EEG microstates associated with salience and frontoparietal networks in frontotemporal dementia, schizophrenia and Alzheimer’s disease

ObjectiveThere are relevant links between resting-state fMRI networks, EEG microstate classes and psychopathological alterations in mental disorders associated with frontal lobe dysfunction. We hypothesized that a certain microstate class, labeled C and correlated with the salience network, was impaired early in frontotemporal dementia (FTD), and that microstate class D, correlated with the frontoparietal network, was impaired in schizophrenia.MethodsWe measured resting EEG microstate parameters in patients with mild FTD (n = 18), schizophrenia (n = 20), mild Alzheimer’s disease (AD; n = 19) and age-matched controls (old n = 19, young n = 18) to investigate neuronal dynamics at the whole-brain level.ResultsThe duration of class C was significantly shorter in FTD than in controls and AD, and the duration of class D was significantly shorter in schizophrenia than in controls, FTD and AD. Transition analysis showed a reversed sequence of activation of classes C and D in FTD and schizophrenia patients compared with that in controls, with controls preferring transitions from C to D, and patients preferring D to C.ConclusionThe duration and sequence of EEG microstates reflect specific aberrations of frontal lobe functions in FTD and schizophrenia.SignificanceThis study highlights the importance of subsecond brain dynamics for understanding of psychiatric disorders.

► We investigated EEG microstates related to resting-state networks in various mental disorders.
► Decreased durations of microstate maps are associated with the deficits of resting-state networks.
► Aberrant sequences of microstate maps can explain the impairment of insular-cingulate (salience) network.