Lights! Camera! Action Potentials?
Remember when the lights at a concert excited you? Well, neurons can relate to that as well now that we have optogenetics!
Imagine a world where brain control is possible. Well, now you won’t have to imagine it because brain control is becoming a possibility, and it’s coming fast!
But wait! Isn’t that against the conduct of science? Well, yes, and no. It involves a long surgical process so human “experiments” would have to consent to it first, of course.
It seems pretty scary. But, it’s nothing close to the voodoo magic you see in books or movies. Rather, scientists will use this technology for a good cause. By good cause, I mean figuring out ways around brain diseases and how our brain controls our behavior.
With optogenetics, scientists gain an even better understanding of how brain diseases work and how we can cure these diseases.
So, what exactly is optogenetics?
Optogenetics is the method of using light to control genetically modified neurons to convert light into electricity. In other words, optogenetics is a combination of the principles of optics and genetics.
Woah. Let’s break that down a little.
First, let’s go over what neurons are. Neurons are cells in the nervous system and the brain. They send and receive signals from your brain to your muscles by signaling each other. They send signals (AKA action potentials) to each other using electricity. This then contributes to a certain behavior being carried out by the nervous system.
Optics is the study of the properties and behavior of light. Genetics, in this case, refers to the study of the manipulation of gene expression. Manipulating genes within optogenetics is extremely important because we can’t magically manipulate our neurons without introducing light-sensitive proteins called rhodopsins into biological tissues.
An example of rhodopsin is channelrhodopsin. Channelrhodopsin is derived from algae and is a microbial photosensitive protein. This means it can absorb blue-green light to open the neural ion channels of neurons. We activate channelrhodopsin through a blue-green light to allow ions in. These neural ion channels then accept H+, Na+, K+, and Ca+ ions, causing action potentials through the rapid depolarization of the plasma membrane.
If we can scale down the study of the brain to individual neurons, our understanding of the brain will increase exponentially. Using optogenetics, we can better understand how neurons communicate with each other. By understanding how they communicate, we can also understand how diseases prevent communication between neurons.
For example, if someone has a stroke, optogenetics will help scientists understand what triggered the stroke by having a detailed, mapped out structure of the brain.
To see how neurons communicate with optogenetics, a light would turn on some neurons, and then scientists can record the behavior of the connected ions.
Scientists performed a study on mice on the effects of strokes on the brain. It is well known that strokes cause neurons in the affected area to die, causing problems for that area and the areas connected to it. But, what damage would minor strokes cause? That’s why we need optogenetics to track strokes on a smaller scale.
By using channelrhodopsin, otherwise known as ChR2, scientists can draw a map of a brain before and after a stroke. Scientists were able to determine the detrimental effects of small strokes on the brain by investigating how the maps changed over time after an induced stroke. After 1 week, activity was very low overall, and the small stroke even affected an area far away from the induced stroke. After 8 weeks, activity levels rose but were still not at normal levels. With the data collected, scientists concluded that even small strokes can have detrimental effects on the brain. The data collected can also aid scientists in discovering effective ways to treat a stroke because of their deeper understanding of strokes.
Optogenetics is also ideal for treating cancer because it can be used as a less harmful alternative to drug therapy. Since cancerous cells in the nervous system(neurons) can form brain tumors, optogenetics may the solution to reverting these cells to a normal state. Neurons being in a normal state means that it is non-dividing. This is the ideal state because it allows neurons to communicate with each other.
If neurons divide at an abnormal rate, a tumor can form. The rapid division of cells can cause cell death or cell cycle arrest. So, we want neurons to stay in a non-dividing state. In other words, manipulating neurons into staying in a non-dividing state will prevent, or even cure, brain tumors.
The possibilities with optogenetics don’t stop there. As optogenetics continues to improve, our understanding of brain diseases continues to improve as well. Although the use of optogenetics is limited to animals now, the use of optogenetics for humans may be revolutionary. We can achieve even more precise mappings of the human brain, and more precisive treatments to brain diseases will form as well. Although other methods can map and understand the brain, optogenetics takes the top seat for targeting specific parts of the brain.