Neural substrates of pain and analgesia

The anatomic, physiologic, and chemical properties of systems involved in encoding and transmitting nociceptive input provide a basis for understanding the experience of pain. Moreover, the fact that these nociceptive systems can be modulated by other neural and humoral systems provides explanations for pain inhibition, pain enhancement, and the variability observed with various types of pain. Neural plasticity and permanent restructuring of these systems following injury also are likely to contribute to short- and long-term changes in the experience of pain. In summary, our understanding of acute and chronic pain has been significantly advanced through investigations of the neural substrates of pain and analgesia.