An interventional study of Low-intensity focused ultrasound pulsation (LIFUP) and Functional Magnetic Resonance Imaging (fMRI) in Consciousness, Level Altered, sponsored by University of Michigan. Not yet recruiting at 1 site in United States. Open to participants aged 18 Years to 40 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-10-13.
Sponsored by University of Michigan · Not applicable, Interventional, and Basic science
This research is studying changes in awareness and metabolism in the brain that may take place in various brain regions stimulated with ultrasound (low-intensity focused ultrasound pulsation or LIFUP) while undergoing magnetic resonance imaging (MRI)-based brain measurements.
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
290 studies on the registry are indexed under Consciousness Disorders; 109 are open to participants now.
This study's planned enrollment of 90 is above the median of 47 across 191 interventional studies indexed under Consciousness Disorders.
Browse Consciousness Disorders studies →University of Michigan is the lead sponsor of 1,506 studies on the registry; 192 are open to participants now.
Of its 169 completed or terminated interventional studies of FDA-regulated products, 133 (79%) have results posted.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Childbearing potential
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants assigned to the fMRI arm will complete five visits, with a different brain region targeted at each visit. Each visit will include seven consecutive 10-minute scanning periods: one pre-LIFUP baseline fMRI scan, five fMRI scans conducted during LIFUP using five predefined combinations of duty cycle and pulse repetition frequency, and one post-LIFUP baseline fMRI scan. The five stimulation parameter combinations will be labeled Combination 1 through Combination 5. The order of the five parameter combinations will be randomized within each visit. The total planned scanning time for these seven periods is approximately 70 minutes, excluding structural imaging, participant positioning, transducer placement, safety checks, and other required study procedures.
Device: Low-intensity focused ultrasound pulsation (LIFUP) · Device: Functional Magnetic Resonance Imaging (fMRI)
Participants assigned to the MRS arm will also complete five visits, with a different brain region targeted at each visit. Each visit will include a pre-LIFUP baseline MRS acquisition, an excitatory LIFUP condition, a post-excitatory non-LIFUP MRS acquisition, an inhibitory LIFUP condition, and a post-inhibitory non-LIFUP MRS acquisition. Each MRS acquisition period will last approximately 13 minutes and will include approximately 5 minutes of glutamate plus glutamine measurement and 8 minutes of gamma-aminobutyric acid (GABA) measurement. The order of the excitatory and inhibitory LIFUP conditions will be randomized across participants.
Device: Low-intensity focused ultrasound pulsation (LIFUP) · Device: Magnetic Resonance Spectroscopy
Participants assigned to the glymphatic MRI arm will complete up to five visits, with a different prespecified brain region targeted at each visit. Tissue-to-fluid water exchange, velocity spectrum imaging, and cerebral perfusion using arterial spin labeling will be assessed before, during, and after LIFUP. The planned imaging periods total approximately 1.5 hours per visit, excluding participant positioning, structural imaging, transducer placement, safety checks, and other required study procedures.
Device: Low-intensity focused ultrasound pulsation (LIFUP) · Device: Multi-modal glymphatic function MRI
LIFUP will be used to stimulate specific brain regions and assess their causal involvement in the control of conscious state and contents.
Whole-brain functional images will be acquired using a multiband gradient-echo echo-planar imaging sequence with the following parameters: 60 slices, repetition time (TR) = 800 ms, echo time (TE) = 30 ms, flip angle = 52°, multiband acceleration factor = 6, slice thickness = 2.4 mm, in-plane resolution = 2.4 × 2.4 mm, FOV = 216 × 216 mm, and image matrix = 90 × 90. MRI acquisition and associated study procedures will be completed within a scanning visit lasting no more than approximately 2 hours.
Single-voxel proton magnetic resonance spectroscopy will be performed. A nominal 15 × 15 × 10 mm spectroscopy voxel will be positioned at the prespecified brain target using the participant's anatomical MRI. Glutamate plus glutamine (Glx) will be measured using a short-echo-time spectroscopy sequence with an acquisition time of approximately 5 minutes. GABA will be measured using an edited spectroscopy sequence with an acquisition time of approximately 8 minutes. An unsuppressed water-reference scan will also be acquired for signal correction and metabolite quantification. Voxel placement, shimming, and other sequence parameters may be adjusted slightly based on target anatomy, scanner requirements, and data quality while maintaining the planned procedures and approximate acquisition times.
The study team will collect three separate measurements related to glymphatic function. (i) Multi-delay pseudo-continuous arterial spin labeling (PCASL) MRI with a 3D stack of spirals (SOS) gradient and spin echo (GRASE) read-out. Labeling durations from 500 to 2000 ms, TR = 6 sec., background suppression. FOV = 24 cm with 3x3x5 mm resolution. (ii) Tissue-to-fluid Water exchange rate using T2 selective saturation labeling pulses using the same resolution parameters. (iii) Velocity Spectrum Imaging using velocity selective preparation pulses followed by spherical spiral projection imaging (FOV = 24 cm, velocity bandwidth = \[-1, 1\] cm/s, isotropic spatial resolution = 3.5 mm).
Blood Oxygen Level Dependent (BOLD) response to visual stimuli
Changes in task-evoked blood oxygen level-dependent responses to visual stimuli will be measured using functional MRI before, during, and after LIFUP across the five stimulation parameter conditions.
Time frame: Approximately 70 minutes
Perceptual criterion (c) derived from the Signal Detection Theory (SDT)
The perceptual response criterion, c, will be calculated from participants' recognition responses using Signal Detection Theory to quantify their tendency to report conscious recognition of a visual stimulus. For each scanning session, the study team will calculate sensitivity (d') and criterion (c) using subjective reports of recognition as "yes" or "no".
Time frame: Approximately 65-75 minutes
Perceptual sensitivity (d') derived from the Signal Detection Theory (SDT)
Perceptual sensitivity, d', will be calculated from participants' visual discrimination responses using Signal Detection Theory to quantify their ability to distinguish intact object images from control stimuli. For each scanning session, the study team will calculate sensitivity (d') and criterion (c) using subjective reports of recognition as "yes" or "no".
Time frame: Approximately 75 minutes
Plan to share: No
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From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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