QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

HOME  |   SEARCH  |   ARCHIVE  |   SUBSCRIBE  |   CONTACT  |   HELP

This Article Full Text Full Text (PDF) Submit an eLetter Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (24) Citing Articles via Google Scholar Google Scholar Articles by Mears, S. C. Articles by Frank, E. Search for Related Content PubMed PubMed Citation Articles by Mears, S. C. Articles by Frank, E.

 Previous Article  |  Next Article 

Volume 17, Number 9, Issue of May 1, 1997 pp. 3128-3135
Copyright ©1997 Society for Neuroscience

Formation of Specific Monosynaptic Connections between Muscle Spindle Afferents and Motoneurons in the Mouse

Received Jan. 10, 1997; accepted Feb. 10, 1997.

Simon C. Mears and Eric Frank

Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261

In adult vertebrates, sensory neurons innervating stretch-sensitive muscle spindles make monosynaptic excitatory connections with specific subsets of motoneurons in the spinal cord. Spindle afferents (Ia fibers) make the strongest connections with motoneurons supplying the same (homonymous) muscle but make few or no connections with motoneurons supplying antagonistic or functionally unrelated muscles. In lower vertebrates these connections are specific from the time they first are formed, but there is comparatively little information about how these reflex connections form in mammals. We therefore studied the pattern of these synaptic connections during postnatal development in mice. Intracellular recordings were made from identified hindlimb motoneurons in an isolated spinal cord preparation, and monosynaptic inputs from Ia fibers in identified hindlimb muscle nerves were measured at different times during the first postnatal week. The pattern of connections was specific throughout this period. Ia fibers made strong connections with homonymous motoneurons but only weak connections with antagonistic motoneurons at every time point examined, from P0 through P7. Even when muscle nerves were stimulated at only 0.1 Hz, the pattern of connections was still highly specific, arguing against a special subpopulation of labile inappropriate connections. The absence of appreciable rearrangements in the pattern of these connections during the first postnatal week is, therefore, analogous to the situation in lower vertebrates, suggesting that mechanisms responsible for establishing this specificity have been conserved during evolution.

Key words: synaptogenesis; synaptic specificity; motoneurons; muscle spindle afferents; Ia fibers; spinal cord; stretch reflex

This article has been cited by other articles:

				Z. Wang, L. Li, M. Goulding, and E. Frank Early Postnatal Development of Reciprocal Ia Inhibition in the Murine Spinal Cord J Neurophysiol, July 1, 2008; 100(1): 185 - 196. [Abstract] [Full Text] [PDF]

				Z. Wang, L. Y. Li, M. D. Taylor, D. E. Wright, and E. Frank Prenatal Exposure to Elevated NT3 Disrupts Synaptic Selectivity in the Spinal Cord J. Neurosci., April 4, 2007; 27(14): 3686 - 3694. [Abstract] [Full Text] [PDF]

				H. Xu, A. Clement, T. M. Wright, and P. Wenner Developmental Reorganization of the Output of a GABAergic Interneuronal Circuit J Neurophysiol, April 1, 2007; 97(4): 2769 - 2779. [Abstract] [Full Text] [PDF]

				G. Z. Mentis, V. C. Siembab, R. Zerda, M. J. O'Donovan, and F. J. Alvarez Primary Afferent Synapses on Developing and Adult Renshaw Cells J. Neurosci., December 20, 2006; 26(51): 13297 - 13310. [Abstract] [Full Text] [PDF]

				A.-E. Allain, P. Meyrand, and P. Branchereau Ontogenic Changes of the Spinal GABAergic Cell Population Are Controlled by the Serotonin (5-HT) System: Implication of 5-HT1 Receptor Family J. Neurosci., September 21, 2005; 25(38): 8714 - 8724. [Abstract] [Full Text] [PDF]

				T. Sapir, E. J. Geiman, Z. Wang, T. Velasquez, S. Mitsui, Y. Yoshihara, E. Frank, F. J. Alvarez, and M. Goulding Pax6 and Engrailed 1 Regulate Two Distinct Aspects of Renshaw Cell Development J. Neurosci., February 4, 2004; 24(5): 1255 - 1264. [Abstract] [Full Text] [PDF]

				H.-H. Chen, W. G. Tourtellotte, and E. Frank Muscle Spindle-Derived Neurotrophin 3 Regulates Synaptic Connectivity between Muscle Sensory and Motor Neurons J. Neurosci., May 1, 2002; 22(9): 3512 - 3519. [Abstract] [Full Text] [PDF]

				J. C. Glover Development of Specific Connectivity Between Premotor Neurons and Motoneurons in the Brain Stem and Spinal Cord Physiol Rev, April 1, 2000; 80(2): 615 - 647. [Abstract] [Full Text] [PDF]

				W.-J. Song and F. Murakami Development of Functional Topography in the Corticorubral Projection: An In Vivo Assessment Using Synaptic Potentials Recorded from Fetal and Newborn Cats J. Neurosci., November 15, 1998; 18(22): 9354 - 9364. [Abstract] [Full Text] [PDF]

Home  |   Search  |   Archive  |   Subscribe  |   Contact  |   Help