(45) Mapping Functional Connectivity Changes in Chronic Pain States Using Brain Stimulation Evoked Potentials

Introduction: Chronic pain is one of the most debilitating healthcare conditions, affecting more people annually than diabetes or hypertension. A major challenge in chronic pain management is understanding the complex interplay between brain networks that modulate pain perception. The brain processes pain signals through short- and long-range connections across different regions. Pathological disruptions in these networks, leading to hypo- or hyper-connectivity, contribute to the persistence of chronic pain. Traditional methods for mapping functional connectivity rely on correlative tools that lack temporal resolution and do not account for network interaction delays.

Methods: We analyzed clinical data from patients implanted with stereo-EEG electrodes to map functional connectivity changes across different pain states. Using single-pulse electrical stimulation, we recorded evoked cortical and subcortical responses (SPEP—Single Pulse Electrical Potentials) across multiple brain regions. To account for variable delays between recording channels, we used machine learning to dynamically model an evolving causal connectivity network.

Results: SPEP recordings revealed functional connectivity changes between high- and low-pain states across multiple patients. We quantified changes in network connectivity between brain regions of interest as a function of each patient's pain state by extracting dominant response waveforms to stimulation and measuring interactions across multiple brain sites. Our analysis reveals common network dynamics linked to pain states, offering insights into functional alterations underlying chronic pain.

Conclusion: This study highlights functional connectivity changes associated with high- and low-pain states in chronic pain patients. Understanding network dysfunctions offers insights into chronic pain mechanisms, informing stimulation targets and adaptive feedback strategies for deep brain stimulation to improve outpatient pain outcomes.