PropofolPhase 2NCT06403852
Investigating Near-Threshold Perception During Anesthetic Sedation
A Phase 2 study testing Functional Magnetic Resonance Imaging (fMRI) with propofol in people with Propofol and Anesthesia, run by University of Michigan at 1 site in United States.
Trial summary
The researchers expect to gain a deeper understanding of mental function during different levels of anesthesia. Propofol is FDA approved for use in patients undergoing an anesthetic for medical treatment but is not approved for use in healthy volunteers. Read more about this study
- Who is it for?
- Ages 18 to 40 yearsHealthy volunteers can take part
- Conditions the study is for
- Propofol, Anesthesia, fMRI
- What is being tested?
- Functional Magnetic Resonance Imaging (fMRI) with propofol
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 40 participants
- Where
- 1 siteUnited States
- Study dates
- 10 May 2024to 2 Nov 2025
- Phase
- Phase 2
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 40 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Healthy study subjects with American Society of Anesthesiologists (ASA)-1 status.
- Right-handed
- Body mass index (BMI) less than 30.
- All subjects will be English speakers.
Who cannot join
- Medical contraindication to magnetic resonance imaging (MRI) scanning; are unable to undergo MRI scanning because of possible pregnancy or currently breastfeeding, BMI>30, metallic substances in the body, claustrophobia, anxiety, or cardiopulmonary disease; or have an intracranial structural abnormality on T1-weighted MRI scans.
- History of allergy to propofol, eggs or egg products, soybean or soybean products, neurological, cardiovascular, or pulmonary illness; significant head injury with loss of consciousness; learning disability or other developmental disorder; sleep apnea or any severe snoring history; gastroesophageal reflux disease (GERD) or heartburn; pancreatitis or a history of pancreatitis, or sensory/motor loss sufficient to interfere with performance of the study.
- Tattoos in the head or neck region will be excluded from study; other tattoos are subject to determination by investigators based on their assessment regarding participant safety. To eliminate aspiration risk subjects will also be excluded if they have had recent food or liquid intake (within 8 hours).
- History of drug use, have a positive drug screen, are unwilling to abstain from alcohol for 24 hours prior to dosing, or have a current history of nicotine use.
- Pregnancy
Trial locations and contacts
1 site in 1 country.
About this study
The researchers expect to gain a deeper understanding of mental function during different levels of anesthesia.
Propofol is FDA approved for use in patients undergoing an anesthetic for medical treatment but is not approved for use in healthy volunteers.
Read the detailed description
The stimulus set will include real and scrambled images, where the scrambled images will be created by phase-shuffling a randomly chosen real image from each category to preserve category specific low-level image features. Because scrambled images do not include an object stimulus, the images are used as "catch trials" to determine the subjects' baseline tendency to give positive responses to a question about the subjects' recognition experience. Each object category will include four unique real images and one scrambled image. Each image will be repeated 10 times (i.e., trials) for each 16-min session. The pre-stimulus interval will vary randomly from trial to trial between 4 and 8 seconds to prevent stimulus timing predictability. The stimuli will be presented in a randomized order to prevent category predictability.
- Conditions
- Propofol, Anesthesia, fMRI
- Being tested
- Functional Magnetic Resonance Imaging (fMRI) with propofol
- Keywords
- Hypnotics and Sedatives, Central Nervous System Depressants, Physiological Effects of Drugs, Anesthetics, Intravenous, Anesthetics, General, Anesthetics, Propofol
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Functional Magnetic Resonance Imaging (fMRI) with propofolCombination product
Three 16-min sessions in wakeful baseline, light sedation, and recovery will be conducted (Fig. 2). Light sedation will be achieved by IV infusion of propofol to achieve effect-site concentrations of 1.0 μg/ml. Infusion rate will be manually controlled. An initial bolus dose (525 µg/kg) and subsequent infusion rate (82 µg/kg/min) for each participant
| Study group | Role | What they receive |
|---|---|---|
| Image recognition task | Experimental | The stimulus set will include real and scrambled images, where the scrambled images will be created by phase-shuffling a randomly chosen real image from each category to preserve category specific low-level image features. Each object category will include four unique real images and one scrambled image. Each image will be repeated 10 times (i.e., trials) for each 16-min session. The pre-stimulus interval will vary randomly from trial to trial between 4 and 8 seconds to prevent stimulus timing predictability. The stimuli will be presented in a randomized order to prevent category predictability. Receives: Combination Product: Functional Magnetic Resonance Imaging (fMRI) with propofol |
What is being measured
The primary outcome is the main question the study is designed to answer.
Blood Oxygen Level Dependent (BOLD) Response to Visual Stimuli
Blood oxygen level-dependent (BOLD) responses during a near-threshold visual recognition task were estimated using AFNI (Analysis of Functional NeuroImages). Response estimates were extracted from the fusiform gyrus region of interest at awake baseline and during light propofol sedation. Voxel time series were normalized to zero mean and unit variance, and response values are reported in arbitrary units (AU), not percent BOLD signal change. Higher AU values indicate a greater estimated stimulus-related BOLD response in this region. The results report baseline and sedation values separately.
Measured: Up to 90 minutes
Secondary outcomes (2)
Perceptual Criterion (c) Derived From the Signal Detection Theory (SDT)
Perceptual criterion (c) is a signal detection theory measure of response bias, calculated separately for each 16-minute session as c = -0.5 × [Z(HR) + Z(FAR)]. HR is the proportion of real-image trials with a 'Yes' recognition response; FAR is the proportion of scrambled-image trials with a 'Yes' response. Z is the inverse standard normal cumulative distribution function. The index has no fixed finite theoretical minimum or maximum (-infinity to +infinity). Positive values indicate a conservative response criterion, negative values indicate a liberal criterion, and zero indicates a neutral criterion. Neither higher nor lower values inherently represent better or worse outcomes. No subscales are combined.
Measured: Up to 90 minutes
Sensitivity (d') Derived From the Signal Detection Theory (SDT)
Perceptual sensitivity (d') is a signal detection theory measure of discrimination between real and scrambled images, calculated separately for each 16-minute session as d' = Z(HR) - Z(FAR). HR is the proportion of real-image trials with a 'Yes' recognition response; FAR is the proportion of scrambled-image trials with a 'Yes' response. Z is the inverse standard normal cumulative distribution function. The signed index has no fixed finite theoretical minimum or maximum (-infinity to +infinity). Zero indicates equal hit and false-alarm rates; positive values indicate a higher hit rate, and negative values indicate the reverse. Higher d' indicates better discrimination in the intended direction. No subscales are combined.
Measured: Up to 90 minutes
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted8 May 2024
- Study start10 May 2024
- Primary completion3 Oct 2025
- Study completion2 Nov 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for PropofolStudies of the same condition, open and under way.
- More trials run by University of MichiganThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 40 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Michigan
- Sponsor type
- University, hospital or other
- Collaborators
- National Institute of General Medical Sciences (NIGMS)
- Responsible party
- Principal investigator, Zirui Huang, University of Michigan
- Investigators
- Zirui Huang, Principal investigator, University of Michigan
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06403852
- Sponsor's protocol ID
- HUM00251768
- Other IDs
- R01GM103894
- Status last verified
- Oct 2026
- First submitted
- 3 May 2024
- Last updated
- 30 Oct 2026
- Results posted
- Yes, on ClinicalTrials.gov
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 30 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Investigating Near-Threshold Perception During Anesthetic Sedation
- ClinicalTrials.gov ID
- NCT06403852
- Acronym / sponsor ID
- HUM00251768
- Conditions
- Propofol, Anesthesia, fMRI
- Keywords
- Hypnotics and Sedatives, Central Nervous System Depressants, Physiological Effects of Drugs, Anesthetics, Intravenous, Anesthetics, General, Anesthetics, Propofol
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 40 participants (actual)
- Lead sponsor
- University of MichiganUniversity, hospital or other
- Collaborators
- National Institute of General Medical Sciences (NIGMS)
- Study start
- 10 May 2024 (actual)
- Primary completion
- 3 Oct 2025 (actual)
- Study completion
- 2 Nov 2025 (actual)
- First posted
- 8 May 2024 (actual)
- Results
- Posted 30 Oct 2026
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The researchers expect to gain a deeper understanding of mental function during different levels of anesthesia.
Propofol is FDA approved for use in patients undergoing an anesthetic for medical treatment but is not approved for use in healthy volunteers.
Detailed description
The stimulus set will include real and scrambled images, where the scrambled images will be created by phase-shuffling a randomly chosen real image from each category to preserve category specific low-level image features. Because scrambled images do not include an object stimulus, the images are used as "catch trials" to determine the subjects' baseline tendency to give positive responses to a question about the subjects' recognition experience. Each object category will include four unique real images and one scrambled image. Each image will be repeated 10 times (i.e., trials) for each 16-min session. The pre-stimulus interval will vary randomly from trial to trial between 4 and 8 seconds to prevent stimulus timing predictability. The stimuli will be presented in a randomized order to prevent category predictability.
Study design
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Image recognition task | Experimental | Combination Product: Functional Magnetic Resonance Imaging (fMRI) with propofolThe stimulus set will include real and scrambled images, where the scrambled images will be created by phase-shuffling a randomly chosen real image from each category to preserve category specific low-level image features. Each object category will include four unique real images and one scrambled image. Each image will be repeated 10 times (i.e., trials) for each 16-min session. The pre-stimulus interval will vary randomly from trial to trial between 4 and 8 seconds to prevent stimulus timing predictability. The stimuli will be presented in a randomized order to prevent category predictability. |
Who may qualify
- Ages
- 18 to 40 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (4 listed)
- Healthy study subjects with American Society of Anesthesiologists (ASA)-1 status.
- Right-handed
- Body mass index (BMI) less than 30.
- All subjects will be English speakers.
Key exclusion criteria (5 listed)
- Medical contraindication to magnetic resonance imaging (MRI) scanning; are unable to undergo MRI scanning because of possible pregnancy or currently breastfeeding, BMI>30, metallic substances in the body, claustrophobia, anxiety, or cardiopulmonary disease; or have an intracranial structural abnormality on T1-weighted MRI scans.
- History of allergy to propofol, eggs or egg products, soybean or soybean products, neurological, cardiovascular, or pulmonary illness; significant head injury with loss of consciousness; learning disability or other developmental disorder; sleep apnea or any severe snoring history; gastroesophageal reflux disease (GERD) or heartburn; pancreatitis or a history of pancreatitis, or sensory/motor loss sufficient to interfere with performance of the study.
- Tattoos in the head or neck region will be excluded from study; other tattoos are subject to determination by investigators based on their assessment regarding participant safety. To eliminate aspiration risk subjects will also be excluded if they have had recent food or liquid intake (within 8 hours).
- History of drug use, have a positive drug screen, are unwilling to abstain from alcohol for 24 hours prior to dosing, or have a current history of nicotine use.
- Pregnancy
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Functional Magnetic Resonance Imaging (fMRI) with propofolThree 16-min sessions in wakeful baseline, light sedation, and recovery will be conducted (Fig. 2). Light sedation will be achieved by IV infusion of propofol to achieve effect-site concentrations of 1.0 μg/ml. Infusion rate will be manually controlled. An initial bolus dose (525 µg/kg) and subsequent infusion rate (82 µg/kg/min) for each participant | Combination product | Image recognition task |
Primary outcome
Blood Oxygen Level Dependent (BOLD) Response to Visual Stimuli
Time frame: Up to 90 minutes
Blood oxygen level-dependent (BOLD) responses during a near-threshold visual recognition task were estimated using AFNI (Analysis of Functional NeuroImages). Response estimates were extracted from the fusiform gyrus region of interest at awake baseline and during light propofol sedation. Voxel time series were normalized to zero mean and unit variance, and response values are reported in arbitrary units (AU), not percent BOLD signal change. Higher AU values indicate a greater estimated stimulus-related BOLD response in this region. The results report baseline and sedation values separately.
2 secondary outcomes
Perceptual Criterion (c) Derived From the Signal Detection Theory (SDT)
Time frame: Up to 90 minutes
Sensitivity (d') Derived From the Signal Detection Theory (SDT)
Time frame: Up to 90 minutes
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 30 Oct 2026.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Zirui Huang principal investigator
University of Michigan
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Functional Magnetic Resonance Imaging (fMRI) with propofol in people with Propofol and Anesthesia, run by University of Michigan at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 30 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
Yes. Results are posted in the registry (first posted 30 Oct 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Blood Oxygen Level Dependent (BOLD) Response to Visual Stimuli (time frame: Up to 90 minutes). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 30 Oct 2026.