A quantitative approach to cytoarchitectonics: software and hardware aspects of a system for the evaluation and analysis of structural inhomogeneities in nervous tissue

Abstract

Cytoarchitectonic studies are based on the analysis of structural inhomogeneities in nervous tissue. Boundaries of brain regions are established where local structural properties such as numerical cell density, size, shape or orientation change. The measurement of these properties from histological sections with automatic devices is biased due to the thickness of the sections. In this study, the grey level index (GLI) is measured with a TV-based image analyzer from routine histological sections. This parameter is a biased estimate of the volume density of Nissl-positive structures. The histological section is digitized into GLI values by a computer-controlled scanning procedure. The result is stored in an image matrix which is processed by digital filtering in order to visualize the laminar pattern. GLI statistics of brain regions are evaluated from the pictorial data by delineating these regions with a cursor on a hard copy fixed to digitizer. Information from a series of sections is stored in a standardized data file and combined by specific application programs.