This document discusses using optogenetics to manipulate hippocampal neurons and create false memories in mice. Researchers labeled neurons in mice when they explored a safe room. They then placed the mice in a new room where they received foot shocks while activating the previously labeled neurons from the safe room. When returned to the safe room, the mice exhibited fearful behaviors like freezing, showing a false memory of fear was created in the normally safe room. This demonstrates the ability to artificially manipulate neuronal pathways related to memory formation and suggests future potential for human applications.