Odor-induced persistent neural activity in associative encoding in humans

This study explored the impact of brief exposure to odor cues on sustained neural activity during a 6-second delay period before memory encoding of a picture image. Combining univariate and multivariate ERP analytical approaches, our results align with nonhuman data, indicating that odor cues induced sustained neural activity in humans, persisting beyond the odor exposure throughout the nearly 6-second delay period. We observed higher amplitude of sustained ERPs for unpleasant compared to pleasant odor cues. Additionally, participants exhibited more confident memory recall for pictures preceded by unpleasant rather than pleasant odor cues during encoding, underscoring the influence of brief odor cues on memory formation for temporally distant events. In conclusion, this study revealed that brief exposure to odor cues induced sustained neural activity in humans, with distinct effects on memory formation along the pleasantness dimension, emphasizing the lasting impact of olfactory stimuli on cognitive processes.