2009 Abstracts - Association for Chemoreception Sciences

#P278 Poster session VI: Chemosensory developmentand Psychophysics ICrossmodal interactions between odors and abstract symbolsHan-Seok Seo 1 , Artin Arshamian 1,2 , Kerstin Schemmer 3 , IngeborgScheer 4 , Thorsten Sander 3 , Guido Ritter 3 , Thomas Hummel 11Smell and Taste Clinic, University of Dresden Medical SchoolDresden, Germany, 2 Department of Psychology, StockholmUniversity Stockholm, Sweden, 3 Department of Home Economicsand Nutrition Science, Münster University of Applied SciencesMünster, Germany, 4 Dasign GmbH Darmstadt, GermanySo far, in many crossmodal studies between vision and olfaction,verbal labels, colors, or pictures have been used as visual cues, allof which elicit strong contextual backgrounds, whereas little isknown about the relationship between abstract symbols andodors. The aim of this study was to investigate the crossmodalassociation of an “abstract symbol,” designed for representationof an odor, with its corresponding odor. In other words, weexplored the application of an abstract symbol for expression ofan odor via an extension of the Stroop effect (congruence/incongruence paradigm). Based on the result of an odor-symbolassociation test, two abstract symbols associated with rose orcheese odor were selected. Two different odors representing“rose” and “cheese” were applied with three types of visual cues(blank screen, and two abstract symbols for rose and cheeseodors, respectively), followed by psychometric ratings (olfactoryintensity and hedonic response) and recording of event-relatedpotentials. When the odors were presented with their congruentabstract symbols, the hedonic responses of rose and cheese odorswere most pleasant for rose odor and most unpleasant for cheeseodor. The event-related potential latencies of peaks were also theshortest at all electrode sites tested on condition that the cheeseodor was provided with its congruent symbol. In conclusion, ourfindings demonstrate that an abstract symbol may affect olfactoryperception, and indirectly suggest that an abstract symbol couldrepresent its corresponding odor.#P279 Poster session VI: Chemosensory developmentand Psychophysics IHow big is the gap between detection and recognition ofaliphatic aldehydes?Matthias Laska, Anna RinghLinkoping University Linkoping, SwedenIt is widely agreed that two different measures of olfactorysensitivity can be distinguished: a detection threshold, defined asthe lowest concentration at which an odorant can be detected ordiscriminated from a blank stimulus, and a recognition threshold,defined as the lowest concentration at which an odorant can beassigned a recognizable quality or discriminated from anotherodorant. It is further widely agreed that the detection threshold islower than the recognition threshold. Surprisingly few studies,however, have investigated the magnitude of the difference inconcentration between olfactory detection and recognitionthresholds. It was therefore the aim of the present study todetermine olfactory detection thresholds for five aliphaticaldehydes (C4-C8) in a group of 16 human subjects, and to assessthe ability of the same subjects to discriminate between the sameodorants presented at different concentrations above theirindividual detection thresholds. We found that as a group thesubjects significantly discriminated between 4 of the 10 odorantpairs when presented at a factor of 100, and 7 of the 10 odorantpairs when presented at a factor of 1000 above the individualdetection thresholds. The 3 remaining odorant pairs were notdiscriminated above chance level even when presented at a factorof 1000 above detection threshold. However, single subjectssuccessfully discriminated between certain aldehyde pairspresented at a factor as low as 3 above detection threshold.Further, a significant negative correlation between discriminationperformance and structural similarity of the aldehydes tested wasfound. The results demonstrate that the gap between detectionand recognition of aliphatic aldehydes is odorant pair-dependentbut – at the group level – spans at least a factor of 100.#P280 Poster session VI: Chemosensory developmentand Psychophysics IComparison of odor threshold for phenylethylalcoholand butanolFranziska Krone, Kornelia Lange, Ilona Croy, Thomas Hummel1 Dresden, GermanyAim of the study was to compare the results of odor thresholdtest using different number of dilution steps, separately forbutanol and phenylethylalcohol (PEA). A total of 125 subjectsparticipated (30 patients with olfactory dysfunction, 95normosmic controls). In 2 sessions the olfactory threshold forbutanol and PEA was examined with 8 (wide step method) and 16(narrow step method) dilutions using felt tip pens. Test time wasshortened by approximately 2 minutes and remained moreconstant when using the wide step method. Butanol and the PEAthreshold were not significantly different; in addition, a significantcorrelation was found between thresholds for the two odors(r=0.57, p