Croatian Institute for Brain Research, University of Zagreb School of Medicine, Salata 12, Zagreb, Croatia.
J Anat. 2010 Oct;217(4):400-17. doi: 10.1111/j.1469-7580.2010.01260.x.
The development of cortical axonal pathways in the human brain begins during the transition between the embryonic and fetal period, happens in a series of sequential events, and leads to the establishment of major long trajectories by the neonatal period. We have correlated histochemical markers (acetylcholinesterase (AChE) histochemistry, antibody against synaptic protein SNAP-25 (SNAP-25-immunoreactivity) and neurofilament 200) with the diffusion tensor imaging (DTI) database in order to make a reconstruction of the origin, growth pattern and termination of the pathways in the period between 8 and 34 postconceptual weeks (PCW). Histological sections revealed that the initial outgrowth and formation of joined trajectories of subcortico-frontal pathways (external capsule, cerebral stalk-internal capsule) and limbic bundles (fornix, stria terminalis, amygdaloid radiation) occur by 10 PCW. As early as 11 PCW, major afferent fibers invade the corticostriatal junction. At 13-14 PCW, axonal pathways from the thalamus and basal forebrain approach the deep moiety of the cortical plate, causing the first lamination. The period between 15 and 18 PCW is dominated by elaboration of the periventricular crossroads, sagittal strata and spread of fibers in the subplate and marginal zone. Tracing of fibers in the subplate with DTI is unsuccessful due to the isotropy of this zone. Penetration of the cortical plate occurs after 24-26 PCW. In conclusion, frontal axonal pathways form the periventricular crossroads, sagittal strata and 'waiting' compartments during the path-finding and penetration of the cortical plate. Histochemistry is advantageous in the demonstration of a growth pattern, whereas DTI is unique for demonstrating axonal trajectories. The complexity of fibers is the biological substrate of selective vulnerability of the fetal white matter.
人类大脑皮质轴突通路的发育始于胚胎期到胎儿期的过渡阶段，以一系列连续事件的形式发生，并在新生儿期导致主要长轨迹的建立。我们将组织化学标志物（乙酰胆碱酯酶（AChE）组织化学、突触蛋白 SNAP-25（SNAP-25-免疫反应性）抗体和神经丝 200）与扩散张量成像（DTI）数据库相关联，以便在 8 至 34 个孕周（PCW）之间重建通路的起源、生长模式和终止。组织学切片显示，皮质下-额通路（外囊、大脑干-内囊）和边缘束（穹窿、终纹、杏仁辐射）的最初生长和连接轨迹的形成发生在 10 PCW。早在 11 PCW，主要传入纤维就侵入皮质纹状体交界处。在 13-14 PCW，来自丘脑和基底前脑的轴突通路接近皮质板的深部部分，导致第一次分层。15 至 18 PCW 期间，主要是侧脑室交叉处、矢状层和基板及边缘带中的纤维的复杂化。由于该区域的各向同性，用 DTI 追踪基板中的纤维是不成功的。皮质板的穿透发生在 24-26 PCW 之后。总之，额叶轴突通路在皮质板的寻径和穿透过程中形成侧脑室交叉处、矢状层和“等待”室。组织化学在展示生长模式方面具有优势，而 DTI 则是展示轴突轨迹的独特方法。纤维的复杂性是胎儿白质选择性脆弱性的生物学基础。
