Enriched Environment (EE) is a well-established paradigm for naturally increasing neural activity in vivo.Studies have shown that rearing adult rodents in enriched environments elicit changes throughout the brain,including the levels of various proteins,the extent of dendritic arborization and synapse strength of various neural circuits.Furthermore,rodents reared in EE have improved spatial learning compared to control animals reared in standard housing.However,most of the above mentioned research were performed using adult animals.Since different mechanisms of synaptic plasticity exist between early development and the adult stage,and the neural consequences of environmental enrichment in young animals is still largely unknown,we established an EE paradigm from birth.To conveniently mark hippocampus CA1 pyramidal neuron,we used a Thy-1 promoter driven GFP mouse.