Grossmann R, Ellendorff F
Exp Brain Res. 1986;62(3):642-7. doi: 10.1007/BF00236044.
The present paper investigates the ontogeny of connective patterns in the brain of the 17-, 17.5-, and 18-day-old chicken embryo and in the newborn chicken as well. From the onset of electrical activity, neurophysiological properties of neurones undergo significant changes during further development. Total duration of action potentials decreases (p less than 0.001) between day 17 of incubation and day one of life. The percentage of spontaneously active neurones increases significantly (p less than 0.01) from 20% on day 17 to 69% in the newborn chick. For the same time period mean conduction velocity of presumed non-myelinated fibers in the hypothalamo-neurohypophysial-tract increases by about 50%. On the other hand, mean constant latency decreases from 20 ms in the 17-day-old embryo to 15.5 ms in the newborn chick (p less than 0.001). Changes in threshold intensity to antidromic stimulation and the increasing number of identifiable neurones per embryo indicate that new cell populations may become excitable during development. The results show, that considerable maturational events take place in action potential properties of the magnocellular system during late embryonal and early postnatal life of the chicken.
本文研究了17日龄、17.5日龄和18日龄鸡胚以及新生雏鸡大脑中连接模式的个体发生。从电活动开始，神经元的神经生理特性在进一步发育过程中会发生显著变化。在孵化第17天到出生后第1天期间，动作电位的总时长缩短（p<0.001）。自发活动神经元的百分比从第17天的20%显著增加（p<0.01）到新生雏鸡的69%。在同一时期，下丘脑 - 神经垂体束中假定的无髓鞘纤维的平均传导速度增加了约50%。另一方面，平均恒定潜伏期从17日龄胚胎的20毫秒降至新生雏鸡的15.5毫秒（p<0.001）。对逆向刺激的阈值强度变化以及每个胚胎中可识别神经元数量的增加表明，在发育过程中可能有新的细胞群体变得可兴奋。结果表明，在鸡胚胎后期和出生后早期，大细胞系统的动作电位特性发生了相当大的成熟事件。
