My worst nightmare is something like Wolverine's origin story... my memories of everything I've done up until this point are completely erased by evil scientists. I don't remember my wife, my pets or even that horrible thing I did in high school to my neighbor's mailbox. The unfortunate reality is that we're all losing our memory, just not in big chunks of induced amnesia. However, researchers at the University of California, San Diego School of Medicine have taken us a step closer to being able to control our memories. They recently erased the memories of rats. Then, they reactivated those memories, reminding the rats of what they should have already known about their past.
This study was published in the June issue of "Nature" and showed that memories can be removed and also replaced by stimulating nerves in the brain at frequencies that weaken or strengthen the connections between synapses. After the team shocked the rats' feet and genetically modified them to be sensitive to light, the animals learned to associate optical stimulation with pain. In simple terms, they made the rats afraid of light.
Following this torment, the scientists then stimulated the rats' optical nerves with a low-frequency. Afterward, the rats were no longer afraid of light. Their memories of being electrically shocked were erased and they forgot the pain. This in itself is extraordinary, but then the scientist re-activated the rats' memories by stimulating those same nerves with high-frequency pulses. Once again, the rats were scared of light.
You may be wondering why someone would electrocute rats and erase their memories all day. The answer is a clinical application for Alzheimer's disease, which weakens synaptic connections in humans the same way the low-frequencies erased the rats' memories. Potentially, this research could counteract the effects of Alzheimer's. This is the most prevalent form of dementia, affecting some 4.5 million people in the United States alone. As of now, it has no cure and always results in the death of the victim, destroying the neurons in their brain. The high-frequency pulses used on the rats in this experiment may hopefully combat beta-amyloid plaques that clump along Alzheimer's victims' neurons, entangling them.
While we don't fully understand how our memory system works, the authors of this study believe they can form a memory, erase that memory and reactivate it. If a memory begins with encoding, it is stored with both electricity and chemicals, connecting across the brain through synapses. The more signals sent between synapses, the stronger the connection grows. Sometimes when we forget something it's because it wasn't encoded properly in the first place. But with a disease like Alzheimer's, the synapses themselves are affected.
The ability to restore the memories of our suffering friends and families would be a great achievement. I just hope that I never find myself on the darker side of this science, strapped to a gurney with low-frequency pulses erasing everything I've ever known or done.