无尾两栖类蟾蜍和鸣禽锡嘴雀听觉中枢及其神经通赂的比较研究

A COMPARATIVE STUDY OF AUDITORY CENTRE AND NEURAL PATHWAY IN ANURA AMPHIBIA BUFO GARGARIZANS AND SONGBIRD COCCOTHRAUSTES COCCOTHRAUSTES

本研究采用HRP示踪技术对无尾两栖类蟾蜍（Bufogargarizans）和鸣禽锡嘴雀（Ooccothraustescoccothraustes）从外周到听觉中枢的通路逐级进行了追踪比较研究.结果表明（1）无尾两栖类内耳囊听觉神经纤维上行投射到延髓同侧的背侧前庭核，它是听觉上行通路的第一级中枢，由此核中继后再投射到上橄榄核．以对侧为主；上橄榄核再发出纤维投射到中脑同侧的半环隆枕，后者是第三级中枢，此结果说明：无尾两栖类从外周到中脑听觉中枢的神经通路已较完整地形成；（2）鸣禽锡嘴雀的耳蜗听神经上行投射到听觉通路的第一级中队即延脑同侧的前庭外则核和角核，角核又发出纤维通过外侧丘系直接投射到对侧的中脑背外侧核．说明鸣禽鸟除了具备两栖类的听觉中枢及神经通路外．已进化形成独特的听觉神经通路即延脑的角核至中脑的背外侧核。

The auditory centre and neural Pathway from peripheral receptor to mesencephalicus in anura amphibia bufo gargarizansand songbird hawfinch were studied compariatively by horseradish peroxidase (HRP) transport method. The result indicated: (1) Auditory centre and pathway in anura amphibia bufo gargarizans: peripheral acoustic nerve fibers project ipsilaterallyto dorsal medullary nucleus (DMN). DMN is the first centre. The DMN projects to superior olivary nucleus (OS). mainly on theopposite side, OS is the second centre. then OS again send fibers and projects ipsilaterally to torus semicircularis (TS) of mesencephalon,TS is the third centre. The auditory noural pathway from peripheral receptor to mesencephalon have been formed.(2) Auditory centre and pathway in songbird: peripheral acoustic nerve fibers project and terminate ipsilaterally onto nucleus angularis (NA) and nucleus magnocellularis (NM). NA send fibers via lemniscus lateralis (LL) to nucleus mesencephalicus lateralis pars dorsalis (MLD), the projection is contralateral. Besides auditory centre and pathway comparable to anura amphibia.songbird has formed direct auditory pathway of brainstem.