Development and malformations of the human pyramidal tract

Donkelaar, Hans J. ten; Lammens, Martin; Wesseling, Pieter; Hori, Akira; Keyser, A.; Rotteveel, J.J.

doi:10.1007/s00415-004-0653-3

Cited by 117 publications

(71 citation statements)

References 137 publications

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“…The transcriptional mirroring between the spinal cord and hindbrain is broadly consistent with the well-established crossing over (decussation) of structure and function in the inferior hindbrain (42). Because the corticospinal tract only arrives at the inferior hindbrain by CS23 (17), any molecular asymmetry in descending axons would not be expected to affect the spinal cord directly, although it may affect the hindbrain by CS23. Therefore, in the spinal cord particularly, transcriptional asymmetry from CS13 to CS23 is likely to originate independently of top-down forebrain influences.…”

Section: Discussionmentioning

confidence: 99%

“…One study, however, suggested that in 12-to 17-week-old fetuses the right cerebral cortex matures faster than the left one in terms of gene expression profiles (16). However, the corticospinal tract, which descends from the motor and somatosensory cerebral cortices to the spinal cord, only reaches the point of left-right crossover in the inferior hindbrain at 8 weeks postconception -the age of observed lateralization of arm movements-but does not yet extend into the spinal cord (17). Thus, lateralization of motor behavior at this stage is unlikely to reflect topdown asymmetry projected from the cerebral cortex.…”

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confidence: 99%

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Left–Right Asymmetry of Maturation Rates in Human Embryonic Neural Development

Kovel

Lisgo²,

Karlebach

et al. 2017

Biological Psychiatry

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BACKGROUND: Left-right asymmetry is a fundamental organizing feature of the human brain, and neuropsychiatric disorders such as schizophrenia sometimes involve alterations of brain asymmetry. As early as 8 weeks postconception, the majority of human fetuses move their right arms more than their left arms, but because nerve fiber tracts are still descending from the forebrain at this stage, spinal-muscular asymmetries are likely to play an important developmental role. METHODS: We used RNA sequencing to measure gene expression levels in the left and right spinal cords, and the left and right hindbrains, of 18 postmortem human embryos aged 4 to 8 weeks postconception. Genes showing embryonic lateralization were tested for an enrichment of signals in genome-wide association data for schizophrenia. RESULTS:The left side of the embryonic spinal cord was found to mature faster than the right side. Both sides transitioned from transcriptional profiles associated with cell division and proliferation at earlier stages to neuronal differentiation and function at later stages, but the two sides were not in synchrony (p 5 2.2 E-161). The hindbrain showed a left-right mirrored pattern compared with the spinal cord, consistent with the well-known crossing over of function between these two structures. Genes that showed lateralization in the embryonic spinal cord were enriched for association signals with schizophrenia (p 5 4.3 E-05). CONCLUSIONS: These are the earliest stage left-right differences of human neural development ever reported. Disruption of the lateralized developmental program may play a role in the genetic susceptibility to schizophrenia.

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Left–Right Asymmetry of Maturation Rates in Human Embryonic Neural Development

Kovel

Lisgo²,

Karlebach

et al. 2017

Biological Psychiatry

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“…Aberrant wiring of neuronal circuits can lead to abnormal behavior and neurological disease (Jen et al, 2004;Ponnio and Conneely, 2004;ten Donkelaar et al, 2004). Left-right (L-R) differences in fiber tracts have been correlated with hemispheric specialization of the brain (Nucifora et al, 2005), and presumably underlie asymmetries in axonal connections.…”

Section: Development Of Correct Connections Between Neurons Is Cruciamentioning

confidence: 99%

Neuropilin asymmetry mediates a left-right difference in habenular connectivity

Kuan

Moens

et al. 2007

Development

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The medial habenular nuclei of the zebrafish diencephalon, which lie bilateral to the pineal complex, exhibit left-right differences in their neuroanatomy, gene expression profiles and axonal projections to the unpaired midbrain target -the interpeduncular nucleus (IPN). Efferents from the left habenula terminate along the entire dorsoventral extent of the IPN, whereas axons from the right habenula project only to the ventral IPN. How this left-right difference in connectivity is established and the factors involved in differential target recognition are unknown. Prior to IPN innervation, we find that only the left habenula expresses the zebrafish homologue of Neuropilin1a (Nrp1a), a receptor for class III Semaphorins (Sema3s). Directional asymmetry of nrp1a expression relies on Nodal signaling and the presence of the left-sided parapineal organ. Loss of Nrp1a, through parapineal ablation or depletion by antisense morpholinos, prevents left habenular neurons from projecting to the dorsal IPN. Selective depletion of Sema3D, but not of other Sema family members, similarly disrupts innervation of the dorsal IPN. Conversely, Sema3D overexpression results in left habenular projections that extend to the dorsal IPN, as well as beyond the target. The results indicate that Sema3D acts in concert with Nrp1a to guide neurons on the left side of the brain to innervate the target nucleus differently than those on the right side.

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“…At term, the deep structures we studied (portions of the corpus callosum and internal capsule) are still immature with respect to each of these cytologic and histologic features of WM [5]. Nevertheless, each deep WM structure is well established at this age, having been pioneered in the second trimester by long axonal projections arranged into relatively compact parallel bundles of axonal fascicles [29][30][31]. In contrast, the peripheral WM of the prefrontal and posterior parietal cortex that we sampled was much less developed at term, being only poorly myelinated and sparsely populated by associational fibers that have yet to establish widespread corticocortical connections [10,32].…”

Section: Status Of Cerebral Wm At Termmentioning

confidence: 99%

Diffusion Tensor Imaging Assessment of Brain White Matter Maturation During the First Postnatal Year

Provenzale

Liang²,

DeLong³

et al. 2007

American Journal of Roentgenology

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OBJECTIVE. The purpose of this study was to use diffusion-weighted and diffusion tensor imaging to investigate the status of cerebral white matter (WM) at term gestation and the rate of WM maturation throughout the first year of life in healthy infants.MATERIALS AND METHODS. Fifty-three children (35 boys) ranging in age from 1.5 weeks premature to 51.5 weeks (mean age, 22.9 weeks) underwent conventional MRI, diffusion imaging in three directions (b = 1,000 s/mm 2 ), and diffusion tensor imaging with gradient encoding in six directions, all on a 1.5-T MRI system. Apparent diffusion coefficient (ADC) and fractional anisotropy (FA) were measured in three deep WM structures (posterior limb of internal capsule, genu, and splenium of corpus callosum) and two peripheral WM regions (associational WM underlying prefrontal and posterior parietal cortex) with a standard region of interest (44 ± 4 cm 2 ). ADC and FA were expressed as a percentage of corresponding values measured in a group of healthy young adults. Mean ADC and FA values for deep and peripheral WM were plotted against gestational age normalized to term. The data were fit best with a broken-line linear regression model with a breakpoint at 100 days. ADC and FA values at term were estimated according to the intercept of the initial linear period (before day 100) with day 0. The slope of the linear fits was used to determine the rate of WM maturation in both the early and the late (after day 100) periods. Multivariate analysis of variance tests were used to compare deep and peripheral WM structures at term and at representative early and late ages (days 30 and 200) and to compare rates of ADC and FA maturation in early and late periods within the first year.RESULTS. At term, peripheral WM was less mature than deep WM according to results of extrapolation of ADC and FA values in the first 100 days of life to day 0 (p < 0.01). Mean ADC and FA value (percentage of mean adult value) for peripheral WM were 1.32 × 10 −3 mm 2 /s (163%) and 0.16 (32%), respectively, and 1.09 × 10 −3 mm 2 /s (143%) and 0.36 (54%), respectively, for deep WM. On day 30 and day 200, estimated mean ADC and FA continued to show greater diffusion (higher ADC) and less anisotropy (lower FA value) in peripheral WM (p < 0.01). During the first year of postnatal life, both ADC and FA matured at higher rates before postnatal day 100 compared with a later time. Differences were observed in rates of maturation in the first 100 days when rates of decrease in ADC and increase in FA were compared between peripheral WM and deep WM; however, the maturational trends differed whether ADC or FA was examined. The early rate of ADC decrease (maturation) was twice as great for peripheral WM than for deep WM (p < 0.01) unexpectedly, but the opposite pattern was observed for FA. The early rate of FA increase (maturation) was approximately one half as great for peripheral WM as for deep WM (p = 0.01). Throughout the rest of the first year, no differences were observed in the rates of change in either index betwee...

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Development and malformations of the human pyramidal tract

Cited by 117 publications

References 137 publications

Left–Right Asymmetry of Maturation Rates in Human Embryonic Neural Development

Left–Right Asymmetry of Maturation Rates in Human Embryonic Neural Development

Neuropilin asymmetry mediates a left-right difference in habenular connectivity

Diffusion Tensor Imaging Assessment of Brain White Matter Maturation During the First Postnatal Year

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