Ivan Ninenko ^1* Alexandra Medvedeva ² Victoria L Efimova ³ Daria Kleeva ^1,2 Marina Morozova ² Mikhail A Lebedev ^4,5

• ¹ National Research University Higher School of Economics, Moscow, Russia
• ² V. Zelman Center for Neurobiology and Brain Rehabilitation, Skolkovo Institute of Science and Technology, Moscow, Moscow Oblast, Russia
• ³ Herzen State Pedagogical University of Russia, Saint Petersburg, Russia
• ⁴ Lomonosov Moscow State University, Moscow, Moscow, Russia
• ⁵ Institute of Evolutionary Physiology and Biochemistry (RAS), Saint Petersburg, Russia

This perspective considers the novel concept of olfactory neurofeedback (O-NFB) within the framework of brain-computer interfaces (BCIs), where olfactory stimuli are integrated in various BCI control loops. In particular, electroencephalography (EEG)-based O-NFB systems are capable of incorporating different components of complex olfactory processing --from simple discrimination tasks to using olfactory stimuli for rehabilitation of neurological disorders. Thus, in In our own work, EEG theta and alpha rhythms were probed as control variables for O-NFB. Additionaly, and we developed an olfactory-based instructed-delay task. We suggest that the unique functions of olfaction offer numerous medical and consumer applications where O-NFB is combined with sensory inputs of other modalities within a BCI framework to engage brain plasticity. We discuss the ways O-NFB could be implemented, including the integration of different types of olfactory displays in the experiment set-up and EEG features to be utilized. We emphasize the importance of synchronizing O-NFB with respiratory rhythms, which are known to influence EEG patterns and cognitive processing. Overall, we expect that O-NFB systems will contribute to both practical applications in the clinical world and the basic neuroscience of olfaction.