Researchers at the German Primate Center (DPZ) in Göttingen have identified the cellular mechanisms behind the common marmoset's small, smooth brain, publishing their findings in Science Advances in late September 2026. The study reveals that subtle changes in neural progenitor cells during embryonic development slow neuron production, distinguishing the marmoset brain from the larger, folded brains of most other primates, including humans. This discovery offers new details on how primate brains evolved their varied shapes and sizes, particularly the extensive folds found in the human brain. The insights could also advance research into human developmental brain disorders, where similar cellular processes might be affected. Marmosets are increasingly used as model organisms in neurodevelopmental research due to certain similarities in their brain development to humans.

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A study led by the Junior Research Group "Brain Development and Evolution" at the DPZ aimed to determine the cellular changes responsible for the marmoset brain's distinct morphology. The team discovered that the marmoset brain initially develops similarly to a larger, folded primate brain, but specific processes later in development reduce the production of nerve cells, thereby limiting brain growth and folding. To investigate this, scientists utilized brain organoids, which are three-dimensional tissue structures derived from pluripotent stem cells that mimic developing brain characteristics. Experiments with these organoids, supported by studies on fetal marmoset tissue, showed significant differences in neural progenitor cells, the precursors to neurons. Marmoset neural progenitor cells were observed to divide more slowly and exhibit simpler branching structures than those in other primates. They also had a shorter developmental period for rapid proliferation. These combined factors lead to a substantial reduction in the overall generation of neurons, a mechanism the researchers termed a "cellular braking mechanism" that explains the marmoset brain's smaller size and lack of folding. Professor Dr. Michael Heide, group leader of Brain Development and Evolution at DPZ, was listed as an author on the Science Advances paper. Lidiia Tynianskaia, a PhD student, was a lead author.

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