An inwards breath drives the flow of fluid that bathes the human brain.

Cerebrospinal fluid cushions the brain, flushes out waste and in rodents seems to be controlled by pulsating blood flow. To find out how the fluid is regulated in humans, Steffi Dreha-Kulaczewski at the University Medical Center Göttingen in Germany and her colleagues used real-time magnetic resonance imaging to scan the brains of ten healthy volunteers while they did breathing exercises. The researchers found that an intake of breath had a stronger effect on fluid flow than the heartbeat did.

The approach could be used to study disorders that result in disruptions to the flow of cerebrospinal fluid.

J. Neuro. 35, 2485–2491 (2015)