WIKIMEDIA, GENNY ANDERSONResearchers have transferred a memory from one snail to another via RNA, they report today (May 14) in eNeuro. The UCLA team suggests their research might one day allow us to, as the study states, "modify, enhance, or depress memories".
Researchers have successfully transferred a sea snail's memory to another one by injecting RNA from a trained sea snail into an untrained one.
For decades, researchers have tried to pinpoint how, when, and where memories form. Even more impressive? That early research may someday pave the way for similar processes in humans.
Study coauthor David Glanzman of the University of California, Los Angeles, has been working on the cell biology of learning and memory for almost 40 years, and says for the majority of that time he believed memory was stored at synapses.
The marine snails or Aplysia Californica were given minor electric shocks by the scientists only after proper administration of the shocks.
The work of Glanzman and his team, however, lends weight to an emerging counter-theory that suggests long-term memory is actually stored within the cell bodies of the neurons themselves.
"It was completely arbitrary which synaptic connections got erased", Glanzman says.
"Engram" is the word used to denote the physical substrate of memory - the structure inside the brain that physically stores long term memories, broadly analogous to the way a hard-drive stores data on a computer.
"If memories were stored at synapses, there is no way our experiment would have worked", he said, the BBC reported. Like all mollusks, these snails have groups of neurons called ganglia, rather than brains. When the researchers subsequently tapped the snails, they found those that had been given the shocks displayed a defensive contraction that lasted an average of 50 seconds, a simple type of learning known as "sensitization".
Once the reflex action had been established in the trained snails, they were euthanised and their abdominal ganglia removed.
This idea is probably going to strike most of my colleagues as extremely improbable.
The snails in one group were trained to respond to a stimulus - a mild election shock on the tail - which triggered a defensive withdraw reflex.
The second group then received the shocks and the snails contracted for only about two seconds.
DNA methylation appeared to be essential for the transfer of the memory among snails.
Once this initial phase of the experiment was completed, the researchers extracted RNA from the sensitized sea hare snails and injected it into untrained specimens.
First, they had to train sea snails. The trained RNA also increased the excitability of cultured sensory neurons, obtained from untrained animals, which control this reflex.
The idea "seems quite radical as we don't have a specific mechanism for how it works in a non-synaptic manner", Bong-Kiun Kaang, a neuroscientist at Seoul National University who was not involved in the study, writes in an email to The Scientist.