title: Reduced high and low frequency gamma synchronization in patients with chronic schizophrenia.
abstract: Schizophrenia has been conceptualized by dysfunctional cognition and behavior related to abnormalities in neural circuitry. The functioning of the neural circuitry can be assessed using the auditory steady state response (ASSR). Moreover, in recent years, research on high (>60 Hz) gamma band oscillations has become of increasing interest. The current study used whole-head, 306-channel magnetoencephalography (MEG) and investigated low and high gamma band oscillations with the ASSR. The subjects comprised 17 patients with schizophrenia and 22 controls. The current study investigated the MEG-ASSR elicited by click trains of 20-, 30-, 40- and 80-Hz frequencies, and symptom-ASSR associations in patients with schizophrenia. The mean power, phase-locking factor, dipole moments and source locations of the ASSR were estimated. The main findings were: (1) patients with schizophrenia showed bilaterally reduced ASSR power and dipole moments specific to the 40-Hz and 80-Hz frequencies; (2) patients with schizophrenia showed less right-greater-than-left 40-Hz ASSR power and phase-locking factor compared with healthy subjects, indicating that schizophrenics may be characterized by an abnormal asymmetry of the 40-Hz ASSR; (3) increased severity of global hallucinatory experiences was significantly associated with smaller left 80-Hz MEG-ASSR in patients with schizophrenia. The current study highlights the high and low frequency gamma abnormalities and provides clear evidence that schizophrenia is characterized by abnormalities in neural circuitry.
authors.affiliation: Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Rikako
authors.initials: R
authors.lastname: Tsuchimoto
authors.forename: Shigenobu
authors.initials: S
authors.lastname: Kanba
authors.forename: Shogo
authors.initials: S
authors.lastname: Hirano
authors.forename: Naoya
authors.initials: N
authors.lastname: Oribe
authors.forename: Takefumi
authors.initials: T
authors.lastname: Ueno
authors.forename: Yoji
authors.initials: Y
authors.lastname: Hirano
authors.forename: Itta
authors.initials: I
authors.lastname: Nakamura
authors.forename: Yuko
authors.initials: Y
authors.lastname: Oda
authors.forename: Tomofumi
authors.initials: T
authors.lastname: Miura
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Onitsuka
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D000704:Analysis of Variance; D001303:Auditory Cortex / Q000503:physiopathology*; D001931:Brain Mapping; D002908:Chronic Disease; D003344:Cortical Synchronization / Q000502:physiology*; D004569:Electroencephalography; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D015225:Magnetoencephalography; D008297:Male; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales; D011571:Psychoacoustics; D012559:Schizophrenia / Q000473:pathology* / Q000503:physiopathology*; D013997:Time Factors; D058067:Wavelet Analysis; D055815:Young Adult