HealthyNCT05756335
The Brain Metabolism of Unpredictable Signals
A study testing (Un)predictable and (un)attended stimuli in people with Healthy, run by Massachusetts General Hospital at 1 site in United States.
Trial summary
The investigators will be studying brain glucose and oxygen metabolism using hybrid PET/fMRI imaging to better understand how decoupling between brain glucose and oxygen metabolism relates to the processing of unpredictable sensory signals. Read more about this study
- Who is it for?
- Ages 21 to 35 yearsHealthy volunteers can take part
- Conditions the study is for
- Healthy
- What is being tested?
- (Un)predictable and (un)attended stimuli
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 24 participants
- Where
- 1 siteUnited States
- Study dates
- 5 Apr 2024to 12 Feb 2026
- Phase
- Interventional
- Are there results?
- None posted in the registry
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 21 to 35 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Adults aged 21-35.
- No contraindications to MRI or PET scanning.
- Right-handed.
- Fluent to speak, read, and understand English.
Who cannot join
- Adults unable to consent
- Contraindications to fMRI scanning and PET scanning (including the presence of a cardiac pacemaker or pacemaker wires, metallic particles in the body, vascular clips in the head or previous neurosurgery, prosthetic heart valves, claustrophobia)
- Inability to lie motionless in the scanner
- Pregnancy, seeking or suspecting pregnancy, or breastfeeding
- History of major head trauma
- Intracranial lesion
Show all 28Show fewer
- Cardiovascular disorders, including heart disorders or high blood pressure [>155/95]
- Breathing problems such as severe asthma, emphysema, or pulmonary disease
- Bleeding disorder, or use of anticoagulants
- Bladder obstruction, urinary problems, or history of impaired elimination
- Known kidney or liver problems
- Past severe COVID-19 infection
- Intestinal blockage
- Raynaud syndrome
- Anemia
- Peripheral nerve injury
- Diabetes
- Glaucoma
- Current or recent use of medications (neurological or psychiatric) affecting brain function
- Current or past history of major medical, neurological, or psychiatric condition
- Current or past history of chronic pain (assessed at the discretion of PI)
- Current smoker
- Body mass index above 35
- Research-related radiation exposure exceeds current Radiology Department guidelines
- Lack of current health insurance coverage
- Employed under the direct supervision of the investigators conducting the research
- Unwilling or unable to cooperate with breathing maneuvers required during the gas challenge
- Respiratory or cardiac limitations to breathing at 20 L/min
Trial locations and contacts
1 site in 1 country.
United States1 site
Athinoula A. Martinos Center for Biomedical Imaging
Charlestown, Massachusetts, 02129
About this study
Official title: Quantifying the Brain Metabolism Underlying Task-Based BOLD Imaging
The investigators will be studying brain glucose and oxygen metabolism using hybrid PET/fMRI imaging to better understand how decoupling between brain glucose and oxygen metabolism relates to the processing of unpredictable sensory signals.
Read the detailed description
The proposed research consists of one experiment, combining positron emission tomography (PET) and magnetic resonance imaging (MRI) techniques to simultaneously estimate the cerebral metabolic rates of glucose (CMRglc) and oxygen (CMRO2), and their ratio (oxygen:glucose index; OGI). These outcome measures will be collected in the context of a behavioral intervention presenting subjects with predictable and unpredictable stimuli, and attended and unattended stimuli. Functional PET uses a slow infusion of 2-[18F]-fluro-deoxyglucose (FDG) to estimate regional CMRglc, measuring relative changes in radiotracer uptake between blocks of task and rest. Dual-calibrated fMRI uses a sequence of hyperoxic (increased O2) and hypercapnic (increased CO2) challenges, along with a specialized sequence of MRI scans (estimating cerebral blood flow and blood-oxygen level-dependent signal) to estimate absolute CMRO2.
All subjects will be scanned, and each will complete the same behavioral intervention. First, the investigators will aim to assess the reliability of this hybrid imaging technique by having subjects complete two identical scan sessions. Second, the investigators will deliver a behavioral intervention to test the relationship between stimuli predictability, CMRglc, CMRO2, and OGI.
This experimental design is capable of producing effects observable in single subjects, and prior studies using fPET and dual-calibrated fMRI have produced effect sizes that our sample size is more than adequate to detect.
- Conditions
- Healthy
- Being tested
- (Un)predictable and (un)attended stimuli
- Keywords
- Brain metabolism, Positron Emission Tomography, Magnetic Resonance Imaging
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
(Un)predictable and (un)attended stimuliBehavioural
Subjects will complete four task conditions in each scan session: (1) Visual Unpredictable, (2) Visual Predictable, (3) Auditory Unpredictable, and (4) Auditory Predictable. In visual and auditory conditions subjects attend to visual or auditory stimuli and ignore the other domain, pressing a button when they detect an infrequently occurring stimulus inversion in the target domain. In unpredictable and predictable conditions, the attended domain either presents random (unpredictable) stimuli, or the same face or word stimuli repeated (predictable).
| Study group | Role | What they receive |
|---|---|---|
| Behavioral intervention | Experimental | Subjects are presented with a simultaneous sequence of faces and spoken words. Face stimuli include a representative sample of realistic faces across a range of ages. Spoken word stimuli are simple nouns spoken by a single female speaker. Receives: Behavioral: (Un)predictable and (un)attended stimuli |
What is being measured
The primary outcome is the main question the study is designed to answer.
Brain positron emission tomography (PET) imaging signals
Changes in glucose metabolism will be quantified from brain PET images
Measured: after PET image analysis and with study completion, an average of 1 year
Functional magnetic resonance imaging (fMRI) signals
Changes in oxygen metabolism will be quantified from dual-calibrated fMRI
Measured: after fMRI image analysis and with study completion, an average of 1 year
Oxygen-glucose index
Ratio of cerebral metabolic rates of glucose and oxygen from PET and fMRI signals
Measured: after PET/fMRI image analysis and with study completion, an average of 1 year
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted6 Mar 2023
- Study start5 Apr 2024
- Primary completion12 Feb 2026
- Study completion12 Feb 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for HealthyStudies of the same condition, open and under way.
- More trials run by Massachusetts General HospitalThe 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 N/A
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 24 participants (actual)
Sponsor and investigators
- Lead sponsor
- Massachusetts General Hospital
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Christin Y. Sander, PhD, Massachusetts General Hospital
- Investigators
- Christin Y Sander, PhD, Principal investigator, Athinoula A. Martinos Center for Biomedical Imaging
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05756335
- Sponsor's protocol ID
- 2022P002851
- Status last verified
- Jun 2026
- First submitted
- 15 Feb 2023
- Last updated
- 2 Jul 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 2 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Quantifying the Brain Metabolism Underlying Task-Based BOLD Imaging
- ClinicalTrials.gov ID
- NCT05756335
- Acronym / sponsor ID
- 2022P002851
- Conditions
- Healthy
- Keywords
- Brain metabolism, Positron Emission Tomography, Magnetic Resonance Imaging
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 24 participants (actual)
- Lead sponsor
- Massachusetts General HospitalUniversity, hospital or other
- Study start
- 5 Apr 2024 (actual)
- Primary completion
- 12 Feb 2026 (actual)
- Study completion
- 12 Feb 2026 (actual)
- First posted
- 6 Mar 2023 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The investigators will be studying brain glucose and oxygen metabolism using hybrid PET/fMRI imaging to better understand how decoupling between brain glucose and oxygen metabolism relates to the processing of unpredictable sensory signals.
Detailed description
The proposed research consists of one experiment, combining positron emission tomography (PET) and magnetic resonance imaging (MRI) techniques to simultaneously estimate the cerebral metabolic rates of glucose (CMRglc) and oxygen (CMRO2), and their ratio (oxygen:glucose index; OGI). These outcome measures will be collected in the context of a behavioral intervention presenting subjects with predictable and unpredictable stimuli, and attended and unattended stimuli. Functional PET uses a slow infusion of 2-[18F]-fluro-deoxyglucose (FDG) to estimate regional CMRglc, measuring relative changes in radiotracer uptake between blocks of task and rest. Dual-calibrated fMRI uses a sequence of hyperoxic (increased O2) and hypercapnic (increased CO2) challenges, along with a specialized sequence of MRI scans (estimating cerebral blood flow and blood-oxygen level-dependent signal) to estimate absolute CMRO2.
All subjects will be scanned, and each will complete the same behavioral intervention. First, the investigators will aim to assess the reliability of this hybrid imaging technique by having subjects complete two identical scan sessions. Second, the investigators will deliver a behavioral intervention to test the relationship between stimuli predictability, CMRglc, CMRO2, and OGI.
This experimental design is capable of producing effects observable in single subjects, and prior studies using fPET and dual-calibrated fMRI have produced effect sizes that our sample size is more than adequate to detect.
Study design
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Behavioral intervention | Experimental | Behavioral: (Un)predictable and (un)attended stimuliSubjects are presented with a simultaneous sequence of faces and spoken words. Face stimuli include a representative sample of realistic faces across a range of ages. Spoken word stimuli are simple nouns spoken by a single female speaker. |
Who may qualify
- Ages
- 21 to 35 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (4 listed)
- Adults aged 21-35.
- No contraindications to MRI or PET scanning.
- Right-handed.
- Fluent to speak, read, and understand English.
Key exclusion criteria (28 listed)
- Adults unable to consent
- Contraindications to fMRI scanning and PET scanning (including the presence of a cardiac pacemaker or pacemaker wires, metallic particles in the body, vascular clips in the head or previous neurosurgery, prosthetic heart valves, claustrophobia)
- Inability to lie motionless in the scanner
- Pregnancy, seeking or suspecting pregnancy, or breastfeeding
- History of major head trauma
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 |
|---|---|---|
| (Un)predictable and (un)attended stimuliSubjects will complete four task conditions in each scan session: (1) Visual Unpredictable, (2) Visual Predictable, (3) Auditory Unpredictable, and (4) Auditory Predictable. In visual and auditory conditions subjects attend to visual or auditory stimuli and ignore the other domain, pressing a button when they detect an infrequently occurring stimulus inversion in the target domain. In unpredictable and predictable conditions, the attended domain either presents random (unpredictable) stimuli, or the same face or word stimuli repeated (predictable). | Behavioural | Behavioral intervention |
Primary outcome
Brain positron emission tomography (PET) imaging signals
Time frame: after PET image analysis and with study completion, an average of 1 year
Changes in glucose metabolism will be quantified from brain PET images
Functional magnetic resonance imaging (fMRI) signals
Time frame: after fMRI image analysis and with study completion, an average of 1 year
Changes in oxygen metabolism will be quantified from dual-calibrated fMRI
Oxygen-glucose index
Time frame: after PET/fMRI image analysis and with study completion, an average of 1 year
Ratio of cerebral metabolic rates of glucose and oxygen from PET and fMRI signals
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 2 Jul 2026.
- 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.
Christin Y Sander, PhD principal investigator
Athinoula A. Martinos Center for Biomedical Imaging
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing (Un)predictable and (un)attended stimuli in people with Healthy, run by Massachusetts General Hospital 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 28 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 2 Jul 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.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
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?
Brain positron emission tomography (PET) imaging signals (time frame: after PET image analysis and with study completion, an average of 1 year). The study lists 3 primary outcomes in all. 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 2 Jul 2026.