Collective phenomena fascinate by the emergence of order in systems composed of a myriad of small entities. They are ubiquitous in nature and can be found over a vast range of scales in physical and biological systems. Their key feature is the seemingly effortless emergence of adaptive collective behavior that cannot be trivially explained by the properties of the system's individual components. This perspective focuses on recent insights into the similarities of correlations for two apparently disparate phenomena: flocking in animal groups and neuronal ensemble activity in the brain. We first will summarize findings on the spontaneous organization in bird flocks and macro-scale human brain activity utilizing correlation functions and insights from critical dynamics. We then will discuss recent experimental findings that apply these approaches to the collective response of neurons to visual and motor processing, i.e., to local perturbations of neuronal networks at the meso- and microscale. We show how scale-free correlation functions capture the collective organization of neuronal avalanches in evoked neuronal populations in nonhuman primates and between neurons during visual processing in rodents. These experimental findings suggest that the coherent collective neural activity observed at scales much larger than the length of the direct neuronal interactions is demonstrative of a phase transition and we discuss the experimental support for either discontinuous or continuous phase transitions. We conclude that at or near a phase-transition neuronal information can propagate in the brain with similar efficiency as proposed to occur in the collective adaptive response observed in some animal groups.

中文翻译：

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动物群和脑网络中的无标度动力学

由无数小实体组成的系统中秩序的出现使集体现象着迷。它们在自然界中无处不在，可以在物理和生物系统的广泛范围内找到。它们的关键特征是适应性集体行为的出现似乎毫不费力，无法用系统各个组件的属性来简单解释。这一观点侧重于最近对两种明显不同现象的相关性相似性的见解：动物群体中的聚集和大脑中的神经元集合活动。我们首先将利用相关函数和关键动力学的见解总结关于鸟群自发组织和宏观人类大脑活动的发现。然后我们将讨论最近的实验结果，这些方法将这些方法应用于神经元对视觉和运动处理的集体反应，即在中观和微观尺度上神经元网络的局部扰动。我们展示了无标度相关函数如何在非人类灵长类动物的诱发神经元群体中以及啮齿动物视觉处理过程中的神经元之间捕获神经元雪崩的集体组织。这些实验结果表明，在远大于直接神经元相互作用长度的尺度上观察到的连贯集体神经活动证明了相变，我们讨论了对不连续或连续相变的实验支持。