Skip to main content
. Author manuscript; available in PMC: 2013 Sep 19.
Published in final edited form as: Annu Rev Cell Dev Biol. 2011 Jul 21;27:653–679. doi: 10.1146/annurev-cellbio-092910-154026

Figure 4.

Figure 4

The cerebrospinal fluid (CSF, blue) distributes diffusible factors during brain development. (a) IGF2 and other factors (purple spheres) are secreted by the choroid plexus and delivered by the CSF to targets on the apical ventricular surface of the developing cerebral cortex (Lehtinen et al. 2011). CSF and CSF-FGF2 have been shown to support proliferation of midbrain progenitor cells (Martin et al. 2006, 2009). Whether similar rules apply to CSF-borne retinoic acid, Wnt, and Bmp signaling, as well as other as yet uncharacterized signals, remains to be elucidated. (b) Sonic hedgehog (Shh) secreted by the hindbrain/fourth ventricle choroid plexus signals in an autocrine manner to instruct choroid plexus development. CSF-Shh also signals in a paracrine manner to stimulate the proliferation of cerebellar granule neuron precursors located in the external granule cell layer (Huang et al. 2009, 2010).