|MadSci Network: Neuroscience|
There are a couple of reasons that I can think of that would make your hand feel hot when it is cold. First a little background. Your skin has two types of temperature receptors. Receptors are parts of nerve cells that send signals to let the brain and spinal cord know what is happening. The cold receptors tell your spinal cord that the skin is cold and the warm ones the skin is warm. When the skin temperature gets really cold, the cold receptors send their signals back to the spinal cord (which in turn informs the brain). However, the warm receptors might start sending their signals back when it gets REAL cold too. This might make it feel like the skin is warm or even hot. In addition, there are also pain receptors. If these receptors are also activiated, this might trick the spinal cord into thinking that it is hot rather than cold. In addition, when your skin is cold, if something that is cold, but warmer than your skin, comes in contact with your skin, it will feel warm because it is warmer than your skin. For example, it your skin is 40 degrees F, and something that is 50 degrees F comes in contact with your skin, even though the 50 degree thing is cold, it is warmer than the skin and would feel warm. SO when your skin is cold, if something warmer contact with your skin, it might make your skin feel warm.
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