Funding terminated prior to initiation.

The investigators goal is to target FUS energy to the centromedian nucleus of the thalamus (CMT), the core of arousal, which is inaccessible by traditional non-invasive neuromodulation devices. The CMT is an ideal stimulation target for augmenting alertness, as it is intimately linked with the cortex through the well described thalamocortical circuit to entrain network oscillations.

In this research study, the investigators will utilize a novel wearable device (ATTN201) to test the dose-response effects of FUS stimulation of the centromedian nucleus of the thalamus (CMT) on alertness, cognitive performance, and reaction time, as well as sleep EEG recordings. Unlike existing technologies, the device in this study will use offline MRI guidance, which is not needed during the actual treatment, allowing users for the first time to sleep and comfortably wear the device out of the clinic. This unique offline MRI guidance approach uses the device's precise head registration and brain anatomy to allow for customized and repeatable tFUS delivery to the CMT.

For this study, the investigators will recruit up to 36 healthy subjects for a safety study that will objectively assess brain parenchyma morphology, and neuropsychiatric and neuropsychological function, following tFUS exposure of the CMT. EEG recordings during parametric sweeps will be obtained for observation of changes in brain network activity.

Inclusion Criteria:

• 22 - 55 y.o.
• Endorse good health with no history of mental or physical illness
• Negative urine pregnancy test if female
• Willingness to adhere to the FUS study schedule and assessments
• Able to read consent document and provide informed consent.
• English is a first or primary fluent language.

Exclusion Criteria:

• Any current psychiatric diagnosis or current Clinical Global Impression ratings of psychiatric illness > 1
• Neurodevelopmental disorders, history of CNS disease, concussion, overnight hospitalization, or other neurologic sequela, tumors, seizures, meningitis, encephalitis, or abnormal CT or MRI of the brain
• Any psychotropic medication is taken within 5 half-lives of procedure time
• Any head trauma resulting in loss of consciousness
• Visual impairment (except the use of glasses)
• Inability to complete cognitive testing
• Active participation or plan for enrollment in another evidence-based clinical trial affecting the psychosocial function
• Repeated abuse or dependence upon drugs (excluding nicotine and caffeine) or taking medications including stimulants, modafinil, thyroid medication, or steroids
• Implanted devices/ferrous metal of any kind
• History of seizure or epilepsy, currently taking medications that lower seizure thresholds
• Claustrophobia or other conditions that would prevent the MRI assessment.
• Pregnancy (or suspected/possible pregnancy or plan to become pregnant in the short term).
• Urine Pregnancy Test: If the subject is a woman of childbearing potential and /or a man capable of fathering a child before, during, and/or after participation precautions should be taken. Examples of acceptable methods of birth control for participants involved in the study include birth control pills, patches, IUDs, condoms, sponges, diaphragm with spermicide, or avoiding sexual activity that could cause the subject to become pregnant.
• Inability to adhere to the treatment schedule.
• Inability to fit the wearable device to the user's head.

Double-blind sham-controlled