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-pre injection 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' EEC microstates and with results
using estimates of EEC 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.
