Investigating Near-Threshold Perception During Ultrasonic Deep Brain Stimulation

This study examines the effects of low-intensity focused ultrasound pulsation (LIFUP) on conscious perception and brain physiology in healthy adults using functional Magnetic resonance imaging (MRI), magnetic resonance spectroscopy, or multimodal glymphatic MRI. Participants are assigned by the study team to one of three arms, each involving up to five visits targeting different prespecified brain regions. Participants perform a visual perception task during imaging, with measurements obtained before, during, and after LIFUP. After completing their initially assigned arm, participants may re-enroll in another arm or for a repeat visit following re-screening and new informed consent.

Randomization applies to the order of procedures within each arm, not to assignment of participants among the three arms. The order in which the five brain regions are targeted will be randomized across participants in all three experimental arms

Inclusion criteria

• Participants must be right-handed, English-speaking, and capable of providing written informed consent.
• Participants must have normal or corrected-to-normal vision while wearing contact lenses,
• Participants must have a body mass index of less than 30
• Participants must not be taking medications for any neurological, psychological, or psychiatric condition.

Exclusion criteria

• Participants will be excluded if they have any contraindication to MRI scanning, including possible pregnancy, current breastfeeding BMI greater than 30, metallic substances or implants in the body, claustrophobia, anxiety that would prevent MRI scanning, Participants with tattoos in the head or neck region will also be excluded, while tattoos in other locations will be evaluated by the investigators to determine whether they pose a safety concern.
• cardiopulmonary disease, or an intracranial structural abnormality identified on T1-weighted MRI.
• Women of childbearing potential will be required to complete a study-funded pregnancy test before participation and must have a negative result.
• vision that is not 20/20 or corrected to 20/20 with contact lenses, a history of significant head injury involving loss of consciousness
• a learning disability or other developmental disorder
• any sensory or motor impairment, activity, condition, or circumstance that, in the judgment of the study coordinator or Principal Investigators, would prevent satisfactory completion of the study protocol.