C. elegans wired and wireless connectome: insights into principles of nervous system structure and function

Caenorhabditis elegans is one of the primary model organisms for neuroscience research due to its well annotated and compact nervous system. Being the first organism with a mapped connectome, published nearly 40 years ago, it holds a critical place in the field of neuroscience. Over the past decades, exhaustive mapping of the C. elegans nervous system at the molecular and cellular level, along with the development of tools to probe neural dynamics, have given invaluable insights on neuronal communication at the cellular, circuit, and systems level. In this review, we discuss key features of the C. elegans connectome, the wired (synaptic) as well as the wireless (extrasynaptic) network, and their role in executing complex behaviours. We delve into recent advances in C. elegans neuroscience, highlighting how in vivo and in silico studies have elucidated functional principles that govern sensory integration and the importance of assessing behavioural features at a systems level. With emerging connectomes of other, more complex organisms, this field offers a robust framework for testable hypotheses and comparative connectomics.