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ANALYSIS OF THE GEOTROPIC ORIENTATION OF YOUNG RATS. IV

The geotropic orientation of young rats of a closely inbred line P, separated 6 years ago from a stock which gave rise also to the closely inbred lines A and B previously studied, has been measured. The curve connecting orientation-angle with inclination of substratum is in a general way similar to...

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Detalles Bibliográficos
Autores principales: Crozier, W. J., Pincus, G.
Formato: Texto
Lenguaje:English
Publicado: The Rockefeller University Press 1931
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2141160/
https://www.ncbi.nlm.nih.gov/pubmed/19872642
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author Crozier, W. J.
Pincus, G.
author_facet Crozier, W. J.
Pincus, G.
author_sort Crozier, W. J.
collection PubMed
description The geotropic orientation of young rats of a closely inbred line P, separated 6 years ago from a stock which gave rise also to the closely inbred lines A and B previously studied, has been measured. The curve connecting orientation-angle with inclination of substratum is in a general way similar to those for A, B, and with them differs markedly from that for race K of totally different ancestry. The variability of the response exhibits similar affinities. Although the orientation-angles are rather close to those obtained with A, the threshold slope for P is that for B; analysis of the curve discloses how this fact is related to the character of the presumptive distributions of thresholds for the respective arrays of tension-receptor units. It is pointed out that these considerations prevent loose comparisons of "geotropic sensitivity" in different lines of rats, but make it plain why comparisons in terms of thresholds for response or of magnitude of response at the same threshold are ineffective. The estimated "number of excitation units," however, is found to correspond to the variability of orientation, and to the manner and extent whereby the dispersions of the measured orientation-angles are governed by the magnitude of the gravitational vector.
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spelling pubmed-21411602008-04-23 ANALYSIS OF THE GEOTROPIC ORIENTATION OF YOUNG RATS. IV Crozier, W. J. Pincus, G. J Gen Physiol Article The geotropic orientation of young rats of a closely inbred line P, separated 6 years ago from a stock which gave rise also to the closely inbred lines A and B previously studied, has been measured. The curve connecting orientation-angle with inclination of substratum is in a general way similar to those for A, B, and with them differs markedly from that for race K of totally different ancestry. The variability of the response exhibits similar affinities. Although the orientation-angles are rather close to those obtained with A, the threshold slope for P is that for B; analysis of the curve discloses how this fact is related to the character of the presumptive distributions of thresholds for the respective arrays of tension-receptor units. It is pointed out that these considerations prevent loose comparisons of "geotropic sensitivity" in different lines of rats, but make it plain why comparisons in terms of thresholds for response or of magnitude of response at the same threshold are ineffective. The estimated "number of excitation units," however, is found to correspond to the variability of orientation, and to the manner and extent whereby the dispersions of the measured orientation-angles are governed by the magnitude of the gravitational vector. The Rockefeller University Press 1931-11-20 /pmc/articles/PMC2141160/ /pubmed/19872642 Text en Copyright © Copyright, 1931, by The Rockefeller Institute for Medical Research This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/).
spellingShingle Article
Crozier, W. J.
Pincus, G.
ANALYSIS OF THE GEOTROPIC ORIENTATION OF YOUNG RATS. IV
title ANALYSIS OF THE GEOTROPIC ORIENTATION OF YOUNG RATS. IV
title_full ANALYSIS OF THE GEOTROPIC ORIENTATION OF YOUNG RATS. IV
title_fullStr ANALYSIS OF THE GEOTROPIC ORIENTATION OF YOUNG RATS. IV
title_full_unstemmed ANALYSIS OF THE GEOTROPIC ORIENTATION OF YOUNG RATS. IV
title_short ANALYSIS OF THE GEOTROPIC ORIENTATION OF YOUNG RATS. IV
title_sort analysis of the geotropic orientation of young rats. iv
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2141160/
https://www.ncbi.nlm.nih.gov/pubmed/19872642
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