Brain activity associated with pain perception has been revealed by numerous PET and fMRI studies over the past few decades. These findings helped to establish the concept of the pain matrix, which is the distributed brain networks that demonstrate pain-specific cortical activities. In this study, we applied four levels of pain stimuli to 22 subjects and measured brain activity, biological signals (continuous blood pressure, photo-plethysmogram, and electrocardiogram), and subjective evaluation in an fMRI environment. We then calculated the peripheral arterial stiffness βart of the fingertip from the measured biological signals, which is an index of peripheral sympathetic nerve activity. Subsequently, we identified brain regions in which the activities covaried with βart using parametric modulation analysis. The analysis result demonstrated that the lateral and medial prefrontal cortex and ventral and dorsal anterior cingulate cortex, which are included in the pain matrix, showed activities positively correlated with βart (r = 0.47, p < 0.001). βart was also significantly correlated with self-reported pain intensity (r = 0.44, p < 0.001) and applied pain intensity (r = 0.43, p < 0.001). These results indicate that peripheral arterial stiffness can be used as an objective pain evaluation metric.
Peripheral Arterial Stiffness Positively Correlates with Pain-Related Brain Activity
Peripheral Arterial Stiffness During Electrocutaneous Stimulation is Positively Correlated with Pain-related Brain Activity and Subjective Pain Intensity: An fMRI Study
Toshio Tsuji, Fumiya Arikuni, Takafumi Sasaoka, Shin Suyama, Takashi Akiyoshi, Zu Soh, Harutoyo Hirano, Ryuji Nakamura, Noboru Saeki, Masashi Kawamoto, Masao Yoshizumi, Atsuo Yoshino, and Shigeto Yamawaki
Scientific Reports, volume 11, Article number: 4425, doi.org/10.1038/s41598-021-83833-6, Published online: 24 February 2021. (SCI, IF=3.998)