Optogenetics, The Knight In Shining Neurons

So excited for this!

In 15 days, Marvel’s Moon Knight will be released and I couldn’t be more excited. Ever since the trailer, I’ve been counting down the days until the release of this psychological thriller. From the cinematography to the soundtrack, Moon Knight seems to be one of the darker Marvel shows — and I’m here for it. However, the point I am most excited about is the depiction of Moon Knight’s struggles in managing dissociative identity disorder (DID).

What often drew me to the Moon Knight comics were the varying depictions of mental illness. In a world where an estimated 264 million people are affected by depression alone, being able to understand the multitude of mental illnesses a person could have was important to me. Moreover, it raised a concern. As mental health issues continue to rise, the rush to understand each of them individually has not. At the moment, we still lack in understanding exactly what causes certain issues and how best to treat them.

Or, at least that’s what I thought.

Introducing Optogenetics

Optogenetics is the idea of taking neurons, cells in our brain that send electrical signals and changing their genetic code to make them light-sensitive. From there, scientists are able to use light in order to control brain activity.

Utilizing genetic engineering which edits the genetic code of living organisms through deleting or adding information, scientists are able to insert a new piece of code into neurons. This new code tells the neurons to create opsins, a group of proteins that is light-sensitive. Now, when light shines onto these neurons, electrical current will form in the cells — helping to direct the movement of charged ions across the cell membrane in response to light. In neuroscience, many use an opsin known as channelrhodopsin-2 (ChR2) which is found in green algae and is sensitive to blue light.

Here is a picture of the opsins. The yellow one is channelrhodopsin-2 from algae!

Now, there are multiple ways of inserting opsins into the neurons. It depends on what exactly you want to control. Using certain techniques, one can insert opsin into the genetic code of all neurons. However, with more advanced techniques, one can target a specific type of neuron or a specific location in the brain.

With the neurons now light-sensitive, scientists will use selective stimulation which allows them to choose which neurons travel down the pathways as they send signals. This allows them to better understand what specific neurons affect.

There are many benefits to this! On one hand, by stimulating an area of the brain, scientists can study how one area affects another. If one area of the brain is damaged, they will be able to better determine what behaviours it will elicit in response. On the other hand, using light with some neurons can help scientists see how it affects other areas. Not only will they be able to see how and when neurons communicate with each other, but this also provides more insight into diseases that negatively affect communication between neurons (e.g. stroke).

A stroke affects the brain.

So, How Is It Being Used Today?

Today, optogenetics is primarily used to treat diseases and at the very least, alleviate symptoms. And though primarily used in the neuroscience field, it has been increasingly applied to other areas like stem cells and cardiac tissues.

Here are a couple specific use cases:

• Parkinson’s disease: Optogenetic experiments have helped us better understand neurodegenerative diseases. With this disease, in particular, deep brain stimulations, where electrode implants are turned on and off through light sensitivity, can help relieve symptoms.
• Depression: In one study, optogenetics was used to target the areas of the brain (like the VTA region) that could help scientists understand how to develop better treatments for depression. This marked a big improvement from antidepressants, which are deemed ineffective for about 30–40% of depressed patients.
• Blindness: In cases where the retinal cells have sustained damage, optogenetics help restore vision to a certain degree. In this study,, a blind man was able to improve his eyesight by genetically engineering the neurons in his retina to produce opsin. This allowed the signals in the eye to travel through the optic nerve into the visual processing centre of the brain, replacing the photoreceptors that he lost due to his blindness.

Here are some common symptoms of Parkinson’s disease.

Aside from disease treatment, some optogenetics experiments are more focused on answering questions related to the mind. These include studying what makes people hungry, fearful, anxious, etc. It also helps us understand which specific neurons aid in learning, memorization, etc.

Now, What’s In Store For The Future?

Optogenetics is still a relatively new field with new discoveries being made every year! If experiments continue to be conducted, I believe optogenetics could stem to solve even more global issues. In particular, optogenetics could be used to better understand complex mental health illnesses so that more effective treatments can be developed.

Dissociative identity disorder or DID is a mental health illness where a person feels themselves literally shut off as they distance themselves from a violent or traumatic experience. In many cases, continuous emotional and/or physical abuse can lead to the development of DID, with almost 3 out of every 4 individuals entering a dissociative state because of it. The most common symptom of this is when a patient begins to form 2+ distinct identities/personalities. Aside from this, DID is heavily associated with other illnesses like depression and post-traumatic stress disorder (PTSD).

With 1.5% of the global population formerly diagnosed with DID, treatments consist of antidepressant consumption and forms of psychotherapy which are common mental health treatments. At the moment, it is difficult to figure out what specific triggers lead the brain to dissociation. However, utilizing optogenetics could help scientists better understand which areas of the brain and specific neurons lead a person to dissociate.

DID was formerly known as Multiple Personality Disorder.

In 2020, a Standard study found that a specific cluster of neurons in the brain utilized a particular protein which aided in the trigger of dissociation. This research alone could help scientists create more effective therapies for DID. Moreover, due to the similarities between DID and PTSD, these targeted neurons could lead to even more findings related to PTSD.

The Knight In Shining Genetically-Modified, Light-Sensitive Neurons

All in all, optogenetics has the potential to change the game for all types of diseases! By utilizing a combination of genetic engineering and light sensitivity, optogenetics is able to connect the dots between a patient’s symptoms and the neurons that trigger this response. From applying it to neurodegenerative diseases like Parkinson’s to emotional responses of the mind like fear, optogenetics can unearth the mysteries of the brain.

Just as Moon Knight saves innocent civilians in peril, optogenetics can save innocent patients in pain.

Thank You!

Thank you for reading my article! If you have any questions or would like to chat, feel free to send me an email which you can find in the about section or comment down below.

If you would like to learn more about optogenetics, I’ve put some resources below!

Optogenetics Relieves Depression in a Mouse Trial

What Is Optogenetics and How Can We Use It to Discover More About the Brain?

Why optogenetics deserves the hype