The rubrospinal tract. II. Facilitation of interneuronal transmission in reflex paths to motoneurones

Hongo, Tetsuro; Jankowska, E.; Lundberg, A.

doi:10.1007/bf00237321

Cited by 411 publications

(76 citation statements)

References 25 publications

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“…The polymodal character of reflexes mediated by these interneurones is further indicated by their co-excitation by impulses in other afferents (low threshold cutaneous and joint afferents, flexor reflex afferents) and by descending fibre systems, as described previously (Lundberg & Voorhoeve, 1962, Hongo et al 1969, Lundberg et al 1977, 1978 Functional differentiation of laminae V-VI interneurone8 with input from group I afferents In contrast to laminae VII interneurones which have been found to mediate only one type of reflex from Ia afferents, the reciprocal inhibition between flexors and extensors, the group I excited laminae V-VI interneurones may be interposed in several reflex pathways. Among these may be (i) interneurones projecting to motoneurones and mediating their di-and trisynaptic inhibition or excitation from lb afferents (Laporte & Lloyd, 1952, Eccles et al 1957a and di-or trisynaptic autogenetic and synergistic inhibition from Ia afferents (Fetz et al 1979) (ii), interneurones mediating presynaptic depolarization of primary afferents from group Ia and/or Ib afferents (for references see Schmidt, 1973) (iii) interneurones subserving crossed excitatory and inhibitory reflexes from group I afferents (Perl, 1958;Holmqvist, 1961, Baxendale & Rosenberg 1976, 1977 as well as (iv) interneurones transmitting information to long ascending tract cells (Eccles,Hubbard & 400 E. JANKOWSKA, T. JOHANNISSON AND J. LIPSKI Oscarsson, 1961, Lundberg & Weight, 1971.…”

Section: Discussionmentioning

confidence: 70%

“…4A and B and in Fig. 5D-E Input from other than group I fibre systems It has been established previously by indirect methods (see Lundberg, 1975) that interneurones which mediate the excitation and inhibition of motoneurones from tendon organ afferents are di-or trisynaptically excited by cutaneous afferents (Lundberg, Malmgren & Schomburg, 1977), oligosynaptically from joint afferents (Lundberg, Malmgren & Schomburg 1978), monosynaptically from the red nucleus Hongo, Jankowska & Lundberg, 1969) and mono-or oligosynaptically from the pyramidal tract (Lundberg & Voorhoeve, 1962;Illert, Lundberg & Tanaka, 1976 Only in one neurone the e.p.s.p.s from a cutaneous nerve were evoked with a shorter (0-7 msec) latency. This neurone was unfortunately lost before it was tested for antidromic invasion from the dorsal columns.…”

Section: Methodsmentioning

confidence: 85%

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Common interneurones in reflex pathways from group 1a and 1b afferents of ankle extensors in the cat.

Jankowska¹,

Johannisson²,

Lipski³

1981

The Journal of Physiology

127

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SUMMARY1. Input from group I afferents of ankle and toe extensors, other muscles, skin nerves and descending tracts to interneurones of Rexed's laminae V-VI in the cat spinal cord was analysed using intracellular recording from these interneurones. Adequate stimuli (muscle stretches) were used to activate selectively group I a muscle spindle afferents of triceps surae and plantaris while other fibre systems were excited electrically.2. Ia and lb afferents of ankle and toe extensors were found to co-excite, co-inhibit or exert opposite synaptic actions in 41, 33 and 50 %of the analysed interneurones, respectively. Taking into account both excitatory and inhibitory input from these two groups of afferents, 64 % of the interneurones appeared to be used in common in reflex pathways from muscle spindles and tendon organs ofankle and toe extensors.3. Selective input from I b afferents of triceps surae and plantaris (excitation and/or inhibition) was found in 36 % of the interneurones; there was no evidence for a similarly selective input from I a afferents. 4. A great majority (over 90 %) of the interneurones excited by group I afferents were also inhibited by group I afferents, from either the same or other muscles. 5. Both monosynaptic and disynaptic e.p.s.p.s from Ia and/or Ib afferents from other muscles and from fibres in the ipsilateral funiculi were found in a great proportion of the same interneurones, together with disynaptic e.p.s.p.s from low threshold cutaneous afferents.6. Intracellular staining with horseradish peroxidase revealed four different patterns of axonal projections of the analysed interneurones: (i) projections to motor nuclei and the intermediate region, (ii and iii) projections only to the intermediate region, locally or combined with projections to different rostro-caudal levels, and (iv) projections to the opposite side of the spinal cord.7. A large proportion of interneurones projecting to motor nuclei displayed input from both I a and I b afferents although such an input was a feature of interneurones with other projections as well. No systematic differences in the input from group I afferents were found for interneurones with different axonal projections. In contrast disynaptic e.p.s.p.s of cutaneous origin and monosynaptic e.p.s.p.s upon stimulation of ipsilateral spinal tracts appeared predominantly in interneurones projecting to motor nuclei.

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Section: Discussionmentioning

confidence: 70%

Section: Methodsmentioning

confidence: 85%

Common interneurones in reflex pathways from group 1a and 1b afferents of ankle extensors in the cat.

Jankowska¹,

Johannisson²,

Lipski³

1981

The Journal of Physiology

127

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“…However, the upper cervical DLF lesions would also have transected rubrospinal fibers, arguing against a major contribution from them. Furthermore, rubrospinal fibers decussate on exiting the nucleus before descending, and there is no information on potential ipsilateral actions adding to strong contralateral actions (Hongo et al, 1969).…”

Section: Pathways From the Corticospinal Tract To Ipsilateral Motoneumentioning

confidence: 99%

Ipsilateral Actions of Feline Corticospinal Tract Neurons on Limb Motoneurons

Edgley¹,

Jankowska²,

Hammar³

2004

J. Neurosci.

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Contralateral pyramidal tract (PT) neurons arising in the primary motor cortex are the major route through which volitional limb movements are controlled. However, the contralateral hemiparesis that follows PT neuron injury on one side may be counteracted by ipsilateral of actions of PT neurons from the undamaged side. To investigate the spinal relays through which PT neurons may influence ipsilateral motoneurons, we analyzed the synaptic actions evoked by stimulation of the ipsilateral pyramid on hindlimb motoneurons after transecting the descending fibers of the contralateral PT at a low thoracic level. The results show that ipsilateral PT neurons can affect limb motoneurons trisynaptically by activating contralaterally descending reticulospinal neurons, which in turn activate spinal commissural interneurons that project back across to motoneurons ipsilateral to the stimulated pyramidal tract. Stimulation of the pyramids alone did not evoke synaptic actions in motoneurons but potently facilitated disynaptic EPSPs and IPSPs evoked by stimulation of reticulospinal tract fibers in the medial longitudinal fascicle. In parallel with this double-crossed pathway, corticospinal neurons could also evoke ipsilateral actions via ipsilateral descending reticulospinal tract fibers, acting through ipsilaterally located spinal interneurons. Because the actions mediated by commissural interneurons were found to be stronger than those of ipsilateral premotor interneurons, the study leads to the conclusion that ipsilateral actions of corticospinal neurons via commissural interneurons may provide a better opportunity for recovery of function in hemiparesis produced by corticospinal tract injury.

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“…Voluntary muscle contractions require parallel and balanced excitation of α-and γ-motoneurons and corresponding reciprocal Ia interneurons (α-γ linkage in reciprocal Ia inhibition, Hongo et al, 1969;Hultborn et al, 1976). Renshaw cells affect all of these neurons (Hultborn et al, 1976).…”

Section: (2) Reticulospinal Control Of Interneurons In Reflex Pathwaysmentioning

confidence: 99%

“…For example, the rubrospinal and corticospinal tracts facilitate FRA pathways (Hongo et al, 1969(Hongo et al, , 1972Hultborn et al, 1976;Jankowska et al, 1976;Lundberg and Vooehoeve, 1962) so that these tracts can produce fine movements (see Jankowska, 1992). Signals from the midbrain locomotor region also excite group II interneurons (Edgley et al, 1988;Schefchyk et al, 1990) and induce rhythmic firing of reciprocal Ia interneurons (Carol and Jordan, 1987;Feldman and Orlovsky, 1975) and…”

Section: (3) Interaction Between the Reticulospinal System And Fra Symentioning

confidence: 99%

Medullary reticulospinal tract mediating a generalized motor inhibition in cats: iii. functional organization of spinal interneurons in the lower lumbar segments

2003

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The rubrospinal tract. II. Facilitation of interneuronal transmission in reflex paths to motoneurones

Cited by 411 publications

References 25 publications

Common interneurones in reflex pathways from group 1a and 1b afferents of ankle extensors in the cat.

Common interneurones in reflex pathways from group 1a and 1b afferents of ankle extensors in the cat.

Ipsilateral Actions of Feline Corticospinal Tract Neurons on Limb Motoneurons

Medullary reticulospinal tract mediating a generalized motor inhibition in cats: iii. functional organization of spinal interneurons in the lower lumbar segments

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