Fax +41 61 306 12 34 E-Mail karger@karger.ch www.karger.com Original Paper Neuropsychobiology 2007;55:89–95 DOI: 10.1159/000103907 Specific and Unspecific Auditory Hallucinations in Patients with Schizophrenia A Magnetoencephalographic Study Udo Reulbach a Stefan Bleich a Christian Maihöfner b Johannes Kornhuber a Wolfgang Sperling a a Department of Psychiatry and Psychotherapy and b Department of Neurology, Friedrich Alexander University of Erlangen-Nuremberg, Erlangen-Nuremberg, Germany ent qualities of hallucinations. In patients with external imperative voices we found a parallel activation of the dorsolateral frontal and temporal cortex. Conclusion: We conclude that various auditory hallucinations in schizophre- nia are induced by different neuronal activities and may be represented by different cortical regions. Copyright © 2007 S. Karger AG, Basel Introduction Spontaneous magnetoencephalographic (MEG) activ- ity in schizophrenic patients has been investigated in nu- merous studies. The majority of these investigations re- vealed significant differences mainly in the temporal re- gion between schizophrenics and healthy controls [1–5]. In the past, differentiated psychopathological and pathogenetical analysis concentrated on auditory hallu- cinations, which are a core feature of schizophrenia. In several new studies alterations in connectivity between frontal and parietotemporal speech-related areas were discussed in the pathogenesis of auditory hallucinations [6, 7] . A failure of corollary discharge, a mechanism for distinguishing self-generated from externally generated Key Words Magnetoencephalography  Positive symptoms  Schizophrenia  Auditory hallucinations Abstract Background/Aims: Different neuroimaging techniques have indicated that auditory association and language cor- tices are active in patients with schizophrenia and auditory hallucinations. Auditory verbal hallucinations are thought to arise from a disorder of inner speech, but little is known about their origin. Methods: Spontaneous magnetoen- cephalographic (MEG) measurements were recorded with a 74-channel two-sensor system (BIOMAGNES II) in 16 patients with schizophrenia and 8 healthy subjects in frequency ranges from 2 to 6 and 12.5 to 30 Hz. Eight patients had audi- tory hallucinations during the MEG recordings. Results: The total group of patients with schizophrenia showed a statisti- cally significant elevation of the number of dipoles and di- pole density maxima in slow frequency ranges compared to healthy subjects (p ! 0.001). Significant dipole activities in the fast frequency range were only found during auditory hallucinations (p ! 0.001). Dipole localization was concen- trated in frontal and temporal regions depending on differ- Received: July 17, 2006 Accepted after revision: March 17, 2007 Published online: June 15, 2007 Prof. Dr. Wolfgang Sperling, Department of Psychiatry and Psychotherapy Friedrich Alexander University of Erlangen-Nuremberg Schwabachanlage 6, DE–91052 Erlangen (Germany) Tel. +49 9131 853 6194, Fax +49 9131 853 6092 E-Mail wolfgang.sperling@uk-erlangen.de © 2007 S. Karger AG, Basel 0302–282X/07/0552–0089$23.50/0 Accessible online at: www.karger.com/nps