Odor-induced Sustained Neural Activity during Memory Encoding.

How long do the neural and cognitive effects of a brief odor experience last? This study investigated whether short exposures to pleasant and unpleasant odors can induce sustained changes in brain activity and influence memory formation for events occurring several seconds later. Using EEG, we combined univariate ERP analyses with time-resolved multivariate decoding to track neural responses during a 6-sec delay between odor presentation and visual memory encoding. We found that brief odor cues elicited sustained neural activity that persisted well beyond odor offset. Unpleasant odors, in particular, were associated with higher sustained ERP amplitudes compared with pleasant ones. Behaviorally, participants showed greater confidence in recognizing images that had been preceded by unpleasant odors, suggesting that even brief olfactory experiences can modulate memory encoding for temporally distant events. These findings demonstrate that brief olfactory cues have a lasting effect on both neural activity and subsequent memory performance.