We tend to see them as rudimentary beings, devoid of inner life. And yet, experiments demonstrate that the behavior, faced with small electric shocks, of C. elegans, the star nematode of the labs, displays all the characteristics expected for one of the most fundamental emotions: fear.
Hervé Poirier, editor-in-chief of the scientific magazine Epsiloon, explains to us today that researchers have just noticed that even small worms one millimeter long feel emotions.
franceinfo: Recent experiments on a very small worm demonstrate that C. elegans displays the characteristics of an emotion? Explain to us
Hervé Poirier: It’s not just any worm. It is C. elegansa big star in the labs, known to have a nervous system of 302 neurons – compared to 86 billion in the human brain. A team from Nagoya University, in Japan, subjected a few specimens to a somewhat unpleasant experiment. They applied electric shocks to them, via alternating current, with a voltage of 30 V and an intensity of 80 mA, for a few seconds.
And these researchers observed an escape reaction in the little worms: they accelerate their movement speed by a factor of 2 to 3 for 1 min 30, abandoning the bacterial broths present in their path (a dish that these great gourmands love). . And the more the voltage and the application time increase, the stronger the reaction. For Japanese researchers, this proves one thing: C. elegans is gifted with emotion,n this case, he feels fear.
How can this be called an emotion?
To be recognized as such, the reaction to a stimulus must combine four characteristics: the reaction must last, that it corresponds has a feeling – positive or negative – that it is proportional to the intensity of the stimulus, and that it provokes responses that are not directly linked to it. This is exactly what is happening here, with our little nematodes.
By analyzing the activity of neurons, the researchers found that, during flight, there is persistent activity of a specific set of neurons, unrelated to direct stimulation of the motor system. His flight reaction is clearly negative. It is proportional to that of the shock, et this affects his normally voracious appetite. For researchers, not at all, it’s fear.
And is it a surprise?
Yes. vs.elegans was hitherto considered to be devoid of such inner feelings. This amplifies the uneasiness about animal testing a little. The most spectacular experiments carried out on C.elegans consist of cutting off its head only to see that it grows back.
Above all, it shows that emotion is not the noble attribute of beings gifted with sophisticated cognition. It takes a lot of attention to have empathy. But bodies as rudimentary as those of these little worms are also capable of great sensitivity.