Neurolmage 11, Number 5, 2000, Part 2 of 2 Parts ID E h,@ DISORDERS - PSYCHIATRY Hypofrontality in Schizophrenia - A combined Phosphorus-CSI and fMRI Study Stefan Riehemann, Stefan Smesny, Peggy Stiitzer, Christian Gaser, Hans-Peter Volz, Karl-Jiirgen Blr, Heinrich Sauer Department of Psychiatry, University of Jena, Philosophenweg 3, D-07743 Jena, Germany Introduction One major finding of functional brain imaging studies in schizophrenia is the “hypofrontality” [ 1,2], a decreased activation of the frontal lobes in schizophrenics. Hypofrontality results in or must be based on a reduced energy consumption in the corresponding brain areas, as demonstrated by glucose positron emission tomography (‘“FDG PET, see e.g. [3]) and phosphorus magnetic resonance spectroscopy (“P-MRS, see e.g. 141). It has been demonstrated that the performance of frontal specific neuropsycho- logical tasks. such as the Wisconsin Card Sorting Test (WCST), correlates with the concentrations of high-energy phosphates [5]. Thus, simultaneous investigations of functional brain activity and concentrations of metabolites involved in energy utilization would be useful. With this type of study design a modified energy consuming process in the frontal lobes of schizophrenics that results in functional hypofrontality could be confirmed. Thus, we performed a combined functional magnetic resonance imaging (fMR1) and “P-MRS chemical shift imaging (CSI) study on neuroleptica-free schizophrenic inpatients and healthy controls. For the fMR1 part of the study we used the WCST and an adequate control condition as stimuli to detect activated frontal brain regions. Methods We investigated 23 unmedicated schizophrenic patients and 21 healthy controls. Due to motion artefacts during the NRI measurement and a low test performance we had to exclude 13 patients and 2 controls from the study. So we finally included in the evaluation 10 unmedicated schizophrenic patients (6 female, 4 male, age 38.229.2 years) and 10 healthy controls matched for gender, education and age (35.829.7 years). Both MRI investigations were performed within one session on a Philips Gyroscan ACSII scanner at 1.5T. For the fMR1 study we used a FLASH sequence acquiring 4 slices, and for the 3’P-MRS study we used a CSI sequence which records the same anatomical areas as within the fMR1 study. fMRI data were evaluated using the random effects model of SPM96 [6]. CSI data were preprocessed first to generate metabolic images of anorganic phosphate Pi, phosphocreatine PCr and adenosine-triphosphate ATP [7]. Group differences between these images were visualized using SPM96. Results We present the results of WCST specific brain activations. Group differences between schizophrenics and healthy controls are presented for the fMR1 study and for all metabolic CSI images. The resulting group differences of NRI and CSI are compared with each other. The findings are discussed to clarify the causes of hypofrontality. References [I] Andreasen NC, Rezai K. Swayze VW II, Flaum M, Kirchner P, Cohen G. Arch Gen Psychiatry 49 (1992) 943-58. [2] Woods SW. J Clin Psychiatry 53 (1992) 20-25. [3] Schroder J, Buchsbaum MS, Siegel BV. Geider FJ, Haier RJ, Lohr J. Psycho1 Med 24 (1994) 947-955. [4] Volz HP, Rzanny R, Rossger G, Hiibner G, Kreitschmann-Andermahr I, Kaiser WA, Sauer H. Biol Psychiatry 44 (1998) 399-404. [S] Volz HP, Hiibner 0. Rzanny R, Rossger G, Preussler B, Eichhorn M, Kreitschmann-Andermahr 1, Kaiser WA, Sauer H. Schizophrenia Res 3 1 (1998) 37-47. [6] Holmes AP, Friston KJ. NemoImage 7 (1998) S754. [7] Riehemann S. Gaser C. Volz HP, Sauer H. Proc SPIE 3661 (1999) 1219.1226. s194