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Both dorsal and ventral spinal cord pathways contribute to overground locomotion in the adult rat.
- Source :
-
Experimental neurology [Exp Neurol] 2002 Oct; Vol. 177 (2), pp. 575-80. - Publication Year :
- 2002
-
Abstract
- Identification of long tracts responsible for spontaneous locomotion is critical for spinal cord injury (SCI) repair strategies. We recently demonstrated that extensive demyelination of adult rat thoracic ventral columns, ventromedial, and ventrolateral white matter produces persistent, significant open-field hindlimb locomotor deficits. Locomotor movements resulting from stimulation of the pontomedullary locomotor region are inhibited by dorsolateral funiculus (DLF) lesions suggesting that important pathways for locomotion may also exist in the dorsal white matter. However, dorsal hemisections that interrupt dorsal columns/dorsal corticospinal tract (DC/CST) and DLF pathways do not produce persistent, severe locomotor deficits in the adult rat. We studied the contributions of myelinated tracts in the DLF and DC/CST to overground locomotion following complete conduction blockade of axons in the ventrolateral funiculus (VLF), a region important for locomotor movements and for transcranial magnetic motor-evoked potentials (tcMMEP). Animals received ethidium bromide plus photon irradiation to produce discrete demyelinating lesions sufficient to stop axonal conduction in the VLF, combined VLF + DLF, or combined VLF + DC/CST. Open-field BBB scores and tcMMEPs were studied at 1, 2, 3, and 4 weeks postlesion. VLF lesions resulted in mean BBB scores of 17 at 4 weeks. VLF + DC/CST and VLF + DLF lesions resulted in mean BBB scores of 15.9 and 11.1, respectively. TcMMEPs were absent in all lesion types confirming VLF conduction blockade throughout the study. Our data indicate that significant contributions to locomotion from myelinated pathways within the rat DLF can be revealed when combined with simultaneous compromise of the VLF.
- Subjects :
- Animals
Anterior Horn Cells drug effects
Anterior Horn Cells physiology
Anterior Horn Cells radiation effects
Axons physiology
Efferent Pathways drug effects
Efferent Pathways radiation effects
Electric Stimulation instrumentation
Electromagnetic Fields
Ethidium pharmacology
Evoked Potentials, Motor physiology
Female
Hindlimb innervation
Hindlimb physiology
Locomotion drug effects
Locomotion radiation effects
Myelin Sheath drug effects
Myelin Sheath radiation effects
Nerve Fibers, Myelinated drug effects
Nerve Fibers, Myelinated physiology
Nerve Fibers, Myelinated radiation effects
Neural Conduction drug effects
Neural Conduction radiation effects
Posterior Horn Cells drug effects
Posterior Horn Cells physiology
Posterior Horn Cells radiation effects
Rats
Rats, Inbred F344
Recovery of Function
Spinal Cord drug effects
Spinal Cord radiation effects
Efferent Pathways physiology
Locomotion physiology
Spinal Cord physiology
Subjects
Details
- Language :
- English
- ISSN :
- 0014-4886
- Volume :
- 177
- Issue :
- 2
- Database :
- MEDLINE
- Journal :
- Experimental neurology
- Publication Type :
- Academic Journal
- Accession number :
- 12429203
- Full Text :
- https://doi.org/10.1006/exnr.2002.7959