Zaslaver Alon, Liani Idan, Shtangel Oshrat, Ginzburg Shira, Yee Lisa, Sternberg Paul W
Genetics Department, Silberman Life Science Institute, The Hebrew University of Jerusalem, Jerusalem 91904, Israel; and
Genetics Department, Silberman Life Science Institute, The Hebrew University of Jerusalem, Jerusalem 91904, Israel; and.
Proc Natl Acad Sci U S A. 2015 Jan 27;112(4):1185-9. doi: 10.1073/pnas.1423656112. Epub 2015 Jan 12.
Animals with compact sensory systems face an encoding problem where a small number of sensory neurons are required to encode information about its surrounding complex environment. Using Caenorhabditis elegans worms as a model, we ask how chemical stimuli are encoded by a small and highly connected sensory system. We first generated a comprehensive library of transgenic worms where each animal expresses a genetically encoded calcium indicator in individual sensory neurons. This library includes the vast majority of the sensory system in C. elegans. Imaging from individual sensory neurons while subjecting the worms to various stimuli allowed us to compile a comprehensive functional map of the sensory system at single neuron resolution. The functional map reveals that despite the dense wiring, chemosensory neurons represent the environment using sparse codes. Moreover, although anatomically closely connected, chemo- and mechano-sensory neurons are functionally segregated. In addition, the code is hierarchical, where few neurons participate in encoding multiple cues, whereas other sensory neurons are stimulus specific. This encoding strategy may have evolved to mitigate the constraints of a compact sensory system.
具有紧凑感觉系统的动物面临着一个编码问题，即需要少量的感觉神经元来编码其周围复杂环境的信息。以秀丽隐杆线虫为模型，我们探究化学刺激是如何由一个小型且高度连接的感觉系统进行编码的。我们首先构建了一个转基因线虫的综合文库，其中每只动物在单个感觉神经元中表达一种基因编码的钙指示剂。该文库涵盖了秀丽隐杆线虫感觉系统的绝大部分。在对线虫施加各种刺激的同时对单个感觉神经元进行成像，使我们能够以单个神经元分辨率编制出感觉系统的综合功能图谱。该功能图谱显示，尽管神经连接密集，但化学感觉神经元使用稀疏编码来表征环境。此外，尽管化学感觉神经元和机械感觉神经元在解剖学上紧密相连，但在功能上是分隔的。另外，编码是分层的，少数神经元参与编码多种线索，而其他感觉神经元则对特定刺激有反应。这种编码策略可能是为了缓解紧凑感觉系统的限制而进化出来的。
