There was an error in Development (2016) 143, 4620-4630 (doi: 10.1242/dev.140681).

On page 11 of the supplementary information, an equation to calculate Tc was given incorrectly as Tc=Ts/(BrdU+/BrdU). The correct equation is Tc=Ts/(BrdU+/Radial Glia). The correct equation was used to calculate the Tc values presented in Figure 3E; therefore, this error does not affect the scientific conclusions of the paper.

The authors apologise to readers for this mistake.