Figure 1.

Composite images constructed from the MRI data for the supramarginal gyrus. (a) Masked areas are superimposed over anatomy in Freesurfer, on left. (b) Composite images constructed from layering many such masks are shown on the right. Each column shows the composite images of one sibling: the older sibling (OS) and the twins (TD Twin and Proband), respectively; rows represent the three anatomic axes. Images are semi-transparent such that brighter areas indicate higher volume areas—or more precisely, a brighter pixel is one that was present in a greater number of mask slices. Colorization is arbitrary and is used in masking to visually differentiate the mask from the underlying grayscale MRI image; grayscale versions were used in analysis.