The memory of past events allows us to make more informed decisions about the future. Although there is no nervous system, researchers at the Max Planck Institute for Dynamics and Self-Organization (MPIDS) and the Technical University of Munich (TUM) have determined the basis for the formation of memories in the mucus-like long Physarum polycephalum.
The ability to store and restore information provides clear advantages to organisms when looking for food or avoiding harmful environments, and has traditionally been associated with organisms with a nervous system. A new study written by Mirna Kramar (MPIDS) and Professor Karen Alim (TUM and MPIDS) challenges this view by revealing the amazing ability of highly dynamic single-celled organisms to store and retrieve information about their environment.
Physarum polycephalum has troubled researchers for decades. Existing at the crossroads between the animal and plant kingdoms and the fungus kingdom, this unique organism provides insights into the early evolutionary history of eukaryotes. Its body is a huge single cell composed of interconnected tubes forming a complex network. This single amoeba cell may extend several centimeters or even several meters, making it the largest cell on earth. Guinness World Records.
Slime mold has the amazing ability to solve complex problems, such as finding the shortest path in a maze, and thus acquires the “smart” attribute, which arouses the interest of the research community and raises the most basic level of decision-making problems in life. Given that Physarum’s tubular network is constantly undergoing rapid reorganization (making its tubes continuously growing and decomposing), and its complete lack of organizational center, its decision-making ability is particularly fascinating. Researchers have discovered that this organism weaves food memories directly into the structure of the network-like body and uses the stored information when making future decisions.
Decisions are guided by memory
Karen Alim, head of the biophysics and morphogenesis research group of the MPIDS and TUM biological network theory professor, said: “It is very exciting to develop a project from simple experimental observations. After eating for a long time, the food is observed The source has obvious imprints on the thicker and thinner pipe network patterns of the network. Considering that P. polycephalum has a highly dynamic network reorganization, the persistence of this imprint has led to the idea that the network architecture itself can Used to remember the past. But first we need to explain the mechanism of brand formation.”
To find out what is happening, the researchers combined microscopic observations of the adaptability of the tubular network with theoretical models. Contact with food triggers the release of a chemical substance that spreads from the location where the food is found throughout the organism and softens the ducts in the network, thereby redirecting the migration of the entire organism to the food.
The first author of the study, Mirna Kramar, said: “The softening is where the existing imprints of the previous food sources come into play, and the information is stored and retrieved.” “Past feeding events are embedded in the hierarchy of pipe diameters, especially It is in the arrangement of thick and thin pipes in the pipe network. For the softening chemicals that are now being transported, the thick pipes in the pipe network act as a highway in the transportation network and can quickly migrate throughout the organism. Network The previous encounters in the architecture are the decisions that determine the future direction of the migration.”
General principles inspire design
The author emphasizes that given the simplicity of this active network, Physarum’s ability to form memories is fascinating. “It’s worth noting that the organism relies on this simple mechanism but controls it in such a delicate way. These results provide an important problem for understanding the behavior of this ancient organism, while pointing to the general Sex. The basic principle of behavior. We envision the potential applications of our findings in designing smart materials and building soft robots that can navigate in complex environments.”
Testing the influence of “noise” on the decision-making ability of slime mold
Mirna Kramar et al. The code memory in the pipe diameter level of the live stream network, Proceedings of the National Academy of Sciences (2021). DOI: 10.1073 / pnas.2007815118
Courtesy of the Max Planck Institute
Citation: Researchers have discovered a single-celled slime mold without a nervous system, which can remember the location of food (February 23, 2021), from February 23, 2021 from https://phys.org/news/2021 -02-single-celled-slime-mold- nuclear-food.html
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