SFOCatCh is a light-gated cation channel that can be used as an optogenetic tool to activate neurons. It is an engineered derivative of ChR2, containing mutations to increase the off kinetics (C128S and D156A) and the L132C mutation to increase conductance of divalent cations (FBrf0238058). SFOCatCh behaves as a bistable channelrhodopsin (PMID:19079251); it is activated by a brief pulse of blue light (470nm) to produce a prolonged photocurrent with a longer duration than the initiating pulse, resulting in a stable step in membrane potential, and it can be inactivated by a second light pulse of longer wavelength (540nm) (FBrf0238058).