Single-cell analysis of habituation in Stentor coeruleus
Single-cell analysis of habituation in Stentor coeruleus
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DOI：
10.1016/j.cub.2022.11.010
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发表时间：
2023-01-23
期刊：
影响因子：
9.2
通讯作者：
Marshall，Wallace F.
中科院分区：
文献类型：
--
作者：
Rajan，Deepa;Makushok，Tatyana;Marshall，Wallace F.
尽管学习通常被视为具有复杂神经系统的生物体的独特特征，但单细胞生物体也展示了学习的基本形式。巨大的纤毛蓝肌对机械刺激的反应是收缩成紧凑的形状，推测这是一种防御机制。当Stentorcell以恒定的力水平反复受到刺激时，它会学会忽略这种刺激，但仍然会对更强的刺激做出反应。先前关于压力习惯化的研究报告了一种分级的反应，这表明细胞通过一系列连续的反应概率进行转换。通过使用自动仪器传递校准刺激来分析单个细胞，我们发现习惯化是通过每个细胞内收缩概率的单个阶梯式开关发生的，而群体中的分级反应来自于单个细胞中开关时间的随机分布。这种阶梯式响应使得Stentor行为可以用一个简单的两态模型来表示，该模型的参数可以从实验测量中估计出来。我们发现，转换率取决于刺激力，也取决于刺激间隔时间。测量相同细胞对相同刺激的行为的能力使我们能够量化单个细胞之间的功能异质性。综上所述，我们的结果表明，Stentor的行为是由两状态随机机器控制的，其转换率对输入刺激的时间序列性质很敏感。
Although learning is often viewed as a unique feature of organisms with complex nervous systems, single-celled organisms also demonstrate basic forms of learning. The giant ciliateStentor coeruleusresponds to mechanical stimuli by contracting into a compact shape, presumably as a defense mechanism. When aStentorcell is repeatedly stimulated at a constant level of force, it will learn to ignore that stimulus but will still respond to stronger stimuli. Prior studies of habituation inStentorreported a graded response, suggesting that cells transition through a continuous range of response probabilities. By analyzing single cells using an automated apparatus to deliver calibrated stimuli, we find that habituation occurs via a single step-like switch in contraction probability within each cell, with the graded response in a population arising from the random distribution of switching times in individual cells. This step-like response allowsStentorbehavior to be represented by a simple two-state model whose parameters can be estimated from experimental measurements. We find that transition rates depend on stimulus force and also on the time between stimuli. The ability to measure the behavior of the same cell to the same stimulus allowed us to quantify the functional heterogeneity among single cells. Together, our results suggest that the behavior ofStentoris governed by a two-state stochastic machine whose transition rates are sensitive to the time series properties of the input stimuli.