Emergence of long timescales and stereotyped behaviors in Caenorhabditis elegans
Emergence of long timescales and stereotyped behaviors in Caenorhabditis elegans
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DOI：
10.1073/pnas.1007868108
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发表时间：
2011-05-03
影响因子：
11.1
通讯作者：
Bialek, William
中科院分区：
文献类型：
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作者：
Stephens, Greg J.;de Mesquita, Matthew Bueno;Bialek, William
动物的行为通常可以分解成离散的、定型的元素，在时间上被很好地分开。在一个模型中，这种行为是由特定的命令触发的;在极端的情况下，行为的离散性可以追溯到单个命令神经元中动作电位的离散性。在这里，我们使用线虫的爬行行为的秀丽隐杆线虫来证明相反的观点，其中离散性，刻板性和长时间尺度出现的集体动态的行为本身。在以前的工作中，我们发现，作为C。当线虫爬行时，它的身体在一个“形状空间”中移动，在这个空间中，四维捕获了大约95%的身体形状变化。在这里，我们表明，在这个形状空间内的随机动力学预测吸引子之间的过渡对应于爬行方向的突然逆转。在没有自由参数的情况下，我们推断的随机动力学系统产生的反转时间尺度和刻板的轨迹与实验观察结果非常一致。我们使用的随机动力学表明，噪声幅度系统地降低，随着远离食物的时间增加，导致更长的向前爬行，并表明蠕虫可以使用噪声来修改它们的运动行为。
Animal behaviors often are decomposable into discrete, stereotyped elements, well separated in time. In one model, such behaviors are triggered by specific commands; in the extreme case, the discreteness of behavior is traced to the discreteness of action potentials in the individual command neurons. Here, we use the crawling behavior of the nematode Caenorhabditis elegans to demonstrate the opposite view, in which discreteness, stereotypy, and long timescales emerge from the collective dynamics of the behavior itself. In previous work, we found that as C. elegans crawls, its body moves through a "shape space" in which four dimensions capture approximately 95% of the variance in body shape. Here we show that stochastic dynamics within this shape space predicts transitions between attractors corresponding to abrupt reversals in crawling direction. With no free parameters, our inferred stochastic dynamical system generates reversal timescales and stereotyped trajectories in close agreement with experimental observations. We use the stochastic dynamics to show that the noise amplitude decreases systematically with increasing time away from food, resulting in longer bouts of forward crawling and suggesting that worms can use noise to modify their locomotory behavior.