Functional Magnetic Resonance Imaging Sleep Study With Auditory Stimuli

OBJECTIVE

Electroencephalography is generally considered the gold standard for defining sleep, but, in
fact, sleep is a behavior and is defined by widely accepted behavioral characteristics like
auditory arousal threshold. Electroencephalography merely became a surrogate for the
behavioral definition when, in the first electroencephalographic sleep studies, researchers
discovered a strong correlation between electroencephalographic slow waves and auditory
arousal thresholds. With the advent of functional magnetic resonance imaging, one would
expect the first sleep studies that used this new measure would have been designed to
correlate it with auditory arousal threshold. However, these studies have never been
conducted. This protocol will fill this gap in the literature. We hypothesize that
undiscovered patterns of brain activity or functional connectivity exist during sleep and
that an approach that defines sleep behaviorally will expose these patterns.

STUDY POPULATION

The subject group in this study will be young, healthy individuals with excellent sleep
health. Choosing this subject group will maximize the probability that subjects will sleep
during all-night functional magnetic resonance imaging. Our target number of completers

is 12 for the pilot study and 43 for the main study.

DESIGN

After a one-week home-monitoring period that includes a regular in-to-bed and out-of bed
time, subjects will undergo two all-night functional magnetic resonance imaging sleep studies
separated by a one-week washout period with continued home

monitoring.. The first night will serve as an adaptation night, which is known to reduce the
sleep alterations that accompany sleeping in a laboratory environment. We will measure sleep
depth behaviorally by arousing subjects with auditory stimuli that progressively increase in
intensity. This procedure will be performed approximately eight times per night. The timing
of the arousals will be distributed randomly across the night.

DATA GENERATED

The data generated will be auditory arousal thresholds and the preceding brain activity and
functional connectivity derived from functional magnetic resonance imaging.

- INCLUSION CRITERIA:

1. able to give informed consent;

2. in good general heath;

3. between the ages of 18 and 34 years;

4. able to sleep on your back for several hours (with breaks).

EXCLUSION CRITERIA:

1. have a medical condition like diabetes or uncontrolled hypertension;

2. have a psychiatric or neurologic condition like depression or stroke;

3. have ever had a seizure;

4. have a sleep disorder like insomnia or sleep apnea;

5. work night shifts;

6. have metal in your body such as pacemakers, metal prostheses, or aneurysm clips that
would make MRI scanning unsafe;

7. are pregnant or nursing;

8. drink too much caffeine (6 or more cups of coffee per day or 10 or more cups of
caffeinated soda per day);

9. use too much alcohol (15 or more alcoholic beverages per week for men and 8 or more
alcoholic beverages per week for women);

10. use too much nicotine (nicotine use within 30 minutes of waking);

11. are afraid of enclosed spaces;

12. have known hearing problems;

13. regularly use a prescription or over-the-counter drug to help you sleep or stay awake;

14. are an employee, contractor, or volunteer of the Laboratory of Functional and
Molecular Imaging in the National Institute of Neurological Disorders and Stroke.