Scientists have successfully transferred a memory from one marine snail to another — but there's still a long way to go until you can pay someone to wipe unpleasant memories or implant new ones a la Total Recall, or Eternal Sunshine of the Spotless Mind.

Key points: The study helps improve scientists' understanding of memory

The study helps improve scientists' understanding of memory Cellular and molecular processes of humans and snails are very similar

Cellular and molecular processes of humans and snails are very similar It may pave the way for better treatments for post-traumatic stress disorder and Alzheimer's in the future

Researchers in the US 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.

Then, when scientists gave those marine molluscs a light knock, they withdrew into their shells in defence for 50 seconds.

A second, untrained, group of snails only retreated for 1 second upon receiving a tap.

That is, until researchers injected ribonucleic acid (RNA) from the trained snails into the second group.

Professor Glanzman holds a sea snail. ( Supplied: UCLA/Christelle Snow )

All seven of the snails that received the new RNA then went on to hide in their shells for an average of 40 seconds when the scientists came knocking, according to a paper published today in the journal eNeuro.

"It's as though we transferred the memory," said the study's senior author, David Glanzman, from the University of California, Los Angeles.

The scientists also injected RNA from one group of untrained snails into another to make sure it wasn't just the injection process that caused the snails to change their behaviour.

An even closer look showed the new RNA even changed the way the snails' sensory (but not motor) neurons behaved in a petri dish.

What that means for science — and human wellbeing

The findings of the study could affect our understanding of memory.

Scientists have long believed memories were stored in the arrangement of synapses, the connections between neurons.

But Professor Glanzman thinks the cells themselves play a much more important role.

"If memories were stored at synapses, there is no way our experiment would have worked," he said.

He said cellular and molecular processes of humans and snails were very similar.

Professor Glanzman said in future it might be possible to awaken and restore memories that have gone dormant in the early stages of Alzheimer's disease, or ameliorate the effects of post-traumatic stress disorder.