Otto Hahn Medal for Meike Hettwer and Joëlle Schroën
At the annual meeting of the Max Planck Society on June 18, 2026, the Otto Hahn Medal was awarded for outstanding scientific achievements related to a doctoral dissertation. This year, Meike Hettwer from the Cognitive Neurogenetics Research Group and Joëlle Schroën from the Neuropsychology Department at the Max Planck Institute for Cognitive and Brain Sciences (MPI CBS) received two of these coveted awards. In this short interview, they answer three questions about their research.
Your dissertation has just been awarded the Otto Hahn Medal. What makes your work so special?
Meike Hettwer:
My doctoral dissertation examines a central question in psychiatric research: Why are similar brain networks affected in so many psychiatric disorders, and when and where are they particularly vulnerable to pathological changes? To answer this question, I combined two perspectives. First, I used large international datasets to create a kind of “map” of brain changes associated with mental disorders. In doing so, I was able to show that these changes do not occur randomly but are influenced by fundamental properties of brain organization, such as network and cytoarchitecture. Second, I investigated how vulnerability to mental disorders develops as early as adolescence. To this end, I analyzed imaging data from adolescents who were exposed to stressful environmental factors such as trauma or difficult family circumstances. It was particularly interesting that adolescents who remained mentally healthy despite such stressors exhibited different developmental trajectories in the microstructure of the cortex compared to adolescents who developed mental health symptoms under similar stress. In short, the combination of these two approaches provides insights into the spatial and temporal organization of increased vulnerability to psychopathological brain changes.
This not only helps us better understand the biological foundations of mental illness, but could also, in the long term, help us identify at-risk groups earlier and provide targeted support at the right time.
Joëlle Schroën:
My doctoral dissertation addresses a question that concerns all of us: How does our brain understand language? Until now, many researchers have relied on lesion studies. These studies examine people with brain injuries. They are very useful for identifying which brain regions are important for language comprehension. However, they cannot reveal exactly when these regions become active during comprehension or what role they play at that moment.
I wanted to close this gap. To do so, I combined two neuroscientific methods: TMS and EEG. This approach allows me not only to understand where something happens in the brain, but also when it happens, and even to test whether a particular brain region is causally involved in comprehension. In this way, we gain a much more complete picture of how our brain processes meaning.
What motivates you to work on this particular topic?
Meike Hettwer:
When looking at neurobiological research on psychiatric disorders, one quickly encounters some difficulties, as the boundaries between different diagnoses (e.g., anxiety disorders and depression) are often blurred. Many patients receive several different diagnoses over the years, and many symptoms (e.g., sleep problems) are associated with multiple diagnoses simultaneously—that is, they are nonspecific. I am particularly interested in the extent to which these phenomena are linked to similarities in brain changes, with certain brain regions or networks proving to be “generally vulnerable.” In the long term, this could be a starting point for integrative therapeutic strategies. However, I am also particularly motivated by the goal of determining when and where this vulnerability is most pronounced and could benefit most from interventions. One idea is that the various brain networks are malleable to different degrees during different stages of development. During these so-called “plastic phases,” children and adolescents may not only be particularly vulnerable to negative environmental influences but also particularly responsive to interventions and positive support from their family and friends.
Joëlle Schroën:
I find language especially fascinating because it is something we use every day and usually take for granted. I am intrigued by the fact that our brain can derive meaning from nothing more than sound waves. When we listen to someone speaking, what reaches our ears are merely vibrations in the air. Yet within fractions of a second, we understand words, sentences, and ideas. I find it remarkable that this process feels so effortless, even though an enormous amount is happening in the brain.
You have completed your award-winning dissertation. What comes next?
Meike Hettwer:
As a postdoc at the University of Pennsylvania in the U.S., I am investigating the microstructural development of the brain in adolescents to determine when specific brain structures are in phases of plasticity and could benefit most from interventions. At the same time, I am continuing work that I began at the MPI-CBS. Over the past few years, we have compiled the largest imaging dataset of psychiatric patients, with approximately 170 institutions from 6 continents sharing their data with us. Using this vast resource, I am currently investigating patterns of structural changes in the brain associated with psychiatric disorders, as well as variability and heterogeneity among patients with the same diagnosis. The goal remains to understand why and when specific brain regions exhibit particular vulnerabilities and could benefit most from integrative prevention and treatment approaches.
Joëlle Schroën:
After earning my doctorate, I returned to my home country and am currently working as a postdoctoral researcher at Tilburg University. My dissertation helped me better understand how the adult brain processes language. This naturally led me to the next question: How do children acquire language? Young children accomplish something extraordinary. In just a few years, they learn thousands of words and develop a complex understanding of meaning, often at an impressive pace. I am interested in how they manage this and why some children acquire language more quickly than others.
