Microstate Segmentation of Spontaneous Multichannel EEG Map Series under Diazepam and Sulpiride

Abstract

Spontaneous multichannel brain electric field (EEG) map series of 20 seconds duration at 1, 15, 30, 45, and 60 minutes after the injection of a single dose of diazepam (13 ss) or sulpiride (6 ss) were segmented into microstates of quasi-constant landscape but varying durations. Post-minus-preinjection difference values were computed for the six microstate variables: specific window size, duration, orientation, distance between windows, and location of center of gravity on the anterior-posterior and left-right axis. Differences between drugs were explored with ANOVAs. Microstate duration increased after sulpiride, and the location of the microstate center of gravity on the anterior-posterior axis moved to a more anterior position after diazepam. The results are in agreement with expectations based on measurements of patients' EEG microstates and with results using estimates of EEG model source locations in the frequency domain. Microstate segmentation appears to be a useful method for physiologically meaningful reduction of multichannel brain electric field data in psychopharmacology.

EEG microstates as a tool for studying the temporal dynamics of whole-brain neuronal networks: A review

“…In the present review, we focus on those studies that used k-mean cluster analysis to determine the number of microstates and those that fixed the number of states to the canonical four maps. Earlier studies using different approaches for analysis (Dierks et al, 1997;Kinoshita et al, 1995;Strik et al, 1997;Strik et al, 1995) are not listed. The most prominent pathology studied using this approach is schizophrenia.…”

Increased Omega Complexity and Decreased Microstate Duration in Nonmedicated Schizophrenic Patients

“…In addition, the observed microstate configurations were concentrated in a few classes of field configurations which can be identified by spatial clustering [22,23] . Microstates have been studied for human information processing in healthy subjects [24,25] . Abnormal patterns of microstates have been reported in patients with dementia of the Alzheimer type who are characterized by cognitive impairments [26] .…”

Prestimulus EEG microstates influence visual event-related potential microstates in field maps with 47 channels

“…This approach implies a virtually unlimited time resolution (time-sample-bytime-sample decisions) and is therefore most appropriate for studies on brain information processing because these latter operations occur in the millisecond to sub-second range. Several studies on spontaneous Wackermann et al, 1993;Kinoshita et al, 1995) as well as event-related data (Lehmann and Skrandies, 1980;Brandeis et al, 1995;Koenig and Lehmann, 1996) showed that the field configuration changes in a clearly discontinuous way within a sub-second time range: brief epochs of quasi-stable field topography are concatenated by rapid changes of the spatial configuration. Algorithms that parse the sequences of momentary field maps into time segments of stable topography reduce these map series into sequences of microstates.…”