Activation of TRKB is a critical mediator of activity-dependent synaptic plasticity (Park and Poo, 2013), and the AD-induced TRKB signaling reactivates a state of juvenile-like plasticity in the adult brain, which has been suggested to underlie the effects of ADs on mood (Castrén and Antila, 2017; Karpova et al., 2011; Maya Vetencourt et al., 2008). The gene discussed is NTRK2; the disease is Alzheimer disease.