How do you feel — now? The anterior insula and human awareness

The 2009 follow-up to Craig's 2002 review extends the interoception argument into the territory of consciousness. The earlier paper named the right anterior insula as the cortical re-representation of homeostatic afferent state; the 2009 paper makes the stronger claim that the anterior insula — and specifically the von Economo neurons it contains, a large bipolar projection cell type concentrated in humans, great apes, elephants, and cetaceans (with later-reported homologues in a handful of other large-brained mammals) — is the substrate for the moment-to-moment sense of being a feeling self.

Nature Reviews Neuroscience again, again as synthesising review rather than primary report. Craig was at Barrow Neurological Institute throughout. The piece integrates a wider body of work than the 2002 paper — fMRI emotion studies, lesion work on patients with anterior insula damage, the von Economo neuron literature from John Allman and colleagues at Caltech, comparative neuroanatomy across primates — and proposes that the anterior insula constructs awareness in roughly 125-millisecond intervals, each pulling current interoceptive state into a unified felt moment of being.

The piece sits as the canonical citation for the anterior-insula-as-substrate-of-awareness hypothesis. The hypothesis itself is contested — Anil Seth's predictive-processing work places the substrate of subjective experience across a wider cortical network, and Lisa Feldman Barrett's constructed-emotion account reads the same anatomy as a multimodal integrative hub rather than a feeling-self locus. But Craig's 2009 framing is the position those subsequent accounts are arguing against, and any serious engagement with the insula-and-consciousness literature runs through this paper.

The stake is again Craig's career-long programme, and by 2009 the ambition has grown. The 2002 paper named a sensory modality; the 2009 paper claims a substrate of consciousness. The move is larger, the evidence base is thinner relative to that move, and the citation life of the piece is correspondingly enormous and slightly outsized relative to what the data support. Read it as the bold-claim statement of a position, not as a settled finding.