Awakenings and interviews
There were 76 successful awakenings and interviews obtained in Experiment 1 (Experiment 1: awakenings and interviews, and achieved states, with mean measured drug plasma concentrations for those participants who achieved the state. ∗Four dexmedetomidine and four propofol experiments were terminated before UR3. R, responsiveness; In Experiment 1, we noted discrepancies between the participants' answers to the brief dream question and the full interview, but we used only the full interviews (with detailed content reports) in the analyses. Of note, five times (6.6%) the participants answered ‘yes’ to the brief dream question but in the full interview no longer recalled any content. Further, nine times (11.8%) the participants stated in the brief dream question that they were ‘unsure’ but reported dreaming in the full interview. Relatedly, 15 times (19.7%) the participants answered ‘no’ to the brief dream question but in the full interview reported experiences categorised as memory incorporation.In Experiment 2, 36 out of the 37 participants fell asleep at least once but successful PET scans, and subsequent interviews were achieved with 32 participants. Notably, in Experiment 2, the same participant could be interviewed more than once from the same sleep stage.