Damasio, Antonio and Damasio, Hanna (2016) Pain and other feelings in humans and animals. Animal Sentience 3(33)
Brian Key, Why fish do not feel pain
Evidence from neuroanatomy, neurophysiology, and neuropsychology suggests that the experience of feelings in humans does not depend exclusively on structures of the cerebral cortex. It does not seem warranted to deny the possibility of feeling in animals on the grounds that their cerebral cortices are not comparable to those of humans.