Will Atkinson, Managing Editor | December 25, 2024

Historically, neuroscientists yearning to determine the function of specific brain regions would create a lesion, or an incision within the brain, thus rendering that region non-functional. From there, these scientists would assess the changes in behavior of their test subject. Any change after the surgery would be considered a consequence of the inactivity of the targeted brain region, which would allow them to form hypotheses about that region’s usual function. Due to a number of other limitations, these brain lesions were long considered the only way to confidently assess causality within the brain.

Within recent years, however, scientists have turned their attention in a different direction: towards algae. Scientists have begun repurposing a protein predominantly found in algae called channelrhodopsin, a type of ion channel. Like the cells within the retinae of our eyes, channelrhodopsin is an opsin, or light sensitive protein. This means that it can stimulate a cascade of activity when stimulated by light. In order to introduce this protein to the test subject, it is common for viral injections to be administered during surgery to target specific brain regions and cell types. From there, a laser or any other light source can activate the specific cells that are affected by the virus and thus contain the channelrhodopsin. This procedure is part of a growing field called optogenetics.

Optogenetics represents the future of causal manipulations within neuroscience. Instead of requiring highly invasive and damaging measures, optogenetics allows scientists to safely stimulate specific brain regions with high spatial and temporal resolution. Additionally, this innovative intervention poses potential therapeutic benefits, as it grants clinicians with a mechanism to control which parts of the brain are active. With optogenetics, the future of neuroscience is light!

References 

Emiliani, V., Entcheva, E., Hedrich, R., & Others. (2022). Optogenetics for light control of biological systems. Nature Reviews Methods Primers, 2(55). https://doi.org/10.1038/s43586-022-00136-4

ScienceDirect. (2023). Channelrhodopsin. Retrieved December 8, 2024, from https://www.sciencedirect.com/topics/medicine-and-dentistry/channelrhodopsin

ScienceDirect. (2023). Lesion studies. Retrieved December 8, 2024, from https://www.sciencedirect.com/topics/neuroscience/lesion-studies#:~:text=Studying%20the%20effects%20of%20brain,–22%5D%2C%20and%20more