Forelimb locomotor generators and quadrupedal locomotion in the neonatal rat

Ballion, Bérangère; Morin, Didier; Viala, D.

doi:10.1046/j.0953-816x.2001.01794.x

Cited by 125 publications

(125 citation statements)

References 55 publications

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“…This cervical pattern was similar to that reported in the neonatal rat preparation using bath application of drugs (Ballion et al 2001;Juvin et al 2005). Ipsilaterally, the C 5 bursts alternated with the C 8 's and segmentally both the C 5 and C 8 roots alternated with each other.…”

Section: Rhythmogenic Capability Of Cervicothoracic Regionssupporting

confidence: 67%

“…Our brain stem stimulation experiments showed that when the lumbar CPG was activated, it led to longer stable periods of cervical rhyth- micity. Electrical and or pharmacological activation of thoracosacral networks produced a clear signature of locomotor-like activity (Whelan et al 2000) but did not elicit distinct ipsilateral C 5 -C 8 alternating activity as observed in neonatal rats (Ballion et al 2001). Instead the patterns evoked rostrally have an increasing delayed onset when compared with the L 2 bursts.…”

Section: Interactions Between Cervical and Lumbar Pattern Generatorsmentioning

confidence: 94%

“…Nevertheless, one would expect that the cervical regions would be further advanced if network development progresses in a rostrocaudal fashion. Although the neonatal rat shows activation of alternating cervical and lumbar patterns following drug application, (Ballion et al 2001;Juvin et al 2007), there is no a priori reason to suspect that monoaminergic receptor distributions are similar in both species. For example while rats appear to require thoracic segments to generate 5-HT-dependent rhythmic patterns in lumbar segments (Cowley and Schmidt 1997), the mouse at similar gestation ages does not (Nishimaru and Kudo 2000).…”

Section: Rhythmogenic Capability Of Cervicothoracic Regionsmentioning

confidence: 99%

“…Such activity would be expected to consist of alternating flexor-extensor activity that can be resolved by recording alternating bursts from C 5 and C 8 segments (Figs. 1 and 2) (Ballion et al 2001;McKenna et al 2000). To test the hypothesis that cervical segments were producing locomotor-like activity, we evoked locomotor-like rhythms via cauda equina stimulation as previously described and recorded from the ipsilateral C 5 , C 8 , T 10 , L 2 , and L 5 ventral roots (Fig.…”

Section: Cauda Equina Activation Of Thoracocervical Segments Does Notmentioning

confidence: 99%

“…The cervical and lumbar CPGs rely on propriospinal connectivity to remain appropriately coordinated (Grillner 1981). Previous studies investigating cervicolumbar interactions have revealed an excitatory drive from the lumbar to the cervical network in the adult cat (Akay et al 2006) and neonatal rat (Ballion et al 2001;Juvin et al 2005). Additionally, the importance of cervical to lumbar propriospinal projections in the bulbospinal activation of the locomotor network of the neonatal rat has recently been revealed (Zaporozhets et al 2006).…”

Section: Introductionmentioning

confidence: 99%

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Interaction Between Developing Spinal Locomotor Networks in the Neonatal Mouse

Gordon¹,

Dunbar²,

Vanneste³

et al. 2008

Journal of Neurophysiology

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Gordon IT, Dunbar MJ, Vanneste KJ, Whelan PJ. Interaction between developing spinal locomotor networks in the neonatal mouse. J Neurophysiol 100: 117-128, 2008. First published April 24, 2008 doi:10.1152/jn.00829.2007. At birth, thoracosacral spinal cord networks in mouse can produce a coordinated locomotor-like pattern. In contrast, less is known about the cervicothoracic networks that generate forelimb locomotion. Here we show that cervical networks can produce coordinated rhythmic patterns in the brain stem-spinal cord preparation of the mouse. Segmentally the C 5 and C 8 neurograms were each found to be alternating left-right, and the ipsilateral C 5 and C 8 neurograms also alternated. Collectively these patterns were suggestive of locomotor-like activity. This pattern was not dependent on the presence of thoracosacral segments because they could be evoked following a complete transection of the spinal cord at T 5 . We next demonstrated that activation of thoracosacral networks either pharmacologically or by stimulation of sacrocaudal afferents could produce rhythmic activity within the C 5 and C 8 neurograms. On the other hand, pharmacological activation of cervical networks did not evoke alternating cervical rhythmic activity either in isolated cervicothoracic or -sacral preparations. Under these conditions, we found that activation of cervicothoracic networks could alter the timing of thoracosacral locomotor-like patterns. When thoracosacral networks were not activated pharmacologically but received rhythmic drive from cervicothoracic networks, a pattern of slow bursts with superimposed fast synchronous oscillations became the dominant lumbar neurogram pattern. Our data suggest that in neonatal mice the cervical CPG is capable of producing coordinated rhythmic patterns in the absence of input from lumbar segments, but caudorostral drive contributes to cervical patterns and rhythm stability.

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Section: Rhythmogenic Capability Of Cervicothoracic Regionssupporting

confidence: 67%

Section: Interactions Between Cervical and Lumbar Pattern Generatorsmentioning

confidence: 94%

Section: Rhythmogenic Capability Of Cervicothoracic Regionsmentioning

confidence: 99%

Section: Cauda Equina Activation Of Thoracocervical Segments Does Notmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Interaction Between Developing Spinal Locomotor Networks in the Neonatal Mouse

Gordon¹,

Dunbar²,

Vanneste³

et al. 2008

Journal of Neurophysiology

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Control of Breathing During Exercise

Forster

Haouzi

Dempsey

2012

Comprehensive Physiology

198

203

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During exercise by healthy mammals, alveolar ventilation and alveolar-capillary diffusion increase in proportion to the increase in metabolic rate to prevent PaCO2 from increasing and PaO2 from decreasing. There is no known mechanism capable of directly sensing the rate of gas exchange in the muscles or the lungs; thus, for over a century there has been intense interest in elucidating how respiratory neurons adjust their output to variables which can not be directly monitored. Several hypotheses have been tested and supportive data were obtained, but for each hypothesis, there are contradictory data or reasons to question the validity of each hypothesis. Herein, we report a critique of the major hypotheses which has led to the following conclusions. First, a single stimulus or combination of stimuli that convincingly and entirely explains the hyperpnea has not been identified. Second, the coupling of the hyperpnea to metabolic rate is not causal but is due to of these variables each resulting from a common factor which link the circulatory and ventilatory responses to exercise. Third, stimuli postulated to act at pulmonary or cardiac receptors or carotid and intracranial chemoreceptors are not primary mediators of the hyperpnea. Fourth, stimuli originating in exercising limbs and conveyed to the brain by spinal afferents contribute to the exercise hyperpnea. Fifth, the hyperventilation during heavy exercise is not primarily due to lactacidosis stimulation of carotid chemoreceptors. Finally, since volitional exercise requires activation of the CNS, neural feed-forward (central command) mediation of the exercise hyperpnea seems intuitive and is supported by data from several studies. However, there is no compelling evidence to accept this concept as an indisputable fact.

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Locomotor recovery after spinal cord hemisection/contusion injures in bonnet monkeys: Footprint testing—a minireview

Rangasamy

2013

Synapse

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Spinal cord injuries usually produce loss or impairment of sensory, motor and reflex function below the level of damage. In the absence of functional regeneration or manipulations that promote regeneration, spontaneous improvements in motor functions occur due to the activation of multiple compensatory mechanisms in animals and humans following the partial spinal cord injury. Many studies were performed on quantitative evaluation of locomotor recovery after induced spinal cord injury in animals using behavioral tests and scoring techniques. Although few studies on rodents have led to clinical trials, it would appear imperative to use nonhuman primates such as macaque monkeys in order to relate the research outcomes to recovery of functions in humans. In this review, we will discuss some of our research evidences concerning the degree of spontaneous recovery in bipedal locomotor functions of bonnet monkeys that underwent spinal cord hemisection/contusion lesions. To our knowledge, this is the first report to discuss on the extent of spontaneous recovery in bipedal locomotion of macaque monkeys through the application of footprint analyzing technique. In addition, the results obtained were compared with the published data on recovery of quadrupedal locomotion of spinally injured rodents. We propose that the mechanisms underlying spontaneous recovery of functions in spinal cord lesioned monkeys may be correlated to the mature function of spinal pattern generator for locomotion under the impact of residual descending and afferent connections. Moreover, based on analysis of motor functions observed in locomotion in these subjected monkeys, we understand that spinal automatism and development of responses by afferent stimuli from outside the cord could possibly contribute to recovery of paralyzed hindlimbs. This report also emphasizes the functional contribution of progressive strengthening of undamaged nerve fibers through a collateral sprouts/synaptic plasticity formed in partially lesioned cord of monkeys.

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Forelimb locomotor generators and quadrupedal locomotion in the neonatal rat

Cited by 125 publications

References 55 publications

Interaction Between Developing Spinal Locomotor Networks in the Neonatal Mouse

Interaction Between Developing Spinal Locomotor Networks in the Neonatal Mouse

Control of Breathing During Exercise

Locomotor recovery after spinal cord hemisection/contusion injures in bonnet monkeys: Footprint testing—a minireview

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