DEFORMABLE ATLASES

Striking variations in brain structure, especially in the gyral patterns of the human cortex, present fundamental challenges in human brain mapping.

• Alzheimer's Disease (AD) atlas
  The AD atlas was constructed using specialized strategies developed for population-based averaging of anatomy. Sets of high-dimensional elastic mappings, based on the principles of continuum mechanics, reconfigured the anatomy of a large number of subjects in an anatomic image database. These mappings generated a local encoding of anatomic variability, and were used to create a crisp anatomical image template with highly-resolved structures in their mean spatial location. Specialized approaches were also developed to average cortical topography. Since cortical patterns are altered in a variety of diseases, gyral pattern matching was used to encode the magnitude and principal directions of local cortical variation. In the resulting cortical templates, subtle features emerged. Regional asymmetries appeared that were not apparent in individual anatomies. Population-based maps of cortical variation reveal a mosaic of variability patterns that segregate sharply according to functional specialization and cytoarchitectonic boundaries.