Did I post this before? I have no way of knowing. New Scientist tells me (for what I hope is the first time) that researchers have found a single enzyme that can erase specific memories:
Several years ago, researchers showed that injecting mice with a drug that stops new proteins from forming can block an old memory as it is recalled.
And last year, another team found that inhibiting a specific protein can erase old memories, even without recalling them.
Based on previous experiments that showed that α-CaMKII was important to a cellular phenomenon thought to underlie memory formation, [Medical College of Georgia neuroscientist Joe] Tsien’s team bred mice engineered to make extra levels of the enzyme. His team could return their α-CaMKII levels to normal by giving the mice a drug that blocked only the engineered copy.
To test the effect of the change, Tsien and colleagues at the East China Normal University in Shanghai gave mice a slight shock in a training chamber while playing a loud tone.
With thoughts of a jolt fresh in their brain, mice with normal levels of α-CaMKII froze up when they returned to the chamber an hour later, while mice with boosted levels remained calm.
Even a month after the shock – enough time for mice to store the memory for good – cranking up α-CaMKII eroded all memories of the shock treatment, Tsien’s team found.
Tsien believes α-CaMKII (also called calcium/calmodulin kinase II) acts something like a detergent, weakening or dissolving the connections between brain cells that are built when a memory forms.
You can read more about the discovery at eFlux Media.