Abstracts - Association for Chemoreception Sciences

#P212 POSTER SESSION IV:
CHEMICAL SIGNALING AND BEHAVIOR;
ANIMAL BEHAVIOR/PSYCHOPHYSICS;
CHEMOSENSATION AND METABOLISM;
VOMERONSASAL AND CHEMICAL
COMMUNICATION
#P213 POSTER SESSION IV:
CHEMICAL SIGNALING AND BEHAVIOR;
ANIMAL BEHAVIOR/PSYCHOPHYSICS;
CHEMOSENSATION AND METABOLISM;
VOMERONSASAL AND CHEMICAL
COMMUNICATION
Licking Microstructure Reveals Rapid Attenuation of
Neophobia
Kevin J Monk, Benjamin D Rubin, Jennifer Keene, Donald B Katz
Brandeis University Waltham, MA, USA
Neophobia—the initial hesitation that many animals show to a
novel food—is typically measured by comparing consumption
in the first and second sessions of access to the taste; lower
consumption in session 1 denotes neophobia, and higher 2ndsession
consumption denotes attenuation of neophobia (AN).
AN is thought to represent a bona fide example of learning—
neural plasticity induced by an association between the taste and
a safe outcome on session 1 changes the response to the tastant
during session 2. Such long-term plasticity processes require time
to complete, and thus AN should only stabilize 90 min or more
following the first exposure to the tastant—a prediction that has
been borne out in behavioral data. It remains possible, however,
that a more rapidly developing AN might escape detection
in time-averaged accounts of behavior such as consumption.
With this in mind, we performed a comparison of AN in two
contexts, a two-bottle test and a brief access test (which allowed
a real-time analysis of licking microstructure). At the level of
overall consumption, data from the two tasks were in good
accord—both revealed AN to 28mM saccharin but not to 2.8mM
saccharin. Additionally, however, the brief access task revealed
an initial hesitation to consume the higher concentration
saccharin solution; this seemingly neophobia-related hesitation
not only decreased between sessions 1 and 2, but also decreased
linearly across the twenty minutes of session ; that is, AN began
within minutes of the rats’ first exposure to the taste. These
data validate the brief-access task as an paradigm with which to
measure AN, and also reveal aspects of AN—perhaps related
to short-term plasticity—that appear within minutes of the first
taste. Acknowledgements: National Institutes of Health, World
of Work Fellowship
Channelrhodopsin Mice use Temporal Information Encoded
in the Olfactory Bulb for Odor Sensation.
Michelle R. Rebello 1,2 , Thomas S. McTavish 2 , David C. Willhite 1,2 ,
Gordon M. Shepherd 2 , Justus V. Verhagen 1,2
1
John B. Pierce Laboratory New Haven, CT, USA, 2 Yale School of
Medicine, Dept. of Neurobiology New Haven, CT, USA
Odor information is represented by spatio-temporal maps in the
olfactory bulb (OB). Spatial maps reflect the converging axons
of olfactory receptor neurons activated by odors, onto their
respective glomeruli in the OB. The origins of temporal patterns
of glomerular activation are less well understood, but odorant
receptor affinity as well as odorant sorption kinetics across
the olfactory epithelium could underlie temporal parameters
such as onset latency and rise time. Consistent differences in
response dynamics across glomeruli have been found for odorevoked
responses in the OB. Further, we have shown, using
optical imaging that retronasal and orthonasal bulbar reponses
differ in response amplitude as well as temporal dynamics. It
is therefore evident that rich temporal information is available
in the bulbar response. However it is not known whether these
temporally dynamic responses are behaviorally relevant. Using
transgenic mice expressing ChR2 under the Thy-1 promoter in
the mitral cells and a digital micromirror device to project snifftriggered
light patterns onto the dorsal OB we are able to exert
tight spatio-temporal control over OB activity patterns. We find
that mice trained on a go/no-go task are able to discriminate
patterns that are spatially identical but differ temporally. By
varying the relative delay among the same regions activated by
light patterns we are able to determine the threshold of temporal
discrimination. We find that Thy-1 ChR2 but not wild-type
mice can make temporal discriminations of less than 30ms.
Our optogenetic study confirms that awake, behaving mice
can use temporal information encoded in the bulbar response.
This suggests that temporal coding can contribute to retronasal
and orthonasal odor sensation. Acknowledgements: This work
is supported by NIH/NIDCD Grants R01DC009994 and
R01DC011286 and NIH Institutional Training Grant T15-
LM007056 from the National Library of Medicine.
POSTER PRESENTATIONS
Abstracts are printed as submitted by the author(s).
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