Acoustic Stimulation During Restricted Sleep After Sleep Deprivation

Inclusion Criteria: * Healthy men and non-pregnant, non-lactating women 18 to 39 years of age (inclusive) * Must demonstrate adequate comprehension of the protocol, by achieving a score of at least 80% correct on a short multiple-choice quiz. Individuals who fail to achieve a passing score on the initial quiz will be given one opportunity to retest after a review of protocol information. Individuals who fail the comprehension assessment for the second time will be disqualified. Exclusion Criteria: * You must have learned English as your first language * You must have a body mass index (BMI) below 30 (this is a mathematical calculation of your height and weight) * You must not have current or a history of sleeping problems (for example, insomnia or sleep apnea), or symptoms that indicate a potential sleep disorder * You must get an average of 6-9 hours of sleep per night and maintain a normal sleep/wake schedule * You must not drink excessive amounts of caffeine, alcohol, or smoke cigarettes regularly * You must not be on certain medications (determined on a case by case basis) * You must test negative for illicit drugs * Women must not be pregnant or nursing * You must not be participating in another ongoing clinical trial * You must have a social security number or tax identification number in order to be paid for screening and participation in the study * You cannot have a history of the following conditions: Cardiovascular disease, a neurologic disorder, pulmonary disease requiring inhaler use, kidney disease or kidney abnormalities, liver disease of liver abnormalities, a history of psychiatric disorder requiring hospitalization or medication within the last two years or for a continuous period of more than 6 months in the last ten years