491: Stable insular spectral organisation underlies frequency-specific encoding of chronic pain states

Topic: Clinical Science
Subtopic: Pain category (ICD-11), Chronic neuropathic pain, Developing methodology/technology, Non-pharmacological treatments, Electrophysiology

Background and Aims: Chronic neuropathic pain persists over years yet fluctuates markedly from day to day. How stable neural abnormalities give rise to these dynamic pain states remains unclear. The insular cortex plays a central role in integrating sensory and affective dimensions of pain, but its spectral organization during ongoing chronic pain has not been well characterized. We aimed to dissociate stable disease-related neural patterns from day-to-day symptom fluctuations in the human insula.

Methods: We analyzed multi-day bilateral intracranial EEG recordings from the insular cortex of six individuals with chronic neuropathic pain, spanning 34 recording days and more than 22 hours of artifact-free data. Resting-state recordings were obtained under standardized conditions. Spectral power and intra-insular functional connectivity were quantified using bipolar signals and linear mixed-effects models with explicit control for longitudinal temporal drift. Daily assessments of pain intensity and unpleasantness were modeled as within-subject predictors of neural activity

Results: The insula exhibited a stable baseline spectral organization characterized by an anterior-to-posterior gradient with posterior fast-band suppression and relative spectral slowing. This pattern was reproducible across days and independent of pain fluctuations. Superimposed on this stable organization, day-to-day pain variation was associated with frequency-specific changes in the posterior insula. Pain intensity was most strongly associated with increased contralateral posterior alpha power (partial R² ≈ 0.33), whereas pain unpleasantness was preferentially associated with increased contralateral posterior beta power (partial R² ≈ 0.19). In contrast, intra-insular functional connectivity showed comparatively modest variation across pain states.

Conclusions: Stable cortical spectral organization supports dynamic encoding of distinct chronic pain states within the same brain region. Posterior insular alpha and beta oscillations provide dissociable signatures of pain intensity and unpleasantness, respectively, offering physiologically grounded sensing signals for adaptive, closed-loop neuromodulation therapies.

References: n/a

Presenting Author: Chang-Chia Liu
Submitting Author: CHANG-CHIA LIU

Senior Author: Chang-Chia Liu

IASP 2026 Global Year theme of Neuropathic Pain: Yes

• Mark Quigg: MD - University of Virginia School of Medicine
• Patrick Finan: PhD - University of Virginia School of Medicine
• W. Jeff Elias: MD - University of Virginia School of Medicine