title: Psychopathology and working memory-induced activation of the prefrontal cortex in schizophrenia-like psychosis of epilepsy: Evidence from magnetoencephalography.
abstract: OBJECTIVE
  The aim of this study was to investigate whether magnetoencephalographic oscillations underlying working memory dysfunction in the dorsolateral prefrontal cortex (DLPFC) are related to psychopathological disturbance in patients with schizophrenia-like psychosis of epilepsy (SLPE).
  
  
  METHODS
  Twelve patients with SLPE and 14 non-psychotic epilepsy controls participated in this study. Magnetoencephalography was recorded while patients performed a visual working memory (WM) task. Psychopathology was assessed using a four-factor structure of the Brief Psychiatric Rating Scale, and regression analyses were carried out to examine the relative impact of severity of psychopathology on WM-induced activation of the DLPFC.
  
  
  RESULTS
  We found that activation of the WM-compromising DLPFC, as indicated by increased alpha desynchronization in patients with SLPE compared with their non-psychotic counterparts, showed a positive linear correlation with disorganization symptom scores. This association remained significant after controlling for confounding factors, including age, task performance, IQ, and duration of psychosis.
  
  
  CONCLUSIONS
  Our results indicate that abnormal activation in prefrontal areas engaged during working memory may be critical to domains of psychopathology, in particular disorganized thought-processing in patients with SLPE.
authors.affiliation: Department of Psychiatry and Clinical Neuroscience, Osaka University Graduate School of Medicine, Osaka, Japan.
authors.forename: Leonides
authors.initials: L
authors.lastname: Canuet
authors.forename: Ryouhei
authors.initials: R
authors.lastname: Ishii
authors.forename: Masao
authors.initials: M
authors.lastname: Iwase
authors.forename: Koji
authors.initials: K
authors.lastname: Ikezawa
authors.forename: Ryu
authors.initials: R
authors.lastname: Kurimoto
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Takahashi
authors.forename: Antonio
authors.initials: A
authors.lastname: Currais
authors.forename: Michiyo
authors.initials: M
authors.lastname: Azechi
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Aoki
authors.forename: Takayuki
authors.initials: T
authors.lastname: Nakahachi
authors.forename: Salvador
authors.initials: S
authors.lastname: Soriano
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Takeda
mesh_terms: D000328:Adult; D001931:Brain Mapping / Q000379:methods; D058256:Brain Waves / Q000502:physiology; D004827:Epilepsy / Q000150:complications / Q000503:physiopathology*; D005260:Female; D006801:Humans; D015225:Magnetoencephalography / Q000379:methods*; D008297:Male; D008569:Memory Disorders / Q000150:complications / Q000503:physiopathology*; D010775:Photic Stimulation; D017397:Prefrontal Cortex / Q000503:physiopathology*; D011597:Psychomotor Performance / Q000502:physiology; D011618:Psychotic Disorders / Q000150:complications / Q000503:physiopathology*