The Brain Metabolism of Unpredictable Signals
Quantifying the Brain Metabolism Underlying Task-Based BOLD Imaging
Study Overview
Status
Conditions
Intervention / Treatment
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 Type
Enrollment (Actual)
Phase
- Not Applicable
Contacts and Locations
Study Locations
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Massachusetts
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Charlestown, Massachusetts, United States, 02129
- Athinoula A. Martinos Center for Biomedical Imaging
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Participation Criteria
Eligibility Criteria
Ages Eligible for Study
Accepts Healthy Volunteers
Description
Inclusion Criteria:
- Adults aged 21-35.
- No contraindications to MRI or PET scanning.
- Right-handed.
- Fluent to speak, read, and understand English.
Exclusion Criteria:
- 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
- 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
Study Plan
How is the study designed?
Design Details
- Primary Purpose: Basic Science
- Allocation: N/A
- Interventional Model: Single Group Assignment
- Masking: None (Open Label)
Arms and Interventions
Participant Group / Arm |
Intervention / Treatment |
|---|---|
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Experimental: Behavioral intervention
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.
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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).
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What is the study measuring?
Primary Outcome Measures
Outcome Measure |
Measure Description |
Time Frame |
|---|---|---|
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Brain positron emission tomography (PET) imaging signals
Time Frame: after PET image analysis and with study completion, an average of 1 year
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Changes in glucose metabolism will be quantified from brain PET images
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after PET image analysis and with study completion, an average of 1 year
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Functional magnetic resonance imaging (fMRI) signals
Time Frame: after fMRI image analysis and with study completion, an average of 1 year
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Changes in oxygen metabolism will be quantified from dual-calibrated fMRI
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after fMRI image analysis and with study completion, an average of 1 year
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Oxygen-glucose index
Time Frame: after PET/fMRI image analysis and with study completion, an average of 1 year
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Ratio of cerebral metabolic rates of glucose and oxygen from PET and fMRI signals
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after PET/fMRI image analysis and with study completion, an average of 1 year
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Collaborators and Investigators
Sponsor
Investigators
- Principal Investigator: Christin Y Sander, PhD, Athinoula A. Martinos Center for Biomedical Imaging
Study record dates
Study Major Dates
Study Start (Actual)
Primary Completion (Actual)
Study Completion (Actual)
Study Registration Dates
First Submitted
First Submitted That Met QC Criteria
First Posted (Actual)
Study Record Updates
Last Update Posted (Actual)
Last Update Submitted That Met QC Criteria
Last Verified
More Information
Terms related to this study
Other Study ID Numbers
- 2022P002851
Plan for Individual participant data (IPD)
Plan to Share Individual Participant Data (IPD)?
Drug and device information, study documents
Studies a U.S. FDA-regulated drug product
Studies a U.S. FDA-regulated device product
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