Plessinger M A, Woods J R
Am J Physiol. 1986 Jan;250(1 Pt 2):R137-41. doi: 10.1152/ajpregu.1986.250.1.R137.
Singleton fetuses from five pregnant ewes of 120-129 days gestation (term = 145 days) were tested for fetal auditory brain stem responses (ABR) generated by earphones placed on the maternal abdomen and compared with ABRs generated by an earphone secured in the fetal lamb's ear. To conduct these studies a cesarean section was performed on the pregnant ewe at 105-110 days gestation in order to implant stainless steel electrodes in the fetal scalp and a hearing aid receiver in the fetal external ear canal. The fetus was returned to the uterus, and the pregnancy was allowed to continue. Comparison of the externally elicited fetal ABR with the internally elicited fetal ABR indicates similar response patterns with delayed peak latencies observed in ABR responses from external stimulation. This new method of generating fetal ABRs by an external sound source documents the neurological response of the fetal auditory end organ and the fetal brain stem in the pregnant nonstressed animal model and may have applications in developmental studies of the fetal auditory system.
对妊娠120 - 129天（足月为145天）的五只怀孕母羊的单胎胎儿进行了测试，通过放置在母羊腹部的耳机产生胎儿听觉脑干反应（ABR），并与固定在胎羊耳朵中的耳机产生的ABR进行比较。为了进行这些研究，在妊娠105 - 110天时对怀孕母羊进行剖宫产，以便在胎儿头皮植入不锈钢电极，并在胎儿外耳道植入助听器接收器。将胎儿放回子宫，让妊娠继续。外部诱发的胎儿ABR与内部诱发的胎儿ABR的比较表明，反应模式相似，但外部刺激的ABR反应中观察到峰值潜伏期延迟。这种通过外部声源产生胎儿ABR的新方法记录了未受应激的怀孕动物模型中胎儿听觉终器和胎儿脑干的神经反应，可能在胎儿听觉系统的发育研究中有应用。
