Felix Klaassen

Felix Klaassen

Felix obtained his background in Psychology (BSc) and Cognitive Neuroscience (MSc) at the Radboud University in Nijmegen. After completing his Master’s, Felix joined Prof. Alan Sanfey’s Decision Neuroscience lab as a Research Assistant (RA) and lab manager where he developed an interest in decision-making. Here he also became familiar with incorporating a variety of research methods, such as threat of electrical shock, physiology, and computational modeling. He next joined the EPAN lab as RA to set up the new Dare2Approach ERC-CoG project. Since 2019 he worked on this project as a PhD student.

During his PhD, Felix investigated the role of defensive freezing states in approach-avoidance decision-making under threat. For this, he combined behavioral, physiological, and neural measurements with (computational) modeling of approach-avoidance decisions in the face of varying reward and threat prospects. In his first study, he investigated the interaction between freezing states (assessed through heart rate and body sway) and subjective value computations and passive/active avoidance tendencies. Next, he probed the neural circuits that may support these value-based decision-making processes during freezing using functional magnetic resonance imaging (fMRI). Finally, using magnetoencephalography (MEG), he investigated how these brain circuits represent reward and threat information during freezing while the decision is being made. Together, these studies outline the role of defensive psychophysiological states in decision-making under threat (see refs below).

During his postdoc, Felix tests how deep brain stimulation of the periaqueductal gray affects defensive physiological responses and go/nogo decisions (in the context of freeze/fight).



Klaassen F.H., de Voogd L.D., Hulsman A.M., O’Reilly J.X., Klumpers F., Figner B., & Roelofs K.  (2023). The neurocomputational link between defensive cardiac states and approach-avoidance arbitration under threat. BioRxiv preprint. https://doi.org/10.1101/2023.11.10.566569

Roelofs K, Klaassen F.H., & Dayan P. (2023). Reply to ‘Post-encounter freezing during approach–avoidance conflict: the role of the hippocampus’. Nature Reviews Neuroscience, 24, 453–454. https://doi.org/10.1038/s41583-023-00704-x

Klaassen F.H., Held L., Figner B., O’Reilly J.X., Klumpers F., de Voogd LD., & Roelofs K. (2021). Defensive freezing and its relation to approach-avoidance decision-making under threat. Scientific Reports, 11, 12030. https://doi.org/10.1038/s41598-021-90968-z

Livermore J.J.A., Klaassen F.H., Bramson B., Hulsman A.M., Meijer S.W., Held L., Klumpers F., de Voogd L.D., & Roelofs K. (2021). Approach-Avoidance Decisions Under Threat: The Role of Autonomic Psychophysiological States. Frontiers in Neuroscience, 15:621517. https://doi.org/10.3389/fnins.2021.621517

Van Baar, J.M., Klaassen F.H., Ricci, F., Chang, L.J., & Sanfey, A.G. (2020). Stable distribution of reciprocity motives in a population. Scientific Reports, 10, 18164. https://doi.org/10.1038/s41598-020-74818-y

Meijs, E., Klaassen, F.H., Bokeria, L., van Gaal, S., & de Lange, F.P. (2018). Cue predictability does not modulate bottom-up attentional capture. Royal Society Open Science, 5:180524. https://dx.doi.org/10.1098/rsos.180524