The body's heat regulation circuit involves neurons in the skin sensing heat, relaying signals to the spinal cord's dorsal horn, then to the lateral parabrachial area, and finally to the preoptic area (POA) in the hypothalamus, which signals the brain and body to heat up or cool down.

“You have this shell, which is basically skin. And within the skin, you have neurons, nerve cells. Those nerve cells have channels or receptors on them. They're called trip channels. There are some other ones as well, which basically sense changes in heat. So, if I were to put a hot object on your hand or your arm, or for instance, if I were to put a hot object on your hand or arm and then remove that hot object, those neurons would respond to that. They would send electrical signals into your spinal cord. And that's where the next station of the circuit resides. In your spinal cord, you've got a little cluster of neurons that exists at the top part of your spinal cord called the dorsal horn. The name again doesn't matter. And those neurons specifically relay heat information up to another area of your brain. Now, here's where we get into some fancy names. It's the lateral parabrachial area. You don't need to know lateral parrachial area, but it's a relay station. The lateral parabra area sends electrical signals to the POA. And I would like you to know POA. The POA stands for preoptic area.”