Horizontal synaptic connections in monkey prefrontal cortex:: An in vitro electrophysiological study
Horizontal synaptic connections in monkey prefrontal cortex:: An in vitro electrophysiological study
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DOI：
10.1093/cercor/10.1.82
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发表时间：
2000-01-01
期刊：
影响因子：
3.7
通讯作者：
Lewis, DA
中科院分区：
文献类型：
--
作者：
González-Burgos, G;Barrionuevo, G;Lewis, DA
在猴背外侧前额叶皮层（PFC），长距离，水平取向的内在轴突侧支相互连接的颗粒层上的锥体神经元簇。为了研究这些长距离投射所介导的电生理反应，使用猴PFC的体外切片制备获得来自第3层锥体神经元的全细胞膜片钳记录。使用在体内示踪剂注射，我们发现，长距离的投影保存良好，在冠状面切割PFC切片。突触后电流诱发低强度电细胞外刺激连续施加到20-30个离散的网站位于2200 μ m横向记录的细胞。应用几个标准来区分单突触反应和多突触反应。长距离单突触连接由传导速度相对较慢（0.14 m/s）的纤维介导。兴奋性突触后电流（EPSC）诱发的刺激短或长距离的水平连接没有不同的动力学特性。大多数（77%）的35层PFC神经元的研究是单突触的长距离连接的目标。由长距离连接介导的EPSC的振幅与短距离EPSC相似甚至更大，这表明前者提供的兴奋性输入相对稳健。对于大多数神经元（87.5%），其中一个完整的单突触EPSC的多点刺激诱发，EPSC振幅作为刺激距离的函数记录的细胞表现出统计学上显着的峰值。峰之间的间距类似于在以前的解剖学研究中观察到的神经元互连簇之间的间距。结果表明，长距离兴奋性连接是猴PFC第3层突触通讯的重要内在通路。
In monkey dorsolateral prefrontal cortex (PFC), long-distance, horizontally oriented intrinsic axon collaterals interconnect clusters of pyramidal neurons in the supragranular layers. In order to study the electrophysiological responses mediated by these long-distance projections, an in vitro slice preparation of monkey PFC was used to obtain whole-cell patch clamp recordings from layer 3 pyramidal neurons. Using in vivo tracer injections, we found that long-distance projections were well preserved in PFC slices cut in the coronal plane. Postsynaptic currents were evoked by low-intensity electrical extracellular stimulation applied successively to 20-30 discrete sites located up to 2200 mu m lateral to the recorded cell. Several criteria were applied to discriminate between mono- and polysynaptic responses. Long-distance monosynaptic connections were mediated by fibers with relatively slow conduction velocity (0.14 m/s). Excitatory postsynaptic currents (EPSCs) evoked by stimulation of short- or long-distance horizontal connections did not differ in kinetic properties. The majority (77%) of the 35 layer 3 PFC neurons studied were monosynaptic targets of long-distance connections. EPSCs mediated by long-distance connections had amplitudes that were similar or even larger than short-distance EPSCs, suggesting that excitatory input provided by the former was relatively robust. For most neurons (87.5%) in which a full complement of monosynaptic EPSCs was evoked by multisite stimulation, the EPSC amplitude as a function of stimulation distance from the recorded cells exhibited statistically significant peaks. The spacing between peaks was similar to the spacing between interconnected clusters of neurons observed in previous anatomical studies. The results show that long-distance excitatory connections constitute a significant intrinsic pathway of synaptic communication in layer 3 of monkey PFC.