Neural Mechanisms of Malodor Masking: A Wearable EEG Study

Olfactory neuroscience has uncovered much about the neural underpinnings of conscious olfactory evaluations, most particularly in relation to pleasantness. Past research have focused on how the brain responds to purely pleasant or unpleasant odors, leaving little known about the neural responses to the masking of known unpleasant stimuli (malodors) by pleasant stimuli. To address this, in the present study participants were exposed to malodor of high and low intensity, with and without a pleasant masking stimuli. Electroencephalography (EEG) analyses have revealed that malodor masking induces significant modulations in cortical activity over frontal, central and parietal cortex, supported primarily by θ and β frequency band oscillations, which likely represent attention and affective neural processing, while also involving δ and α band oscillations. The findings pave the way for EEG-based detection of malodor suppression, which can support the design of effective olfactory masking techniques to combat odor annoyance in domestic and public environments.