An iconometrographic representation of the growth of the central nervous system in man

Grenell, R. G.; Scammon, Richard E.

doi:10.1002/cne.900790302

Cited by 9 publications

(5 citation statements)

References 19 publications

(4 reference statements)

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“…After CS20, the growth of the prosencephalon becomes much greater than that of the other 2 sections, as the cerebral hemispheres grow rapidly, contributing to the exponential growth of the brain observed during the fetal period. The rate of growth of the prosencephalon continues to be greater than that of the rest of the brain throughout the fetal period and into postnatal development and adulthood (Dunn, 1921;Jenkins, 1921;Grenell and Scammon, 1943).…”

Section: Discussionmentioning

confidence: 98%

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Morphology and morphometry of the human embryonic brain: A three-dimensional analysis

et al. 2015

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The three-dimensional dynamics and morphology of the human embryonic brain have not been previously analyzed using modern imaging techniques. The morphogenesis of the cerebral vesicles and ventricles was analyzed using images derived from human embryo specimens from the Kyoto Collection, which were acquired with a magnetic resonance microscope equipped with a 2.35-T superconducting magnet. A total of 101 embryos between Carnegie stages (CS) 13 and 23, without apparent morphological damage or torsion in the brain ventricles and axes, were studied. To estimate the uneven development of the cerebral vesicles, the volumes of the whole embryo and brain, prosencephalon, mesencephalon, and rhombencephalon with their respective ventricles were measured using image analyzing Amira™ software. The brain volume, excluding the ventricles (brain tissue), was 1.15 ± 0.43 mm(3) (mean ± SD) at CS13 and increased exponentially to 189.10 ± 36.91 mm(3) at CS23, a 164.4-fold increase, which is consistent with the observed morphological changes. The mean volume of the prosencephalon was 0.26 ± 0.15 mm(3) at CS13. The volume increased exponentially until CS23, when it reached 110.99 ± 27.58 mm(3). The mean volumes of the mesencephalon and rhombencephalon were 0.20 ± 0.07 mm(3) and 0.69 ± 0.23 mm(3) at CS13, respectively; the volumes reached 21.86 ± 3.30 mm(3) and 56.45 ± 7.64 mm(3) at CS23, respectively. The ratio of the cerebellum to the rhombencephalon was approximately 7.2% at CS20, and increased to 12.8% at CS23. The ratio of the volume of the cerebral vesicles to that of the whole embryo remained nearly constant between CS15 and CS23 (11.6-15.5%). The non-uniform thickness of the brain tissue during development, which may indicate the differentiation of the brain, was visualized with surface color mapping by thickness. At CS23, the basal regions of the prosencephalon and rhombencephalon were thicker than the corresponding dorsal regions. The brain was further studied by the serial digital subtraction of layers of tissue from both the external and internal surfaces to visualize the core region (COR) of the thickening brain tissue. The COR, associated with the development of nuclei, became apparent after CS16; this was particularly visible in the prosencephalon. The anatomical positions of the COR were mostly consistent with the formation of the basal ganglia, thalamus, and pyramidal tract. This was confirmed through comparisons with serial histological sections of the human embryonic brain. The approach used in this study may be suitable as a convenient alternative method for estimating the development and differentiation of the neural ganglia and tracts. These findings contribute to a better understanding of brain and cerebral ventricle development.

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Section: Discussionmentioning

confidence: 98%

“…Most of the limited data available describe the initiation of fetal brain growth (Grenell and Scammon, 1943;Dunn, 1921). Jenkins (1921) measured the relative weight and volume of the component parts of the brain in 10 samples at different stages of development, including three samples from the embryonic period.…”

Section: Discussionmentioning

confidence: 99%

Morphology and morphometry of the human embryonic brain: A three-dimensional analysis

et al. 2015

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“…The fact that the forebrain grows fastest at the outset of brain growth most likely contributes to the fact that the human cerebrum is the largest among the vertebrates along with the odontocete whales and elephants (Pearson and Pearson,1976). Others have shown for the human fetus that growth of the forebrain is greater than for the rest of the brain (Dunn,1921,1926; Jenkins,1921; Grenell and Scammon,1943). Moreover, this growth trend holds true throughout the postnatal development until the adult‐sized brain is established (Hesdorffer and Scammon1935; Blinkov and Glezer,1968).…”

Section: Discussionmentioning

confidence: 99%

Expansion of the Human Embryonic Brain During Rapid Growth: Area Analysis

Levitan

Desmond

2009

The Anatomical Record

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This report focuses on growth of the brain of the early human embryo, Carnegie stages 12-23. Areas of median sections from 50 to 58 embryos were measured to determine the best mathematical model to describe growth of the three primary brain vesicles and to determine the change in the ratio of tissue to cavity areas (T/C). An exponential model best describes growth of the brain and head during this time period. The head expands 248-fold compared with a 171-fold growth of the brain. The whole brain, forebrain, and midbrain all exhibit larger cavities than tissue initially followed by a reversal of such at a critical time (stages 21-24). The presumptive cerebellar tissue which was twice the cavity initially grows to become more than six times the cavity. Boxplots of the T/C ratios for the head and brain plus its components reveal that initially the tissue is less than the cavity (10-20% and 40-60%, respectively) but eventually becomes larger Key words: growth parameters; brain expansion; mathematical models; CSF; cerebrospinal fluid pressure The brain and spinal cord or the central nervous system (CNS) first becomes apparent between the fourth and eighth weeks of development in the human (Desmond and O'Rahilly, 1981;O'Rahilly and Muller, 2006). Human embryology texts feature the elaborate changes in morphology that occur in the CNS during this time period but are remiss in conveying the tremendous growth of the embryonic CNS during these 4 weeks (Moore and Persaud, 2008a,b;Sadler, 2006). In fact, only one article exists in the literature to this day that documents such growth. This was a study reported more than 25 years ago by Desmond and O'Rahilly in which they measured the major axes of the three embryo brain vesicles. In that study, they compared the growth of the brain during the embryonic period, 4 to 8 weeks, with the fetal period, 8 weeks to birth. The study was limited to measuring one-dimensional lengths of the three major axes of the three embryo brain vesicles, namely, the bi-temporal (ear to ear) measurement, the frontal-occipital (forehead to back-of-head) measurement, and the dorsal-ventral (top-of-head to base) measurement. These findings, based on using one-dimensional axes, showed that the rates of growth of all three embryonic brain vesicles was much greater than the corresponding vesicles of the fetal period (Desmond and O'Rahilly, 1981).Interestingly, many of the current texts of human embryology draw attention to some of the more prominent abnormalities of the central nervous system such as hydrocephalus, spina bifida, and the Chiari type II malformation (Moore and Persaud, 2008a,b;Sadler, 2006). These same texts make no mention of the growth of the CNS and how mechanisms of growth might well play a role in these malformations.

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“…Previous studies (Desmond & O'Rahilly, 1981;Dunn, 1921;Grenell & Scammon, 1943;Levitan & Desmond, 2009) landmarks located at the different sections was erroneous. The mid-sagittal section was often selected as the only section to determine orientation for a given embryo.…”

Section: Comparison With Mri and Histological Studiesmentioning

confidence: 96%

“…As morphometry and quantitative analyses were previously difficult following gross anatomy and histology, previous studies were limited to using the methods of gross observation, dissection, and histological sectioning to detect the development of representative structures in the foetal brain (Desmond & O'Rahilly, 1981;Dobbing & Sands, 1973;Dunn, 1921;Grenell & Scammon, 1943;His, 1897;Hochstetter, 1919;Jenkins, 1921;Lemire et al, 1975;Levitan & Desmond, 2009). The recent advent of MRI acquisition systems has enabled the acquisition of small samples at high resolution (Habas et al, 2010;Smith, 1999), and postmortem specimens scanned with MRI revealed the development of the foetal brain at high resolution.…”

Section: Introductionmentioning

confidence: 99%

Morphology and morphometry of the human early foetal brain: A three‐dimensional analysis

et al. 2021

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Morphometric analyses in the early foetal phase (9-13 postconceptional week) are critical for evaluating normal brain growth. In this study, we assessed sequential morphological and morphometric changes in the foetal brain during this period using high-resolution T1-weighted magnetic resonance imaging (MRI) scans from 21 samples preserved at Kyoto University. MRI sectional views (coronal, mid-sagittal, and horizontal sections) and 3D reconstructions of the whole brain revealed sequential changes in its external morphology and internal structures. The cerebrum's gross external view, lateral ventricle and choroid plexus, cerebral wall, basal ganglia and thalamus, and corpus callosum were assessed. The development of the cerebral cortex, white matter microstructure, and basal ganglia can be well-characterized using MRI scans. The insula became apparent and deeply impressed as brain growth progressed.A thick, densely packed cellular ventricular/subventricular zone and ganglionic eminence became apparent at high signal intensity. We detected the emergence of important landmarks which may be candidates in the subdivision processes during the early foetal period; the corpus callosum was first detected in the sample with crownrump length (CRL) 62 mm. A primary sulcus on the medial part of the cortex (cingulate sulcus) was observed in the sample with CRL 114 mm. In the cerebellum, the hemispheres, posterolateral fissure, union of the cerebellar halves, and definition of the vermis were observed in the sample with CRL 43.5 mm, alongside the appearance of a primary fissure in the sample with CRL 56 mm and the prepyramidal fissure in the sample with CRL 75 mm. The volumetric, linear, and angle measurements revealed the comprehensive and regional development, growth, and differentiation of brain structures during the early foetal phase. The early foetal period was neither morphologically nor morphometrically uniform. The cerebral proportion (length/height) and the angle of cerebrum to the standard line at the lateral view of the cerebrum, which may reflect the growth and C-shape formation of the cerebrum, may be a candidate for subdividing the early foetal period. Future precise analyses must establish a staging system for the brain during the early foetal period. This study provides insights into brain structure, allowing for a correlation with functional maturation and facilitating the early detection of brain damage and abnormal development. | 499TAKAKUWA eT Al.

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An iconometrographic representation of the growth of the central nervous system in man

Cited by 9 publications

References 19 publications

Morphology and morphometry of the human embryonic brain: A three-dimensional analysis

Morphology and morphometry of the human embryonic brain: A three-dimensional analysis

Expansion of the Human Embryonic Brain During Rapid Growth: Area Analysis

Morphology and morphometry of the human early foetal brain: A three‐dimensional analysis

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