United States scientists transfer memory from one snail to another by transplanting RNA

The California sea hare Aplysia californica. Credit Wikimedia Commons

The California sea hare Aplysia californica. Credit Wikimedia Commons

The experiment was conducted on the poisonous snails Aplysia.

UCLA biologists report they have transferred a memory from one marine snail to another, creating an artificial memory, by injecting RNA from one to another.

Senior study author David Glanzman, from UCLA's Department of Integrative Biology and Physiology, pointed out that the snails used in the experiment were not hurt in any way.

For this objective, the injection of specific ribonucleic acids. The research provides new clues in the search for the physical basis of memory. That makes the animals more sensitive, so that in response to stimuli they defensively withdraw for longer than they normally would. By repeatedly shocking the snail's tail, the animal learns to stay in that defensive position when touched on the siphon, even weeks after the shocks end.

The snails' reflex to retreat into their shells was more pronounced - the defensive withdrawal reflex lasting up to 50 seconds. Those that had not been given the shocks contracted for only about one second.

Glanzman wanted to know if the RNA from shocked snails actually affected the neuronal connections of the snails receiving the injections any differently than RNA from nonshocked snails.

After sensitising the sea snails, Glanzman extracted RNA from the animals and injected it into other sea snails to see what happened.

Scientists extracted RNA from the nervous systems of the snails that received the shocks and injected it into a small number of marine snails that had not been sensitised in this way.

But in a new study, researchers claim to have made headway in understanding the simplest kind of memory a mollusc might form, and, with a swift injection, managed to transfer such a memory from one sea snail to another.

As expected, the control group of snails did not display the lengthy contraction.

Researchers in the U.S. achieved the feat by first teaching a group of Aplysia snails - using a series of mild electric shocks - to associate potential danger with a harmless tap on the outside of their shells. And sea snails are no exception - their nerves transmit impulses much the way ours do. And of course, the unshocked snail RNA had no effect on neurons at all. (Each neuron has several thousand synapses.) Glanzman holds a different view, believing that memories are stored in the nucleus of neurons.

Glanzman said the snail memory transplant shows memories may not reside in synapses as previously thought. The cell and sub-atomic procedures appear to be fundamentally the same as between the marine snail and people, despite the fact that the snail has around 20,000 neurons in its focal sensory system and people are pondered 100 billion. He and his colleagues published research in the journal eLife in 2014 indicating that lost memories can be restored. Note: material may have been edited for length and content.

Co-creators are Alexis Bédécarrats, a UCLA postdoctoral researcher who worked in Glanzman's lab; and Shanping Chen, Kaycey Pearce and Diancai Cai, examine relates in Glanzman's lab.

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