Highlights
• This is a broad perspective, historical review of the relationships between REM and NREM sleep.
• Deep insights into of the most relevant and competing concepts.
• Features a new “asymmetrical†hypothesis on the distal end of ultradian cycles.
• REM sleep potentially viewed as an evolutionary remnant of ectotherms sleep.
https://www.sciencedirect.com/science/article/abs/pii/S1389945720300757