Pain and the PAG: Learning from painful mistakes

摘要

Pain is evolutionarily old and shared among many species. None of us escapes experiencing this most fundamental of sensory and emotional percepts, which is clearly beneficial as our built-in alarm system, warning us of direct or impending injury. Oddly, we often only think of pain as the perceptual consequence of such injury and rarely do we make the link that the purpose of pain is to motivate decisions leading to action and behavioral change (for example, guarding an injured limb while tissue heals) and, moreover, to teach us what caused the pain in the first place so it can be avoided in future (for example, not touching a pan on a hot stove). In thfchealthy state, pain can therefore be considerel a teaching signal that allows us to learn what kind of actions should be avoided for our own benefit, and it is this kind of learning process that an exciting study published in this issue of Nature Neuroscience investigates1. Here, Roy and colleagues highlight the relevance of the brainstem's periaqueductal gray matter as a region that is important for learning how to avoid pain.