Component of chocolate and wine enhances memories -- in snails

A component of chocolate, wine and green tea can enhance memories -- in snails, at least.

A new study, released Wednesday in the Journal of Experimental Biology, showed that modest concentrations of the flavonoid epicatechin caused snails’ memories to last longer and be harder to overwrite.

In nature, flavonoids are found in many species of plants, often adding color to plant skin by serving as pigments. They have long been studied as possible cancer fighters and cognitive enhancers because they have beneficial antioxidant effects on cells in a dish. But the concentrations tested in those studies were much higher than are generally possible to study in live animals. When researchers have studied flavonoids in animals, the results have been lackluster.

In the new study, researchers from the University of Calgary studied whether exposing snails to roughly the same amount of epicatechin humans regularly consume would enhance their memories. When the snails are in normal water, they breathe through their skin. But when the oxygen level in the water becomes low, the snails have a backup: They extend a breathing tube above the water level, like a built-in snorkel. Researchers have learned that they can actually teach the snails to keep this tube shut even in deoxygenated water by tapping it lightly.

Usually, snails remember to keep the tube shut for only about three hours after it is tapped. But the snails exposed to epicatechin remembered for a full day. And when the researchers added a second training session -- which extended the length of the control snails’ memories to a day -- the flavonoid-sucking snails remembered to keep their snorkel closed for 72 hours.

So the memories lasted longer. But were they also harder to get rid of?

The researchers tested this through a process called extinction -- basically, putting the snails in the same situation in which they were previously poked, but without the pokes. The control snails demonstrated extinction after only one training session. But snails that had been given epicatechin required three, showing that their memories were actually harder to replace.

The researchers believe that studies in the snail will allow them to pin down the exact molecular workings of epicatechin, determining what its role is in the central nervous system that leads to enhanced memories.

Whether that research translates to more standard lab animals like mice -- let alone humans -- remains to be seen.

You can read a summary of the snail study here.

Return to the Science Now blog.