Department of Anesthesiology, Weill Cornell Medical College, New York, NY 10065, USA.
Proc Natl Acad Sci U S A. 2012 Jun 26;109(26):10564-9. doi: 10.1073/pnas.1206894109. Epub 2012 Jun 7.
Typically one expects that the intervals between consecutive occurrences of a particular behavior will have a characteristic time scale around which most observations are centered. Surprisingly, the timing of many diverse behaviors from human communication to animal foraging form complex self-similar temporal patterns reproduced on multiple time scales. We present a general framework for understanding how such scale invariance may arise in nonequilibrium systems, including those that regulate mammalian behaviors. We then demonstrate that the predictions of this framework are in agreement with detailed analysis of spontaneous mouse behavior observed in a simple unchanging environment. Neural systems operate on a broad range of time scales, from milliseconds to hours. We analytically show that such a separation between time scales could lead to scale-invariant dynamics without any fine tuning of parameters or other model-specific constraints. Our analyses reveal that the specifics of the distribution of resources or competition among several tasks are not essential for the expression of scale-free dynamics. Rather, we show that scale invariance observed in the dynamics of behavior can arise from the dynamics intrinsic to the brain.
通常情况下，人们期望特定行为的连续发生之间的时间间隔会有一个特征时间尺度，大多数观察结果都集中在这个时间尺度周围。令人惊讶的是，从人类交流到动物觅食等许多不同行为的时间都呈现出复杂的自相似时间模式，这些模式可以在多个时间尺度上重现。我们提出了一个通用框架，用于理解非平衡系统中可能出现这种标度不变性的原因，包括那些调节哺乳动物行为的系统。然后，我们证明了这个框架的预测与在简单不变环境中观察到的自发小鼠行为的详细分析是一致的。神经系统在从毫秒到小时的广泛时间尺度上运作。我们分析表明，这种时间尺度之间的分离可能导致没有任何参数微调或其他特定于模型的约束的标度不变动力学。我们的分析表明，资源分配或几个任务之间竞争的具体细节对于表现出无标度动力学并不是必不可少的。相反，我们表明，行为动力学中观察到的标度不变性可以源自大脑内部的动力学。
