Cilia coordinated temporal-spatial flow in the mammalian brain*

The walls of the ventricular system of mammalian brain are lined with ependymal cells, each of which sprouts a bundle of cilia that constantly beat and thereby maintain directional cerebrospinal fluid (CSF) flow. A transport network driven by coordinated motile cilia inside the ventral third ventricle (v3V) was reported recently. This network contains several CSF flow streams, generates flow patterns such as separatrix and whirl, and may coordinate the delivery of CSF components to different target sites within the ventricle. Particle tracking showed that in mouse brain this flow network locally differs between the two sides of the v3V and changes with age, which implies an age-dependent complex delivery system for CSF constituents. We also studied numerically the contribution of the temporal-spatial flow pattern to the overall CSF flow within the 3D ventricular cavity, and uncover likely physiological consequences of the flow pattern.