Assumption-Free Assessment of Corpus Callosum Shape: Benchmarking and Application

Figure 1

Overview of shape sources and methodology. Note. The figure depicts a visual summary of the analysis method undertaken in this study. Panel (a) depicts the source of shapes being studied: either simulated corpus callosum like contours (upper) or manual tracing from MRI data (lower). Panel (b) shows the outlines as denoted by x and y coordinates in two-dimensional space. Panel (c) shows how the outlines are operationalised by a series of elliptical Fourier harmonics, shown numerically (upper) and spatially (lower). Panel (d) depicts the original shape (upper), the same shape deconstructed and then recovered from elliptical Fourier harmonics (middle), and the measure of shape recovery (the overlap of these two shapes, the Jaccard index, lower). Panel (e) shows an array which demonstrates the systematic manipulation of simulated shapes on three axes, and panel (f) shows the relative position of those shapes in principal component space. Panel (g) depicts the information obtained from the principal components analysis undertaken in panel (f).