Dysregulated anterior insula reactivity as robust functional biomarker for chronic pain: convergent evidence from neuroimaging meta-analyses

Neurobiological pain models propose that the transition from acute to chronic pain is accompanied by neuropathological adaptations that mediate progressive pain processing dysfunctions. In contrast, meta-analytic studies on neurofunctional dysregulations in chronic pain have not revealed convergent evidence for robust alterations during experimental pain induction. Against this background, the present neuroimaging meta-analysis combined three different meta-analytic approaches with stringent study selection criteria for case-control functional magnetic resonance imaging experiments during acute pain processing with a focus on chronic pain disorders (i.e., fibromyalgia, irritable bowel syndrome, chronic low back pain, neuropathic pain; n = 295 patients, n = 211 controls; 86 foci). Across the meta-analytic approaches, convergent neurofunctional dysregulations in chronic pain patients were observed in the left anterior insula cortex, with study characteristics indicating generalized pain processing abnormalities. Seed-based resting-state functional connectivity based on a large publicly available dataset combined with a meta-analytic task-based approach identified the anterior insular region as a key node of an extended bilateral insula-fronto-cingular network, resembling the salience network. Moreover, the meta-analytic decoding showed that this region presents a high probability to be specifically activated during pain-related processes. Together, the present findings indicate that dysregulated left anterior insular activity represents a robust neurofunctional maladaptation and potential treatment target in chronic pain disorders.