Anyone who has ever eaten a spoiled meal and then spent hours of horror on the lotus knows that food poisoning is no fun. Afterwards, just the smell of the same dish is sometimes enough to revive the memory of the suffering experienced. The thought of the pain repeating itself can cause us to eliminate certain foods from our diet entirely – no matter how much we once loved them. The researchers believe that this aversion triggered by a negative experience could be quite similar to what they observed in snails. Yes, snails.
Snails like sugar. If they have him in front of their antennae, there’s no harm in it, he’ll be eaten. A team of researchers at the University of Sussex used conditioning training to wean the animals off this sweet craving. The results were published in the journal “Current Biology”. Instead of sugar, the snails now only want cucumber, and instead of sugar flash, the vitamin bomb. An effect that could also say something about the human brain. The scientists suspect that a kind of neurological switch has been switched on in the snails. The human brain works in a very similar way.
To drive the animals away from sugar cravings, the scientists used so-called aversive training. Whenever the snails were given sugar, the researchers lightly tapped their heads. A simple procedure that permanently spoiled the animals’ desire for a sweet meal. Little by little they even refused to eat sugar even though they were hungry.
The snail’s feeding cycle is controlled, among other things, by a neuron in the brain that ensures “that the snail doesn’t just eat everything and everyone,” explains Ildiko Kemenses, who leads the research team in Sussex. If a food stimulus such as sugar is present, the neuron that initiates large amounts of food is usually inhibited. This exact process seems to have been reversed by conditioning training. To put it simply: The eating impulse that the snail brain previously sent when it saw sugar does not occur.
Basically, the animals definitely had an appetite. The snails courageously bit into the cucumbers that the researchers presented to them as an alternative. And the desire for sugar also returned after the researchers completely removed the neurons from the animals. Which suggests that the neuron is necessary for the expression of the learned behavior. However, according to Kemenses, the researchers assume “that this is not everything that happens in the brain.”
“We believe that a similar switch may occur in the human brain, whereby certain groups of neurons reverse their activity according to the negative association with a particular food,” explains George Kemenes, Professor of Neuroscience at the University of Sussex and also part of the research team. This refers to negative associations such as food poisoning. The effect of the neuron in the snail brain on eating behavior is very similar to the inhibitory processes in the human brain that are normally responsible for curbing the urge to overeat. He says: “Snails provide us with a similar, if particularly simple, model of how the human brain works.”
Quelle: University of Sussex
