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Memory Consolidation in Pharmacologically Enhanced Naps

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00777829
Recruitment Status : Completed
First Posted : October 22, 2008
Last Update Posted : December 10, 2015
National Institute of Mental Health (NIMH)
Information provided by (Responsible Party):
Lynelle A. Gehrke, University of California, San Diego

Brief Summary:
This study will examine whether various drugs affecting sleep cycles can improve different kinds of memory.

Condition or disease Intervention/treatment Phase
Sleep Drug: Low-dose sodium oxybate Drug: High-dose sodium oxybate Drug: Low-dose zolpidem Drug: High-dose zolpidem Drug: Placebo Not Applicable

Detailed Description:

Research provides evidence for strong, specific connections between sleeping and memory. This research shows that sleeping is necessary for certain types of memories to form, certain sleep stages lead to specific types of learning and memory consolidation, and naps are as effective as night-time sleep in these learning and memory processes. Current evidence also indicates that there are different types of memory and that the different types can operate and develop independently. In this study, three different memory types will be examined: perceptual, motor, and declarative memory. Perceptual memory is measured through the ability to recognize discrete stimuli; motor memory is measured through the ability to perform specific, coordinated tasks; and declarative memory is measured through the ability to recite memorized information. Different stages in the sleep cycle correlate with improvements in each of these memory processes. For instance, improvement of perceptual memory tasks is dependent on rapid eye motion (REM) sleep; motor learning is related to sleep stage 2; and declarative memory consolidation is related to short wave sleep (SWS), which includes sleep stages 3 and 4.

New drugs can target specific sleep stages and increase the amount of time people spend in those stages when they sleep. For example, the new prescription drug zolpidem increases time spent in stage 2 during sleep, and the drug sodium oxybate increases time spent in SWS. Compared to sleep impacted by either zolpidem or sodium oxybate, normal sleep has proportionally more time spent in REM. This study will use medications, or their lack, to manipulate how much time is spent in REM, stage 2, and SWS. The study will then examine whether the percentage of sleep spent in different stages affects the learning processes associated with those stages.

Participation in this study will last 6 weeks. At the outset, participants will undergo a 2-hour screening visit that will include a medical history, a physical examination, routine lab tests, urine tests for drugs and pregnancy, an electrocardiogram, and a clinical interview for mental health. Participants will also be asked to complete a series of questionnaires on subjective sleep quality, sleep quantity, and daytime sleepiness.

Participants will complete five study visits, beginning 1 week from screening and separated by 5 to 10 days to allow drug wash-out and recovery from effects of the previous visit. Each study visit will involve an overnight stay in a sleep lab. Participants will arrive at 8 PM, go to bed at 10 PM, and be awakened at 5 AM. Between 6 and 8 AM, they will undergo three different tests, each corresponding to a different type of learning and memory process: perceptual, motor, or declarative. The test will include recognizing a target image, typing a specific finger sequence on a keyboard, and verbally recalling a list of words. Participants will receive one of the study drugs or placebo at 8:30 AM and then be allowed to take a 90-minute nap between 9 and 11 AM. They will receive a different drug, different dosage, or placebo at each study visit. Between 4 and 6 PM, they will be retested on the previous three tests. While sleeping, participants will be outfitted with sensors monitoring muscle activity, eye movements, brain waves, heart and lung functioning, and-on the first night-breathing.

For the entire duration of the study, participants will wear an actigraph, which is a wristwatch-like device that monitors sleep cycles. Participants will also be required to maintain a regular sleep schedule, going to sleep and waking up in the same 2-hour window each day. They will also report on sleep schedule and caffeine, alcohol, and drug use in a daily sleep diary. Caffeine, alcohol, and drug use will be prohibited starting at noon on the day prior to each study visit.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 30 participants
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary Purpose: Health Services Research
Official Title: Understanding Memory Consolidation by Studying Pharmacologically Enhanced Naps.
Study Start Date : September 2008
Actual Primary Completion Date : September 2015
Actual Study Completion Date : September 2015

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Memory

Arm Intervention/treatment
Experimental: Low-dose sodium oxybate Drug: Low-dose sodium oxybate
Participants will receive one dose of 2.5 g before each nap.

Experimental: High-dose sodium oxybate Drug: High-dose sodium oxybate
Participants will receive one dose of 3 g before each nap.

Experimental: Low-dose zolpidem Drug: Low-dose zolpidem
Participants will receive one dose of 5 mg before each nap.

Experimental: High-dose zolpidem Drug: High-dose zolpidem
Participants will receive one dose of 10 mg before each nap.

Placebo Comparator: Placebo Drug: Placebo
Participants will receive a dose of placebo before each nap.

Primary Outcome Measures :
  1. Pharmacological enhancement of specific sleep parameters in a dose-dependent manner [ Time Frame: Measured at weekly study visits ]

Secondary Outcome Measures :
  1. Correlation of pharmacological interventions with changes in sleep-stage-specific memory tasks [ Time Frame: Measured at weekly study visits ]

Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.

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Ages Eligible for Study:   18 Years to 39 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Speaks English
  • Resides in the general San Diego community
  • Completed at least 12 years of formal education, because education may affect performance on the cognitive task

Exclusion Criteria:

  • No regular sleep-wake schedule, defined as not meeting study criteria or scoring between 31 and 69 on the Horne-Ostberg Morningness-Eveningness Questionnaire
  • Presence of a sleep disorder reported or detected on the questionnaires
  • Personal or immediate family (i.e., first degree relative) history of diagnosed significant psychopathology
  • Personal history of head injury with loss of consciousness for more than 15 minutes or with seizures
  • History of substance dependence
  • Current use of any psychotropic medications
  • Any cardiac, respiratory, or other medical condition that may affect cerebral metabolism
  • Noncorrectable vision and audition impairments

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00777829

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United States, California
UCSD General Clinical Research Center Laboratory for Sleep and Chronobiology (GCRC-LSC)
La Jolla, California, United States, 92093
Sponsors and Collaborators
University of California, San Diego
National Institute of Mental Health (NIMH)
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Principal Investigator: Sara C. Mednick, PhD UCSD
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Responsible Party: Lynelle A. Gehrke, Administrator, University of California, San Diego Identifier: NCT00777829    
Obsolete Identifiers: NCT00773032
Other Study ID Numbers: K01MH080992-01 ( U.S. NIH Grant/Contract )
K01MH080992-01 ( U.S. NIH Grant/Contract )
First Posted: October 22, 2008    Key Record Dates
Last Update Posted: December 10, 2015
Last Verified: December 2015
Keywords provided by Lynelle A. Gehrke, University of California, San Diego:
Visual Learning
Verbal Memory
Motor Learning
Additional relevant MeSH terms:
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Sodium Oxybate
Sleep Aids, Pharmaceutical
Hypnotics and Sedatives
Central Nervous System Depressants
Physiological Effects of Drugs
GABA-A Receptor Agonists
GABA Agonists
GABA Agents
Neurotransmitter Agents
Molecular Mechanisms of Pharmacological Action
Adjuvants, Anesthesia
Anesthetics, Intravenous
Anesthetics, General