|In a scientific first researchers have transferred memories between sea
snails by injecting RNA from a trained sea snail into one that hasn't
been trained - and observing the trained response in the second snail.
The researchers from the University of California, Los Angeles, were
hoping to understand something called the engram - a physical trace of
memory storage. Recent studies have found that long-term memory can be
restored after amnesia with the aid of a priming component. This process
seems to involve epigenetic modification - something RNA is heavily
involved in. And RNA is also involved in the process of forming
long-term memories. This led the team to the possibility that some
aspects of long-term memory could be transferred via the molecule.
To test their hypothesis, they trained sea snails by applying a mild,
but still unpleasant, electric shock to the tails of a sea snail called
Aplysia californica. The researchers administered five electric shocks
to the training group of snails, one every 20 minutes. Then, 24 hours
later, the researchers repeated the process. When researchers tapped the
snails afterward, those that had received the shock training contracted
their bodies into a defensive posture for an average of around 50
seconds - but the snails that had not been trained only contracted for
about one second.
For the next step, RNA was extracted from both the trained and untrained
snails. The molecules were then injected into two groups of untrained
snails. The untrained snails that had received RNA from the trained
group then responded to taps as though they had been shocked too -
contracting defensively for an average of 40 seconds. Meanwhile, the
untrained snails who had received RNA from untrained donors did not
exhibit any change in their defensive response.