For example, recent results have shown that by up-regulating the BDNF/TrkB - mediated PI3K/Akt/mTOR signaling pathway, the expression of postsynaptic density 95 and synapsin in the hippocampus of MDD rats can be increased, and the depressive behaviors of the lipopolysaccharide (LPS) -induced MDD rat model can be improved (Wu et al., 2024). Here, NTRK2 is linked to major depressive disorder.