Damage to the insula disrupts addiction to cigarette smoking

Nasir Naqvi was a graduate student at the University of Iowa Carver College of Medicine in the Division of Cognitive Neuroscience, working with Antoine Bechara and Hanna Damasio on the Iowa Patient Registry. By 2007 Bechara, Hanna Damasio, and David Rudrauf had moved with Antonio Damasio to the University of Southern California's Brain and Creativity Institute (2005); the paper is a cross- institutional collaboration drawing on the Iowa lesion-patient registry — which Hanna Damasio had built across two decades of careful records and neuroimaging — and the cognitive-neuroscience programme at USC.

Published in Science on 26 January 2007, this is a primary lesion-method report. The cohort: 19 smokers with focal brain damage involving the insula, matched against 50 smokers with brain damage not involving the insula. The 19 insula-lesion patients had quit smoking with a degree of ease — without relapse, without persistent craving — that the comparison group had not; twelve quit immediately upon their stroke or aneurysm. Science is the highest-impact venue, and a lesion- method paper landing there carries unusual evidential weight: the causal inference (the insula is necessary for sustaining nicotine addiction, not merely correlated with it) is what fMRI co-activation studies cannot produce.

The piece sits as a primary report and as the canonical causal- evidence citation for the insula's role in addiction and, by extension, in interoception as a felt state. The argument that ties it to Craig's interoception frame is that the felt urge to smoke is an interoceptive sensation — the body's craving represented in the insula as a feeling — and the loss of the urge after insula damage is direct evidence that the insula is the substrate of the feeling itself. The lineage runs straight from Damasio's 1994 somatic-marker hypothesis through this paper: same Iowa registry, same lesion-method tradition, extended from prefrontal-cortex decision-making into anterior-insula interoception. The post-2007 addiction-medicine literature on craving and insula cites it nearly universally.

The stake is scientific and methodological. The lesion-method tradition at Iowa was built on the registry's patient data, painstakingly collected by the Damasios over twenty years; this paper is one of the high-water marks of that programme. Naqvi later moved to Columbia and has continued working on insula-and-addiction; Bechara remained at USC. None of the authors had a commercial position to defend, but the paper's clinical implications — that the insula is a target for addiction intervention — have driven a substantial subsequent literature on transcranial-stimulation approaches to nicotine cessation, in which the authors have some standing as the field's originators. Read the paper for what it cleanly demonstrates; read the post-2007 stimulation work for what it cautiously implies.