Emmons Scott W
Department of Genetics and Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, United States of America.
PLoS Biol. 2024 Dec 17;22(12):e3002939. doi: 10.1371/journal.pbio.3002939. eCollection 2024 Dec.
Despite decades of research on the Caenorhabditis elegans nervous system based on an anatomical description of synaptic connectivity, the circuits underlying behavior remain incompletely described and the functions of many neurons are still unknown. Updated and more complete chemical and gap junction connectomes of both adult sexes covering the entire animal including the muscle end organ have become available recently. Here, these are analyzed to gain insight into the overall structure of the connectivity network and to suggest functions of individual neuron classes. Modularity analysis divides the connectome graph into 10 communities that can be correlated with broad categories of behavior. A significant role of the body wall musculature end organ is emphasized as both a site of significant information convergence and as a source of sensory input in a feedback loop. Convergence of pathways for multisensory integration occurs throughout the network-most interneurons have similar indegrees and outdegrees and hence disperse information as much as they aggregate it. New insights include description of a set of high degree interneurons connected by many gap junctions running through the ventral cord that may represent a previously unrecognized locus of information processing. There is an apparent mechanosensory and proprioceptive field covering the entire body formed by connectivity of the many mechanosensory neurons of multiple types to 2 interneurons with output connections across the nervous system. Several additional significant, previously unrecognized circuits and pathways are uncovered, some involving unstudied neurons. The insights are valuable for guiding theoretical investigation of network properties as well as experimental studies of the functions of individual neurons, groups of neurons, and circuits.
尽管基于突触连接的解剖学描述，对秀丽隐杆线虫神经系统进行了数十年的研究，但行为背后的神经回路仍未得到完整描述，许多神经元的功能也仍然未知。最近，已获得更新且更完整的成年雌雄两性的化学连接组和缝隙连接组，涵盖了包括肌肉终末器官在内的整个动物体。在此，对这些连接组进行分析，以深入了解连接网络的整体结构，并推测各个神经元类别的功能。模块分析将连接组图划分为10个群落，这些群落可与广泛的行为类别相关联。强调了体壁肌肉组织终末器官的重要作用，它既是重要信息汇聚的场所，也是反馈回路中感觉输入的来源。多感觉整合的通路在整个网络中汇聚——大多数中间神经元具有相似的入度和出度，因此它们在聚集信息的同时也同样多地分散信息。新的见解包括对一组高度连接的中间神经元的描述，这些中间神经元通过贯穿腹神经索的许多缝隙连接相连，可能代表了一个以前未被认识到的信息处理位点。由多种类型的许多机械感觉神经元与2个中间神经元相连形成了一个覆盖整个身体的明显的机械感觉和本体感觉场，这2个中间神经元具有跨越神经系统的输出连接。还发现了几个其他重要的、以前未被认识到的神经回路和通路，其中一些涉及未研究过的神经元。这些见解对于指导网络特性的理论研究以及单个神经元、神经元群体和神经回路功能的实验研究具有重要价值。
