title: The interplay of lorazepam-induced brain oscillations: microstructural electromagnetic study.
abstract: OBJECTIVE
  The effects on cortical rhythms of a single-dose (30 microg/kg) administration of the GABAA agonist lorazepam were examined in a randomized, double-blind, cross-over, placebo-controlled study with 8 healthy volunteers using simultaneous electroencephalography (EEG) and magnetoencephalography (MEG).
  
  
  METHODS
  The oscillations were assessed by means of adaptive classification of short-term spectral patterns.
  
  
  RESULTS
  Lorazepam (a) decreased the percentage of EEG/MEG segments with fast-theta, delta-alpha, fast-theta-alpha and alpha activity and increased percentage of EEG/MEG segments with delta, delta-slow-theta, delta-beta, slow-theta and polyrhythmic activity; (b) decreased diversity of EEG/MEG signals (in terms of spectral patterns) and increased the general instability of the signal; (c) increased stabilization periods of the spectral patterns (reduced brain information processing); (d) maintained larger maximum periods of temporal stabilization for delta, slow-theta, delta-slow-theta, delta-beta and polyrhythmic activity (in terms of spectral patterns); (e) did not increase power in the independent beta rhythm.
  
  
  CONCLUSIONS
  Lorazepam caused significant reorganization of the EEG/MEG microstructure. These results suggest also that adaptive classification analysis of single short-term spectral patterns may provide additional information to conventional spectral analyses.
authors.affiliation: BM-Science Brain & Mind Technologies Research Centre, Espoo, Finland. alexander.fingelkurts@bm-science.com
authors.forename: Alexander A
authors.initials: AA
authors.lastname: Fingelkurts
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Fingelkurts
authors.forename: Reetta
authors.initials: R
authors.lastname: Kivisaari
authors.forename: Eero
authors.initials: E
authors.lastname: Pekkonen
authors.forename: Risto J
authors.initials: RJ
authors.lastname: Ilmoniemi
authors.forename: Seppo
authors.initials: S
authors.lastname: Kähkönen
mesh_terms: D000328:Adult; D001611:Beta Rhythm; D001921:Brain / Q000187:drug effects* / Q000502:physiology*; D018592:Cross-Over Studies; D003700:Delta Rhythm; D004311:Double-Blind Method; D004569:Electroencephalography; D005260:Female; D018755:GABA Agonists / Q000494:pharmacology*; D006801:Humans; D008140:Lorazepam / Q000494:pharmacology*; D015225:Magnetoencephalography; D008297:Male; D012016:Reference Values; D013826:Theta Rhythm
chemical_list: D018755:GABA Agonists; D008140:Lorazepam