Systematic cortical thickness and curvature patterns in primates.

Area of Science:

• Comparative neuroanatomy
• Neuroscience
• Primate brain evolution

Background:

• Humans exhibit consistent cortical thickness variations, with thicker gyri and thinner sulci, potentially due to mechanical forces during folding.
• Similar patterns are expected in other primate species, but how cortical thickness scales with brain size, form, and folding remains unknown.

Purpose of the Study:

• To investigate the scaling of cortical thickness relative to surface geometry across 12 diverse primate species.
• To explore common trends in primate brain anatomy that transcend species-specific differences.

Main Methods:

• Reconstructed 3D brain surfaces from publicly available neuroimaging data for 12 primate species.
• Utilized a surface-based computational pipeline to analyze cortical thickness, folding, brain size, and geometric features (curvature, shape, sulcal depth).

Main Results:

• Consistent cortical thickness variations along a gyral-sulcal spectrum were found in all 12 species, with convex shapes being thicker than concave shapes.
• The difference in thickness between gyri and sulci increased with increasing brain size across species.
• Results suggest a systematic folding mechanism linking local cortical thickness to brain geometry.

Conclusions:

• Cortical thickness patterns are conserved across primate species, varying along a gyral-sulcal spectrum.
• Brain size is a key factor influencing the magnitude of thickness differences between gyri and sulci.
• The findings support a mechanical basis for cortical folding and thickness distribution, applicable across primate evolution.