Data from: Origin and role of the cerebrospinal fluid bidirectional flow in the central canal

The circulation of cerebrospinal fluid (CSF) plays pivotal roles for body
axis formation and brain development. During embryogenesis, CSF is rich in
particles and proteins and flows bidirectionally in the central canal. The
origins of bidirectional flow and its impact on development are unknown.
Experiments combined with modeling and simulations demonstrate that the
bidirectionality of CSF flow is generated locally by caudally-polarized
motile cilia confined to the ventral wall of the central canal. Such
active bidirectional flow of the CSF accelerates the long-range transport
of particles propagating rostrally and caudally. In addition, spontaneous
muscle contractions increase local CSF flow and consequently enhance
long-range transport of extracellular lipidic particles. Focal ablation of
the channel connecting brain ventricles to the central canal reduces
embryo length, indicating that long-range transport contributes to
embryonic growth. Our study also demonstrates that at this early stage,
motile cilia ensure the proper formation of the central canal.