MET and Mental deterioration: We recently found that in Met conditional knockout (cKO, Metfx/fx:emx1cre) mice, there was a disruption in hippocampus LTP and an early cognitive decline (Ma et al., 2019); conversely, in transgenic mice overexpressing Met, cortical excitatory neurons exhibit altered synaptic proteins and the timing of critical period plasticity (Chen et al., 2020).