Material stiffness, geometric effect, instability – these are the kind of words Silvia Budday uses when talking about her research. This is hardly surprising, as she is a mechanical engineer. What does come as something of a surprise is what she is using these terms to describe: namely the brain. “Mechanics”, says Silvia Budday, “plays an important role in brain function.” This is a reference to the mechanical forces that give the three to four millimetre-thick cerebral cortex its characteristic shape: during the embryonic development stage, the outer layer of the cerebrum with its billions of nerve cells becomes wrinkled, which is what causes its familiar ridges.
Optimal growth of the brain
From a mechanical viewpoint, the growth of the brain is merely a matter of instability: as the cells develop, the outer layer grows more quickly than the inner layer, where the nerve connections are to be found. This produces compressional stress, which leads to deformation – a bit like when the skin of a grape becomes wrinkled when the liquid is removed from it and it becomes a raisin. In the brain, it is these deformations that allow the higher cognitive functions to develop in the first place: the folds make it possible for the number of nerve cells to increase while minimising the transmission distance between the cells at the same time.
Test methods for examining brain tissue
Normally, engineers study the mechanics of materials such as concrete, steel or plastic. In her research group BRAINIACS (BRAIn mechaNIcs ACross Scales: Linking microstructure, mechanics and pathology) at Friederich-Alexander-Universität Erlangen-Nürnberg, Silvia Budday develops test methods that are designed to examine tissue from the brains of pigs, cows or even deceased human patients. “The risk that this will damage or destroy the extremely soft tissue is considerable”, reports Budday. “We first needed to optimise our test equipment.”
3D brain models for diagnosis and surgery
Budday and her team use the data they obtain from the measurements as the basis for developing mathematical models and simulations. They are designed to predict how the brain will change shape under pressure. In the future, such models may then allow surgical techniques to be refined – like when a tumour needs to be removed – or neurological diseases to be detected at an earlier stage. This is because certain forms of schizophrenia, and indeed autism and epilepsy, are associated with characteristic deformations of the cortex.
Close collaboration with doctors and anatomists
The models are not intended to describe only the externally visible structure of the brain, however. That is why Silvia Budday’s working group is collaborating closely with doctors and anatomists at the university. “The processes of pathological folding are already well described on the cellular level. Our goal is to understand how this microstructure is related to the macrostructure”, says Budday.
They still have a long way to go before this happens, however. Silvia Budday has been working on biomechanics ever since her master’s degree course, and for the PhD she completed in 2017 she cooperated with a research group at Stanford University, which is likewise researching the mechanics of the brain. Budday has been heading her own group since October 2019 – financed by the Emmy Noether Programme of the German Research Foundation (DFG) for young researchers.
Establishing her own field of research
“It’s a great programme”, enthuses Budday. “It gives you the chance at a very early stage to establish your own field of research.” She uses the one million euros that the programme is making available to her over the coming three years to fund her team: two doctoral students and one postdoc. In addition, the laboratory at the Institute for Engineering Mechanics (LTM) had to be adapted for work with tissue samples. Brain tissue, as Budday puts it, is softer than jelly. Ultimately, however, the methods she is developing with her team should be transferrable to other types of tissue, too.
Opportunities in the field of brain research
German Center for Neurodegenerative Diseases (DZNE)
The DZNE researches what causes diseases of the brain and nervous system and develops methods of prevention, therapy and patient care. The central focus is on neurodegeneration, a pathological and slow process that damages nerve cells and occurs in diseases such as Alzheimer’s, Parkinson’s and amyotrophic lateral sclerosis (ALS). Working at ten research institutions, the scientists attempt to understand the underlying molecular processes and conduct clinical studies. For the purposes of developing new therapies and drugs, the DZNE cooperates with other scientific institutions and companies – in Germany and around the world.More