Engineers study brain folding in higher mammals

October 01, 2007

Engineers at Washington University in St. Louis are finding common ground between the shaping of the brain and the heart during embryonic development.

Larry A.Taber, Ph.D., the Dennis and Barbara Kessler Professor of Biomedical Engineering, and Phillip Bayly, Ph.D., Hughes Professor of Mechanical Engineering, are examining mechanical and developmental processes that occur in the folding of the brain's surface, or cortex, which gives the higher mammalian brain more surface area (and hence more intellectual capacity) than a brain of comparable volume with a smooth surface.

Folding is very important in human brain development because some of the worst neurological problems such as schizophrenia, autism and lissenchephaly (smoothness of the cortex, found with severe retardation) are associated with abnormal brain folding. The neuromuscular disorder dystonia is possibly associated with faulty connectivity in the brain, which has been hypothesized to affect cortical folding. The researchers hope that increased understanding of brain folding might someday help prevent such diseases.

Although folding is generally what makes higher mammals smart, Albert Einstein had an abnormally folded brain that resulted in genius. Certain folds in his brain were absent, which might have enabled the area associated with mathematical reasoning to be larger than normal because it didn't have a boundary to restrict its growth.

Looping, folding

According to Taber, the heart and the brain both begin as simple tubes that eventually develop in totally different ways. Looping is a key phenomenon in the early embryo where the tubular heart bends and rotates in a precise manner. Taber has found that the processes of bending and rotation in the embryonic heart are actually driven by at least two different mechanical forces. His research could help scientists better understand the roles physics and mechanics play in the normal developing heart and in the genesis of heart defects.

Bayly researches the mechanics of brain injury, recently looking into brain deformation due to acceleration of the intact skull. Both have long been aware of a theory posited by their colleague, David Van Essen, Ph.D., the Edison Professor of Neurobiology and head of the School of Medicine's Department of Anatomy and Neurobiology. Van Essen's hypothesis, published in 1997 in the journal Nature, is a mechanical theory based on tension in the axons¬ (the wiring through which nerve cells communicate). The essence of the hypothesis is that tension in axons is the driving force of folding. Van Essen's theory is one of only about a half dozen in the literature concerning the mechanical process of folding. In contrast, much more is known about the genetics of the brain and heart.

"We're not sure of the similarities between heart looping and brain folding," Taber said. "But there are only a handful of processes that cells use to create shape and form in the embryo. Developing brain and heart cells have the same basic tool set but somehow they integrate them in different ways. We're concerned primarily with the mechanics of how these organs are constructed."

Results so far are only preliminary. Post-doctoral researcher Gang Xu has obtained unexpected data from adult mouse brains in studies performed primarily to demonstrate feasibility of their approach.

"We've observed measurable, sustained tension in the axons," Bayly said. "This is significant, because it's what David Van Essen's theory predicts is necessary for folding."

They are now doing MRI research on newborn ferrets. The ferret is the smallest mammal that has a folded brain, and unlike humans, folding occurs after the animal is born.

Washington University post doctoral in biomedical engineering researcher Gang Xu gave a presentation on the research at the Biomedical Engineering Society Annual Meeting, held Sept. 27-29 in Los Angeles.
-end-
The research is funded by the National Science Foundation for four years at $987,000.

Washington University in St. Louis

Related Brain Articles from Brightsurf:

Glioblastoma nanomedicine crosses into brain in mice, eradicates recurring brain cancer
A new synthetic protein nanoparticle capable of slipping past the nearly impermeable blood-brain barrier in mice could deliver cancer-killing drugs directly to malignant brain tumors, new research from the University of Michigan shows.

Children with asymptomatic brain bleeds as newborns show normal brain development at age 2
A study by UNC researchers finds that neurodevelopmental scores and gray matter volumes at age two years did not differ between children who had MRI-confirmed asymptomatic subdural hemorrhages when they were neonates, compared to children with no history of subdural hemorrhage.

New model of human brain 'conversations' could inform research on brain disease, cognition
A team of Indiana University neuroscientists has built a new model of human brain networks that sheds light on how the brain functions.

Human brain size gene triggers bigger brain in monkeys
Dresden and Japanese researchers show that a human-specific gene causes a larger neocortex in the common marmoset, a non-human primate.

Unique insight into development of the human brain: Model of the early embryonic brain
Stem cell researchers from the University of Copenhagen have designed a model of an early embryonic brain.

An optical brain-to-brain interface supports information exchange for locomotion control
Chinese researchers established an optical BtBI that supports rapid information transmission for precise locomotion control, thus providing a proof-of-principle demonstration of fast BtBI for real-time behavioral control.

Transplanting human nerve cells into a mouse brain reveals how they wire into brain circuits
A team of researchers led by Pierre Vanderhaeghen and Vincent Bonin (VIB-KU Leuven, Université libre de Bruxelles and NERF) showed how human nerve cells can develop at their own pace, and form highly precise connections with the surrounding mouse brain cells.

Brain scans reveal how the human brain compensates when one hemisphere is removed
Researchers studying six adults who had one of their brain hemispheres removed during childhood to reduce epileptic seizures found that the remaining half of the brain formed unusually strong connections between different functional brain networks, which potentially help the body to function as if the brain were intact.

Alcohol byproduct contributes to brain chemistry changes in specific brain regions
Study of mouse models provides clear implications for new targets to treat alcohol use disorder and fetal alcohol syndrome.

Scientists predict the areas of the brain to stimulate transitions between different brain states
Using a computer model of the brain, Gustavo Deco, director of the Center for Brain and Cognition, and Josephine Cruzat, a member of his team, together with a group of international collaborators, have developed an innovative method published in Proceedings of the National Academy of Sciences on Sept.

Read More: Brain News and Brain Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.