Network architecture of neural signaling in C. elegans

While the architecture of the C. elegans connectome has been extensively characterized, much less is known about the organization of causal signaling networks arising from functional interactions between neurons. Understanding how the effective communication pathways diverge from the underlying structure is a central question in neuroscience. We analyze the modular architecture of the C. elegans signal propagation network and compare it to the underlying anatomical wiring. We identify a hierarchy of communities where the coarsest tier contains 6 modules. We find that signaling modules are not aligned with the modular boundaries of the anatomical network, highlighting an instance where function deviates from structure. We analyze the cellular compositions of this signaling architecture and find that its modules are enriched for specific cell types and functions, indicating their neurobiological relevance. Lastly, we identify a "rich club" of hub neurons in the signaling network where membership differs from rich clubs detected in the anatomy. Our results provide new insight into the interplay between brain structure, the connectome, and brain function, in the form of a system-wide causal signal propagation atlas.