Crossed disynaptic inhibition of sacral motoneurones.

Jankowska, E.; Padel, Y; Zarzecki, P.

doi:10.1113/jphysiol.1978.sp012580

Cited by 70 publications

(37 citation statements)

References 32 publications

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“…This procedure was followed in view of the considerable differences in the location of spinal neurones and in the level of entry of afferent fibres in relation to the spinal segments in pre-and postfixed spinal cords (see Romanes, 1951). The compact column of small neurones, with prominent Nissl bodies, which form the pudendal nucleus was clearly seen at the lateral border of the ventral horn, half-way between the dorsally located lateral and medial popliteal motor nuclei and ventrally located tail and levator ani motoneurones (see Rexed, 1954, Figs 26 and 43;Romanes, 1951;Sato et al 1978;Jankowska, Padel & Zarzecki, 1978;Mackel, 1979). In the present study the rostral border of Onuf's nucleus was defined as the most rostral section containing the small neurones of the pudendal motor column without the much larger neurones which appeared in between them in more rostral sections.…”

Section: Histological Controlmentioning

confidence: 99%

A relay for input from group II muscle afferents in sacral segments of the cat spinal cord.

Jankowska

Riddell

1993

The Journal of Physiology

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SUMMARY1. A neuronal relay for input from group II afferents of hindlimb muscle nerves has been found in the previously little explored sacral segments of the cat spinal cord.2. Electrical stimulation of group II muscle afferents of a number of nerves evoked negative potentials on the surface (cord dorsum potentials) and population postsynaptic potentials (field potentials) within the sacral segments. The largest potentials were evoked by stimulation of the posterior biceps-semitendinosus and triceps surae nerves which evoke much smaller potentials in other segments. Group II afferents of other nerves, notably those which have their main relay within the middle lumbar segments, were much less effective.3. The sites at which cord dorsum and field potentials evoked by group II muscle afferents were recorded varied in relation to the external topography of the L7-S2 spinal segments but were consistent in their location relative to the pudendal motor nucleus (Onuf's nucleus). Potentials evoked by group II afferents of the posterior biceps and semitendinosus nerves peaked at a level corresponding to the rostral half of Onuf's nucleus and potentials evoked by afferents of the gastrocnemius nerves peaked just rostral to this nucleus. The largest field potentials (of 05-lO mV) were recorded within the dorsal horn. Field potentials in the intermediate zone were much smaller ( < 0 3 mV) and were seen less frequently.4. Evidence was obtained that the dorsal horn field potentials are to a great extent evoked monosynaptically by the fast conducting fraction of group II muscle afferents: (i) they were evoked at short latencies (2A4-2-7 ms from the stimulus; 1P3-1H7 ms from group I components of afferent volleys and 05-07 ms from group II components of these volleys), (ii) the conduction times of impulses in the fastest conducting fraction of group II afferents, between the sacral segments (where these impulses were induced by intraspinal stimuli) and the peripheral nerves, were only about 0 5 ms shorter than the latencies of field potentials recorded at the site of intraspinal stimulation and evoked by stimulation of the same peripheral nerves and, (iii) the field potentials followed repetitive stimuli without temporal facilitation. * Present address: Institute of Physiology, University of Glasgow, Glasgow G12 8QQ, Scotland.MS 1701 E. JANKOWSKA AND J. S. RIDDELL 5. Negative cord dorsum and field potentials were also evoked by small stretches of the semitendinosus and triceps surae muscles. Although they were smaller than potentials evoked by electrical stimulation of sensory fibres and appeared at longer latencies, their presence is consistent with a contribution of muscle spindle afferents to the actions of group II muscle afferents within the sacral segments.6. The study leads to the conclusion that there are neurones within the sacral segments that mediate the actions of group II afferents primarily of posterior biceps and semitendinosus and gastrocnemius-soleus. Together with previous observations on the actions of group ...

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Section: Histological Controlmentioning

confidence: 99%

A relay for input from group II muscle afferents in sacral segments of the cat spinal cord.

Jankowska

Riddell

1993

The Journal of Physiology

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“…In another study, inhibitory postsynaptic potentials mediated by a disynaptic pathway were recorded in motoneurons of the sacral cord following stimulation of low-threshold fibers of the contralateral dorsal root of the same segment (Curtis et al 1958). Crossed disynaptic inhibition of sacral motoneurons was shown to be mediated by group Ia muscle spindle afferents (Jankowska et al 1978). Stimulation of group II or cutaneous afferents in nonlocomotor anesthetized cats also evokes short-latency inhibition in contralateral ankle extensor motoneurons (Aggelopoulos et al 1996;Arya et al 1991;Edgley and Aggelopoulos 2006).…”

Section: Introductionmentioning

confidence: 99%

Short-Latency Crossed Inhibitory Responses in Extensor Muscles During Locomotion in the Cat

Frigon

Rossignol²

2008

Journal of Neurophysiology

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During locomotion, contacting an obstacle generates a coordinated response involving flexion of the stimulated leg and activation of extensors contralaterally to ensure adequate support and forward progression. Activation of motoneurons innervating contralateral muscles (i.e., crossed extensor reflex) has always been described as an excitation, but the present paper shows that excitatory responses during locomotion are almost always preceded by a short period of inhibition. Data from seven cats chronically implanted with bipolar electrodes to record electromyography (EMG) of several hindlimb muscles bilaterally were used. A stimulating cuff electrode placed around the left tibial and left superficial peroneal nerves at the level of the ankle in five and two cats, respectively, evoked cutaneous reflexes during locomotion. During locomotion, short-latency (ϳ13 ms) inhibitory responses were frequently observed in extensors of the right leg (i.e., contralateral to the stimulation), such as gluteus medius and triceps surae muscles, which were followed by excitatory responses (ϳ25 ms). Burst durations of the left sartorius (Srt), a hip flexor, and ankle extensors of the right leg increased concomitantly in the mid-to late-flexion phases of locomotion with nerve stimulation. Moreover, the onset and offset of Srt and ankle extensor bursts bilaterally were altered in specific phases of the step cycle. Short-latency crossed inhibition in ankle extensors appears to be an integral component of cutaneous reflex pathways in intact cats during locomotion, which could be important in synchronizing EMG bursts in muscles of both legs.

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“…At a segmental level, movements performed with one limb typically result in depression of the central gain of the Ia afferent reflex pathway (4,6,14). There are also crossed interactions between inhibitory interneurons that receive inputs from primary muscle afferents (8,16, 34).Because high-force contractions promote strong interhemispheric interactions, the spillover hypothesis fits well as a possible explanation for the bilateral improvements in muscular strength that can occur in response to unilateral exercise involving high-force contractions (i.e., strength training). This contralateral strength training effect is a form of cross-transfer that has been known since 1894 (36).…”

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Unilateral practice of a ballistic movement causes bilateral increases in performance and corticospinal excitability

Carroll

Lee

Hsu

et al. 2008

Journal of Applied Physiology

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Carroll TJ, Lee M, Hsu M, Sayde J. Unilateral practice of a ballistic movement causes bilateral increases in performance and corticospinal excitability. J Appl Physiol 104: 1656-1664. First published April 10, 2008 doi:10.1152/japplphysiol.01351.2007.-It has long been known that practicing a task with one limb can result in performance improvements with the opposite, untrained limb. Hypotheses to account for cross-limb transfer of performance state that the effect is mediated either by neural adaptations in higher order control centers that are accessible to both limbs, or that there is a "spillover" of neural drive to the opposite hemisphere that results in bilateral adaptation. Here we address these hypotheses by assessing performance and corticospinal excitability in both hands after unilateral practice of a ballistic finger movement. Participants (n ϭ 9) completed 300 practice trials of a ballistic task with the right hand, the aim of which was to maximize the peak abduction acceleration of the index finger. Practice caused a 140% improvement in right-hand performance and an 82% improvement for the untrained left hand. There were bilateral increases in the amplitude of responses to transcranial magnetic stimulation, but increased corticospinal excitability was not correlated with improved performance. There were no significant changes in corticospinal excitability or task performance for a control group that did not train (n ϭ 9), indicating that performance testing for the left hand alone did not induce performance or corticospinal effects. Although the data do not provide conclusive evidence whether increased corticospinal excitability in the untrained hand is causally related to the cross-transfer of ballistic performance, the finding that ballistic practice can induce bilateral corticospinal adaptations may have important clinical implications for movement rehabilitation. motor control; training; transcranial magnetic stimulation; human; motor cortex THERE IS AN EXTENSIVE LITERATURE, stemming from the mid 19th century, that unilateral motor practice can result in bilateral performance improvements (see Refs. 1, 2, 36). This effect has been variously termed "cross-transfer," "cross-education," and "interlimb transfer," and it has been demonstrated for a wide range of motor tasks including mirror tracing, movement tasks under visuomotor rotations and novel force field conditions, execution of multifinger tapping sequences, exertion of maximal force, and tasks requiring fine control of movement timing and force (e.g., Refs. 3,11,32,33,41,43,44). Most theoretical attempts to account for cross-transfer are based on the idea that the neural adaptations underlying improved performance with the trained limb must reside at a central nervous system (CNS) site that is also accessible for the control of the contralateral limb (e.g., Refs. 15, 21, 42). Here we test an alternative hypothesis, proposed by Parlow and Kinsbourne (30), that certain types of cross-transfer occur because practice induces bilateral neural a...

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Crossed disynaptic inhibition of sacral motoneurones.

Cited by 70 publications

References 32 publications

A relay for input from group II muscle afferents in sacral segments of the cat spinal cord.

A relay for input from group II muscle afferents in sacral segments of the cat spinal cord.

Short-Latency Crossed Inhibitory Responses in Extensor Muscles During Locomotion in the Cat

Unilateral practice of a ballistic movement causes bilateral increases in performance and corticospinal excitability

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