MEG neuroimaging of delusions in episodic interictal psychosis of epilepsy R. Ishii a, ⁎ , L. Canuet a,b , M. Iwase a , R. Kurimoto a , K. Ikezawa a , S.E. Robinson c , S. Ukai d , K. Shinosaki d , M. Hirata e , T. Yoshimine e , M. Takeda a a Department of Clinical Neuroscience, Psychiatry, Osaka University Graduate School of Medicine, Yamadaoka 2-2, D-3, Suita, Osaka 565-0871, Japan b Department of Neurology, “Saturnino Lora” Provincial Hospital, Santiago de Cuba, Cuba c VSM MedTech Ltd., CTF Systems, Canada d Department of Neuropsychiatry, Wakayama Medical University, Japan e Department of Neurosurgery, Osaka University Graduate School of Medicine, Japan Abstract. Although delusions are quite common symptoms among psychiatric patients, few neuroimaging studies have explored the neural correlates of delusions. In this study we used magnetoencephalography (MEG) to directly image brain activity associated with delusions in acute psychosis of epilepsy patients. Two female patients aged 65 and 68 years with temporal lobe epilepsy were studied. We obtained topographic images of the excess kurtosis (g2), the statistical index of spiky activities, from unaveraged MEG measurements using an analysis called “synthetic aperture magnetometry” (SAM). In both patients, the excess kurtosis (g2) images showed spiky activity over the right inferior parietal cortex during the delusional state. A second MEG measurement after delusions were resolved with antipsychotic medication showed no excess kurtosis image in the right parietal cortex. Our results indicate association of the right inferior parietal region with the experience of delusions in these patients. We suggest that MEG with SAM analysis is useful in the identification of abnormal activity in acute psychotic disorders. © 2007 Elsevier B.V. All rights reserved. Keywords: Synthetic aperture magnetometry (SAM); Kurtosis; Magnetoencephalography; Delusions; Epilepsy psychosis International Congress Series 1300 (2007) 649 – 652 www.ics-elsevier.com ⁎ Corresponding author. Tel.: +81 6 6879 3051; fax: +81 6 6879 3059. E-mail address: ishii@psy.med.osaka-u.ac.jp (R. Ishii). 0531-5131/ © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.ics.2007.02.012