Fig. 2.

Summary of experimental protocol. Anaesthetic induction was performed following routine practice, with sevoflurane and nitrous oxide. A laryngeal mask airway (LMA) was then inserted and the end-tidal (ET) concentration of sevoflurane was set to 2.5% and nitrous oxide <5%. Following electrode placement, the experimental protocol was carried out, with 2 blocks of experimental stimuli followed by cannulation. The 5-second period before (red) and after (blue) each stimulus were analysed and 3 background periods were taken throughout the recording.