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#P118
POSTER SESSION III:
OLFACTION DEVELOPMENT & CNS;
HUMAN PSYCHOPHYSICS; TASTE PERIPHERY
Concentration at Detection as an Inappropriate Index of
Chemosensory Potency
William S Cain
1
, J Enrique Cometto-Muñiz
1
, Michael H Abraham
2
,
Roland Schmidt
1
1
UC San Diego/Surgery La Jolla, CA, USA,
2
University College
London/Chemistry London, United Kingdom
The objective is to clarify the bases of a QSAR for odor and
irritation potency. Abraham et al. demonstrated applicability of a
linear free energy relationship (LFER) to chemesthetic/irritatiion
potency. The equation, with descriptors for excess molar refraction,
dipolarity/polarizability, hydrogen bond acidity and basicity, resp.,
and lipophilicity could account for potency to humans and various
rodents (rsq about 0.95). The generality seemed consistent with
the simplicity of chemesthesis phenomenologically and
mechanistically. When solved for odor, the variables accounted
for less variance (rsq about 0.75 to 0.80), a possible reflection of
greater complexity phenomenologically and mechanistically.
This outcome occurred previously, and did so here with data of
precision and more than 200 materials (“Nagata set”). The outcome
tempted the conclusion that chemesthetic potency depends just
upon selective factors related to transport, whereas odor potency
depends also upon specific factors such as molecular
complementarity (e.g., shape). Research on input-output functions
for individual materials suggests another possibility, viz., the two
LFERs account for the same amount of variance. Chemesthetic
output vs. an input of concentration invariably exhibits expansion
whereas olfactory output vs. input of the same variable of
concentration invariably exhibits compression. When normalized
for this, the Abraham equation can do as well for odor as for
chemesthetic detection. If residual variance of 5% is acceptable,
then we have no reason to improve the Abraham model for
olfaction, except some calculational refinements. These should
include a measure of potency other than simple concentration,
which introduces systematic variation in the chemesthetic-olfactory
comparison. Acknowledgements: Supported by NIH grants R01
DC002741, R01 DR005003, and R01 DC050602.
#P119
POSTER SESSION III:
OLFACTION DEVELOPMENT & CNS;
HUMAN PSYCHOPHYSICS; TASTE PERIPHERY
Response time for odor localization and identification
Johannes Frasnelli
1
, Luc Keita
1
, Valérie LaBuissonnière-Ariza
1,2
,
Franco Lepore
1,2
1
CERNEC, Université de Montréal Montréal, QC, Canada,
2
CHU Ste. Justine, Université de Montréal Montréal, QC, Canada
When assessing the chemical senses, researchers often measure
subjects’ ability to identify or localise odors. One method of testing
both tasks is the application of dichotomous stimuli. However, a
problem one encounters with this method is the long testing time
required to distinguish between different levels of performance; this
is especially true if one takes into consideration the long inter
stimulus interval which is needed to prevent adaptation and
habituation. In this study we investigated if response times could be
used as an alternative measure to assess odor localisation and
identification. We delivered two mixed olfactory/ trigeminal odors
(benzaldehyde - almond odor; eucalyptol - eucalyptus odor) to one
nostril in a pseudorandomized order; the other nostril received an
odor free airpuff. In half of the trials we asked the 23 normosmic
participants to localise the odors (i.e., to detect the stimulated
nostril); in the other half of the trials they were asked to identify the
odors (i.e., to indicate whether they had received the almond odor
or the eucalyptus odor). Subjects responded as fast as possible by
pressing one of two buttons, allowing us to record both response
times and response accuracy. Subjects reached a higher accuracy
for odor identification than for odor localisation (driven by the
almond odor); there was no effect on response times. We further
observed response times to be correlated to response accuracy for
the identification task, but not for the localisation task. Response
times provide parametric data and are much faster to acquire, since
less repetitions are needed. Our data therefore suggest that
measuring response times may be an alternative economic
approach to assess subjects’ ability to identify odors; this however
seems not to be true for odor localisation. Acknowledgements:
CIHR postdoctoral fellowship to JF
#P120
POSTER SESSION III:
OLFACTION DEVELOPMENT & CNS;
HUMAN PSYCHOPHYSICS; TASTE PERIPHERY
Olfactory Environment Influences Close Relationships through
Multiple Methods of Measurement
Robin J Freyberg, Melissa G Bart
Stern College for Women, Department of Psychology
New York, NY, USA
The current study examined whether disrupting the olfactory
environment would impact the interaction of pairs of close friends
through examining questionnaires, psychophysiology, and raters’
perceptions of the videotaped interactions. One hundred pairs of
female undergraduate close friends participated in two fifteen
minute videotaped interactions. The first session was established as
a baseline interaction for all participants. In the second session for
half of the pairs, one member of the dyad was given a different
perfume to wear; for the other half one participant was given a
different watch to wear as a non-olfactory control condition.
In questionnaires, only fragrance-wearing participants in the
unfamiliar fragrance condition reported lower levels of enjoyment
in the second session compared to the first, p = .004. Further,
perceptions of closeness decreased for both participants when the
olfactory environment was disrupted, p = .011. Analyses of
psychophysiology data revealed that there was a trend for a session
x condition interaction for beats per minute (BPM), p = .057. In the
fragrance conditions, participants continuing their regular fragrance
routine exhibited a decrease in BPM which was not observed in the
unfamiliar fragrance condition. Analysis of raters’ perceptions
demonstrated that there was decreased meaningfulness, intimacy,
and active engagement during the change in fragrance for both
dyad members, all p <.05. Lastly, no changes in questionnaires,
psychophysiology, or ratings of videos were observed in the
non-olfactory control condition. Such findings suggest that
exposure to the unfamiliar fragrance during the second session
dynamically and rapidly affected close relationships.
Abstracts | 67
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