Odor increases synchronization of brain activity when watching emotional movies

Brain synchronicity among individuals occurs when their brain activities synchronize or align during social interactions or shared activities. This study investigated whether exposure to a pleasant odor enhances intersubject brain synchrony during emotional movie viewing, with participants serving as their own controls.

We studied the brain activity of 20 participants watching video clips in the fMRI under two conditions: with and without a positively-valenced odor. Regarding the scientific literature, the movie clips are supposed to induced brain synchronicity among participants. Comparing the synchronicity maps from both conditions allowed us to determine whether the odor enhanced brain synchronization among participants.

Exposure to a positively-valenced odor increased shared brain activity across participants, with stronger effects observed for negative movie scenes. This effect also grew over time, suggesting that odors can influence emotional and social processing in the brain.