Hierarchical Channel System Drives Stimulus Specificity and Polymodal Encoding in A Mechano-Cold Sensory Neuron

Polymodal sensory neurons integrate diverse stimuli for environmental perception, but their modality discrimination mechanisms remain unclear. We focused on Caenorhabditis elegans inner labial type 1 (IL1) neurons, key polymodal neurons mediating mechanical and cold responses, and identified a hierarchical channel system supporting their multimodal function. Specifically, DEG-1 sodium channels are dedicated mechanotransduction receptors; GLR-3 glutamate receptors are the main rapid cold sensors, driving cold-induced calcium signals and behaviors; TRPA-1 bidirectionally modulates mechanical adaptation via calcium signaling and promotes cold-related longevity. This framework reveals a polymodal design logic: dedicated channels (DEG-1/GLR-3) process discrete modalities in parallel for specificity, while TRPA-1 regulates both. Our work provides a molecular blueprint for IL1's precise stimulus processing, offering insights into conserved multimodal integration mechanisms across lineages.