Katsov Alexander Y, Freifeld Limor, Horowitz Mark, Kuehn Seppe, Clandinin Thomas R
Department of Neurobiology, Stanford University, Stanford, United States.
Department of Electrical Engineering, Stanford University, Stanford, United States.
Elife. 2017 Jul 25;6:e26410. doi: 10.7554/eLife.26410.
The function of the brain is unlikely to be understood without an accurate description of its output, yet the nature of movement elements and their organization remains an open problem. Here, movement elements are identified from dynamics of walking in flies, using unbiased criteria. On one time scale, dynamics of walking are consistent over hundreds of milliseconds, allowing elementary features to be defined. Over longer periods, walking is well described by a stochastic process composed of these elementary features, and a generative model of this process reproduces individual behavior sequences accurately over seconds or longer. Within elementary features, velocities diverge, suggesting that dynamical stability of movement elements is a weak behavioral constraint. Rather, long-term instability can be limited by the finite memory between these elementary features. This structure suggests how complex dynamics may arise in biological systems from elements whose combination need not be tuned for dynamic stability.
如果没有对大脑输出的准确描述，就不太可能理解大脑的功能，然而运动元素的性质及其组织仍然是一个悬而未决的问题。在这里，使用无偏标准从果蝇行走的动力学中识别出运动元素。在一个时间尺度上，行走的动力学在数百毫秒内是一致的，从而可以定义基本特征。在更长的时间段内，行走可以很好地用由这些基本特征组成的随机过程来描述，并且这个过程的生成模型能够在数秒或更长时间内准确地再现个体行为序列。在基本特征中，速度会发散，这表明运动元素的动态稳定性是一种较弱的行为约束。相反，长期的不稳定性可以通过这些基本特征之间有限的记忆来限制。这种结构表明了复杂的动力学是如何在生物系统中从那些其组合不需要为动态稳定性而进行调整的元素中产生的。
