McKelvey School of Engineering

Model Brains-on-a-Chip Reveal the Physics of Brain Folding


…Basically, by confining the growth to two dimensions, researchers were able to watch a developing set of stem cells turn into brain cells and fold.

Why are the organoids folding? It appears that as the neurons develop, their cellular nuclei migrate to the outer end. As this occurs, the whole structure appears to buckle and fold inwards. The phenomenon on the chip looks really similar to the folding effect of regular brains. Brains themselves need to fold, we think, for increased surface area—more brain processing power in a smaller space.

But, again, organoids are not brains—not even tiny brains. In real brains, entire cells are arranging themselves to form much larger structures. “Significant differences in scale and structure, however, may limit the ways in which organoids can be used to study the mechanics of cortical folding,” Larry Taber, researcher in Biomedical Engineering at Washington University in St. Louis wrote in a Nature Physics News and Views. But these models are still important. They may shed light on fetal brain-shape development, or one day help explain why animals in the same species have similar brain folds, he writes.