Aims: 

Some interneurons in the dorsal cochlear nucleus (DCN) are similar and may be confused with each other, a quantitative approach has been employed in the present study to characterize and compare the morphological features of the pyramidal and giant cells of the rat DCN.

Methods: 

The neurons were labeled with biocytin. The cells were visualized using Alexa Fluor 488, and serial images were taken using confocal microscopy. The neurons were three-dimensionally reconstructed by the Neurolucida software. According to their somatic and dendritic appearances, the cells were either classified as giant or pyramidal neurons or a third, "unclassified" cell population. Two sets of quantitative variables were used on each reconstructed neuron to describe the soma, stem dendrites and the size and extension of the dendritic trees.

Results: 

The pyramidal cells presented more elongated cell bodies emerging thicker, longer and more complex dendritic trees than the other investigated neurones. In order to test whether the differences detected by univariate statistics are sufficient to unambiguous classification of DCN neurones, the variables were also subjected to multivariate discriminant analysis.

Conclusions: 

In the present study we concluded that the cell populations formed three fairly overlapping clusters according to their morphological variables and could be separated based on some quantitative variables. Our data also indicated that quantitative measurements with the combination of multivariate statistical analysis may give a useful method for classification of various projection neurons of the cochlear nucleus.