Reactivating Specific Memories During Sleep in Conjunction with a Suppression Context

NCT04702750 | Completed

• 1 other identifier: STU00213443-C
• Study Type: interventional
• Target: 23
• Locations: 1 country
• Sites: 1

Brief Summary

Forgetting is often perceived as the inability to retain information, but in fact at least some memory deterioration is due to active suppression processes, that are behaviorally adaptive. These active processes are thought to involve new, inhibitory learning, suggesting that sleep may serve to enhance them as it does other forms of learning. If this were the case, sleep may be harnessed to weaken non-adaptive memories in a manner that may be beneficial for healthy and clinical populations suffering from memory-related symptoms of disorders such as post-traumatic stress disorder (PTSD). To test this idea, this suggested nap study will incorporate specific memories in a suppression context during sleep monitored by encephalography (EEG). First, participants will take part in an item-based directed forgetting task, in which they will be exposed to different words, immediately followed by instructions to either remember the preceding word or not. The instructions will be conveyed using two distinct odors. In fact, the purpose of this first part would be to cement the associations of these odors with the instructions. Next, in an unrelated task, participants will learn the spatial locations of images on a screen. These images will be presented along with congruent sounds (e.g., cat - meow). During a subsequent nap, some of these sounds will be unobtrusively presented along with one of the two previously learned odors or along with a novel odor. In a final spatial-location test, memory for the images whose sounds were presented along with the "forget" odor during sleep is expected to be worse than for the images that were not cued. Memory for the locations of the images whose sounds were presented with one of the two other odors during sleep are expected to improve, possibly more so for the sounds presented with the "remember" odor relative to those presented with the novel odor. If successful, these results would be a first step towards interventions that may serve to selectively weaken memory during sleep.

Conditions

Sleep; Consolidation

Outcome Measures

Primary Outcomes (2)

• Change in error rates between pre- and post-sleep for the different conditions

  The correct location of an image is compared with the position in which the participant has placed it. Measured in pixels on a computer screen.

  Approximately 15 minutes before sleep onset and approximately 15 minutes after sleep offset within the same experimental session

• Modulation of EEG spectral power following sound/odor presentation

  Power modulations within the sigma (12-16 Hz), theta (4-8 Hz) and delta (0.5-4 Hz) ranges immediately following sound onset or at the first sniff after odor delivery. Measured across different EEG channels.

  During sleep within the experimental session, assessed up to 1.5 hours

Study Arms (1)

Experimental group

EXPERIMENTAL

Behavioral: Targeted memory reactivation (odors); Behavioral: Targeted memory reactivation (sounds)

Interventions

Targeted memory reactivation (odors) BEHAVIORAL

I will unobtrusively and repeatedly present learning-related odors during sleep using an olfactometer. This method was shown to improve memory in various tasks. The odors will be presented in blocks with short breaks in-between. Odors will be pleasant as to not wake the participant up. The odors will be presented during non-rapid eye movement sleep (sleep stage 2 and slow wave sleep). The odors presented will be non-congruently associated with instructions in a previous learning task. This manipulation is within-subject - all participants will be exposed to all the odors during sleep, but odors will be associated with different instructions for each participant (counterbalanced).

Experimental group

Targeted memory reactivation (sounds) BEHAVIORAL

I will unobtrusively and repeatedly present learning-related sounds during sleep using speakers. This method was shown to improve memory in various tasks. The sounds will be presented several seconds apart and the volume will be so adjusted as not to disturb the participant's sleep. The sounds will be presented during non-rapid eye movement sleep (sleep stage 2 and slow wave sleep). The sounds presented will be congruently related to the images in the previous learning task. This manipulation is within-subject - all participants will be exposed to sounds, but different specific sounds will be presented for each individual participant.

Experimental group

Eligibility Criteria

• Age: 18 Years - 35 Years
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• \---

You may not qualify if:

• Participants with a history of neurological disorders or of sleep disorders will be excluded.
• Participants who do not believe they would be able to fall asleep in the lab will be excluded.
• Participants with severe asthma requiring hospitalization for treatment, history of significant food or non-food allergy, presence of known smell, taste or ear-nose-throat disorder, or a history of sinusitis or allergic rhinitis will be excluded.
• Participants who are certain they breathe through their mouths during sleep and those who snore (and therefore likely breathe through their mouths as well) will be excluded.

Sponsors & Collaborators

• Northwestern University: lead

Study Sites (1)

Cognitive Neuroscience Lab - Northwestern University

Evanston, Illinois, 60208, United States

Location

MeSH Terms

Interventions

Odorants; Sound

Intervention Hierarchy (Ancestors)

Environment; Ecological and Environmental Phenomena; Biological Phenomena; Environment and Public Health; Radiation, Nonionizing; Radiation; Physical Phenomena

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator

Study Record Dates

• First Submitted: January 7, 2021
• First Posted: January 11, 2021
• Study Start: February 10, 2022
• Primary Completion: May 30, 2024
• Study Completion: May 30, 2024
• Last Updated: November 19, 2024

Record last verified: 2023-11

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)