鸽丘脑听觉中继核团传出神经投射的研究

EFFERENT PROJECTIONS OF THALAMICAL AUDITORY NUCLEI IN RING DOVE

应用神经示踪物生物素标记的葡聚糖胺对环鸽丘脑听觉中继核团的传出神经投射进行了研究。结果发现：（１）丘脑卵圆核的传出纤维投射至端脑新纹状体内侧的Ｌ２听区；（２）卵圆核壳的传出纤维投射至Ｌ１、Ｌ３和部分Ｌ２听区，在Ｌ区周围亦存在许多标记终末；（３）尾侧卵圆核壳的传出投射参与了卵圆核壳的形成并发出二束纤维分别投射至下丘脑腹内侧核和端脑新纹状体Ｌ区外侧的旁听区。本实验结果首次揭示在鸟类丘脑听中继核团、端脑新纹状体听区和与内分泌相关的下丘脑核团间存在一条直接联系的神经通路。

The efferent projections of the auditory thalamus in ring dove (Streptopelia risoria) were studied by using the antereograde method of biotinylated dextran amine(BDA). The results showed that: (1) Injection of BDA into n. ovoidalis of the ring dove produced mainly terminal labeling in the field L 2 of the auditory neostriatum; (2)Injections of BDA into the n. ovoidalis and its shell areas (Ov shell) resulted in labeling of terminals within field L 1, L 3 and part L 2 of neostriatum and some labeled terminals extended into the peripheral zones of field L; (3)Injection of BDA into the posterior portions of Ov shell(Ovp) produced dense labeling of fibers which formed Ov shell surrounding Ov and also caused labeling of two groups of efferent projections. One group of the labeled fibers entered the region of neostriatum (par L) which coursed closely parallel to adjacent field L; and the another group directly descended to the n. ventromedialis hypothalami (VMN). Our findings revealed for the first time that there are two direct pathways by which the auditory area of the neostriatum and the n. ventromedialis hypothalami related to the endocrinal function are connected to the auditory relay nuclei of the thalamus.