Gittis studies neuroscience behind compulsive disorders

Gittis received a grant to study compulsive behavior. (credit: Aryn Gittis) Gittis received a grant to study compulsive behavior. (credit: Aryn Gittis)

Many Carnegie Mellon researchers are currently involved in cutting-edge research focused on understanding the complex ways in which the brain functions. Aryn Gittis, an assistant professor in biological sciences, as well as a member of the joint Carnegie Mellon and University of Pittsburgh Center for the Neural Basis of Cognition, has received a two-year NARSAD Young Investigator Grant from the Brain and Behavior Research Foundation, which she will use to study the mechanisms behind compulsive behavior.

Gittis initially began working with a part of the brain called the basal ganglia — which is located in the base of the forebrain and is primarily associated with action selection — as a post doctoral researcher at the Gladstone Institute of Neurological Disease. “When I started my post doc, I wanted to start studying the basal ganglia because it was relevant for so many different diseases,” Gittis said. “It was almost serendipitous that I became interested in compulsive behavior because I found some genetic tools to study different populations of neurons in a part of the basal ganglia called the globus pallidus.”

Gittis discovered that when certain populations of neurons in mice were activated, the mice became hyperactive. Along with other research, this finding suggested that the globus pallidus is involved in many compulsive behaviors, such as attention deficit hyperactivity disorder, obsessive-compulsive disorder, and Tourette’s syndrome. “The globus pallidus seems to be a site of convergence for a lot of different pathways that have all been implicated in compulsive behavior,” explained Gittis.

The NARSAD Young Investigator Grant is given to early career scientists who intend to pursue the study of brain and behavior disorders. Gittis and her team, including post doctoral fellow Amelie Soumier, first-year biology major Brandon Rogowski, and senior biology and psychology double major Nick Zuniga, will use the NARSAD grant to conduct follow-up research on her previous findings about the globus pallidus.

In particular, Gittis notes that Parkinson’s disease is a main focus of her research. They will use optogenetics — a technique which uses light to control neurons in the brain — to determine how behavior changes when cells in the globus pallidus are activated or deactivated. “It’s a way of turning on and off genetically distinct neural circuits so that we are able to see how behavior changes when these [circuits] are on or off,” Gittis said.

In this way, they will be able to determine which populations of neurons are involved in compulsive behavior.

“We want to figure out if the increase in movement we’re seeing is due to general hyperactivity of neural circuits, or if it’s due to the inability of animals to suppress movements, which would be more like a compulsive behavior,” said Gittis. “We want to expand the behavioral tests that we’ve tested, and in addition to turning cells on, we want to also turn cells off.”

Gittis’ research has the potential to have a large impact in the world of neuroscience. “There’s a huge need in neuroscience to understand how all these different classes of neurons we’ve identified interact with one another and how they are activated — both in normal behavior and in disease states,” explained Gittis. But the research could also have important pharmacological effects. “A lot of the medications we currently use are medications that were discovered decades ago, and we still don’t really understand how they work,” Gittis said. “The hope is that by being able to delve into neural circuits at the cell type level and identify unique classes of neurons, we can then figure out ways to pharmacologically, selectively target those cells.”

Gittis also noted that the way neurons function is an important stepping stone on the way to the development of treatments: “Eventually it will lead to drug development ... but we first need to understand how the neurons work and how they interact with one another.”

This research could help scientists understand the mechanisms behind brain and neuron activity. Once the mechanisms are more clearly understood, researchers will be able to more easily develop new and more effective treatments and therapies to counteract a variety of neurological disorders.