Scientists reported today (April 27, 2026) that the brain is more mechanically connected to the body than previously realized. natural neuroscience. Through studies using mice and simulations, researchers have discovered a potential biological mechanism underlying why exercise is thought to be good for brain health. Contractions in the abdomen squeeze blood vessels connected to the spinal cord and brain, allowing organs to move gently within the skull.
This shaking allows surrounding cerebrospinal fluid to flow more easily over the brain, potentially washing away neurological waste that can cause problems with brain function.
Patrick Drew, a professor of engineering science and mechanics, neurosurgery, biology and biomedical engineering at Penn State, said the study builds on previous research detailing how sleep and neuron loss affect when and how cerebrospinal fluid flows through the brain.
Our research explains how just moving around acts as an important physiological mechanism that promotes brain health. ”
Patrick Drew, corresponding author, Professor of Engineering Science and Mechanics, Penn State University
He continued, “In this study, we found that when the abdominal muscles contract, like a hydraulic system, they force blood from the abdomen into the spinal cord, putting pressure on the brain and causing it to move.” In the simulation, this gentle brain movement was shown to cause fluid flow in and around the brain. “Moving fluids in the brain is thought to be important for waste removal and preventing neurodegenerative diseases. Our research shows that a little movement is good, and could be another reason why exercise is good for the brain.” health. ”
Drew, who also holds the title of deputy director of the Huck Institute for Life Sciences, explained how pumps create pressure that drives fluid flow within hydraulic systems. In this case, the pump is an abdominal contraction that can be as light as the tension before sitting or taking a step. The contractions put pressure on the spinal venous plexus, a network of veins that connect the abdominal and spinal cavities, causing the brain to move.
The researchers used two advanced imaging techniques to visualize the process of mouse movement. One is two-photon microscopy, which allows high-resolution imaging of living tissues, and the other is micro-computed tomography, which allows high-resolution 3D examination of whole organs. They observed changes in the brain in the moments before the mice moved, but immediately after tightening their abdominal muscles, they had to move their bodies even more.
To confirm that it was abdominal contractions, and not other movements, that acted as a pump, the researchers applied gentle, controlled pressure to the abdomens of lightly anesthetized mice. When the mice were subjected to no movement other than local mechanical pressure, which was lower than that experienced by humans with blood pressure cuffs, the mice’s brains changed.
“Importantly, the brain began to return to its baseline position as soon as the abdominal pressure was released,” Drew said. “This suggests that abdominal pressure can rapidly and significantly change the position of the brain within the skull.”
Now that we have confirmed the link between abdominal contractions and brain movement, the next step is to understand how fluid moves in the brain and whether brain movement can trigger fluid flow, Drew said. However, until now, there were no existing imaging techniques to visualize such rapid and subtle dynamics of fluid flow.
“Fortunately, an interdisciplinary team at Penn State was able to develop these techniques, including conducting live mouse imaging experiments and creating computer simulations of fluid motion,” Drew said. “This combination of expertise is critical to understanding these types of complex systems and how they impact health.”
Francesco Costanzo, professor of engineering science and mechanics, biomedical engineering, mechanical engineering and mathematics, led the computational modeling.
“Modeling fluid flow in and around the brain poses unique challenges because there are simultaneous, independent movements, as well as time-dependent and coupled movements. To account for all of this, we need to take into account the special physics that occur every time a fluid particle crosses one of the many membranes in the brain,” said Costanzo. “So we simplified it. The brain is sponge-like in the sense that it has a soft skeleton and fluids can move through it.”
Costanzo explained that by simplifying the shape of the brain to the shape of a sponge, researchers can model how fluids flow within structures with various spaces, such as the brain’s wrinkles or the pores of a sponge.
“Continuing with the idea of the brain as a sponge, we also thought of the brain as a dirty sponge. How do you clean a dirty sponge?” Costanzo asked. “You turn on the faucet and squeeze it out. In our simulations, we were able to understand how abdominal contractions, which move the brain, induce fluid flow throughout the brain and help remove waste.”
Professor Drew stressed that although further research is needed to fully understand the effects in humans, this study suggests that physical movement may help circulate cerebrospinal fluid around and within the brain, removing waste products and protecting against neurodegenerative diseases associated with waste accumulation.
“These kinds of movements are very small; they occur when you walk, contract your abdominal muscles, and do other physical actions. They can make a big difference to your brain health,” Drew says.
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pennsylvania state university
Reference magazines:
Gerborg, C.S. others (2026) Brain movements are driven by mechanical connections with the abdomen. natural neuroscience. DOI: 10.1038/s41593-026-02279-z. https://www.nature.com/articles/s41593-026-02279-z.
