title: Inherited auditory-cortical dysfunction in twin pairs discordant for schizophrenia.
abstract: BACKGROUND
  Information on the inheritance of neurophysiological abnormalities might help elucidate the molecular genetic basis of schizophrenia. We used magnetoencephalography (MEG) and electroencephalography (EEG) to investigate the inheritance of auditory-cortical deficiencies in twin pairs discordant for schizophrenia.
  
  
  METHODS
  Auditory EEG/MEG responses to frequent standard and occasional deviant tones were measured in mono- and dizygotic (MZ and DZ) twin pairs discordant for schizophrenia and demographically matched healthy twin pairs, recruited from a total population cohort. The MEG/EEG results were regressed against the genetic resemblance to patients with schizophrenia across the patients' unaffected MZ/DZ co-twins and control subjects (with genetic correlations of 1, .5, and 0 to schizophrenia patients, respectively).
  
  
  RESULTS
  The EEG responses P50, N100, and mismatch negativity (MMN), as well as the MEG response P50m, were reduced in the schizophrenic patients. P50 and N100 were significantly decreased also in their unaffected co-twins, as compared with the control subjects. Importantly, the P50 and N100 decrease correlated with the unaffected subjects' genetic resemblance to schizophrenia patients.
  
  
  CONCLUSIONS
  Our results suggest inherited abnormalities in cortical auditory processing in schizophrenia, reflected by the decreased P50/P50m and N100 amplitudes, whereas the MMN abnormalities might reflect predominantly state-dependent neurodegeneration.
authors.affiliation: Department of Radiology, Harvard Medical School-Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA. jyrki@nmr.mgh.harvard.edu
authors.forename: Jyrki
authors.initials: J
authors.lastname: Ahveninen
authors.forename: Iiro P
authors.initials: IP
authors.lastname: Jääskeläinen
authors.forename: Daria
authors.initials: D
authors.lastname: Osipova
authors.forename: Matti O
authors.initials: MO
authors.lastname: Huttunen
authors.forename: Risto J
authors.initials: RJ
authors.lastname: Ilmoniemi
authors.forename: Jaakko
authors.initials: J
authors.lastname: Kaprio
authors.forename: Jouko
authors.initials: J
authors.lastname: Lönnqvist
authors.forename: Marko
authors.initials: M
authors.lastname: Manninen
authors.forename: Satu
authors.initials: S
authors.lastname: Pakarinen
authors.forename: Sebastian
authors.initials: S
authors.lastname: Therman
authors.forename: Risto
authors.initials: R
authors.lastname: Näätänen
authors.forename: Tyrone D
authors.initials: TD
authors.lastname: Cannon
mesh_terms: D001931:Brain Mapping; D016022:Case-Control Studies; D004200:Diseases in Twins / Q000503:physiopathology*; D004569:Electroencephalography / Q000379:methods; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D006311:Hearing Disorders / Q000209:etiology*; D006801:Humans; D015225:Magnetoencephalography / Q000379:methods; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D011930:Reaction Time / Q000502:physiology; D012189:Retrospective Studies; D012559:Schizophrenia / Q000150:complications / Q000235:genetics / Q000503:physiopathology; D012565:Schizophrenic Psychology; D018433:Twin Studies as Topic