Chevalier G, Deniau J M
Neuroscience. 1984 Jun;12(2):427-39. doi: 10.1016/0306-4522(84)90063-0.
The aim of the present study was to identify in the rat the diencephalic nuclei addressed by ascending collaterals of tecto-spinal neurons. For this purpose we made use of anterograde axonal transport method to determine the pattern of diencephalic projections arising from the lateral portion of the superior colliculus where most of tecto-spinal neurons are lying. Next, we used the antidromic activation method to analyse whether some of these colliculo-diencephalic projections were provided through collaterals of tecto-spinal neurons. Following injections of wheatgerm agglutinin, conjugated with horseradish peroxidase, in the lateral part of the superior colliculus, anterograde labelling was observed in: the contralateral superior colliculus, the ipsilateral pretectal nuclei, subthalamic area (zona incerta and Forel field) and thalamic structures namely: dorsal and ventral lateral geniculate, parafascicular, posterior nuclear group, reuniens nuclei and lateral portion of medio-dorsal nucleus. Moreover, bilateral projections were revealed in the following thalamic nuclei: lateral posterior, ventro-medial, paracentral and central-lateral. In the electrophysiological study we established that the thalamic nuclei medio-dorsal/central-lateral, paracentral, ventral-medial and the zona incerta receive ascending collaterals of the tecto-spinal neurons. In addition, an axonal branch to the contralateral superior colliculus was also revealed. The various ascending and descending collaterals of each branched neuron exhibited a similar conduction time for action potentials. It is thus likely that the tecto-spinal/tecto-diencephalic neurons provide a synchronized influence on their targets. The functional implication of such a branched collicular efferent pathway is discussed. Considering that tecto-spinal neurons are one of the collicular neuronal populations on which the substantia nigra exerts its influence, new perspectives in the analysis of basal ganglia collicular relationships are given.
本研究的目的是在大鼠中确定顶盖脊髓神经元的升支侧支所投射的间脑核团。为此，我们采用顺行轴突运输法来确定源自上丘外侧部分（大多数顶盖脊髓神经元所在部位）的间脑投射模式。接下来，我们使用逆向激活法来分析这些顶盖 - 间脑投射中是否有一些是通过顶盖脊髓神经元的侧支实现的。在上丘外侧部分注射与辣根过氧化物酶结合的小麦胚凝集素后，在以下部位观察到了顺行标记：对侧上丘、同侧顶盖前核、丘脑底区域（未定带和Forel区）以及丘脑结构，即：背侧和腹侧外侧膝状体、束旁核、后核群、连合核以及背内侧核的外侧部分。此外，在以下丘脑核团中发现了双侧投射：外侧后核、腹内侧核、中央旁核和中央外侧核。在电生理研究中我们确定，丘脑核团背内侧/中央外侧核、中央旁核、腹内侧核以及未定带接受顶盖脊髓神经元的升支侧支。此外，还发现了一条到对侧上丘的轴突分支。每个分支神经元的各种升支和降支侧支对动作电位表现出相似的传导时间。因此，顶盖脊髓/顶盖 - 间脑神经元很可能对其靶标提供同步影响。本文讨论了这种分支的顶盖传出通路的功能意义。鉴于顶盖脊髓神经元是黑质施加影响的顶盖神经元群体之一，本文还给出了基底神经节与顶盖关系分析的新视角。
