PT  - JOURNAL ARTICLE
AU  - Marina Krylova
AU  - Sarah Alizadeh
AU  - Igor Izyurov
AU  - Vanessa Teckentrup
AU  - Catie Chang
AU  - Johan van der Meer
AU  - Michael Erb
AU  - Nils Kroemer
AU  - Thomas Koenig
AU  - Martin Walter
AU  - Hamidreza Jamalabadi
TI  - Evidence for modulation of EEG microstate sequence by vigilance level
AID  - 10.1101/2020.02.26.966150
DP  - 2020 Jan 01
TA  - bioRxiv
PG  - 2020.02.26.966150
4099  - http://biorxiv.org/content/early/2020/02/27/2020.02.26.966150.short
4100  - http://biorxiv.org/content/early/2020/02/27/2020.02.26.966150.full
AB  - The momentary global functional state of the brain is reflected in its electric field configuration and cluster analytical approaches have consistently shown four configurations, referred to as EEG microstate classes A to D. Changes in microstate parameters are associated with a number of neuropsychiatric disorders, task performance, and mental state establishing their relevance for cognition. However, the common practice to use eye-closed resting state data to assess the temporal dynamics of microstate parameters might induce systematic confounds related to vigilance levels. Here, we studied the dynamics of microstate parameters in two independent data sets and showed that the parameters of microstates are strongly associated with vigilance level assessed both by EEG power analysis and fMRI global signal. We found that the duration and contribution of microstate class C, as well as transition probabilities towards microstate class C were positively associated with vigilance, whereas the sign was reversed for microstate classes A and B. Furthermore, in looking for the origins of the correspondence between microstates and vigilance level, we found Granger-causal effects of vigilance levels on microstate sequence parameters. Collectively, our findings suggest that duration and occurrence of microstates have a different origin and possibly reflect different physiological processes. Finally, our findings indicate the need for taking vigilance levels into consideration in resting-sate EEG investigations.