A central problem of neuroscience involves uncovering the principles governing URLanization of nervous systems which ensure robustness in brain development. The nematode Caenorhabditis elegans , where genetically identical individuals possess the same complement of neurons located at invariant positions, provides us with a URLanism for studying this question. In this paper, we focus on the  connection structure and spatial arrangement of the neurons comprising the somatic neuronal network of URLanism to understand the key developmental constraints underlying the designof a simple nervous system . We observe that lineage distance between neurons , rather than the physical distance between their cell bodies, strongly influences the probability of a connection between them. In addition, the length of neuronal processes, as well as, their birth times determine connectivity. Together, these results help connect the physical location and morphology of neurons with the URLanization of the network. Further, neurons coordinating activity across distinct neuronal clusters are seen to appear early which relates the temporal hierarchy imposed by development to the functional role of neurons. By providing a framework for a mechanistic understanding of how developmentshapes a nervous system, our results complement interpretive analysis of how efficiency and optimality govern its design . Providing crucial insights for understanding principles that may be common across URLanisms, our study shows how the trajectory in the developmental landscape constrains the eventual spatial and network URLanization of a nervous system.
A central problem of neuroscience involves uncovering the principles governing URLanization of nervous systems which ensure robustness in brain development. The nematode Caenorhabditis elegans provides us with a URLanism for studying this question. In this paper, we focus on the invariant connection structure and spatial arrangement of the neurons comprising the somatic neuronal network of URLanism to understand the key developmental constraints underlying its design . We observe that neurons with certain shared characteristics - such as, neural process lengths, birth time cohort, lineage and bilateral symmetry - exhibit a preference for connecting to each other. Recognizing the existence of such homophily helps in connecting the physical location and morphology of neurons with the URLanization of the network. Further, the functional identities of neurons appear to dictate the temporal hierarchy of their appearance during the course of development . Providing crucial insights into principles that may be common across URLanisms, our study shows how the trajectory in the developmental landscape constrains the eventual spatial and network URLanization of a nervous system.
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, where genetically identical individuals possess the same complement of neurons located at invariant positions,
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the designof a simple nervous system
its design
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lineage distance between neurons , rather than the physical distance between their cell bodies, strongly influences the probability of a connection between them. In addition, the length of neuronal processes, as well as, their birth times determine connectivity. Together, these results help connect
neurons with certain shared characteristics - such as, neural process lengths, birth time cohort, lineage and bilateral symmetry - exhibit a preference for connecting to each other. Recognizing the existence of such homophily helps in connecting
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neurons coordinating activity across distinct neuronal clusters are seen to appear early which relates
the functional identities of neurons appear to dictate
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imposed by development to the functional role of neurons. By providing a framework for a mechanistic understanding of how developmentshapes a nervous system, our results complement interpretive analysis of how efficiency and optimality govern its design
of their appearance during the course of development
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