Abnormal physiology of the dorsal horn as related to the deafferentation syndrome.

The spinal cord dorsal horn has been implicated in the generation of pain and dysesthesias following nerve and nerve root damage and/or avulsion, as well as following damage in adjacent spinal cord regions. Alterations in the functional properties of dorsal horn neurons occur after deafferentation and may underlie the occurrence of abnormal sensations referred to the denervated body part. Abnormal activity following deafferentation has also been noted at thalamic and cortical levels. Some of these post-denervation functional changes, determined anatomically and/or electrophysiologically, are reviewed as well as the results of behavioral studies of the deafferentation syndrome in the rat.