The purpose of this study is to see if mental functions take place during different levels of anesthesia. The researchers expect to gain a deeper understanding of mental function during different levels of anesthesia, and to evaluate if the use of ultrasonic brain stimulation accelerates return to consciousness.
The decision was made in 2023 to focus on the Central Thalmus arm only for this trial. Participants were only randomized to this arm.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
13
LIFUP will be used to stimulate specific brain regions and assess their causal involvement in the control of conscious state and contents.
Propofol will be administered by intravenous infusion. All anesthesia equipment, supplies, and drugs will be provided by anesthesiologists from the University of Michigan Health System. The researchers will manually control the infusion of propofol to achieve target effect-site concentrations
University of Michigan
Ann Arbor, Michigan, United States
Blood Oxygen Level Dependent (BOLD) Response to Visual Stimuli
BOLD signal was measured by Magnetic Resonance Imaging (MRI) scanning of the brain in response to a visual stimuli. This method reflected changes in oxygenation of blood in the brain during a scene-processing task.
Time frame: Up to 90 minutes
Perceptual Criterion Derived From the Signal Detection Theory (SDT)
SDT was a means of measuring participants' ability to differentiate between information-bearing patterns and random patterns that distract from the information. Perceptual criterion measured a participant's tendency to say "yes" or "no" when the participant was unsure if a signal was present. Perceptual criterion was measured on a scale from -1.0 to 1.0, with a score of 0 indicating no bias towards "yes" or "no". Negative scores meant a bias towards "yes" (more likely to say a signal was present), while positive scores meant a bias towards "no" (more likely to say a signal was absent).
Time frame: Up to 90 minutes
Sensitivity Derived From the Signal Detection Theory (SDT)
SDT was a means of measuring participants' ability to differentiate between information-bearing patterns and random patterns that distract from the information. Sensitivity measured a participant's ability to differentiate between real and scrambled images on a scale from 0.0 to 1.0, with higher scores indicating better accuracy in detecting a signal when it was present and lower scores indicating more missed signals. A score of 1.0 was perfect sensitivity (i.e., never missing a real signal).
Time frame: Up to 90 minutes
Grip Force
Participants' grip force of hand squeezing on a rubber ball in response to instructions was measured.
Time frame: Up to 90 minutes
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