fMRI is widely used to study cerebral metabolism to stimulus through combination of BOLD and hemodynamic changes. Hyperpolarized carbon can also be used to study cerebral metabolism, but it is currently poorly understood. Here we performed simultaneous 1H fMRI and 13C MRS experiments to compare their response to nicotine stimulus. Cortical BOLD signal increase was accompanied by increased bicarbonate labelling. Combined 1H fMRI and 13C MRS may therefore offer complementary information on brain response to stimulus.