Yawning Does Something Unexpected in Your Brain, MRI Scans Reveal

Key Points:

• A University of New South Wales study using MRI scans found that yawning moves cerebrospinal fluid (CSF) away from the brain, unlike deep breaths which do not cause this effect, suggesting yawns have a unique physiological impact.
• Both yawning and deep breathing increase blood flow leaving the brain, allowing more fresh blood to enter, but only yawning causes a surge in carotid arterial blood flow into the brain by about a third during its initial stages.
• Each individual has a unique and consistent yawning pattern, akin to a fingerprint, indicating a personal central pattern generator controls how people yawn.
• Researchers speculate yawning might help clear waste from the brain or regulate brain temperature, which could have implications for understanding neurodegenerative diseases linked to waste accumulation in the central nervous system.
• Despite yawning’s widespread occurrence across species and its contagious nature, its exact purpose remains unclear, but this study suggests it plays a significant role in central nervous system homeostasis; findings were published in Respiratory Physiology & Neurobiology.