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Spinal sensorimotor transformation: Relation between cutaneous somatotopy and a reflex network

Levinsson, Anders LU ; Holmberg, Hans LU ; Broman, Jonas LU ; Zhang, Mengliang LU and Schouenborg, Jens LU (2002) In Journal of Neuroscience 22(18). p.8170-8182
Abstract
The projection of primary afferents onto spinal interneurons constitutes the first step in sensorimotor transformations performed by spinal reflex systems. Despite extensive studies on spinal somatotopy, uncertainties remain concerning the extent and significance of representational overlap and relation to spinal reflex circuits. To address these issues, the cutaneous projection from the hindpaw and its relation to the topography of lamina V neurons encoding withdrawal reflex strength ("reflex encoders") was studied in rats. Thin and coarse primary afferent terminations in laminas II and III-IV, respectively, were mapped by wheat germ agglutinin-horseradish peroxidase and choleragenoid tracing. The functional weights of these projections... (More)
The projection of primary afferents onto spinal interneurons constitutes the first step in sensorimotor transformations performed by spinal reflex systems. Despite extensive studies on spinal somatotopy, uncertainties remain concerning the extent and significance of representational overlap and relation to spinal reflex circuits. To address these issues, the cutaneous projection from the hindpaw and its relation to the topography of lamina V neurons encoding withdrawal reflex strength ("reflex encoders") was studied in rats. Thin and coarse primary afferent terminations in laminas II and III-IV, respectively, were mapped by wheat germ agglutinin-horseradish peroxidase and choleragenoid tracing. The functional weights of these projections were characterized by mapping nociceptive and tactile field potentials and compared with the topography of reflex encoders. Both anatomical and physiological data indicate that thin and coarse skin afferent input is spatially congruent in the horizontal plane. The representation of the hindpaw in the spinal cord was found to be intricate, with a high degree of convergence between the projections from different skin sites. "Somatotopic disruptions" such as the representation of central pads medial to that of the digits were common. The weight distribution of the cutaneous convergence patterns in laminas III-IV was similar to that of lamina V reflex encoders. This suggests that the cutaneous convergence and features such as somatotopic disruptions have specific relations to the sensorimotor transformations performed by reflex interneurons in the deep dorsal horn. Hence, the spinal somatotopic map may be better understood in light of the topography of such reflex systems. (Less)
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author
organization
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type
Contribution to journal
publication status
published
subject
keywords
reflex, spinal cord, somatosensory, receptive field, somatotopic, sensorimotor, primary afferent
in
Journal of Neuroscience
volume
22
issue
18
pages
8170 - 8182
publisher
Society for Neuroscience
external identifiers
  • pmid:12223571
  • wos:000177916000038
  • scopus:0037107128
ISSN
1529-2401
language
English
LU publication?
yes
id
9e24d780-4682-4b05-94ba-d6107c247be1 (old id 329127)
alternative location
http://www.jneurosci.org.ludwig.lub.lu.se/cgi/reprint/22/18/8170
date added to LUP
2007-10-31 10:51:19
date last changed
2017-11-26 03:20:09
@article{9e24d780-4682-4b05-94ba-d6107c247be1,
  abstract     = {The projection of primary afferents onto spinal interneurons constitutes the first step in sensorimotor transformations performed by spinal reflex systems. Despite extensive studies on spinal somatotopy, uncertainties remain concerning the extent and significance of representational overlap and relation to spinal reflex circuits. To address these issues, the cutaneous projection from the hindpaw and its relation to the topography of lamina V neurons encoding withdrawal reflex strength ("reflex encoders") was studied in rats. Thin and coarse primary afferent terminations in laminas II and III-IV, respectively, were mapped by wheat germ agglutinin-horseradish peroxidase and choleragenoid tracing. The functional weights of these projections were characterized by mapping nociceptive and tactile field potentials and compared with the topography of reflex encoders. Both anatomical and physiological data indicate that thin and coarse skin afferent input is spatially congruent in the horizontal plane. The representation of the hindpaw in the spinal cord was found to be intricate, with a high degree of convergence between the projections from different skin sites. "Somatotopic disruptions" such as the representation of central pads medial to that of the digits were common. The weight distribution of the cutaneous convergence patterns in laminas III-IV was similar to that of lamina V reflex encoders. This suggests that the cutaneous convergence and features such as somatotopic disruptions have specific relations to the sensorimotor transformations performed by reflex interneurons in the deep dorsal horn. Hence, the spinal somatotopic map may be better understood in light of the topography of such reflex systems.},
  author       = {Levinsson, Anders and Holmberg, Hans and Broman, Jonas and Zhang, Mengliang and Schouenborg, Jens},
  issn         = {1529-2401},
  keyword      = {reflex,spinal cord,somatosensory,receptive field,somatotopic,sensorimotor,primary afferent},
  language     = {eng},
  number       = {18},
  pages        = {8170--8182},
  publisher    = {Society for Neuroscience},
  series       = {Journal of Neuroscience},
  title        = {Spinal sensorimotor transformation: Relation between cutaneous somatotopy and a reflex network},
  volume       = {22},
  year         = {2002},
}