New Delhi: Scientists have created a detailed map of the brain's hidden chemical landscape, identifying 539 distinct regions based on the distribution of fats that help nerve cells function. The discovery could offer new ways to understand how the brain works and how conditions such as Alzheimer's disease and depression affect it.
Researchers at Switzerland's EPFL University developed the Lipid Brain Atlas, a three-dimensional map showing how different fats, known as lipids, are distributed across the mouse brain. The findings were published in the journal Nature.
While scientists have extensively studied brain cells, genes and proteins, lipids have received comparatively less attention. These fatty molecules form the protective membranes around cells, help insulate nerve fibres and play important roles in communication between brain cells. Until now, scientists have struggled to determine precisely where different types of lipids are located in the brain.
To build the atlas, the research team examined 109 brain slices collected from 11 mice, analysing 172 different lipids. Using an imaging technique that identifies chemicals in tissue, the researchers generated approximately seven million measurements and combined them using machine-learning tools. The resulting map revealed 539 chemically distinct regions, which the researchers named lipizones.
Some corresponded to familiar brain structures, while others revealed previously unknown chemical boundaries. Researchers also found that distant brain regions connected by nerve fibres could share similar lipid patterns. The team compared these patterns to postal codes, suggesting that lipids could help identify relationships between brain regions that are difficult to detect through anatomy or genetic information alone.
The findings also challenged existing assumptions about white matter, the tissue containing nerve fibres that connect different parts of the brain. Rather than having a relatively uniform chemical composition, white matter contained numerous distinct lipid zones.
The researchers also examined how pregnancy affects the brain's chemical composition in mice. They found widespread changes in lipid levels across several brain regions, with the overall differences more pronounced than typical differences between male and female mice.
The brain's outer layer, known as the cortex, showed particularly extensive changes. Levels of galactosyl ceramide, a lipid important for the insulating layer around nerve fibres, also increased sharply across much of the white matter.
The findings suggest that pregnancy is accompanied by substantial changes in the brain's chemical makeup, although further research is needed to establish what these changes mean for brain function.
The Lipid Brain Atlas is freely available online, providing scientists with a reference map of the healthy mouse brain. Researchers could use it to investigate how changes in lipid distribution relate to brain development, ageing and neurological conditions, including Alzheimer's disease and depression.
The map cannot be directly applied to humans, but the method could eventually help scientists build similar maps of the human brain, offering a more complete picture of its organisation and chemistry.