Pharmacological aids to locomotor training after spinal injury in the cat

Rossignol, Serge; Giroux, Nicole; Chau, Connie; Marcoux, Judith; Brustein, Edna; Reader, Tomás A.

doi:10.1111/j.1469-7793.2001.0065b.x

Cited by 106 publications

(91 citation statements)

References 61 publications

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“…If so, attempts to substitute this supraspinal drive in spinal subjects by pharmacological or electrical stimulation of the cord below the lesion seem plausible. These methods appeared efficient for restoration of locomotor function in spinal animals (e.g., Gerasimenko et al 2008;Musienko et al 2007;Rossignol et al 1998Rossignol et al , 2001.…”

Section: Spinal Versus Supraspinal Origin Of Postural Responsesmentioning

confidence: 99%

Impairment of Postural Control in Rabbits With Extensive Spinal Lesions

Lyalka

Orlovsky²,

Deliagina³

2009

Journal of Neurophysiology

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. Our previous studies on rabbits demonstrated that the ventral spinal pathways are of primary importance for postural control in the hindquarters. After ventral hemisection, postural control did not recover, whereas after dorsal or lateral hemisection it did. The aim of this study was to examine postural capacity of rabbits after more extensive lesion (3/4 section of the spinal cord at T 12 level), that is, with only one ventral quadrant spared (VQ animals). They were tested before (control) and after lesion on the platform periodically tilted in the frontal plane. In control animals, tilts of the platform regularly elicited coordinated electromyographic (EMG) responses in the hindlimbs, which resulted in generation of postural corrections and in maintenance of balance. In VQ rabbits, the EMG responses appeared only in a part of tilt cycles, and they could be either correctly or incorrectly phased in relation to tilts. Because of a reduced value and incorrect phasing of EMG responses on both sides, this muscle activity did not cause postural corrective movements in the majority of rabbits, and the body swayed together with the platform. In these rabbits, the ability to perform postural corrections did not recover during the whole period of observation (Յ30 days). Low probability of correct EMG responses to tilts in most rabbits as well as an appearance of incorrect responses to tilts suggest that the spinal reflex chains, necessary for postural control, have not been specifically selected by a reduced supraspinal drive transmitted via a single ventral quadrant. I N T R O D U C T I O NMaintenance of the basic body posture, upright in humans and dorsal-side-up in quadrupeds, and keeping balance is a fundamental motor function. This nonvolitional form of motor activity in many species is based on inborn neural mechanisms (Deliagina et al. 2006;Massion 1998). An efficient control of the basic posture is equally important for standing and during walking (Horak and Macpherson 1996;Macpherson et al. 1997;Orlovsky et al. 1999) as well as for providing support of voluntary limb movements (Massion and Dufosse 1988).Damage to the spinal communication system (descending and ascending spinal pathways), caused by, e.g., a spinal cord injury (SCI), can result in an impairment of the postural control. This affects equilibrium both during standing and during locomotion and can impair voluntary movements that need postural support (Horak and Macpherson 1996). Apparently, postural deficits depend on the location and extent of SCI. A complete lesion of the spinal cord in the thoracic region separates the spinal postural mechanisms of the hindquarters from the rest of the CNS. This has dramatic consequences. Studies on chronic spinal cats have shown that they exhibit very poor responses to disturbances of posture and are not able to maintain the dorsal-side-up orientation of the caudal part of their body (Barbeau et al. 2002;Macpherson and Fung 1999;Rossignol et al. 1999Rossignol et al. , 2002. However, a reduced postural control (...

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Section: Spinal Versus Supraspinal Origin Of Postural Responsesmentioning

confidence: 99%

Impairment of Postural Control in Rabbits With Extensive Spinal Lesions

Lyalka

Orlovsky²,

Deliagina³

2009

Journal of Neurophysiology

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“…This approach was successfully used for activation of the hindlimb locomotor CPGs (Rossignol et al 1998(Rossignol et al , 2001. It was also shown that the two approaches (electrical and pharmacological stimulation) could be combined to enable well-coordinated stepping (Courtine et al 2009;Gerasimenko et al 2007).…”

Section: Introductionmentioning

confidence: 99%

Facilitation of Postural Limb Reflexes With Epidural Stimulation in Spinal Rabbits

Musienko

Zelenin

Orlovsky

et al. 2010

Journal of Neurophysiology

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Musienko PE, Zelenin PV, Orlovsky GN, Deliagina TG. Facilitation of postural limb reflexes with epidural stimulation in spinal rabbits. J Neurophysiol 103: 1080 -1092, 2010. First published December 16, 2009 doi:10.1152/jn.00575.2009. It is known that after spinalization animals lose their ability to maintain lateral stability when standing or walking. A likely reason for this is a reduction of the postural limb reflexes (PLRs) driven by stretch and load receptors of the limbs. The aim of this study was to clarify whether spinal networks contribute to the generation of PLRs. For this purpose, first, PLRs were recorded in decerebrated rabbits before and after spinalization at T12. Second, the effects of epidural electrical stimulation (EES) at L7 on the limb reflexes were studied after spinalization. To evoke PLRs, the vertebrate column of the rabbit was fixed, whereas the hindlimbs were positioned on the platform. Periodic lateral tilts of the platform caused antiphase flexion-extension limbs movements, similar to those observed in intact animals keeping balance on the tilting platform. Before spinalization, these movements evoked PLRs: augmentation of extensor EMGs and increase of contact force during limb flexion, suggesting their stabilizing postural effects. Spinalization resulted in almost complete disappearance of PLRs. After EES, however, the PLRs reappeared and persisted for up to several minutes, although their values were reduced. The post-EES effects could be magnified by intrathecal application of quipazine (5-HT agonist) at L4 -L6. Results of this study suggest that the spinal cord contains the neuronal networks underlying PLRs; they can contribute to the maintenance of lateral stability in intact subjects. In acute spinal animals, these networks can be activated by EES, suggesting that they are normally activated by a tonic supraspinal drive.

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“…1,2 In fact, even without pharmacological aids, regular TT assisted with a weight-supporting harness and/or tail or sexual organ pinching can enable the expression of involuntary 'reflex' stepping in low-thoracically spinal cord-transected (Tx) animals. [3][4][5] However, without assisted training, some spontaneously occurring small amplitude hindlimb movements were also shown to progressively occur a few weeks post-Tx in untrained Tx mice, [6][7][8] suggesting that basic spontaneous sublesional plasticity and spinal learning events may occur even in the absence of assisted training.…”

Section: Introductionmentioning

confidence: 99%

Non-assisted treadmill training does not improve motor recovery and body composition in spinal cord-transected mice

et al. 2010

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Study design: Experiments in a mouse model of complete paraplegia. Objectives: To evaluate the effect of non-assisted treadmill training on motor recovery and body composition in completely spinal cord-transected mice. Settings: Laval University Medical Center, Neuroscience Unit, Quebec City, Quebec, Canada. Methods: Following a complete low-thoracic (Th9/10) spinal transection (Tx), mice were divided into two groups that were either untrained or trained with no assistance. Training consisted of placing the mice during 15 min with no further intervention (that is no tail pinching or body weight support) on a motorized treadmill (8-10 cm s À1 ) five times per week for 5 weeks. Locomotor performances were assessed weekly in both groups using two complementary locomotor rating scales. After 5 weeks, all mice were killed and adipose tissue, soleus, and extensor digitorum longus muscles were dissected for analyses. Results: No significant difference in locomotor performances or in muscle fibre type conversion was found between trained and untrained mice. In contrast, body weight, adipose tissue, whole muscle, and individual fibre cross-sectional area (CSA) values were significantly lower in trained compared with untrained animals. Conclusions: Non-assisted treadmill training in these conditions did not improve motor performances and contributed to further accentuate body composition changes post-Tx, suggesting that assistance provided manually, robotically, or pharmacologically may be key to spinal learning and recovery of locomotor function and body composition.

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Pharmacological aids to locomotor training after spinal injury in the cat

Cited by 106 publications

References 61 publications

Impairment of Postural Control in Rabbits With Extensive Spinal Lesions

Impairment of Postural Control in Rabbits With Extensive Spinal Lesions

Facilitation of Postural Limb Reflexes With Epidural Stimulation in Spinal Rabbits

Non-assisted treadmill training does not improve motor recovery and body composition in spinal cord-transected mice

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