The nose smells what the eye sees: crossmodal visual facilitation of human olfactory perception.
Human olfactory perception is notoriously unreliable, but shows substantial benefits from visual cues, suggesting important crossmodal integration between these primary sensory modalities. We used event-related fMRI to determine the underlying neural mechanisms of olfactory-visual integration in the human brain. Subjects participated in an olfactory detection task, whereby odors and pictures were delivered separately or together. By manipulating the degree of semantic correspondence between odor-picture pairs, we show a perceptual olfactory facilitation for semantically congruent (versus incongruent) trials. This behavioral advantage was associated with enhanced neural activity in anterior hippocampus and rostromedial orbitofrontal cortex. We suggest these findings can be interpreted as indicating that human hippocampus mediates reactivation of crossmodal semantic associations, even in the absence of explicit memory processing.
Gottfried
Jay A
JA
Functional Imaging Laboratory, Wellcome Department of Imaging Neuroscience, 12 Queen Square, London WC1N 3BG, United Kingdom. j.gottfried@fil.ion.ucl.ac.uk
Dolan
Raymond J
RJ
D000328:Adult; D000679:Amygdala / Q000502:physiology; D000704:Analysis of Variance; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000502:physiology*; D003463:Cues; D004192:Discrimination, Psychological / Q000502:physiology; D005071:Evoked Potentials; D005260:Female; D007839:Functional Laterality; D006624:Hippocampus; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D009812:Odorants; D009833:Olfactory Pathways / Q000502:physiology*; D010465:Perception / Q000502:physiology*; D010775:Photic Stimulation; D011930:Reaction Time / Q000502:physiology; D012660:Semantics; D012903:Smell / Q000502:physiology*; D013268:Stimulation, Chemical; D014785:Vision, Ocular; D014796:Visual Perception / Q000502:physiology*