Perceptual and processing differences between physical and dichorhinic odor mixtures.
Perceptual integration of sensory input from our two nostrils has received little attention in comparison to lateralized inputs for vision and hearing. Here, we investigated whether a binary odor mixture of eugenol and l-carvone (smells of cloves and caraway) would be perceived differently if presented as a mixture in one nostril (physical mixture), vs. the same two odorants in separate nostrils (dichorhinic mixture). In parallel, we investigated whether the different types of presentation resulted in differences in olfactory event-related potentials (OERP). Psychophysical ratings showed that the dichorhinic mixtures were perceived as more intense than the physical mixtures. A tendency for shift in perceived quality was also observed. In line with these perceptual changes, the OERP showed a shift in latencies and amplitudes for early (more "sensory") peaks P1 and N1 whereas no significant differences were observed for the later (more "cognitive") peak P2. The results altogether suggest that the peripheral level is a site of interaction between odorants. Both psychophysical ratings and, for the first time, electrophysiological measurements converge on this conclusion.
Division for Psychology, Department of Clinical Neuroscience, Karolinska Institutet, 171 77 Stockholm, Sweden. Electronic address: malin.schutze@ki.se.
M
M
Schütze
Smell and Taste Clinic, Department of Otorhinolaryngology, Technical University of Dresden Medical School, Fetscherstrasse 74, 01307 Dresden, Germany; ENT Clinic, Bern University Hospital, Switzerland.
S
S
Negoias
Division for Psychology, Department of Clinical Neuroscience, Karolinska Institutet, 171 77 Stockholm, Sweden.
M J
MJ
Olsson
Smell and Taste Clinic, Department of Otorhinolaryngology, Technical University of Dresden Medical School, Fetscherstrasse 74, 01307 Dresden, Germany.
T
T
Hummel
D000293:Adolescent; D000328:Adult; D001921:Brain / Q000502:physiology*; D005054:Eugenol; D005071:Evoked Potentials; D005260:Female; D006801:Humans; D008297:Male; D009812:Odorants; D055696:Olfactory Perception / Q000502:physiology*; D010812:Physical Stimulation; D011601:Psychophysics; D012903:Smell / Q000502:physiology*; D013997:Time Factors; D055815:Young Adult
D005054:Eugenol
OERP; odorant mixture; olfaction; olfactory event-related potential; olfactory event-related potentials; perception; quality