dr. M.G.A. van Holstein (Mieke)

An animal will look for food because it anticipates this behavior to result in a reward (the food). In order to obtain this reward it might not be very adaptive to simply chase stimuli that previously signaled the presence of this reward, but it must flexibly adapt to changes in its environment and respond accordingly. This flexible adaptation requires higher-order cognition or executive functioning and motivation needs to be able to affect cognition.

Motivational and cognitive processes have been studied quite extensively, but less is known about the interaction between the two and how the brain regions involved in these processes interact. A better understanding about these processes can shed light on the mechanisms underlying several neuropsychiatric disorders, such as Attention Deficit Hyperactivity Disorder (ADHD) and addiction.

My research focuses on the way motivation can affect cognition and the role of dopamine in this interaction. We know that brain regions don't act in isolation, but that distinct parts of the prefrontal cortex connect to distinct parts of the striatum. These cortico-striatal loops subserve distinct processes. I am particularly interested in the motivational and cognitive loop and in the communication between them.

I predict that information will flow from the motivational loop to the cognitive loop, and that dopamine plays an important role in this communication. I use brain imaging (functional magnetic resonance imaging; fMRI) to look at brain activity, brain stimulation (transcranial magnetic stimulation; TMS) to look at the consequences of perturbing one of the loops and genetics (dopamine genes; DAT1/SLC6A3) and pharmacology (bromocriptine, sulpiride and methylphenidate) to look at the effects of dopamine. In addition, I compared the effect of motivation on cognition in healthy adults and adults with ADHD and look at the effect of age on this interaction.