 |
|||||
|
|||||
|
|||||
|
|||||
|
|||||
Previous Article | Next Article
The Journal of Neuroscience, April 1, 2003, 23(7):2789
Spinal Cats on the Treadmill: Changes in Load Pathways
Marie-Pascale Côté, Ariane Ménard, and Jean-Pierre Gossard Centre de Recherche en Sciences Neurologiques, Département de Physiologie, Faculté de Médecine, Université de Montréal, Montréal, Québec, Canada H3C 3J7
Treadmill training and clonidine, an
-2 noradrenergic agonist, have been shown to improve locomotion after spinal cord injury. We speculate that transmission in load pathways, which are involved in body support during stance, is specifically modified by training. This was evaluated by comparing two groups of spinal cats; one group (n = 11) was trained to walk until full-weight-bearing (3-4 weeks), and the other (shams; n = 7) was not. During an acute experiment, changes in group I pathways, monosynaptic excitation, disynaptic inhibition, and polysynaptic excitation were investigated by measuring the response amplitude in extensor motoneurons before and after clonidine injection. Monosynaptic excitation was not modified by clonidine but was decreased significantly by training. Disynaptic inhibition was significantly decreased by clonidine in both groups, but more significantly in trained cats, and significantly reduced by training after clonidine. Also, clonidine could reverse group IB inhibition into polysynaptic excitation in both groups but more frequently in trained cats. We also investigated whether fictive stepping revealed additional changes. In trained cats, the phase-dependent modulation of all three responses was similar to patterns reported previously, but in shams, modulation of monosynaptic and polysynaptic responses was not. Overall, training appears to decrease monosynaptic excitation and enhance the effects of clonidine in the reduction of disynaptic inhibition and reversal to polysynaptic excitation. Because it is believed that polysynaptic excitatory group I pathways transmit locomotor drive to extensor motoneurons, we suggest that the latter changes would facilitate the recruitment of extensor muscles for recovering weight-bearing during stepping.
Key words: locomotion; weight-bearing; treadmill training; reflex pathways; spinalization; motor control
Copyright © 2003 Society for Neuroscience 0270-6474/03/2372789-08$05.00/0
This article has been cited by other articles:
A. Frigon and J.-P. Gossard
Asymmetric control of cycle period by the spinal locomotor rhythm generator in the adult cat
J. Physiol., October 1, 2009; 587(19): 4617 - 4628.
[Abstract] [Full Text] [PDF]
A. Frigon and S. Rossignol
Adaptive changes of the locomotor pattern and cutaneous reflexes during locomotion studied in the same cats before and after spinalization
J. Physiol., June 15, 2008; 586(12): 2927 - 2945.
[Abstract] [Full Text] [PDF]
G. Barriere, H. Leblond, J. Provencher, and S. Rossignol
Prominent Role of the Spinal Central Pattern Generator in the Recovery of Locomotion after Partial Spinal Cord Injuries
J. Neurosci., April 9, 2008; 28(15): 3976 - 3987.
[Abstract] [Full Text] [PDF]
M. D. Kubasak, D. L. Jindrich, H. Zhong, A. Takeoka, K. C. McFarland, C. Munoz-Quiles, R. R. Roy, V. R. Edgerton, A. Ramon-Cueto, and P. E. Phelps
OEG implantation and step training enhance hindlimb-stepping ability in adult spinal transected rats
Brain, January 1, 2008; 131(1): 264 - 276.
[Abstract] [Full Text] [PDF]
S. Rossignol, M. Schwab, M. Schwartz, and M. G. Fehlings
Spinal Cord Injury: Time to Move?
J. Neurosci., October 31, 2007; 27(44): 11782 - 11792.
[Abstract] [Full Text] [PDF]
V. S. Boyce, M. Tumolo, I. Fischer, M. Murray, and M. A. Lemay
Neurotrophic Factors Promote and Enhance Locomotor Recovery in Untrained Spinalized Cats
J Neurophysiol, October 1, 2007; 98(4): 1988 - 1996.
[Abstract] [Full Text] [PDF]
J. C. Petruska, R. M. Ichiyama, D. L. Jindrich, E. D. Crown, K. E. Tansey, R. R. Roy, V. R. Edgerton, and L. M. Mendell
Changes in Motoneuron Properties and Synaptic Inputs Related to Step Training after Spinal Cord Transection in Rats
J. Neurosci., April 18, 2007; 27(16): 4460 - 4471.
[Abstract] [Full Text] [PDF]
L.L Cai, G Courtine, A.J Fong, J.W Burdick, R.R Roy, and V.R Edgerton
Plasticity of functional connectivity in the adult spinal cord
Phil Trans R Soc B, September 29, 2006; 361(1473): 1635 - 1646.
[Abstract] [Full Text] [PDF]
S. Rossignol
Plasticity of connections underlying locomotor recovery after central and/or peripheral lesions in the adult mammals
Phil Trans R Soc B, September 29, 2006; 361(1473): 1647 - 1671.
[Abstract] [Full Text] [PDF]
G. Courtine, R. R. Roy, J. Raven, J. Hodgson, H. Mckay, H. Yang, H. Zhong, M. H. Tuszynski, and V. R. Edgerton
Performance of locomotion and foot grasping following a unilateral thoracic corticospinal tract lesion in monkeys (Macaca mulatta)
Brain, October 1, 2005; 128(10): 2338 - 2358.
[Abstract] [Full Text] [PDF]
M.-P. Cote and J.-P. Gossard
Step Training-Dependent Plasticity in Spinal Cutaneous Pathways
J. Neurosci., December 15, 2004; 24(50): 11317 - 11327.
[Abstract] [Full Text] [PDF]
S. Rossignol and L. Bouyer
Adaptive Mechanisms of Spinal Locomotion in Cats
Integr. Comp. Biol., February 1, 2004; 44(1): 71 - 79.
[Abstract] [Full Text] [PDF]
|
|
|
|
 |
|