Lipid Landscape of the Mouse Brain Mapped

The brain is usually described through its cells and circuitry, but much of its physical structure is built from lipids—the fats that form neuron membranes, wrap nerve fibers in myelin, and support how brain cells communicate. Despite that role, lipids have remained difficult to study: unlike genes and proteins, which have been charted extensively, standard imaging tools have struggled to tell individual lipid molecules apart.

“So scientists have had only a blurry picture of how lipids differ from one part of the brain to another,” says Giovanni D’Angelo, senior author of a new study published in Nature. “That gap matters, because changes in brain lipids are increasingly linked to conditions from depression to Alzheimer’s disease.”

A team led by D’Angelo, Luca Fusar Bassini, and Gioele La Manno at EPFL has now built a detailed lipid atlas covering the entire mouse brain. The Lipid Brain Atlas shows that lipids are arranged in a precise, orderly pattern that matches known brain anatomy and also reveals boundaries anatomy alone hasn’t captured—the pattern was distinctive enough that the team could identify where in the brain a tissue sample came from using lipid data alone.

To build the atlas, the researchers used mass spectrometry imaging, a technique that fires a laser point-by-point across thin brain slices and records the lipids present at each spot. In total, they measured 172 lipids across 109 slices taken from 11 mice, then used custom machine-learning tools to turn roughly 7 million individual readings into a single 3D model of the whole brain. The resulting map split the brain into 539 distinct regions, called “lipizones,” each defined by its own combination of lipids. 

Many lipizones align with familiar cell types and brain regions, but others connect clusters of nerve cell bodies to the distant areas their fibers extend into—links that maps built from gene data have typically missed. “In effect, lipids work like postal codes, giving distant but related parts of the brain the same chemical address,” D’Angelo says. The atlas also found that white matter, long assumed to be largely uniform, is actually divided into distinct chemical zones, along with further boundaries in the choroid plexus and the linings of the brain’s internal cavities.

The atlas additionally tracked how brain lipids shift during pregnancy, finding changes across many regions that were larger than typical differences between males and females. The cortex was substantially reshaped, and galactosyl ceramide, a core component of myelin, increased sharply through much of the white matter. “Together, these shifts suggest the brain retunes its own wiring to meet the demands of pregnancy,” says La Manno.

The Lipid Brain Atlas is freely available online, giving researchers a new reference point for studying where lipids go wrong in development, aging, and disease. As Fusar Bassini put it, “What transfers to humans isn’t the map, it’s the method, and the fact that we now know that a healthy brain has a very organized lipid map at all.”