title: Dietary caffeine consumption modulates fMRI measures.
abstract: Caffeine is the most widely used stimulant in the world. The stimulant effects of caffeine are mediated through its antagonistic properties on neuronal adenosine receptors. In addition, caffeine blocks neurovascular adenosine receptors and decreases cerebral perfusion. Although the effects of caffeine on blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging measures are extremely important, there are few studies addressing this issue in the literature. Because chronic caffeine use causes an upregulation of adenosine receptors, the differential effects of caffeine in low and high users is of particular interest. The present study was designed to test the hypothesis that caffeine has differential effects on the BOLD signal in high and low caffeine users. We demonstrated that the BOLD signal change in visual cortex was significantly greater in high users than in low users in the presence of caffeine. In addition, the magnitude of the BOLD signal was significantly correlated with caffeine consumption. We propose that the outcome observed here was due to an upregulation of adenosine receptors in high users, resulting in differential contributions of the neural and vascular effects of adenosine in the two study populations.
authors.affiliation: Department of Radiology, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157-1022, USA.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Laurienti
authors.forename: Aaron S
authors.initials: AS
authors.lastname: Field
authors.forename: Jonathan H
authors.initials: JH
authors.lastname: Burdette
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Maldjian
authors.forename: Yi-Fen
authors.initials: YF
authors.lastname: Yen
authors.forename: Dixon M
authors.initials: DM
authors.lastname: Moody
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001921:Brain / Q000187:drug effects / Q000502:physiology*; D001931:Brain Mapping; D002110:Caffeine / Q000494:pharmacology*; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D003069:Coffee; D004032:Diet; D004311:Double-Blind Method; D005260:Female; D005403:Fixation, Ocular / Q000502:physiology; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D010775:Photic Stimulation; D014793:Visual Cortex / Q000502:physiology
chemical_list: D000697:Central Nervous System Stimulants; D003069:Coffee; D002110:Caffeine; D010100:Oxygen