Isochrony in the olivocerebellar system underlies complex spike synchrony.
Isochrony in the olivocerebellar system underlies complex spike synchrony.
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橄榄小脑系统中的等时性是复杂尖峰同步性的基础。
DOI：
10.1113/jphysiol.2006.571101
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
Sugihara,Izumi
中科院分区：
文献类型：
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作者：
Lang,EricJ;Llinás,Rodolfo;Sugihara,Izumi
在最近一期的生理学杂志中，Baker & Edgley（2006）发表了他们解释为大鼠橄榄小脑传导时间不均匀的结果。Baker和Edgley使用攀爬纤维反射来测量沿叶壁沿着不同点的传导时间。这种反射是由电刺激小脑白色物质引发的，其触发橄榄小脑轴突中的逆行尖峰，侵入下橄榄（IO）。由这些尖峰产生的电流通过电耦合IO神经元的差距连接传播到相邻的IO神经元（Llin ás等，1974）。这种扩散的兴奋可以触发顺向尖峰，这些尖峰返回到小脑皮层并触发浦肯野细胞复合体尖峰（CS）。Baker和Edgley发现攀爬纤维反射潜伏期随记录电极深度而变化，并由此推断IO和小脑皮质之间的传导时间随皮质位置而系统地变化。这项研究与我们和其他人的结果相冲突，这些结果表明大鼠和海龟的橄榄小脑传导时间几乎一致（Sugihara et al. 1993; Lang & Rosenbluth，2003; Ariel，2005）。下面我们将讨论这项新研究的几个令人不安的问题，但首先我们想指出，自发CS同步模式几乎需要统一的橄榄小脑传导时间。同步（毫秒时间尺度）CS活性已在几个物种中得到证实（Sasaki et al. 1989; Sugihara et al. 1993; Wylie et al. 1995; De Zeeuw et al. 1997; Lang et al. 1999;马歇尔et al. 2004）。虽然在许多研究中，记录只从尖部2a获得，橄榄小脑路径长度与所有细胞相似，因此传导速度不是主要问题，但在其他研究中，记录是从橄榄小脑路径长度几乎肯定不相同的区域进行的。例如，记录从顶2a和沿着其叶壁到2 mm的深度，显示在这些位置的细胞的CS之间发生显著水平的同步化（Sugihara et al. 1993）。最重要的是，
In a recent issue of The Journal of Physiology Baker & Edgley (2006) published results which they interpreted as showing a non-uniform olivocerebellar conduction time in the rat. Baker and Edgley used the climbing fibre reflex to measure conduction time to different points along a folial wall. This reflex is initiated by electrical stimulation of the cerebellar white matter, which triggers antidromic spikes in olivocerebellar axons that invade the inferior olive (IO). Current generated by these spikes spreads to neighbouring IO neurones via the gap junctions that electrically couple IO neurones (Llin ás et al. 1974). This spreading excitation can trigger orthodromic spikes that return to the cerebellar cortex and trigger Purkinje cell complex spikes (CSs). Baker and Edgley found that climbing fibre reflex latency varied with recording electrode depth, and inferred from this that conduction time between the IO and cerebellar cortex varies systematically with cortical location. This study conflicts with results by us and others that indicate a near uniform olivocerebellar conduction time in rats and turtles (Sugihara et al. 1993; Lang & Rosenbluth, 2003; Ariel, 2005). Below we discuss several troubling issues with this new study, but first we would like to make the point that spontaneous CS synchrony patterns almost necessitate a uniform olivocerebellar conduction time. Synchronous (on a millisecond time scale) CS activity has been demonstrated in several species (Sasaki et al. 1989; Sugihara et al.1993; Wylie et al. 1995; De Zeeuw et al. 1997; Lang et al. 1999; Marshall et al. 2004). Although in many studies recordings were obtained only from the apex of crus 2a, where the olivocerebellar path length is similar to all cells, and thus conduction velocity is not a major issue, in other studies, recordings were made from areas to which olivocerebellar path lengths almost certainly are not identical. For example, recordings from the apex of crus 2a and along its folial wall to a depth of 2 mm show that significant levels of synchronization occur between CSs of cells at these locations (Sugihara et al. 1993). Most importantly,