Insular Cortex Encodes Sickness

Researchers injected mice with prostaglandin E2, an immune‑system signal, and recorded neural activity showing the insular cortex's ensemble patterns tracked 'sickness' behaviours better than primary somatosensory areas. The result suggests the insula integrates bodily inflammatory signals into a unified subjective state of being unwell. — If the insula is a hub that constructs a global 'I am sick' state, that reframes chronic‑illness mechanisms, placebo/nocebo effects, and potential neural targets for treating persistent malaise.