Meanwhile, the untrained snails who had received RNA from untrained donors did not exhibit any change in their defensive response. This research could lead to new ways to lessen the trauma of painful memories with RNA and to restore lost memories.
A form of genetic information called RNA ribonucleic acid, which influences the way genes are expressed, was inserted into snails during the experiment.
As it turned out, the RNA samples retained the memory of the electric shock, causing the untrained snails to exhibit a defense mechanism that lasted nearly as long as that of the donor snails. These shocks were said to enhance the withdrawal reflex of the snail, a defensive contraction it displays to protect itself from a potential threat.
When the researchers subsequently tapped the snails, they found those that had been given the shocks displayed a defensive contraction lasting about 50 seconds, while those that had not received the shocks contracted for only about one second.
For the next step, RNA was extracted from both the trained and untrained snails. Here, it is reported that RNA extracted from the central nervous system of Aplysia given long-term sensitization training induced sensitization when injected into untrained animals; furthermore, the RNA-induced sensitization, like training-induced sensitization, required DNA methylation.
Palestinians dead, as protests of US Embassy opening in Jerusalem turn deadly
Vice President Mike Pence spoke Monday at an event in Washington, D.C., to mark the opening of the USA embassy in Jerusalem . More than 2 million people are crammed into the narrow Gaza strip, which is blockaded by Egypt and Israel.
In comparison, snails tapped without electricity retreated for an average of 10 seconds.
They saw a similar effect when they did the same thing to sensory nerve cells being studied in petri dishes.
"It's as though we transferred the memory", Glanzman said. "So these snails are alarmed and release ink, but they aren't physically damaged by the shocks", he said.
This challenges the traditional neurosciences findings that state memory is stored as a result of connections that are formed between brain cells (neurons). Kaang notes there are "many critical questions that need to be addressed to further validate the author's argument", such as what kinds of noncoding RNAs are specifically involved, how are the RNAs transferred among neurons, and how much do RNAs at the synapse play a role?
"If memories were stored at synapses, there is no way our experiment would have worked", he said, leading him to believe memories are actually stored in the nucleus of neurons.
Memories persist in synapses - junctions in the brain's neural circuitry. The paper might support hints from studies conducted decades ago that RNA was involved in memory. It is now understood to have other important functions besides protein coding, including regulation of a variety of cellular processes involved in development and disease.