The goal of this clinical trial is to learn if focused ultrasound delivered to the brain influences the effects of the anesthetic medication propofol. It will also learn about the safety and feasibility of using ultrasound and anesthesia together to influence the brain. The main questions it aims to answer are: * Does focused ultrasound delivered to the brain influence the effects or the strength of propofol? * Does propofol anesthesia influence the effects of ultrasound delivered to the brain? Researchers will compare focused ultrasound with sham ultrasound (similar technology but not targeted to a brain region) and administer propofol anesthesia, while measuring signals from the brain and behaviors of participants. Participants will: * Obtain one non-contrast MRI scan of the brain * Receive two separate sessions of ultrasound to the brain (one focused and one sham) * Undergo two separate sessions of propofol anesthesia in a laboratory
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
TRIPLE
Enrollment
10
Active (focused) ultrasound
Sham (unfocused) ultrasound
Intravenous propofol administration
Stanford University
Palo Alto, California, United States
Electroencephalographic power spectral density
Electroencephalographic (EEG) power will be computed using the multitaper spectrogram method applied to frontal, central, and posterior EEG leads and will be reported in the 0.5 Hz (delta) to 40 Hz (gamma) range inclusive of all bands therein (delta, theta, alpha, beta, gamma).
Time frame: 3 hour period concurrent with delivery of propofol anesthesia
Percent responsiveness to commands
Measured via electronically delivered commands and electronically monitored response button
Time frame: 3 hours concurrent with delivery of propofol anesthesia
Reaction time to verbal commands
Measured via electronically delivered verbal commands and electronically monitored response button
Time frame: 3 hours concurrent with delivery of propofol anesthesia
Reaction time in visual psychomotor vigilance test
Delivered via computer screen and button
Time frame: Prior to delivery of propofol anesthesia, directly upon cessation of propofol anesthesia, and 15 minutes following cessation of propofol anesthesia
Number of trials completed in 90-second digit symbol substitution test
Using a standardized protocol for the digit symbol substitution test delivered via computer screen and keyboard for participant responses
Time frame: Prior to delivery of propofol anesthesia, directly upon cessation of propofol anesthesia, and 15 minutes following cessation of propofol anesthesia
Pressure pain threshold
Measured via quantitative algometer testing on the trapezius muscle
Time frame: 15 minutes preceding the start of, and following cessation of, delivery of propofol anesthesia
Electroencephalographic power spectral density
Electroencephalographic (EEG) power will be computed using the multitaper spectrogram method applied to frontal, central, and posterior EEG leads and will be reported in the 0.5 Hz (delta) to 40 Hz (gamma) range inclusive of all bands therein (delta, theta, alpha, beta, gamma).
Time frame: 15 minutes preceding the start of, and following cessation of, delivery of propofol anesthesia
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