If you could have the memory of an event changed so that the outcome you remember in the future was different, would you? What if that memory was the cause of an addiction? This sounds like the plot of a number of movies but it’s now reality as scientists have manipulated the memories of mice to break them of their cocaine habits. What kind of person gets mice hooked on coke anyway?
According to their study published in Nature Neuroscience, neuroscientists Stéphanie Trouche and David Dupret from Oxford’s MRC Brain Network Dynamics Unit developed an experiment to test whether light from fiber optic cables pointed directly at brain cells could change them and whether the results could be controlled. The process is called optogenetics and was first tested in 2013 when researchers at MIT used it to implant false memories in a mouse’s brain by activating light-sensitive proteins with fiber optics. Trouche and Dupret took their experiment one step further and used optogenetics to change actual memories.
The neuroscientists first placed cocaine in a specific physical area so the mice would get addicted (now we know who to blame) and associate the positive memory of the drug with the place. The memory was formed in the hippocampus where different neurons are activated, depending on whether the experience was positive or negative, and later trigger a positive or negative emotion when the mouse returns to the location.
Once the scientists labeled the cells that became active in the coke room, they placed the mice in the area again. As the cells “turned on,” they hit them with the fiber optic light and turned them off. This automatically caused the opposite cells or “quiet neurons” to be activated, meaning that the memory of the place had been recoded. As they expected, the scientists found that the mice no longer associated the location with cocaine. Even more promising, the memory alteration was permanent.
The experiment proves that memories are stored as biological changes in the brain in response to external stimulation and that those memories can be manipulated and even reversed with optogenitics. If those memories are associated with an addiction, it’s possible that the addiction can be stopped with this technique.
Optogenitics is not yet ready for human testing. However, it’s definitely ready to be the plot for some new movies: Rodent Recall … 50 Furry Dates … Eternal Sunshine of the Cokeless Mouse.