The substantia gelatinosa of Rolando.
D000818:Animals; D002415:Cats; D000882:Haplorhini; D009410:Nerve Degeneration; D009411:Nerve Endings / Q000033:anatomy & histology; D013116:Spinal Cord / Q000033:anatomy & histology*; D013127:Spinal Nerves / Q000601:surgery