Human beings are creatures of habit: from driving a car to brushing our teeth, many actions we take on a day-to-day basis are rooted in a biochemical feedback loop. Talia Lerner, PhD, assistant professor of Physiology, has spent much of the last decade studying the neurological basis for habit formation, hoping to illuminate brain circuitry that could improve treatments for psychiatric diseases such as obsessive-compulsive disorder or substance use disorders. She joined Feinberg in 2017 after completing a postdoctoral fellowship at Stanford University.
Read a Q&A with Lerner below.
What are your research interests?
I’m very interested in habit formation; the process by which behavior becomes automatic. Habit formation is an essential survival strategy in a complex world. It’s also an interesting behavior because it sits at the interface between reward learning circuits and motor circuits. Feedback, in the form of rewards and punishments, is required in the initial stages of learning a new task, but as actions are repeated they are taken over by motor circuits — streamlined, stereotyped and de-coupled from feedback, leading to inflexible behavior.
My lab wants to know which neural circuits are responsible for this complex process of habit formation. How do neural circuits weigh the costs and benefits of automaticity and use feedback from the environment to regulate the formation of habits over time?
We already have some insight into this: We know that habit formation requires the striatum, the input nucleus of the basal ganglia, as well as dopamine inputs to the striatum from the substantia nigra pars compacta (SNc). Previously, I identified two parallel SNc dopamine neuron subpopulations projecting to the dorsomedial striatum and dorsolateral striatum, publishing these findings in the journal Cell. These populations differ in their biophysical properties, input wiring and natural activity patterns during free behavior.
They are also interconnected with each other, suggesting possible routes of information transfer during habit formation. To test our hypotheses, my lab is examining how the properties of dopamine neuron subpopulations — and their interconnections with the striatum — change with habit formation, and how forces such as stress and drug exposure alter the course of learning by acting on these circuits.
What is the ultimate goal of your research?
My work provides an important foundation for future studies of the roles that habits play in a range of psychiatric diseases, including obsessive-compulsive disorder and drug addiction. As our studies progress, they will provide insight into the circuit-level etiology of human mental disorders and help us to design circuit-based therapies.
My lab is also very interested in individual differences in circuit structure that might predispose one towards disease. Ultimately, I think my studies could help provide information for risk screening as well as for the selection of personalized treatment plans in human patients.
What do you enjoy about teaching and mentoring young scientists in the lab?
Young scientists bring new energy to a project; when a person is new to a field, they often can be their most creative. It’s my job and privilege to channel that creativity into a concrete project and to make sure it fits into the bigger picture of what the lab is trying to accomplish.
I’m also proud to be a female role model in science and to model other behaviors that I’d like to see in the next generation of scientists, such as openness and inclusivity. I care a lot about diversity in science and about bringing new voices to the table. I hope to use my teaching and mentoring capacities at Northwestern to support young scientists from a variety of backgrounds.
How is your research funded?
My research program so far has been generously funded by the National Institute of Mental Health and by the Brain & Behavior Research Foundation. As a new investigator, I’m also grateful for support from Northwestern and from the Searle Leadership Fund.
What resources at Northwestern have been helpful for your research?
Northwestern has been an incredibly supportive environment in which to start my research program. In particular, the Center for Advanced Microscopy has been crucial for allowing my lab to image and map whole-brain dopamine circuits. We’ve also been support by Quest, the high-performance computing cluster, and by many, many helpful colleagues both in Chicago and Evanston.