Alexandra Münster completed her Ph.D. on “Neurobiological studies on the role of the orbitofrontal cortex in action control“. Congratulations!

Humans and animals flexibly select learned actions in order to achieve goals, such as a specific food reward. This ability is essential for survival in a constantly changing environment. A fundamental challenge of neuroscience is to understand the neurobiological basis of action selection. Action selection depends on a brain circuit that stores the learned associations between actions and their respective positive or negative consequences. Importantly, action selection also depends on another circuit that controls whether or not a learned action is actually initiated in a given situation as well as the vigor of action. The willingness to act (motivation) controlled by this latter circuit depends on hunger and thirst, among others. In her Ph.D. thesis, Alexandra Münster used a rodent model to investigate the role of the orbitofrontal cortex, a part of the frontal cortex, in controlling motivation. Her work provides the following new findings: (1) There is functional microheterogeneity in the orbitofrontal cortex with regard to action control, i.e., one area of the orbitofrontal cortex controls motivation, while another area controls cognitive functions. (2) The neurotransmitter dopamine supports motivational control by the orbitofrontal cortex. (3) The orbitofrontal cortex is part of the brain circuit that controls motivation thereby interacting in particular with a specific area of the midbrain, the ventral tegmental area. (4) Activation of the orbitofrontal cortex inhibits motivation and vice versa. By context-dependently controlling the motivation to act, the orbitofrontal cortex may help conserving the often limited metabolic resources of an organism and thus support biological fitness and survival. Overall, Alexandra Münster's findings improve our understanding of the neurobiological and neurochemical basis of motivation and are also of clinical interest. This is because numerous psychiatric illnesses, such as depression, are characterized by dysfunctions of the orbitofrontal cortex as well as altered motivation.