Fig. 3: NextBrain probabilistic atlas.
From: A probabilistic histological atlas of the human brain for MRI segmentation
a, Comparison with whole brain atlases. Portions of the NextBrain probabilistic atlas (which has 333 ROIs), the SAMSEG atlas in FreeSurfer35 (13 ROIs) and the manual labels of MNI based on the Allen atlas3 (138 ROIs). b, Close-up of three orthogonal slices of NextBrain. The colour coding follows the convention of the Allen atlas3, where the hue indicates the structure (for example, purple is thalamus, violet is hippocampus, green is amygdala) and the saturation is proportional to neuronal density. The colour of each voxel is a weighted sum of the colour corresponding to the ROIs, weighted by the corresponding probabilities at that voxel. The red lines separate ROIs on the basis of the most probable label at each voxel, thus highlighting boundaries between ROIs of similar colour; we note that the jagged boundaries are a common discretization artefact of probabilistic atlases in regions where two or more labels mix continuously: for example, the two layers of the cerebellar cortex.
