Evaluating the angular power spectrum of cortical folding

The most defining feature of the cortex is its folding structure. While these peaks and valleys can be coarsely characterised using measures of cortical structure such as gyrification and fractal dimensionality, these are not directly sensitive to the different scales of folding that comprise the brain’s cortical structure. Here we developed an approach for characterising the angular power spectrum of cortical folding using spherical harmonics and informed by prior research investigating the cosmic microwave background. In this work, we ultimately yielded a single summary measure that is sensitive to minor folds along the cortical gyri and sulci and is sensitive to agerelated differences in cortical structure.