AUTHOR=Lyu Yuanyuan , Zidda Francesca , Radev Stefan T. , Liu Hongcai , Guo Xiaoli , Tong Shanbao , Flor Herta , Andoh Jamila 

TITLE=Gamma Band Oscillations Reflect Sensory and Affective Dimensions of Pain

JOURNAL=Frontiers in Neurology

VOLUME=Volume 12 - 2021

YEAR=2022

URL=https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2021.695187

DOI=10.3389/fneur.2021.695187

ISSN=1664-2295

ABSTRACT=Pain is a multidimensional process, which can be modulated by emotions, however, the mechanisms underlying this modulation are yet to be fully clarified. We used pictures with different categories of emotional valence (negative, positive, neutral) as primes and applied electrical painful stimuli as targets to healthy participants. Pain intensity and unpleasantness ratings as well as electroencephalographic recordings (EEG) were made. We found that pain unpleasantness, but not pain intensity ratings were modulated by emotional pictures, with increased ratings for negative and decreased ratings for positive pictures. We also found two consecutive gamma band oscillations (GBOs) related to pain processing from time frequency analyses of the EEG signals. An early GBO had a cortical distribution contralateral to the painful stimulus, and its amplitude was positively correlated with intensity and unpleasantness ratings, but not with prime valence. The late GBO had a centroparietal distribution and its amplitude was larger for negative compared to neutral and positive pictures. The emotional modulation effect (negative versus positive) of the late GBO amplitude was positively correlated with pain unpleasantness. The early GBO might reflect the overall pain perception, possibly involving the thalamocortical circuit, while the late GBO might be related to the affective modulation of pain and top-down processes.