Abstracts - Association for Chemoreception Sciences

F344 rats on a two-odor discrimination task. Six odorants
(1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol and
1-octanol) were arranged to produce 30 novel odorant pairs
differing between one and five carbon atoms; testing sessions
included presentation of only one randomly assigned pair daily
(200 trials daily). Results showed that, although rats learned
to discriminate between any two odorant pairs, discrimination
accuracy changed systematically with carbon chain length
difference. Error patterns were remarkably consistent across
animals, such that marked increases in misses and false alarms
were indicated for pairs differing by one or two carbon atoms.
Across all odorant pairs, these effects were most pronounced
during the first 20 trials. Notably, the greatest degree of
perceptual confusion was displayed for two pairs differing by a
single carbon atom, 1-propanol/1-butanol and 1-heptanol/1-
hexanol. These data provide further support for carbon chain
length as an important odorant stimulus dimension for study of
olfactory receptor interaction (Johnson and Leon, 2000) as well
as demonstrate how hierarchical chemotopic organization of
the olfactory bulb may be reflected perceptually. Furthermore,
development of an animal model using the carbon chain
paradigm may be useful for assessing the mechanisms underlying
olfactory dysfunction.
#P210 POSTER SESSION IV:
CHEMICAL SIGNALING AND BEHAVIOR;
ANIMAL BEHAVIOR/PSYCHOPHYSICS;
CHEMOSENSATION AND METABOLISM;
VOMERONSASAL AND CHEMICAL
COMMUNICATION
The Gustatory Stop-Signal Task: A Method for Measuring
Taste Quality Discrimination in Mice with Millisecond
Temporal Resolution
Dustin M Graham, David L Hill
UVA/Psychology Charlottesville, VA, USA
There is a lack of consensus regarding the roles of temporal and
spatial coding of taste quality in the gustatory system due in
part to various experimental and analytical differences among
previous studies. Quantitative behavioral analysis can be used
to test for the cognitive principle of speed-accuracy tradeoff
(SAT), a hallmark of temporal processing of sensory stimuli.
However, current methods used to study taste perception
in rodents are temporally too slow for precise reaction-time
measurements required to test for SAT in the gustatory system.
We designed a novel behavioral paradigm, the Gustatory Stop-
Signal Task, in head-restrained mice for measuring perceptual
identification of taste stimuli with millisecond temporal
resolution. Using this new paradigm, we will apply threshold
psychophysics to determine if a stimulus-dependent SAT is
present during discrimination of basic tastes. This will provide
crucial behavioral evidence for the potential roles of temporal
and spatial coding strategies underlying taste quality coding in
the gustatory system. Additionally, the task can be combined
with advanced physiological techniques, such as visually guided
whole-cell patch-clamp recordings in sub-regions of gustatory
cortex. The gustatory stop-signal task in head-restrained mice
will provide a new foundation to combine precise quantitative
behavioral measurements of taste perception alongside state-ofthe-art
in vivo physiology. Acknowledgements: NIH Grants R01
DC00407 and F32 DC012461 - 01A1
#P211 POSTER SESSION IV:
CHEMICAL SIGNALING AND BEHAVIOR;
ANIMAL BEHAVIOR/PSYCHOPHYSICS;
CHEMOSENSATION AND METABOLISM;
VOMERONSASAL AND CHEMICAL
COMMUNICATION
Free Access to Highly Palatable Food during Adolescence
Increases Anxiety- and Depression-like Behaviors in Males,
but not in Females
Jeong-Won Jahng, Jin-Young Kim, Joo-Young Lee, Jong-Ho Lee
Seoul National University School of Dentistry Seoul, South Korea
We have reported that a long-term access to highly palatable food
(HPF) modulates the hypothalamic-pituitary-adrenal (HPA) axis
response to restraint stress in adult male rats. Psycho-emotional
disorders frequently involve dysfunctions in the HPA axis
activity. In this study, male and female SD rats had free choices
of chocolate cookies as HPF and chow with ad libitum access
from PND 28, and then were subjected to behavioral tests at
youth. Control group received chow only, and food conditions
were continued throughout the whole experimental period. Body
weight gain and daily caloric intake did not differ between HPF
and control groups both in males and females. Total ambulatory
activity was decreased with HPF access in females, but not in
males. However, HPF increased anxiety related behaviors in
males; i.e. increased rostral grooming and decreased the open
arms stay during elevated plus maze test, but did not affect
those indexes in females. Immobility duration during forced
swim test was significantly increased with HPF access in males,
but the increase was not reached to a statistical significance in
females. Stress-induced corticosterone increase was shortened
with HPF access both in males and females. Results suggest that
adolescence free access to highly palatable food may lead to a
dysfunction in the HPA axis activity both in males and females;
however, its psycho-emotional outcome be worse in males.
Acknowledgements: Supported by MOEST(2009K001269 2010-
0003642)
POSTER PRESENTATIONS
Abstracts are printed as submitted by the author(s).
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