Hippocampus is well-known as the center of spatial navigation and learning. Prof. Häusser and his team have recently published a very exciting article about direct modification of spatial navigation memories via holographical optogenetic stimulation. They applied virtual reality to train the animals for certain tasks and used two-photon deep imaging to visualize the place cell ensembles. They claimed stimulation of only a dozen unique place cell could be enough changing the behavior of the animal. This is the first direct evidence for a casual role of in place cell in navigation. This is a huge step to understand the memory encoding of the hippocampus. Congratulations for the authors!
Graphical abstract of the experimental design and results: