What is Optogenetics?

MBM Trainee Jennie Gardner gives an overview of optogenetics and how it can allow us to learn about the brain. Transcript: Hi everyone! My name is Jennie Gardner and today I’m going to talk about a technique called optogenetics and explain how it can allow us to learn about the brain.   So, to start with, what is optogenetics?   Well, the word optogenetics can be broken down into two main parts: opto (which refers to the use of optics or light in this case) and genetics (which refers to the use of genetic engineering for this technique).   So, altogether, optogenetics is a technique that brings together the use of both light and genetic engineering, and this technique can allow scientists to selectively control neurons in the brain.   Or, to be more specific, optogenetics utilizes genetically manipulated cells in the brain which, when exposed to certain wavelengths of light, express these light-responsive fluorescent proteins, which indicate neural activity.   To put this all into perspective, let me give you an example of how I have used optogenetics in the lab.   So, there is a well-known phenomenon is science in which, when a mouse engages in strenuous physical activity, usually in the form of running on a running-wheel, the neurons in a specific brain region called the hippocampus become highly activated. And this is true during and throughout the whole time that the mouse is running on the wheel.   And it’s important to note that, when the mouse is not running on the wheel, these neurons do not express this elevated level of activation.   So, in order to understand why this exercise-induced brain activation occurs in these mice, I wanted to test whether we could activate those same neurons (that are typically activated during physical activity) but without having the mice actually run on the wheels.   And I was able to use optogenetics to test this!   In this case, I used genetically engineered mice whose neurons would respond to red wavelengths of light and allow us to then measure the neural activation that resulted from the light exposure.   And it worked!   The red light did increase neural activation in the hippocampus, just like it does during wheel running!   Now, this is just one example of how optogenetics can be used in science, but all-in-all, optogenetics is an incredibly useful tool that can allow us to discover how neurons connect and work together during different types of activities.   And this allows us to further our overall understanding of how the brain works! This video was supported by the National Science Foundation under grant 1735252. https://minibrain.beckman.illinois.edu/