From gene maps to fat maps
Researchers at EPFL in Switzerland have built the first three-dimensional atlas of the brain based on fats rather than genes. The work, published in the journal Nature, maps the mouse brain by its lipid chemistry.
Earlier brain atlases sorted tissue by which genes were switched on in each cell. The new approach instead tracks where different fat molecules sit, using imaging that reads chemical signatures straight from thin slices of tissue.
Lipids act as molecular postcodes
The map revealed 539 chemically distinct regions, which the team calls lipizones. Some line up with structures scientists already knew about. Others mark chemical boundaries that no gene-based map had shown.
The researchers also found that regions far apart in the brain but linked by nerve fibres often share similar lipid patterns, suggesting fats help define how distant circuits are built and maintained. White matter, long treated as fairly uniform, turned out to be a patchwork of separate lipid zones, with the cortex showing wide variation across its layers.
Clues for Alzheimer's research
Lipids make up a large share of the brain's dry weight and are central to how nerve cells signal. Changes in fat metabolism have been linked to Alzheimer's disease, depression and other conditions, but it has been hard to say where in the brain those changes start.
A reference map gives researchers a way to compare healthy tissue with diseased tissue at fine scale, and to ask whether lipid shifts help cause disease or follow from it. The team has released the atlas for other laboratories to use, and plans to extend the method to other tissues and to human samples.