ABSTRACT
Investigation of the dorsal column visceral pain pathway was extended to monkeys to ensure that evidence like that obtained in rats could be obtained in a species whose nervous system closely resembles that of humans. Long ascending axons in the dorsal column of the mammalian spinal cord are generally thought to arise either from dorsal root ganglion cells or from neurons whose cell bodies are located in the gray matter of the dorsal horn. In order to determine the brain structures that are affected by colorectal distention and the changes that might occur following a lesion of the dorsal column, a functional magnetic resonance imaging study was initiated. Clinical evidence indicates that the human dorsal column contains an important visceral pain pathway that, when interrupted, can relieve the pain of cancer affecting pelvic viscera. The dorsal column also mediates responses to weak mechanical stimulation of the skin.
