Subarachnoid lymphatic-like membrane

The SLYM is reported to be a thin monolayer of cells and contains its own immune cells. The SLYM may inhibit larger molecules, such as peptides and proteins, from passing into the interior of the brain and could thus assume a barrier function. == Discovery and interpretation==

SLYM was first reported as a possible novel anatomical structure in the human brain. SLYM is impermeable to any molecule larger than 3,000 daltons. This was further probed by in vivo MRI and fresh dissection. Only in vivo studies of brain fluid transport can reveal the dynamics of cerebrospinal fluid transport and its barriers. Pietilä et al., 2023 also described the existence of a Prox1+ cell layer located within the arachnoid beneath and separate from E-cadherin+ arachnoid barrier cells. == References ==