Memory Transferred Between Sea Snails

Monday, May 14, 2018

Memory Transferred Between Sea Snails

⯀ Memory transfer has been at the heart of science fiction for decades, but it may be one step closer to fact, pending research done on aquatic snails. A team claims to have successfully transplanted memories by transferring a form of genetic information called RNA from one snail into another.

Neuroscientists at UCLA have reported that they have transferred a memory from one animal to another via injections of RNA, a startling result that challenges the widely held view of where and how memories are stored in the brain.

The finding from the lab of David Glanzman hints at the potential for new RNA-based treatments to one day restore lost memories and, if correct, could shake up the field of memory and learning.

“It’s pretty shocking,” said Dr. Todd Sacktor, a neurologist and memory researcher at SUNY Downstate Medical Center in Brooklyn, N.Y. “The big picture is we’re working out the basic alphabet of how memories are stored for the first time.” He was not involved in the research, which was published in eNeuro, the online journal of the Society for Neuroscience.

It is generally accepted that long-term memory (LTM) is encoded as alterations in synaptic strength. An alternative model, however, proposes that LTM is encoded by epigenetic changes.

The work was performed using snails, animals that have proven a powerful model organism for neuroscience but whose simple brains work far differently than those of humans. 

The experiment involved giving mild electrical shocks to the marine snail Aplysia californica. Shocked snails learn to withdraw their delicate siphons and gills for nearly a minute as a defense when they subsequently receive a weak touch; snails that have not been shocked withdraw only briefly.
snail memory transplant

The researchers extracted RNA from the nervous systems of snails that had been shocked and injected the material into unshocked snails.

RNA’s primary role is to serve as a messenger inside cells, carrying protein-making instructions from its cousin DNA. But when this RNA was injected, these naive snails withdrew their siphons for extended periods of time after a soft touch. Control snails that received injections of RNA from snails that had not received shocks did not withdraw their siphons for as long.

The results, said Glanzman, suggest that memories may be stored within the nucleus of neurons, where RNA is synthesized and can act on DNA to turn genes on and off. He said he thought memory storage involved these epigenetic changes—changes in the activity of genes and not in the DNA sequences that make up those genes—that are mediated by RNA.

“It’s as if we transferred a memory,” Glanzman said.

"The big picture is we’re working out the basic alphabet of how memories are stored for the first time."

These findings raise the possibility that RNA could be used to modify memory. The experiments will need to be replicated, including in animals with more complex brains for verification. As the results fly in the face of a massive amount of evidence supporting the deeply entrenched idea that memories are stored through changes in the strength of connections, or synapses, between neurons, there is a lot of follow up work needed in this case.


By  33rd Square