Rapid Eye Movements and Brain Heat

Rapid, random eye movements during sleep are probably related to increased temperature in eye-connected parts of the brain, or the speed and randomness of the molecules making it up.

Odilon Redon’s “Eye Balloon.” Photo from WikiArt. Public domain.

While for over 50 years, it was thought
that only mammals and birds have these distinct
neurological sleep stages, exciting new research has
shown that reptiles, fish, drosophila, octopus, and other invertebrates also display sleep states with analogous features.

— Jaggard et al., “Non-REM and REM/Paradoxical Sleep Dynamics
Across Phylogeny” (2021)

Contents

∘ Brain Temperature Cycles and REM
∘ Universality
∘ Works Cited

Brain Temperature Cycles and REM

The animal brain cycles through a range of temperatures over various time periods. It gets slightly warmer and therefore more fluid, dynamic, disorderly and expansive as we wake up and go about the day, then cools down and becomes relatively solid, static, orderly and compact again when we go to sleep. The brain also heats up repeatedly throughout the night, during dreaming, random, rapid eye movement or REM…