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Snail Memory Transplant Performed Using RNA, Scientists Say

Snail Memory Transplant Performed Using RNA, Scientists Say

Scientists at the University of California in Los Angeles carried out the transplant of memory from one sea snail to the other through the injection of specific ribonucleic acids (RNA). In other words, the memory of an electric shock suffered in another organism. In 2016, for example, the Austrian scientist Patrick C. Trettenbrein pointed out a number of problems with the synapse-memory theory-but noted that "we are now also still lacking a coherent alternative".

The idea that RNA may be responsible for memory storage dates back to the 1950s.

More studies will have to show if this experiment can work in humans.

"It's as though we transferred the memory", said David Glanzman, who is also a member of UCLA's Brain Research Institute.

This groundbreaking experiment began with training a group of sea snails belonging to the Aplysia californica species, colloquially known as the California sea hare. He found the recipient sea snails became sensitised, suggesting the "memory" of the electrical shocks had been transplanted.

"It was completely arbitrary which synaptic connections got erased", Glanzman says. Short term memories are stored in the pre-fontal lobe.

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Traditionally, long-term memories were thought to be stored at the brain's synapses, the junctions between nerve cells. He picked Aplysia because it has been a longtime model organism for memory studies. Sticking electrodes in the snail's tail and shocking it makes this defensive response last longer, tens of seconds, and sometimes up to nearly a minute. The process was repeated with some of the untrained animals.

This idea is probably going to strike most of my colleagues as extremely improbable.

The next step was to extract RNA from the snails' nervous systems, but only from those that had received the shocks. When the snails were tapped slowly by the researchers, the snails that received a shock displayed a slight contraction that lasted for 50 seconds but the ones without any shock treatment showed contractions only for one second.

Researchers also extracted RNA from snails that had not received any shocks, and transferred it to another group of snails that also had not been shocked. This produced "increased excitability" in the neurons, according to the UCLA statement, whereas RNA from un-shocked snails did not. But scientists have gradually realized that there is more to RNA than playing messenger. Kaang notes there are "many critical questions that need to be addressed to further validate the author's argument", such as what kinds of noncoding RNAs are specifically involved, how are the RNAs transferred among neurons, and how much do RNAs at the synapse play a role?

He also stressed that the snails did not get hurt: "These are marine snails and when they are alarmed they release a attractive purple ink to hide themselves from predators".

As Glanzman points out, if that theory were true, then the experiment wouldn't have succeeded.