# Developmental trajectory of Caenorhabditis elegans nervous system governs its structural organization

## TL;DR

This study investigates how the developmental processes and characteristics of neurons in C. elegans influence the organization and structure of its nervous system, revealing principles that may be common across species.

## Contribution

It uncovers developmental constraints and homophily principles that shape the neural network's structure and organization in C. elegans.

## Key findings

- Neurons with shared traits tend to connect more frequently.
- Neuron location and morphology relate to network topology.
- Neuron birth timing influences functional identity and development.

## Abstract

A central problem of neuroscience involves uncovering the principles governing the organization of nervous systems which ensure robustness in brain development. The nematode Caenorhabditis elegans provides us with a model organism 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 this organism 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 topological organization 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 many organisms, our study shows how the trajectory in the developmental landscape constrains the eventual spatial and network topological organization of a nervous system.