The degree of cortical folding (GI) and the relation between sulci and borders of cyto- and receptorarchitectonically defined areas were analyzed in postmortem human brains. The GI reaches adult levels (with highest values in the association cortices) around birth and does not decrease during aging. It shows a sex-dependent left-over-right asymmetry. Sulci and borders of architectonical areas coincide only in a few examples; thus, sulci are not generally valid landmarks of the microstructural organization of the cortex. Individual sulci were studied in 3D-reconstructed MRI sequences of living brains. A considerable intersubject variability of the distances between the sulcal surfaces of individual brains and their mean sulcal surfaces is apparent. The depth of the central sulcus varies with manual skill and handedness.

The degree of cortical folding (GI) and the relation between sulci and borders of cyto-and receptorarchitectonically defined areas were analyzed in postmortem human brains. The GI reaches adult levels (with highest values in the association cortices) around birth and does not decrease during aging. It shows a sex-dependent left-over-right asymmetry. Sulci and borders of architectonical areas coincide only in a few examples; thus, sulci are not generally valid landmarks of the microstructural organization of the cortex.Individual sulci were studied in 3D-reconstructed MRI sequences of living brains. A considerable intersubject variability of the distances between the sulcal surfaces of individual brains and their mean sulcal surfaces is apparent. The depth of the central sulcus varies with manual skill and handedness. Hum.