Memory RNA

Memory RNA is a now-discredited hypothetical form of RNA that was proposed by James V. McConnell and others as a means of explaining how long-term memories were stored in the brain. The concept behind it was that since RNA encoded information, and since living cells could produce and modify RNA in reaction to external events, it might also be used in neurons to record stimuli.

One experiment that was purported to show a chemical basis for memory involved training planaria (flatworms) to solve an extremely simple "maze", then grinding them up and feeding them to untrained planaria to see if they would be able to learn more quickly. The experiment seemed to show such an effect, but it was later determined that the original planaria had left chemical tracks inside the maze itself that were not properly cleaned away before the next set of planaria were run.