Hippocampus is an essential brain region for memory formation. While many analyses for hippocampus synaptic response in vitro have been reported, mechanism of memory formation in vivo is poorly understood. If we could inactivate synaptic function to induce "artificial memory erasure" in vivo, it should be strong strategy for functional mapping of synapses or decoding of brain information in living animals. Among many molecules in synaptic function, AMPA type glutamate receptor, GluA1 is especially known as important molecules for memory formation that is transported into synapses in response to many types of learning and experience (Takahashi et al. Science 2003, Rumpel et al. Science 2005. Mitsushima et al PNAS 2011 etc.). For development of "artificial memory erasure" technology, we are now trying to develop a new technique for inactivation of synaptic GluA1 receptors in vivo with light irradiation. Because this technology can be used in combination with in vivo live imaging, we hope to make a functional mapping of synaptic connectivity in living animals. In this session, we will report detail properties, specificity and validity in vitro and in vivo. Finally, we will also hope to discuss a future of this technology.