“We induced a very simple kind of memory in the snails called sensitization,” said David L. Glanzman, a member of UCLA’s department of Integrative Biology and Physiology and the lead author of the study.
He likens sensitization to experiencing an earthquake or other physically jarring event. “You’d be very jumpy for a time afterward,” he said.
Glanzman and his team gave the snails a series of electric shocks to their tails. “The result is, their reflexes were greatly enhanced. If we touched their skin, they’ll contract very strongly.”
When the snails were good and jumpy, the team extracted RNA from their nervous systems and injected it into untrained snails.
“Twenty-four hours later, we tested the reflexes of those snails, and they showed the same reflexes of those that had been given electrical shocks,” Glanzman said.
It’s no coincidence that this breakthrough was conducted with the help of some slimy gastropod friends. Glanzman says neurobiologists have been studying the machinations of snail brains for decades.
“I’m a reductionist in my approach to learning memory,” he said. “Human brains are so complex … so snails have a lot of advantages in that they have relatively simple nervous systems.”
And what applies to a snail, evolutionarily, probably applies to a human in some way.
“The way science proceeds is, you figure out the simple things first, and then you build on them,” Glanzman said. “Many of the cellular mechanisms of learning and memory that we identify in all animals were first observed in the snail.”
What does it mean for humans?
Memory transfer and transplantation are fascinating to think about. But just because it works on snails doesn’t mean we’ll soon be living in the realm of “Westworld” or “The Eternal Sunshine of the Spotless Mind.” Actually, the human applications are much more practical — and helpful.
“We were able to transfer the memory using RNA,” Glanzman said. “So if you think about human disorders of memory like dementia, Alzheimer’s and PTSD, if we can identify some of the RNA that produces learning like alterations, it is possible we could use that knowledge to create new and more effective treatments.”
In other words, a better understanding of how memories are physically formed in the components of the nervous system (which includes the brain) could lead to a better understanding of memory-related diseases and disorders.”
The findings also challenges some popular understandings of how memory is stored.
“The dominant model of learning and neuroscience today is that when an animal learns something, there is growth in new synaptic connections or change in existing ones,” Glanzman said. “So essentially, memory is stored in synapses. Our study suggests that can’t be true.”