The alignment of serial sections by spatial filtering

Abstract

Studies of neural structure are limited by the difficulty of finding continuations of structures which extend beyond a single histological section. A method is presented which achieves the alignment of serial sections by using features appearing at the adjacent surfaces. The method should be applicable both in light and electron microscopy. We have applied and tested the method with 100-μm sections of cortical tissue stained by the rapid Golgi method. Here the measured features are constellations of points, the crossings of fibers through the plane of the cut. The first step requires a rough alignment using easily recognizable gross structures. In this way corresponding areas are determined. The precise alignment and identification of matching fibers is achieved by the method of matched filtering described by Vander Lugt. An example is presented and the significance of each stage in the alignment process is discussed.