Optogenetics: The Future of Memory?

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Everyone has bad days they would rather forget. But what if it were possible to actually edit out our negative memories with a beam of light, and replace them with new information? Thanks to two neuroscientists at MIT, this might be a reality sooner, rather than later.

The first challenge in altering a memory is locating one, to begin with. Ideally, the researchers, Steve Ramirez and Xu Liu, aimed to be able to activate a memory, with the flip of a switch. Since memories are not exactly a tangible thing to identify, “locating” a memory is a bit tricky. Instead, Ramirez and Liu monitored which cells of the brain are active in the process of memory formation.

In the duo’s TED talk, they compare the active cells in creating a memory to the image of an office building at night. You can tell where people in the building are working based on where the lights are on. For brain cells, they too “light up” with different biological indicators to show that they are at work.

As noted in the video, biological sensors that are activated in memory making are similar to viewing a building at night. Where the lights are on, someone is working. For cells in the brain, they “light up” their own processes, as an indication of when they are actively working.

The researchers were able to identify which brain cells are active in the making of a fearful memory by seeing a mass of cells crystallize in one particular region, after providing a small shock to a lab mouse.

After such a memory is created, activating it again would need to be quick. Drugs take too long to move through the system, as the trigger would need to move within milliseconds. Electricity, while fast, is difficult to use in such a precise manner, not to mention how it would likely fry the brain.

Light, on the other hand, is fast. Not to mention the fact that brain cells are not typically affected by beams of light. Proving that truth can indeed be stranger than fiction, the two neuroscientists shot lasers into the beams of mice to alter their memories. Such is the study of Optogenetics.

Optogenetics is “a biological technique which involves the use of light to control cells in living tissue.” The researchers equipped mice with optogenetic channels, in the hippocampus. When new memories are formed, cells connected with the memory would become light sensitive.

To test this, the mouse was given a small shock in the foot, creating a fearful memory. After this occurred, the cells associated with the memory lit up. When mice are afraid, they will back into a corner, and “freeze” so that no part of their body moves, in fear of something dangerous happening. When the mouse with the newly formed fear was put into a new enclosure, the mouse showed no fear.

While in the enclosure where the shock did not take place, the mouse explored the enclosure, not at all fearful of its surroundings. The researchers then activated the light beam, causing the fearful cells to become active once more. Despite not receiving a shock in the second enclosure, the mouse froze as if it was put back in the original enclosure.

Liu joked that the edited memory was like a “remixed memory.” Where initially, they were simply doing the equivalent of pressing play on a memory, they were now able to edit the mouse’s perception of reality.

Liu and Ramirez published their findings in Nature and were met with many questions from the public on what this development can mean for us all. The ability to edit neurological information can be a huge advancement in the treatment of neurological disorders. Modifying memories could potentially help aid the treatment of a multitude of mental conditions and disorders. But, as many pointed out, modifying the memories of individuals could become a question of ethics, should it fall into the wrong hands. 

As mentioned by Ramirez, these findings open up a whole realm of possibilities for the future of how memories are researched. There are many questions to be asked and answered. Emerging fields, like optogenetics, are bridging the quickly shrinking gaps between photonics and neurobiology.  For more information on how lasers are being used to bridge the gaps between vastly different scientific sectors, please visit www.lia.org

About the Author
Steven Glover is a proud member of the LIA staff. When he is not at work he is actively involved in several charitable efforts.
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