Reinstatement of Context During Sleep and Its Subsequent Effect on Memory: an fMRI Study

NCT04702724 | Completed

• 1 other identifier: STU00213443-B
• Study Type: interventional
• Target: 26
• Locations: 1 country
• Sites: 1

Brief Summary

Memory benefits from sleep and these benefits are putatively achieved through reactivation of the neural memory trace during sleep. Studies examining the effects of reactivation commonly focus on single, isolated items - but real-life memories never exist in a vacuum. Individual memories are bound to the context (e.g., the location, time and state of mind in which they are encoded) and this context is later reinstated to recall the details related to the memory. The question of how context participated in the process of sleep reactivation has never been directly examined. This experiment will monitor brain activity during memory encoding, sleep and finally retrieval to investigate the role context plays in sleep-related memory consolidation. Monitoring will be done using functional magnetic resonance imaging (fMRI) and electroencephalographic (EEG) recordings. Participants will go through a series of training trials, in which they will have to learn to associate several small images of items or animals with a larger image of scenes - and also learn the spatial location of these smaller images on the screen. The order of the presented images and the scenes in which they are embedded will remain constant throughout training, creating a solid, consistent temporal context in which item memories will be embedded. After training, participants will receive a 90 minute nap opportunity, during which the sounds associated with specific images will be unobtrusively presented. I expect memory for the spatial location of the cued images to improve. Importantly, I hypothesize that this effect will carry over to other items associated with the same scene (i.e., embedded in the same context) and that the temporal order in which the images were learned will govern this effect. I will use the EEG and fMRI data to estimate, on the basis of neuronal pattern activity, the level of contextual reinstatement and will build on these data, in combination with the behavioral results, to model the level of contextual involvement during sleep. These results could pave the way towards a unified theory of sleep's role in memory consolidation, which would encompass computational models of context and memory as well.

Conditions

Sleep; Consolidation

Outcome Measures

Primary Outcomes (3)

• 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 touched the touchscreen. Measured in pixels on a computer screen.

  Approximately 0.5-1.5 hours before sleep onset and approximately 0.5-1.5 hours after sleep offset within the same experimental session

• Results of neural classifier trained to distinguish between different scenes based on blood-oxygen-level-dependent activity

  For each positioning trial in the pre- and post-sleep tests in the scanner, the classifier will produce a measure of the evidence for each of the different scenes (i.e., contexts) being reinstated.

  Approximately 1.5 hours before sleep onset and approximately 1.5 hours after sleep offset within the same experimental session

• Results of neural classifier trained to distinguish between scenes associated with left/right hand motion based on EEG activity

  For each presentation of sounds during sleep, the classifier will produce a measure of the evidence for right/left hand associated contexts.

  Approximately 0.5 hours before sleep onset and approximately 0.5 hours after sleep offset within the same experimental session

Secondary Outcomes (1)

• Modulation of EEG spectral power following sound/odor presentation

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

Study Arms (1)

Experimental group

EXPERIMENTAL

Behavioral: Targeted memory reactivation (sounds)

Interventions

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 get it, 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 a history of metalworking, an injury with shrapnel or metal slivers, a cardiac pacemaker implantation, a neuro-stimulator implantation, or claustrophobia will be excluded. Participants who are or suspect they may be pregnant will not be excluded.

Sponsors & Collaborators

• Northwestern University: lead

Study Sites (1)

Center for Translational Imaging - Northwestern University

Chicago, Illinois, 60611, United States

Location

MeSH Terms

Interventions

Sound

Intervention Hierarchy (Ancestors)

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: May 10, 2021
• Primary Completion: June 30, 2022
• Study Completion: June 30, 2022
• Last Updated: November 1, 2022

Record last verified: 2022-10

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)