11.   The growing professional literature on sleep paralysis has often mentioned the parallels with reports of alien abductions.

12.   Those who believe in alien abductions deny that sleep paralysis could be behind it all.

13.   What is going on in the brain during sleep paralysis is unclear.

14.   What is striking is that although the symptoms of sleep paralysis are generally very similar, the images in the hallucinations and the interpretation of them seem to vary.