The neural cascade of olfactory processing: A combined fMRI-EEG study

Yuri Masaoka, Ian Herbert Harding, Nobuyoshi Koiwa, Masaki Yoshida, Ben J Harrison, Valentina Lorenzetti, Masahiro Ida, Masahiko Izumizaki, Christos Pantelis, Ikuo Homma

Research output: Contribution to journalArticleResearchpeer-review

16 Citations (Scopus)


Olfaction is dependent on respiration for the delivery of odorants to the nasal cavity. Taking advantage of the time-locked nature of inspiration and olfactory processing, electroencephalogram dipole modeling (EEG/DT) has previously been used to identify a cascade of inspiration-triggered neural activity moving from primary limbic olfactory regions to frontal cortical areas during odor perception. In this study, we leverage the spatial resolution of functional magnetic resonance imaging (fMRI) alongside the temporal resolution of EEG to replicate and extend these findings. Brain activation identified by both modalities converged within association regions of the orbitofrontal cortex that were activated from approximately 150-300. ms after inspiration onset. EEG/DT was additionally sensitive to more transient activity in primary olfactory regions, including the parahippocampal gyrus and amygdala, occurring approximately 50. ms post-inspiration. These results provide a partial validation of the spatial profile of the olfactory cascade identified by EEG source modeling, and inform novel future directions in the investigation of human olfaction
Original languageEnglish
Pages (from-to)71 - 77
Number of pages7
JournalRespiratory Physiology & Neurobiology
Publication statusPublished - 2014

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