Journal article
Morphometric analysis of neuromuscular topography in the serratus anterior muscle
Muscle & nerve, Vol.33(3), pp.398-408
03/2006
Handle:
https://hdl.handle.net/2376/103988
PMID: 16320309
Abstract
Groups of neurons form ordered topographic maps on their targets, and defining the mechanisms that develop such maps, and re-connect them after disruption, has biological as well as clinical importance. The neuromuscular system is an accessible and well-studied model for defining the principles that guide map formation, both during its development and its reformation after motor nerve damage. We present evidence for the expression of this map at the level of nerve terminal morphology and muscle fiber type in the serratus anterior muscle. Morphometric analyses indicate, first, a rostrocaudal difference in nerve terminal size depending on the ventral root of origin of the axons. Second, motor endplates are larger on type IIB than type IIA muscle fibers. Third, whereas IIB muscle fibers are distributed rather evenly along the rostrocaudal axis of the muscle, the more rostral type IIB fibers are preferentially innervated by anteriorly derived (C6) motor neurons, and more caudal IIB fibers are preferentially innervated by posteriorly derived (C7) motor neurons. This inference is supported by analysis of the size of nerve terminals formed in each muscle sector by rostral and caudal roots, and by evidence that the larger terminals are on IIB fibers. These results demonstrate a subcellular expression of neuromuscular topography in the serratus anterior muscle (SA) muscle in the form of differences in nerve terminal size. These results provide deeper insights into the organization of a neuromuscular system. They also offer a rationale for a topographic map, that is, to allow spinal motor centers to activate selectively different compartments within a muscle.
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Details
- Title
- Morphometric analysis of neuromuscular topography in the serratus anterior muscle
- Creators
- S Potluri - WWAMI (Washington, Wyoming, Alaska, Montana, Idaho) Medical Program, P.O. Box 444207, University of Idaho, Moscow, Idaho 83844-4207, USAS J LampaA S NortonM B Laskowski
- Publication Details
- Muscle & nerve, Vol.33(3), pp.398-408
- Academic Unit
- Integrative Physiology and Neuroscience, Department of
- Publisher
- United States
- Grant note
- P20RR16454 / NCRR NIH HHS R01NS27024 / NINDS NIH HHS
- Identifiers
- 99900546525501842
- Language
- English
- Resource Type
- Journal article