Descending facilitation: From basic science to the treatment of chronic pain

It is documented that sensory transmission, including pain, is subject to endogenous inhibitory and facilitatory modulation at the dorsal horn of the spinal cord. Descending facilitation has received a lot of attention, due to its potentially important roles in chronic pain. Recent investigation using neurobiological approaches has further revealed the link between cortical potentiation and descending facilitation. Cortical-spinal top-down facilitation, including those relayed through brainstem neurons, provides powerful control for pain transmission at the level of the spinal cord. It also provides the neuronal basis to link emotional disorders such as anxiety, depression, and loss of hope to somatosensory pain and sufferings. In this review, I will review a brief history of the discovery of brainstem-spinal descending facilitation and explore new information and hypothesis for descending facilitation in chronic pain.