Written by Annie Duong and Edited by Amy Huynh
Creating and implanting memories may sound like the plot of a dystopian science fiction novel. However, at the University of California, Los Angeles, Professor David Glanzman and his research team have made this a reality by demonstrating a way to “transfer” memories from one individual snail to another [1].
Long-term memories are memories that have stored information for an extended period of time and are thought to be solidified through strengthened connections between brain cells. Professor Glanzman’s research indicates another possibility: these long-term memories may have been stored within the cells themselves through a type of messenger known as RNA, or ribonucleic acid, which is a copy of DNA containing critical information needed for regular cell function and activity.
A group of marine snails of species known as Aplysia were put through behavioral training with electric shocks administered through a wire to elicit a withdrawal reflex, which is a natural response to avoid harm. They were given a total of five shocks, which were delivered every 20 minutes. After this procedure, the snails were allowed 24 hours to recover and the same procedure of shocks was administered again. Then, the amount of time the snails’ tail ends were contracted was measured by tapping the tail ends with a probe. These contraction periods were approximately 50 seconds long, demonstrating that the snails had undergone a type of simple learning called sensitization. The repeated stimuli resulted in a progressive magnificated response; in this case, a longer contraction period [2].
Next, RNA was extracted from the snails that were sensitized and from the snails that were not sensitized. The RNA from the sensitized group was injected into the latter group and the RNA from the control group was injected into an additional control group [2]. The results found were quite remarkable: the group of snails that received the sensitized snails’ RNA demonstrated a similar extended contraction period of 40 seconds while the control group of snails that received RNA from snails that did not undergo any type of training demonstrated the typical contraction of 1 second [2]. The snails had somehow gained the memory of contracting their tails for a longer period than normal in response to a stimulus on their tails.
These results demonstrate that memory can be encoded into our own genetic information. It also can contribute to potential treatment for patients suffering from Alzheimer’s disease by enhancing memories that become dormant in Alzheimer’s early stages. Similarly, it may treat those with post traumatic stress disorder (PTSD) by depressing their memories. Although this does not necessarily refute that strengthening synaptic connections between brain cells contributes to memory formation, these are promising results that could further our understanding about how the brain stores memories.
References:
- “Biologists ‘Transfer’ a Memory through RNA Injection.” ScienceDaily, ScienceDaily, 14 May 2018, www.sciencedaily.com/releases/2018/05/180514151920.htm.
- Bedecarrats, A., Shanping C., Kaycey, P., Cai, D. and Glanzman, D. 2018. RNA from Trained Aplysia Can Induce an Epigenetic Engram for Long-Term Sensitization in Untrained Aplysia. eNeuro. 1 – 33.