Figure 1.

Glymphatic system and blood-brain barrier (BBB). Cerebrospinal fluid (CSF) flows into the brain from subarachnoid and cisternal spaces through periarterial spaces (Virchow spaces). CSF exchanges with interstitial fluid are facilitated by aquaporin-4 (Red dots) located on the end-foot processes of perivascular astrocyte. The CSF motion into the brain pushes the convective streaming of interstitial fluid and interstitial solute (IS) (Black dots) through the extracellular space to perivenous spaces. Perivenous fluid and solutes then drain from the brain mainly along the large-caliber ventral veins. Inset: major proteic components of tight junctions.