animal, showing that motor patterns in the roundworm C. elegans could be evoked by light stimulation of genetically selected neural circuits (published in December 2005). In mice, controlled expression of optogenetic tools is often achieved with cell-type-specific Cre/loxP methods developed for neuroscience by Joe Z. Tsien back in the 1990s to activate or inhibit specific brain regions and cell-types in vivo.

In 2007, the labs of Boyden and Deisseroth