Researchers Successfully Create, Erase And Restore Memories

On June 1st, 2014, a study published in the  journal “Nature”, was able to verify the means of memory creation, and show the possibility of their deactivation.

This was the first study of it’s kind in showing the ability to selectively remove a memory with one light, and predictably reactivate it using a different light.

Dr. Roberto Malinow, a neurosciences professor and senior author of this study, says that, “We can form a memory, erase that memory and we can reactivate it, at will, by applying a stimulus that selectively strengthens or weakens synaptic connections.”

This is developing work in what is referred to as optogenetics, which is a relatively new branch of neuroscience.  It is a method of using light to control neurons that have been genetically sensitized to light.  This of course, the cells of the rats’ brains were genetically engineered to respond to the light.

The scientists in this study applied optical stimulation to  a group of nerves in a rat’s brain that had been modified to make the neurons sensitive to light. While they were activating these neurons, they simultaneously delivered an electric shock to the rat’s foot.  The rats quickly learned to associate the optical nerve stimulation with pain, and they displayed fear behaviors when these nerves received stimulation.  The analysis of this process showed that chemical changes within the optically stimulated nerve synapses, which then showed synaptic strengthening.

The experiment’s next stage consisted of the research team demonstrating the ability to weaken the circuitry by using a low-frequency, memory-erasing train of optical impulses to stimulate those same nerves.  Subsequently these rats would no longer respond to the original nerve stimulation with fear, suggesting that the memory of pain-association had been erased.