When cerebral ischemia and hypoxia, the homeostasis of the body's internal and external environment, such as energy metabolism disorder, the accumulation of reactive oxygen species, the pathological increase of glutamate, not only cause the changes of synaptic morphology and neurotransmitters, but also affect the function of PSD95 integrated synaptic signal, the point-to-point transmission between synaptic contacts and the formation of LTP, which eventually leads to the decline of learning and memory ability21,22. The gene discussed is DLG4; the disease is Cerebral ischemia.