Meyer Bernd, Ansorge Cedrick, Nakagaki Toshiyuki
Faculty of Information Technology, Monash University, Melbourne, Victoria, Australia.
Institute for Geophysics and Meteorology, University of Cologne, Cologne, Germany.
PLoS One. 2017 Mar 29;12(3):e0172933. doi: 10.1371/journal.pone.0172933. eCollection 2017.
Self-organized mechanisms are frequently encountered in nature and known to achieve flexible, adaptive control and decision-making. Noise plays a crucial role in such systems: It can enable a self-organized system to reliably adapt to short-term changes in the environment while maintaining a generally stable behavior. This is fundamental in biological systems because they must strike a delicate balance between stable and flexible behavior. In the present paper we analyse the role of noise in the decision-making of the true slime mold Physarum polycephalum, an important model species for the investigation of computational abilities in simple organisms. We propose a simple biological experiment to investigate the reaction of P. polycephalum to time-variant risk factors and present a stochastic extension of an established mathematical model for P. polycephalum to analyze this experiment. It predicts that-due to the mechanism of stochastic resonance-noise can enable P. polycephalum to correctly assess time-variant risk factors, while the corresponding noise-free system fails to do so. Beyond the study of P. polycephalum we demonstrate that the influence of noise on self-organized decision-making is not tied to a specific organism. Rather it is a general property of the underlying process dynamics, which appears to be universal across a wide range of systems. Our study thus provides further evidence that stochastic resonance is a fundamental component of the decision-making in self-organized macroscopic and microscopic groups and organisms.
自组织机制在自然界中经常出现，并且已知能够实现灵活、自适应的控制和决策。噪声在这类系统中起着至关重要的作用：它能使自组织系统在保持总体稳定行为的同时，可靠地适应环境的短期变化。这在生物系统中至关重要，因为它们必须在稳定行为和灵活行为之间达成微妙的平衡。在本文中，我们分析了噪声在多头绒泡菌（Physarum polycephalum）决策过程中的作用，多头绒泡菌是研究简单生物体计算能力的重要模式物种。我们提出了一个简单的生物学实验来研究多头绒泡菌对时变风险因素的反应，并给出了一个针对多头绒泡菌的既定数学模型的随机扩展，以分析该实验。结果预测，由于随机共振机制，噪声能够使多头绒泡菌正确评估时变风险因素，而相应的无噪声系统则无法做到这一点。除了对多头绒泡菌的研究，我们还证明了噪声对自组织决策的影响并不局限于特定的生物体。相反，它是基础过程动力学的一个普遍属性，似乎在广泛的系统中都存在。因此，我们的研究进一步证明了随机共振是自组织宏观和微观群体及生物体决策的一个基本组成部分。
