homehome Home chatchat Notifications


Scientists transfer memories between snails with RNA implants

Memory may be far more complex than meets the eye.

Tibi Puiu
June 20, 2019 @ 7:13 pm

share Share

 

The California sea hare, Aplysia californica. Credit: Wikimedia Commons.

The California sea hare, Aplysia californica. Credit: Wikimedia Commons.

An exciting new research study suggests the possibility that some memories can be transferred between organisms. Scientists extracted ribonucleic acid (RNA) from a trained sea snail and implanted it into an untrained snail, whose behavior then matched that of the donor animal.

Where is my mind?

When the brain deems an experience meaningful enough, it will transfer that information from short-term storage — the temporary file cabinet which holds information like where you put your car keys or the phone number of a person you just met — to your long-term memory, where information is stored so that it can be accessed at a later time. Scientists think that this record is made in the brain by strengthening the connections between groups of neurons that participate in encoding the experience a pattern of connections which is referred to as an engram.

In 2012, MIT researchers identified the particular brain cells in the hippocampus that were active only when a mouse was learning about a new environment. They then proceeded to identify which genes were activated in those cells and added the gene for channelrhodopsin-2 (ChR2), a light-activated protein used in optogenetics, into a genetically engineered mouse. Using tiny optical fibers embedded in the animals’ skulls, the researchers could deliver pulses of light to hippocampal dentate gyrus neurons, thereby manipulating their activity. 

The mice were introduced to a new environment and were then left to acclimate themselves with a few minutes of exploration. A mild foot shock was then suddenly introduced, causing the mice to fear that environment. The activated brain cells were tagged with ChR2. Later, the mice were introduced in a totally different environment, with an obviously different maze and smell, and were again left there to explore. A pulse of light was fired onto the neurons involved in the first experience, causing the fear memory to switch on and the mice to quickly enter a defensive, immobile crouch. The rodents had, essentially, been fear conditioned.

“Our results show that memories really do reside in very specific brain cells,” co-author Xu Liu stated at the time, “and simply by reactivating these cells by physical means, such as light, an entire memory can be recalled.”

This landmark research study showed that long-term memories are stored in modified connections between brain cells, which can be recalled on command. However, recent evidence also points to an alternative explanation: memories might be stored in changes in gene expression induced by non-coding RNA (ncRNA) — an RNA molecule that is not translated into a protein.

Credit: Bédécarrats et al., eNeuro (2018).

Credit: Bédécarrats et al., eNeuro (2018).

David Glanzman and colleagues at the University of California, Los Angeles, trained a California sea hare (Aplysia californica) to form a conditioned response by stimulating their tail, triggering an involuntary defensive reflex. The team then proceeded to extract RNA from these trained snails and injected it into untrained animals. The latter group inherited a similar sensitized response.

Researchers also showed that RNA extracted from trained snails increased the excitability of cultured sensory neurons, which were obtained from untrained animals and which controlled the involuntary reflex.

The findings provide evidence that RNA may be involved in memory modification, which suggests that memory storage is far more complex than meets the eye.

Reference: RNA from Trained Aplysia Can Induce an Epigenetic Engram for Long-Term Sensitization in Untrained Aplysia, eNeuro.

share Share

Doctor Discovers 48th Known Blood Group and Only One Person on Earth Has It

A genetic mystery leads to the discovery of a new blood group: “Gwada negative.”

More Than Half of Intersection Crashes Involve Left Turns. Is It Time To Finally Ban Them?

Even though research supports the change, most cities have been slow to ban left turns at even the most congested intersections.

A London Dentist Just Cracked a Geometric Code in Leonardo’s Vitruvian Man

A hidden triangle in the vitruvian man could finally explain one of da Vinci's greatest works.

The Story Behind This Female Pharaoh's Broken Statues Is Way Weirder Than We Thought

New study reveals the ancient Egyptian's odd way of retiring a pharaoh.

China Resurrected an Abandoned Soviet 'Sea Monster' That's Part Airplane, Part Hovercraft

The Soviet Union's wildest aircraft just got a second life in China.

A Rocket Carried Cannabis Seeds and 166 Human Remains into Space But Their Capsule Never Made It Back

The spacecraft crashed into the Pacific Ocean after a parachute failure, ending a bold experiment in space biology and memorial spaceflight.

Ancient ‘Zombie’ Fungus Trapped in Amber Shows Mind Control Began in the Age of the Dinosaurs

The zombie fungus from the age of the dinosaurs.

Your browser lets websites track you even without cookies

Most users don't even know this type of surveillance exists.

Ozempic Users Are Seeing a Surprising Drop in Alcohol and Drug Cravings

Diabetes drugs show surprising promise in reducing alcohol and opioid use

What's Seasonal Body Image Dissatisfaction and How Not to Fall into Its Trap

This season doesn’t have to be about comparison or self-criticism.