Ann Arbor Times

Researchers at the University of Michigan have proposed a new theory that may explain the universal sleep pattern observed across species. Led by Sara Aton and Michal Zochowski, the study suggests that non-REM and REM sleep stages play sequential and complementary roles in memory consolidation.

According to Aton, "Evolutionarily, it’s so preserved and so ubiquitous across species. That means there’s probably something really important about that particular order of sleep." The researchers posit that during non-REM sleep, memories are strengthened, while REM sleep prunes them to keep them distinct.

The team conducted experiments on mice to observe brain activity during different phases of sleep following conditioning scenarios. These observations were supplemented with computer modeling developed by Zochowski's group. The model simulates neuronal activity changes influenced by acetylcholine levels during various sleep stages.

Zochowski noted the practical implications for humans: "Let’s say you have three meetings in a day. We know that you’ll remember these meetings better after a good night’s sleep."

The research is published in PLoS Computational Biology and supported by the National Science Foundation, Chan Zuckerberg Initiative, and National Institutes of Health. While promising, Aton emphasized that their findings are preliminary: "What we have now is a study that says, ‘Look, this is what could be happening.' Now we have to prove that the model is associated with reality."