Scientists at the Indian Institute of Technology Madras have produced the world’s most detailed three-dimensional atlas of the human brainstem at cellular resolution, a digital map called ANCHOR that lets researchers travel seamlessly from MRI scans of the whole brain to individual nerve cells. Built from more than 500 tissue sections spanning fetal, childhood, and adult brains, the atlas identifies over 200 clusters of brain cells and nerve pathways. The freely available resource could transform understanding of neurological disorders from Parkinson’s and Alzheimer’s to stroke and sudden infant death syndrome. The team spent 18 months manually analyzing over 200 brain sections, and now plans to image more than 100 whole human brains to create a reference library of how disease reshapes the brain cell-by-cell.