In their recent study, Zheng et al. (1) concluded that Notch1 and Notch2 are not expressed in pyramidal neurons in the postnatal mouse forebrain. This conclusion was based upon an inability to detect expression changes in vivo after presumptive deletion using their CaMKII-Cre line (2, 3). Unfortunately, the authors provided no direct evidence that they efficiently deleted Notch1 or Notch2 in...
