title: Impaired P600 in neuroleptic naive patients with first-episode schizophrenia.
abstract: Deficits of working memory (WM) are recognized as an important pathological feature in schizophrenia. Since the P600 component of event related potentials has been hypothesized that represents aspects of second-pass parsing processes of information processing, and is related to WM, the present study focuses on P600 elicited during a WM test in drug-naive first-episode schizophrenics (FES) compared to healthy controls. We examined 16 drug-naive first-episode schizophrenic patients and 23 healthy controls matched for age and sex. Compared with controls schizophrenic patients showed reduced P600 amplitude on left temporoparietal region and increased P600 amplitude on left occipital region. With regard to the latency, the patients exhibited significantly prolongation on right temporoparietal region. The obtained pattern of differences classified correctly 89.20% of patients. Memory performance of patients was also significantly impaired relative to controls. Our results suggest that second-pass parsing process of information processing, as indexed by P600, elicited during a WM test, is impaired in FES. Moreover, these findings lend support to the view that the auditory WM in schizophrenia involves or affects a circuitry including temporoparietal and occipital brain areas.
authors.affiliation: Department of Psychiatry, Eginition Hospital, 74 Vas. Sophias Ave., Athens 11528, Greece.
authors.forename: C
authors.initials: C
authors.lastname: Papageorgiou
authors.forename: V P
authors.initials: VP
authors.lastname: Kontaxakis
authors.forename: B J
authors.initials: BJ
authors.lastname: Havaki-Kontaxaki
authors.forename: S
authors.initials: S
authors.lastname: Stamouli
authors.forename: C
authors.initials: C
authors.lastname: Vasios
authors.forename: P
authors.initials: P
authors.lastname: Asvestas
authors.forename: G K
authors.initials: GK
authors.lastname: Matsopoulos
authors.forename: E
authors.initials: E
authors.lastname: Kontopantelis
authors.forename: A
authors.initials: A
authors.lastname: Rabavilas
authors.forename: N
authors.initials: N
authors.lastname: Uzunoglu
authors.forename: G N
authors.initials: GN
authors.lastname: Christodoulou
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D017668:Age of Onset; D014150:Antipsychotic Agents / Q000494:pharmacology*; D002540:Cerebral Cortex / Q000473:pathology / Q000503:physiopathology*; D002908:Chronic Disease; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006760:Hospitalization; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D008570:Memory, Short-Term / Q000502:physiology*; D009483:Neuropsychological Tests; D011237:Predictive Value of Tests; D011930:Reaction Time / Q000502:physiology*; D012559:Schizophrenia / Q000150:complications* / Q000473:pathology / Q000503:physiopathology; D016008:Statistical Distributions
chemical_list: D014150:Antipsychotic Agents