One contribution of 17 to a Theo Murphy meeting issue 'Unity and diversity of cilia in locomotion and transport'.The brain ventricles are interconnected, elaborate cavities that traverse the brain. They are filled with cerebrospinal fluid (CSF) that is, to a large part, produced by the choroid plexus, a secretory epithelium that reaches into the ventricles. CSF is rich in cytokines, growth factors and extracellular vesicles that glide along the walls of ventricles, powered by bundles of motile cilia that coat the ventricular wall. We review the cellular and biochemical properties of the ventral part of the third ventricle that is surrounded by the hypothalamus. In particular, we consider the recently discovered intricate network of cilia-driven flows that characterize this ventricle and discuss the potential physiological significance of this flow for the directional transport of CSF signals to cellular targets located either within the third ventricle or in the adjacent hypothalamic brain parenchyma. Cilia-driven streams of signalling molecules offer an exciting perspective on how fluid-borne signals are dynamically transmitted in the brain.This article is part of the Theo Murphy meeting issue 'Unity and diversity of cilia in locomotion and transport'.

v Moreover, liposome attachment was shown to depend on the lipid composition used for liposome preparation. These results indicate, that cargo and target site specific interaction is needed in addition to site specific delivery of the cargo by the CLN.Following these results, exosomes secreted from Z310 rat choroid plexus cells were isolated from cell culture supernatant, characterized, fluorescently-labelled and applied to the cilia-generated near wall flow of v3V. The results suggest, that exosomes are transported along the CLN similarly to liposomes. Further experiments are needed to clarify the transport and interaction of exosomes within the CLN in detail. vi Contents List of Figures xi Symbols and Abbreviations xiii 4 Discussion 894.1 Transport of extracellular vesicle like cargo in cilia-generated flow of the v3V .