A. D. (Bud) Craig

Neuroanatomist (Barrow Neurological Institute) whose account of interoception and the insula is the reference framework the modern field is built on — and that Seth both extends and departs from. See his two foundational papers craig-2002-interoception and craig-2009-anterior-insula.

The anatomy: interoception as the afferent side of homeostasis

Craig’s core contribution is the lamina-i-spinothalamocortical-pathway: small-diameter (Aδ/C) afferents from all tissues → lamina I of the dorsal horn → the dedicated thalamic relay VMpo → the dorsal posterior insula. This is the “long-missing afferent complement of the efferent autonomic nervous system” — the sensory limb of homeostasis. Its consequence is a reclassification of pain, temperature, itch, and sensual touch as interoceptive (feelings from the body) rather than aspects of exteroceptive touch.

The insular hierarchy and the emotion dyad

A posterior→mid→anterior gradient: primary objective interoceptive maps (posterior) → integration (mid) → subjective re-representation (“how you feel”) in the anterior insula (AIC), right-lateralized in humans. Craig pairs the insula (limbic sensory cortex, feeling) with the ACC (limbic motor cortex, motivation/agency): together they constitute an emotion. See insular-cortex.

Awareness (Craig 2009)

Craig extends the hierarchy to consciousness: the AIC is proposed to “engender human awareness” via the global-emotional-moment model, with von-economo-neurons as the substrate and the salience-network as the functional home. He grounds James’s and Damasio’s (somatic-marker-hypothesis) intuitions in specific anatomy, and thus in embodied-selfhood (“the material me”).

Point of divergence from Seth

Craig’s architecture is an ascending re-representation hierarchy with a comparator at the top (AIC) — feelings are read out from integrated afferent signals. Seth adopts the same anatomy but recasts its computation as top-down predictive inference (predictions descend, prediction errors ascend). Notably Craig 2009 already gestures at prediction (the AIC represents “predictions of future feelings”; anxiety as “distorted interoceptive predictions”), so the divergence is about architecture (ascending-integration vs descending-generative), not whether prediction exists at all. See feedforward-vs-predictive-interoception.