PYRAMIDAL AND CORTICOSPINAL SYNAPTIC EFFECTS OVER RETICULOSPINAL NEURONS IN THE CAT
PYRAMIDAL AND CORTICOSPINAL SYNAPTIC EFFECTS OVER RETICULOSPINAL NEURONS IN THE CAT
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DOI：
10.1113/jphysiol.1993.sp019606
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发表时间：
1993-04-01
影响因子：
5.5
通讯作者：
LAMAS, JA
中科院分区：
文献类型：
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作者：
CANEDO, A;LAMAS, JA
1.用103个十字前神经元的自发活动(58个来自锥体束而不是来自皮质脊髓束(PTNS)；45个来自两个部位(CSNS))的自发活动来触发294个网状脊髓神经元(RSN)细胞内记录的突触噪声的平均值。这些RSNs在氯醛糖麻醉猫对侧球内侧网状结构(NRGc)的巨细胞网状核中被记录到。12个锥体束神经元(6个CSN)，26个(10个CSN)每个神经元2个RSN，30个(13个CSN)每个3个RSN，35个(16个CSN)每个4个RSN。在20个PTN和15个CSN产生的平均突触后电位中观察到。PTNS和CSNS对RSN的唯一突触效应是兴奋性的，在注入去极化或超极化电流后，所有受试者(n=15)的兴奋性突触后电位(EPSP)的幅度、形状或时程均未发现任何变化。这表明突触可能位于树突的远端。记录突触前峰可以将传导时间和突触延迟从总潜伏期中分离出来。根据我们的数据，在RSN上似乎存在两种不同类型的皮质分离神经元兴奋：PTNS和CSNS都产生的单突触效应和PTNS而不是CSNS产生的双突触效应。双突触EPSP的上升时间慢于单突触EPSP，宽度明显长于单突触EPSP。
1. The spontaneous activity of 103 precruciate neurones (fifty-eight activated antidromically from the pyramidal tract but not from the corticospinal tract, PTNs; forty-five activated from both sites, CSNs) was used to trigger the average of the intracellularly recorded synaptic noise in 294 reticulospinal neurones (RSNs). These RSNs were recorded in the nucleus reticularis gigantocellularis of the contralateral medial bulbar reticular formation (NRGc) in chloralose-anaesthetized cats.2. Twelve pyramidal tract neurones (six CSNs) were tested with a single RSN, twenty-six (10 CSNs) with two RSNs each, thirty (13 CSNs) with three RSNs each, and thirty-five (16 CSNs) with four RSNs each. Postsynaptic potentials were observed in the averages generated by twenty PTNs and fifteen CSNs.3. The only synaptic effect produced by both PTNs and CSNs upon RSNs in our sample was excitatory, and in none of the tested cases (n = 15) were any changes found in the amplitude, shape, or duration of the excitatory postsynaptic potentials (EPSPs) after injection of depolarizing or hyperpolarizing currents. This suggests that the synapses are probably located at the distal dendrites.4. Recording of the presynaptic spike allowed separation of the conduction time and synaptic delay from the total latency. According to our data there appear to be two different types of excitation of corticofugal neurones over RSNs: a monosynaptic effect produced by both PTNs and CSNs, and a disynaptic effect produced by PTNs but not by CSNs. The disynaptic EPSPs had statistically significant slower rise times and longer widths than the monosynaptic EPSPs.