In 2008, researchers from UCLA and the Weizmann Institute of Science in Israel determined that certain memories could be traced to specific neurons. Dr. Itzhak Fried said, “Reliving past experience in our memory is the resurrection of neuronal activity from the past.”
Some scientists believe that our memories can be changed. We might have very clear memories of an event, but psychologists say those memories aren’t very accurate. Karim Nader believes that memories are altered just by the act of remembering. See How Our Brains Make Memories in Smithsonian Magazine.
Flash forward to 2014 when researchers at University of California, San Diego School of Medicine erased and reactivated memories in rats. The study, published June 1, 2014 in Nature online, began by teaching the rats to associate optical nerve stimulation with pain. The rats were afraid when the same nerves were later stimulated. When the nerves were restimulated with a low frequency train of optical pulses, pain memories were erased.
Scientists were surprised to find that restimulating the nerves with a high frequency train of optical pulses could then reactivate the lost memory.
“We can cause an animal to have fear and then not have fear and then to have fear again by stimulating the nerves at frequencies that strengthen or weaken the synapses,” said Sadegh Nabavi, a postdoctoral researcher in the Malinow lab and the study’s lead author.
In terms of potential clinical applications, Roberto Malinow, MD, PhD, noted that the beta amyloid peptide that accumulates in the brains of people with Alzheimer’s disease weakens synaptic connections in much the same way that low-frequency stimulation erased memories in the rats. “Since our work shows we can reverse the processes that weaken synapses, we could potentially counteract some of the beta amyloid’s effects in Alzheimer’s patients,” he said.
That’s great news, but I read a lot and probably am overly imaginative. I can see where messing with the brain — particularly erasing or creating memories — opens up a whole new can of ethical and moral dilemmas. It also makes me wonder about false memories in general and whether victims of PTSD could be helped.
I know too many people who believe that their memories are 100 percent accurate and are never wrong. It should be fascinating when the research is applied to human beings.