How does smart slime mold "remember" food sources?

Polycephalum polycephalum Written | Lars Fischer (Lars Fischer) translation | Gong Cong Like all slime molds, Physarum polycephalum (Physarum polycephalum) has no brain and nervous system, but it can magically "remember "The location of the food in case of emergency.

Biophysicists Mirna Kramar and Karen Alim of the Max Planck Institute for Dynamics and Self-organization in Germany published a research paper describing this slime mold How to "remember" the location of food by changing its internal structure.

Although slime molds are composed of only staggered tubular structures and are a very simple organism, they can solve a variety of complex problems related to optimization, such as finding the shortest path through a maze.

Simple "stimulus-response" activity patterns (such as crawling in the direction of a certain molecular concentration or avoiding harmful mechanical stimuli) obviously cannot explain this ability of Physarum polycephalum.

For a long time, the mechanism by which Physarum polycephalum obtains and stores information has been an unsolved mystery.

A recent study published in the Proceedings of the National Academy of Sciences (PNAS) showed that when the body of Physarum polycephalum comes into contact with food, they release a substance.

This substance can soften the gel-like tube wall of the tubular network at the contact site, so that this part of the tubular structure can be thickened under the action of internal pressure.

The slime mold will expand along these thicker tubular structures, and the thinner tubular structures will be removed.

In this way, even if there is no food there, these thicker tubular structures can effectively record the location of the food before, because they directly affect the direction of movement of the slime mold.

At present, the researchers do not know the specific composition of this softening substance, but by modeling the change in pipe diameter, they found that it is likely to be a soluble substance that spreads through flow and diffusion.

The research team said that this mechanism is also common in other "life flow networks", such as the vascular system of vertebrates.

Hans-Günther Döbereiner, a physicist at the University of Bremen in Germany (who was not involved in the study), stated that Kramar and Alim "excellently proved the'memory' function of slime molds.
" Mechano-biological mechanism".

He said that in the future research on slime molds performing complex tasks, more attention needs to be paid to "molecular signals, the material properties and flow patterns of the cell fluid that regulates the behavior of slime molds.
"
Simon Garnier (Simon Garnier, who was not involved in this study), a biologist at the New Jersey Institute of Technology in the United States, believes that previous studies have investigated how slime molds encode past experience.
This study is based on previous studies.
Developed on the basis of work.

He said that the model proposed by the researchers "explains the slime mold's mechanism of'remembering' the food location".

Garnier added that this may contribute to the development of areas such as network optimization and routing algorithms, just as the ant colony has inspired us.

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