Shiraishi N, Katayama A, Nakashima T, Yamada S, Uwabe C, Kose K, Takakuwa T
Human Health Science, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Human Health Science, Graduate School of Medicine, Kyoto University, Kyoto, Japan; Congenital Anomaly Research Center, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Neuroimage. 2015 Jul 15;115:96-103. doi: 10.1016/j.neuroimage.2015.04.044. Epub 2015 Apr 28.
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.
此前尚未使用现代成像技术对人类胚胎大脑的三维动力学和形态进行分析。利用京都标本库中人类胚胎标本的图像，对脑泡和脑室的形态发生进行了分析，这些图像是通过配备2.35-T超导磁体的磁共振显微镜采集的。共研究了101个处于卡内基分期（CS）13至23期的胚胎，其脑室和轴没有明显的形态损伤或扭曲。为了评估脑泡发育的不均衡性，使用图像分析软件Amira™测量了整个胚胎和大脑、前脑、中脑、后脑及其各自脑室的体积。不包括脑室的脑体积（脑组织）在CS13期为1.15±0.43立方毫米（平均值±标准差），并在CS23期呈指数增长至189.10±36.91立方毫米，增长了164.4倍，这与观察到的形态变化一致。前脑的平均体积在CS13期为0.26±0.15立方毫米。该体积呈指数增长，直至CS23期达到110.99±27.58立方毫米。中脑和后脑的平均体积在CS13期分别为0.20±0.07立方毫米和0.69±0.23立方毫米；在CS23期分别达到21.86±3.30立方毫米和56.45±7.64立方毫米。小脑与后脑的比例在CS20期约为7.2%，在CS23期增至12.8%。脑泡体积与整个胚胎体积的比例在CS15至CS23期之间几乎保持恒定（11.6 - 15.5%）。发育过程中脑组织厚度的不均匀性可能表明大脑的分化，通过厚度表面颜色映射进行了可视化。在CS23期，前脑和后脑的基底区域比相应的背侧区域厚。通过从内外表面对组织层进行连续数字减法进一步研究大脑，以可视化增厚脑组织的核心区域（COR）。与核发育相关的COR在CS16期后变得明显；在前脑中尤其明显。COR的解剖位置大多与基底神经节、丘脑和锥体束的形成一致。通过与人类胚胎大脑的连续组织学切片比较得到了证实。本研究中使用的方法可能适合作为一种方便的替代方法，用于评估神经节和神经束的发育和分化。这些发现有助于更好地理解大脑和脑室的发育。
