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primary and secondary levels of olfactory processing. The
converging analyses fit well with the recently proposed concept of
“
olfactory objects
” and provide a basis to investigate how these
objects may be mapped at different levels of perceptual processing
and anatomical activity. Acknowledgements: National Institute of
Aging, R01-AG027771
#P66
POSTER SESSION II:
TRIGEMINAL SYSTEM; TASTE CNS;
NEUROIMAGING; OLFACTION CNS
Olfactory habituation in the human brain
Jianli Wang
1
, Xiaoyu Sun
1
, Megha Patel
1
, Sarah Ryan
1
,
Zachary Herse
1
, Qing X. Yang
1,2
1
Penn State College of Medicine/Radiology Hershey, PA, USA,
2
Penn State College of Medicine/Neurosurgery Hershey, PA, USA
A thorough understanding of the dynamic behavior of the blood-
oxygen-level-dependent (BOLD) signal due to habituation in the
central olfactory system is essential for clinical applications of
olfactory functional magnetic resonance imaging. In this study, we
characterized the dynamic behavior of the BOLD signal in the
primary olfactory cortex and related structures when subjected to
odor habituation. Responding to 60 second prolonged odorant
presentations, the primary olfactory cortex showed a transient,
strong activation followed by a weakened but sustained activation
until the odorant was undetectable by the subjects. The activation in
the secondary olfactory structures all followed similar signal-time
course, including such structures as the orbitofrontal cortex, insular
cortex, prefrontal cortex, supramarginal cortex, precuneus cortex,
and anterior and posterior cingulate cortex. Short-term olfactory
habituation that happened within seconds and was fully recovered
in less than 98 second. These results suggest that the olfactory
habituation in the various brain structures follows the same
mechanism, which may be controlled by the primary olfactory
cortex. Acknowledgements: This study was supported in part by the
Pennsylvania Department of Health and NIH RO1 EB00454.
#P67
POSTER SESSION II:
TRIGEMINAL SYSTEM; TASTE CNS;
NEUROIMAGING; OLFACTION CNS
Complexity of odorant structure influences human olfactory
cortex activity: an fMRI study
Caroline Sezille
1
, Amandine Chakirian
1
, Marc Thevenet
1
,
Johannes Gerber
2
, Thomas Hummel
2
, Moustafa Bensafi
1
1
Lyon Neuroscience Research Center, CNRS Lyon, France,
2
University of Dresden Medical School Dresden, Germany
An important issue in olfaction research is to relate percept to the
molecular structure of stimuli. Previous studies attempted to relate
odor quality to the odorant’s physicochemical parameters. Recently,
we showed a quantitative structure-odor relationship in which the
more structurally complex a monomolecular odorant, the more
numerous the olfactory notes it evokes (Kermen et al., 2011). The
present study examined how such quantitative structure/percept
relationship was reflected in the human olfactory system. To this
end, twenty-one participants were stimulated with low (guaiacol,
isoamyle acetate) and high complexity odorants (R-limonene and
terpinenol). Responses were assessed by fMRI (1.5T -Siemens
Sonata; slices: 26; FOV: 19.2cm; Matrix: 64x64; TR: 3sec; TE:
45ms; FA: 90°; Voxel size: 3x3x3mm). Stimuli were delivered to
the subjects using an air-dilution olfactometer (1.5 l/min); after the
functional scans, participants were to estimate intensity,
pleasantness, familiarity of the stimuli and the number of olfactory
notes: whereas low and high complexity odorants were assessed
with the same intensity, pleasantness and familiarity (p>.05 in all
cases), the latter induced more olfactory notes than the former
(p=.015). A preliminary analysis performed on the imaging data
using SPM8 and Activis revealed significantly greater piriform
activation for high than low complexity odorants. Taken together,
these findings suggest that molecular complexity provides a
framework to explain both the subjective experience of smells
and its neural processing in primary olfactory cortex.
Kermen, F.
et al. Sci. Rep. 1, 206; DOI:10.1038/srep00206 (2011).
Acknowledgements: Region Rhone-Alpes CIBLE 2011 ANR
EMCO - ICEO Project
#P68
POSTER SESSION II:
TRIGEMINAL SYSTEM; TASTE CNS;
NEUROIMAGING; OLFACTION CNS
Food craving studied by combined visual and olfactory
stimulation
Megha M Patel
1
, Susan K Lemieux
2
, Stephen J Wilson
3
,
Rebecca L Corwin
4
, John E Hayes
5
, Joseph Stitt
2
, Anna S Engels
2,3
,
Jianli Wang
1
, Jeff Vesek
1
, Qing X Yang
1.6
1
Dept. of Radiology Hershey, PA, USA,
2
Social, Life, & Engineering
Science Center State College, PA, USA,
3
Dept. of Psychology State
College, PA, USA,
4
Dept. of Nutritional Sciences State College, PA,
USA,
5
Dept. of Food Science State College, PA, USA,
6
Dept. of
Neurosurgery Hershey, PA, USA
Tasting, smelling, and seeing food combine to provide an
experience that triggers our reward system. It has been
demonstrated that the taste of food, especially sweet food, evokes
activation in the caudate, putamen, and orbitofrontal cortex when
compared to a tasteless solution. It has also been shown that just
seeing and smelling food can cause craving. In this study we
combined congruent olfactory and visual cues for a more reliable
response than either might provide alone to examine if the degree
of food craving was correlated to activation in the reward system.
We used functional magnetic resonance imaging (fMRI) to study
blood oxygen level dependent (BOLD) signal change in the reward
system during presentation of the stimuli. During the paradigm,
subjects also rated how much they wanted to eat the food after each
stimuli presentation. Five subjects performed two runs for a total of
ten runs. The data showed intense global activation in the brain and
specifically in the putamen, caudate, insula, orbitofrontal cortex,
and anterior cingulate (
p
<0.001) that correlated to when the subject
really wanted the food. We also examined if visual-olfactory cue
presentation would activate the reward areas as well as the insula as
is seen in taste fMRI studies. When all stimuli were averaged for all
five subjects (
p
<0.005), activation was observed in the insula,
operculum, anterior and posterior cingulate, caudate, and putamen.
These preliminary data suggest that the level of food craving is
highly correlated to brain activation in the reward system when an
olfactory and visual food stimulus is combined. Furthermore, it
appears that olfaction with visual stimuli triggers areas, specifically
reward areas, which are similar to those stimulated by taste stimuli.
Acknowledgements: Supported by the Penn State Social Sciences
Research Institute and, in part, under a grant with the Pennsylvania
Department of Health using Tobacco CURE Funds. The
Department specifically disclaims responsibility for any analyses,
interpretations or conclusions.
50 | AChemS Abstracts 2012
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