Flunitrazepam effects on human sleep EEG spectra II: Sigma and beta alterations during NREM sleep

Sunao Uchida*, Nobuyuki Okudaira, Kyoko Nishihara, Yoshinobu Iguchi, Xin Tan

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


Flunitrazepam (FNZ) is known to enhance the higher EEG frequencies, including sigma (10-15 Hz) and beta (20-28 Hz). Both sigma and beta frequency bands show an inverse relationship with delta (0.3-3 Hz) during NREM periods, as we have previously reported. It is not known whether generation of these two EEG frequencies is mediated by the same or different neuronal mechanisms. In this report, we compare alterations of delta, sigma and beta EEG induced by FNZ (4 mg) orally administered to five healthy male subjects for seven consecutive nights. Sleep EEG on the baseline night (BLN), and the fourth and seventh drug nights (4DN, 7DN) was subjected to fast Fourier transform (FFT) analysis. On drug nights, sigma was enhanced without regard to delta amount, but beta was enhanced only during epochs containing low delta. Thus, sigma and beta EEG were altered differently by the same pharmacological agent. These results suggest that sigma and beta EEG are mediated by different neuronal mechanisms.

Original languageEnglish
JournalLife Sciences
Issue number9
Publication statusPublished - 1996 Jul 26
Externally publishedYes


  • benzodiazepine
  • computer analysis
  • delta
  • neurophysiology
  • sigma beta
  • sleep EEG

ASJC Scopus subject areas

  • Pharmacology


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