Research Interests
1. Using real-time fMRI neurofeedback to non-invasively drive the dopamine system in humans
One line of my research focuses on using real-time fMRI (rt-fMRI) methods to drive the dopaminergic midbrain – a region critical for reward processing, motivation, learning and memory. Nearly all research examining the dopamine system has used external reinforcers to drive this system (e.g., food, money). However, we know individuals motivate themselves on a daily basis without external reinforcers. My colleagues and I pioneered a novel method for activating the brain non-invasively called cognitive neurostimulation. Cognitive neurostimulation relies on using thoughts and imagery to activate the brain, rather than on pharmacology or invasive techniques. We demonstrated that healthy adults can self-activate the dopaminergic midbrain in the absence of external rewards, using only internally generated thoughts and imagery. We are excited to follow up on this line of work both by asking basic science questions about the dopamine system and exploring the use of this technique as a potential clinical intervention for a variety of diseases with abnormal dopamine function.
2. Improving therapeutic efficacy using real-time fMRI neurofeedback
Another line of research examines how we can use rt-fMRI tools to improve the efficacy of therapy. Therapy (e.g., cognitive behavioral therapy) is one of the most effective treatments for depression. While effective for many patients, others see little or no benefit. One of the challenges of therapy is that it is slow, effortful, and provides little immediate feedback of success. We had the idea of combining therapeutic strategy use (e.g., what would Mom do in this situation?) with rt-fMRI neurofeedback in order to give patients immediate feedback about how their strategies learned in therapy change the brain. Showing individuals how their brain activity changed following strategy use was a very empowering experience for participants and predicted future behavior. The neurofeedback they received after using their strategies correlated not only with how effective they rated their strategies on the scan day, but also predicted feelings of strategy efficacy one month following the scan session. This points to the ability of a single scan session to increase strategy use and feelings of therapy efficacy. We are excited to follow up on this line of work examining if combining therapy with rt-fMRI neurofeedback will increase strategy use and ultimately improve clinical symptoms.
3. Characterizing the influence of reward and motivation on learning and memory in humans
Much of my research has focused on neuroimaging of the mesolimbic dopamine system in humans. While the majority of studies in the field use extrinsic rewards to drive this system (e.g., food, money), I have utilized both extrinsic as well as intrinsic ways of activating this system. One line of research has characterized extrinsic influences (reward) on learning and memory. I have been particularly interested in reward’s influence on multiple brain regions within the mesolimbic dopamine system. I developed probabilistic reward learning tasks that promote either striatal dependent or hippocampal dependent learning and have examined the interactions of these regions during learning and memory. My work demonstrated that the striatum and hippocampus work in parallel to promote learning and memory. I have also examined intrinsic ways of eliciting dopamine activation (see section I) and aim to extend this work to examine the downstream effects of self-activation of midbrain dopamine on cognition.