A simple injection transferred memories from one group of snails to another, a startling finding that runs counter to our current understanding of how memories are stored.
Neuroscientists trained snails to recoil from mild electrical shocks for an extended period of time—up to a minute—then extracted a messenger molecule known as RNA and injected it into snails that hadn’t been zapped. The injected snails reacted to gentle touches in the same way that the zapped snails had, while those injected with RNA from untrained snails withdrew for only a short time.
David Glanzman, a professor at UCLA, and his colleagues also performed similar experiments on shocked and control snail neurons in Petri dishes, measuring how excitable they were. The results of the two experiments, he said, suggests that memories may be stored in the nucleus of neuron cells. Currently, most neuroscientists believe that memories are stored in connections between neurons, known as synapses, not simply within the cells themselves.
Here’s Usha Lee McFarling, reporting for Stat:
“This idea is radical and definitely challenges the field,” said Li-Huei Tsai, a neuroscientist who directs the Picower Institute for Learning and Memory at the Massachusetts Institute of Technology. Tsai, who recently co-authored a major review on memory formation, called Glanzman’s study “impressive and interesting” and said a number of studies support the notion that epigenetic mechanisms play some role in memory formation, which is likely a complex and multifaceted process. But she said she strongly disagreed with Glanzman’s notion that synaptic connections do not play a key role in memory storage.
The idea that RNA may be responsible for memory storage dates back to the 1950s. In the years that followed, many scientists were unable to recreate the initial experiments that gave rise to the idea. But recently, some have succeeded, reopening the debate. Glanzman and his colleagues’ work arrives at what might be a pivotal moment in our understanding of memory.