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A Star in the Brainstem Reveals the First Step of Cortical Magnification

A fundamental question in the neurosciences is how central nervous system (CNS) space is allocated to different sensory inputs. Yet it is difficult to measure innervation density and corresponding representational areas in the CNS of most species. These measurements can be made in star-nosed moles (...

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Detalles Bibliográficos
Autores principales: Catania, Kenneth C., Leitch, Duncan B., Gauthier, Danielle
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2011
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3139641/
https://www.ncbi.nlm.nih.gov/pubmed/21811600
http://dx.doi.org/10.1371/journal.pone.0022406
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author Catania, Kenneth C.
Leitch, Duncan B.
Gauthier, Danielle
author_facet Catania, Kenneth C.
Leitch, Duncan B.
Gauthier, Danielle
author_sort Catania, Kenneth C.
collection PubMed
description A fundamental question in the neurosciences is how central nervous system (CNS) space is allocated to different sensory inputs. Yet it is difficult to measure innervation density and corresponding representational areas in the CNS of most species. These measurements can be made in star-nosed moles (Condylura cristata) because the cortical representation of nasal rays is visible in flattened sections and afferents from each ray can be counted. Here we used electrophysiological recordings combined with sections of the brainstem to identify a large, visible star representation in the principal sensory nucleus (PrV). PrV was greatly expanded and bulged out of the brainstem rostrally to partially invade the trigeminal nerve. The star representation was a distinct PrV subnucleus containing 11 modules, each representing one of the nasal rays. The 11 PrV ray representations were reconstructed to obtain volumes and the largest module corresponded to ray 11, the mole's tactile fovea. These measures were compared to fiber counts and primary cortical areas from a previous investigation. PrV ray volumes were closely correlated with the number of afferents from each ray, but afferents from the behaviorally most important, 11(th) ray were preferentially over-represented. This over-representation at the brainstem level was much less than at the cortical level. Our results indicate that PrV provides the first step in magnifying CNS representations of important afferents, but additional magnification occurs at higher levels. The early development of the 11(th), foveal appendage could provide a mechanism for the most important afferents to capture the most CNS space.
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spelling pubmed-31396412011-08-02 A Star in the Brainstem Reveals the First Step of Cortical Magnification Catania, Kenneth C. Leitch, Duncan B. Gauthier, Danielle PLoS One Research Article A fundamental question in the neurosciences is how central nervous system (CNS) space is allocated to different sensory inputs. Yet it is difficult to measure innervation density and corresponding representational areas in the CNS of most species. These measurements can be made in star-nosed moles (Condylura cristata) because the cortical representation of nasal rays is visible in flattened sections and afferents from each ray can be counted. Here we used electrophysiological recordings combined with sections of the brainstem to identify a large, visible star representation in the principal sensory nucleus (PrV). PrV was greatly expanded and bulged out of the brainstem rostrally to partially invade the trigeminal nerve. The star representation was a distinct PrV subnucleus containing 11 modules, each representing one of the nasal rays. The 11 PrV ray representations were reconstructed to obtain volumes and the largest module corresponded to ray 11, the mole's tactile fovea. These measures were compared to fiber counts and primary cortical areas from a previous investigation. PrV ray volumes were closely correlated with the number of afferents from each ray, but afferents from the behaviorally most important, 11(th) ray were preferentially over-represented. This over-representation at the brainstem level was much less than at the cortical level. Our results indicate that PrV provides the first step in magnifying CNS representations of important afferents, but additional magnification occurs at higher levels. The early development of the 11(th), foveal appendage could provide a mechanism for the most important afferents to capture the most CNS space. Public Library of Science 2011-07-19 /pmc/articles/PMC3139641/ /pubmed/21811600 http://dx.doi.org/10.1371/journal.pone.0022406 Text en Catania 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
Catania, Kenneth C.
Leitch, Duncan B.
Gauthier, Danielle
A Star in the Brainstem Reveals the First Step of Cortical Magnification
title A Star in the Brainstem Reveals the First Step of Cortical Magnification
title_full A Star in the Brainstem Reveals the First Step of Cortical Magnification
title_fullStr A Star in the Brainstem Reveals the First Step of Cortical Magnification
title_full_unstemmed A Star in the Brainstem Reveals the First Step of Cortical Magnification
title_short A Star in the Brainstem Reveals the First Step of Cortical Magnification
title_sort star in the brainstem reveals the first step of cortical magnification
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3139641/
https://www.ncbi.nlm.nih.gov/pubmed/21811600
http://dx.doi.org/10.1371/journal.pone.0022406
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