Fig. 2. Atlas morphology: sizes and shapes.

| a, Volume distribution of atlas parcellations demonstrating the diversity of parcellation sizes. b, Parcellation sphericity distributions illustrating how the shapes of different parcellations may not be uniform. c, Volumes versus sphericity showing how some atlas parcellations may be small and spherical, while others may be large and non-spherical. This illustrates the non-uniformity in atlas parcellations. d, Volumes and sphericity of random atlases showing the uniformity of sphericity with changing volumes. Random atlases allow us to study (1) the effect of parcellation scale without the confound of shape effects and (2) the need for accurate anatomical boundaries to test a hypothesis about the structure–function relationship in the brain at seizure onset. Numbers in legend represent the number of parcellations for each random atlas. Remaining atlases are in Fig. S2.