Slime Mold Smarty Pants


A form of spatial memory helps a brainless slime mold navigate complex environments, hinting at the possible origins of memory in higher organisms.

The slime mold Physarum polycephalum remembers where it’s been, allowing the single-cell amoeboid to more efficiently navigate its environment. The key, according to a study published yesterday (October 8) in Proceedings of the National Academy of Sciences, a kind of externalized spatial memory system, based on the trail of translucent slime it leaves in its wake, that allows the organism to recognize and avoid already-explored areas.

“It doesn’t have a brain. It doesn’t even have a neuron. It has to do everything with just one cell,” Audrey Dussutour, a collective behavior specialist at France’s National Center for Scientific Research, told Wired Science. “The easiest way to have a memory of where you’ve been is to leave something behind.”

When Dussutour and her colleagues noticed that foraging P. polycephalum do not often cross earlier paths, they decided to put the slime mold to the test. The researchers presented P. polycephalum with an agarose-floored Y-maze with food at the end of both arms, but in one of the arms, they covered the agar with extracellular slime; 39 of 40 went down the arm with blank agar, avoiding the slime. When both arms contained slime or both arms lacked slime, P. polycephalum showed no preference.

Written By: Jef Akst
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  1. Here is some youtube footage of Physarum polycephalum  negotiating a maze.
    I think our species’ days are numbered.

    P.S. Can I just say that, in this time of international turmoil, religious upheaval, holy wars, and a presidential election that may decide the fate of the entire human race, it’s gratifying to know that I can get away from serious stuff like that and come onto Richard Dawkins’ website where I can post a comment about some slime that nobody in the known universe gives a holy crap about.

  2. It is very sad, and worrying, that an awful lot of people ‘in the known universe’ don’t only’ give a holy crap about some slime ‘ but also about all the other issues you mention.  

  3. This isn’t news. I gave a talk in Oxford on how their memories work years ago. Long story short: mechanical memristance.

  4. The mold evolved to solve mazes for a practical reason.  How do I maintain contact with food sources with minimal interconnection?  It has a sort Quantum-computing-like way of brute force approach — try all possibilities and wean out the less desirable solutions.  It is a completely different mechanism than a rat uses.  

    I suspect using its general strategy might be a way of attacking some computer problems when you have plenty of CPUs.

  5. Sponge Bob Square Pants wipes up Slime Mold Smarty Pants – film at 10:00.

    They call me Mello Yellow…

  6. How come a single-cell life form can show more logic and purpose than a human believer?

    It will search all available avenues for knowledge of its universe; avoiding the pointless going-around-in-circles covering the same old ground when there is no evidence to support that activity.

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