“…Thus, there is neither a dominant site of water entry into the CSF in any of the animal species (wild-type, knockout mice for aquaporins AQP1 and AQP4 [34,35,41] ), nor in patients before or after plexectomy procedures [33] , nor in healthy volunteers or in those with idiopathic normal pressure hydrocephalus [48] . Faster (more dominant) arrival of water into the CSF was observed only in the case of a local osmolarity increase in one of the CSF compartments, which results in an increase in the CSF volume and pressure, leading to the dilation of ventricles [35,44,45] . Accordingly, the CSF volume is regulated by the correlation between hydrostatic and osmotic forces inside the blood and in the ISF/CSF compartment.…”