Morphology and cell classification of large neurons in the adult human dentate nucleus: A quantitative study

The dentate nucleus represents the most lateral of the four cerebellar nuclei that serve as a major relay centres for fibres coming from the cerebellar cortex. Although many relevant findings regarding to the three-dimensional structure, the neuronal morphology and the cytoarchitectural development of the dentate nucleus have been presented so far, very little quantitative information has been collected to further explain several types of large neurons in the dentate nucleus. In this study we quantified the morphology of the large dentate neurons in the adult human taking, into account seven morphometric parameters that describe the main properties of the cell soma, the dendritic field and the dendritic branching pattern. Since the lateral cerebellar nucleus in the cat and other lower mammals is homologous to the dentate nucleus in primates and man, we have classified our sample of large neurons in accordance with the shape of the cell body, the dendritic arborisation and their location within the dentate nucleus. By performing the appropriate statistical analysis, we have proved that our sample of human dentate neurons can be classified into four distinct types. In that sense, our quantitative analysis verifies the validity of previous qualitative conclusions concerning the large neurons in the developing human dentate nucleus. Furthermore, the present study represents the first attempt to perform a quantitative analysis and cell classification of the large projection neurons in the adult human dentate nucleus.