Post Mortem Image Analysis of Astrocytes of the Human Principal Olivary Nucleus Using Geometrical and Fractal Parameters

Based on their morphology, the most abundant cells within the nervous tissue of the central nervous system, astrocytes, can be divided into two types, protoplasmic astrocytes and fibrous astrocytes. A further analysis of the brain tissue with the preserved astrocytes from the human principal olivary nucleus, based on their morphological differences with age, is successfully performed in this paper. Moreover, the images of 294 astrocytes, 148 fibrous and 146 protoplasmic, from the principal olivary nucleus were used. Applied for the first time in astrocytes image analysis, the principal component analysis was used to find the most informative parameters among geometrical and fractal in each of the four predefined groups, i.e., categories, of the morphological measurements of astrocytes in the images. The proposed subsets representing different morphological features can be used to distinguish astrocyte subtypes and predict their changes during normal aging. The values of the adequated parameters in different subsets were compared between the fibrous and protoplasmic astrocytes and correlated with age. Significant differences (p < 0.05) between the two subtypes were found in four Euclidean and four monofractal parameters. In addition, significant correlations were found between selected parameters and the age of subjects. In the upcoming iterations of this procedure, possible refinement and upgrades are expected.