Figure 3. Physostigmine reverses burst suppression during continuous inhalation of 2.0% isoflurane.
(A) A representative electroencephalogram recorded from a rat inhaling 2.0% isoflurane, with time=0 indicating the beginning of physostigmine (0.2 mg/kg IV) injection. The electroencephalogram changed from a burst suppression pattern to a new rhythm without isoelectric (suppression) periods after physostigmine administration. (B) A spectrogram computed from the same animal in (A) shows that physostigmine increased δ, θ and α power. (C) Power spectral densities computed from burst periods 2-minutes pre- and post-physostigmine, and their 95% confidence intervals (with Bonferroni correction), were constructed around the mean spectra across all rats (n = 6). Power at higher frequencies was reduced after the administration of physostigmine.