NTRK2 and neurodegenerative disease: TrkB-FL has been linked to neuroprotective effects after CNS insults by excitotoxicity, amyloid-β, and the HIV protein gp120 (Almeida et al., 2005; Nosheny et al., 2005; Kitiyanant et al., 2012) and changes in TrkB-FL are associated with neurodegenerative diseases (Longo et al., 2007; Zuccato and Cattaneo, 2009).