Brain growth occurs throughout embryogenesis and early postnatal life, but its foundation is laid in the primitive neuroepithelium. In this issue of Neuron, Sahara and O'Leary identify Fgf10 as a key regulator of the neuroepithelial to radial glial transition and subsequently of size of the rostral forebrain.
Phoenix, T. N., & Temple, S. (2009). Baby got brain: Fgf10 sets rostral cortical size. Neuron. https://doi.org/10.1016/j.neuron.2009.06.015