Neuronal dynamics direct cerebrospinal fluid perfusion and brain clearance 2024 Jiang-Xie et al

Abstract

The accumulation of metabolic waste is a leading cause of numerous neurological disorders, yet we still have only limited knowledge of how the brain performs self-cleansing. Here we demonstrate that neural networks synchronize individual action potentials to create large-amplitude, rhythmic and self-perpetuating ionic waves in the interstitial fluid of the brain. These waves are a plausible mechanism to explain the correlated potentiation of the glymphatic flow1,2 through the brain parenchyma. Chemogenetic flattening of these high-energy ionic waves largely impeded cerebrospinal fluid infiltration into and clearance of molecules from the brain parenchyma. Notably, synthesized waves generated through transcranial optogenetic stimulation substantially potentiated cerebrospinal fluid-to-interstitial fluid perfusion. Our study demonstrates that neurons serve as master organizers for brain clearance. This fundamental principle introduces a new theoretical framework for the functioning of macroscopic brain waves.

Paywall, https://www.nature.com/articles/s41586-024-07108-6

 

Study Suggests During Sleep, Neural Process Helps Clear the Brain of Damaging Waste

We’ve long known that sleep is a restorative process necessary for good health. Research has also shown that the accumulation of waste products in the brain is a leading cause of numerous neurological disorders, including Alzheimer’s and Parkinson’s diseases. What hasn’t been clear is how the healthy brain “self-cleans,” or flushes out that detrimental waste.

But a new study by a research team supported in part by NIH suggests that a neural process that happens while we sleep helps cleanse the brain, leading us to wake up feeling rested and restored. Better understanding this process could one day lead to methods that help people function well on less sleep. It could also help researchers find potential ways to delay or prevent neurological diseases related to accumulated waste products in the brain.

The findings, reported in Nature, show that, during sleep, neural networks in the brain act like an array of miniature pumps, producing large and rhythmic waves through synchronous bursts of activity that propel fluids through brain tissue. Much like the process of washing dishes, where you use a rhythmic motion of varying speeds and intensity to clear off debris, this process that takes place during sleep clears accumulated metabolic waste products out.

https://directorsblog.nih.gov/2024/...cess-helps-clear-the-brain-of-damaging-waste/

 

I suspect this is yet another high profile piece of pseudoscience.

I am not aware of any brain diseases being due to accumulation of metabolic waste. Metabolic waste normally is cleared by venules, not lymphatics. It is hard to see which direction synchronised neuronal ion shifts could usefully impel fluid. And they seem to have got CSF and interstitial back to front. I could go on...

the things you are liable to read in the Bible...

 

I've posted an open-access paper for background at Waste Clearance in the Brain (2021, Frontiers in Neuroanatomy) —

 

Some quotes from this paper's intro —

Rhythmic ionic waves in ISF boost brain perfusion —

 

Sleep synchronizes neurons to drive brain CSF perfusion —

Chemogenetic inhibition impairs brain clearance —

Synthesized waves enhance CSF-to-ISF perfusion —

 

Discussion —