Optogenetics: Becoming Attuned to the Brain

When I first learned about optogenetics approximately a week ago, my first thought was how unnerving this supposed mind-control seemed. I didn’t and still don’t believe our society is entirely ready for that. However, I was severely mistaken and now understand the truly phenomenal potential this technology holds in understanding why our brains work the way they do, and how it is game-changing in the way we approach the study and treatment of neurological disorders.

Upon completing my research, I was immediately reminded of one thing. Every year at Christmas, my father and I were challenged with the most aggravating, hair-pulling of tasks, getting every light on our Christmas tree to light up. My mother would often say that it was pointless, we’d only have to fix them again next year. But when it comes to an engineer and his stubborn, like-minded daughter, there is always a solution, even if it means staying up till two in the morning every year. Why not fix what can be fixed?


We would sit on the floor and my father would plug up one of the sets of Christmas lights. “The best way to determine where the problem is is to make it visible,” he would tell me as we would examine a section of the lights that remained dark. “They are all connected, a system, so the failure of one light creates a chain of dysfunctional lights.” After checking the functioning of each of the metal nubs on the Christmas lights and making sure they were secure, we would always find the one light that didn't work, and it was easy to replace it or add a missing piece.


Similarly, optogenetics is a way of monitoring neural pathways and the transfer of signals by “shining a light” on neurons. We can track how electrical signals flow through a network and find the areas where this is disrupted. This is especially useful in identifying neurological disorders.


So then, is that all we can do with optogenetics? Is there more to this field than just controlling a few brain cells? Considering where we are now, are there issues we wish to improve? Possible new uses of this technology? In this article, I explore the highly underestimated field of optogenetics and the potential it holds in revolutionizing our relationship with the brain.


This article is sectioned into three main topics:

1. The Workings and Understanding of Optogenetics

2. Applications of Optogenetics in Research

3. Promising Opportunities for the Future Utilization of Optogenetics


The Working and Understanding of Optogenetics

Optogenetics is the usage of genetic engineering to enhance neurons with photosensitive proteins. These enhanced neurons can then be stimulated using light to generate action potential and the firing of a neuron or neurons. Scientists can use optogenetics to control specific neural activities and track the pathways of neurons.

The channel rhodopsin gene (ChR), found in green algae Chlamydomonas reinhardtii and its two encoded forms- channel rhodopsin 1 (ChR1) and channel rhodopsin 2 (ChR2) are both used to generate ion channels that are activated by high-intensity light. The shining of the most common form of this high intensity light, blue light, over specific neurons causes the opening of the ion channels in the neurons. This creates the effect of depolarization and induces action potential. The neurons fire and an electrical signal is sent out along the network of neurons, transporting the signal between a vast system within the brain.

Figure 1. The activation of ion channels (Credit: Wikipedia)

When viewing the communication between neurons, scientists have the ability to observe how neurons are able to communicate with each other. Disruption in neuronal communication can also be indicative of neurological diseases such as Parkinson's disease, providing greater insight into how these diseases affect the brain.

Application of Optogenetics in Research

As of now, research in optogenetics has mainly consisted of understanding neurological disorders and disentangling the neural circuits of the brain.

A study conducted by Stanford University used optogenetics to stimulate neurons in the brains of stroke mics. In this experiment, mice were given 1 minute of optogenetic stimulation 15 days after having a stroke. Divided into groups, non-stimulant stroke mice (the control) and stimulant stroke mice (the experimental group), this experiment demonstrated promising results in the ability of optogenetics for the rehabilitation of stroke patients. At the end of the experiment, the stroke mice who received the stimulant showed increased cerebral blood flow and neurovascular response.

Figure 2. The results of an optogenetic stimulant experiment on the increased neural activity of post-stroke mice (Credit: The Stanford Steinberg Lab)

Optogenetics is also being utilized to understand the neural circuitry of the brain and its role in the bodily functions of animals. A variety of studies have been conducted using mice to test the activation and deactivation of certain neural circuitries in areas of the brain and how they impact actions in the body. One study was able to activate and deactivate motor circuitry in the brains of several mice using optogenetics. The experimenters were able to control when the mice moved and stopped moving, simply by shining a light onto the brains. This research has massively changed our knowledge of how certain areas of the brain affect different parts of the body and even the body as a whole. Some scientists believe this could be useful in combatting some of the greatest crises plaguing our world such as the ongoing battle of addiction when it comes to opioids and alcohol.

Figure 3. A recipient of stimulant in an experiment to determine the abilities of optogenetics in controlling motor functions of the body (Credit: The New York Times)


Promising Opportunities for the Future Utilization of Optogenetics

While studies in optogenetics have primarily focused on how neural transmission works and enabling the improvement of the communication between neurons some scientists believe this lucrative method of studying the brain has other uses when it comes to controlling the functioning of a cell.

Cardiac professionals believe that optogenetics could potentially be used to control the activities of the heart and diminish heart irregularities. For conditions associated with the heart like arrhythmia, optogenetics could be implemented to manage the excitability of cells in the heart. The full development of this usage of optogenetic therapy could mean ground-breaking treatment for patients with cardiac disorders.

the study of optogenetics has primarily consisted of in vitro methods with limited in vivo applications. The preliminary method of genetically engineering neurons through surgical implantation is both a risky operation and can damage neural fibers and tissues in the brain. Now, scientists have proposed new ideas to use non-invasive deep brain stimulation. This would prevent the risk of harming test subjects and make the use of optogenetics safer for humans. Soon this technology could allow for optogenetics to be used in the management and recovery of those suffering from medical conditions.

While we haven’t even begun to scratch the surface of optogenetics, it is without a doubt that some of the biggest concerns of our current times could be solved with the continued exploration of optogenetics. Though we may not know where or how far this technology will take us, we can be sure that millions of lives will be changed by the power of optogenetics.

Thank you for taking the time to learn more about this amazing technology!


Resources:

med.stanford.edu/steinberg-lab/research/optogenetics.html

ncbi.nlm.nih.gov/pmc/articles/PMC3543095/#:~:text=Optogenetics%20allows%20for%20pathway%2Dspecific,%2C%20lesioning%2C%20and%20pharmacological%20manipulations

frontiersin.org/articles/10.3389/fbioe.2019.00466/full#:~:text=Optogenetics%20is%20an%20elegant%20approach,system%20and%20genetic%20engineering%20technologies.


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