Amoeba-based computing for traveling salesman problem: Long-term correlations between spatially separated individual cells of Physarum polycephalum

Liping Zhu, Masashi Aono, Song Ju Kim, Masahiko Hara

Research output: Contribution to journalArticle

32 Citations (Scopus)

Abstract

A single-celled, multi-nucleated amoeboid organism, a plasmodium of the true slime mold Physarum polycephalum, can perform sophisticated computing by exhibiting complex spatiotemporal oscillatory dynamics while deforming its amorphous body. We previously devised an " amoeba-based computer (ABC)" to quantitatively evaluate the optimization capability of the amoeboid organism in searching for a solution to the traveling salesman problem (TSP) under optical feedback control. In ABC, the organism changes its shape to find a high quality solution (a relatively shorter TSP route) by alternately expanding and contracting its pseudopod-like branches that exhibit local photoavoidance behavior. The quality of the solution serves as a measure of the optimality of which the organism maximizes its global body area (nutrient absorption) while minimizing the risk of being illuminated (exposure to aversive stimuli). ABC found a high quality solution for the 8-city TSP with a high probability. However, it remains unclear whether intracellular communication among the branches of the organism is essential for computing. In this study, we conducted a series of control experiments using two individual cells (two single-celled organisms) to perform parallel searches in the absence of intercellular communication. We found that ABC drastically lost its ability to find a solution when it used two independent individuals. However, interestingly, when two individuals were prepared by dividing one individual, they found a solution for a few tens of minutes. That is, the two divided individuals remained correlated even though they were spatially separated. These results suggest the presence of a long-term memory in the intrinsic dynamics of this organism and its significance in performing sophisticated computing.

Original languageEnglish
Pages (from-to)1-10
Number of pages10
JournalBioSystems
Volume112
Issue number1
DOIs
Publication statusPublished - 2013 Apr
Externally publishedYes

Fingerprint

Physarum polycephalum
Amoeba
Traveling salesman problem
Travelling salesman problems
Computing
Cell
Branch
Optical Feedback
Memory Term
Myxomycetes
Nutrients
Feedback Control
Optical feedback
Optimality
Pseudopodia
Aptitude
Absorption
Plasmodium
Long-Term Memory
Maximise

Keywords

  • Chaos
  • Combinatorial optimization
  • Coupled oscillators
  • Natural computing
  • Neural network
  • Spatiotemporal dynamics

ASJC Scopus subject areas

  • Statistics and Probability
  • Modelling and Simulation
  • Biochemistry, Genetics and Molecular Biology(all)
  • Applied Mathematics

Cite this

Amoeba-based computing for traveling salesman problem : Long-term correlations between spatially separated individual cells of Physarum polycephalum. / Zhu, Liping; Aono, Masashi; Kim, Song Ju; Hara, Masahiko.

In: BioSystems, Vol. 112, No. 1, 04.2013, p. 1-10.

Research output: Contribution to journalArticle

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