Slime mold uses an externalized spatial “memory” to navigate in complex environments |
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Authors: | Chris R Reid Tanya Latty Audrey Dussutour Madeleine Beekman |
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Institution: | aBehaviour and Genetics of Social Insects Laboratory, School of Biological Sciences, and;bCentre for Mathematical Biology, University of Sydney, Sydney, NSW 2006, Australia; and;cCentre de Recherches sur la Cognition Animale, UMR 5169 Centre National de la Recherche Scientifique, Université Toulouse III, 31062 Toulouse, France |
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Abstract: | Spatial memory enhances an organism’s navigational ability. Memory typically resides within the brain, but what if an organism has no brain? We show that the brainless slime mold Physarum polycephalum constructs a form of spatial memory by avoiding areas it has previously explored. This mechanism allows the slime mold to solve the U-shaped trap problem—a classic test of autonomous navigational ability commonly used in robotics—requiring the slime mold to reach a chemoattractive goal behind a U-shaped barrier. Drawn into the trap, the organism must rely on other methods than gradient-following to escape and reach the goal. Our data show that spatial memory enhances the organism’s ability to navigate in complex environments. We provide a unique demonstration of a spatial memory system in a nonneuronal organism, supporting the theory that an externalized spatial memory may be the functional precursor to the internal memory of higher organisms. |
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Keywords: | extracellular slime protist reactive navigation amoeboid organism |
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