title: EEG-Informed fMRI Reveals a Disturbed Gamma-Band-Specific Network in Subjects at High Risk for Psychosis.
abstract: OBJECTIVE
  Abnormalities of oscillatory gamma activity are supposed to reflect a core pathophysiological mechanism underlying cognitive disturbances in schizophrenia. The auditory evoked gamma-band response (aeGBR) is known to be reduced across all stages of the disease. The present study aimed to elucidate alterations of an aeGBR-specific network mediated by gamma oscillations in the high-risk state of psychosis (HRP) by means of functional magnetic resonance imaging (fMRI) informed by electroencephalography (EEG).
  
  
  METHODS
  EEG and fMRI were simultaneously recorded from 27 HRP individuals and 26 healthy controls (HC) during performance of a cognitively demanding auditory reaction task. We used single trial coupling of the aeGBR with the corresponding blood oxygen level depending response (EEG-informed fMRI).
  
  
  RESULTS
  A gamma-band-specific network was significantly lower active in HRP subjects compared with HC (random effects analysis, P < .01, Bonferroni-corrected for multiple comparisons) accompanied by a worse task performance. This network involved the bilateral auditory cortices, the thalamus and frontal brain regions including the anterior cingulate cortex, as well as the bilateral dorsolateral prefrontal cortex.
  
  
  CONCLUSIONS
  For the first time we report a reduced activation of an aeGBR-specific network in HRP subjects brought forward by EEG-informed fMRI. Because the HRP reflects the clinical risk for conversion to psychotic disorders including schizophrenia and the aeGBR has repeatedly been shown to be altered in patients with schizophrenia the results of our study point towards a potential applicability of aeGBR disturbances as a marker for the prediction of transition of HRP subjects to schizophrenia.
authors.affiliation: Department of Psychiatry and Psychotherapy, Psychiatry Neuroimaging Branch (PNB) and g.leicht@uke.de.
authors.forename: Gregor
authors.initials: G
authors.lastname: Leicht
authors.affiliation: Department of Psychiatry and Psychotherapy, Psychiatry Neuroimaging Branch (PNB) and.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Vauth
authors.affiliation: Department of Psychiatry and Psychotherapy, Psychiatry Neuroimaging Branch (PNB) and.
authors.forename: Nenad
authors.initials: N
authors.lastname: Polomac
authors.affiliation: Department of Psychiatry and Psychotherapy, Psychiatry Neuroimaging Branch (PNB) and.
authors.forename: Christina
authors.initials: C
authors.lastname: Andreou
authors.affiliation: Department of Psychiatry and Psychotherapy, Psychiatry Neuroimaging Branch (PNB) and.
authors.forename: Jonas
authors.initials: J
authors.lastname: Rauh
authors.affiliation: Department of Psychiatry and Psychotherapy, Psychiatry Neuroimaging Branch (PNB) and.
authors.forename: Marius
authors.initials: M
authors.lastname: Mußmann
authors.affiliation: Department of Psychiatry and Psychotherapy, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Anne
authors.initials: A
authors.lastname: Karow
authors.affiliation: Department of Psychiatry and Psychotherapy, Psychiatry Neuroimaging Branch (PNB) and.
authors.forename: Christoph
authors.initials: C
authors.lastname: Mulert
mesh_terms: D000293:Adolescent; D000328:Adult; D001303:Auditory Cortex / Q000503:physiopathology; D001921:Brain / Q000503:physiopathology*; D016022:Case-Control Studies; D004569:Electroencephalography; D005072:Evoked Potentials, Auditory / Q000502:physiology; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology; D059907:Functional Neuroimaging; D065818:Gamma Rhythm / Q000502:physiology*; D006179:Gyrus Cinguli / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D062706:Prodromal Symptoms; D011618:Psychotic Disorders / Q000503:physiopathology*; D012306:Risk; D012559:Schizophrenia / Q000503:physiopathology*; D013788:Thalamus / Q000503:physiopathology; D055815:Young Adult
keywords: anterior cingulate cortex; auditory cortex; auditory evoked gamma-band response; prodromal state of schizophrenia; simultaneous EEG-fMRI