Sleep Quality and Amyloid-Beta Kinetics

Inclusion Criteria: * Age 45-65 years * Any sex * Any race/ethnicity * Mini-Mental Status Examination score (MMSE) \>=27 * Sleep efficiency measured by actigraphy to determine good sleeper or poor sleeper Exclusion Criteria: * Cognitive impairment as determined by history of MMSE \< 27 * Inability to speak or understand English * BMI \>35 * Any sleep disorders other than insomnia * history of sleep-disordered breathing * STOP-Bang score \> 3 * History or reported symptoms suggestive of restless legs syndrome, narcolepsy or other sleep disorders * Sleep schedule outside the range of bedtime 8PM-12AM and wake time 4AM-9AM * Contraindication to lumbar catheter (anticoagulants; bleeding disorder; allergy to lidocaine or disinfectant; prior central nervous system or lower back surgery) * Cardiovascular disease requiring medication except for controlled hypertension (PI discretion) * Stroke * Hepatic or renal impairment * Pulmonary disease (PI discretion) * Type 1 diabetes * HIV or AIDS * Neurologic or psychiatric disorder requiring medication (PI discretion) * Alcohol or tobacco use (PI discretion) * Use of sedating medications * Inability to get out of bed independently * Abnormal movement of the non-dominant arm (would affect actigraphy data in unpredictable ways) * Abnormal physical examination * Current pregnancy * History of migraine headaches (PI discretion) * History of drug abuse in the past 6 months * Urinary or fecal incontinence * Difficulty sleeping in an unfamiliar environment (good sleep quality group only) * History or presence of any clinically significant medication condition, behavioral or psychiatric condition (including suicidal ideation), or surgical history based on medical record or patient report that could affect the safety of the subject or interfere with study assessments or in the judgment of the PI is not a good candidate