Fig. 4.
Spectrograms during emergence from anesthesia. Spectrograms were computed from cessation of isoflurane anesthesia to 3 min after electroencephalography (EEG) wake (black vertical line). Warmer colors (i.e., red) indicate higher power at a given frequency, while cooler colors (i.e., blue) indicate lower power at a given frequency. Data are shown for a representative animal treated with saline (SAL) or flumazenil (FLZ). (A) Cortical lead. (B) Hippocampal lead. Before EEG wake, there is a predominance of power in low (less than 4 Hz) frequencies with less power in higher frequencies. After EEG wake, power decreases in low frequencies and begins to appear in higher frequencies.