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Propriospinal Circuitry and Gait

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    Propriospinal Circuitry and Gait

    Another interesting article pointing out that quadruped and biped neural circuitry controlling locomotor rythmicity (CPGs) extends from the lumbar region through the cervical levels. I would think that this has numerous clinical implications concerning the restoration of gait.

    J Neurosci. 2005 Jun 22;25(25):6025-35.

    Propriospinal circuitry underlying interlimb coordination in mammalian quadrupedal locomotion.

    Juvin L, Simmers J, Morin D.

    Laboratoire de Physiologie et Physiopathologie de la Signalisation Cellulaire, Centre National de la Recherche Scientifique, Unite Mixte de Recherche 5543, Equipe Neurophysiologie Adaptative des Systemes Moteurs, 33076 Bordeaux, France.

    Soon after birth, freely moving quadrupeds can express locomotor activity with coordinated forelimb and hindlimb movements. To investigate the neural mechanisms underlying this coordination, we used an isolated spinal cord preparation from neonatal rats. Under bath-applied 5-HT, N-methyl-d,l-aspartate (NMA), and dopamine (DA), the isolated cord generates fictive locomotion in which homolateral cervicolumbar extensor motor bursts occur in phase opposition, as does bursting in homologous (left-right) extensor motoneurons. This coordination corresponded to a walking gait monitored with EMG recordings in the freely behaving animal. Functional decoupling of the cervical and lumbar generators in vitro by sucrose blockade at the thoracic cord level revealed independent rhythmogenic capabilities with similar cycle frequencies in the two locomotor regions. When the cord was partitioned at different thoracic levels and 5-HT/NMA/DA was applied to the more caudal compartment, the ability of the lumbar generators to drive their cervical counterparts increased with the proportion of chemically exposed thoracic segments. Blockade of synaptic inhibition at the lumbar level caused synchronous bilateral lumbar rhythmicity that, surprisingly, also was able to impose bilaterally synchronous bursting at the unblocked cervical level. Furthermore, after a midsagittal section from spinal segments C1 to T7, and during additional blockade of cervical synaptic inhibition, the cord exposed to 5-HT/NMA/DA continued to produce a coordinated fictive walking pattern similar to that observed in control. Thus, in the newborn rat, a caudorostral propriospinal excitability gradient appears to mediate interlimb coordination, which relies more on asymmetric axial connectivity (both excitatory and inhibitory) between the lumbar and cervical generators than on differences in their inherent rhythmogenic capacities.
    “As the cast of villains in SCI is vast and collaborative, so too must be the chorus of hero's that rise to meet them” Ramer et al 2005

    Here is an old one...

    Trends Neurosci. 2002 Sep;25(9):462-7. Related Articles, Links

    Do human bipeds use quadrupedal coordination?

    Dietz V.

    ParaCare, Institute for Rehabilitation and Research, University Hospital Balgrist, Forchstrasse 340, 8008 Zurich, Switzerland.

    Tackling the question of whether control of human gait is based on that of a quadrupedal locomotion system is of basic and practical relevance. During evolution, the increased influence of a direct cortical-motoneuronal system in parallel with more specialized hand function might have replaced phylogenetically older systems that organized locomotor movements. However, recent research indicates that interlimb coordination during human locomotion is organized in a similar way to that in the cat. Hence, it is hypothesized that during locomotion, corticospinal excitation of upper limb motoneurons is mediated indirectly, via propriospinal neurons in the cervical spinal cord. This allows a task-dependent neuronal linkage of cervical and thoraco-lumbar propriospinal circuits controlling leg and arm movements during human locomotor activities. The persistence of such movement control has consequences for rehabilitation and the applicability of animal research to human patients with spinal cord injury.

    Publication Types:
    Review, Tutorial

    PMID: 12183207 [PubMed - indexed for MEDLINE]

    Eric Harness, CSCS
    Neuro Ex, Inc
    Adaptive Performance and Neuro Recovery


      Definetly a good article. I would suggest reading most publications by Dietz, they are a good source of information concerning rehab and locomotion
      “As the cast of villains in SCI is vast and collaborative, so too must be the chorus of hero's that rise to meet them” Ramer et al 2005