The anatomical organization of hindlimb motoneurons in the lumbar spinal cord of the frog, <i>Rana catesbiana</i>

Cruce, William L.R.

doi:10.1002/cne.901530106

Cited by 117 publications

(51 citation statements)

References 49 publications

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“…In order to compensate for the variability in segmental innervation patterns that exists even in normal limbs (Cruce, 1974), comparisons were limited to limbs that fell into either of 2 categories: (1) those with a C-or D-type lumbar plexus (Cruce, 1974), in which axons are supplied to the plexus in equal numbers by spinal nerves 9 and 10, and in lesser numbers by 8; and (2) limbs with an A-type plexus, in which axons are supplied in equal numbers by 8 and 9, and in lesser numbers by 10. Limbs with other plexus types were encountered too infrequently to The segmental innervation patterns for all 17 hindlimb nerves in limbs with C-and D-type plexuses are shown in Figure 3.…”

Section: Resultsmentioning

confidence: 99%

“…Contained in the blocks were the lumbar VRs, dorsal roots, and spinal nerves, all in continuity with the hindlimb nerves. The lumbar plexus was exposed on each side and assigned to one of the 7 types described by Cruce (1974) on the basis of plexus shape and the relative sizes of the lumbar spinal nerves. Plexus types A-E, which are of concern to this study, are characterized by a progressively smaller contribution from VR 8 and progressively more from VR 10.…”

Section: Methodsmentioning

confidence: 99%

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Guidance of regenerating motor axons in larval and juvenile bullfrogs

Lee

Farel

1988

J. Neurosci.

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The segmental distribution of regenerating bullfrog motor axons was mapped in advanced tadpoles and juvenile frogs by stimulating selected muscle nerves and recording from the distal ends of the 3 lumbar ventral roots (VRs) that innervate the hindlimb. When motoneurons were axotomized by VR transection, they reestablished their original innervation fields, rarely, if ever, growing beyond the territory normally supplied by their spinal segment. However, when motoneurons were axotomized in the spinal nerves at the level of the hindlimb plexus, some of them regenerated into limb nerves that lay outside the axons' normal segmental boundaries, and many regenerated into the medial femoral cutaneous nerve, a pathway normally limited to sensory axons. These observations suggest that the ultimate destinations of regenerating axons are largely determined by structures the axons encounter as they penetrate the distal nerve stumps. Thus, axons regenerating from a severed VR grow into that root's own distal stump and reinnervate the hindlimb in a manner that is segmentally appropriate; axons transected near the plexus have access to the pathways of sensory, as well as motor, axons in all 3 lumbar segments, and establish innervation fields that are inappropriate for their segment of origin and their motor function.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Guidance of regenerating motor axons in larval and juvenile bullfrogs

Lee

Farel

1988

J. Neurosci.

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“…Thus, unlike the F hip flexor and A ankle extensor synergies, hip flexor and ankle extensor motoneurons have single rostrocaudal representations (Cruce 1974). Multiple representations afford many possible synergy combinations and sequences, as a given synergy will have different overlapping and neighboring synergies in its different representations.…”

Section: Topography Of Synergiesmentioning

confidence: 99%

“…Twelve hind limb muscles were implanted: rectus internus (RI), adductor magnus (AM), semimembranosus (SM), semitendinosus (ST), iliopsoas (IP), vastus internus (VI), rectus anterior (RA), vastus externus (VE), biceps femoris (BF), sartorius (SA), gastrocnemius (GA), peroneus (PE). From individual muscles electrical stimulation (Loeb et al 2000), RI and SM are hip extensor and knee flexor, AM hip extensor, ST primarily knee flexor, IP and RA hip flexor, VI and VE knee extensor, BF and SA hip flexor and knee flexor, GA knee flexor, but primarily plantar flexor (Cruce 1974), PE knee extensor and ankle dorsiflexor (Ecker 1971;Hulshof et al 1987). After laminectomy, the dura and pia were opened ipsilaterally from the sixth to the tenth roots.…”

Section: Brain Struct Functmentioning

confidence: 99%

Synergy temporal sequences and topography in the spinal cord: evidence for a traveling wave in frog locomotion

et al. 2015

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Locomotion is produced by a central pattern generator. Its spinal cord organization is generally considered to be distributed, with more rhythmogenic rostral lumbar segments. While this produces a rostrocaudally traveling wave in undulating species, this is not thought to occur in limbed vertebrates, with the exception of the interneuronal traveling wave demonstrated in fictive cat scratching (Cuellar et al. J Neurosci 29:798-810, 2009). Here, we reexamine this hypothesis in the frog, using the seven muscle synergies A to G previously identified with intraspinal NMDA (Saltiel et al. J Neurophysiol 85:605-619, 2001). We find that locomotion consists of a sequence of synergy activations (A-B-G-A-F-E-G). The same sequence is observed when focal NMDA iontophoresis in the spinal cord elicits a caudal extensionlateral force-flexion cycle (flexion onset without the C synergy). Examining the early NMDA-evoked motor output at 110 sites reveals a rostrocaudal topographic organization of synergy encoding by the lumbar cord. Each synergy is preferentially activated from distinct regions, which may be multiple, and partially overlap between different synergies. Comparing the sequence of synergy activation in locomotion with their spinal cord topography suggests that the locomotor output is achieved by a rostrocaudally traveling wave of activation in the swing-stance cycle. A two-layer circuitry model, based on this topography and a traveling wave reproduces this output and explores its possible modifications under different afferent inputs. Our results and simulations suggest that a rostrocaudally traveling wave of excitation takes advantage of the topography of interneuronal regions encoding synergies, to activate them in the proper sequence for locomotion.

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“…on functional organization of the spinal motor system have been done from physiological and anatomical points of view (1)(2)(3)(4). It was demonstrated in the am phibian that the spinal cord has the ability to produce the general pattern of stepping without receiving the controls from the higher center and signals from the peripheral sensory organs (3).…”

Section: Investigationsmentioning

confidence: 99%

Effects of Excitatory Transmitter Candidates on Frog Spinal Motor Function

Kim

Kudo

Fukuda

1979

Japanese Journal of Pharmacology

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Abstract-Thepropriospinal motor function of the frog spinal cord was investigated pharmacologically in the isolated spinal cord-nerve-muscle preparation.In the preparation with a pair of antagonistic muscles, the tissues showed reciprocal con tractions in response to the spontaneous discharges from the ventral root. M. tibialis anterior responded to the discharges from the ventral root and showed slow con tractions.Contractions of the m. gastrocnemius were much less frequent but the movement was rapid and strong. The addition of acetylcholine (10-4-10-3 M) to the medium, perfusing the spinal cord, resulted in a predominant excitation of m. tibialis anterior.Carbamylcholine (10-s M) and bethanechol (10-4 M) induced rhythmical contractions in m. tibialis anterior and depressed the movement of m. gastrocnemius. These effects were blocked by atropine (10-5 M). Serotonin (10-5 M) exerted a strong facilitatory effect on both muscles which contracted reciprocally during this treatment. L-Glutamate (10-4-10-3 M) induced a transient synchronous contraction in both muscles. By means of the sucrose-gap method, cholinomimetics and serotonin proved to have no direct effect on the motoneuron, while L-glutamate had a direct effect. Results suggest that propriospinal controlling mechanisms, regulated via serotonergic and cholinergic pathways exist and drive co-ordinate muscle movement.Investigations on functional organization of the spinal motor system have been done from physiological and anatomical points of view (1-4). It was demonstrated in the am phibian that the spinal cord has the ability to produce the general pattern of stepping without receiving the controls from the higher center and signals from the peripheral sensory organs (3). There is, however, little pharmacological documentation. We attempted to ascertain physiological and anatomical aspects on the propriospinal motor control system from a pharmacological point of view.In the present study, we employed the isolated spinal cord preparation (5, 6) and the preparation with innervated muscles (7). As the preparation with two antagonistic muscles was found to maintain reciprocal contractions following spontaneous discharges from the spinal cord, the preparation was thought to be appropriate for investigating the motor function. The effects of excitatory transmitter candidates on the preparation were examined and the possible roles of these candidates on the motor control system of the amphibian spinal cord are discussed.

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The anatomical organization of hindlimb motoneurons in the lumbar spinal cord of the frog, Rana catesbiana

Cited by 117 publications

References 49 publications

Guidance of regenerating motor axons in larval and juvenile bullfrogs

Guidance of regenerating motor axons in larval and juvenile bullfrogs

Synergy temporal sequences and topography in the spinal cord: evidence for a traveling wave in frog locomotion

Effects of Excitatory Transmitter Candidates on Frog Spinal Motor Function

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