Researchers led by Masako Tamaki at the RIKEN Center for Brain Science in Japan report a link between deep sleep and cerebrospinal fluid, the clear liquid that surrounds and supports the brain and spinal cord. Published in Proceedings of the National Academy of Sciences, the study demonstrates how changes in cerebrospinal fluid signals during sleep—as measured by MRI—are time-locked to slow brain waves and other neural events.
These findings offer a clue as to why stable sleep is important for normal brain function, particularly within the brain network that controls learning and memory.
Why do we sleep? Scientists think that sleep is important for consolidating memories and removing waste from the brain that accumulates as a result of brain activity while we are awake.