"Trapped in Thought: Understanding Depression and Trauma Through the Brain"
Speaker: Carissa Philippi, PhD
Associate Professor of Psychological Sciences, University of Missouri-St. Louis
Date: November 18, 2025, noon-1 p.m.
Location: Millennium Student Center, Century Room B
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Description
Getting lost in thought is a universal human experience. In fact, adults spend nearly half their waking hours engaged in “self-related” processing, whether it be daydreaming, reflecting, planning, or empathizing. Scientists call this mind wandering. In its healthy form, it helps mediate social and emotional functioning; however, it can become disrupted in several psychiatric diagnoses. For example, in depression and post-traumatic stress disorder, mind wandering can shift to rumination. That’s where thoughts become stuck in persistent, uncontrollable loops of negative self-talk.
Carissa Philippi, a neuroscientist and associate professor at the University of Missouri-St. Louis, studies this phenomenon. Specifically, her research investigates the neural mechanisms of self-related thought. Using fMRI brain imaging technology, Philippi's team observes brain activity while participants rest inside a scanner, allowing their minds to drift freely. These moments reveal the workings of the brain’s default mode network—an interconnected system of brain regions that activate when we think about ourselves—and how it functions differently in healthy versus dysfunctional states.
Philippi’s work demonstrates that mind wandering has a clear biological signature. She explains that in states of negative self-talk, two key things happen in the brain. First, the brain’s default network becomes hyperactive, increasing the frequency and intensity of the negative thoughts. Second, the pathways that normally allow us to tune out this internal chatter and focus elsewhere are impaired. Philippi explains that this combination underlies rumination by “causing us to stick internally.”
Philippi points to promising research using games like Tetris to reduce flashbacks in individuals with PTSD. “There’s some work showing that if you get people to play video games, you can interrupt some of that negative self-talk and reduce rumination,” she says.
Ultimately, Philippi’s research bridges everyday experience and cutting-edge science. The goal? To translate insights about the wandering mind into practical tools that improve mental health.
“Ideally, we would give individuals a brain scan before they start therapy,” says Philippi. “By analyzing brain structure and function alongside behavioral data, we could determine which treatment a person is most likely to benefit from.” This approach points toward a future where mental health care is guided not just by symptoms, but by the unique wiring of each individual's brain.
About the Speaker
Dr. Carissa L. Philippi earned her Ph.D. in Neuroscience from the University of Iowa in 2011. She then completed a four-year postdoctoral fellowship at the University of Wisconsin-Madison where she conducted neuroimaging (i.e., resting-state fMRI) and behavioral studies on self-related thought in brain injured patients, psychiatric patient populations, and psychopathic prison inmates.
Broadly, her research aims to understand the brain circuits underlying self-related processes, in both the healthy and dysfunctional brain (e.g., psychiatric illness). Self-related processing is essential for normal social and emotional functioning. For example, self-reflection helps individuals to generate social emotions (e.g., guilt) necessary for upholding social norms and forming social relationships. By contrast, a number of psychiatric and neurological conditions are associated with alterations in self-processing (i.e., excessive rumination in depression or diminished self-reflection in patients with medial prefrontal cortex damage) that can have detrimental consequences for our overall well-being.
Dr. Philippi's research involves fMRI, psychophysiology, and a variety of behavioral paradigms to study different types of self-related processing—such as self-reflection and self-agency—with healthy subjects and psychiatric patient populations.
Thanks to STEMCELL Science News for their media partnership.
About the Discovery Series
The NextGen Precision Health Discovery Series provides learning opportunities for UM System faculty and staff across disciplines, the statewide community and our other partners to learn about the scope of precision health research and identify potential collaborative opportunities. The series consists of monthly lectures geared toward a broad multidisciplinary audience so all can participate and appreciate the spectrum of precision health efforts.
For questions about this event or any others in the Discovery Series, please reach out to Mackenzie Lynch.
Reviewed 2025-10-21