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Throughout the animal kingdom, there are numerous examples of neurons that respond to multiple stimuli and faithfully transmit information about those various inputs. In the mouse, for example, there are certain neurons that respond to both temperature and potentially damaging touch. In the fruit fly, there are neurons that sense light, temperature, pain, and proprioceptive stimuli—those arising as a result of body position and movement. And in C. elegans, two sensory neurons, known as PVD neurons, that run the length of the body on either side are thought to regulate proprioception as well as responses to harsh touch and cold temperature.
Scientists have now figured out how a single PVD neuron can relay two different stimuli: while harsh touch results in typical firing of the neuron—an impulse that travels the length of the cell—proprioception causes a localized response in one part of the cell with no ...