Topologic distribution of different types of neurons in the human putamen

To test the assumption that the various types of neuron in the human putamen appear to be randomly distributed and to quantify the way in which they are arranged, stochastic geometry, multivariate analysis and the interactive evaluation technique were employed.

Twenty-seven human putamina without demonstrable signs of neurologic change were dissected out, fixed in 4% formalin and embedded in paraffin. The 20-micron paraffin sections were stained in an aldehyde-fuchsin and cresyl-violet solution, which makes it possible to distinguish between seven different neuron populations in the putamen. The gravity centers, size and form factors of these neurons were determined morphometrically under a light microscope. The data obtained were used to calculate the spatial distribution of the neurons by interactive and structure analytical methods.

Visual point field analysis revealed an irregular arrangement of the different types of neurons. Point process analysis detected a significant hard core process of type 1 and a cluster process of type 6 neurons. With nearest neighborhood analysis, significant differences were found between certain populations of neurons and Poisson processes. Comparison of the results of multivariate cluster analysis with the investigator-dependent results of visual point field analysis showed clear differences.

By means of structure analytical methods, the arrangement of different populations of neurons can be demonstrated. Some neuronal distributions are detectable only by using one of these techniques. The question of random or nonrandom distribution of the neurons in the human putamen can now be answered definitively: arrangement of the different populations of neurons is structured.