Stepping inside a perfectly air-conditioned room during the summer sends a pleasant tingle across your skin. It’s refreshing, and a sensation whose mechanisms are now becoming less of a mystery.

A new study in mice from researchers at the University of Michigan is shedding light on how your skin knows the temperature is cool outside — and why your brain cares. The team successfully “traced” the entire pathway that handles cool temperatures, from skin to brain, making it the first time scientists have fully mapped a temperature-sensing neural circuit. Notably, cooler temperatures have their own dedicated neural pathway, meaning your body doesn’t just lump “not-hot” into one category. Rather, it evolved separate routes to detect hot and cold.

Here’s how it works: When the skin feels something in the 59 to 77°F range, tiny molecular “thermometers” get triggered. These activate primary sensory neurons, which ping the spinal cord. There, a previously unknown player steps in: an amplifier neuron, whose job it is to prevent the signal from getting lost in the noise. Then, the signal zooms up to the brain, giving you that delicious “ahh” moment when a cool breeze brushes by on a hot day.

Why does this matter? Well, more than 70% of people on chemo report cold-induced pain, which can happen soon after an infusion. Because the pathway studied here is not involved in that particular type of pain, understanding it better could help scientists figure out which kind is, and how to fix it — without affecting your ability to enjoy the crisp AC during a grocery store run. And, because we must say it: That sounds pretty cool.