Stimulation of the Parapyramidal Region of the Neonatal Rat Brain Stem Produces Locomotor-Like Activity Involving Spinal 5-HT<sub>7</sub> and 5-HT<sub>2A</sub> Receptors

Li, Jun; Jordan, Larry M.

doi:10.1152/jn.00136.2005

Cited by 152 publications

(184 citation statements)

References 76 publications

Supporting

Mentioning

164

Contrasting

Order By: Relevance

“…Stimulation of the mesencephalic locomotor region can clearly change the state dependence of the spinal cord, e.g., change its responsiveness to sensory input. Although the brainstem can be stimulated at an intensity that does not generate locomotor movements until the limbs are placed on a moving belt, there is evidence that brainstem simulation can induce a stepping pattern in the limbs even in the absence of a moving treadmill belt (Liu and Jordan, 2005). There is little evidence, however, that such stepping-like motions are completely independent and fully weight bearing in response to stimulation of the mesencephalic locomotor region.…”

Section: Modulation Of the Physiological State And Afferent Control Omentioning

confidence: 99%

Training locomotor networks

Edgerton

Courtine

Gerasimenko

et al. 2008

Brain Research Reviews

276

205

View full text Add to dashboard Cite

For a complete adult spinal rat to regain some weight-bearing stepping capability, it appears that a sequence of specific proprioceptive inputs that are similar, but not identical, from step to step must be generated over repetitive step cycles. Furthermore, these cycles must include the activation of specific neural circuits that are intrinsic to the lumbosacral spinal cord segments. For these sensorimotor pathways to be effective in generating stepping, the spinal circuitry must be modulated to an appropriate excitability level. This level of modulation is sustained from supraspinal input in intact, but not spinal, rats. In a series of experiments with complete spinal rats, we have shown that an appropriate level of excitability of the spinal circuitry can be achieved using widely different means. For example, this modulation level can be acquired pharmacologically, via epidural electrical stimulation over specific lumbosacral spinal cord segments, and/or by use-dependent mechanisms such as step or stand training. Evidence as to how each of these treatments can "tune" the spinal circuitry to a "physiological state" that enables it to respond appropriately to proprioceptive input will be presented. We have found that each of these interventions can enable the proprioceptive input to actually control extensive details that define the dynamics of stepping over a range of speeds, loads, and directions. A series of experiments will be described that illustrate sensory control of stepping and standing after a spinal cord injury and the necessity for the "physiological state" of the spinal circuitry to be modulated within a critical window of excitability for this control to be manifested. The present findings have important consequences not only for our understanding of how the motor pattern for stepping is formed, but also for the design of rehabilitation intervention to restore lumbosacral circuit function in humans following a spinal cord injury.

show abstract

Section: Modulation Of the Physiological State And Afferent Control Omentioning

confidence: 99%

Training locomotor networks

Edgerton

Courtine

Gerasimenko

et al. 2008

Brain Research Reviews

276

205

View full text Add to dashboard Cite

show abstract

“…They are in the ventromedial spinal cord (Kjaerulff and Kiehn, 1996); c. They receive glutamatergic reticulospinal (Douglas et al, 1993;Noga et al, 2003;Ohta and Grillner, 1989) and descending serotonergic input (Liu and Jordan, 2005;MacLean et al, 1998;Ribotta et al, 2000);…”

Section: Amentioning

confidence: 99%

Strategies for delineating spinal locomotor rhythm-generating networks and the possible role of Hb9 interneurones in rhythmogenesis

Brownstone

Wilson

2008

Brain Research Reviews

136

122

View full text Add to dashboard Cite

Despite significant advances in our understanding of pattern generation in invertebrates and lower vertebrates, there have been barriers to the application of the principles learned to the definition of networks underlying mammalian locomotion. Major difficulties have arisen in identifying spinal interneurones in preparations which allow study of neuronal intrinsic properties and the role of identified interneurones in locomotor networks. Recent genetic technologies in which selective expression of fluorescent proteins in specific populations of mouse spinal neurones have provided new avenues of investigation. In this review, we focus on the generation of locomotor rhythm and outline criteria that rhythm-generating neurones might be expected to fulfill. We then examine the extent to which a recently identified population of spinal interneurones, Hb9 interneurones, fulfill these criteria. Finally, we suggest that Hb9 interneurones could be involved in an asymmetric model of locomotor rhythmogenesis through projections of electrotonically coupled rhythmgenerating modules to flexor pattern formation half-centres. The principles learned from studying this population of interneurones have led to strategies to systematically evaluate neurones that may be involved in locomotor rhythmogenesis.

show abstract

“…The preparation was then allowed to equilibrate for at least another 30 min. In some cases, we dissected out the brain stem and spinal cord, and similar procedures were followed except the transection was made at the exit point of cranial nerve VII (Liu and Jordan 2005).…”

Section: Introductionmentioning

confidence: 99%

Interaction Between Developing Spinal Locomotor Networks in the Neonatal Mouse

Gordon¹,

Dunbar²,

Vanneste³

et al. 2008

Journal of Neurophysiology

View full text Add to dashboard Cite

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.

show abstract

Stimulation of the Parapyramidal Region of the Neonatal Rat Brain Stem Produces Locomotor-Like Activity Involving Spinal 5-HT₇ and 5-HT_2A Receptors

Cited by 152 publications

References 76 publications

Training locomotor networks

Training locomotor networks

Strategies for delineating spinal locomotor rhythm-generating networks and the possible role of Hb9 interneurones in rhythmogenesis

Interaction Between Developing Spinal Locomotor Networks in the Neonatal Mouse

Contact Info

Product

Resources

About

Stimulation of the Parapyramidal Region of the Neonatal Rat Brain Stem Produces Locomotor-Like Activity Involving Spinal 5-HT7 and 5-HT2A Receptors

Cited by 152 publications

References 76 publications

Training locomotor networks

Training locomotor networks

Strategies for delineating spinal locomotor rhythm-generating networks and the possible role of Hb9 interneurones in rhythmogenesis

Interaction Between Developing Spinal Locomotor Networks in the Neonatal Mouse

Contact Info

Product

Resources

About

Stimulation of the Parapyramidal Region of the Neonatal Rat Brain Stem Produces Locomotor-Like Activity Involving Spinal 5-HT₇ and 5-HT_2A Receptors