The cat lumbar spinal cord somatotopic map is unchanged after peripheral nerve crush and regeneration.

Microelectrode recordings have been made of the activity of neurons in the left dorsal horn of the lumbar enlargement of cats in which the left sciatic and saphenous nerves had been crushed 9 months earlier. In normal animals the receptive fields of neurons in this part of the spinal cord excited by gentle mechanical stimulation of the leg are somatotopically organized in such a way that they provide a map of the hind-leg skin. Previous experiments have shown that 9 months after cutting the nerves supplying the lower half of the hind-leg this somatotopic map is lost. The present experiments show that 9 months after nerve crush the somatotopic map is restored and indistinguishable from that seen in normal animals.