A neon yellow mucus form can store memories, even though it does not have a nervous system. Now scientists have found a new idea of how the brainless spot manages this impressive feat.
The unicellular organism, known as Physarum polycephalum, belongs to the taxonomic group Amoebozoa, the same group as amoebas, Live Science reported earlier. The spots may consist of one small cell with one nucleus, the cell’s control center, or several cells may merge to form one giant cell with many nuclei. These fused cells can grow up to tens of square inches (hundreds of square centimeters) in area.
When fused together, the large cells form a complex network of internal tubes; these tubes contract, similar to blood vessels, to push fluid and nutrients through the brainless spot.
The new study, published February 22 in the journal Proceedings of the National Academy of Sciences, shows that the diameters of these branch tubes can encode information, such as where the slime mold recently found food. When the stain finds food, it quickly reorganizes its tubular network, expands some tubes and shrinks others, and this architecture remains in place even after the stains have eaten the food.
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This basic form of memory can help mucus forms solve complex puzzles, such as fastest route to food or the shortest path through a maze, senior author Karen Alim, associate professor of biological physics at the Technical University of Munich, told WordsSideKick via email.
When P. polycephalum feel a snack in the area, by detecting chemicals that release the food, the tubes closest to the food begin to dilate. Meanwhile, tubes shrink further from the food and sometimes disappear completely and are reabsorbed by the mucus. The mucus form then creeps in the direction of the wide, expansive tubes and migrates until it swallows its snack.
But even after discarding every piece of food, the slime mold hangs from the cluster of thick tubes, leaving a long-lasting ‘imprint’ of where the food once was, the authors write. It determines how fluid flows through the entire network and influences in which direction the mucus form then moves. For example, when more food pops up near the thick, depressed tubes, the mucus form is already predisposed to spread in the direction, and the ‘depressed’ memory ‘is strengthened.
“In the brain, “stores our information by amplifying or attenuating connections between individual neurons, ‘a kind of nerve cell that sends electrical and chemical signals,’ Alim said. “Each additional impulse can amplify an existing strong connection.”
A similar – but simplified – process forms the formation of memory in mucus forms, she said.
And just like compounds in the brain, mucus-shaped “memories” can become weaker if not amplified, Alim adds. As tubes near food thicken, tubes far from food become thinner and may disappear. “Memories disappear as tubes retract and disappear” in the larger mucus form, Alim said. In this way, old memories of food can be overwritten as the stain migrates and is in search of new nutrients.
Previous studies of mucus forms have also indicated that the “network of mucus form adapts to external directions and that the network can be used as a reading of what the mucus form experienced,” said Audrey Dussutour, a researcher who specializes in cognitive processing in ants and mucus forms. at the University of Toulouse in France. The new study provides more evidence on how and why the tube network is being reorganized, Dussutour, who was not involved in the research, told WordsSideKick via email.
“The results remind me of trace networks in ants,” where feed ants lay down a trace of chemicals for other ants to follow, Dussutour added. As more ants follow the same trail and put down more chemicals, more ants will follow the well-worn route over another, less traveled, according to a 2005 Dussutour report in the magazine. Proceedings of the Royal Society B.
Although scientists know which pheromone ants secrete to lay their tracks, it is not certain which signal widens the tubes and shrinks others, Alim said.
Based on laboratory experiments and computer models of P. polycephalum, the authors suspect that the mucus form produces some soluble substance upon sensing food, and that the substance softens and stretches the tubes closest to the food. As the yellowish walls of the tubes stretch, some of the dust leaks into the larger network of tubes and becomes more diluted the further it moves. Therefore, tubes far from the food source received very little of the substance, if any, the authors explained.
‘Although there is evidence that this mysterious chemical drives the tube distribution, we unfortunately have no idea about its chemical composition,’ ‘Alim said.
In addition, ‘the next step is to ask how many memories can be stored in a network and whether we can transfer the mechanism to synthetic systems to build smart materials,’ Alim said. These smart materials will mimic the live stream networks that occur in slime forms and can be used to build soft body robots, for example according to a statement.
Originally published on Live Science.