Brain imaging and the effects of caffeine and nicotine

Caffeine and nicotine are the most common psychostimulant drugs used worldw ide. Structural neuroimaging findings associated with caffeine and nicotine consumption are limited and primarily reflect the putative relationship be tween smoking and white matter hyperintensities (WMH), a finding that warra nts further appraisal of its clinical implications. The application of newe r brain imaging modalities that measure subtle haemodynamic changes or tiss ue-based chemistry in order to better elucidate brain functional processes, including mechanisms underlying addiction to nicotine and caffeine and the brain functional consequences, provide intriguing findings. Potential infl uences of caffeine and nicotine on the functional contrast, or metabolic re sponse, to neural activation also necessitates the careful appraisal of the effects that these commonly used drugs may have on the results of function al imaging.