Interestingly, MEC17 knockout in the pyramidal cells did not affect the density of mushroom‐shaped mature dendritic spines (Figure 3D,E; p > 0.05) but aggravated the injury to dendritic spines after stroke compared with the MCAO + Thy1 CreERT2‐eYFP group (Figure 3D,E; p < 0.01). The gene discussed is THY1; the disease is Stroke.