The role of physical forces in cortical morphogenesis*

Between individuals and across species, brain morphology is strikingly consistent in some significant ways. One example is a characteristic pattern of cortical thickness in gyrencephalic, or folded, brains - thick outer folds, or gyri, and thin inner folds, or sulci. This raises the question: which factors (genetic, biochemical, physical, and/or others) lead to this morphological consistency? In a recent combined theoretical, numerical, and experimental study, we found that the physical forces generated by buckling instabilities were sufficient to generate physiological gyral-sulcal thickness ratios. We now consider the more complex, fully three-dimensional pattern of cortical thickness in the brain, and investigate the role of physical forces in its evolution, consistency, and variability.