Path finding by tube morphogenesis in an amoeboid organism

Nakagaki, Toshiyuki; Yamada, Hiroyasu; Tóth, Ágota

doi:10.1016/s0301-4622(01)00179-x

Cited by 264 publications

(196 citation statements)

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“…The control of the organism's body shape in response to volume of available food follows a previously established rule: the number of remaining paths is larger when less food is provided to a fixed amount of plasmodial inoculum (see Nakagaki et al, 2001 for details). This behavior is considered trade-off between the physiological requirements of moving towards the FSs in order to consume the food and connecting the two FSs to maintain intracellular communication.…”

Section: Discussionmentioning

confidence: 99%

“…Almost the entire plasmodium was taken up in this accumulation, covering each source in order to absorb nutrients, and only a few tubes remained connecting the separated components of the plasmodium. It should be noted that the connecting path traced the shortest route to the food sources even in the complex geometry of a maze (Nakagaki et al, 2000a;Nakagaki et al, 2001). This phenomenon can be applied to both path-finding in a maze and path selection in a transport network.…”

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confidence: 99%

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A mathematical model for adaptive transport network in path finding by true slime mold

Tero

Kobayashi

Nakagaki

2007

Journal of Theoretical Biology

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369

354

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We describe here a mathematical model of the adaptive dynamics of a transport network of the true slime mold Physarum polycephalum, an amoeboid organism that exhibits path-finding behavior in a maze. This organism possesses a network of tubular elements, by means of which nutrients and signals circulate through the plasmodium. When the organism is put in a maze, the network changes its shape to connect two exits by the shortest path. This process of path-finding is attributed to an underlying physiological mechanism: a tube thickens as the flux through it increases. The experimental evidence for this is, however, only qualitative. We constructed a mathematical model of the general form of the tube dynamics. Our model contains a key parameter corresponding to the extent of the feedback regulation between the thickness of a tube and the flux through it. We demonstrate the dependence of the behavior of the model on this parameter.

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

A mathematical model for adaptive transport network in path finding by true slime mold

Tero

Kobayashi

Nakagaki

2007

Journal of Theoretical Biology

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369

354

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“…The effects of two separate food sources have previously been studied, and minimizing the total length (TL) of the network was found to have an important role (Nakagaki et al 2000a(Nakagaki et al , 2001). This network shape of the body enables certain physiological requirements to be met: (i) absorption of nutrients from food souces as efficiently as possible because almost all the body mass stays at the food sources to enable absorption; (ii) maintenance of the connectivity and intracellular communication throughout the organism; and (iii) meeting the constraint of limited resource of body mass.…”

Section: Introductionmentioning

confidence: 99%

Obtaining multiple separate food sources: behavioural intelligence in the Physarum plasmodium

Nakagaki

Kobayashi

Nishiura

et al. 2004

Proc. R. Soc. Lond. B

204

144

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To evaluate performance in a complex survival task, we studied the morphology of the Physarum plasmodium transportation network when presented with multiple separate food sources. The plasmodium comprises a network of tubular elements through which chemical nutrient, intracellular signals and the viscous body are transported and circulated. When three separate food sources were presented, located at the vertices of a triangle, the tubular network connected them via a short pathway, which was often analogous to the mathematically shortest route known as Steiner's minimum tree (SMT). The other common network shape had high fault tolerance against accidental disconnection of the tubes and was known as cycle (CYC). Pattern selection appeared to be a bistable system involving SMT and CYC. When more than three food sources were presented, the network pattern tended to be a patchwork of SMT and CYC. We therefore concluded that the plasmodium tube network is a well designed and intelligent system.

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“…Although the brain has evolved to perform this specific function, information processing is possible without a brain, and organisms as simple as amoebae are much more intelligent than generally thought. For example, the true slime mold Physarum polycephalum can solve a maze and certain geometrical puzzles, in order to satisfy its needs for efficient absorption of nutrients and intracellular communication [1][2][3][4]. Thus, from an evolutionary perspective, information processing by unicellular organisms might represent a simple precursor of braindependent higher functions.…”

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confidence: 99%

Amoebae Anticipate Periodic Events

et al. 2008

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When plasmodia of the true slime mold Physarum were exposed to unfavorable conditions presented as three consecutive pulses at constant intervals, they reduced their locomotive speed in response to each episode. When the plasmodia were subsequently subjected to favorable conditions, they spontaneously reduced their locomotive speed at the time when the next unfavorable episode would have occurred. This implied the anticipation of impending environmental change. We explored the mechanisms underlying these types of behavior from a dynamical systems perspective. DOI: 10.1103/PhysRevLett.100.018101 PACS numbers: 87.17.Aa, 87.18.Hf, 87.23.Kg Information processing is an interesting component of biological systems. Although the brain has evolved to perform this specific function, information processing is possible without a brain, and organisms as simple as amoebae are much more intelligent than generally thought. For example, the true slime mold Physarum polycephalum can solve a maze and certain geometrical puzzles, in order to satisfy its needs for efficient absorption of nutrients and intracellular communication [1][2][3][4]. Thus, from an evolutionary perspective, information processing by unicellular organisms might represent a simple precursor of braindependent higher functions. Anticipating and recalling events are two such functions; however, the way in which they self-organize has so far remained unknown.P. polycephalum is a useful model organism for studying behavioral intelligence [5]. Its plasmodium is a large aggregate of protoplasm that possesses an intricate network of tubular structures, and can crawl over agar plates at a speed of approximately 1 cm=h at room temperature. In order to investigate primitive forms of brain function (such as learning, memory, anticipation, and recall), here we have examined the rhythmicity of cell behaviors [6,7] and the adaptability of cells to periodic environmental changes [8,9]. Our approach was to expose organisms to periodic changes in ambient conditions and to observe their behavioral responses. As there has been much controversy in recent years over the existence of nonhuman intelligence [10 -13], this subject requires evaluation by modern scientific techniques.Here we show that an amoeboid organism can anticipate the timing of periodic events. Moreover, we explore the mechanisms underlying this behavior from a dynamical systems perspective. Our results hint at the cellular origins of primitive intelligence, and imply that simple dynamics might be sufficient to explain its emergence.A large plasmodium of P. polycephalum was cultured with oat flakes in a trough (25 35 cm 2 ) on an agar plate under dim light. The tip region of an extended front was removed and placed in a narrow lane (0:5 28 cm 2 ) at 26 C and 90% humidity (hereafter referred to as standard conditions; all experiments were conducted under these ambient conditions unless otherwise specified). The organism migrated along the lane, and the position of its tip was measured every 10 min. After migrat...

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Path finding by tube morphogenesis in an amoeboid organism

Cited by 264 publications

References 16 publications

A mathematical model for adaptive transport network in path finding by true slime mold

A mathematical model for adaptive transport network in path finding by true slime mold

Obtaining multiple separate food sources: behavioural intelligence in the Physarum plasmodium

Amoebae Anticipate Periodic Events

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