Prof. Dr. Tobias H. Donner
Cognitive behavior rapidly adapts to changing environmental contexts. This flexibility distinguishes cognitive behavior from reflexes. I propose that this flexibility results from the rapid reconfiguration of distributed cortical networks that implement the transformations required by a given task and context. This reconfiguration is enabled by rapid plasticity mechanisms that are controlled by neuromodulators released from the brainstem. To support these claims, I will present human MEG and fMRI experiments, in which we systematically manipulate context variables, such as task rules or environmental volatility. We quantify the resulting changes in content-specific neural interactions (e.g., selective for sensory evidence or behavioral choice), across a large set of cortical regions. We relate these cortical interactions to the dynamics of (proxies of) brainstem modulatory activity. This approach reveals that the structure of cortical interactions changes in a context-dependent manner. These changes are predicted by brainstem modulatory activity, which, in turn, tracks hidden changes in the environment. Preliminary results indicate that the cognitive recruitment of modulatory brainstem systems is impaired in individuals with a high risk of developing psychosis. Our results open a new window on the dynamic brainstem sculpting of large-scale cortical networks for flexible cognitive behavior. I speculate that this sculpting goes awry in many mental disorders.
