Science is Fun Fridays!

 

A distinct layer of tissue has been discovered in the brain, and is one of four such membranes between the skull and the brain.

The meningeal layer consists of the dura, arachnoid, and pia mater membranes.  The latest addition divides the subarachnoid space, which contains cerebrospinal fluid (CSF).

It is called the subarachnoid lymphatic-like membrane and appears to separate clean CSF from dirty CSF that contains cells' waste products.

CSF surrounds the brain and spinal cord, acting as a shock absorber as well as providing immunological protection to the brain.  It also serves a vital function in the regulation of cerebral blood flow.

The SLYM was found to be packed with immune cells, which can use the membrane to surveil the CSF for signs of infection or inflammation.

Tears in the SLYM can lead to these cells entering the brain, possibly explaining prolonged inflammation following injury.  There may also be implications for Alzheimer's, as a rupture could explain prolonged suppression of glymphatic flow.

IFL Science