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Development of human precision grip

Development of human precision grip 221 106 106 3 3 Ann-Christin Eliasson Hans Forssberg Komei Ikuta Ingmari Apel Göran Westling Roland Johansson Department of Woman and Child Health and Department of Neuroscience, Karolinska Institute Karolinska Hospital S-17176 Stockholm Sweden Department of Physiology Umeå University S-90187 Umeå Sweden Abstract When an object held by a precision grip is subjected to an abrupt vertical load perturbation, somatosensory input from the digits triggers an increase in grip force to restore an adequate safety margin, preventing frictional slips. In adults the response occurs after a latency of 60–80 ms. In the present study, children from 2 years old upward and adults grasped and lifted an object using a precision grip. Sudden, unpredicted increases in load force (tangential to the grip surfaces) were induced by the experimenter by dropping a small disc on to a receptacle attached to the object. The impact elicited a grip force response which in young children had a longer latency and a smaller amplitude than was seen in adults. The grip response latency gradually become shorter and its amplitude increased with increasing age, reaching adult values at 6–10 years. The muscle activity underlying the response could have several bursts. The adults showed one brisk response, appearing 40–50 ms after impact, in extrinsic and intrinsic hand muscles, while younger children also exhibited a short-latency burst, appearing about 20 ms after impact. It is suggested that the short-latency response was mediated via spinal pathways, and that these pathways are disengaged by supraspinal centers during development. In a predictable loading situation, when subjects dropped the disc themselves into the receptacle using the contralateral hand, they changed strategy. Adults induced a well-timed anticipatory grip force increase prior to the impact that was scaled to the weight of the object. The youngest children did not time the force increase properly in relation to the impact. Yet, they could scale their anticipatory grip force increase with respect to the weight of the dropped disc. This suggests a well-developed capacity to use information about the weight of objects held by one hand to parameterize a programmed force output to the other hand. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Experimental Brain Research Springer Journals

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References (47)

Publisher
Springer Journals
Copyright
Copyright © 1995 by Springer-Verlag
Subject
Biomedicine; Neurosciences; Neurology
ISSN
0014-4819
eISSN
1432-1106
DOI
10.1007/BF00231065
Publisher site
See Article on Publisher Site

Abstract

221 106 106 3 3 Ann-Christin Eliasson Hans Forssberg Komei Ikuta Ingmari Apel Göran Westling Roland Johansson Department of Woman and Child Health and Department of Neuroscience, Karolinska Institute Karolinska Hospital S-17176 Stockholm Sweden Department of Physiology Umeå University S-90187 Umeå Sweden Abstract When an object held by a precision grip is subjected to an abrupt vertical load perturbation, somatosensory input from the digits triggers an increase in grip force to restore an adequate safety margin, preventing frictional slips. In adults the response occurs after a latency of 60–80 ms. In the present study, children from 2 years old upward and adults grasped and lifted an object using a precision grip. Sudden, unpredicted increases in load force (tangential to the grip surfaces) were induced by the experimenter by dropping a small disc on to a receptacle attached to the object. The impact elicited a grip force response which in young children had a longer latency and a smaller amplitude than was seen in adults. The grip response latency gradually become shorter and its amplitude increased with increasing age, reaching adult values at 6–10 years. The muscle activity underlying the response could have several bursts. The adults showed one brisk response, appearing 40–50 ms after impact, in extrinsic and intrinsic hand muscles, while younger children also exhibited a short-latency burst, appearing about 20 ms after impact. It is suggested that the short-latency response was mediated via spinal pathways, and that these pathways are disengaged by supraspinal centers during development. In a predictable loading situation, when subjects dropped the disc themselves into the receptacle using the contralateral hand, they changed strategy. Adults induced a well-timed anticipatory grip force increase prior to the impact that was scaled to the weight of the object. The youngest children did not time the force increase properly in relation to the impact. Yet, they could scale their anticipatory grip force increase with respect to the weight of the dropped disc. This suggests a well-developed capacity to use information about the weight of objects held by one hand to parameterize a programmed force output to the other hand.

Journal

Experimental Brain ResearchSpringer Journals

Published: Jan 1, 1995

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