Structural properties of the corticospinal tract in the human brain: a magnetic resonance imaging study at 7 Tesla

Hervé, Pierre‐Yves; Cox, Eleanor; Lotfipour, Ashley K.; Mougin, Olivier; Bowtell, Richard; Gowland, Penny A.; Paus, Tomáš

doi:10.1007/s00429-011-0306-0

Cited by 15 publications

(4 citation statements)

References 32 publications

(36 reference statements)

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“…As a result, parallel fibre arrangements, indicated by a low ODI, like in the PLIC, resulted in high FA, based on low radial and high parallel diffusivity as modelled by the diffusion tensor. These results are in line with previous diffusion studies of the CST, which showed high anisotropy at the level of the PLIC and low anisotropy at the level of the centrum semiovale [62,64,65]. On the other hand, in voxels with more complex fibre orientations, like crossings and fanning in the frontal WM and centrum semiovale level of the CST, corresponding FA and eigenvalues are highly influenced by the inhomogeneity of fibre orientations, making them difficult to interpret [44,62].…”

Section: Discussionsupporting

confidence: 93%

Assessing White Matter Microstructure in Brain Regions with Different Myelin Architecture Using MRI

et al. 2016

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ObjectiveWe investigate how known differences in myelin architecture between regions along the cortico-spinal tract and frontal white matter (WM) in 19 healthy adolescents are reflected in several quantitative MRI parameters that have been proposed to non-invasively probe WM microstructure. In a clinically feasible scan time, both conventional imaging sequences as well as microstructural MRI parameters were assessed in order to quantitatively characterise WM regions that are known to differ in the thickness of their myelin sheaths, and in the presence of crossing or parallel fibre organisation.ResultsWe found that diffusion imaging, MR spectroscopy (MRS), myelin water fraction (MWF), Magnetization Transfer Imaging, and Quantitative Susceptibility Mapping were myelin-sensitive in different ways, giving complementary information for characterising WM microstructure with different underlying fibre architecture. From the diffusion parameters, neurite density (NODDI) was found to be more sensitive than fractional anisotropy (FA), underlining the limitation of FA in WM crossing fibre regions. In terms of sensitivity to different myelin content, we found that MWF, the mean diffusivity and chemical-shift imaging based MRS yielded the best discrimination between areas.ConclusionMultimodal assessment of WM microstructure was possible within clinically feasible scan times using a broad combination of quantitative microstructural MRI sequences. By assessing new microstructural WM parameters we were able to provide normative data and discuss their interpretation in regions with different myelin architecture, as well as their possible application as biomarker for WM disorders.

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Section: Discussionsupporting

confidence: 93%

Assessing White Matter Microstructure in Brain Regions with Different Myelin Architecture Using MRI

et al. 2016

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“…Next, we predicted that white matter regions occupied by large-diameter axons would have a lower concentration of myelin (Paus and Toro, 2009). We confirmed this prediction indirectly by observing age-related changes in the “whiteness” of the large-axon cortico-spinal tract (Herve et al, 2009) and, more directly, by showing that this fiber tract, assessed at the level of the internal capsule, has lower MTR values and longer T2 relaxation times than the adjacent (smaller axon) white matter (Herve et al, 2011). We speculated that the presumed testosterone-induced changes in axonal diameter during male adolescence increase the probability of a suboptimal g ratio in the large-diameter fibers and, in turn, decrease conduction velocity in these fibers, as well as perturb axonal transport in these axons (Paus and Toro, 2009).…”

Section: Sex Differences and The Adolescent Brain In Humanssupporting

confidence: 62%

A Comparative, Developmental, and Clinical Perspective of Neurobehavioral Sexual Dimorphisms

Viveros¹,

Mendrek²,

Paus³

et al. 2012

Front. Neurosci.

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Women and men differ in a wide variety of behavioral traits and in their vulnerability to developing certain mental disorders. This review endeavors to explore how recent preclinical and clinical research findings have enhanced our understanding of the factors that underlie these disparities. We start with a brief overview of some of the important genetic, molecular, and hormonal determinants that contribute to the process of sexual differentiation. We then discuss the importance of animal models in studying the mechanisms responsible for sex differences in neuropsychiatric disorders (e.g., drug dependence) – with a special emphasis on experimental models based on the neurodevelopmental and “three hits” hypotheses. Next, we describe the most common brain phenotypes observed in vivo with magnetic resonance imaging. We discuss the challenges in interpreting these phenotypes vis-à-vis the underlying neurobiology and revisit the known sex differences in brain structure from birth, through adolescence, and into adulthood. This is followed by a presentation of pertinent clinical and epidemiological data that point to important sex differences in the prevalence, course, and expression of psychopathologies such as schizophrenia, and mood disorders including major depression and posttraumatic stress disorder. Recent evidence implies that mood disorders and psychosis share some common genetic predispositions and neurobiological bases. Therefore, modern research is emphasizing dimensional representation of mental disorders and conceptualization of schizophrenia and major depression as a continuum of cognitive deficits and neurobiological abnormalities. Herein, we examine available evidence on cerebral sexual dimorphism to verify if sex differences vary quantitatively and/or qualitatively along the psychoses-depression continuum. Finally, sex differences in the prevalence of posttraumatic disorder and drug abuse have been described, and we consider the genomic and molecular data supporting these differences.

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“…Early neuroimaging studies with T1 and T2 MRI sequences evidenced at this exact location an hypersignal corresponding to the highly myelinated PyT fibers (Curnes et al, 1988;Mirowitz et al, 1989;Yagishita et al, 1994). Recent studies have used this hypersignal as a marker to delineate the CST in order to study its asymmetry (Hervé et al, 2009;Hervé et al, 2011). Below the internal capsule, CST and CBT fibers enter the pons by passing through the feet of the cerebral peduncle (Dejerine and Dejerine-Klumpke, 1901).…”

Section: Introductionmentioning

confidence: 99%

A population-based atlas of the human pyramidal tract in 410 healthy participants

et al. 2018

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With the advances in diffusion MRI and tractography, numerous atlases of the human pyramidal tract (PyT) have been proposed but the inherent limitation of tractography to resolve crisscrossed bundles within the centrum semiovale have so far prevented the complete description of the most lateral PyT projections. Here, we combined a precise manual positioning of individual subcortical regions of interest along the descending pathway of the PyT with a new bundle-specific tractography algorithm. This later is based on anatomical priors to improve streamlines tracking in crossing areas. We then extracted both left and right PyT in a large cohort of 410 healthy participants and built a probabilistic atlas of the whole-fanning PyT with a complete description of its most cortico-lateral projections. Clinical applications are envisaged, the whole-fanning probabilistic PyT atlas being likely a better marker of corticospinal integrity metrics than those currently used within the frame of prediction of post-stroke motor recovery. The present probabilistic PyT, freely available, provides an interesting tool for clinical applications in order to locate specific PyT damage and its impact to the short and long-term motor recovery after stroke.

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Structural properties of the corticospinal tract in the human brain: a magnetic resonance imaging study at 7 Tesla

Cited by 15 publications

References 32 publications

Assessing White Matter Microstructure in Brain Regions with Different Myelin Architecture Using MRI

Assessing White Matter Microstructure in Brain Regions with Different Myelin Architecture Using MRI

A Comparative, Developmental, and Clinical Perspective of Neurobehavioral Sexual Dimorphisms

A population-based atlas of the human pyramidal tract in 410 healthy participants

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