Brain Maturation and Sleep

Study Overview
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Brief Summary
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In this study, the investigator evaluates whether there are age-specific diurnal changes in markers of cortical plasticity in children, adolescents and adults. The question will be investigated by the quantification of brain metabolites and structural brain volumes using magnet resonance imaging (MRI) and electrophysiological markers using sleep encephalography (sleep EEG). In a second step, it will be tested how these markers of cortical plasticity change depending on a modulation of sleep by applying tones during deep sleep.

Detailed Description
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Given that children and adolescents undergo entirely different maturational processes (children show an increase, adolescents a decrease in synapse density) larger diurnal changes in children are expected compared to adolescents concerning brain metabolites and structural markers. These cortical changes in synapse density are thought to be reflected in electrophysiological markers in the sleep EEG (children show a higher slow wave activity, adolescents a reduced slow wave activity). With the modulation of the deep (slow wave) sleep by playing short, low volume tones, the investigators want to test if there is a causal relationship between slow wave sleep and markers of cortical plasticity.

Official Title
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Exploring Diurnal Changes in Markers of Cortical Plasticity Using Multimodal Imaging in Healthy Children, Adolescents and Adults

Conditions
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Healthy

Intervention / Treatment
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* Other: Playing tones during deep sleep
* Other: sham condition


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male and female subjects 8 to 30 years of age, good general health Status right-handedness, Written informed consent after participants' information Exclusion Criteria: sleep disorders (insomnia, sleep disordered breathing, restless legs syndrome) sleep complaints in general irregular sleep-wake rhythm daytime sleep travelling across a time zone within the last month diseases or lesions of the central nervous system psychiatric diseases learning disability skin allergy or very sensitive skin acute pediatric disease pregnancy drug and medication use and abuse nicotine use high caffeine consumption (>2 servings/day (>160 mg caffeine); including coffee, tea, white and dark chocolate, coca cola, energy drink) Alcohol consumption in children and adolescents under 16 years high alcohol consumption in adults (> 1 standard serving/day (>14 mg Alcohol)) high alcohol consumption in adolescents aged 16 years and above (> 3-4 Standard servings per week)

Ages Eligible for Study
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Minimum Age: 8 Years
Maximum Age: 30 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: playing tones<br>During slow-wave sleep short tones (50ms, 50dB) will be played | Other: Playing tones during deep sleep<br>* Playing tones time locked to slow waves (Duration:50ms, volume: 50dB)<br>|
| Sham Comparator: Playing no tones<br>During slow-wave sleep no tones will be played | Other: sham condition<br>* in the sham condition, no tones will be played<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Diurnal changes in brain metabolites | concentration of brain metabolites measured by MR spectroscopy change from evening to morning | 3 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| electrophysiological markers change in dependance of the diurnal variation of brain metabolites | electrophysiological markers (sleep EEG) change in dependance of the diurnal variation of brain metabolites | 3 years | 
| structural markers change in dependance of the diurnal variation of brain metabolites | structural markers (MR volumes) change in dependance of the diurnal variation of brain metabolites | 3 years |