Pain is a subjective and multidimensional experience, encompassing the sensory-discriminative, affective-motivational, and cognitive-evaluative dimensions. Acute pain is adaptive and protects individuals from further damage. However, chronic pain is often maladaptive and leads to functional neuroplasticity changes and structural reorganization. We focus on primary dysmenorrhea (PDM), which is menstrual pain in the absence of identifiable pathology. The dual characteristics of PDM thus serves as a genuine clinical model of chronic pain.
Functionally, pain perception occurs in the brain and emerges from neural information processing at varying spatial and temporal scales. By using nonlinear multiscale sample entropy (MSE) analysis, we studied the irregularity/uncertainty of brain signals across different time scales, which can be regarded as brain complexity and reflects the adaptability of the nervous system. Loss of complexity is thus considered as a representation of pathologic dynamics.
In this talk, I will first introduce chronic pain, the clinical significance of studying primary dysmenorrhea (PDM), and the use of PDM as a clinical model of chronic pain. Secondly, I will outline our recent findings on genetic neuroimaging studies in PDM. Lastly, I will briefly share the perspectives from pain experts and the International Association for the Study of Pain (IASP) on the search for human pain biomarkers.