An experimental sub-human primate model of central pain has been developed, which corresponds with major features of human intractable pains. Macaques have been observed to predictably mutilate their distal appendages after neuropathological or neurosurgical lesions at spinal or brain levels; these are lesions which are known to produce chronic abnormal pains in humans, e.g., spinal syringomyelia, cerebral vascular accidents, posterior rhizotomies, anterolateral cordotomy, and mesenchephalic spinothalamic tractotomy. The evidence strongly indicates that these abnormal spontaneous sensations: (a) result from extensive interruption of the spinothalamic system at various levels; (b) are independent of peripheral input from the affected dermatomes; (c) are independent of transmission via long ascending spinal tracts; (d) are independent of supraspinal descending control mechanisms; (e) are relatively independent of segmental spinal mechanisms; or (f) visceral afferents. They appear to be generated at a brain level.