2024 Volume 20 Issue 1 Pages 14-29
This study aimed to elucidate the relationship between changes in brain networks and emotional responses to additional pain-enhancing stimuli during the manifestation of cold-induced pain. We administered pain-inducing cold stimulus (6-7°C) to 15 healthy volunteers and evaluated their emotional responses using an 11-item scale, and scalp electroencephalography changes. From results of the emotion scale, factor analysis identified “arousal” and “emotional valence” as significant. Participants were categorized into groups with either high or low arousal, and high or low discomfort, based on these factors. We estimated the signal sources of the θ and low β bands, which showed changes in power values using the standardized low-resolution brain electromagnetic tomography method. Then, we calculated the composition of functional brain networks and their activity levels using constrained principal component analysis.
The present study revealed that during additional cold pain-enhancing stimuli, the main functional brain networks activated include the medial frontal cortex, associated with cognitive processes such as attention, contributing to increased arousal and discomfort levels. In contrast, decreased activity in the insular cortex contralateral to the stimulus, reflecting its regulatory role in cognitive processing of pain, helped suppress discomfort caused by cold pain.
