Structure of a Brain Atlas

Brain atlases provide a structural framework to address these difficulties. Most brain atlases (regardless of species) are based on a detailed representation of a single subject's anatomy (or at best a few) in a standardized 3D coordinate system, or stereotaxic space. The earliest attempts were created from post mortem specimens (e.g., [9,62,71,77,89,90,102-104]). Such atlases take the form of anatomical references or represent a particular feature of the brain [124,125]. They also may focus on the cellular architecture of the cerebral cortex [9], or even a specific neurochemical distribution [61].

2.1 Brain Templates

The single subject chosen to represent a population acts as a template on which other brain maps (such as functional images) can be overlaid. The anatomic data provides the additional detail necessary to accurately locate activation sites, as well as providing other structural perspectives such as chemoarchitecture. A common 3D coordinate space is a prerequisite, as it supplies a quantitative spatial reference system in which brain data from multiple subjects and modalities can be compared and correlated.

Since there is neither a single representative brain nor a simple method to construct an average anatomy or to represent the complex variations around it, the construction of brain atlases to represent large human populations has become a major research focus [63]. Population-based atlases can be used to guide knowledge-based image analysis algorithms and can even support pathology detection in individual subjects or groups. Single modality atlases may also be insufficient,

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