Sawada Kazuhiko, Sun Xue-Zhi, Fukunishi Katsuhiro, Kashima Masatoshi, Sakata-Haga Hiromi, Tokado Hiroshi, Aoki Ichio, Fukui Yoshihiro
Laboratory of Anatomy, Department of Physical Therapy, Faculty of Medical and Health Sciences, Tsukuba International University, Tsuchiura, Ibaraki, 300-0051, Japan.
Brain Struct Funct. 2009 Sep;213(4-5):469-80. doi: 10.1007/s00429-009-0204-x. Epub 2009 Feb 12.
The aim of this study was to spatio-temporally clarify gross structural changes in the forebrain of cynomolgus monkey fetuses using 7-tesla magnetic resonance imaging (MRI). T(1)-weighted coronal, horizontal, and sagittal MR slices of fixed left cerebral hemispheres were obtained from one male fetus at embryonic days (EDs) 70-150. The timetable for fetal sulcation by MRI was in good agreement with that by gross observations, with a lag time of 10-30 days. A difference in detectability of some sulci seemed to be associated with the length, depth, width, and location of the sulci. Furthermore, MRI clarified the embryonic days of the emergence of the callosal (ED 70) and circular (ED 90) sulci, which remained unpredictable under gross observations. Also made visible by the present MRI were subcortical structures of the forebrain such as the caudate nucleus, globus pallidus, putamen, major subdivisions of the thalamus, and hippocampal formation. Their adult-like features were formed by ED 100, corresponding to the onset of a signal enhancement in the gray matter, which reflects neuronal maturation. The results reveal a highly reproducible level of gross structural changes in the forebrain using a high spatial 7-tesla MRI. The present MRI study clarified some changes that are difficult to demonstrate nondestructively using only gross observations, for example, the development of cerebral sulci located on the deep portions of the cortex, as well as cortical and subcortical neuronal maturation.
本研究的目的是利用7特斯拉磁共振成像（MRI），从时空角度阐明食蟹猴胎儿前脑的大体结构变化。从一只雄性胎儿的固定左脑半球获取了胚胎期（EDs）70 - 150天的T(1)加权冠状、水平和矢状位MR切片。通过MRI确定的胎儿脑沟形成时间表与大体观察结果高度一致，滞后时间为10 - 30天。某些脑沟的可检测性差异似乎与脑沟的长度、深度、宽度和位置有关。此外，MRI明确了胼胝体沟（胚胎期70天）和环状沟（胚胎期90天）出现的胚胎日，而在大体观察下这些是无法预测的。本研究的MRI还显示了前脑的皮质下结构，如尾状核、苍白球、壳核、丘脑的主要亚区和海马结构。它们类似成人的特征在胚胎期100天形成，这与灰质信号增强的开始相对应，灰质信号增强反映了神经元的成熟。结果表明，使用高空间分辨率的7特斯拉MRI可以高度重现前脑的大体结构变化。本MRI研究明确了一些仅通过大体观察难以无损显示的变化，例如位于皮质深部的脑沟发育以及皮质和皮质下神经元的成熟。
