Postnatal growth of corticospinal axons in the spinal cord of developing mice

Gianino, Scott M.; Stein, Stuart A.; Li, Huaying; Lü, Xiaobin; Biesiada, Elzbieta; Ułas, J.; Xu, Xiao–Ming

doi:10.1016/s0165-3806(98)00168-0

Cited by 65 publications

(62 citation statements)

References 44 publications

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“…In rats, the extension of the corticospinal tract was found to reach the caudal pole of the medulla at about the time of birth (E21 and P0) [de Kort et al, 1985]. In mice, the leading corticospinal tract axons have reached the 8th cervical segment at P2 [Gianino et al, 1999]. In our study of the brains of P1 mice there was a small bulge on the surface of the hindbrain ( fig.…”

Section: The Development Of the Mouse Arcuate Nucleusmentioning

confidence: 44%

The Arcuate Nucleus of the C57BL/6J Mouse Hindbrain Is a Displaced Part of the Inferior Olive

Watson

2012

Brain Behav Evol

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The arcuate nucleus is a prominent cell group in the human hindbrain, characterized by its position on the pial surface of the pyramid. It is considered to be a precerebellar nucleus and has been implicated in the pathology of several disorders of respiration. An arcuate nucleus has not been convincingly demonstrated in other mammals, but we have found a similarly positioned nucleus in the C57BL/6J mouse. The mouse arcuate nucleus consists of a variable group of neurons lying on the pial surface of the pyramid. The nucleus is continuous with the ventrolateral part of the principal nucleus of the inferior olive and both groups are calbindin positive. At first we thought that this mouse nucleus was homologous with the human arcuate nucleus, but we have discovered that the neurons of the human nucleus are calbindin negative, and are therefore not olivary in nature. We have compared the mouse arcuate neurons with those of the inferior olive in terms of molecular markers and cerebellar projection. The neurons of the arcuate nucleus and of the inferior olive share three major characteristics: they both contain neurons utilizing glutamate, serotonin or acetylcholine as neurotransmitters; they both project to the contralateral cerebellum, and they both express a number of genes not present in the major mossy fiber issuing precerebellar nuclei. Most importantly, both cell groups express calbindin in an area of the ventral hindbrain almost completely devoid of calbindin-positive cells. We conclude that the neurons of the hindbrain mouse arcuate nucleus are a displaced part of the inferior olive, possibly separated by the caudal growth of the pyramidal tract during development. The arcuate nucleus reported in the C57BL/6J mouse can therefore be regarded as a subgroup of the rostral inferior olive, closely allied with the ventral tier of the principal nucleus.

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Section: The Development Of the Mouse Arcuate Nucleusmentioning

confidence: 44%

The Arcuate Nucleus of the C57BL/6J Mouse Hindbrain Is a Displaced Part of the Inferior Olive

Watson

2012

Brain Behav Evol

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“…At P11, the CST has innervated the lumbar enlargement of the cord, where it is more loosely fasciculated and is undergoing branching (11). EphA4 immunoreactivity at this age was still strong (Fig.…”

Section: Epha4 Expression Decreases In the Spinal Cord At The Time Ofmentioning

confidence: 94%

“…To examine these possibilities, we analyzed EphA4 expression in the developing neonatal spinal cord. By P5, the majority of axons have arrived in the cervical spinal cord, and the forelimb axons have commenced collateral branching into the gray matter (11). In the cervical DF at this age, there is strong EphA4 expression, particularly in the most ventral region, which contains the growing CST axons (Fig.…”

Section: Epha4 Expression Decreases In the Spinal Cord At The Time Ofmentioning

confidence: 96%

“…5, which is published as supporting information on the PNAS web site). Biotinylated dextran amine (BDA) was injected into the anterior cortex of EphA4 Ϫ/Ϫ and control mice at postnatal day (P)1, and spinal cords were examined at both P5 and P7, which spans the time of collateral branching of CST axons in the cervical spinal cord (11). Branches from the axon shaft are present at these times (Fig.…”

Section: Loss Of Topographically Specific Branching Of Cst Axons In Smentioning

confidence: 99%

“…To examine this possibility, we counted the number of labeled hindlimb axons that had reached the lumbar cord at P7 and expressed this number as a percentage of labeled axons in the cervical cord in the same animal; P7 is a time when CST axons have reached the lumbar cord but degeneration of the primary axon shaft has not yet occurred (11,12). A similar percentage of axons had reached the lumbar cord at P7 in both EphA4 Ϫ/Ϫ mice (84 Ϯ 12%, n ϭ 3) and their heterozygous littermates (88 Ϯ 16%, n ϭ 4), which is consistent with our findings described above that EphA4 is not involved in guiding CST axons down the spinal cord.…”

Section: Loss Of Topographically Specific Branching Of Cst Axons In Smentioning

confidence: 99%

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Eph tyrosine kinase receptor EphA4 is required for the topographic mapping of the corticospinal tract

Canty

Greferath²,

Turnley³

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

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Fine movement in the body is controlled by the motor cortex, which signals in a topographically specific manner to neurons in the spinal cord by means of the corticospinal tract (CST). How the correct topography of the CST is established is unknown. To investigate the possibility that the Eph tyrosine kinase receptor EphA4 is involved in this process, we have traced CST axons in mice in which the EphA4 gene has been deleted. The forelimb subpopulation of CST axons is unaffected in the EphA4 ؊/؊ mice, but the hindlimb subpopulation branches too early within the cord, both temporally and spatially. EphA4 shows a dynamic expression pattern in the environment of the developing CST in the spinal cord: high at the time of forelimb branching and down-regulated before hindlimb branching. To examine whether the fore-and hindlimb subpopulations of CST axons respond differently to EphA4 in their environment, neurons from fore-and hindlimb motor cortex were cultured on a substrate containing EphA4. Neurons from the hindlimb cortex showed reduced branching on the EphA4 substrate compared with their forelimb counterparts. Neurons from the hindlimb cortex express ephrinA5, a high-affinity ligand for EphA4, at higher levels compared with forelimb cortex neurons, and this expression is down-regulated before hindlimb branching. Together, these findings suggest that EphA4 regulates topographic mapping of the CST by controlling the branching of CST axons in the spinal cord.motor control ͉ axon guidance ͉ spinal cord ͉ neuronal development F ine voluntary movement is controlled by the motor areas of the cerebral cortex. The motor cortex has a somatotopic arrangement in which different areas control movements of different parts of the body. For those regions of the motor cortex that control movement of the muscles of the trunk and limbs, the cortical commands travel through the brain in the corticospinal tract (CST) to terminate in topographically specific locations along the spinal cord. There are two major termination zones in the spinal cord, in the cervical and lumbar regions, that carry information for the fore-and hindlimbs, respectively. In primates, the CST axons terminate directly on spinal motor neurons and interneurons, whereas in other mammals, termination occurs almost exclusively on interneurons in the dorsal horns. The CST thus provides the most direct route for cortical control of movement and is the longest and largest descending tract from the brain.During development, growing CST axons must navigate long distances through the brain and spinal cord to reach their gray-matter target cells. How they are successfully guided to their target locations in a topographically correct pattern is unknown. In rodents, CST axons descend through the spinal cord in the ventral aspect of the dorsal funiculus (DF). The axons then exit the DF in topographically specific locations along the cord by means of collateral branching. Several in vivo and in vitro explant studies suggest that as-yet-unidentified diffusible and͞or contact-med...

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Cytoarchitecture of the Spinal Cord of the Postnatal (P4) Mouse

Şengül

Puchalski

Watson

2012

The Anatomical Record

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Interpretation of the new wealth of gene expression and molecular mechanisms in the developing mouse spinal cord requires an accurate anatomical base on which data can be mapped. Therefore, we have assembled a spinal cord atlas of the P4 mouse to facilitate direct comparison with the adult specimens and to contribute to studies of the development of the mouse spinal cord. This study presents the anatomy of the spinal cord of the P4 C57Bl/6J mouse using Nissl and acetyl cholinesterase-stained sections. It includes a detailed map of the laminar organization of selected spinal cord segments and a description of named cell groups of the spinal cord such as the central cervical (CeCv), lateral spinal nucleus, lateral cervical, and dorsal nuclei. The motor neuron groups have also been identified according to the muscle groups they are likely Abbreviations used: 1Sp ¼ lamina 1 of the spinal gray; 2Sp ¼ lamina 2 of the spinal gray; 2SpI ¼ lamina 2 of the spinal gray, inner part; 2Sp ¼ lamina 2 of the spinal gray, outer part; 3Sp ¼ lamina 3 of the spinal gray; 4Sp ¼ lamina 4 of the spinal gray; 5Sp ¼ lamina 5 of the spinal gray; 5SpL ¼ lamina 5 of the spinal gray, lateral part; 5SpM ¼ lamina 5 of the spinal gray, medial part; 6Sp ¼lamina 6 of the spinal gray; 6SpL ¼ lamina 6 of the spinal gray, lateral part; 6SpM ¼ lamina 6 of the spinal gray, medial part; 7Sp ¼ lamina 7 of the spinal gray; 8Sp ¼ lamina 8 of the spinal gray; 9Sp ¼ lamina 9 of the spinal gray; 10Sp ¼ lamina 10 of the spinal gray; Ad9 ¼ adductor motor neurons of lamina 9, asp, anterior spinal artery; Ax9 ¼ axial muscle motor neurons of lamina 9; Bi9 ¼ biceps motor neurons of lamina 9; CC ¼ central canal; CeCv ¼ central cervical nucleus; CEx9 ¼ crural extensor motor neurons of lamina 9; CFl9 ¼ crural flexor motor neurons of lamina 9; Cr9 ¼ cremaster motor neurons of lamina 9; cu ¼ cuneate fasciculus; D ¼ dorsal nucleus (Clarke); dcs ¼ dorsal corticospinal tract; De9 ¼ deltoid motor neurons of lamina 9; df ¼ dorsal funiculus; dl ¼ dorsolateral fasciculus (Lissauer); dr ¼ dorsal root; ExA9 ¼ external anal sphincter motor neurons of lamina 9; ExU9 ¼ external urethral sphincter motor neurons of lamina 9; FEx9 ¼ forearm extensor motor neurons of lamina 9; FFl9 ¼ forearm flexor motor neurons of lamina 9; Gl9 ¼ gluteal motor neurons of lamina 9; gr ¼ gracile fasciculus; Hm9 ¼ hamstring motor neurons of lamina 9; IB ¼ internal basilar nucleus; ICl ¼ intercalated nucleus; IClPe ¼ intercalated nucleus, paraependymal part; ICo9 ¼ intercostal muscle motor neurons of lamina 9; IH9 ¼ infrahyoid muscle motor neurons of lamina 9; IML ¼ intermediolateral column; IMM ¼ intermediomedial column; LatC ¼ lateral cervical nucleus; LD9 ¼ latissimus dorsi motor neurons of lamina 9; LDCom ¼ lumbar dorsal commissural nucleus; lf ¼ lateral funiculus; LPrCb ¼ lumbar precerebellar nucleus, LS9 ¼ levator scapulae motor neurons of lamina 9; LSp ¼ lateral spinal nucleus; Man9 ¼ manus motor neurons of lamina 9; Pec9 ¼ pectoral muscle motor neurons of lamina 9; Pes9 ¼ pes motor neuro...

show abstract

Postnatal growth of corticospinal axons in the spinal cord of developing mice

Cited by 65 publications

References 44 publications

The Arcuate Nucleus of the C57BL/6J Mouse Hindbrain Is a Displaced Part of the Inferior Olive

The Arcuate Nucleus of the C57BL/6J Mouse Hindbrain Is a Displaced Part of the Inferior Olive

Eph tyrosine kinase receptor EphA4 is required for the topographic mapping of the corticospinal tract

Cytoarchitecture of the Spinal Cord of the Postnatal (P4) Mouse

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