title: Caffeine reduces resting-state BOLD functional connectivity in the motor cortex.
abstract: In resting-state functional magnetic resonance imaging (fMRI), correlations between spontaneous low-frequency fluctuations in the blood oxygenation level dependent (BOLD) signal are used to assess functional connectivity between different brain regions. Changes in resting-state BOLD connectivity measures are typically interpreted as changes in coherent neural activity across spatially distinct brain regions. However, this interpretation can be complicated by the complex dependence of the BOLD signal on both neural and vascular factors. For example, prior studies have shown that vasoactive agents that alter baseline cerebral blood flow, such as caffeine and carbon dioxide, can significantly alter the amplitude and dynamics of the task-related BOLD response. In this study, we examined the effect of caffeine (200 mg dose) on resting-state BOLD connectivity in the motor cortex across a sample of healthy young subjects (N=9). We found that caffeine significantly (p<0.05) reduced measures of resting-state BOLD connectivity in the motor cortex. Baseline cerebral blood flow and spectral energy in the low-frequency BOLD fluctuations were also significantly decreased by caffeine. These results suggest that caffeine usage should be carefully considered in the design and interpretation of resting-state BOLD fMRI studies.
authors.affiliation: Center for Functional Magnetic Resonance Imaging, University of California San Diego, La Jolla, CA 92093-0677, USA.
authors.forename: Anna Leigh
authors.initials: AL
authors.lastname: Rack-Gomer
authors.forename: Joy
authors.initials: J
authors.lastname: Liau
authors.forename: Thomas T
authors.initials: TT
authors.lastname: Liu
mesh_terms: D000328:Adult; D002110:Caffeine / Q000494:pharmacology*; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D002560:Cerebrovascular Circulation / Q000187:drug effects; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D009044:Motor Cortex / Q000098:blood supply / Q000187:drug effects*; D009434:Neural Pathways / Q000187:drug effects*; D012146:Rest
chemical_list: D000697:Central Nervous System Stimulants; D002110:Caffeine