title: Mismatch negativity in recent-onset and chronic schizophrenia: a current source density analysis.
abstract: Mismatch negativity (MMN) is a component of the event-related potential elicited by deviant auditory stimuli. It is presumed to index pre-attentive monitoring of changes in the auditory environment. MMN amplitude is smaller in groups of individuals with schizophrenia compared to healthy controls. We compared duration-deviant MMN in 16 recent-onset and 19 chronic schizophrenia patients versus age- and sex-matched controls. Reduced frontal MMN was found in both patient groups, involved reduced hemispheric asymmetry, and was correlated with Global Assessment of Functioning (GAF) and negative symptom ratings. A cortically-constrained LORETA analysis, incorporating anatomical data from each individual's MRI, was performed to generate a current source density model of the MMN response over time. This model suggested MMN generation within a temporal, parietal and frontal network, which was right hemisphere dominant only in controls. An exploratory analysis revealed reduced CSD in patients in superior and middle temporal cortex, inferior and superior parietal cortex, precuneus, anterior cingulate, and superior and middle frontal cortex. A region of interest (ROI) analysis was performed. For the early phase of the MMN, patients had reduced bilateral temporal and parietal response and no lateralisation in frontal ROIs. For late MMN, patients had reduced bilateral parietal response and no lateralisation in temporal ROIs. In patients, correlations revealed a link between GAF and the MMN response in parietal cortex. In controls, the frontal response onset was 17 ms later than the temporal and parietal response. In patients, onset latency of the MMN response was delayed in secondary, but not primary, auditory cortex. However amplitude reductions were observed in both primary and secondary auditory cortex. These latency delays may indicate relatively intact information processing upstream of the primary auditory cortex, but impaired primary auditory cortex or cortico-cortical or thalamo-cortical communication with higher auditory cortices as a core deficit in schizophrenia.
authors.affiliation: Centre for Translational Neuroscience and Mental Health, The University of Newcastle, Newcastle, New South Wales, Australia; Schizophrenia Research Institute, Darlinghurst, New South Wales, Australia; Hunter Medical Research Institute, Newcastle, New South Wales, Australia.
authors.forename: W Ross
authors.initials: WR
authors.lastname: Fulham
authors.affiliation: Centre for Translational Neuroscience and Mental Health, The University of Newcastle, Newcastle, New South Wales, Australia; Schizophrenia Research Institute, Darlinghurst, New South Wales, Australia; School of Psychology, The University of Newcastle, Newcastle, New South Wales, Australia.
authors.forename: Patricia T
authors.initials: PT
authors.lastname: Michie
authors.affiliation: School of Psychiatry, University of New South Wales, Sydney, New South Wales, Australia; Schizophrenia Research Unit, South Western Sydney Local Health District, Sydney, New South Wales, Australia.
authors.forename: Philip B
authors.initials: PB
authors.lastname: Ward
authors.affiliation: Centre for Translational Neuroscience and Mental Health, The University of Newcastle, Newcastle, New South Wales, Australia; Schizophrenia Research Institute, Darlinghurst, New South Wales, Australia; Hunter Medical Research Institute, Newcastle, New South Wales, Australia.
authors.forename: Paul E
authors.initials: PE
authors.lastname: Rasser
authors.affiliation: Centre for Translational Neuroscience and Mental Health, The University of Newcastle, Newcastle, New South Wales, Australia; Schizophrenia Research Institute, Darlinghurst, New South Wales, Australia; School of Psychology, The University of Newcastle, Newcastle, New South Wales, Australia.
authors.forename: Juanita
authors.initials: J
authors.lastname: Todd
authors.affiliation: Department of Psychology and York Neuroimaging Centre, University of York, Heslington, United Kingdom.
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Johnston
authors.affiliation: Schizophrenia Research Institute, Darlinghurst, New South Wales, Australia; Imaging Genetics Center, Institute for Neuroimaging and Informatics, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America; Departments of Neurology, Psychiatry, Radiology, Engineering, Pediatrics, and Ophthalmology, University of Southern California, Los Angeles, California, United States of America.
authors.forename: Paul M
authors.initials: PM
authors.lastname: Thompson
authors.affiliation: Centre for Translational Neuroscience and Mental Health, The University of Newcastle, Newcastle, New South Wales, Australia; Schizophrenia Research Institute, Darlinghurst, New South Wales, Australia; Hunter Medical Research Institute, Newcastle, New South Wales, Australia.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Schall
mesh_terms: D000328:Adult; D017668:Age of Onset; D001499:Bayes Theorem; D002908:Chronic Disease / Q000523:psychology; D005072:Evoked Potentials, Auditory; D005260:Female; D006801:Humans; D008297:Male; D008959:Models, Neurological; D012559:Schizophrenia / Q000453:epidemiology / Q000503:physiopathology*; D055815:Young Adult