Light-Sensitive Neurons: The Evolution of Brain Study

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Francis Crick articulated that in order to better understand the brain, scientists would need to be able to control specific types of cells or individual neurons (Crick, 1979). He stated that if this was possible, researchers could activate a single neuron and watch the cascade of other neurons being activated. Or inhibit a neuron and observe what other cells around it followed. Crick continues and believed that this would someday be possible. His knowledge of the visual system, a system of the brain that responds to light, must of led to his thoughts that we could create neurons that express a sensitivity to light in every division of the brain. It is now possible to control specific cell types with high temporal and spatial precision in …show more content…

Shining blue light (473 nm wavelength photons) on these cells, in vitro, would cause them to send a nerve impulse 1-2 milliseconds later. Once the light was turned back off, the cells returned to normalcy. In their resting state, a electrical potential exists between the interior of the cell and outside. When ChR2 was activated, its channel would open and cause an influx of positive ions to increase the internal negative charge. This is a similar process to what is occurring all over the brain during every emotion, action, and sensory input we …show more content…

Rodents mostly, 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 logical next step is producing it in humans for therapeutic effects on mental illnesses. Chow and Boyden recently published an article with discussion about the obstacles that would have to be overcome to bring optogenetics to clinical trials. The largest issue is the use of viral vectors and the subsequent immune response (Chow & Boyden, 2013). Human opsins, such as rhodopsin in the human eye, could be installed into neurons but these cells are slower than the microbial ones currently in use for optogenetics. Gene therapy is advancing everyday and it is possible that some day humans could reap the benefits of the precision actions optogenetics has to offer. Even if optogenetics remains as purely a research tool and does not give rise to beneficial effects directly in our species, it has still offered humans an unparalleled look into the function and dysfunction of the nervous system. Optogenetics has been adopted in laboratories around the world and enabled scientists to increase or decrease the activity of exclusive brain expanses on command. Great insight has been obtained through the use of this research tool and a great deal more

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