title: Source distribution of neuromagnetic slow waves and MEG-delta activity in schizophrenic patients.
abstract: BACKGROUND
  Schizophrenic patients exhibit more activity in the electroencephalographic delta and theta frequency range than do control subjects. Using magnetic source imaging (MSI) our study aimed to explore this phenomenon in the magnetoencephalogram (MEG), the distribution of its sources, and associations between symptom profiles and sources of low-frequency activity in the brain.
  
  
  METHODS
  Whole-head MEG recordings were obtained from 28 schizophrenic patients and 20 healthy control subjects during a resting condition. The generators of the focal magnetic slow waves were located employing a single moving dipole model. Distributed or multiple delta and theta sources were captured by the minimum norm estimate.
  
  
  RESULTS
  Both localization procedures showed slow wave activity to be enhanced in schizophrenic patients compared with control subjects. Focal slow wave activity differed most between groups in frontotemporal and in posterior regions. Slow wave activity was associated with symptom characteristics in that positive symptoms varied with frontal delta and theta activity.
  
  
  CONCLUSIONS
  Results indicate that activity in low-frequency bands in schizophrenic patients exceeds the activity of control subjects in distinct areas, and that this focal clustering of neuromagnetic slow waves may be related to psychopathologic characteristics.
authors.affiliation: Department of Psychology, University of Konstanz, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Fehr
authors.forename: J
authors.initials: J
authors.lastname: Kissler
authors.forename: S
authors.initials: S
authors.lastname: Moratti
authors.forename: C
authors.initials: C
authors.lastname: Wienbruch
authors.forename: B
authors.initials: B
authors.lastname: Rockstroh
authors.forename: T
authors.initials: T
authors.lastname: Elbert
mesh_terms: D000328:Adult; D001931:Brain Mapping; D003700:Delta Rhythm; D005260:Female; D006801:Humans; D015225:Magnetoencephalography; D008297:Male; D012559:Schizophrenia / Q000503:physiopathology*; D012565:Schizophrenic Psychology; D013826:Theta Rhythm