Dynamics of human brain metabolites during prolonged visual stimulation as revealed by 1H-MRS at 7 T
Mangia S, Tkac I, Gruetter R, Van De Moortele P, Ugurbil K, Maraviglia B
University of Minnesota
By means of ultra-short echo-time STEAM (TE = 6 ms), we determined on twelve subjects the time-course of lactate and other metabolites during prolonged visual stimulation at 7 T. The group analysis revealed significant concentration changes for lactate (+20%), glutamate (+2%), aspartate (-20%) and glucose (-15%). In general, changes in metabolite concentrations were within 0.2 &[mu]mol/g. Lactate increased within 1-2 min by about 0.2 &[mu]mol/g and returned to baseline after the stimulus ended. The reported changes of opposite sign in aspartate and glutamate implicated that amino-acid homeostasis is affected by physiological stimulations.