Magnetoencephalographic Microstates Reveal Disrupted Brain Activity Patterns in Schizophrenia Controlling for Treatment-Related Modulations.

BACKGROUND AND HYPOTHESIS: Electroencephalographic (EEG) or magnetoencephalographic (MEG) microstates, ie, discrete spatial configurations of brain signals over time, are thought to reflect the activity of large-scale brain circuits. Altered EEG microstates associated with cognitive control and attention have been consistently reported in schizophrenia (SCZ). However, EEG microstate characterization in other psychiatric disorders and treatment-related modulations are still unclear. MEG microstates (mMSs) have only recently been explored and despite source detection advantages have not been applied to characterize psychiatric disorders so far. Controlling for the impact of treatment, we expected altered mMSs corresponding to brain sources associated with cognitive dysfunction in SCZ.

STUDY

DESIGN

We studied mMSs in a large cohort of controls and patients with SCZ, bipolar disorder (BD), and major depressive disorder (MDD). First, we assessed treatment-related modulations and, after removing treatment bias, we explored anomalies in psychiatric disorders and possible associations with psychopathology.

STUDY

RESULTS

Benzodiazepine administration was associated with reduced mMS variance and duration, together with increased occurrence across diagnoses. After excluding patients receiving benzodiazepines, patients with SCZ showed increased contribution of occipito-parietal (mMS 1-2) and reduced fronto-temporal and centro-parietal (mMS 3-4) configurations relative to controls. Altered mMSs reflected impairments in brain generators linked to sensory processing and cognitive function. Analyses in BD and MDD, featuring smaller sample sizes, showed no significant differences from controls.

CONCLUSIONS

In summary, we detected mMSs disruptions in patients with SCZ, involving source brain regions associated with sensory integration and cognition. These effects did not depend on pharmacological treatment and were not significant in mood disorders.