Departments of Paediatrics, Pathology and Laboratory Medicine (Neuropathology), and Clinical Neurosciences, University of Calgary Cumming School of Medicine and Alberta Children's Hospital Research Institute (Owerko Centre), Calgary, Alberta, Canada.
Pediatr Neurol. 2021 Oct;123:86-101. doi: 10.1016/j.pediatrneurol.2021.07.003. Epub 2021 Jul 10.
As with many body organs, the human central nervous system contains many structures and cavities that may have had functions in embryonic and fetal life but are vestigial or atrophic at maturity. Examples are the septum pellucidum, remnants of the lamina terminalis, Cajal-Retzius neurons, induseum griseum, habenula, and accessory olfactory bulb. Other structures are transitory in fetal or early postnatal life, disappearing from the mature brain. Examples are the neural crest, subpial granular glial layer of Brun over cerebral cortex, radial glial cells, and subplate zone of cerebral cortex. At times persistent fetal structures that do not regress may cause neurological problems or indicate a pathologic condition, such as Blake pouch cyst. Transitory structures thus can become vestigial. Examples are an excessively wide cavum septi pellucidi, suprapineal recess of the third ventricle, trigeminal artery of the posterior fossa circulation, and hyaloid ocular artery. Arrested maturation might be considered another aspect of vestigial structure. An example is the persistent microcolumnar cortical architecture in focal cortical dysplasia type Ia, in cortical zones of chronic fetal ischemia, and in some metabolic/genetic congenital encephalopathies. Some transitory structures in human brain are normal adult structures in lower vertebrates. Recognition of transitory and vestigial structures by fetal or postnatal neuroimaging and neuropathologically enables better understanding of cerebral ontogenesis and avoids misinterpretations.
与许多身体器官一样，人类中枢神经系统包含许多结构和腔室，这些结构和腔室在胚胎和胎儿期可能具有功能，但在成熟时则是退化的或萎缩的。例如，透明隔，终板的残余物，Cajal-Retzius 神经元，灰结节，缰核和副嗅球。其他结构在胎儿期或出生后早期是短暂存在的，会从成熟的大脑中消失。例如神经嵴，大脑皮质软脑膜下颗粒状胶质层，放射状胶质细胞和大脑皮质基板区。有时，持续存在的胎儿结构不会退化，可能会导致神经问题或表明存在病理状况，例如 Blake 袋囊肿。因此，暂时性结构可能会退化。例如，透明隔腔过大，第三脑室上隐窝，后循环颅底三叉动脉和玻璃状眼动脉。成熟受阻可能被认为是退化结构的另一个方面。例如，在局灶性皮质发育不良 Ia 型、皮质慢性胎儿缺血区和某些代谢/遗传先天性脑病中，持续存在的微小柱状皮质结构。人类大脑中的一些暂时性结构是低等脊椎动物的正常成年结构。通过胎儿或产后神经影像学和神经病理学识别暂时性和退化性结构，可以更好地理解大脑发生，并避免误解。
