Olfactory coding in the mammalian olfactory bulb

@article{Leon2003OlfactoryCI,
  title={Olfactory coding in the mammalian olfactory bulb},
  author={Michael Leon and Brett A. Johnson},
  journal={Brain Research Reviews},
  year={2003},
  volume={42},
  pages={23-32}
}
Maps of odorant molecular features in the Mammalian olfactory bulb.
TLDR
This review summarizes the emerging view of the spatial organization of the odorant receptor maps and suggests that the glomerular sheet represents the characteristic molecular features in a systematic, gradual, and multidimensional fashion.
Continuous Spatial Representations in the Olfactory Bulb may Reflect Perceptual Categories
TLDR
This work applies a statistical analysis on 2-deoxyglucose images taken over the entire bulb of glomerular layer of the rat to see how the recognition of odors in the nose is translated into a map of odor quality in the brain, and indicates that perceptual qualities could be represented as continuous spatial codes of the olfactory bulb glomerulus population.
Chemotopic odorant coding in a mammalian olfactory system
TLDR
When glomerular activity patterns are viewed relative to the overall level ofglomerular activation, the patterns accurately predict the perception of odor quality, thereby supporting the notion that spatial patterns of activity are the key factors underlying that aspect of the olfactory code.
Cluster analysis of rat olfactory bulb responses to diverse odorants.
TLDR
F fuzzy c-means clustering methods and a novel validity approach based on cluster stability are combined to evaluate the significance of the fuzzy partitions on a data set of glomerular layer responses to a large diverse group of odorants and confirm the existence ofglomerular response clusters to similar odorants.
Topographic representation of odorant molecular features in the rat olfactory bulb.
TLDR
Examination of the spatial representation of the characteristic molecular features of odorants using structurally semirigid aromatic compounds suggest a systematic and gradual change in the characteristic Molecular features according to the position of subclusters in the map.
Information processing in the mammalian olfactory system.
TLDR
Findings are presented that exemplified the high degree of olfactory plasticity, with special emphasis on the first central relay of the Olfactory system.
Spatial representations of odorants in olfactory bulbs of rats and mice: Similarities and differences in chemotopic organization
TLDR
It is concluded that clustering responses to shared odorant features may be a general strategy for odor coding but that the specific locations of high‐activity domains may be unique to a species.
Long hydrocarbon chains serve as unique molecular features recognized by ventral glomeruli of the rat olfactory bulb
TLDR
Overlaps in response profiles were observed in the patterns evoked by alkanes and by other aliphatic odorants of corresponding carbon chain length despite possessing different oxygen‐containing functional groups, which demonstrated that hydrocarbon chains could serve as molecular features in the combinatorial coding of odorant information.
Central Processing of Natural Odor Mixtures in Insects
TLDR
It is concluded that odor mixtures may be represented both at the single-neuron level and at the population level, with the former being hard-wired and the latter being more subjected to network modulation.
Normalized Neural Representations of Complex Odors
TLDR
A simple statistical model of the processing in the olfactory bulb leads to concentration-invariant, sparse representations of the odor composition, which reveals two generic consequences of global inhibition: odors with many molecular species are more difficult to discriminate and receptor arrays with heterogeneous sensitivities perform badly.
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References

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Modular representations of odorants in the glomerular layer of the rat olfactory bulb and the effects of stimulus concentration
TLDR
It is suggested that changes in modular glomerular activity patterns could underlie altered odor perception across odorant concentrations, and they provide additional support for a combinatorial, spatially based code in the olfactory system.
Spatial coding of odorant features in the glomerular layer of the rat olfactory bulb
In order to determine whether molecular features of odorants are represented spatially in the glomerular layer of the olfactory bulb, we used metabolic mapping of [14C]2‐deoxyglucose uptake in rats
Tuning and Topography in an Odor Map on the Rat Olfactory Bulb
TLDR
Several parallels to the function and architecture of the visual system that help interpret the neural representation of odors are explored, given local inhibitory circuits within the olfactory bulb, which can account for the observed functional inhibition between related odors.
Local Permutations in the Glomerular Array of the Mouse Olfactory Bulb
TLDR
This work sought to evaluate the constancy of the glomerular array in the mouse by determining the relative positions of glomeruli for various odorant receptors, using a method that affords single-axon resolution, and in a large number of bulbs.
Perceptual Correlates of Neural Representations Evoked by Odorant Enantiomers
TLDR
This study attempted to predict the perceptions of odorants from their evoked patterns of neural activity in the olfactory bulb by describing the glomerular activation patterns evoked by pairs of odorant enantiomers based on the uptake of [14C]2-deoxyglucose in the Olfactory bulbs glomerULAR layer.
Functional mapping of the rat olfactory bulb using diverse odorants reveals modular responses to functional groups and hydrocarbon structural features
TLDR
In an effort to understand the olfactory code of rats, more than 1,500,000 measurements of glomerular activity in response to 54 odorants selected to provide differences in functional groups and hydrocarbon structure revealed relationships in activation patterns between odorants of similar hydro carbon structure.
Selective imaging of presynaptic activity in the mouse olfactory bulb shows concentration and structure dependence of odor responses in identified glomeruli
TLDR
This work has taken advantage of the one-to-one correspondence of glomeruli and olfactory receptor molecules in the mouse Olfactory bulb to analyze the tuning properties of a major receptor population by high resolution calcium imaging of odor responses selectively in the presynaptic compartment ofglomeruli.
Odorant molecular length: One aspect of the olfactory code
TLDR
The data suggest that posterior portions of the bulb may encode specific steric features of odorant molecules and that some odorant features may have an inherent or acquired greater representation than do others.
Genetic tracing reveals a stereotyped sensory map in the olfactory cortex
TLDR
A stereotyped sensory map in the olfactory cortex is revealed in which signals from a particular receptor are targeted to specific clusters of neurons, permitting the parallel, and perhaps differential, processing of inputs from a single receptor before delivery to the neocortex and limbic system.
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