The three structural modalities (Fig 1) provide information about different aspects of the brain’s tissues, structures and neuropathologies. Data quality at the single-subject level is illustrated in Fig 1a,b. The group-averaged images produced for each modality are included in the initial data release as high-quality atlases (Fig 1c-f), depicting strong tissue contrast and excellent fidelity of alignment across subjects. The T1 modality (Fig 1a,c) is the most informative about the basic structure of the brain, including the depiction of the main tissue types (gray and white matter) and gross structure of the brain (main anatomical landmarks). From the T1 data, we derived 25 volumetric IDPs: total tissue volumes (gray, white and ventricular cerebro-spinal fluid), and the volumes of subcortical gray matter structures such as thalamus, caudate, putamen, pallidum, hippocampus and amygdala. The T1 data and T1-derived IDPs provide sensitive markers of atrophy (tissue loss), which can be both global (e.g., thinning of the cortex in aging)9 and local (e.g., reduction of hippocampal volume in Alzheimer’s disease)10. The T2 data (Fig 1b,d) is a FLAIR (fluid-attenuated inversion recovery) acquisition that also
