DEVELOPMENT OF INNERVATION IN TETRAPOD LIMBS 111
movements that gradually becomes narrowed to the final pattern of
response.
4. Cell and fiber selection takes place centrally and peripherally.
Within the ventral horn there is turnover of cells which is at its height
at the time when limb movement is most rapidly developing. Furthermore, the numbers of fibers in peripheral nerves decreases during late
stages of development. In Eleutherodactylus,
this decrease is related to
loss of motor innervation of supernumerary grafted limbs.
5. In amniotes the ventral horn becomes subdivided into groups of
cells, each concerned with the innervation of a number of muscles of
similar function. In the rabbit fetus, it has been shown that during this
process of segregation, axons from each group of motor cells grow toward
and make contact with their appropriate myoblastic mass. Then follows
the development of motility in the limb, at a time which corresponds with
the peak of cell degeneration in the anuran ventral horn. The main period
of cell degeneration in the mammalian cord comes at an earlier stage
when the originally continuous ventrolateral column is broken up into
separate ventral horns for each limb.
References
Angulo y Gonzalez, A. W. (1940). J. Comp. Neurol 73, 469.
Arora, H. L., and Sperry, R. W. (1957). /. Embryol. Exptl. Morphol. 5, 256.
Barcroft, J., and Barron, D. H. (1939). J. Comp. Neurol. 70, 477.
Barron, D. H. (1941). Biol. Rev. Cambridge Phil. Soc. 16, 1.
Brookhart, J. M., and Fadiga, E. (1960). I. Physiol. (London) 150, 633.
Burckhardt, K. R. (1889). Arch. Mikroskop. Anat. Entwicklungsmech.
34, 131.
Coghill, G. E. (1929). "Anatomy and the Study of Behaviour." Cambridge Univ.
Press, London and New York.
Coronios, J. D. (1933). Genet. Psychol. Monograph 14, 283.
Detwiler, S. R. (1925). J. Comp. Neurol. 38, 461.
Detwiler, S. R. (1933). Biol. Rev. Cambridge Phil. Soc. 8, 269.
East, E. W. (1931). Anat. Record 50, 201.
Eccles, J. C. (1957). "The Physiology of Nerve Cells." Johns Hopkins Press,
Baltimore, Maryland.
Eccles, J. C. (1964). "The Physiology of Synapses." Springer, Berlin.
Fujita, S. (1964). /. Comp. Neurol. 122, 311.
Gamble, H. J. (1966). J. Anat. Lond. 100, 487.
Gray, J. (1950). Symp. Soc. Exptl. Biol. 4, 112.
Hamburger, V. (1958). Am. J. Anat. 102, 365.
Hamburger, V., and Levi-Montalcini, R. (1950). In "Genetic Neurology" (P. Weiss.
ed.), pp. 128-160. Univ. of Chicago Press, Chicago, Illinois.
Hamburger, V., Wenger, E., and Oppenheim, R. (1966). I. Exptl. Zool. 162, 133.
Harris, A. E. (1965). Ph. D. Thesis, Cambridge Univ., Cambridge, England.
Harrison, R. G. (1910). J. Exptl. Zool. 9, 787.
movements that gradually becomes narrowed to the final pattern of
response.
4. Cell and fiber selection takes place centrally and peripherally.
Within the ventral horn there is turnover of cells which is at its height
at the time when limb movement is most rapidly developing. Furthermore, the numbers of fibers in peripheral nerves decreases during late
stages of development. In Eleutherodactylus,
this decrease is related to
loss of motor innervation of supernumerary grafted limbs.
5. In amniotes the ventral horn becomes subdivided into groups of
cells, each concerned with the innervation of a number of muscles of
similar function. In the rabbit fetus, it has been shown that during this
process of segregation, axons from each group of motor cells grow toward
and make contact with their appropriate myoblastic mass. Then follows
the development of motility in the limb, at a time which corresponds with
the peak of cell degeneration in the anuran ventral horn. The main period
of cell degeneration in the mammalian cord comes at an earlier stage
when the originally continuous ventrolateral column is broken up into
separate ventral horns for each limb.
References
Angulo y Gonzalez, A. W. (1940). J. Comp. Neurol 73, 469.
Arora, H. L., and Sperry, R. W. (1957). /. Embryol. Exptl. Morphol. 5, 256.
Barcroft, J., and Barron, D. H. (1939). J. Comp. Neurol. 70, 477.
Barron, D. H. (1941). Biol. Rev. Cambridge Phil. Soc. 16, 1.
Brookhart, J. M., and Fadiga, E. (1960). I. Physiol. (London) 150, 633.
Burckhardt, K. R. (1889). Arch. Mikroskop. Anat. Entwicklungsmech.
34, 131.
Coghill, G. E. (1929). "Anatomy and the Study of Behaviour." Cambridge Univ.
Press, London and New York.
Coronios, J. D. (1933). Genet. Psychol. Monograph 14, 283.
Detwiler, S. R. (1925). J. Comp. Neurol. 38, 461.
Detwiler, S. R. (1933). Biol. Rev. Cambridge Phil. Soc. 8, 269.
East, E. W. (1931). Anat. Record 50, 201.
Eccles, J. C. (1957). "The Physiology of Nerve Cells." Johns Hopkins Press,
Baltimore, Maryland.
Eccles, J. C. (1964). "The Physiology of Synapses." Springer, Berlin.
Fujita, S. (1964). /. Comp. Neurol. 122, 311.
Gamble, H. J. (1966). J. Anat. Lond. 100, 487.
Gray, J. (1950). Symp. Soc. Exptl. Biol. 4, 112.
Hamburger, V. (1958). Am. J. Anat. 102, 365.
Hamburger, V., and Levi-Montalcini, R. (1950). In "Genetic Neurology" (P. Weiss.
ed.), pp. 128-160. Univ. of Chicago Press, Chicago, Illinois.
Hamburger, V., Wenger, E., and Oppenheim, R. (1966). I. Exptl. Zool. 162, 133.
Harris, A. E. (1965). Ph. D. Thesis, Cambridge Univ., Cambridge, England.
Harrison, R. G. (1910). J. Exptl. Zool. 9, 787.