Neural organization of the pathways from the superior colliculus to trochlear motoneurons
Neural organization of the pathways from the superior colliculus to trochlear motoneurons
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DOI：
10.1152/jn.01073.2006
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发表时间：
2007-05-01
影响因子：
2.5
通讯作者：
Shinoda, Yoshikazu
中科院分区：
文献类型：
--
作者：
Izawa, Yoshiko;Sugiuchi, Yuriko;Shinoda, Yoshikazu
使用细胞内记录和跨神经元标记技术对麻醉猫中从上丘 (SC) 到滑车运动神经元的通路的神经组织进行分析。刺激同侧或对侧 SC 会引起滑车运动神经元的兴奋和抑制，潜伏期分别为 1.1-2.3 和 1.1-3.8 ms，表明兴奋和抑制的最早组成部分是非突触的。两个 SC 之间的中线部分显示，同侧和对侧 SC 刺激分别引起滑车运动神经元的突触兴奋和抑制。将小麦胚芽凝集素缀合的辣根过氧化物酶应用到滑车神经后，进行跨神经元标记的前运动神经元主要分布在同侧的福雷尔视野 H (FFH) 和双侧的卡哈尔间质核 (INC)。因此，我们从电生理学角度研究了 SC 和滑车核之间的这两个可能的中介。刺激 FFH 会引起滑车运动神经元的同侧单突触和双突触兴奋以及对侧双突触抑制。同侧 SC 的预处理刺激有利于 FFH 诱发的单突触兴奋。刺激 INC 会引起滑车运动神经元的同侧单突触兴奋和抑制，以及对侧单突触抑制。对侧 SC 的预处理刺激促进了对侧 INC 诱发的单突触抑制。这些结果揭示了扫视系统中从 SC 到垂直眼部运动神经元的交互输入模式；滑车运动神经元通过同侧 FFH 神经元接收来自同侧 SC 的突触兴奋，并通过对侧 INC 神经元接收来自对侧 SC 的突触抑制。这些抑制性 INC 神经元被认为是水平扫视系统中抑制性爆发神经元的对应物。
The neural organization of the pathways from the superior colliculus (SC) to trochlear motoneurons was analyzed in anesthetized cats using intracellular recording and transneuronal labeling techniques. Stimulation of the ipsilateral or contralateral SC evoked excitation and inhibition in trochlear motoneurons with latencies of 1.1-2.3 and 1.1-3.8 ms, respectively, suggesting that the earliest components of excitation and inhibition were disynaptic. A midline section between the two SCs revealed that ipsi- and contralateral SC stimulation evoked disynaptic excitation and inhibition in trochlear motoneurons, respectively. Premotor neurons labeled transneuronally after application of wheat germ agglutinin-conjugated horseradish peroxidase into the trochlear nerve were mainly distributed ipsilaterally in the Forel's field H (FFH) and bilaterally in the interstitial nucleus of Cajal (INC). Consequently, we investigated these two likely intermediaries between the SC and trochlear nucleus electrophysiologically. Stimulation of the FFH evoked ipsilateral mono- and disynaptic excitation and contralateral disynaptic inhibition in trochlear motoneurons. Preconditioning stimulation of the ipsilateral SC facilitated FFH-evoked monosynaptic excitation. Stimulation of the INC evoked ipsilateral monosynaptic excitation and inhibition, and contralateral monosynaptic inhibition in trochlear motoneurons. Preconditioning stimulation of the contralateral SC facilitated contralateral INC-evoked monosynaptic inhibition. These results revealed a reciprocal input pattern from the SCs to vertical ocular motoneurons in the saccadic system; trochlear motoneurons received disynaptic excitation from the ipsilateral SC via ipsilateral FFH neurons and disynaptic inhibition from the contralateral SC via contralateral INC neurons. These inhibitory INC neurons were considered to be a counterpart of inhibitory burst neurons in the horizontal saccadic system.