Intracranial Recordings During Down-Regulation of Positive Emotions

Our study aimed to examine the neurophysiological markers of positive emotion downregulation. Participants of the study were epileptic patients who underwent a neurosurgical implantation of intracranial electrodes. We recorded brain activity while participants viewed one-minute positive and neutral videos, applying one of the down-regulation strategies (reappraisal and suppression) or just watching. We analyzed intracranial recording for each downregulation strategy, as well as for the control condition (watching a neutral movie) for hippocampus and amygdala. We found a significant difference in the power of the theta frequency band in the right amygdala between “watch-neutral” and “reappraise-positive” conditions as well as between “watch-positive” and “suppress-positive” conditions with higher theta band power for “watch” conditions. Behavioral assessment revealed significant difference between conditions. However, no broadband spectrum differences were found between other conditions and other brain regions. Surprisingly, the power profile of right hemisphere was not significantly different from the power profile of the left hemisphere. We assume that our analysis revealed potential differences (observed on behavioral level), which are not apparent on the sensor level analysis, requiring to continue the study with connectivity analysis.