Organization of interlaminar interactions in the rat superior colliculus.
Organization of interlaminar interactions in the rat superior colliculus.
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DOI：
10.1152/jn.01051.2004
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发表时间：
2005-05
影响因子：
2.5
通讯作者：
Yasuhiko Saito;T. Isa
中科院分区：
文献类型：
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作者：
Yasuhiko Saito;T. Isa
我们之前的研究表明，当大鼠上丘（SC）切片暴露于含有10微米双丘碱和低浓度Mg2+ (0.1 mM)的溶液中时，大多数神经元位于中间灰色层（SGI层），宽视场垂直（WFV）细胞位于视神经层（SO层），少量神经元位于浅灰色层(浅灰质层；SGS)表现出自发去极化和突发放电，相邻神经元之间是同步的。这些自发和同步的去极化被认为与SGI神经元的前额叶爆发活动有共同的机制。在本研究中，我们通过在不同切片条件下进行双全细胞记录，探索了SGI神经元同步去极化产生的位点。从SC切片中取出的SGI小矩形片上记录的一对SGI神经元显示出同步去极化，但频率远低于包括SGS和SO在内的小矩形片上记录的频率。这表明浅层需要触发SGI的同步去极化。此外，我们记录了属于不同层的成对神经元的自发去极化。对其同步性的分析表明，大网膜下腔内的WFV细胞与SGS和SGI神经元均表现出同步去极化，且WFV细胞自发去极化的发生先于其他层的神经元。此外，当SGS和SGI神经元出现同步去极化时，SGI神经元通常先于SGS神经元。这些观察结果进一步证明了SC浅层和深层之间存在层间相互作用。此外，研究表明，WFV细胞可以触发SC其他层的爆发活动，并且存在从深层到浅层的兴奋信号传递。
Our previous studies have shown that when slices of the rat superior colliculus (SC) are exposed to a solution containing 10 microM bicuculline and a low concentration of Mg2+ (0.1 mM), most neurons in the intermediate gray layer (stratum griseum intermediale; SGI), wide-field vertical (WFV) cells in the optic layer (stratum opticum; SO), and a minor population of neurons in the superficial gray layer (stratum griseum superficiale; SGS) exhibit spontaneous depolarization and burst firing, which are synchronous among adjacent neurons. These spontaneous and synchronous depolarizations were thought to share common mechanisms with presaccadic burst activity in SGI neurons. In the present study, we explored the site responsible for generation of synchronous depolarization of SGI neurons by performing dual whole cell recordings under different slice conditions. A pair of SGI neurons recorded in a small rectangular piece of the SGI punched out from the SC slice showed synchronous depolarization but far less frequently than those recorded in a small rectangular piece including SGS and SO. This suggests that the superficial layers are needed for triggering synchronous depolarization in the SGI. Furthermore, we recorded spontaneous depolarizations in pairs of neurons belonging to the different layers. Analysis of their synchronicity revealed that WFV cells in the SO exhibit synchronous depolarizations with both SGS and SGI neurons, and the onset of spontaneous depolarization in WFV cells precedes those of neurons in other layers. Further, when SGS and SGI neurons exhibit synchronous depolarizations, SGI neurons usually precede the SGS neurons. These observations give further evidence to the existence of interlaminar interaction between superficial and deeper layers of the SC. In addition, it is suggested that WFV cells can trigger burst activity in other layers of the SC and that there is an excitatory signal transmission from the deeper layers to the superficial layers.