Contralaterally projecting lamina VIII interneurones in middle lumbar segments in the cat

Jankowska, E.; Noga, Brian R.

doi:10.1016/0006-8993(90)91618-q

Cited by 80 publications

(60 citation statements)

References 11 publications

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“…Responses were classified as evoked monosynaptically when they were induced at latencies not exceeding 1 msec from the initial component of the descending volleys after RF stimuli. Whenever tested (in 12 neurons), stimuli applied at the thoracic level failed to induce antidromic activation of neurons projecting to the L7 contralateral motor nuclei, extending observations on Ͼ70 previously investigated L4 -L5 and L6 commissural neurons with input from muscle afferents (Harrison et al, 1986;Jankowska and Noga, 1990). The same thoracic (Th) stimuli (0.2 msec, 0.2-1 mA, applied by pairs of electrodes in contact with the left and right lateral funiculi) were effective in inducing antidromic activation of other, most likely spinocerebellar tract, neurons with group I input that were not antidromically activated from the motor nuclei in the same experiments.…”

Section: Methodssupporting

confidence: 73%

“…Activation of commissural neurons by reticulospinal neurons will be expected under all of the conditions when the reticulospinal tract neurons are activated, e.g., during locomotion induced by stimuli applied in the hook bundle of Russel or the cuneiform nuclei (Orlovsky, 1970;Shefchyk and Jordan, 1985;Jankowska and Noga, 1990;Mori et al, 1998). During locomotion in intact animals, reticulospinal neurons show phasic bursts (Drew et al, 1986).…”

Section: Indications For a Spinal Relay Of The Indirect Rf Synaptic Amentioning

confidence: 99%

“…Lamina VIII interneurons constitute the main group of neurons forming synaptic contacts with contralateral motoneurons (Scheibel and Scheibel, 1966;Harrison et al, 1986;Alstermark and Kummel, 1990;Hoover and Durkovic, 1992). Recently, some commissural neurons (including lamina VIII neurons) were found to be excited by stimuli applied in the pontomedullary reticular formation (RF), the mesencephalic and cerebellar locomotor regions from which reticulospinal neurons are activated (Jankowska and Noga, 1990;Matsuyama and Mori, 1998;Mori et al, 1998), or both. Neurons located in lamina VIII at some level in the lumbosacral enlargement have thus been considered very strong candidates for mediating any crossed disynaptic reticulospinal actions on motoneurons but are not the only candidates.…”

Section: Introductionmentioning

confidence: 99%

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Neuronal Basis of Crossed Actions from the Reticular Formation on Feline Hindlimb Motoneurons

et al. 2003

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Section: Methodssupporting

confidence: 73%

Section: Indications For a Spinal Relay Of The Indirect Rf Synaptic Amentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Neuronal Basis of Crossed Actions from the Reticular Formation on Feline Hindlimb Motoneurons

et al. 2003

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“…Jankowska & Zytnicki, 1986). Neurones which might mediate crossed group II actions are found in the midlumbar segments as short-propriospinal neurones which project to contralateral motor nuclei (Jankowska & Noga, 1990). If these neurones do have collateral projections to contralateral midlumbar neurones then this would imply a tight interlimb coupling since the crossed actions on midlumbar neurones would be collateral to direct actions on motoneurones.…”

Section: Discussionmentioning

confidence: 99%

Crossed actions on group II‐activated interneurones in the midlumbar segments of the cat spinal cord.

Bajwa¹,

Edgley²,

Harrison³

1992

The Journal of Physiology

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SUMMARY1. Evidence has been sought for crossed actions on midlumbar propriospinal neurones activated by ipsilateral group II muscle afferents, with particular emphasis on those neurones with projections to the ipsilateral hindlimb motor nuclei.2. A large majority of group II-activated midlumbar neurones were influenced by stimulation of contralateral group II afferents. The most frequent and most powerful actions were from those nerves which most effectively influenced ipsilateral midlumbar neurones. Crossed actions from group I afferents were rare.3. In the great majority of neurones the pattern of actions was similar from both limbs, the neurones being bilaterally excited, bilaterally inhibited or had both EPSPs and IPSPs from both sides.4. The latencies of crossed actions suggest that the earliest crossed EPSPs from group II afferents were evoked disynaptically (i.e. via a single commissural neurone) and that the crossed IPSPs were evoked trisynaptically.5. The pattern of crossed actions suggests a strong bilateral interaction between midlumbar neurones. The possible role of these neurones in postural control and the production of co-ordinated movements of the hindlimbs is discussed.

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“…For instance, single muscle spindle secondaries labelled by intra-axonal injection of horseradish peroxidase have been found to terminate within laminae IV-IX of the L6 and L7 segments (Fyffe, 1979;Hongo, Kudo, Yamashita, Ishizuka & Mannen, 1981;Ishizuka, Hongo, Kudo, Sasaki, Yamashita & Mannen, 1985;Hoheisel, LehmannWillenbrock & Mense, 1989;Hongo, 1992) and group II muscle afferent fibres have been activated by intraspinal stimuli applied at segmental levels from S1 to Thl3 (Eccles, Schmidt & Willis, 1963;Carpenter, Lundberg & Norrsell, 1963;Fern, Harrison & Riddell, 1988;Jimenez, Rudomin & Solodkin, 1988;Harrison & Jankowska, 1989;Riddell, Jankowska & Eide, 1992). Group II muscle afferent fibres have also been found to have direct contacts with neurones within the dorsal horn, the intermediate zone, Clarke's column and motor nuclei within the S1 to L3 segments (Coombs, Curtis & Landgren, 1956;Eccles, Oscarsson & Willis, 1961;Fu, Santini & Schomburg, 1974;Kirkwood & Sears, 1975;Stauffer, Watt, Taylor, Reinking & Stuart, 1976;Lundberg, Malmgren & Schomburg, 1977Munson, Fleshman & Sypert, 1980;b, 1988Jankowska & Noga, 1990; for review see Jankowska, 1992).…”

Section: Introductionmentioning

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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Contralaterally projecting lamina VIII interneurones in middle lumbar segments in the cat

Cited by 80 publications

References 11 publications

Neuronal Basis of Crossed Actions from the Reticular Formation on Feline Hindlimb Motoneurons

Neuronal Basis of Crossed Actions from the Reticular Formation on Feline Hindlimb Motoneurons

Crossed actions on group II‐activated interneurones in the midlumbar segments of the cat spinal cord.

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

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