Altman J, Bayer S A
Department of Biological Sciences, Purdue University, West Lafayette, IN 47907.
J Comp Neurol. 1988 Sep 15;275(3):406-28. doi: 10.1002/cne.902750306.
Short-survival, sequential, and long-survival thymidine radiograms of rat embryos, fetuses, and young pups were analyzed in order to examine the time of origin, settling pattern, migratory route, and site of origin of neurons of the reticular nuclear complex of the thalamus. On the basis of its chrono-architectonics, the reticular nucleus was divided into a central, medial, and lateral subnucleus. The central subnucleus is the earliest produced component of the entire thalamus with over 50% of its neurons being generated on day E13 and another 40% on day E14. Peak production of neurons of the lateral and medial subnuclei is on day E14. There is a lateral (earlier) to medial (later) neurogenetic gradient between these two components of the reticular complex: only about 12% of the lateral subnucleus neurons, but close to 30% of the medial subnucleus neurons, are generated on day E15. Because the lateral and medial subnuclei display the typical outside-in gradient found in the thalamus, they are considered to constitute a single cytogenetic sector; the early generated central subnucleus, which violates this order, is considered to constitute a separate cytogenetic sector. Observations are presented that neurons of the central reticular subnucleus originate in a unique neuroepithelial region, the reticular protuberance. The migration of heavily labeled cells was traced from this region in rats labeled with 3H-thymidine on day E13 and killed on the subsequent days. The neurons of the lateral and medial reticular subnuclei originate in the reticular lobule of the thalamic neuroepithelium. The migration of heavily labeled, spindle-shaped cells was traced from this region in rats labeled with 3H-thymidine on days E14 and E15 and killed at daily intervals thereafter. The neurogenetic gradient of the reticular thalamic complex seen in postnatal rats is established before birth.
为了研究丘脑网状核复合体神经元的起源时间、定居模式、迁移途径和起源部位，对大鼠胚胎、胎儿和幼崽的短期存活、连续和长期存活的胸苷放射自显影片进行了分析。根据其时间建筑学，网状核被分为中央、内侧和外侧亚核。中央亚核是整个丘脑最早产生的成分，其超过50%的神经元在胚胎第13天产生，另外40%在胚胎第14天产生。外侧和内侧亚核神经元的产生高峰在胚胎第14天。在网状复合体的这两个成分之间存在从外侧（较早）到内侧（较晚）的神经发生梯度：外侧亚核神经元只有约12%在胚胎第15天产生，而内侧亚核神经元接近30%在胚胎第15天产生。由于外侧和内侧亚核呈现出丘脑中典型的由外向内梯度，它们被认为构成一个单一的细胞遗传学区域；而早期产生的中央亚核违反了这一顺序，被认为构成一个单独的细胞遗传学区域。研究结果表明，中央网状亚核的神经元起源于一个独特的神经上皮区域，即网状隆起。在胚胎第13天用3H-胸苷标记并在随后几天处死的大鼠中，追踪了来自该区域的大量标记细胞的迁移。外侧和内侧网状亚核的神经元起源于丘脑神经上皮的网状小叶。在胚胎第14天和第15天用3H-胸苷标记并此后每天处死的大鼠中，追踪了来自该区域的大量标记的梭形细胞的迁移。出生后大鼠中所见的丘脑网状复合体的神经发生梯度在出生前就已确立。
