Other attributes
A brain atlas must begin by defining a coordinate system to refer to specific points within the brain. In most coordinate systems (such as Talairach and MNI coordinates), x is the left-right axis, y is the posterior-anterior axis, and z is the inferior-superior axis. These coordinates can then be used to define the boundaries of anatomical structures based on brain imaging data. Because atlases are built from observation of actual brains and brains vary in the details of their anatomy, the exact size and shape of the brain and its components within this space depend on the atlas. Furthermore, some atlases are concerned with features of the brain that are defined functionally (such as the Human Brainnetome Atlas) or genomically (such as the Allen Brain Atlas) rather than anatomically.
