Stochastic, adaptive sampling of information by microvilli in fly photoreceptors.
Stochastic, adaptive sampling of information by microvilli in fly photoreceptors.
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DOI：
10.1016/j.cub.2012.05.047
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发表时间：
2012-08-07
期刊：
影响因子：
9.2
通讯作者：
Juusola, Mikko
中科院分区：
文献类型：
--
作者：
Song, Zhuoyi;Postma, Marten;Billings, Stephen A.;Coca, Daniel;Hardie, Roger C.;Juusola, Mikko
在苍蝇的感光器中，光被聚焦到由数万个微绒毛组成的光敏波导（即横纹肌）上。每个微绒毛都能够产生基本的反应，量子凸点，以响应单光子使用随机操作的光转导级联。虽然我们对级联反应了解很多，但对微绒毛群体的协同作用如何将光变化编码为神经信息以及苍蝇和其他昆虫的光感受器的超微结构和生物化学机制如何进化与它们执行的信息采样和处理有关知之甚少。我们生成了生物病理学上真实的苍蝇感光器模型，它准确地模拟了视觉信息的编码。通过比较随机模拟与果蝇光感受器的单细胞记录，我们展示了30，000个微绒毛的自适应采样如何捕获自然对比度变化的时间结构。在每次撞击之后，使单个微绒毛短暂地（约100-200 ms）不应，从而随着强度的增加而降低量子效率。不应期对抗饱和，动态和随机地调节微绒毛的可用性（凸块产生率：采样率），而细胞内钙和电压适应凸块幅度和波形（样本大小）。这些自适应采样原理导致对自然光变化的鲁棒编码，这既近似于感知对比度恒定性，又增强了不同光照条件下的新事件，并预测了具有不同视觉生态的一系列物种的信息处理。这些结果澄清了为什么苍蝇光感受器的结构和功能，因为他们这样做，连接感官信息的感官进化和揭示神经信息处理的随机性的好处。结果定义了苍蝇感光器中微绒毛群体如何编码信息微绒毛的可用性和响应波形将光变化映射为信息通过简单的自适应采样原理理解编码机制采样原理预测其他物种的感光器结构和编码
In fly photoreceptors, light is focused onto a photosensitive waveguide, the rhabdomere, consisting of tens of thousands of microvilli. Each microvillus is capable of generating elementary responses, quantum bumps, in response to single photons using a stochastically operating phototransduction cascade. Whereas much is known about the cascade reactions, less is known about how the concerted action of the microvilli population encodes light changes into neural information and how the ultrastructure and biochemical machinery of photoreceptors of flies and other insects evolved in relation to the information sampling and processing they perform. We generated biophysically realistic fly photoreceptor models, which accurately simulate the encoding of visual information. By comparing stochastic simulations with single cell recordings from Drosophila photoreceptors, we show how adaptive sampling by 30,000 microvilli captures the temporal structure of natural contrast changes. Following each bump, individual microvilli are rendered briefly (∼100–200 ms) refractory, thereby reducing quantum efficiency with increasing intensity. The refractory period opposes saturation, dynamically and stochastically adjusting availability of microvilli (bump production rate: sample rate), whereas intracellular calcium and voltage adapt bump amplitude and waveform (sample size). These adapting sampling principles result in robust encoding of natural light changes, which both approximates perceptual contrast constancy and enhances novel events under different light conditions, and predict information processing across a range of species with different visual ecologies. These results clarify why fly photoreceptors are structured the way they are and function as they do, linking sensory information to sensory evolution and revealing benefits of stochasticity for neural information processing. ► Results define how microvilli populations in fly photoreceptors encode information ► Availability and response waveforms of microvilli map light changes to information ► Encoding mechanisms understood through simple adaptive sampling principles ► Sampling principles predict photoreceptor structure and encoding in other species
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DOI：
10.1016/j.cub.2009.12.006
发表时间：
2010-02-09
期刊：
Current biology : CB
影响因子：
--
作者：
Fain GL;Hardie R;Laughlin SB
通讯作者：
Laughlin SB
果蝇光感受器的光适应性：ii。温度上升会增加可靠信号传导的带宽。
影响因子：
3.8
作者：
Juusola, M;Hardie, RC
通讯作者：
Hardie, RC
影响因子：
16.2
作者：
Kiselev, A;Socolich, M;Ranganathan, R
通讯作者：
Ranganathan, R
影响因子：
16.2
作者：
HARDIE, RC;MINKE, B
通讯作者：
MINKE, B
影响因子：
64.8
作者：
Niven, JE;Vähäsöyrinki, M;Weckström, M
通讯作者：
Weckström, M