Sentience, Pain, and Anesthesia in Advanced Invertebrates

Book excerpt: There is an emerging view, supported by animal welfare legislation in a number of countries, that some advanced invertebrates are self-aware, sentient beings with the ability to feel pain. Sentience must encompass elements of time and neural complexity, including memory and learning, which leads us to ask: At what convergent point in the evolution of nervous systems does the subjective sensation of pain arise? Here we start to grapple with this issue, particularly with regard to arthropods and cephalopod molluscs, and to consider the most appropriate ways of anesthetizing them to minimize pain wherever possible. We also report on the development of cell culture techniques to understand the actions of the anesthetics being used. A better understanding of sentient creatures, other than ourselves, may eventually assist future development of artificial intelligence, particularly if we are able to perceive whatever common neural features underlie sentience in those animals that possess it.