About the team

The Systems Neurology research group is led by associate professor and neurologist Rick Helmich. The group consists of a large variety of people, ranging from postdocs, PhD-candidates, MSc-students, and BSc-students. With backgrounds ranging from medicine, psychology, cognitive neuroscience, and molecular life sciences, we all aim to unravel the neural mechanisms that give rise to neurological symptoms.

Rick Helmich

It is my passion to understand the cerebral mechanisms that lead to neurological diseases, and use these insights to develop new therapies for patients with movement disorders. I work as a neurologist and associate professor specializing in Parkinson’s disease and tremor disorders, both at the Radboud University Medical Centre and at the Donders Institute. I am very much inspired by clinical observations in patients, and use neuroimaging and neurophysiology to understand the underlying mechanisms. I am particularly intrigued by the profound effects of psychological stress on many neurological movement disorders, by the way patients can compensate for brain dysfunction, and by the different ways in which tremor can manifest itself.

Filip Grill

I am originally from the south of Sweden but moved to the north to pursue a PhD in cognitive neuroscience at Umeå center for Functional Brain Imaging under the supervision of Anna Rieckmann and Lars Nyberg. In my PhD I investigated how dopamine release in the human striatum is related to reinforcement learning using hybrid PET/MR brain imaging and computational modelling of behavior.

In July 2022, I joined the Donders Institute as a joint postdoc in the labs of Rick Helmich and Roshan Cools to study how Parkinson’s patients estimate how controllable their environment is. The project is part of a larger consortium involving a team of international researchers dedicated to investigate the pathological progression of Parkinson’s disease.


Michiel Dirkx

Michiel Dirkx is a post-doctoral researcher at the Donders Centre for Cognitive Neuroimaging and a neurologist in training at the Radboud University Medical Centre.

I obtained my medical degree at the Radboud University Nijmegen in 2018, and my PhD thesis (“Neural mechanism of Parkinson’s tremor”) in 2020. Since 2020, I work as a post-doctoral researcher where I focus on the pathophysiology of movement disorders, especially tremor and Parkinson’s disease. For this, I use methods such functional MRI and electrophysiology (EMG/accelerometry), which I use for cerebral network analyses such as Dynamic Causal Modelling and a graph-theoretical methods.

Martin Johansson

Martin joined the Systems Neurology lab for his PhD project in 2018 and transitioned to a post-doctoral research position in 2023.

My research focuses on brain mechanisms that underlie symptom progression in Parkinson’s disease, which I investigate through the longitudinal analysis of (f)MRI and clinical data. I am particularly interested in understanding how pathological and compensatory alterations in the brain can shape the motor phenotype and progression of individual patients. Currently, I am testing the hypothesis that motor progression depends on the decline of cortical mechanisms that are recruited to compensate for pathological dysfunction in the basal ganglia.



Anouk van der Heide

During my studies in Biomedical Sciences, I quickly became fascinated by the human brain. My goal has always been to help people with neurological disorders. I have been working at the Donders Institute since 2018, where I study the impact of psychological stress on Parkinson’s Disease. I want to understand why some Parkinson’s patients develop mental disorders while others don’t. I hope that we can reduce the severity of Parkinson’s symptoms by acting on the stress system, either pharmacologically or with behavioral strategies like mindfulness. Personally, I experience mindfulness in playing several musical instruments and singing.

Jorryt Tichelaar

I received my master degree in molecular life science at the Radboud University in Nijmegen. In my masters, I worked with Bernhard Englitz and applied electrophysiology and optogenetics to investigate neural activity during auditory sensory substitution. I thoroughly enjoyed the computational analysis and performed a second internship in the group of Tobias Elze at Harvard Medical School. Here I applied machine learning to model the temporal evolution of functional vision loss in glaucoma patients.

In my PhD, I investigate impulse control disorders (ICD) in Parkinson’s disease. For example, I assess how the reward circuitry is different in patients with ICD and whether we can contribute these differences to inflammation. Eventually, I hope to predict which patients are susceptible to develop ICD.


Marlous Verhulst

My name is Marlous Verhulst and I studied Technical Medicine at the University of Twente. During my graduation project I developed great interest in brain damage in patients after cardiac arrest and the long-term consequences of this damage. Therefore, I started my PhD at the University of Twente and Rijnstate Hospital in Arnhem in 2020. In collaboration with the Donders Institute, I research the predictive value of early MRI markers for long-term cognitive impairments in cardiac arrest survivors. In my free time I like to play tennis or go for a ride on my gravel bike on the Veluwe.

Kevin van den Berg

Kevin van den Berg obtained his medical degree at the Radboud university medical centre and subsequently started with a PhD-trajectory investigating Parkinson’s tremor.

Even before starting medical school in 2015, I was fascinated by neurology and neuroimaging. During the summer of 2018, I went to the National Institutes of Health (NIH) in the USA for a research internship. There, I investigated the role of the cerebellum in Parkinson’s tremor. Having obtained my medical degree in February 2022 at the Radboud university medical centre, I wanted to delve deeper into the underlying mechanisms of Parkinson’s tremor. As of March 2022, I started a PhD-trajectory investigating the role of the cerebellum in Parkinson’s tremor and the cerebral mechanisms behind Parkinson’s tremor progression. My ultimate goal is to become a neurologist specialized in movement disorders. In my free time, I try to obtain a good dose of exercise and (especially) music to maintain a healthy body and mind.


Franziska Goltz

I am Franziska and I joined Rick Helmich’s lab in 2023. Originally from a small village in Germany, I moved to Nijmegen in 2014, where I obtained my bachelor’s degree in Psychology and my master’s degree in Cognitive Neuroscience. In my research, I am interested in network neuroscience and understanding the healthy and pathological brain from that perspective, but I am also very passionate about music, music therapy and other non-pharmacologic treatment methods. With my research, I aim to improve our understanding of Parkinson’s disease (PD), how to treat PD effectively and how to support the life of people with PD the best way possible. In my PhD, I am very happy to bring my interests together and investigate the clinical effects of mindfulness based cognitive therapy and the cerebral mechanisms underlying stress (reduction) in people with PD.

Nienke Timmermans

After I obtained my master degree in Technical Medicine in 2023, I started as a PhD-candidate at the at the Radboud University Medical Center in collaboration with the Donders institute. During my PhD, I will focus on quantifying Parkinson’s tremor in relation to stress. For this, I will mainly use the large amount of sensor data (accelerometry and photoplethysmography) that was collected with a smartwatch during daily-living as part of the Personalized Parkinson Project. By analysing these signals, I hope that we can obtain new insights into the occurrence of tremor in daily life and the influence of stress, ultimately leading to improved treatment for Parkinson’s tremor. In my free time I enjoy running, cycling and reading, which helps me to reduce my own stress levels.

Iris Visser

I am Iris and I finished my master’s degree in Technical Medicine at the University of Twente in 2023. During my graduation internship, I focused on ultrasound measurements of the optic nerve in comatose patients after cardiac arrest on the intensive care. This sparked my interest in research and neurology specifically. In June 2023, I started my PhD at the Canisius-Wilhelmina Hospital in Nijmegen in collaboration with Radboud University Medical Center and the Donders Institute. I will investigate whether treatment success of botulin toxin injections in patients with dystonic tremor syndrome can be predicted by clinical and electrophysiological tremor characteristics. Furthermore, I will explore whether muscle ultrasound might be able to guide these injections.