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analyzed. Moreover, a high resolution map of the distribution of the
electrical field was produced for each component. Twenty-five
healthy volunteers (mean age: 24 years) participated. Normal
gustatory and olfactory functions were ascertained tested by means
of “Sniffin’ Sticks” and taste spray tests. Stimuli for ERP
recordings were delivered using a gustometer (GM01-Burghart
Medizintechnik, Wedel, Germany). This device is controlled by
computer, with special characteristic able to elicit ERPs (quasi-
squared pulsed stimuli, constant temperature of 38°C). Results:
Our preliminary results show a faster response related to salt
stimulation compared to sweet (ΔP1= 75±4 ms; ΔN1= 70±4 ms;
ΔP2 = 148±8 ms). The strongest response (highest peak-to-peak
amplitude) was observed for salt at the frontal position. The right
side of the brain exhibited stronger than the left side (C4 amplitude
>C3 amplitude). The topographic distribution of the potentials
shows an early positivity on the right side of the brain (P1) that
moves to the posterior with strong negativity on the frontal side
(N1). Finally the component at P2 is related with a strong positivity
in the central part of the brain (P2). Conclusions: High-resolution
gustatory ERP appears to be useful in the investigation of the
development of the central-nervous response, especially during the
early processing.
#P63
POSTER SESSION II:
TRIGEMINAL SYSTEM; TASTE CNS;
NEUROIMAGING; OLFACTION CNS
Brain correlates of mental imagery in “olfactorily” and
“auditorily” creative thinkers
Moustafa Bensafi, Pauline Joussain, Johan Poncelet,
Lauranne Przybylski, Catherine Rouby, Barbara Tillmann
Lyon Neuroscience Research Center Lyon, France
There are large individual differences in the ability to form vivid
mental images. Experience accounts for some of this variability and
its long-term effect can be seen in creative thinkers, such as Chefs
or musicians. If Chefs and musicians have respectively better
olfactory and auditory imagery ability than do lay persons, how is
such advantage reflected in brain activity? Does their expertise
transfer to imagery in other modalities, or is it modality-specific?
To test these questions, we recruited 43 participants (13 cooks,
15 musicians, 15 lay controls; mean age: 29.7+/-10.8) who
completed a 2-step imaging task: first, they read 2 words (A and B)
naming 2 fruits (or 2 musical instruments). Then, a third word (C)
was presented and participants had to decide whether the odor of
fruit C (or the timbre of instrument C) was more similar to that of
word A or B. Response times were compared between the odor (or
timbre) imagery task and a control task (size imagery of fruits or
instruments). Evoked potentials were recorded using a 64-channels
EEG system. Whereas cooks responded faster during odor imagery
than size imagery for fruits, musicians responded faster during
timbre imagery than size imagery for instruments. Controls did
not differ between these tasks. At the neural level, a hemispheric
dissociation emerged for a late positive complex (time window:
800-1200ms): (1) tasks involving mental imagery of size (fruits
or instruments) involved significantly more strongly the left
hemisphere in all three groups, (2) odor imaging recruited equally
strongly both hemispheres in cooks, (3) timbre imaging recruited
equally strongly both hemispheres in musicians. These findings
suggest that sensory experience in creative thinkers involves a
domain-specific brain modulation of mental imaging ability.
Acknowledgements: ANR-Creation: ANR-08-CREA-011
#P64
POSTER SESSION II:
TRIGEMINAL SYSTEM; TASTE CNS;
NEUROIMAGING; OLFACTION CNS
No effects of handedness on passive processing of olfactory
stimuli: an fMRI study
Marie Gottschlich
1
, Katrin Lübke
1,2
, Johannes Gerber
3
,
Bettina M. Pause
2
, Thomas Hummel
1
1
Smell & Taste Clinic, Department of Otorhinolaryngology,
University of Dresden Medical School Dresden, Germany,
2
Institute for experimental psychology, Department for Biological
Psychology and Social Psychology, Heinrich-Heine-University of
Düsseldorf Düsseldorf, Germany,
3
Department of Neuroradiology,
University of Dresden Medical School Dresden, Germany
The study aimed to investigate possible differences in lateralized
olfactory processing in left- and right-handed subjects using a
functional MRI paradigm. Twenty-four (14 female, 10 male) right
handers and 24 (14 female, 10 male) left handers participated; their
mean age was 24.0 years, all were in excellent health with no
indication of any major nasal or other health problems. The rose-
like odor phenyl ethyl alcohol and the smell of rotten eggs (H
2
S)
were used for relatively specific olfactory activation in a block
design using a 1.5 T MR scanner. Results indicated no major
differences in lateralized olfactory activation between left- and
right-handers. This suggests that in simple olfactory tasks
handedness does not seem to play a substantial role in the
processing of olfactory information.
#P65
POSTER SESSION II:
TRIGEMINAL SYSTEM; TASTE CNS;
NEUROIMAGING; OLFACTION CNS
Dynamic Behavior of fMRI BOLD Signal in Olfaction:
Curbing Habituation Effects and Identifying Associated
Olfactory Neural Networks
Prasanna R Karunanayaka
1
, Paul Eslinger
2
, Jian-Li Wang
1
,
Chris Weitekamp
1
, Kathleen Gates
3
, Peter Molenaar
3
, Qing Yang
1
1
Dept. of Radiology Hershey, PA, USA,
2
Dept. of Neurology
Hershey, PA, USA,
3
Dept. of Human Development and Family
Studies State College, PA, USA
Introduction
The study investigated patterns of spatial and
temporal BOLD signal behavior in the olfactory network of healthy
adults following presentation of multiple concentrations of
lavender. Olfactory functional activity was investigated using
converging methods of General Linear Model (GLM), Group
Independent Component Analysis (ICA), and unified Structural
Equation Modeling (uSEM). We hypothesize that specific
functional networks subserve primary perceptual as well as higher-
order olfactory-related cognitive processes.
Results
Time course
plots of average POC activity for each stimulus revealed that
different odorant strengths elicited similar BOLD effect responses.
Group ICA analysis delineated separable neuronal circuits that
were spatially centered in the primary olfactory cortex, striatum,
dorsolateral prefrontal cortex, rostral prefrontal cortex /anterior
cingulate, and parietal-occipital junction. The uSEM analysis
identified biologically plausible olfactory networks that subserve
primary perceptual as well as affective/motivational and higher-
order olfactory-related cognitive processes, with each expressing
unique spatio-temporal BOLD signal characteristics.
Conclusion
The novel olfactory stimulation paradigm greatly reduced
habituation effects and permitted the identification of five olfactory
networks. Findings were interpreted within a model that specifies
Abstracts | 49
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