MORPHOLOGY AND SPATIAL-DISTRIBUTION OF CORTICOTHALAMIC TERMINALS ORIGINATING FROM THE CAT AUDITORY-CORTEX
MORPHOLOGY AND SPATIAL-DISTRIBUTION OF CORTICOTHALAMIC TERMINALS ORIGINATING FROM THE CAT AUDITORY-CORTEX
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DOI：
10.1016/0378-5955(94)00199-z
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发表时间：
1995-03-01
期刊：
影响因子：
2.8
通讯作者：
DERIBAUPIERRE, F
中科院分区：
文献类型：
--
作者：
BAJO, VM;ROUILLER, EM;DERIBAUPIERRE, F
本文对猫听皮层起源的皮质丘脑轴突和终末的形态和空间分布进行了研究。在初级(AI)(N=2)、前(AAF)(N=1)、后(PAF)(N=1)和继发性(AII)(N=2)听野的电生理特征部位注射顺行示踪剂生物细胞素。听丘脑内可见两种不同类型的标记终末：小的球形终末(1~2微米)和巨大的指状终末(5~10微米)。在AI和AAF注射生物细胞素后，大多数顺行标记的轴突终止于内侧膝状体腹侧部(VMGB)外侧部头侧半部。在LV，皮质丘脑轴突大量分支，形成致密的终末区域，形成轮廓清晰的弧形条纹，末端小球状。在内侧膝状体内侧部(MMGB)可观察到由小末梢形成的附加终末区域。PAF投射位于内侧膝状体背侧支(DMGB)的背侧核(D)内，靠近vMGB的边界。PAF投射位于vMGB的尾侧半侧，在mMGB内仅见少量终末。在dMGB的浅部可见与背侧平行的皮质丘脑标记轴突发出的巨大终末。在dMGB的深背核(DD)内发现了一个由巨型终末和小终末组成的第二终末场。我们认为，小终末服务于向丘脑核的反馈投射，注入的皮质场从丘脑核接受其主要输入，而巨终末跨越平行上升听觉通路之间的边界。
In this paper we studied the morphology and spatial distribution of corticothalamic axons and terminals originating from the auditory cortical fields of the cat. The anterograde tracer biocytin was injected at electrophysiologically characterized loci in the primary (AI) (N = 2), anterior (AAF) (N = 1), posterior (PAF) (N = 1) and secondary (AII) (N = 2) auditory fields. In all cases, two different types of labeled terminals were found in the auditory thalamus: small spherical endings (1-2 mu m) and giant, finger-like endings (5-10 mu m).After biocytin injections in AI and AAF, the majority of anterogradely labeled axons terminated in the rostral half of the pars lateralis (LV) of the ventral division of the medial geniculate body (vMGB). In LV, the corticothalamic axons ramified profusely, giving rise to dense terminal fields forming well delineated curved stripes, with small spherical endings. Additional terminal fields formed by small endings were observed in the medial division of the medial geniculate body (mMGB). Giant endings were observed in a small area in the dorsal nucleus (D) of the dorsal division of the medial geniculate body (dMGB), near its border with the vMGB.PAF projections were located in the caudal half of vMGB and in mMGB, where only small terminals were found. Giant endings were seen in the superficial part of dMGB emerging from labeled corticothalamic axons oriented in parallel to the dorsal surface of the MGB. Projections from AII gave rise to a main terminal field of small endings in D; a second terminal field consisting of giant endings intermingled with small endings was found in the deep dorsal nucleus (DD) of dMGB.We conclude that small terminals serve the feedback projection to the thalamic nucleus from which the injected cortical field receives its main input, whereas giant terminals cross the borders between the parallel ascending auditory pathways.