QUANTITATIVE GOLGI-STUDY OF THE RAT CEREBELLAR MOLECULAR LAYER INTERNEURONS USING PRINCIPAL COMPONENT ANALYSIS

In this study, we applied for the first time a multivariate analysis t o describe the anatomy of cerebellar molecular layer interneurons. For ty variables extending over a variety of morphological features (geome trical, topological, and metrical) were obtained from a three-dimensio nal reconstruction of 26 rat rapid Golgi-stained neurons. The subseque nt principal component analysis showed that the first principal compon ent was strongly correlated with variables related to the depth of eac h cell's soma in the molecular layer. The second principal component w as strongly correlated with parameters describing axonal morphology. F inally, an analysis of the distribution of these anatomical features s uggested that these cells cannot be classified into distinct groups bu t, instead, represent one continuously varying population. Thus, the c lassical division of molecular layer neurons into deep basket cells an d superficial stellate cells is not supported by our analysis. These r esults have important implications for the development of the cerebell ar cortex as well as for the expected patterns of Purkinje cell activi ty following activation of the granule cell layer. (C) 1998 Wiley-Liss , Inc.