TY - JOUR
T1 - Fitting pieces in the peripheral nerve puzzle
AU - Hallin, R. G.
AU - Wu, G.
N1 - Funding Information:
This study was supported by Magnus Bergvalls Foundation, Clas Groschinskys Minnesfond, Harald Jeanssons Foundation, Harald and Greta Jeanssons Foundation, Åke Wibergs Foundation, the In-dependant Order of Odd Fellows in Stockholm, the Karolinska In-stitutet, the Swedish Society of Medicine, and the Wenner-Gren Foundation, Stockholm, Sweden, and by funds supplied by the Royal Free Hampstead and the Whittington Hospital NHS Trusts, UK. The work undertaken by R.G.H. with the Royal Free Hampstead NHS Trust received a part of its funding from the NHS Executive; the views expressed in this publication are those of the authors and not necessarily those of the Trust or the NHS Executive.
PY - 2001
Y1 - 2001
N2 - Findings from comparative microneurography are reviewed, i.e., data obtained by exploring human nerves with tungsten electrodes or concentric needle electrodes under similar conditions. It has emerged that activity in single myelinated fibers originates near nodes of Ranvier. Other data have shown that Ranvier nodes tend to cluster in certain regions of a fascicle and belong to fibers of the same modality which innervate the same skin area. This segregation involves all four main classes of myelinated low-threshold skin afferents. Fiber populations of the same modality may act as peripheral projection modules involved in somatosensory processing of tactile stimuli to cognitive levels. The fiber bundle arrangement of the nerves may be important for conserving functional gnosis in conditions where peripheral nerve fibers are lost. This organization may also be critical as a substrate to promote reinnervation after nerve cut followed by peripheral nerve suture. It is therefore less critical for an outgrowing fiber to find its exact distal counterpart. Even if misguided outgrowth occurs into the endoneurial tube of a neighboring distal fiber of the same modality with an adjacent receptive field, function can be reestablished. A precise nerve topography might also be of significance for obtaining a functionally satisfactory recovery after avulsion injuries treated by nerve root implantation into the spinal cord. Thus, there is in man an ordered nerve fiber organization, both in the periphery and in the CNS, which may have profound functional significance both under normal conditions and in disease.
AB - Findings from comparative microneurography are reviewed, i.e., data obtained by exploring human nerves with tungsten electrodes or concentric needle electrodes under similar conditions. It has emerged that activity in single myelinated fibers originates near nodes of Ranvier. Other data have shown that Ranvier nodes tend to cluster in certain regions of a fascicle and belong to fibers of the same modality which innervate the same skin area. This segregation involves all four main classes of myelinated low-threshold skin afferents. Fiber populations of the same modality may act as peripheral projection modules involved in somatosensory processing of tactile stimuli to cognitive levels. The fiber bundle arrangement of the nerves may be important for conserving functional gnosis in conditions where peripheral nerve fibers are lost. This organization may also be critical as a substrate to promote reinnervation after nerve cut followed by peripheral nerve suture. It is therefore less critical for an outgrowing fiber to find its exact distal counterpart. Even if misguided outgrowth occurs into the endoneurial tube of a neighboring distal fiber of the same modality with an adjacent receptive field, function can be reestablished. A precise nerve topography might also be of significance for obtaining a functionally satisfactory recovery after avulsion injuries treated by nerve root implantation into the spinal cord. Thus, there is in man an ordered nerve fiber organization, both in the periphery and in the CNS, which may have profound functional significance both under normal conditions and in disease.
KW - Fiber population projection
KW - Human peripheral nerve
KW - Microneurography
KW - Nerve function/regeneration
KW - Node clustering
KW - Structural and functional map
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U2 - 10.1006/exnr.2001.7813
DO - 10.1006/exnr.2001.7813
M3 - Review article
C2 - 11716573
AN - SCOPUS:0035695685
SN - 0014-4886
VL - 172
SP - 482
EP - 492
JO - Experimental Neurology
JF - Experimental Neurology
IS - 2
ER -