SPACE-ORIENTED EEG SEGMENTATION REVEALS CHANGES IN BRAIN ELECTRIC-FIELD MAPS UNDER THE INFLUENCE OF A NOOTROPIC DRUG

Map landscape-based segmentation of the sequences of momentary potenti al distribution maps (42-channel recordings) into brain microstates du ring spontaneous brain activity was used to study brain electric field spatial effects of single doses of piracetam (2.9, 4.8, and 9.6 g Noo tropil((R)) UCB and placebo) in a double-blind study of five normal yo ung volunteers. Four 15-second epochs were analyzed from each subject and drug condition. The most prominent class of microstates (covering 49%, of the time) consisted of potential maps with a generally anterio r-posterior field orientation. The map orientation of this microstate class showed an increasing clockwise deviation from the placebo condit ion with increasing drug doses (Fisher's probability product, p<0.014) . The results of this study suggest the use of microstate segmentation analysis for the assessment of central effects of medication in spont aneous multichannel electroencephalographic data, as a complementary a pproach to frequency-domain analysis.