Alteration of intracerebral metabolites and subjective sleepiness by acute caffeine administration in adults.

Motivation: The effects of acute caffeine intake on brain metabolite levels remain largely unknown. Goal(s): Illustrate the sensitivity of MRS to fluctuations in brain metabolites, investigate the difference among different caffeine consumption habit groups and to explore the association between metabolite changes and sleepiness. Approach: MRS was performed at three time point after the participants consumed coffee. Results: GABA+, GPC/GPC + PCH, Ins, Glu, and Glx levels were significantly altered after caffeine consumption. The levels of Glu, GPC, Cr + PCr, Glx, and Ins were significantly influenced by caffeine consumption habits. GABA+ levels in TH voxels significantly correlate with subjective sleepiness. Impact: This study should prove valuable in the study of the sensitivity of MRS to fluctuations in brain metabolites, the brain metabolites alteration differences among different coffee consumption habits, and MRS studies of GABA.