Therapeutic Memory Implants

Image Source: Yahoo.

From Yahoo News:

[A] team of researchers successfully implanted false memories in mice.

To implant the memories, the researchers something called used optogenetics — the use of optics and genetics to control individual neurons in the brain. They first genetically engineering mice so that they would have light-sensitive proteins — called Channelrhodopsin-2 or ChR2 — in their hippocampus, which is the part of the brain used in forming memories. Therefore, when the mouse formed memories, the researchers could effectively see which regions of the hippocampus were activated. Also, using light they could activate those areas to have the mouse recall those memories, and they achieved that by having a thin fibre optic cable implanted in the mouse's head.

Placing the mouse into a box — called Chamber A — they let it calmly explore for 10 minutes, forming memories about its environment, and they recorded where the memories were formed ... .

The next day, they placed the mouse into a different box — Chamber B — with a different environment, and they used light through the fibre optic cable to activate the memories it formed the day before. At that time, while the mouse was remembering Chamber A, they delivered mild shocks through the floor of the box, which caused the mouse to freeze in place ... .

"Here, we were trying to artificially make an association between the light-reactivated memory and the foot shocks. We were just trying to artificially connect the two," said Steve Ramirez, a graduate student at the RIKEN-MIT Center for Neural Circuit Genetics in Cambridge, Massachusetts, who participated in the research, according to Discovery News.

Then, putting the mouse back into Chamber A, the mouse froze in fear, apparently remembering that its feet had been shocked in this chamber, even though the shocks took place in the completely different environment of Chamber B (panel 3 of the image above).

"They appeared to be recalling being shocked in box A, even though that had never happened," Ramirez said, according to Discovery News. "A false memory had been formed and recalled."

Given the fictional applications we've seen for this kind of work, it's easy to see the dark side of this research and its potential use in a dystopian future, but this could have some remarkable therapeutic uses in the present day. Imagine a trauma victim recalling the memories of their trauma, and then having happier memories stimulated to alleviate their stress.

Discovery News expanded on this story with reference to therapeutic applications for veterans with PTSD:

For example, a combat veteran suffering from PTSD could be asked to remember a stressful time, while a physician stimulated a part of the hippocampus known to produce more pleasant memories.

Ramirez noted that the technique used on humans would probably not involve a fiber optic cable, since that's invasive. But it could involve some kind of drug-induced stimulation, since there are already a number of drugs that target specific brain regions -- recreational drugs, for instance, target reward centers. The trick would be making one that focused on a protein or receptor unique to the hippocampus.

The experiment also sheds light on how humans form false memories, said Tonegawa. There are some dramatic examples of people suddenly having a memory of a traumatic event, such as childhood sexual abuse. But sometimes whether the memory is true or not becomes controversial. Tonegawa said his team's most recent work provides an animal model of how false memories can appear. Further work needs to be done to show if false memories look different from the real thing.

Readers of more dystopian science fiction might ask if this could be used for mind control. Ramirez said he is conscious of that, even though such an experiment with current technology would never pass muster with an ethics review board. "It's important to be having these conversations now," he said.