983 | .5726 ± .0857 | .6303 ± .0942 | .6266 ± .1043 | .6287 ± .1147 | 0.6231 ± 0.0998 |
Collected over One day (specifically the hours during which participants were completing tasks). Non-serious events are listed at a 0% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| Immediate Congruent | 0/47 (0%) | 0/47 (0%) | 0/47 (0%) |
| Immediate Incongruent | 0/47 (0%) | 0/47 (0%) | 0/47 (0%) |
| Awake Incongruent | 0/26 (0%) | 0/26 (0%) | 0/26 (0%) |
| Awake Congruent | 0/25 (0%) | 0/25 (0%) | 0/25 (0%) |
| Sleep Incongruent | 0/22 (0%) | 0/22 (0%) | 0/22 (0%) |
| Sleep Congruent (SWS) | 0/27 (0%) | 0/27 (0%) | 0/27 (0%) |
| Sleep Congruent (REM) | — | — | — |
Since only a small percentage of participants enter REM sleep within the 2-hour nap opportunity, if we were to randomly assign participants to either non-REM vs. REM conditions, there would be an extremely high likelihood that participants assigned to the REM condition would never enter that sleep phase, rendering that participant's data unusable and resulting in a high attrition rate. In order to generate as much usable data as possible, we therefore decided to remove the REM condition.
| Age, Categorical(Participants) | Immediate Incongruent | Immediate Congruent | Awake Incongruent | Awake Congruent | Sleep Incongruent | Sleep Congruent (SWS) | Sleep Congruent (REM) | Total |
|---|---|---|---|---|---|---|---|---|
| <=18 years | 0 | 0 | 0 | 0 | 0 | 0 | — | 0 |
| Between 18 and 65 years | 47 | 47 | 26 | 25 | 22 | 27 | — | 194 |
| >=65 years | 0 | 0 | 0 | 0 | 0 | 0 | — | 0 |
| Age, Continuous(years) | Immediate Incongruent | Immediate Congruent | Awake Incongruent | Awake Congruent | Sleep Incongruent | Sleep Congruent (SWS) | Sleep Congruent (REM) | Total |
|---|---|---|---|---|---|---|---|---|
| Mean | 25.0213 ± 1.9052 | 25.6809 ± 1.7706 | 21.19 ± 3.9 | 23.08 ± 4.75 | 20.95 ± 3.58 | 22.96 ± 4.42 | — | 23.67 ± 3.69 |
| Sex: Female, Male(Participants) | Immediate Incongruent | Immediate Congruent | Awake Incongruent | Awake Congruent | Sleep Incongruent | Sleep Congruent (SWS) | Sleep Congruent (REM) | Total |
|---|---|---|---|---|---|---|---|---|
| Female | 30 | 29 | 13 | 15 | 16 | 16 | — | 119 |
| Male | 17 | 18 | 13 | 10 | 6 | 11 | — | 75 |
| Ethnicity (NIH/OMB)(Participants) | Immediate Incongruent | Immediate Congruent | Awake Incongruent | Awake Congruent | Sleep Incongruent | Sleep Congruent (SWS) | Sleep Congruent (REM) | Total |
|---|---|---|---|---|---|---|---|---|
| Hispanic or Latino | 5 | 6 | 0 | 6 | 0 | 2 | — | 19 |
| Not Hispanic or Latino | 42 | 41 | 24 | 18 | 22 | 25 | — | 172 |
| Unknown or Not Reported | 0 | 0 | 2 | 1 | 0 | 0 | — | 3 |
| Race (NIH/OMB)(Participants) | Immediate Incongruent | Immediate Congruent | Awake Incongruent | Awake Congruent | Sleep Incongruent | Sleep Congruent (SWS) | Sleep Congruent (REM) | Total |
|---|---|---|---|---|---|---|---|---|
| American Indian or Alaska Native | 1 | 0 | 0 | 2 | 0 | 1 | — | 4 |
| Asian | 4 | 3 | 13 | 9 | 13 | 16 | — | 58 |
| Native Hawaiian or Other Pacific Islander | 0 | 0 | 0 | 0 | 0 | 0 | — | 0 |
| Black or African American | 0 | 2 | 2 | 2 | 3 | 0 | — | 9 |
| White | 42 | 41 | 8 | 9 | 4 | 9 | — | 113 |
| More than one race | 0 | 1 | 1 | 1 | 1 | 1 | — | 5 |
| Unknown or Not Reported | 0 | 0 | 2 | 2 | 1 | 0 | — | 5 |
| Region of Enrollment(participants) | Immediate Incongruent | Immediate Congruent | Awake Incongruent | Awake Congruent | Sleep Incongruent | Sleep Congruent (SWS) | Sleep Congruent (REM) | Total |
|---|---|---|---|---|---|---|---|---|
| United States | 47 | 47 | 26 | 25 | 22 | 27 | — | 194 |
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