What if light could be used to control cells to make us erase bad memories? This is not a utopia but a reality, at least in rats!
Optogenetics is a new fascinating technique that enables researchers to stimulate cells with light, thereby allowing for the direct control of behavior. The term optogenetic has been coined only in 2006, but since then has intrigued researchers worldwide, me included.
A recent seminal study, carried out at the University of California, has shown that optogenetics may be used to deactivate and then reactivate memories in the brains of genetically engineered rats.
In the experiment, the researchers optically stimulated a group of neurons in rats’ brains while also administering electric shocks. The rats learned to link the pain caused by the shocks with that optical, memory-forming, stimulation at high-frequency. Consequently, the rats exhibited fear behavior when it occurred again.
The amazing thing is that, by using low-frequency optical pulses, the rats “forgot” about the negative association between light pulses and electric shocks. What was even more impressive is that, using again memory-forming, high-frequency optical pulses to re-stimulate the same nerves that were originally tested, the rats were able to reactivate those lost memories.
In a nutshell, the rats were triggered to have fear, then to forget about the fear, then to have fear again and so on.
When I first read this discovery, I recalled immediately the analogy with one of my favorite movies, the eternal sunshine of the spotless mind by Michel Gondry, in which a couple have each other erased from their memories.
Will erasing fears, pain, negative emotions of all kind be the future application of optgenetics in humans? Will psychotherapists lose their jobs?