DCCN Colloquium by Prof. Dr. Tobias H. Donner

Cognitive behavior rapidly adapts to changing environmental contexts, a flexibility that distinguishes it from reflex behaviors. I propose that this flexibility results from the rapid reconfiguration of highly selective and distributed cortical networks that implement the sensory-motor transformations required by a given task context. This reconfiguration is enabled by plasticity mechanisms controlled by modulatory neurotransmitters that are released from the brainstem. To support these claims, I will present evidence from human behavioral, pupillometric, 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 input or behavioral choice), across a large set of cortical regions and relate these cortical interactions to the dynamics of (proxies of) brainstem modulatory activity. We find that the structure of content-specific cortical interactions is continually reconfigured in a context-dependent manner. These changes in cortical interactions are predicted by brainstem modulatory activity. The latter, in turn, is specifically recruited by changes in the environment, a process that is impaired in older individuals and in younger ones at risk of developing psychosis. Our results open a new window on the dynamic sculpting of large-scale cortical networks for adaptive behavior by the brainstem, and its impairment in mental disorders.