  The universal scaling law of cortical morphology describes cortical folding
as the covariance of average grey matter thickness, pial surface area, and
exposed surface area. It applies for mammalian species, humans, and across
lobes, however it remains to be shown that local cortical folding obeys the
same rules. Here, we develop a method to obtain morphological measures for
small regions across the cortex and correct surface areas by curvature to
account for differences in patch size, resulting in a map of local morphology.
It enables a near-pointwise analysis of morphological variables and their
regional changes due to processes such as healthy ageing. We confirm
empirically that the theorised covariance of morphological measures still holds
at this level of local partition sizes as predicted, justifying the use of
independent variables derived from the scaling law to identify regional
differences in folding, subject-specific abnormalities, and local effects of
ageing.
