Scientists at the Indian Institute of Technology Madras (IIT M) have constructed a three-dimensional atlas of the human brainstem, detailing more than 200 structures at the resolution of individual cells. Experts believe this achievement could revolutionize how doctors diagnose and treat neurological diseases.
What is the brainstem and why does it matter?
The brainstem is a stalk-like structure connecting the brain to the spinal cord. It controls essential functions such as breathing, sleep, wakefulness, and movement. Damage to the brainstem underlies some of the most severe neurological conditions. Previously, doctors relied on maps that were too vague to identify precisely which cells were affected.
Introducing ANCHOR: A 'Google Earth' for the brainstem
The new atlas, named ANCHOR, changes that, IIT M announced on Friday. It functions like a 'Google Earth' of the brainstem. A doctor can begin with an MRI scan, then zoom down through tissues, through fibre tracts that act like internet cables carrying signals between brain regions, all the way to a single cell. To distinguish cell types, researchers applied eight chemical dyes, called immunostains, across several hundred tissue slices, lighting up specific proteins in each cell.
Key features and availability
The atlas spans brains from the prenatal period through adulthood and is available free at anchor.humanbrain.in. 'These maps will help identify specific cell populations affected in brainstem lesions, which could be critical for clinical applications,' said Ajay Kumar Sood, principal scientific adviser to the government of India. ANCHOR was unveiled at the 3rd BRICS Neuroscience Symposium at IIT M conducted from June 5 to 7. The institute collaborated with CMC Vellore, Govt Kilpauk Medical College, Sri Ramachandra Institute of Higher Education and Research, and MediScan Systems.
Part of a larger mission
The atlas is the latest advance from the Sudha Gopalakrishnan Brain Centre at IIT Madras, which in December 2024 released DHARANI — a detailed atlas of the human fetal brain that became a large publicly accessible digital dataset. Researchers froze five fetal brains from pregnancies that did not go to term, sliced them into slivers one-tenth the width of a human hair and spent nearly a year digitally stitching each brain back together. When imported equipment ran short during the Covid-19 lockdown, the team built the technology themselves. The centre is also mapping brains affected by rabies, dementia and Alzheimer's disease.
Future implications
ANCHOR is the centre's next leap: from the fetal brain to the adult brainstem, and from anatomy to the chemistry of individual cells. 'We envision that these maps and atlases will have significant implications for neuroscience and neuromedicine,' said professor Mohanasankar Sivaprakasam, who heads the centre. 'We have a mission to image more than 100 whole brains across the human lifespan, from womb to tomb, and of various neurological diseases.' The centre draws on more than 200 researchers and 20 international collaborators.
Quick facts about ANCHOR
- What is it: A detailed, free, three-dimensional map of the human brainstem
- What makes it different: Doctors and researchers can zoom from a hospital MRI scan all the way down to a single brain cell
- What does it cover: 200+ brainstem structures, including pathways that carry signals between brain regions, across fetal, childhood and adult brains
- Who can use it: Anyone — researchers, doctors and scientists worldwide. anchor.humanbrain.in is open access
- What diseases could it help: Stroke, tumours, Alzheimer's, dementia and rabies — any condition that damages the brainstem.
