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Cerebral glucose utilization is reduced in second test session
J M Stapleton1, M J Morgan, X Liu
1Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland, USA.
Summary
Anxiety levels significantly impact brain glucose metabolism in repeated positron emission tomography (PET) scans. Low-anxiety individuals showed decreased metabolism over time, unlike high-anxiety subjects, highlighting anxiety as a key factor in PET research.
Area of Science:
- Neuroscience
- Medical Imaging
- Psychophysiology
Background:
- Positron emission tomography (PET) is a neuroimaging technique used to measure brain metabolism.
- Anxiety is a psychological state that can influence physiological processes, including brain activity.
- Repeated PET sessions in human volunteers may be affected by psychological factors like anxiety.
Purpose of the Study:
- To investigate the effect of trait anxiety levels on cerebral glucose utilization during repeated PET sessions.
- To determine if anxiety influences changes in brain metabolism over time in PET studies.
- To examine hemispheric differences in cerebral metabolism related to anxiety levels.
Main Methods:
- Utilized [18F]fluorodeoxyglucose ([18F]FDG) PET to assess cerebral glucose metabolism in male human volunteers.
- Conducted two PET sessions for each participant.
- Categorized participants into low-trait anxiety and high-trait anxiety groups based on pre-study assessments.
Main Results:
- Cerebral glucose utilization was significantly higher in the first PET session compared to the second session.
- This decrease in metabolism over sessions was primarily observed in low-trait anxiety subjects.
- High-anxiety subjects exhibited similar cerebral metabolism across both PET sessions.
- High-anxiety subjects demonstrated greater right/left cerebral metabolism ratios than low-anxiety subjects, especially in the second session.
Conclusions:
- Trait anxiety is a critical confounding variable in longitudinal PET studies assessing cerebral glucose metabolism.
- The observed changes in glucose utilization over repeated sessions are dependent on an individual's anxiety level.
- Future PET research employing multiple sessions should account for participants' anxiety levels to ensure accurate interpretation of metabolic data.