Spruston N, Lübke J, Frotscher M
Max-Planck-Institut für medizinische Forschung, Abteilung Zellphysiologie, Heidelberg, Germany.
J Comp Neurol. 1997 Sep 1;385(3):427-40.
The anatomical and electrophysiological properties of neurons in the stratum lucidum of the CA3 subfield of the hippocampus were examined by using patch-pipette recordings combined with biocytin staining. This method facilitated the analysis of the morphological features and passive and active properties of a recently described class of spiny neurons in the stratum lucidum, as well as aspiny neurons in this region. Some, but not all, synaptic inputs of both types of neurons were found to arise from the mossy fiber system. The axons of spiny neurons in the stratum lucidum were heavily collateralized, terminating primarily in the stratum lucidum and stratum radiatum of CA3, and to a lesser extent in the stratum pyramidale and stratum oriens. Only a few axonal projections were found that extended beyond the CA3 region into CA1 and the hilus. Aspiny neurons fell into two classes: those projecting axons to the stratum lucidum and stratum radiatum of CA3 and those with axon terminations mainly in the stratum pyramidale and stratum oriens. The electrophysiological properties of spiny and aspiny neurons in the stratum lucidum were similar, but on average, the aspiny neurons had significantly higher maximal firing rates and narrower action potential half-widths. The results demonstrate that a diverse population of neurons exists in the region of mossy fiber termination in area CA3. These neurons may be involved in local-circuit feedback, or feed-forward systems controlling the flow of information through the hippocampus.
采用膜片钳记录结合生物胞素染色的方法，研究了海马CA3亚区透明层神经元的解剖学和电生理特性。该方法有助于分析透明层中最近描述的一类棘状神经元以及该区域的无棘神经元的形态特征、被动特性和主动特性。发现这两类神经元的部分（而非全部）突触输入来自苔藓纤维系统。透明层中棘状神经元的轴突有大量分支，主要终止于CA3的透明层和辐射层，较少终止于锥体层和原层。仅发现少数轴突投射延伸至CA3区域之外，进入CA1和海马齿状回。无棘神经元分为两类：一类将轴突投射到CA3的透明层和辐射层，另一类轴突主要终止于锥体层和原层。透明层中棘状和无棘神经元的电生理特性相似，但平均而言，无棘神经元的最大放电率显著更高，动作电位半宽度更窄。结果表明，在CA3区苔藓纤维终末区域存在多种神经元。这些神经元可能参与局部回路反馈或控制通过海马的信息流的前馈系统。
