Implanting Fake Memories: A New Method to Treat Mental Disorders?

Direct activation of a group of neurons that is active during learning might elicit behavioural output of a specific memory.

In 2010, the British/American director Christopher Nolan introduced his iconic movie Inception, opening a new boundary for memory-manipulating theme that awed viewers around the world. Precedentedly, the cinematic universe also witnessed similar prime examples like Total Recall (1990) or The Bourne Identity (2002). Such cases inspired neuroscientists to explore pathways for memory manipulation, allowing patients to experience fake event flashbacks that did not happen to them. Will this eventually replace conventional methods to cure mental illness, such as depression?

Image: Justin Renteria

A 2012 study from a group of scientists of Massachusetts Institute of Technology (MIT), USA discovered a sufficient way to trigger long-term fear-related memory. By using optogenetic stimulation, or light-induced stimulation, of a hippocampal engram, fear memory recollection could be activated and controlled. This allows manipulating memory in various ways, including deletion, addition, activation and suppression of certain memories.

Optical stimulation of engram-bearing cells induces post-training freezing. Image: NCBI

The MIT researchers labelled a population of hippocampal dentate gyrus neurons in mice, which contribute to the formation of new episodic memories, then activated them during fear learning with channelrhodopsin-2 (ChR2). Later, they triggered those neurons again, but in a different context. The mice showed increasing freezing only when they were under light stimulation, suggesting that the light-induced fear memory recalled.

This freezing was not detected in non-fear-conditioned mice expressing ChR2 in a similar proportion of cells, nor in fear-conditioned mice with cells labelled by enhanced yellow fluorescent protein instead of ChR2. Finally, activation of cells labelled in a context not associated with fear did not evoke freezing in mice that were previously fear conditioned in a different context, suggesting that light-induced fear memory recall is context specific. (Liu et al., 2012)

In a recent TED Talk, Steve Ramirez, one of the leading neuroscientists in this experiment, says: “I see a world where we can reactivate any kind of memory that we’d like. I also see a world where we can erase unwanted memories.”

Image: Mind Control World CACH

This raises an ethical question whether manipulating memory could do more harm than good. Although this method is thought to be a potential way to cure mental disorders or phobias, people are concerned that it could be used negatively. For example, forcing people to confess something they did not actually do or voting for candidates they do not want.

Image: Hacking the Workplace

To answer this issue, Ramirez also states: “One group in our lab was able to find the brain cells that make up a fear memory and converted them into a pleasurable memory, just like that. That’s exactly what I meant about editing these kinds of processes.”

What do you think about this technology? Will this become a breakthrough in creating eternal happiness; or will this lead us to another Inception of illusional memories, only this time it is real?

To find out more about the experiment, you can watch this TED Talk below:

References:

Al-Ghaili, H. (2017, May 14). Implanting fake memories into your brain could treat depression. Retrieved August 30, 2017, from https://www.facebook.com/ScienceNaturePage/videos/1072682412864016

Liu, X., Ramirez, S., Pang, P. T., Puryear, C. B., Govindarajan, A., Deisseroth, K., & Tonegawa, S. (2012, March 22). Optogenetic stimulation of a hippocampal engram activates fear memory recall. Retrieved August 30, 2017, from https://www.ncbi.nlm.nih.gov/pubmed/22441246