Brain metabolism in early stage of schizophrenia remains a subject of studies. The data on the local concentrations of proton-containing metabolites are contradictive. 31P MRS magnetization transfer study revealed decreased rate constant of forward creatine kinase reaction in frontal lobe of never medicated schizophrenia patients [1]. Metabolic alterations in schizophrenia might be revealed during stimulation that allows to analyze metabolic response on energy consuming processes. Using dynamic 1H MRS we obtained different NAA kinetics in the motor cortex in the norm and in early stage schizophrenia patients in response to single short stimulus [2, 3]. The purpose of this study is to reveal stimulation effects on 31P MRS detectible metabolites in activated cortex in the norm and in early stage schizophrenia patients.Subjects of the study were 12 patients at early stage schizophrenia (F20, ICD-10) (mean age 21.2 ± 5.5) and 20 neurologically and psychiatrically healthy age-matched subjects. Philips Achieva 3.0T, Dual 31P/1H bird-cage coil for 31P 2D MRS and Eloquence In vivo station for visual stimuli transmitting were used. All participants passed a standard anatomic examination and fMRI (EPI, TE=35ms, TR=3000ms, FA=90°) revealing zones of visual cortex activation in response to watching a flashing checkerboard. Parameters of 2D 31P spectroscopy were: pulse sequence ISIS, TE=0.3ms, TR=1200ms, FA=35°. fMRI activation map was used for better spectroscopic volume locating in visual cortex (Fig. 1). Firstly, spectra acquisition was performed in resting state and then during continuous visual stimulation by a 6 Hz flashing checkerboard. Each spectrum acquisition took 6 minutes. Postprocessing and quantification were performed in jMRUI using AMARES algorithm. FIDs of two voxels containing visual cortex were averaged, amplitudes of individual resonances in spectrum recorded during excitation were normalized to corresponding values obtained from the spectra recorded in resting state. ATP concentration was measured using β-ATP peak.Fig.2 shows representative ³¹P MR spectrum acquired in visual cortex. No difference was found between PCr/β-ATP in visual cortex of healthy subjects and patients in resting state. Visual stimulation causes statistically significant (p<0.01) decrease of PCr in visual cortex in the norm while no stimulation-induced effect on PCr in the group of schizophrenia patients was revealed (Fig. 3). Visual stimulation had no effect on β-ATP in both groups; no statistically significant pH changes in any group were revealed either.The data obtained for normal subjects allow to conclude that in response to visual stimulation ATP is regenerated by creatine kinase reaction. No stimulation-induced PCr changes in schizophrenia may reflect disorders in creatine kinase system [1] and/or reduced energy consumption in the period of neuroactivation. The latter agrees with absence of NAA decrease in motor cortex of early stage schizophrenia patients in response to single stimuli [2]. NAA indirectly participates in energy metabolism [4]. The results of our studies allow to propose the scheme of neuronal energetics response to stimulation in initial stage of schizophrenia. (Fig. 3). The obtained data might reflect reduced energy expenses under neurostimulation in early stage of schizophrenia caused probably by decreased activity of energy dependent processes of glutamate transport [5].A new scheme of neuronal energy metabolism in activated cerebral cortex is offered for early stage schizophrenia.