Chocolate makes snails smarter

Sep 27, 2012
snail

Chocolate isn't usually on the diet for snails, but when Lee Fruson and Ken Lukowiak from the University of Calgary, became curious about the effects of diet on memory, they decided to try a flavonoid from chocolate, epicatechin (epi) on the pond snail Lymnaea stagnalis to see if it improved the animals' memories. After a dose of epi, the pond snails were able to remember a training protocol for longer and the memories were stronger.

Type the word ',' into a web browser and you'll be overwhelmed: some websites even maintain that can have beneficial effects. But take a closer look at the science underpinning these claims, and you'll discover just how sparse it is. So, when University of Calgary undergraduate Lee Fruson became curious about how dietary factors might affect memory, Ken Lukowiak was sceptical. "I didn't think any of this stuff would work," Lukowiak recalls. Despite his misgivings, Lukowiak and Fruson decided to concentrate on a group of compounds – the – found in a wide range of 'superfoods' including chocolate and green tea, focusing on one particular flavonoid, epicatechin (epi). However, figuring out how a single component of chocolate might improve is almost impossible – too many external factors influence – so Lukowiak turned to his favourite animal, the pond snail Lymnaea stagnalis, to find out whether the dark chocolate flavonoid could improve their memories. They publish their discovery that epi improves the length and strength of snail memories in The .

According to Lukowiak, the molluscs can be trained to remember a simple activity: to keep their breathing tubes (pneumostomes) closed when immersed in deoxygenated water. He explains that usually breathe through their skins, but when fall, they extend the breathing tube above the surface to supplement the . However, the snails can be trained to remember to keep the closed in deoxygenated water by gently tapping it when they try to open it, and the strength of the memory depends on the training regime.

First, Fruson identified an epi concentration – 15 mg m3 pond water – that didn't affect the snails' behaviour; 'We have to be sure that we're not looking at wired animals', chuckles Lukowiak. Then, the duo tested the molluscs' memories. Explaining that a half-hour training session in deoxygenated water allows the snails to form intermediate-term memories (lasting less than 3 h) but not long-term memories (lasting 24 h or more), Fruson and Lukowiak wondered whether epi would improve the snail's memories, allowing them to form long-term memories after shorter memory training. Amazingly, when Fruson plunged the molluscs into deoxygenated water to tested their memories a day later, they remembered to keep their breathing tubes closed. And when the duo provided the snails with two training sessions, the animals were able to remember to keep their breathing tubes shut more than 3 days later. Epi had boosted the ' memories and extended the duration, but how strong were the epi-memories?

Lukowiak explains that memories can be overwritten by another memory in a process called extinction. However, the original memory is not forgotten and if the additional memory is stored weakly, it can be lost and the original memory restored. So, Fruson and Lukowiak decided to find out how strong the epi-boosted memory was by trying to extinguish it. Having trained the snails, the duo then tried to replace it with a memory where the snails could open their breathing tubes. However, instead of learning the new memory, the epi-trained snails stubbornly kept their breathing tubes shut. The epi-memory was too strong to be extinguished.

The duo also found that instead of requiring a sensory organ to consolidate the snails' memories – like their memories of predators triggered by smell – epi directly affects the neurons that store the memory. So, Lukowiak is keen to look directly at the effect that epi has on memory neurons and adds that the cognitive effects of half a bar of dark chocolate could even help your grades: good news for chocoholics the world over.

Explore further: 'Femme fatale' emerald ash borer decoy lures and kills males

More information: Fruson, L., Dalesman, S. and Lukowiak, K. (2012) A flavonol present in cocoa [(–)epicatechin] enhances snail memory. J. Exp. Biol. 215, 3566-3576. jeb.biologists.org/content/215/20/3566.abstract

Related Stories

Snails on methamphetamine

May 28, 2010

Crystal meth (methamphetamine) is a highly addictive drug that seduces victims by increasing self-esteem and sexual pleasure, and inducing euphoria. But once hooked, addicts find the habit hard to break. Barbara ...

Can you make a snail forget?

Jun 29, 2010

Predator scent enhanced the ability of pond snails (Lymnaea stagnalis) to form memory following training, whilst overcrowding and reduced calcium had a blocking effect.

Memory researchers turn to Beatles

Mar 10, 2008

A group of researchers in the British city of Leeds are using the music of The Beatles to study how musical memories impact an individual's identity.

Brain rehearsal time ensures lasting memory performance

Feb 14, 2012

University of Alberta researchers have established that the ability of the brain to rehearse or repeat electrical impulses may be absolutely critical in order to make a newly acquired memory more permanent.

Short-term memory ability may predict IQ

Jul 12, 2007

U.S. psychologists have found people with high IQs might be able to remember more than the four objects an average person can store in short-term memory.

Recommended for you

Timing clutch for greater sage-grouse

17 hours ago

(Phys.org) —It's an oft-repeated phrase that the early bird gets the worm. And, according to a collaborative study between the University of Maine and University of Nevada, Reno, it's also true that a greater sage-grouse ...

User comments : 5

Adjust slider to filter visible comments by rank

Display comments: newest first

Argiod
2.1 / 5 (7) Sep 27, 2012
I absolutely love the fact that chocolate, which got a bad rap a few decades ago, is now considered good food. Makes me feel like a kid again, when I knew chocolate was good for you. I didn't figure that anything that tasted that good, could be bad for you... on the understanding that too much of anything can be bad for you... thus the ancient saying about '...moderation in all things...' Even the Borgias knew that even a little bit of poison was good for you, in proper doses.
JGHunter
4.3 / 5 (3) Sep 27, 2012
The endorphin release alone, when used properly, must be evidence of benefits? You know the different between cheap horrible waxy chocolate and really, really good quality of chocolate, it really does feel great.
Telekinetic
2.4 / 5 (5) Sep 27, 2012
I might even give Escargot au Chocolat a try.
eric96
2 / 5 (4) Sep 27, 2012
Eating chocolate before studying improves memory, will tell GF haha
Mike_Massen
1 / 5 (4) Sep 27, 2012
Two snails on the ground watching cars drive by,
One snail says to the other, when I get rich I am going to have my own limousine with a big "S" painted on each side.
The other snail is puzzled and asks Why ?
Because then people can watch me drive past and say, "Hey ! look at that ess car go"

:-)