Id3 was rapidly upregulated in YFP+ stem cells in the SVZ 1 day after PT, while pharmacologic depletion of fibrinogen reduced Id3 expression in YFP+ stem cells in the SVZ compared to control animals after PT (Fig. 3f), suggesting that fibrinogen deposition in the SVZ stem cell environment after cortical brain injury rapidly upregulates Id3, which in turn promotes NSPC differentiation into astrocytes. The gene discussed is ID3; the disease is brain injury.