Researchers have made a groundbreaking discovery regarding the blood flow in the brains of awake mice, challenging existing beliefs about how blood circulates in the brain. The study, supported by the National Institutes of Health (NIH), revealed a network of blood vessels that rhythmically expand and contract, causing ‘waves’ to sweep across the brain’s surface.
Unlike previous knowledge, which focused on the pulses of blood flow synchronized with the heartbeat, the researchers observed slower waves of blood flow changes occurring approximately every ten seconds. These waves accounted for up to 20% of the brain’s total blood supply and were minimally correlated with brain activity.
The visible bulges in the blood vessels created by these waves play a crucial role in mixing the fluid surrounding brain cells. This mixing activity facilitates the removal of waste products and other substances from the brain, a process essential for combating neurological disorders like Alzheimer’s disease.
The researchers speculate that the dilation and contraction of blood vessels, causing the waves, contribute more to fluid mixing than directional movement. This mechanism aids in transferring harmful components from the brain to the cerebrospinal fluid, particularly during sleep, serving as a protective mechanism against various neurological conditions.
Moreover, these findings have implications for interpreting functional magnetic resonance imaging (fMRI) scans, commonly used to monitor brain activity. The discovery that blood flow waves occur independently of brain activity introduces a new layer of complexity that researchers must consider when analyzing fMRI data.
The study sheds light on the intricate relationship between blood flow dynamics and brain function, offering valuable insights into potential therapeutic targets for neurodegenerative diseases. By unraveling the mysteries of brain blood flow, researchers aim to enhance our understanding of brain health and develop innovative treatments for neurological disorders.
