In early stages of development, the laminated structure of cerebral cortex is organized by proliferative, morphogenetic, and migratory processes. In these stages, cells within the ependymal lining of neural tube are thought to secrete embryonic cerebrospinal fluid (eCSF). As the neural tube closes, the choroid plexuses (CPs) secrete proteins such as growth factors, cytokines and morphogenes into the eCSF. The apical neuroepithelium is bathed with this fluid which plays regulatory roles in cortical cell proliferation, differentiation, and maintenance. Because of the eCSF protein contents and their impacts on neurogenesis, we focused on the effect of eCSF growth factors and their changes during brain development. Bibliographic databases including PubMed, Scopus and Google Scholar were searched between years 1990 to 2013 for the keywords "Cerebrospinal fluid" and "Neurogenesis". In the first step, 200 articles were found, after elimination of duplicates or irrelevant papers 49 papers were selected and reviewed.

Embryonic cerebrospinal fluid (E-CSF) contains many neurotrophic and growth factors, acts as a growth medium for cortical progenitors, and can modulate proliferation and differentiation of neural stem cells. Mesenchymal stem cells (MSCs) are multipotential stem cells that can differentiate into several types of mesenchymal cells as well as nonmesenchymal cells, such as neural cells. In the present study, the effect of E-CSF on proliferation and neural differentiation of bone marrow mesenchymal stem cells (BM-MSCs) was investigated to test whether E-CSF is capable of driving these cells down the neuronal line. To verify the multipotential characteristics of BM-MSCs, the cells were analyzed for their osteogenic and adipogenic potential. Expression of the neural markers, MAP-2 and β-III tubulin, was determined by Immunocytochemistry. BM-MSCs differentiate into neuronal cell types when exposed to b-FGF. BMMSCs cells cultured in medium supplemented with CSF showed significantly elevated proliferation relative to control cells in media alone. E-CSF (E17-E19