Department of
Psychological and Brain Sciences

“Sometimes we wish we could do everything at once,” says newly arrived PBS assistant professor and alumna Alexandra Moussa-Tooks (Ph.D. ‘21).

She is explaining her boundless enthusiasm for all aspects of faculty life in PBS and the Clinical Science Program – and her dismay that she must wait for a future date to take up some of them: From research, writing, teaching, and conducting a clinical workshop, all of which she is currently doing, to the practice of therapy, and yes, even taking on administrative roles, for which she will have to wait.

Not to mention her active engagement in addressing gender and racial biases as they exist both broadly in the field and in clinical practices and treatments. A recent publication on ways to improve retention of underrepresented minorities in science and medicine and an upcoming virtual workshop on integrating experiences of systemic racism into a clinician’s understanding of psychosis in Black clients take on these issues point blank.

Moussa-Tooks first arrived at IU in 2015 as a graduate student in the lab of Professor Bill Hetrick, completing a dual Ph.D. in psychology and neuroscience. After serving as a postdoctoral fellow in the Vanderbilt University Medical Center Department of Psychiatry and Behavioral Sciences, she joined the Vanderbilt faculty as an assistant professor of Psychiatry and Behavioral Sciences. This past fall she returned to Bloomington as a tenure-track faculty member.

Understanding psychosis from the ground up

Moussa-Tooks’ research explores the continuum between motor symptoms of psychosis and “higher order” symptoms like cognitive dysfunction. In fact, she sees those motor symptoms, which include disturbances in gait or posture and the timing and coordination of movements, as the potential source of important clues to the more elusive disturbances of complex cognitive processes, and even more complex symptoms like paranoid delusions and hallucinations.

As she describes it, “The primary work in our lab is looking at these motor symptoms in psychotic disorders and trying to pinpoint where the deficit comes from. Is it a problem with their motor mechanical function, with timing or the ability to generate a model of the world and understand how to move around in it?”

She leans toward the notion “that this deficit is in generating a model of the world and being unable to update it.” And this ability to generate and update a model of the world applies as much to cognitive activities like making decisions or forming beliefs as it does to physical movement like reaching for a cup of coffee.

 

“The way we can think about it is that the same processes that allow us to move are the same processes that allow us to think about the world and process other types of information. We can really easily get at the motor system, at someone’s inability to grasp something, but it is a lot harder to ask someone who has a very fixed belief why they have that belief and why they’re not able to update it.” Also compelling is that the motor symptoms are often the first symptoms of psychosis to appear in a patient’s childhood or adolescence before the onset of other psychosis symptoms.

In the lab she hopes to figure out the details of this process of generating models of the world and correcting them if there’s an error, how this process can go wrong and what brain regions are involved in it.

One of those brain regions, the cerebellum—which accounts for one eighth of the brain's volume, yet contains up to 80 percent of its neurons—stands out as a key player. Formerly believed to play a role solely in the coordination of motor activities, it is now believed to also play a role in the fluidity of thought and other cognitive processes.

Moussa-Tooks first became interested in the role of the cerebellum as a student in PBS Professor Bill Hetrick's lab, particularly its newly discovered involvement in higher order functions like learning and social processes. Then, she says, “as I got more into my research, the motor aspect, which we traditionally think of as the cerebellum’s function, felt like a huge inroad that is easier to measure and access.”

Art lessons

Moussa-Tooks traces her interest in psychotic disorders back to her childhood in Chicago. Her parents would enroll her in the free art classes for children at the Art Institute of Chicago and these classes opened her eyes to how differently we each perceive and interpret the world. When the class was asked to sketch a common artwork in the museum, everyone’s versions would be vastly different. And while these differences are fully expected in an art class, she continued to wonder how it is we construct such different versions of the world, some of which are considered normal and others abnormal.

Through her work in the lab, she seems to be finding some of the answers. And, she believes that someday these answers will help those whose models of the world have failed them.