AAV9, adeno-associated viral serotype 9; AKT, protein kinase B; AMPAR, α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor; ANOVA, analysis of variance; BDNF, brain-derived neurotrophic factor; BDNF­TrkB signaling; CMC-Na, carboxymethyl cellulose sodium; CREB, cAMP response element-binding protein; CUMS, chronic unpredictable mild stress; CaMKII, Ca2+/calmodulin-dependent protein kinase II; DG, dentate gyrus; Depression; ERK1/2, extracellular regulatory protein kinase; FST, forced swimming test; GAP-43, growth-associated protein 43; GSK-3ß, glycogen synthase kinase-3ß; Ginsenoside Rb1; GluR1, AMPAR subunit glutamate receptor 1; HFS, high-frequency stimulation; IACUC, Institutional Animal Care and Use Committee; ICR, Institute of Cancer Research; LIMK1, LIM-kinase 1; LTD, long-term depression; LTP, long-term potentiation; MAP-2, microtubule-associated protein-2; MAPK, mitogen-activated protein kinase; MDD, major depressive disorder; NMDAR, N-methyl-D-aspartic acid receptor; NR2A, NMDAR subunit 2A; NR2B, NMDAR subunit 2B; NeuN, neuronal nuclei; OFT, open field test; PI3K, phosphatidylinositol 3-kinase; PSD, postsynaptic density; PSD-95, postsynaptic density protein 95; Rb1, ginsenoside Rb1; SEM, standard error of the mean; SPT, sucrose preference test; Syn, synaptophysin; Synaptic plasticity; TST, tail suspension test; TrkB, tropomyosin-related kinase B; fEPSPs, field excitatory postsynaptic potentials; i.g., intragastrically; miR-134; miR-134, miRNA-134; miRNAs, microRNAs; qRT-PCR, quantitative real-time PCR