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Brain Processing of Biologically Relevant Odors in the Awake Rat, as Revealed by Manganese-Enhanced MRI

BACKGROUND: So far, an overall view of olfactory structures activated by natural biologically relevant odors in the awake rat is not available. Manganese-enhanced MRI (MEMRI) is appropriate for this purpose. While MEMRI has been used for anatomical labeling of olfactory pathways, functional imaging...

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Autores principales: Lehallier, Benoist, Rampin, Olivier, Saint-Albin, Audrey, Jérôme, Nathalie, Ouali, Christian, Maurin, Yves, Bonny, Jean-Marie
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2012
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3485357/
https://www.ncbi.nlm.nih.gov/pubmed/23119035
http://dx.doi.org/10.1371/journal.pone.0048491
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author Lehallier, Benoist
Rampin, Olivier
Saint-Albin, Audrey
Jérôme, Nathalie
Ouali, Christian
Maurin, Yves
Bonny, Jean-Marie
author_facet Lehallier, Benoist
Rampin, Olivier
Saint-Albin, Audrey
Jérôme, Nathalie
Ouali, Christian
Maurin, Yves
Bonny, Jean-Marie
author_sort Lehallier, Benoist
collection PubMed
description BACKGROUND: So far, an overall view of olfactory structures activated by natural biologically relevant odors in the awake rat is not available. Manganese-enhanced MRI (MEMRI) is appropriate for this purpose. While MEMRI has been used for anatomical labeling of olfactory pathways, functional imaging analyses have not yet been performed beyond the olfactory bulb. Here, we have used MEMRI for functional imaging of rat central olfactory structures and for comparing activation maps obtained with odors conveying different biological messages. METHODOLOGY/PRINCIPAL FINDINGS: Odors of male fox feces and of chocolate flavored cereals were used to stimulate conscious rats previously treated by intranasal instillation of manganese (Mn). MEMRI activation maps showed Mn enhancement all along the primary olfactory cortex. Mn enhancement elicited by male fox feces odor and to a lesser extent that elicited by chocolate odor, differed from that elicited by deodorized air. This result was partly confirmed by c-Fos immunohistochemistry in the piriform cortex. CONCLUSION/SIGNIFICANCE: By providing an overall image of brain structures activated in awake rats by odorous stimulation, and by showing that Mn enhancement is differently sensitive to different stimulating odors, the present results demonstrate the interest of MEMRI for functional studies of olfaction in the primary olfactory cortex of laboratory small animals, under conditions close to natural perception. Finally, the factors that may cause the variability of the MEMRI signal in response to different odor are discussed.
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spelling pubmed-34853572012-11-01 Brain Processing of Biologically Relevant Odors in the Awake Rat, as Revealed by Manganese-Enhanced MRI Lehallier, Benoist Rampin, Olivier Saint-Albin, Audrey Jérôme, Nathalie Ouali, Christian Maurin, Yves Bonny, Jean-Marie PLoS One Research Article BACKGROUND: So far, an overall view of olfactory structures activated by natural biologically relevant odors in the awake rat is not available. Manganese-enhanced MRI (MEMRI) is appropriate for this purpose. While MEMRI has been used for anatomical labeling of olfactory pathways, functional imaging analyses have not yet been performed beyond the olfactory bulb. Here, we have used MEMRI for functional imaging of rat central olfactory structures and for comparing activation maps obtained with odors conveying different biological messages. METHODOLOGY/PRINCIPAL FINDINGS: Odors of male fox feces and of chocolate flavored cereals were used to stimulate conscious rats previously treated by intranasal instillation of manganese (Mn). MEMRI activation maps showed Mn enhancement all along the primary olfactory cortex. Mn enhancement elicited by male fox feces odor and to a lesser extent that elicited by chocolate odor, differed from that elicited by deodorized air. This result was partly confirmed by c-Fos immunohistochemistry in the piriform cortex. CONCLUSION/SIGNIFICANCE: By providing an overall image of brain structures activated in awake rats by odorous stimulation, and by showing that Mn enhancement is differently sensitive to different stimulating odors, the present results demonstrate the interest of MEMRI for functional studies of olfaction in the primary olfactory cortex of laboratory small animals, under conditions close to natural perception. Finally, the factors that may cause the variability of the MEMRI signal in response to different odor are discussed. Public Library of Science 2012-10-31 /pmc/articles/PMC3485357/ /pubmed/23119035 http://dx.doi.org/10.1371/journal.pone.0048491 Text en © 2012 Lehallier et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Lehallier, Benoist
Rampin, Olivier
Saint-Albin, Audrey
Jérôme, Nathalie
Ouali, Christian
Maurin, Yves
Bonny, Jean-Marie
Brain Processing of Biologically Relevant Odors in the Awake Rat, as Revealed by Manganese-Enhanced MRI
title Brain Processing of Biologically Relevant Odors in the Awake Rat, as Revealed by Manganese-Enhanced MRI
title_full Brain Processing of Biologically Relevant Odors in the Awake Rat, as Revealed by Manganese-Enhanced MRI
title_fullStr Brain Processing of Biologically Relevant Odors in the Awake Rat, as Revealed by Manganese-Enhanced MRI
title_full_unstemmed Brain Processing of Biologically Relevant Odors in the Awake Rat, as Revealed by Manganese-Enhanced MRI
title_short Brain Processing of Biologically Relevant Odors in the Awake Rat, as Revealed by Manganese-Enhanced MRI
title_sort brain processing of biologically relevant odors in the awake rat, as revealed by manganese-enhanced mri
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3485357/
https://www.ncbi.nlm.nih.gov/pubmed/23119035
http://dx.doi.org/10.1371/journal.pone.0048491
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