Bilateral Neuron Pairs Share Redundant Network Roles Despite Incomplete Connection Symmetry in Caenorhabditis elegans

Area of Science:

• Neuroscience
• Systems Biology
• Computational Biology

Background:

• The nervous system of C. elegans displays bilateral organization.
• Neuron pairs on the left and right sides have distinct connections.
• The functional convergence of these asymmetric pairs is not fully understood.

Purpose of the Study:

• To investigate bilateral redundancy in the C. elegans nervous system.
• To determine how neuron pairs with asymmetric connections achieve similar network roles.
• To analyze the C. elegans connectomes in both hermaphrodites and males.

Main Methods:

• Analysis of adult hermaphrodite and male C. elegans connectomes.
• Application of three graph-theoretic measures: connectivity similarity, motif-fingerprint difference, and path compensation.
• Comparison with null models to distinguish redundancy from simple bilateral symmetry.

Main Results:

• Bilateral neuron pairs demonstrated higher redundancy than other neuron pairs across all measures.
• Null-model comparisons indicated that bilateral asymmetry, not just symmetry, contributes to redundancy.
• Redundancy patterns varied, being more pronounced in hermaphrodite interneurons compared to sensory neurons.

Conclusions:

• Bilateral redundancy is a systematic principle in the C. elegans connectome.
• This redundancy is actively generated by neural asymmetry, not merely a consequence of symmetry.
• Understanding this principle offers insights into nervous system organization and function.