Rouiller E M, Welker E
Institute of Physiology, University of Fribourg, Switzerland.
Hear Res. 1991 Nov;56(1-2):179-90. doi: 10.1016/0378-5955(91)90168-9.
Phaseolus vulgaris-leucoagglutinin (PHA-L) injection in the auditory cortex of the rat labeled anterogradely corticothalamic axons whose trajectory, morphology of terminals and their distribution were analyzed in light microscopy. From the primary auditory cortex, corticofugal axons ran in a rostral direction in the white matter (external capsule), and reached the internal capsule by crossing the caudate putamen. Then, they turned caudally, crossed the reticular nucleus (RE) of the thalamus, where some of them were seen to give off collaterals, ramifying in the 'auditory sector' of RE. From RE, the parent corticofugal axons continued in a caudal and medial direction to enter in the medial geniculate body (MGB). Corticofugal axons from the auditory cortex gave rise to 2 distinct types of terminals in the thalamus. First, small boutons (about 1 micron in diameter) were observed in the ventral division of the MGB (v-MGB; the main auditory relay nucleus in the thalamus), in RE, in the lateral part of the posterior thalamic nucleus, in the dorsal division of the MGB (d-MGB), as well as occasionally in the medial division of the MGB. Giant terminals (5-10 microns in diameter) formed the second type of cortical terminals, only present in a restricted zone of the ventral portion of d-MGB. Both types of terminals were observed as boutons 'terminaux' and 'en passant'. The zone of termination in v-MGB and RE varied as a function of the site of cortical injection. The similarity in the morphology and distribution of the terminals of corticothalamic axons arising from the primary auditory cortex with those of the primary somatosensory cortex of the mouse is striking and points to the existence of a basic pattern of connectivity used in corticothalamic processing of sensory information in rodents.
将菜豆白细胞凝集素（PHA-L）注入大鼠听觉皮层，可对皮质丘脑轴突进行顺行标记，通过光学显微镜分析其轨迹、终末形态及其分布。来自初级听觉皮层的皮质离心轴突在白质（外囊）中向嘴侧走行，穿过尾壳核后到达内囊。然后，它们转向尾侧，穿过丘脑网状核（RE），其中一些轴突在此发出分支，在RE的“听觉区”分支。从RE开始，母皮质离心轴突继续向尾侧和内侧走行，进入内侧膝状体（MGB）。来自听觉皮层的皮质离心轴突在丘脑中产生两种不同类型的终末。首先，在MGB腹侧部（v-MGB；丘脑中主要的听觉中继核）、RE、丘脑后核外侧部、MGB背侧部（d-MGB）以及偶尔在MGB内侧部观察到小终扣（直径约1微米）。巨大终末（直径5-10微米）形成了第二种皮质终末类型，仅存在于d-MGB腹侧部分的一个受限区域。两种类型的终末均观察到为“终末扣”和“旁支扣”。v-MGB和RE中的终末区域随皮质注射部位而变化。初级听觉皮层产生的皮质丘脑轴突终末的形态和分布与小鼠初级体感皮层的终末相似，这一点很显著，表明在啮齿动物感觉信息的皮质丘脑处理中存在一种基本的连接模式。
