The app is now being used in several ongoing studies involving patients with chronic back pain and fibromyalgia. It is minimalist in design and purpose, and even though it doesn’t offer solutions or advice, many patients quickly saw value in the app’s tracking function. In one survey of 77 participants, 91% of users said they found data to be useful in helping them develop insights into their pain. Many also appreciated having an objective record to share with clinicians — as one participant put it, “It's the only way I can show my doctor what is going on with my pain.”

“Chronic pain patients take, on average, six to 10 medications a day,” Petzschner said. “By tracking their pain, they can learn what’s not working, which can lead to trying other types of therapy that might be more effective.”

At the same time, the researchers are collecting valuable data. Petzschner’s team has built one of the largest high-density data sets following chronic pain trajectories over multiple months. This subjective reporting from patients, Petzschner said, shows the effects of treatments over time. And one way that her research team is using the data is combining it with machine learning models to predict future pain outcomes.

“A key area we’re moving into is understanding to what degree expectations of pain and treatment efficacy predict short- and long-term pain,” Petzschner said. “And how can we understand these predictors now to actually provide better care?”

Building on these insights, Petzschner’s team recently spun the project out into a startup company led by Brown postdoctoral research associate Chloe Gunsilius. The new venture aims to translate the research into a clinical tool that, with the help of artificial intelligence, offers personalized analytics and guidance for people living with chronic pain — extending the mission of using brain-based science to improve well-being beyond the research setting, she said.

The birth of embodied brain research

It all started with anxiety, Petzschner said. Not hers, but the concept in general.

At Ludwig Maximilians University in Munich, Petzschner earned a Ph.D. in systemic neuroscience, which is the study of neural circuits and systems. She focused on human perception of space and time.

“I started to think about what happens when people perceive the world differently than others,” she said. “Could those changes in perception be linked to mental illness? Could subtle differences in how we interpret sensory information become symptoms?”

This curiosity led to a postdoctoral position in the relatively new field of computational psychiatry, which involves applying mathematical tools to cognitive problems. Petzschner homed in on how people’s perceptions of control — the sense of being able to influence outcomes — shape behaviors in gambling and OCD.

 “I thought a lot about what is causing the feeling component of OCD — the anxiety,” Petzschner said. “You can’t really explain anxiety without understanding where emotions and feelings come from. And you can’t do that without considering the body. Anxiety isn’t just in the mind; it’s created by the body’s internal rhythms — the racing heart, the breathlessness — interacting with what’s happening around us. That’s when I realized there’s no way to understand health and well-being without understanding brain–body interactions.”

The brain’s perception of signals from the body, known as interoception, has been the focus of Petzschner’s work even before she arrived at Brown in 2021. She has been working to understand how disruptions in interoception can influence emotion, decision-making and well-being.

In a series of ongoing studies, Petzschner and her team are analyzing how people process their cardiac rhythms. In a typical experiment, participants listen to tones that are either in sync or out of sync with their heartbeat. Using non-invasive brain imaging techniques including fMRI and EEG, the researchers measure how and where in the brain these internal and external signals are integrated — revealing how the brain links cardiac and auditory inputs. Petzschner hopes that understanding this integration will shed light on how disruptions in brain–body communication contribute to conditions such as anxiety and depression.

Heady concepts, clinical applications

The heartbeat experiments are typical of the work done by Ph.D. students and postdoctoral researchers in Petzschner’s lab, whose interests span cognitive science, neuroscience, computer science, math and medicine. Members of the team are running experiments at the Carney Institute nearly every day of the week.

Each session usually lasts for several hours, during which participants complete computer-based behavioral tasks — “little games,” Petzschner calls them — while their brain activity is recorded using EEG or fMRI. The team then applies computational models of learning, decision-making and perception to interpret the data.

“We try to infer from the way people play what their strategy was so that we can better understand why people make the choices they do,” she said.

The team recently studied how decision-making is altered in chronic pain. In results submitted for peer review and published in pre-print format online, they found that chronic pain can alter the decision-making process in patients. The results, Petzschner said, could explain why some patients continue to avoid certain movements or activities even after their damaged tissue has healed.

“This type of finding could ultimately help clinicians refine treatment plans for people with chronic pain — by addressing not just symptoms, but the underlying learning and decision-making processes that sustain them,” she said.

That’s what excites Petzschner about this work: the cerebral concepts she studies have real-world relevance and clinical application.

“At the university, we often study problems that can seem abstract or far removed from daily life,” she said. “But for me, the goal is always to bring those ideas back to people — to help patients live better in their own bodies. Every experiment we run is meant to move us closer to that goal.”