The science of slumber
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One of the body’s most important processes happens when we’re at rest, says Danlei Chen. “As we sleep, cerebrospinal fluid gets pushed in and out of the brain in waves — with the rhythm of your heartbeat and breathing — to wash out metabolic waste like toxins,” she explains. “If this cleaning system breaks down, it can give rise to neurodegenerative diseases like Alzheimer’s and Parkinson’s.” The mechanisms powering this laundering process are still opaque. If made clear, understanding this system could expand a growing body of knowledge on the brain-body connection — a field still riddled with gaps.
Sleep tracking
Chen is intent on filling those gaps as a K. Lisa Yang Brain-Body Center Postdoctoral Fellow at MIT and researcher in Laura Lewis’s lab in the Research Laboratory of Electronics. She seeks to interpret the cross talk that occurs between the mind and body during sleep, a particularly large void that scientists have stumbled over. “Most brain imaging studies on sleep focus only on neural activity,” she says. “But with our new paradigm — one that can track cerebrospinal fluid alongside blood flow — we can better understand how the brain works with the rest of the body to support essential functions and maintain health.”
That approach, she says, requires ultra-high-resolution imaging since the spaces in the brain through which cerebrospinal fluid flows are so small. Fortunately, the Athinoula A. Martinos Center for Biomedical Imaging at Massachusetts General Hospital houses a powerful magnetic resonance imaging (MRI) scanner. This 7-Tesla scanner can deliver more than twice the resolution of typical 3-Tesla MRI machine, giving scientists a precise view of the brain’s tiny structures and subtle fluid dynamics. “A scanner with this level of field strength is still relatively rare,” Chen notes. “MRI studies mostly focus on changes in blood flow, which is used to track neural activity. We are using our innovative imaging method that captures two complementary ‘views’ of the same data, helping us separate blood-related signals from signals linked to cerebrospinal fluid.”
Pinpointing the physiological features that support healthy sleep could broaden scientists’ understanding of how the sleeping brain supports long-term wellness.
A bridge between two fields
Originally on track to major in finance at the University of Rochester, Chen became fascinated by the human brain, inspiring her to study neuroscience instead. She pursued her PhD in psychology at Northeastern University to decode how the brain stem contributes to both autonomic functions, like breathing, and cognitive functions, like decision-making. “This work familiarized me with the system-wide connections between the brain and the body, and how their interactions give rise to the human mind,” she says.
Extending this line of research at the Yang Tan Collective, Chen aims to help merge two fields that have long remained siloed. “Historically, ‘brain’ people have studied the brain, and ‘body’ people have studied the body. I think the field is moving toward a framework that encompasses both areas. To me, this is not just an important approach — it’s a necessary one,” she says.
When not in the lab, Chen enjoys knitting; playing tennis; and hiking, often taking pictures of the mushrooms she finds during those treks. “I’m drawn to their whimsical shapes and colors, and to the sense of small adventure and discovery they bring,” she says.
Chen adds that the Yang Tan Collective forms an environment ripe for scientific progress. “You don’t really have to explain yourself much for people to understand you and move the research forward — it’s being moved forward every day, at every moment,” she says. “And because everybody’s moving forward, it pushes you in the right direction as well.”
