The human brain is much softer than we have long assumed. In fact, it behaves almost like a fluid. This is shown by new MRI research by Marius Burman Ingeberg, who will defend his PhD on this topic on May 1. The findings challenge our understanding of the brain and may help us better understand brain disorders.
Every second, the heart pumps blood to the brain. This causes blood vessels and surrounding brain tissue to displace ever so slightly. “These movements are extremely small,” says PhD candidate Marius Burman Ingeberg. “But if you scaled the brain up to the size of the Earth, these movements would be as large as Mount Everest.”
Together with associate professor Jaco Zwanenburg from UMC Utrecht, he captured these subtle displacements in unprecedented detail using a new MRI technique.
This image shows, in an exaggerated way, how the brain moves with the blood flow from each heartbeat. Video created by Ayodeji Adams, a former member of the Zwanenburg research group.
By measuring these movements and combining them with computational models, the researchers were also able to determine how stiff different regions of the brain are.
The results were striking: the brain is about a hundred times softer than previously thought and behaves almost like a fluid. “At first, we thought we had made a mistake,” says Burman. “But repeated measurement, additional tests on the computer models, and similar findings from other independent research groups confirmed the result.”
According to the researchers, this finding aligns well with other functions of our brain tissue . “Nutrients continuously flow into the brain, while waste products are removed. In softer tissue, these fluids can move more easily.”
The discovery may help improve our understanding of brain disorders. “After a stroke, we see that parts of the brain can swell rapidly,” says Zwanenburg. “If we better understand the properties of brain tissue, we can also better explain what happens in these situations.”
The research may also help answer open questions about the brain, such as the role of the heartbeat during sleep. “The brain may become even softer when the heart rate is lower,” says Burman. “That could help explain why waste products are cleared more efficiently at night.”
According to the researchers, this finding is only the first step. “Before we can answer these questions, we first need to perform further studies in patients and during sleep,” says Marius. “But one thing is clear: this discovery fundamentally changes how we view the brain.”
Every second, the heart pumps blood to the brain. This causes blood vessels to expand slightly and the surrounding brain tissue to move subtly.
The researchers mapped these tiny movements using a new technique: iMRE (intrinsic Magnetic Resonance Elastography). This method uses a powerful 7 tesla MRI scanner.
With this technique, researchers can observe how brain tissue naturally moves with the heartbeat. This provides a more realistic picture of brain properties than previous methods.
By measuring these movements and combining them with computational models, the researchers can determine how stiff different parts of the brain are. The less the tissue deforms, the stiffer it is. This results in a detailed map of how soft or firm different regions of the brain are.
