An update on the spinal and peripheral pathways of pain signalling

Abstract

Painful or potentially tissue-damaging stimuli are detected by primary sensory afferents that innervate the skin as well as internal tissues. The neurons that give rise to sensory afferents are located in the dorsal root ganglia (DRG) and transmit sensory information to the spinal cord where it is processed and further relayed to higher brain regions to ultimately generate the perception of pain. Both the DRGs as well as the spinal cord comprise a variety of morphologically, molecularly and functionally diverse neurons. The objective of this review is to provide an overview of the different types of sensory neurons and their proposed role in pain signalling. Moreover, I will discuss how pain related sensory information is processed in the dorsal horn of the spinal cord with an emphasis on recently delineated neural circuits that mediate pain hypersensitivity in the setting of nerve injury and inflammation.