Desmond N L, Levy W B
J Comp Neurol. 1982 Dec 1;212(2):131-45. doi: 10.1002/cne.902120204.
The granule cell dendritic fields of the adult rat dentate gyrus were analyzed quantitatively using a probabilistic method developed to correct dendritic length and segment number for dendrites cut during sectioning. Golgi-impregnated, linearized hippocampi were sectioned serially in one of the three hippocampal planes. Three dendritic field parameters were quantified from camera lucida drawings of these dendritic fields: dendritic field spread, dendritic length, and the branching and termination patterns of dendritic segments. Granule cell dendritic fields resembled cones, their maximal extent occurring in the distal third of the molecular layer. The ratio of transverse to longitudinal dendritic field spread was greater than 1:1 for the dorsal leaf and crest regions, but close to or less than 1:1 for the ventral leaf. The probabilities of segment branching and termination were highly similar for transversely and longitudinally sectioned tissue. The probability of branching varied among dendritic orders and across the molecular layer for the same order. The probability of termination did not vary greatly across orders. Most nonbranching segments terminated adjacent to the hippocampal fissure. On the average, a granule cell had 2.23 first-order dendrites that branched into a dendritic field containing seventh-order dendrites. Total dendritic length, corrected for cut dendrites and projection errors, averaged 3,662 +/- 88 microns. The somatic layer and proximal third of the molecular layer contained approximately 35% of this total length. The remainder, ca. 60%, was restricted to the distal two-thirds of the molecular layer, the predominant termination zone of perforant path axons. These data provide a quantitative characterization of the rat granule cell dendritic fields. Implementation of the probabilistic correction method overcomes methodological problems common to quantitative Golgi studies. These data permit a more precise relationship to be drawn between dendritic architecture and granule cell physiology.
采用一种为校正切片过程中被切断的树突的长度和节段数量而开发的概率方法，对成年大鼠齿状回的颗粒细胞树突场进行了定量分析。用高尔基染色法处理后的线性化海马体，在三个海马平面之一中进行连续切片。从这些树突场的明场绘图中量化了三个树突场参数：树突场扩展、树突长度以及树突节段的分支和终止模式。颗粒细胞树突场类似锥体，其最大范围出现在分子层的远端三分之一处。背叶和嵴区域横向与纵向树突场扩展的比率大于1:1，但腹叶的该比率接近或小于1:1。横向和纵向切片组织的节段分支和终止概率高度相似。分支概率在不同树突阶数之间以及同一阶数的分子层中各不相同。终止概率在不同阶数之间变化不大。大多数无分支节段在海马裂附近终止。平均而言，一个颗粒细胞有2.23个一级树突，这些树突分支形成一个包含七级树突的树突场。校正切断的树突和投影误差后的总树突长度平均为3662±88微米。体细胞层和分子层的近端三分之一包含该总长度的约35%。其余约60%局限于分子层的远端三分之二，即穿通通路轴突的主要终止区。这些数据提供了大鼠颗粒细胞树突场的定量特征。概率校正方法的实施克服了定量高尔基研究中常见的方法学问题。这些数据使得能够在树突结构与颗粒细胞生理学之间建立更精确的关系。
