A High-Resolution 3D Atlas Uncovers Hidden Brain Geography

The mammalian brain is an intricate web of neurons, yet a complete blueprint of how these cells are arranged in three-dimensional space has long been missing. Previous studies often lacked the scope to map molecularly defined neurons across the entire organ simultaneously. In a significant step forward, researchers have now utilised transgenic mice and fMOST imaging to chart the spatial distribution of neurons at the single-cell level throughout the whole brain.

The team focused on mapping glutamatergic, GABAergic, and modulatory neurons—the primary signalling units of the brain. By registering individual cells to a standardised coordinate framework, they constructed a detailed cellular atlas. This systematic approach allowed for the precise observation of how these different cell types are organised in 3D space.

The analysis uncovered remarkable diversity in cellular composition. While some patterns matched the boundaries of known brain regions, the study revealed previously uncharacterised subdivisions in others. Notably, cortical and subcortical nuclei as small as one millimetre displayed complex internal structures. These findings suggest the presence of finer functional zones, providing a much clearer window into the brain's sophisticated organisation.