Most primate species have relatively large brains marked by pronounced bulges and furrows. Common marmosets are a striking exception: their brains are smooth and virtually unfolded. This contrast has long raised questions about how brain shape is determined during development.
A recent study described on Phys.org used brain organoids—miniature, lab-grown models of brain tissue—to investigate this difference. By examining how organoids develop, researchers are uncovering the cellular and mechanical processes that lead to folded or smooth brain surfaces in different primates.
The findings help explain why brain shape varies so widely across species and how such differences arise during embryonic growth. Understanding these mechanisms may also offer broader insight into brain evolution and the origins of structural brain variations.