Capturing the continuous complexity of behaviour inCaenorhabditis elegans
Capturing the continuous complexity of behaviour inCaenorhabditis elegans
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DOI：
10.1038/s41567-020-01036-8
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发表时间：
2020-10-05
期刊：
影响因子：
19.6
通讯作者：
Stephens, Greg J.
中科院分区：
文献类型：
--
作者：
Ahamed, Tosif;Costa, Antonio C.;Stephens, Greg J.
动物行为的特点是重复的动作，这可能很难定量分析。在这里，作者应用基于动力系统理论的数据驱动框架来描述线虫行为，并通过确定性混沌动力学来解释其复杂性。动物行为通常通过主观的、不完整的变量来量化，这些变量掩盖了基本的动力学。在这里，我们开发了一个最大的预测行为状态空间，从多变量测量，在其中的完整的瞬时状态被平滑地展开为短时间姿势序列的组合。在关闭的食物行为的蛔虫秀丽隐杆线虫，我们发现了一个低维状态空间占主导地位的三套循环轨迹对应的蠕虫的基本定型图案：向前，向后和转向运动。我们在觅食蠕虫和npr-1突变体的食物行为中发现了类似的结果。与此相反，这种广泛的刻板印象，我们发现在存在的局部不稳定的动力学与确定性的混沌签名的变化：一个集合的不稳定的周期轨道连同一个积极的最大李雅普诺夫指数。完整的李雅普诺夫谱是对称的，正的，混沌指数驱动的负，耗散指数驱动的刻板平衡的变化。这种对称性表明了蠕虫运动控制背后的阻尼驱动哈密顿动力学。
Animal behaviour is characterized by repeated movements which can be difficult to analyse quantitatively. Here, the authors apply a data-driven framework based on theory of dynamical systems to characterize nematode behaviour and explain its complexity through deterministic chaotic dynamics.Animal behaviour is often quantified through subjective, incomplete variables that mask essential dynamics. Here, we develop a maximally predictive behavioural-state space from multivariate measurements, in which the full instantaneous state is smoothly unfolded as a combination of short-time posture sequences. In the off-food behaviour of the roundwormCaenorhabditis elegans, we discover a low-dimensional state space dominated by three sets of cyclic trajectories corresponding to the worm's basic stereotyped motifs: forward, backward and turning locomotion. We find similar results in the on-food behaviour of foraging worms andnpr-1mutants. In contrast to this broad stereotypy, we find variability in the presence of locally unstable dynamics with signatures of deterministic chaos: a collection of unstable periodic orbits together with a positive maximal Lyapunov exponent. The full Lyapunov spectrum is symmetric with positive, chaotic exponents driving variability balanced by negative, dissipative exponents driving stereotypy. The symmetry is indicative of damped-driven Hamiltonian dynamics underlying the worm's movement control.