The brain is one of the body’s most energy-intensive organs, and a new study by Ben-Gurion University of the Negev (BGU) suggests a key brain structure plays a crucial role in conserving that energy. Researchers found that myelin—the protective sheath surrounding nerve fibers—functions primarily as an energy-saving system rather than simply accelerating neural communication, cutting the energy cost of brain signaling by about 50%.

The findings could advance research into multiple sclerosis (MS) and other myelin-related disorders by shedding light on how myelin loss disrupts both nerve signaling and the brain’s energy balance. The research may also inform future treatments aimed at protecting neurons, preserving myelin function and reducing the metabolic stress caused by myelin damage.

The study, published in the peer-reviewed Proceedings of the National Academy of Sciences (PNAS), found that myelin in the brain’s cortical gray matter does not primarily serve to speed nerve signals. Instead, its main function is to reduce the energy required for communication between neurons while maintaining stable brain activity.

The research was conducted by PhD student Oron Kotler under the supervision of Prof. Ilya Fleidervish from BGU’s Department of Physiology and Cell Biology, in collaboration with researchers from Soroka University Medical Center, the Weizmann Institute of Science and New York Medical College.

Myelin is a fatty insulating sheath that surrounds nerve fibers, known as axons, helping electrical signals travel efficiently through the nervous system. In peripheral nerves, myelin dramatically increases signal speed while reducing energy consumption. Its role in the brain’s gray matter, however—where densely packed neurons form complex networks—has remained less well understood.

Myelin beyond speed

Using advanced imaging, electrophysiological recordings and computer modeling, the researchers compared thin nerve fibers in the brain’s cortex with and without myelin. They found that myelination had little effect on signal speed: Both myelinated and unmyelinated cortical axons transmitted electrical impulses at nearly identical speeds of about 0.32 meters (1 foot) per second.

The key difference was energy consumption. Myelinated axons allowed 50% less sodium to enter during electrical signaling. Because neurons expend cellular energy in the form of adenosine triphosphate (ATP) to pump sodium back out and restore their chemical balance, the reduction effectively cuts the energy cost of transmitting signals in half.

The researchers found that cortical myelin is structurally distinct from myelin in peripheral nerves. Rather than forming long, tightly sealed insulating segments that maximize signal speed, cortical myelin consists of shorter insulated sections with more flexible junctions. This architecture enables neurons to conserve energy while maintaining normal electrical function.

The findings may also inform new approaches to drug development by identifying energy regulation as a key therapeutic target. Future treatments could focus on preserving myelin, protecting axons and helping neurons maintain their chemical balance after injury.

The findings may also offer insights for researchers developing energy-efficient artificial intelligence and brain-inspired computing systems.

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