Fig 3.

(a) Representative 30-s EEG recording from an aged rat inhaling 1.5% isoflurane, showing a burst suppression pattern. Bursts are highlighted in blue and suppressions are in black. (b) Representative 30-s EEG recording from a young adult rat inhaling 1.5% isoflurane. This animal was not in burst suppression, indicating a lighter depth of anaesthesia. (c) Burst suppression probability (BSP) for 10 min of EEG data at 3.0, 2.5, 2.0, and 1.5% isoflurane. At 2.0% isoflurane, aged rats mainly exhibited a burst suppression pattern, whereas young adult rats did not. One aged rat was still in burst suppression at 1.5% isoflurane.