Rodents above all, but also zebrafish (Danio rerio) (Douglass et all, 2008), fruit flies (Drosophilia melanogaster) (Lima & Miesenböck, 2005), nematode worms ( Caenorlhabditis elegans) (Blaxter 20100) and non-human primates (Han et al., 2011). With a research tool as powerful as optogenetics, the next logical step is to produce it in humans for therapeutic effects on mental illnesses. Chow and Boyden recently published an article discussing the obstacles that would need to be overcome to bring optogenetics into clinical trials. The biggest problem is the use of viral vectors and the resulting immune response (Chow & Boyden, 2013). Human opsins, like rhodopsin in the human eye, could be installed in neurons, but these cells are slower than the microbial ones currently used for optogenetics. Gene therapy advances every day, and it is possible that one day humans may reap the benefits of the precision actions that optogenetics has to offer. While optogenetics remains purely a research tool and does not directly produce beneficial effects in our species, it has nevertheless offered humans an unprecedented glimpse into the function and dysfunction of the nervous system. Optogenetics has been adopted in laboratories around the world and has allowed scientists to increase or decrease the activity of unique brain areas on command. Through the use of this research tool and much more, in-depth insight has been gained