Physarum polycephalum is a single-celled organism; specifically, a slimy mold, a microscopic creature that thrives in cold and humid environments. It is an old acquaintance of researchers due to its ease of being cultivated, but now it has been discovered that it possesses other surprising qualities: it is capable of learning, a capacity only attributed to complex animals with nervous systems and brains.
To find out, a team from the Center de Recherches sur la Cognition Animale, in France, designed a curious experiment that lasted for nine days. The biologists put the ingenuity of two teams of Physarum polycephalum to the test . In order to get food, the first of them had to cross a kind of bridge impregnated with quinine or caffeine, bitter but harmless substances for them. The second group, the control group, also had to cross a catwalk, although this time devoid of the repulsive substances.
After six days, the French scientists observed that the microorganisms in the first team quickly crossed the bridge: they had gradually realized that neither caffeine nor quinine were harmful to them, a phenomenon known as “habituation .” If these creatures then went two days without contact with the bitter substances, they would regain their apprehension for them.
It is the first time that this type of rudimentary learning has been observed in living things without neurons , which could shed light on the propagation and survival strategies of pathogens such as viruses and bacteria. The study has been published in the journal Proceedings of the Royal Society B.
Photo: Physarum polycephalum. Credit: Audrey Dussutour (CNRS)
