Functional advantages of Levy walks emerging near a critical point
Functional advantages of Levy walks emerging near a critical point
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DOI：
10.1073/pnas.2001548117
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发表时间：
2020-09-29
影响因子：
11.1
通讯作者：
Abe, Masato S.
中科院分区：
文献类型：
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作者：
Abe, Masato S.
一种特殊的随机漫步，即所谓的利维漫步，已经在各种生物体中被观察到，从细胞、昆虫、鱼类、鸟类到哺乳动物，包括人类。虽然它们的流行被认为是自然选择的结果，以提高搜索效率，但一些研究结果表明，利维行走也可能是与环境相互作用产生的副现象。因此，为什么它们在生物运动中很常见仍然是一个悬而未决的问题。基于一些证据表明Levy步行是在大脑中自发产生的，并且Levy步行的幂律分布可以在临界点出现，我们假设Levy步行的优势可能会因临界而增强。然而，人们对Levy步行的功能优势知之甚少。在这里，我们对运动产生的非线性系统进行了建模，并表明在临界点附近出现的Levy步行具有编码信息的最佳动态范围。这一发现表明，利维步法可以根据环境刺激的大小改变运动轨迹。然后，我们证明了Levy行走的高度灵活性可以根据外部线索的性质切换利用/探索。最后，我们分析了自由运动的果蝇幼虫的运动轨迹，实证表明Levy行走可能出现在一个临界点附近，并且具有大的动态范围和高的灵活性。我们的研究结果表明，通常观察到的Levy行走出现在一个临界点附近，可以在这些功能优势的基础上解释。
A special class of random walks, so-called Levy walks, has been observed in a variety of organisms ranging from cells, insects, fishes, and birds to mammals, including humans. Although their prevalence is considered to be a consequence of natural selection for higher search efficiency, some findings suggest that Levy walks might also be epiphenomena that arise from interactions with the environment. Therefore, why they are common in biological movements remains an open question. Based on some evidence that Levy walks are spontaneously generated in the brain and the fact that power-law distributions in Levy walks can emerge at a critical point, we hypothesized that the advantages of Levy walks might be enhanced by criticality. However, the functional advantages of Levy walks are poorly understood. Here, we modeled nonlinear systems for the generation of locomotion and showed that Levy walks emerging near a critical point had optimal dynamic ranges for coding information. This discovery suggested that Levy walks could change movement trajectories based on the magnitude of environmental stimuli. We then showed that the high flexibility of Levy walks enabled switching exploitation/exploration based on the nature of external cues. Finally, we analyzed the movement trajectories of freely moving Drosophila larvae and showed empirically that the Levy walks may emerge near a critical point and have large dynamic range and high flexibility. Our results suggest that the commonly observed Levy walks emerge near a critical point and could be explained on the basis of these functional advantages.