Avaliação da estabilidade cerebral e conexões intra e inter-hemisféricas na modulação afetiva da dor

Abstract

Introduction: Emotions are mental experiences in the same class as sensations, desires, or beliefs. Pain is an unpleasant experience caused by diseases, injury or emotional issues. Pain is also a sensory experience that brings affective qualities, influencing the behavioral and psychological structure of the subject. Both psychological and emotional factors are able of modulating painful perception. Dynamic functional brain networks (RFC), built through graph theory, time varying graphs (TVG), allow us to understand how the brain activity of neuronal units are coordinated and integrated. Objective: To build RFC of healthy volunteers visualizing pleasant, unpleasant, neutral images and black screen, under painful thermal induction and without painful induction, to evaluate the cerebral activity of the pain affective modulation through TVG. We wish to evaluate connectivity, cortical brain stability and intraand inter-hemispheric connections (heterophilic and homophilic) in pain, under modulation of emotions. Methods: 40 volunteers, 20 men and 20 women participated of this study. Data were collected through the EEG with 65 channels, VAS scale for pain assessment and emotional arousal. The data was filtered, and the artifacts removed automatically and then visual inspection was performed. After that, RFCs were constructed using the motifs method to extract the indexes from the network using MATLAB. Results: We found increased connectivity in right hemisphere during unpleasant images, breaking the symmetry. The brain connectivity and stability increased during painful condition, which presented lower variation of the network topology and less variation of the amount of edges. For intra and interhemisphere connections, we found increased homophily in painful condition at left hemisphere. Men and women have homophilic connections, but women were more homophilic than men. Intra and inter-hemispheric connections were altered in pain, during images viewing, alternating the interaction between the right and left hemisphere, depending on the images displayed.