Isabell Ehmer

Isabell Ehmer

PhD student

Phone: +31 20 5665495


“Der Mensch kann tun was er will; er kann aber nicht wollen was er will.”

(“Man can do what he wants but he cannot want what he wants.”)

― Arthur Schopenhauer, Essays and Aphorisms

Except for the pragmatic notion of social and environmental constraints on behavior, one might expend the famous free-will quote of Schopenhauer by stating that: “wanting cannot change will, but repeated action can”. Repetition of actions can have positive or negative effects on behavior in general. Negative examples clearly involve compulsive behavior and addiction, while newly acquired fitness routines or social interactions highlight positive effects. With our research endeavor, we are exploring how to enhance people’s behavioral control over their wanting after their intentions and actions are in disagreement.


Compulsivity is a debilitating condition characterized by a strong urge to perform certain actions or action sequences at the expense of free choice and behavioral flexibility, frequently leading to negative consequences. Compulsive behavior is not only a core symptom of Obsessive-compulsive disorder (OCD) but is also present in many different psychiatric and neurological disorders. Patients suffering from compulsive behavior are usually aware of the inappropriateness of their actions without being able to quit and change for the better.

In my work as a translational researcher, I aim at unravelling brain mechanisms that contribute to development or maintenance of compulsive behavior in order to improve treatment options for patients.  In my ongoing research, I focus on decision-making, behavioral control and reward processing in normal and compulsive behavior. For this purpose, Sapap3 knockout mice, a genetic animal model of compulsivity, are trained in behavioral tasks investigating how employment of goal-directed and habitual action strategies, or utilization of environmental feedback cues, are related to compulsive behavior. A current hypothesis addresses the question of whether alteration of the brains reward circuit causes inappropriate enhancement of certain ritualistic behaviors, thereby limiting natural choice and flexibility. To study this research question, elaborated rodent behavioral testing and analysis is combined with neuroimaging/modulation techniques such as in vivo fast-scan cyclic voltammetry and deep brain stimulation.


With a strong background in neuroscience (MSc Brain and Cognitive science, UvA, NL), psychology (BA Psychology, Leiden University, NL) and social sciences (University of Applied Sciences Fulda, DE), my goal is to link fundamental and clinical neuroscience by not only enhancing understanding of the complex nature of (compulsive) behavior, but also by suggesting means to promote healthy behavior that is challenged by stress or disease. I strive to put this ambition into action in my current position as a PhD candidate in the Denys/ Willuhn group and as a medical writer at the Netherlands Brain Bank.