Sleep and Performance

Inclusion Criteria: 1. Physically and psychologically healthy 2. Good habitual sleep between 6 and 10 hours in duration, as assessed by questionnaire and pre-study week sleep/wake diary 3. Regular bedtimes, habitually getting up between 05:00 and 09:00, as assessed by questionnaire and pre-study week sleep/wake diary Exclusion Criteria: * Subjects who have any type of non-MRI compatible bioimplant activated by mechanical, electronic, or magnetic means (e.g., cochlear implants, pacemakers, neurostimulators, biostimulators, electronic infusion pumps, etc.), because such devices may be displaced or malfunction. * Subjects who have any type of ferromagnetic bioimplant that could potentially be displaced. * Subjects who have cerebral aneurysm * Subjects who may have shrapnel imbedded in their bodies (such as from war wounds), metal workers and machinists (potential for metallic fragments in or near the eyes). * Minors (younger than 18 years) * Pregnant women ( Participants of childbearing potential will receive a urine pregnancy test. If the test is positive, the participant will be excluded) * Breastfeeding * Subjects who cannot adhere to the experimental protocols for any reason, or have an inability to communicate with the researcher. * no clinical disorders and/or illnesses, no psychiatric illnesses), as assessed by history and questionnaires * no alcohol during study and no normal excessive alcohol consumption assessed by questionnaire * No history of drug or alcohol abuse in the past year and no history of methamphetamine abuse, as assessed by questionnaires. * Not a dependent smoker or vaper, and not morning dependent on tobacco, nicotine, or cannabis, as assessed by questionnaire. * No history of moderate to severe brain injury, as assessed by questionnaire * No anti-psychotic medication for ADHD/ADD, as assessed by questionnaire * No previous adverse reaction to sleep deprivation, as assessed by questionnaire * Not vision-impaired unless corrected back to normal. * Not hearing impaired unless corrected to normal, as assessed by questionnaire * Not pregnant, as assessed by history and questionnaire * No sleep or circadian disorder, as assessed by questionnaires * No use of melatonin within 1 week of study enrollment * No travel across more than one time zone within one month of entering the study and no crossing times zones during study participation, as assessed by questionnaire. * No shift work within three months of entering the study and no shift work during duration study participation, as assessed by questionnaire. * epilepsy