Correlation between electrophysiological properties, morphological maturation, and olig gene changes during postnatal motor tract development

Jun Cai, Yi Ping Zhang, Lisa B E Shields, Zoe Z. Zhang, Naikui Liu, Xiao-Ming Xu, Shi Qing Feng, Christopher B. Shields

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

This study investigated electrophysiological and histological changes as well as alterations of myelin relevant proteins of descending motor tracts in rat pups. Motor-evoked potentials (MEPs) represent descending conducting responses following stimulation of the motor cortex to responses being elicited from the lower extremities. MEP responses were recorded biweekly from postnatal (PN) week 1 to week 9 (adult). MEP latencies in PN week 1 rats averaged 23.7 ms and became shorter during early maturation, stabilizing at 6.6 ms at PN week 4. During maturation, the conduction velocity (CV) increased from 2.8 ± 0.2 at PN week 1 to 35.2 ± 3.1 mm/ms at PN week 8. Histology of the spinal cord and sciatic nerves revealed progressive axonal myelination. Expression of the oligodendrocyte precursor markers PDGFRα and NG2 were downregulated in spinal cords, and myelin-relevant proteins such as GalC, CNP, and MBP increased during maturation. Oligodendrocyte-lineage markers Olig2 and MOG, expressed in myelinated oligodendrocytes, peaked at PN week 3 and were downregulated thereafter. A similar expression pattern was observed in neurofilament M/H subunits that were extensively phosphorylated in adult spinal cords but not in neonatal spinal cords, suggesting an increase in axon diameter and myelin formation. Ultrastructural morphology in the ventrolateral funiculus (VLF) showed axon myelination of the VLF axons (99.3%) at PN week 2, while 44.6% were sheathed at PN week 1. Increased axon diameter and myelin thickness in the VLF and sciatic nerves were highly correlated to the CV (rs > 0.95). This suggests that MEPs could be a predicator of morphological maturity of myelinated axons in descending motor tracts.

Original languageEnglish
Pages (from-to)713-722
Number of pages10
JournalDevelopmental Neurobiology
Volume73
Issue number9
DOIs
StatePublished - Sep 2013

Fingerprint

Motor Evoked Potentials
Axons
Spinal Cord
Oligodendroglia
Myelin Proteins
Genes
Sciatic Nerve
Myelin Sheath
Down-Regulation
Spinal Nerves
Intermediate Filaments
Motor Cortex
Lower Extremity
Histology

Keywords

  • Conduction velocity
  • Maturation
  • Motor-evoked potentials
  • Sciatic nerve
  • Spinal cord
  • Ventrolateral funiculus

ASJC Scopus subject areas

  • Cellular and Molecular Neuroscience
  • Developmental Neuroscience

Cite this

Correlation between electrophysiological properties, morphological maturation, and olig gene changes during postnatal motor tract development. / Cai, Jun; Zhang, Yi Ping; Shields, Lisa B E; Zhang, Zoe Z.; Liu, Naikui; Xu, Xiao-Ming; Feng, Shi Qing; Shields, Christopher B.

In: Developmental Neurobiology, Vol. 73, No. 9, 09.2013, p. 713-722.

Research output: Contribution to journalArticle

Cai, Jun ; Zhang, Yi Ping ; Shields, Lisa B E ; Zhang, Zoe Z. ; Liu, Naikui ; Xu, Xiao-Ming ; Feng, Shi Qing ; Shields, Christopher B. / Correlation between electrophysiological properties, morphological maturation, and olig gene changes during postnatal motor tract development. In: Developmental Neurobiology. 2013 ; Vol. 73, No. 9. pp. 713-722.
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abstract = "This study investigated electrophysiological and histological changes as well as alterations of myelin relevant proteins of descending motor tracts in rat pups. Motor-evoked potentials (MEPs) represent descending conducting responses following stimulation of the motor cortex to responses being elicited from the lower extremities. MEP responses were recorded biweekly from postnatal (PN) week 1 to week 9 (adult). MEP latencies in PN week 1 rats averaged 23.7 ms and became shorter during early maturation, stabilizing at 6.6 ms at PN week 4. During maturation, the conduction velocity (CV) increased from 2.8 ± 0.2 at PN week 1 to 35.2 ± 3.1 mm/ms at PN week 8. Histology of the spinal cord and sciatic nerves revealed progressive axonal myelination. Expression of the oligodendrocyte precursor markers PDGFRα and NG2 were downregulated in spinal cords, and myelin-relevant proteins such as GalC, CNP, and MBP increased during maturation. Oligodendrocyte-lineage markers Olig2 and MOG, expressed in myelinated oligodendrocytes, peaked at PN week 3 and were downregulated thereafter. A similar expression pattern was observed in neurofilament M/H subunits that were extensively phosphorylated in adult spinal cords but not in neonatal spinal cords, suggesting an increase in axon diameter and myelin formation. Ultrastructural morphology in the ventrolateral funiculus (VLF) showed axon myelination of the VLF axons (99.3{\%}) at PN week 2, while 44.6{\%} were sheathed at PN week 1. Increased axon diameter and myelin thickness in the VLF and sciatic nerves were highly correlated to the CV (rs > 0.95). This suggests that MEPs could be a predicator of morphological maturity of myelinated axons in descending motor tracts.",
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