Abstracts - Association for Chemoreception Sciences

#P61 POSTER SESSION II:
OLFACTION DEVELOPMENT; TASTE CNS;
NEUROIMAGING; OLFACTION CNS
#P62 POSTER SESSION II:
OLFACTION DEVELOPMENT; TASTE CNS;
NEUROIMAGING; OLFACTION CNS
Biochemical components of trigeminal integration in
anosmics: A pilot functional magnetic spectroscopy study
Veronika Schöpf 1 , Kathrin Kollndorfer 1 , Elisabeth Hoche 1 , Bernhard
Strasser 2 , Ksenia Kowalczyk 1 , Ewald Unger 3 , Christian A. Müller 4 ,
Siegfried Trattnig 2 , Martin Krssak 2,5
1
Department of Radiology, Division of Neuro- and Musculoskeletal
Radiology Medical University of Vienna Vienna, Austria,
2
Department of Radiology, MR Centre of Excellence, Medical
University of Vienna Vienna, Austria, 3 Center for Medical Physics
and Biomedical Engineering, Medical University of Vienna Vienna,
Austria, 4 Department of Otorhinolaryngology, Medical University
of Vienna Vienna, Austria, 5 Department of Internal Medicine III,
Division of Endocrinology and Metabolism, Medial University of
Vienna Vienna, Austria
Several studies investigated functional interaction of the olfactory
and trigeminal system. Although anosmic patients are not able to
perceive odors they show changes in “insular” blood oxygenation
during trigeminal neuronal activity. This pilot study aimed to
investigate how changes on blood oxygenation level, as observed
by fMRI, are underlined by changes in neurotransmitter (GABA,
glutamate) balance under trigeminal simulation in the insula
and how these changes differ between anosmic and healthy
populations. 3 (2f;25-43ys) functional anosmics and 8 controls
(6f;18-43ys) were examined using proton magnetic resonance
spectroscopy (1H-MRS) to explore changes of excitatory and
inhibitory neurotransmitters in the insula. Spin-echo based MRS
(TE=30ms/TR=5000ms) measurements were performed on a
3T whole body MR scanner, using a 32ch coil for signal
detection combined with a stimulation device, which was
designed specifically for intranasal application. The paradigm
consisted of 4 stimulation blocks: 4 dynamic cycles with 32
acquisitions, and 32 stimuli (CO 2
, 50%v/v, birhinal, 250ms).
Acquired spectral transients were individually frequency
corrected, phased and further grouped according to the
timeline position into baseline- and stimulation-groups. The
quantification of metabolic intensities was performed using
the LCModel with an imported modelled basis set including
metabolites and macromolecular resonances. Results for controls
revealed decreased GABA (41.24%) during the rest phase.
Anosmic patients showed a significant decrease of glutamate
(16.42%) and a higher GABA response (205.25%) rate to
stimulation compared to controls. Results of this study will
significantly contribute to the basic understanding of trigeminal
processing of chemosensory information in patients with
olfactory dysfunction. Acknowledgements: FWF (P23205-B09)
Superadditive processing during flavor perception is
modulated by anterior temporal cortex connectivity
Janina Seubert 1 , Kathrin Ohla 1,2 , Yoshiko Yokomukai 3 ,
Johan N. Lundström 1,4,5
1
Monell Chemical Senses Center Philadelphia, PA, USA,
2
German Institute of Human Nutrition Potsdam-Rehbrücke,
Germany, 3 Kirin Holdings Company LTD Tokyo, Japan,
4
Department of Psychology, University of Pennsylvania Philadelphia,
PA, USA, 5 Department of Clinical Neurosience, Karolinska Institute
Stockholm, Sweden
The combination of taste and odor found in a flavorful dish
creates a more powerful sensation than its odor or taste in
isolation. Whereas the neural processing of the individual
chemosensory components is well known, the functional
connectivity underlying the combined flavor percept is poorly
understood. In the present functional magnetic resonance
imaging study, subjects were presented with taste only
(gustatory presentation of juice, closed soft palate), smell only
(orthonasal presentation of juice odor), or a combined flavor
(retronasal-gustatory presentation, swallowing juice). As
expected, olfactory stimulation alone activated olfactory areas
while gustatory stimulation alone elicited activation within the
gustatory cortex. Overlapping activation within both networks
could be observed during flavor presentation, and a convergence
zone between all three conditions was observed in the anterior
ventral insula and cingulate cortex. Superadditive activity for the
flavor condition, relative to odor and taste alone, was observed
in the dorsal insular gyrus, extending into parietal operculum
and postcentral gyrus. Finally, to delineate the cerebral networks
contributing to the flavor percept, we assessed the functional
connectivity between these significant nodes responsive to
chemosensory overlap during combined odor-taste stimulation.
Increases in functional connectivity with both convergent and
superadditive areas were observed in an overlapping area in
the temporal pole. Taken together, these findings are suggestive
of an important relay function of semantic memory circuits
in the formation of the flavor experience from crossmodal
chemosensory information.
POSTER PRESENTATIONS
Abstracts are printed as submitted by the author(s).
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