Image co-registration

Image sequences of each mouse (as well as the brain mask for each mouse) were affine-transformed to a common atlas space determined by the positions of the junction between the coronal suture and sagittal suture (posterior to the olfactory bulb and cerebrum along midline) and lambda as we have done previously (60). Bregma was not visible in all mice and was calculated on the basis of the above two anatomical landmarks. The anterior-posterior stretch was set equal to the medial-lateral stretch, and all transformed images were centered at bregma. The intersection of every brain mask was calculated and made symmetric by reflection across the midline, allowing all subsequent comparisons to be performed on shared brain areas across all mice.