Evidence for dysregulated high-frequency oscillations during sensory processing in medication-naïve, first episode schizophrenia

Schizophr Res. 2013 Nov;150(2-3):519-25. doi: 10.1016/j.schres.2013.08.023. Epub 2013 Sep 7.


Introduction: High-frequency oscillations are important for sensory processing and dysfunctions in the amplitude and synchrony of beta- and gamma-band oscillations have been demonstrated in schizophrenia (ScZ). However, the presence of aberrant high-frequency oscillations in first-episode (FE), medication-naive patients during sensory processing is unclear.

Methods: Magnetoencephalographic (MEG) data were recorded from 15 never-medicated, FE-ScZ patients and 20 matched healthy controls during the perception of Mooney faces. MEG data were analysed for spectral power and single-sensor phase-locking in the beta (13-25Hz) and gamma- (25-140Hz) frequency range.

Results: FE-ScZ patients were characterized by significantly impaired sensory processing as indicated by a reduced discrimination index (A'). Impaired behavioural performance in ScZ-patients was accompanied by decreased spectral power in the high- (60-120Hz) gamma-band range. In contrast, oscillations in the lower (25-60Hz) gamma-band were largely intact and beta-band oscillations were increased. Analysis of cross-frequency coupling showed a reduced correlation between 60 and 120Hz amplitude values and beta-band power in FE-ScZ-patients relative to controls.

Discussion: Our findings show that impaired sensory processing in medication-naive, FE-schizophrenia is related to a dysregulation of neural oscillations which involves both an impairment in the generation of high gamma-band activity as well as a failure to downregulate task-irrelevant beta-band activity. Because of the interrelationship of these dysfunctions and the role of inhibitory networks in the shaping of high-frequency activity, aberrant neural oscillations in FE-schizophrenia may be linked to dysfunctions in the excitation-inhibition (E/I)-balance.

Keywords: First-episode; High-frequency oscillations; MEG; Neural synchrony; Perceptual organization; Schizophrenia.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Analysis of Variance
  • Brain Mapping*
  • Case-Control Studies
  • Cortical Synchronization / physiology*
  • Electroencephalography
  • Female
  • Fourier Analysis
  • Humans
  • Magnetoencephalography
  • Male
  • Pattern Recognition, Visual / physiology*
  • Perceptual Disorders / etiology*
  • Photic Stimulation
  • Schizophrenia / complications*
  • Young Adult