Scientists Map 539 Hidden Chemical Zones in the Mouse Brain

Keypoints:

• Researchers at École Polytechnique Fédérale de Lausanne (EPFL) built a 3D map of lipids across the mouse brain
• The map reveals 539 chemically distinct zones called lipizones
• The team analyzed 172 lipids across 109 brain slices
• About seven million measurements were combined with machine learning
• The Lipid Brain Atlas is freely available online

Lipids are the fatty molecules that give the brain its structure and help cells communicate. Researchers at EPFL have now mapped them in three dimensions. Their work covered a whole mouse brain. The result is a chemical atlas with 539 distinct zones, which the team named lipizones.

The method is mass spectrometry imaging. It measures which lipids sit at each spot in a thin tissue slice. The team analyzed 172 lipids across 109 slices and gathered about seven million measurements. Machine learning then grouped spots with matching chemical signatures into zones.

Some lipizones line up with familiar anatomical structures. Others reveal boundaries that traditional maps miss. The atlas also shows links between distant brain areas that share similar lipid chemistry.

White matter holds a surprise. It was once seen as relatively uniform. The new map shows a complex patchwork of chemically distinct regions inside it. That suggests the brain's wiring is organized at a chemical level too.

The atlas is open to scientists worldwide through the Lipid Brain Atlas. Researchers can compare lipid zones with anatomy and cell types. They can also look for chemical changes linked to development, aging or disease.

The authors are careful about limits. The mouse map cannot be placed directly onto a human brain. The transferable achievement is the method. The same approach applied to human tissue could show whether similar organizing principles exist.