A comparative cross sectional study of the morphological relationship between the superficial and deep gray matter structures in a random sample of cadaveric adult human brains in the Discipline of Clinical Anatomy at University of KwaZulu-Natal.

Abstract

Background: While various neurodegenerative diseases affect the cortical mass and mass of deep gray matter differently, finding an optimal and accurate method for measuring thickness and surface area of the cerebral cortex remains a challenging problem due to the highly convoluted surface of the cortex. We therefore investigated the superficial and deep gray matter thickness and surface area in a sample of cadaveric specimens at the Discipline of Clinical Anatomy, Nelson R Mandela School of Medicine, University of KwaZulu-Natal, South Africa to provide some clue as to possible variations in these parameters. Materials and Method: With ethical approval, 60 brain samples were uniformly sectioned at 5mm thickness and eight slices containing the deep nuclei were taken from each brain and stained by Mulligan’s technique. Thickness was measured at selected angles 0º, 45º, 90º, 135º and 180º for both right and left cerebral hemispheres. The cortical thickness and surface area of selected slices for both the superficial cortex and the corresponding deep nuclei were measured. Results: Mulligan’s stain produced good gray mater differentiation and clear images that enabled manual delineation of structures. There was rightward asymmetry of cortical thickness of the selected slices at the suggested angles which corresponded to structurally and functionally important brain regions. There was a positive correlation between the mean surface area of superficial cortex and deep nuclei across the regions of interest (ROI). Discussion and Conclusion: Baseline data from 55 brain samples provided a range of means and 95% confidence intervals for the three parameters of cortical thickness, cortical surface area and surface area of deep nuclei to be made for a reference table comprising eight coronal slices taken at five angles. This allows an objective assessment of thinning of the cortex or loss of deep gray matter to be made from measurements of the same parameters for the equivalent slices from a postmortem brain slice or an appropriate radiographic image.