The Case of Octopus vulgaris: exploring neural hallmarks for consciousness

Is there sufficient evidence to make a strong case for a form of sensory consciousness in cephalopod molluscs? Over the past two decades, such a case has been made on a number of occasions by researchers across a variety of disciplines. Here we will survey evidence drawn from current developmental, anatomical, physiological, and behavioral studies and attempt to build the most systematic and substantive case yet for cephalopod consciousness.

Recent discoveries suggest that cephalopod nervous system includes some of the same genetic innovations that characterized the rise of complex brains in the vertebrates (e.g., expansion of the protocadherin gene family, large number of orphan genes, existence of active retrotransposons). These and other genomic and morphological novelties, as well as recent revelations regarding cognitive abilities in cephalopods – mirroring those of higher vertebrates – further bolster the argument we make here: namely that cephalopod molluscs are fully capable of conscious experience, albeit a variety that is markedly different from the sort of subjectivity experienced by humans and other vertebrates.

We will also review recent technical improvements in the analysis of neural correlates of brain activity in the octopus, and will present our recent findings in assessing spontaneous brain activity in O. vulgaris in the search of the neural hallmarks of consciousness in these animals.