Reactivating Specific Memories During Sleep in Conjunction with a Suppression Context

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

Interventions

BEHAVIORAL

Targeted memory reactivation (odors)

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).

BEHAVIORAL

Targeted memory reactivation (sounds)

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.

Sponsors & Collaborators

• Northwestern University

  lead OTHER

Study Design

Allocation

NA

Purpose

BASIC_SCIENCE

Masking

NONE

Model

SINGLE_GROUP

Eligibility

Min Age

18 Years

Max Age

35 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2022-02-10

Primary Completion

2024-05-30

Completion

2024-05-30

Countries

• United States

Study Locations