Neurobiology of Sensorimotor Decision Making
Given the vast number of behavioral options that are usually available in an everyday life situation, how do we - and thus our brain - decide which option to go for? How is the selected behavior planned and optimized through learning? And how does our brain predict the sensory consequences of that behavior, allowing us to perceptually distinguish sensory events that we have caused from externally produced sensations? Using psychophysical techniques and functional imaging studies, my laboratory aims to give answers to these questions. Moreover, we try to clarify whether specific symptoms of neurological and psychiatric diseases might reflect a disorder of these cognitive processes under investigation.

To isolate the brain processes that underlie the selection and planning of goal directed behavior we resort to functional magnetic resonance imaging (fMRI) during delayed response tasks, which allow temporally separating planning and decision processes from representations of both sensory context information and motor responses. Using this technique we could demonstrate that, already at the level of human posterior parietal cortex, plans for upcoming actions are encoded and modulated by decision variables such as reward and punishment. Based on these findings we currently test the idea that posterior parietal cortex might be a crucial substrate for sensorimotor decision making. (Read more about our ongoing research)

A second major line of research in the lab tries to explain mechanisms of our ability to attribute causal agency to the sensory consequences of one's behavior and investigates disorders of this "sense of agency" in neuropsychiatric diseases. For instance, schizophrenia patients often form delusional beliefs that "external forces" make them speak or move, the common denominator being that self-produced sensory events are misinterpreted as externally caused. We have been able to demonstrate that the strength of these symptoms is explained by patient's inability to predict the sensory consequences of their own actions. Using such sensory predictions, a healthy subject can isolate the sensory information for which she is responsible for. The same mechanism also allows healthy individuals to attribute causal agency to sensorimotor error information, enabling one to specifically correct those mistakes for which one is being responsible. What is the neural substrate of these sensory predictions? We already identified the cerebellum which enables one to learn and optimize sensory predictions. Currently we try to reveal the neural underpinnings that generate sensory predictions in the first place. (Read more about our ongoing research)