The major mechanism of TrkB‐FL downregulation in excitotoxicity is cleavage by calpain (Tejeda et al, 2016), ubiquitous protease central to neuronal death in stroke, and excitotoxicity‐associated neurodegenerative diseases (Bevers & Neumar, 2008). This evidence concerns the gene NTRK2 and neurodegenerative disease.