Imaging the Sleeping Brain’s ‘Rinse Cycle’ May Help Understand Alzheimer’s Disease

New research, published in the journal Science, has found that the ebb and flow of electrical activity and blood in the brain may trigger cleansing waves of cerebrospinal fluid (CSF).

Functional magnetic resonance imaging was used to monitor brain activity during non-rapid eye movement (REM) sleep in 13 healthy adults. The video shows an initial wave of bloodflow (red) accompanied by electrical activity (not visible), followed by an influx of CSF (blue).

Oscillating electrical activity contributes to memory consolidation, while CSF is thought to clear metabolic waste from the brain. It now appears that the two processes are linked, and could act as a ‘rinse cycle’ to remove harmful proteins. While this research looked at healthy adults, further study could explain why poor sleep is associated with memory loss in Alzheimer’s disease, a condition involving the toxic accumulation of amyloid and tau protein.