EEG correlates of olfactory processing during an instructed-delay task

EEG correlates of olfaction are of fundamental and practical interest for many reasons. In the field of neural technologies, olfactory-based brain-computer interfaces (BCIs) represent an approach that could be useful for neurorehabilitation of anosmia, dysosmia and hyposmia. While the idea of a BCI that decodes neural responses to different odors and/or enables odor-based neurofeedback is appealing, the results of previous EEG investigations into the olfactory domain are rather inconsistent, particularly when non-primary processing of olfactory signals is concerned. Here we report the results from an EEG study where an olfaction-based instructed-delay task was implemented. We utilized an olfactory display and a sensor of respiration to present odors in a strictly controlled fashion. Spatio-spectral EEG properties were analyzed to assess the olfactory-related components. Under these experimental conditions, EEG components representing processing of olfactory information were found around channel C4, where changes were detected for the 12-Hz spectral component. Additionally, significant differences in EEG patterns were observed when responses to odors were compared to the responses to odorless stimuli. We conclude EEG recordings are suitable for detecting active processing of odors. As such they could be integrated in a BCI that strives to rehabilitate olfactory disabilities or uses odors for hedonistic purposes.