Nests of dividing neuroblasts sustain interneuron production for the developing human brain.

The human cortex contains inhibitory interneurons derived from the medial ganglionic eminence (MGE), a germinal zone in the embryonic ventral forebrain. How this germinal zone generates sufficient interneurons for the human brain remains unclear. We found that the human MGE (hMGE) contains nests of proliferative neuroblasts with ultrastructural and transcriptomic features that distinguish them from other progenitors in the hMGE.

Motion corrected MRI differentiates male and female human brain growth trajectories from mid-gestation.

It is of considerable scientific, medical, and societal interest to understand the developmental origins of differences between male and female brains. Here we report the use of advances in MR imaging and analysis to accurately measure global, lobe and millimetre scale growth trajectory patterns over 18 gestational weeks in normal pregnancies with repeated measures. Statistical modelling of absolute growth trajectories revealed underlying differences in many measures, potentially reflecting overall body size differences.

In utero MRI identifies consequences of early-gestation alcohol drinking on fetal brain development in rhesus macaques.

One factor that contributes to the high prevalence of fetal alcohol spectrum disorder (FASD) is binge-like consumption of alcohol before pregnancy awareness. It is known that treatments are more effective with early recognition of FASD. Recent advances in retrospective motion correction for the reconstruction of three-dimensional (3D) fetal brain MRI have led to significant improvements in the quality and resolution of anatomical and diffusion MRI of the fetal brain.

Anatomical and diffusion MRI brain atlases of the fetal rhesus macaque brain at 85, 110 and 135 days gestation.

Recent advances in image reconstruction techniques have enabled high resolution MRI studies of fetal brain development in human subjects. Rhesus macaques (Macaca mulatta) are valuable animal models for use in studies of fetal brain development due to the similarities between this species and humans in brain development and anatomy. There is a need to develop fetal brain templates for the rhesus macaque to facilitate the characterization of the normal brain growth trajectory and departures from this trajectory in rhesus models of neurodevelopmental disorders.

Challenges and Opportunities in Connectome Construction and Quantification in the Developing Human Fetal Brain.

The white matter structure of the human brain undergoes critical developmental milestones in utero, which we can observe noninvasively using diffusion-weighted magnetic resonance imaging. In order to understand this fascinating developmental process, we must establish the variability inherent in such a challenging imaging environment and how measurable quantities can be transformed into meaningful connectomes. We review techniques for reconstructing and studying the brain connectome and explore promising opportunities for in utero studies that could lead to more accurate measurement of structural properties and allow for more refined and insightful analyses of the fetal brain.

Plasma cholesterol levels and brain development in preterm newborns.

Background: To assess whether postnatal plasma cholesterol levels are associated with microstructural and macrostructural regional brain development in preterm newborns.

Methods: Sixty preterm newborns (born 24-32 weeks gestational age) were assessed using MRI studies soon after birth and again at term-equivalent age. Blood samples were obtained within 7 days of each MRI scan to analyze for plasma cholesterol and lathosterol (a marker of endogenous cholesterol synthesis) levels.

Congenital Zika virus infection as a silent pathology with loss of neurogenic output in the fetal brain.

Zika virus (ZIKV) is a flavivirus with teratogenic effects on fetal brain, but the spectrum of ZIKV-induced brain injury is unknown, particularly when ultrasound imaging is normal. In a pregnant pigtail macaque (Macaca nemestrina) model of ZIKV infection, we demonstrate that ZIKV-induced injury to fetal brain is substantial, even in the absence of microcephaly, and may be challenging to detect in a clinical setting. A common and subtle injury pattern was identified, including (i) periventricular T2-hyperintense foci and loss of fetal noncortical brain volume, (ii) injury to the ependymal epithelium with underlying gliosis and (iii) loss of late fetal neuronal progenitor cells in the subventricular zone (temporal cortex) and subgranular zone (dentate gyrus, hippocampus) with dysmorphic granule neuron patterning.

Postnatal polyunsaturated fatty acids associated with larger preterm brain tissue volumes and better outcomes.

BackgroundHuman studies investigating the link between postnatal polyunsaturated fatty acids and preterm brain growth are limited, despite emerging evidence of potential effects on outcomes.MethodsSixty preterm neonates <32 weeks gestational age with magnetic resonance imaging (MRI) scanning at near-birth and near-term age were assessed for brain tissue volumes, including cortical gray matter, white matter, deep gray matter, cerebellum, brainstem, and ventricular cerebrospinal fluid. Red blood cell fatty acid content was evaluated within 1 week of each MRI scan.

Gyri of the human parietal lobe: Volumes, spatial extents, automatic labelling, and probabilistic atlases.

Accurately describing the anatomy of individual brains enables interlaboratory communication of functional and developmental studies and is crucial for possible surgical interventions. The human parietal lobe participates in multimodal sensory integration including language processing and also contains the primary somatosensory area. We describe detailed protocols to subdivide the parietal lobe, analyze morphological and volumetric characteristics, and create probabilistic atlases in MNI152 stereotaxic space.

Complementary cortical gray and white matter developmental patterns in healthy, preterm neonates.

Preterm birth is associated with brain injury and altered cognitive development. However, the consequences of extrauterine development are not clearly distinguished from perinatal brain injury. Therefore, we characterized cortical growth patterns from 30 to 46 postmenstrual weeks (PMW) in 27 preterm neonates (25-32 PMW at birth) without detectable brain injury on magnetic resonance imaging.

Folding, But Not Surface Area Expansion, Is Associated with Cellular Morphological Maturation in the Fetal Cerebral Cortex.

Altered macroscopic anatomical characteristics of the cerebral cortex have been identified in individuals affected by various neurodevelopmental disorders. However, the cellular developmental mechanisms that give rise to these abnormalities are not understood. Previously, advances in image reconstruction of diffusion magnetic resonance imaging (MRI) have made possible high-resolution measurements of water diffusion anisotropy in the fetal brain.

3D in utero quantification of T2* relaxation times in human fetal brain tissues for age optimized structural and functional MRI.

Purpose: Maximization of the blood oxygen level-dependent (BOLD) functional MRI (fMRI) contrast requires the echo time of the MR sequence to match the T2* value of the tissue of interest, which is expected to be higher in the fetal brain compared with the brain of a child or an adult.

Methods: T2* values of the cortical plate/cortical gray matter tissue in utero in healthy fetuses from mid-gestation onward (20-36 gestational weeks) were measured using 3D T2* maps calculated from 2D dual-echo T2*-weighted data corrected for between-slice motion and reconstructed in 1.0 mm isotropic resolution from a sequence of multiple time points, together with 1.

Detecting default mode networks in utero by integrated 4D fMRI reconstruction and analysis.

Recently, there has been considerable interest, especially for in utero imaging, in the detection of functional connectivity in subjects whose motion cannot be controlled while in the MRI scanner. These cases require two advances over current studies: (1) multiecho acquisitions and (2) post processing and reconstruction that can deal with significant between slice motion during multislice protocols to allow for the ability to detect temporal correlations introduced by spatial scattering of slices into account. This article focuses on the estimation of a spatially and temporally regular time series from motion scattered slices of multiecho fMRI datasets using a full four-dimensional (4D) iterative image reconstruction framework.

Smaller Cerebellar Growth and Poorer Neurodevelopmental Outcomes in Very Preterm Infants Exposed to Neonatal Morphine.

Objective: To examine the relationship between morphine exposure and growth of the cerebellum and cerebrum in very preterm neonates from early in life to term-equivalent age, as well as to examine morphine exposure and brain volumes in relation to neurodevelopmental outcomes at 18 months corrected age (CA).

Study Design: A prospective cohort of 136 very preterm neonates (24-32 weeks gestational age) was serially scanned with magnetic resonance imaging near birth and at term-equivalent age for volumetric measurements of the cerebellum and cerebrum. Motor outcomes were assessed with the Peabody Developmental Motor Scales, Second Edition and cognitive outcomes with the Bayley Scales of Infant and Toddler Development, Third Edition at 18 months CA.

Patch-based augmentation of Expectation-Maximization for brain MRI tissue segmentation at arbitrary age after premature birth.

Accurate automated tissue segmentation of premature neonatal magnetic resonance images is a crucial task for quantification of brain injury and its impact on early postnatal growth and later cognitive development. In such studies it is common for scans to be acquired shortly after birth or later during the hospital stay and therefore occur at arbitrary gestational ages during a period of rapid developmental change. It is important to be able to segment any of these scans with comparable accuracy.

Characterization of Laminar Zones in the Mid-Gestation Primate Brain with Magnetic Resonance Imaging and Histological Methods.

Distinct populations of progenitor and postmitotic neural and glial cells are stratified in the fetal primate brain across developmentally transient tissue zones between the ventricular and pial surfaces. These zones were originally identified by light microscopy. However, it has subsequently been shown that various forms of magnetic resonance image (MRI) contrast can be used to distinguish layers of developing neural tissue in ex vivo, as well as in vivo (including in utero) conditions.

Mapping the developing human brain in utero using quantitative MR imaging techniques.

Magnetic resonance imaging of the human fetal brain has been a clinical tool for many years and provides valuable additional information to compliment more common ultrasound studies. Advances in both MRI acquisition and post processing over the last 10 years have enabled full 3D imaging and the accurate combination of data acquired in different head positions to create improved geometric integrity, tissue contrast, and resolution. This research is now motivating the development of new quantitative MRI-based techniques for clinical imaging that can more accurately characterize brain development and detect abnormalities.

Systemic glycerol decreases neonatal rabbit brain and cerebellar growth independent of intraventricular hemorrhage.

Background: Cerebellar hypoplasia is a common problem in preterm infants and infants suffering from intraventricular hemorrhage (IVH). To evaluate the effects of IVH on cerebellar growth and development, we used a neonatal rabbit model of systemic glycerol to produce IVH.

Methods: New Zealand White rabbit kits were surgically delivered 2 d preterm and treated with intraperitoneal glycerol (3.

On high-resolution image estimation using low-resolution brain MRI.

In the context of medical imaging, super-resolution (SR) is currently a promising post-processing technique to increase the image resolution. However, although many SR methods have been proposed in the literature, the gain of this type of approach in a real situation has not been precisely quantified. In this work, we evaluate image acquisition protocols and SR algorithms using in-vivo brain MR data as gold standard.

Adapting parcellation schemes to study fetal brain connectivity in serial imaging studies.

A crucial step in studying brain connectivity is the definition of the Regions Of Interest (ROI's) which are considered as nodes of a network graph. These ROI's identified in structural imaging reflect consistent functional regions in the anatomies being compared. However in serial studies of the developing fetal brain such functional and associated structural markers are not consistently present over time.