A. D. (Bud) Craig

American functional neuroanatomist (Arthur Dewitt "Bud" Craig, Jr., 1951–2023). Directed the Atkinson Pain Research Laboratory at the Barrow Neurological Institute in Phoenix from 1986 until his retirement; died in July 2023 after a brief illness. His career- long programme was tract-tracing of the spinothalamic pathway in primates, particularly the lamina-I projection neurons that carry pain, temperature, and homeostatic-afferent signals. The most-cited single figure in the modern interoception literature: the term in its current sense is his reframing of Sherrington's old word, and the right-anterior-insula-as-substrate-of-feeling hypothesis is his.

Stake§

Craig's stake was scientific and intellectual, with the long-arc commitment of a neuroanatomist who spent thirty years on one problem. He was advancing a model he had built across his entire career; the 2002 and 2009 Nature Reviews Neuroscience reviews are the synthesis statements that secured his standing as the founder of the modern interoception field. His 2014 trade book How Do You Feel? An Interoceptive Moment with Your Neurobiological Self (Princeton University Press) extended the claims into popular consciousness. The strong version of his anterior-insula- as-consciousness claim has been criticised by Barrett, Seth, and others; Craig held to it.

Craig's foundational contribution was the proposition, articulated across his lamina-I tract-tracing primary work in the 1980s and 1990s and synthesised in How do you feel? Interoception (2002), that the body's homeostatic afferent signals — pain, temperature, itch, hunger, breath, visceral state — constitute a distinct sensory modality with its own thalamocortical pathway, not a special case of somatosensation. The pathway he traced runs through small-diameter spinothalamic fibres into the dorsal posterior insula and is re-represented in the right anterior insula as the substrate of conscious feeling. The lateralisation to the right hemisphere connected the construct to subjective emotional experience.

Craig's 2009 follow-up How do you feel — now? extended the argument into consciousness territory, placing the anterior insula and its von Economo neurons as the substrate for the moment-to-moment sense of being a feeling self. The strong version of this claim — that conscious awareness is constituted in roughly 125-millisecond intervals by the anterior insula — is what subsequent predictive-processing accounts (Seth, Barrett and Simmons, Stephan) have argued against. Craig's model is the position those accounts argue with; engagement with the modern insula-and-consciousness literature runs through his work.

Craig is the figure who, almost single- handedly, revived Sherrington's term and gave it modern anatomical specificity. The criticism that his strong claims — particularly about awareness and the von Economo neurons — outran the data is fair. The criticism that the field could have managed without his synthesis is not. The 2002 review is one of the most-cited papers in cognitive neuroscience; the 2009 follow-up shaped the consciousness debate for a decade and a half.