Abstracts - Association for Chemoreception Sciences

P O S T E R S
#P3 POSTER SESSION I: TASTE IMAGING &
PSYCHOPHYSICS; CENTRAL TASTE;
MULTIPLE MODALITIES; CENTRAL &
PERIPHERAL OLFACTION
Effects of BMI on fMRI Activation to a Pleasant Taste During
Hedonic Evaluation in Older Adults
Erin R Green 1 , Aaron Jacobson 2 , Lori Haase 1 , Claire Murphy 1,2,3
1
SDSU/UCSD Joint Doctoral Program in Clinical Psychology
San Diego, CA, USA, 2 San Diego State University San Diego, CA,
USA, 3 UCSD School of Medicine, Department of Head and Neck
Surgery San Diego, CA, USA
Although obesity is currently recognized as a global health
epidemic, little attention has been directed to the rising prevalence
of obesity in the fastest growing segment of the population, older
adults. The objective of the current analysis was to investigate
associations between body mass index (BMI) and fMRI activation
to a pleasant taste during a hedonic evaluation task. Twenty
healthy older adults (ages 65+) were recruited from the
community and were screened for exclusionary criteria including
dementia, ageuesia, and anosmia. Participants fasted for 12 hours
prior to being scanned, during which time they received 8 separate
administrations of a .64M sucrose solution separated by water
rinses. T2*-weighted echo planar images were acquired using an
event-related paradigm on a 3T GE Signa EXCITE Short-Bore
research scanner. Data were processed using both whole brain and
region of interest analyses, and systematic associations between
BMI and fMRI activation to sucrose were found for both
analyses. Specifically, BMI was negatively correlated with
activation of the insula, nucleus accumbens and caudate nucleus.
Although little is known about how reward processing of foodrelated
stimuli is altered during the aging process, these data
indicate a strong association between decreased activation of
reward regions and greater amounts of body fat in otherwise
healthy older adults. Further research is warranted to investigate
whether decreased activation of the reward system may precede
weight gain, or if food-related stimuli become less rewarding after
an unhealthy accumulation of abdominal fat. Exploring
relationships between chemosensory processing and levels of
body fat in older adults may aid in increasing understanding of
age-related nutritional problems and changes in eating behavior.
Acknowledgements: Supported by NIH Grant #1 R01 AG04085
to C.M.
#P4 POSTER SESSION I: TASTE IMAGING &
PSYCHOPHYSICS; CENTRAL TASTE;
MULTIPLE MODALITIES; CENTRAL &
PERIPHERAL OLFACTION
Neuroanatomical correlates: psychophysical evaluation of
different taste qualities during hunger and satiety
Lori Haase 1,2 , Barbara Cerf-Ducastel 2 , Erin Green 1,2 ,
Aaron Jacobson 2 , Claire Murphy 1,2,3
1
SDSU/UCSD JDP Clinical Psychology San Diego, CA, USA,
2
SDSU Psychology Department San Diego, CA, USA, 3 Division of
Head and Neck Surgery, UCSD, School of Medicine San Diego,
CA, USA
The physiological states of hunger and satiety moderate brain
activation in response to taste and flavor stimuli. We have shown
that the psychophysical evaluation of taste stimuli influences the
pattern of cortical activation. That is, different brain areas are
involved in the evaluation of pleasantness (PL) relative to the
evaluation of intensity (INT). fMRI was utilized to examine the
patterns of cortical activation involved in psychological evaluation
of PL and INT during hunger and satiety in response to 2 taste
stimuli (sucrose and caffeine). During scanning, subjects were
administered taste stimuli and were asked to evaluate the
perceived PL or INT using the general Labeled Magnitude Scale.
Image analysis was conducted using AFNI. A multiple linear
regression was conducted to examine the potential relationships
between perceived PL and INT of the taste stimuli and cortical
activation. We have observed that during the PL evaluation, there
are robust correlations between perceived PL and activation
within the OFC. There was a positive correlation between PL and
OFC activation for sucrose when hungry and negative correlation
when sated; this effect is less robust for caffeine and relationships
were positive across physiological conditions. In contrast, INT
evaluation was associated with activation within the insula. Here
we show that this relationship varies as a function of stimulus and
physiological condition. There was a positive correlation between
perceived INT and insula activation for sucrose when sated and
for caffeine when hungry. These findings shed light on the impact
of qualitative features on brain activation during psychophysical
evaluation and may contribute to understanding the neural
mechanisms of eating termination and over consumption.
Supported by NIH grant AG04085 to C.M.
#P5 POSTER SESSION I: TASTE IMAGING &
PSYCHOPHYSICS; CENTRAL TASTE;
MULTIPLE MODALITIES; CENTRAL &
PERIPHERAL OLFACTION
Validation of PROP Taste Strips for the NIH Toolbox
Initiative
Hetvi Desai 1 , Susan E. Coldwell 2 , James W. Griffith 3 , Lloyd
Hastings 4 , Gregory S. Smutzer 1
1
Biology Department, Temple University Philadelphia, PA, USA,
2
Dental Public Health Sciences, University of Washington Seattle,
WA, USA, 3 Department of Medical Social Sciences, Northwestern
University Chicago, IL, USA, 4 Osmic Enterprises, Inc. Cincinnati,
OH, USA
The goal of this study was to validate the use of edible taste strips
for examining 6-n-propylthiouracil (PROP) bitter taste function
in humans. This validation was carried out by presenting
participants with taste strips that contained either 400 or 600
nmoles of PROP and asking them to report on the intensity and
hedonics of the perceived taste. Taste intensity values for PROP
strips were compared to PROP and NaCl solutions according to
Tepper et al. (Physiol. & Behav., 2001). These results were then
compared to genotype analysis of the TAS2R38 bitter taste
receptor gene. This gene exhibits variations at three distinct
nucleotide sites, which directly affect PROP taster status.
Participants with PAV/PAV or PAV/AVI genotypes were readily
able to discriminate PROP strips from control strips, and detected
PROP strips as bitter tasting. For PROP tasters (PAV/PAV or
PAV/AVI genotypes), 400 nmole PROP strips resulted in
generalized Labeled Magnitude Scale (gLMS; 0-100 scale) average
values of 35, whereas taste intensity values for 600 nmole PROP
strips averaged 40 on the gLMS. Non-tasters (AVI/AVI) averaged
10 on the gLMS for the 400 and 14 for the 600 nmole PROP
strips. Average intensity ratings for 3.20 mMolar PROP solution
by tasters was slightly higher (54) than for PROP taste strips,
while average gLMS rating for 0.32 mMolar PROP solution by
tasters was comparable to strips (33). Hedonics values were based
on a three-face scale, and PROP tasters showed a dislike for both
28 | AChemS Abstracts 2010 Abstracts are printed as submitted by the author(s)