Organization of common synaptic drive to motoneurones during fictive locomotion in the spinal cat

J.B. Nielsen, B.A. Conway, D.M. Halliday, M.C. Perreault, H. Hultborn

    Research output: Contribution to journalArticle

    21 Citations (Scopus)

    Abstract

    The basic locomotor rhythm in the cat is generated by a neuronal network in the spinal cord. The exact organization of this network and its drive to the spinal motoneurones is unknown. The purpose of the present study was to use time (cumulant density) and frequency domain (coherence) analysis to examine the organization of the last order drive to motoneurones during fictive locomotion (evoked by application of nialamide and dihydroxyphenylalanine (DOPA)) in the spinal cat. In all cats, narrow central synchronization peaks (half-width < 3 ms) were observed in cumulants estimated between electroneurograms (ENGs) of close synergists, but not between nerves belonging to muscles acting on different joints or to antagonistic muscles. Coherence was not observed at frequencies above 100 Hz and was mainly observed between synergists. Intracellular recording was obtained from a population of 70 lumbar motoneurones. Significant short-term synchronization was observed between the individual intracellular recordings and the ENGs recorded from nerves of the same pool and of close synergists. Recordings from 34 pairs of motoneurones (10 pairs belonged to the same motor pool, 11 pairs to close synergists and 13 pairs to antagonistic pools) failed to reveal any short-lasting synchronization. These data demonstrate that short-term synchronization during fictive locomotion is relatively weak and is restricted to close synergists. In addition, coherence analysis failed to identify any specific rhythmic component in the locomotor drive that could be associated with this synchronization. These results resemble findings obtained during human treadmill walking and imply that the spinal interneurones participating in the generation of the locomotor rhythm are themselves weakly synchronized. The restricted synchronization within the locomotor drive to motoneuronal pools may be a feature of the locomotor generating networks that is related to the ability of these networks to produce highly adaptive patterns of muscle activity during locomotion.
    LanguageEnglish
    Pages291-304
    Number of pages13
    JournalJournal of Physiology
    Volume569
    Issue number1
    DOIs
    Publication statusPublished - 2005

    Fingerprint

    Motor Neurons
    Locomotion
    Cats
    Muscles
    Nialamide
    Dihydroxyphenylalanine
    Interneurons
    Walking
    Spinal Cord
    Joints
    Population

    Keywords

    • motoneurones
    • spinal cord
    • bioengineering
    • neurophysiology

    Cite this

    Nielsen, J.B. ; Conway, B.A. ; Halliday, D.M. ; Perreault, M.C. ; Hultborn, H. / Organization of common synaptic drive to motoneurones during fictive locomotion in the spinal cat. In: Journal of Physiology. 2005 ; Vol. 569, No. 1. pp. 291-304.
    @article{636b766dd34e405fb00541cabff2d521,
    title = "Organization of common synaptic drive to motoneurones during fictive locomotion in the spinal cat",
    abstract = "The basic locomotor rhythm in the cat is generated by a neuronal network in the spinal cord. The exact organization of this network and its drive to the spinal motoneurones is unknown. The purpose of the present study was to use time (cumulant density) and frequency domain (coherence) analysis to examine the organization of the last order drive to motoneurones during fictive locomotion (evoked by application of nialamide and dihydroxyphenylalanine (DOPA)) in the spinal cat. In all cats, narrow central synchronization peaks (half-width < 3 ms) were observed in cumulants estimated between electroneurograms (ENGs) of close synergists, but not between nerves belonging to muscles acting on different joints or to antagonistic muscles. Coherence was not observed at frequencies above 100 Hz and was mainly observed between synergists. Intracellular recording was obtained from a population of 70 lumbar motoneurones. Significant short-term synchronization was observed between the individual intracellular recordings and the ENGs recorded from nerves of the same pool and of close synergists. Recordings from 34 pairs of motoneurones (10 pairs belonged to the same motor pool, 11 pairs to close synergists and 13 pairs to antagonistic pools) failed to reveal any short-lasting synchronization. These data demonstrate that short-term synchronization during fictive locomotion is relatively weak and is restricted to close synergists. In addition, coherence analysis failed to identify any specific rhythmic component in the locomotor drive that could be associated with this synchronization. These results resemble findings obtained during human treadmill walking and imply that the spinal interneurones participating in the generation of the locomotor rhythm are themselves weakly synchronized. The restricted synchronization within the locomotor drive to motoneuronal pools may be a feature of the locomotor generating networks that is related to the ability of these networks to produce highly adaptive patterns of muscle activity during locomotion.",
    keywords = "motoneurones, spinal cord, bioengineering, neurophysiology",
    author = "J.B. Nielsen and B.A. Conway and D.M. Halliday and M.C. Perreault and H. Hultborn",
    year = "2005",
    doi = "10.1113/jphysiol.2005.091744",
    language = "English",
    volume = "569",
    pages = "291--304",
    journal = "Journal of Physiology",
    issn = "0022-3751",
    number = "1",

    }

    Organization of common synaptic drive to motoneurones during fictive locomotion in the spinal cat. / Nielsen, J.B.; Conway, B.A.; Halliday, D.M.; Perreault, M.C.; Hultborn, H.

    In: Journal of Physiology, Vol. 569, No. 1, 2005, p. 291-304.

    Research output: Contribution to journalArticle

    TY - JOUR

    T1 - Organization of common synaptic drive to motoneurones during fictive locomotion in the spinal cat

    AU - Nielsen, J.B.

    AU - Conway, B.A.

    AU - Halliday, D.M.

    AU - Perreault, M.C.

    AU - Hultborn, H.

    PY - 2005

    Y1 - 2005

    N2 - The basic locomotor rhythm in the cat is generated by a neuronal network in the spinal cord. The exact organization of this network and its drive to the spinal motoneurones is unknown. The purpose of the present study was to use time (cumulant density) and frequency domain (coherence) analysis to examine the organization of the last order drive to motoneurones during fictive locomotion (evoked by application of nialamide and dihydroxyphenylalanine (DOPA)) in the spinal cat. In all cats, narrow central synchronization peaks (half-width < 3 ms) were observed in cumulants estimated between electroneurograms (ENGs) of close synergists, but not between nerves belonging to muscles acting on different joints or to antagonistic muscles. Coherence was not observed at frequencies above 100 Hz and was mainly observed between synergists. Intracellular recording was obtained from a population of 70 lumbar motoneurones. Significant short-term synchronization was observed between the individual intracellular recordings and the ENGs recorded from nerves of the same pool and of close synergists. Recordings from 34 pairs of motoneurones (10 pairs belonged to the same motor pool, 11 pairs to close synergists and 13 pairs to antagonistic pools) failed to reveal any short-lasting synchronization. These data demonstrate that short-term synchronization during fictive locomotion is relatively weak and is restricted to close synergists. In addition, coherence analysis failed to identify any specific rhythmic component in the locomotor drive that could be associated with this synchronization. These results resemble findings obtained during human treadmill walking and imply that the spinal interneurones participating in the generation of the locomotor rhythm are themselves weakly synchronized. The restricted synchronization within the locomotor drive to motoneuronal pools may be a feature of the locomotor generating networks that is related to the ability of these networks to produce highly adaptive patterns of muscle activity during locomotion.

    AB - The basic locomotor rhythm in the cat is generated by a neuronal network in the spinal cord. The exact organization of this network and its drive to the spinal motoneurones is unknown. The purpose of the present study was to use time (cumulant density) and frequency domain (coherence) analysis to examine the organization of the last order drive to motoneurones during fictive locomotion (evoked by application of nialamide and dihydroxyphenylalanine (DOPA)) in the spinal cat. In all cats, narrow central synchronization peaks (half-width < 3 ms) were observed in cumulants estimated between electroneurograms (ENGs) of close synergists, but not between nerves belonging to muscles acting on different joints or to antagonistic muscles. Coherence was not observed at frequencies above 100 Hz and was mainly observed between synergists. Intracellular recording was obtained from a population of 70 lumbar motoneurones. Significant short-term synchronization was observed between the individual intracellular recordings and the ENGs recorded from nerves of the same pool and of close synergists. Recordings from 34 pairs of motoneurones (10 pairs belonged to the same motor pool, 11 pairs to close synergists and 13 pairs to antagonistic pools) failed to reveal any short-lasting synchronization. These data demonstrate that short-term synchronization during fictive locomotion is relatively weak and is restricted to close synergists. In addition, coherence analysis failed to identify any specific rhythmic component in the locomotor drive that could be associated with this synchronization. These results resemble findings obtained during human treadmill walking and imply that the spinal interneurones participating in the generation of the locomotor rhythm are themselves weakly synchronized. The restricted synchronization within the locomotor drive to motoneuronal pools may be a feature of the locomotor generating networks that is related to the ability of these networks to produce highly adaptive patterns of muscle activity during locomotion.

    KW - motoneurones

    KW - spinal cord

    KW - bioengineering

    KW - neurophysiology

    UR - http://dx.doi.org/10.1113/jphysiol.2005.091744

    U2 - 10.1113/jphysiol.2005.091744

    DO - 10.1113/jphysiol.2005.091744

    M3 - Article

    VL - 569

    SP - 291

    EP - 304

    JO - Journal of Physiology

    T2 - Journal of Physiology

    JF - Journal of Physiology

    SN - 0022-3751

    IS - 1

    ER -