Temperature sensing and context-dependent thermal behavior in nematodes

As small ectotherms, whose temperature equilibrates almost instantly with that of their environment, free-living nematodes rely on their behavior for thermoregulation. Caenorhabditis elegans has been extensively used as a model to address the fundamental mechanisms involved in thermosensation and the production of temperature-dependent behaviors. Behavioral responses include avoidance of acute noxious heat or cold stimuli and thermotactic responses to innocuous temperatures to produce oriented navigation in spatial thermogradients. In order to produce these behaviors, C. elegans relies on its ability to detect thermal cues with exquisite sensitivity, orchestrate a set of specific behavioral responses and adapt these responses in specific contexts, including according to past sensory experience and current internal states. The present review focuses on recent advances in our understanding of the processes occurring at the molecular, cellular, and circuit levels that enable thermosensory information processing and plasticity. • Kainate-type glutamate receptors and degenerin are new molecular thermoreceptors. • The list of Caenorhabditis elegans thermo-responsive sensory neurons is continuously expanding. • Thermal changes and absolute temperature are encoded by distinct thermosensory neurons. • Thermal information processing in the thermosensory circuit is strongly context-dependent. • Intra- and extracellular molecular pathways control thermo-nociceptive plasticity.