Synapse engineering: A new level of brain modulation.

Brain modulation is a powerful approach to study brain function in vivo. Tremendous progress had been made by controlling brain activity with different brain modulation tools. Synapse is the more fundamental functional unit of brain. In theory, synapse engineering could modulate brain function more precisely. However this had not been possible until recently. Our review provides a brief introduction of various brain modulation methods, and elaborates on a recently developed synapse-engineering tool. This technique allows modulation of specific synapses in vivo for the first time and has been used to clarify the causal role of synaptic plasticity in learning and memory. We also discuss its potentials for further development.