Effectiveness of Transcranial Magnetic Stimulation of the Default Mode Network to Improve Sleep - Clinical Trial

Inclusion Criteria: * Healthy men and non-pregnant women 18-60 (inclusive) years of age free from contraindicated diseases, medications, devices, and conditions. * Must score in the moderate or higher range on the Insomnia Severity Index (ISI ≥ 15) * Must meet the criteria for DSM-5 insomnia disorder as determined by a clinical interview with a board-certified sleep medicine physician. * Sex ratio will be set to \~50% males; \~50% females * Ethnicity ratio will be set to \~29.5% who identify as a minority; \~70.5% who identify as white Exclusion Criteria: * Presence of any metal implant or medical device that may pose a safety risk for MRI or TMS (permanent hearing aids, cochlear implants, medication infusion devices, brain stimulation devices, permanent retainer, etc.) * Self-reported past or present medical diagnosis of sleep or breathing-related disorders such as sleep apnea other than insomnia (potential confounder); * Confounder of Obstructive Sleep Apnea as measured by WatchPAT device at home * Travel outside the time zone within the one week prior to the physical visit and at any point while active in the study (known to affect sleep); * Regular shiftwork within 6-months prior to enrollment in the study (known to affect sleep); * Self-reported past or present history of any seizures or seizure disorders or other contraindication to neurostimulation, for self or any first-degree relatives (safety concern); * Self-reported current use of certain prescription medications that can either influence seizure threshold, or neuroimaging findings (safety concern and potential confounder); * Self-reported caffeine use in excess of 300 mg (e.g., approximately 8 caffeinated sodas or approximately 3-4 12-oz cups of coffee) per day on average (known to affect sleep; potential confounder); * Self-reported or suspected substance abuse or dependence (safety concern; potential confounder); * (Females only) Positive urine pregnancy result (Urine HCG Test results) (safety concern); * Inability to read and sign the consent form (regulatory/ethical issue) * Self-reported history of repeated, recent, or severe fainting spell or syncope * Prior spinal cord surgeries or any spinal/ventricular derivations * Self-reported negative experience due to neurostimulation before * Deviation from self-reported normal bedtime sleep schedules (bedtime between 9:00 pm and 1:00 am