C. elegans stores temperature experiences and can induce temperature acclimation linked with cold tolerance (Ohta et al., Nature commun, 2014; Okahata et al., Science Advances, 2019). Here we found that a neural circuit containing ASJ sensoryneuron, PVQ and RMG interneurons, a head-to-tail neural circuit, is a central circuit in temperature acclimation. CREB/CRH-1 functions to regulate temperature acclimation in the ASJ thermosensory neuron and RMG head interneuron. Presynaptic signal enhancement by PKCgf revealed PVQ tail interneuron function as a bridge between the ASJ and RMG via glutamatergic signaling. Ca2+ imaging demonstrated that activities in ASJ, PVQ and RMG fluctuated with temperature changes, suggesting that these neurons are involved in temperature signaling. To identify the upstream sensoryneuron activating PVQ, we monitored PVQ neural activity of mutants defective in thermo-sensitivity of ASJ, ADL and ASG thermosensory neurons. We found that the Ca2+ levels of PVQ in
tax-4(CNG channel) mutant defect in thermo-sensation of ASJ were higher than those in wild-type. Conversely, changes in Ca2+ levels of PVQ were decreased in
deg-1 mutant impairing DEG/ENaC thermoreceptor of ASG thermosensory neuron. These results suggest that PVQ interneuron integrates temperature signaling from two upstream sensory neurons, ASG and ASJ. We hypothesized that ASG positively regulates the PVQ via the ASK sensory neuron, because this is the shortest pathway from ASG to PVQ. To examine whether ASK bridges between ASG and PVQ, we used reconstituted-caspase that can occur selective ablation of targeted cells. We found that the Ca2+ levels of PVQ in both ASG-ablated animals and ASK-ablated animals were decreased, suggesting that ASK bridges neural signaling between ASG and PVQ. Altogether, the ASJ and ASG which transmits an opposite temperature signaling to the tail interneuron PVQ. PVQ in turn releases glutamate to the RMG interneuron located in the head. We propose this body-wide circuit as the modulatory mechanism of temperature acclimation.