This Article  • References  • Full text PDF  • Reply to article  • Send to a friend  • Save in My Folder  • Save to citation manager  • Permissions  Citing Articles  • Citation map  • Citing articles on Web of Science (10)  • Contact me when this article is cited  Related Content  • Similar articles in this journal  Social Bookmarking   What's this?

The Effect of Hypoactivity and Hyperactivity

Camille B. Olson, PhD; Chester P. Swett, Jr., MD

Arch Neurol. 1969;20(3):263-270.

	Since this article does not have an abstract, we have provided the first 150 words of the full text PDF and any section headings.

PREVIOUS work from this laboratory indicates that there is a relation between the speed of contraction of a motor unit and the size of the motor neuron innervating it.^1,2 Motor units which contract rapidly and develop large amounts of tension are innervated by large motor neurons, whereas motor units which contract slowly and develop small amounts of tension are innervated by small motor neurons. Moreover, the size of a motor neuron determines its susceptibility to discharge: the smaller an anterior horn cell, the lower its threshold for excitation.³ It follows that the contraction speed of muscle fibers may be a function of the amount of contractile activity they perform. The available evidence^1-3 suggests that muscle fibers which are used intensively have slow speeds of contraction. If this inference is correct, experimental interventions which alter the amount of activity or usage of a muscle should produce changes in . . . [Full Text PDF of this Article]

Author Affiliations
From the Department of Physiology, Harvard Medical School, Boston.

Footnotes
Submitted for publication July 27, 1968; accepted Nov 18, 1968.

Reprint requests to Department of Pharmacology, Harvard Medical School, 25 Shattuck St, Boston 02115 (Dr. Olson).

CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter     What's this?