Nerve roots and nuclear groups in the spinal cord of the pigeon

Huber, John Franklin

doi:10.1002/cne.900650109

Cited by 94 publications

(35 citation statements)

References 15 publications

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“…Cells in the ventral horn of the brachial enlargement segregate into a medial motor column and a lateral motor column as reported for pigeons [Huber, 1936;Leonard and Cohen, 1975]. Ipsilateral soaks of the SB and TB nerves labeled motoneuron cells in the ipsilateral ventral horn only.…”

Section: Organization Of Motor Nucleimentioning

confidence: 83%

Neuromuscular Correlates to the Evolution of Flapping Flight in Birds

Goslow

Wilson

Poore³

2000

Brain Behav Evol

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The neuromotor pattern (i.e. the onset/offset of muscle contraction within the locomotor cycle) is conserved for some homologous muscles of the tetrapod shoulder but not others in the transition from terrestrial locomotion to flight. Here we test for three shoulder muscles of the European starling (Sturnus vulgaris) to determine whether retention of, or deviation from, a conserved neuromotor pattern can be predicted on the basis of the location of the muscle’s motor nucleus within the motor column and the histochemical profile of its constituent muscle fibers. The M. supracoracoideus, the major wing elevator, illustrates a neuromotor pattern that has shifted in its timing within the limb movement cycle. Of the two heads of the triceps, the electrical activity pattern of M. humerotriceps is conserved during the transition, whereas that of the M. scapulotriceps is not. We reacted serial sections of each muscle for myosin adenosine triphosphotase (ATPase), nicotinamide adenine dinucleotide diaphorase (NADH-D), and α-glycerophosphate dehydrogenase (α-GPD) to characterize all muscles into two fiber types: fast glycolytic (FG) and fast oxidative glycolytic (FOG). We used retrograde axonal tracers to determine the longitudinal distribution and topographical organization of the motoneurons within the motor column in the spinal cord. The histochemical profile of each muscle studied is unique and is statistically different from its homologue in non-avian tetrapods. Compared to non-avian tetrapods, the spatial location of the motor nucleus of the supracoracoideus is conserved. The topology of the two heads of the triceps is fundamentally conserved relative to the other test muscles, but relative to one another there is some spatial segregation which might reflect their respective functional specializations. These data indicate that an evolutionary change in neuromotor pattern can occur without a corresponding topological reorganization of a muscle’s motor nucleus within the motor column. Nor can the histochemical profile of homologous muscles be used to predict their neuromotor pattern in the transition from terrestrial locomotion to flight. These findings suggest that evolutionary change in neuromotor outflow relates to altered synaptic input from supraspinal or segmental sources or by alteration of factors intrinsic to individual motoneurons.

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Section: Organization Of Motor Nucleimentioning

confidence: 83%

Neuromuscular Correlates to the Evolution of Flapping Flight in Birds

Goslow

Wilson

Poore³

2000

Brain Behav Evol

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“…In both domestic fowl [Ohomori et al, 1982;Straznicky and Tay, 1983] and pigeons [Huber, 1936;Leonard and Cohen, 1975;Sokoloff et al, 1989] lamina IX of the ventral horn of the spinal cord in the region of the brachial plexus is laterally expanded (fig. 6).…”

Section: Avian Motor Pool Topographymentioning

confidence: 99%

Topographic Position of Forelimb Motoneuron Pools Is Conserved in Vertebrate Evolution

et al. 1998

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The neuromotor conservatism hypothesis predicts that neuromotor patterns in homologous tetrapod muscles are conserved evolutionarily despite the musculoskeletal modifications of vertebrate limbs. A complete description of the anatomical organization of the neurons innervating homologous limb muscles is a prerequisite to any test of the neuromotor conservatism hypothesis. This study uses the retrograde neuronal tracer WGA-HRP to selectively label the motor neuron pools of seven homologous forelimb muscles in mice (Mus musculus) and iguanas (Iguana iguana): Mm. pectoralis, spinodeltoideus, biceps brachii, lateral and long heads of triceps brachii, and the supraspinatus and infraspinatus (in mice) or their reptilian homolog, the supracoracoideus (in iguanas). In vertebrates, motoneurons are arranged in longitudinal columns of cells in the ventral horn of the spinal cord. Mouse motor pools average 1,952 μm in length, except the pectoralis pool which averaged 2,949 μm in length. Iguana pools average 3,196 μm in length. The number of neurons per pool ranged from 70–199 in mice and from 58–114 neurons in iguanas. In both iguanas and mice the motor pools for the spinodeltoids, biceps, and the supracoracoideus (or its mammalian homologs) lie anterior to the pectoralis and triceps motor pools. In the transverse plane, the pectoralis pool lies medial to those of the triceps. The pools of the biceps and spinodeltoids are located dorsal and lateral to those of the pectoralis and supracoracoideus (or its homologs in mammals). The resulting motor pool maps support the hypothesis that the anatomical organization of motoneurons in ancestral reptiles has been retained in these two tetrapod descendents.

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“…In the pigeon Huber (1936) differentiated between marginal paragriseal cells, which appear in close association with the dentate ligament, and scattered paragriseal cells, which lie in the white matter. Scattered paragriseal cells appear caudal to the cervical segments and increase gradually in number down to the lumbosacral enlargement where they are most numerous.…”

mentioning

confidence: 98%

“…In the avian spinal cord there is a significant number of neuronal perikarya, which lie outside the gray substance (Huber, 1936). In the pigeon Huber (1936) differentiated between marginal paragriseal cells, which appear in close association with the dentate ligament, and scattered paragriseal cells, which lie in the white matter.…”

mentioning

confidence: 98%

Projections of the marginal nuclei in the spinal cord of the pigeon

Necker

1997

J. Comp. Neurol.

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In the avian spinal cord, there are several groups of neurons lying outside the central gray substance. The most conspicuous ones lie at the very margin of the ventrolateral cord. In the lumbosacral spinal cord, these marginal nuclei protrude into the vertebral canal to form accessory lobes. The projections of these marginal nuclei were studied in the pigeon by neuroanatomical tracing methods. Anterograde transport of tracer injected into the lumbosacral accessory lobes showed that these neurons project to the contralateral medial ventral gray and to paragriseal cells located in the contralateral ventral and lateral white matter of lumbosacral segments. Double-labeling experiments disclosed that lumbosacral paragriseal cells projecting to the cerebellum are contacted by accessory lobe axon terminals. The projection of cervical marginal nuclei was studied with retrograde transport of tracers applied to the spinal tracts in the lateral funiculus. Retrogradely labeled cells were found in contralateral marginal nuclei of both rostral and caudal segments. All marginal nuclei have an ascending and a descending projection spanning about five segments each. The possible role of marginal nuclei in sensorimotor circuits is discussed.

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Nerve roots and nuclear groups in the spinal cord of the pigeon

Cited by 94 publications

References 15 publications

Neuromuscular Correlates to the Evolution of Flapping Flight in Birds

Neuromuscular Correlates to the Evolution of Flapping Flight in Birds

Topographic Position of Forelimb Motoneuron Pools Is Conserved in Vertebrate Evolution

Projections of the marginal nuclei in the spinal cord of the pigeon

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