Abstracts - Association for Chemoreception Sciences

#P102 POSTER SESSION II:
OLFACTION DEVELOPMENT; TASTE CNS;
NEUROIMAGING; OLFACTION CNS
Blend Processing by Protocerebral Neurons of Manduca sexta
Hong Lei, Hong-Yan Chiu, John Hildebrand
University of Arizona/Department of Neuroscience Tucson, AZ, USA
The male moths of Manduca sexta are more attracted to a mimic
of its natural female sex pheromones, composing of only two
essential components in a ratio that is found in its natural
pheromones. Deviation from this ratio causes reduced behavior.
The projection neurons innervating the pheromone responsive
region of the male antennal lobe produce maximal synchronized
spiking activity in response to blends consisting of the two
components centering around the natural ratio, leading to a
hypothesis that blend ratios are encoded in neuronal synchrony.
To test this hypothesis, we investigated the physiological and
morphological features of down-stream protocerebral neurons
that were challenged with stimulation of single pheromone
components and their blend of different ratios. We found a small
proportion of protocerebral neurons showing stronger responses
to the blend of natural ratio whereas many other neurons
did not distinguish these blends at all. In a multi-dimensional
analysis, we also found the population response mapped onto
the second principle axis displayed most distinction among the
two pheromone components and their blend, and the distinction
occurred prior to the peak population response - a result
consistent with an earlier observation where neural synchrony in
the antennal lobe tends to maximize before the firing rate reaches
its peak. Moreover, the response patterns of protocerebral
neurons are very diverse, indicating the complexity of internal
representation of odor stimuli at the level of protocerebrum.
Acknowledgements: This work was supported by NSF grant
DMS-1200004 to HL, NIH grant R01-DC-02751 to JGH
#P103 POSTER SESSION II:
OLFACTION DEVELOPMENT; TASTE CNS;
NEUROIMAGING; OLFACTION CNS
Comparison of changes in odor-induced firing of mitral cells
and oscillations in the local field potentials in mice learning
to discriminate odors
Anan Li, Diego Restrepo
Department of Cell and Developmental Biology, Rocky Mountain
Taste and Smell Center and Neuroscience Program Aurora, CO, USA
Odor induced mitral cell firing and changes in local field
potentials (LFPs) are modified as an animal learns to
discriminate between odors. In previous work we reported that
as the animal learns to discriminate between odors in go-no go
odor discrimination tasks synchronized unit firing of mitral cells
develop divergent responses to rewarded and unrewarded odors,
and convey important information on odor quality in addition to
odor identity in awake behaving mice (Doucette et. al. Neuron
69, 1176–1187, 2011). LFPs reflect integrated signals from cell
ensembles also show divergent responses. However, how mitral
cell firing and local LFPs are related and more importantly how
these are related on a trial-by-trial basis when the animal makes
mistakes remains to be elucidated. Here our preliminary data
indicate that unit firing and beta oscillations of LFPs (10-35
Hz) show related changes during the learning process of the
go-no go task: at the beginning of the task, there is no or very
weak divergent odor responses for both signals, while obvious
and strong divergent responses are found as the mice learn to
discriminate the odor pairs. Acknowledgements: DC00566
and DC04657
#P104 POSTER SESSION II:
OLFACTION DEVELOPMENT; TASTE CNS;
NEUROIMAGING; OLFACTION CNS
Identification of Microglia in the Peripheral Deafferentation
Response of the Adult Zebrafish Olfactory Bulb
Amanda K McKenna, Christine A Byrd-Jacobs
Western Michigan University/Biological Sciences Kalamazoo, MI, USA
Our lab has been examining the potential role of microglia in
the deafferentation response of the zebrafish olfactory bulb. We
previously used phagocytosis-dependent labeling with DiA to
illustrate the putative microglial response following olfactory
organ ablation. DiA-labeled puncta in the deafferented olfactory
bulb increased dramatically in number and then diminished over
the course of a week. The labeling pattern corresponded directly
to areas of the bulb with damaged axons. In that study, we were
unable to identify the labeled profiles conclusively as microglia.
The current study seeks to confirm both the presence and active
role of microglia in the deafferented zebrafish olfactory bulb
using an antibody to zebrafish microglia (anti-4C4). Zebrafish
were treated either with cautery ablation or Triton X-100
application to the olfactory organ to cause either permanent or
temporary deafferentation of the bulb. We hypothesized that the
pattern of anti-4C4 labeling would mimic the pattern seen with
DiA. We found that the olfactory bulb had an obvious increase
in 4C4-positive microglia 1 day following both permanent and
temporary treatments. These 4C4-positive profiles had primarily
amoeboid morphology; they were found throughout the bulb
layers but were concentrated around the degenerating axons.
Over the next several days, the 4C4-positive microglia appeared
to decrease in number; they also changed to mostly ramified
morphologies. This pattern overlaps with the DiA results but also
appears to show additional microglia not actively phagocytizing
axonal debris. Thus, there is a profound microglial response
immediately after both permanent and temporary deafferentation
in the adult zebrafish olfactory bulb that sharply declines over
the next several days. Acknowledgements: Supported by NIH-
NIDCD #011137 (CBJ)
POSTER PRESENTATIONS
Abstracts are printed as submitted by the author(s).
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