New research completed by Harvard’s John A. Paulson School of Engineering and Applied Sciences has unlocked a brain fold replication model that may help scientists better understand the inner workings of the brain. Through 3D replication of the folds in the human brain, the research team showed that though there are multiple molecular processes that ultimately determine the cellular events, the actual cause of brain folds is essentially a mechanical instability that has been linked to buckling.

The Making of a Gel Brain

Researchers made a gel model, a three-dimensional replication of a smooth fetal brain by way of MRI imaging. The surface of the model was coated with a layer of elastomer gel, which acted as an analog of the cortex. In order to mimic the cortical expansion, the model brain was immersed into a solvent that absorbed into the outermost layer, leading to swelling relative to the deeper regions of the gel brain. Within a matter of minutes of immersion in the liquid solvent, compression resulted in the formation of folds in the model, similar in shape and size to that of actual brain folds.

Even the researchers were impressed with the similarities in the gel brain and the actual human brain. Jun Chung, post-doctoral fellow and co-first author of the paper said, “When I put the model into the solvent I knew there should be folding, but I never expected that kind of close pattern compared to the human brain.” He went on further to say, “It looks like a real human brain.”

The relevance and key to those similarities lies in the unique shape of the human brain. Chung states, “The geometry of the brain is really important because it serves to orient the folds in certain directions.” Chung’s claims are that their model, which on a large geometric scale is the same as a real human brain, had the same curvature, which led to the formation of folds that so closely matched that of a real fetal brain.

What’s In a Brain Fold?

There are many ways that one can rationalize the folds of the human brain from an evolutionary perspective. For instance, it was once believed that folded brains were a result of evolution of the large cortex to fit into the small volume with the benefit of decreasing the length of neuronal wiring and therefore improving cognitive function.

What was previously unexplained was how the brain folds. Over many years of study there have been many hypotheses proposed. However, none of these developments have been used directly to lead to testable predictions. Now, the Harvard John A. Paulson School of Engineering and Applied Scientists researchers, in collaboration with scientists in France and Finland, have been able to show that the ultimate cause of brain folds is the result of a simple mechanical instability that is most likely a result of buckling.

Why It Matters

The brain will not be exactly the same in all humans, but all brains should feature the same major folds, which indicate good health. This research shows that if the global geometry of the brain is interrupted, or part does not mature/grow properly, then the major folds might not be present where they should; which may lead to dysfunction of the brain. This study helps scientist to better understand the folds in the brain in more depth, which may help unlock the innermost workings of the human brain and could ultimately explain some brain disorders.

Sources

Harvard John A. Paulson School of Engineering and Applied Sciences. (2016, February 1). New research replicates a folding human brain in 3D: Study substantiates a simple mechanical framework for how the human brain folds. ScienceDaily. Retrieved February 2, 2016 from www.sciencedaily.com/releases/2016/02/160201122842.htm

‍