Researchers at Harvard Medical School have uncovered a hidden map of smell receptors in mice noses, revealing neat stripes instead of random distribution. This structure aligns with brain mapping, challenging prior assumptions about olfaction. The findings, published April 28 in Cell, could aid treatments for smell loss.
Scientists led by Sandeep (Robert) Datta, a professor of neurobiology at Harvard Medical School's Blavatnik Institute, analyzed 5.5 million neurons from over 300 mice. Using single-cell sequencing and spatial transcriptomics, they found that olfactory neurons form horizontal bands or stripes grouped by receptor type, running from the top to the bottom of the nose. This organization matches maps in the olfactory bulb of the brain, bringing order to what was thought to be a chaotic system. Datta said, 'Our results bring order to a system that was previously thought to lack order, which changes conceptually how we think this works.' The study appeared in Cell on April 28, 2026, with DOI: 10.1016/j.cell.2026.03.051. Additional authors include David Brann, Tatsuya Tsukahara, and others. A separate study by Catherine Dulac's lab at Harvard, published in the same issue, confirmed the findings. The team identified retinoic acid as key to forming this map, with its gradient guiding receptor activation. Altering levels shifted the entire map. Datta noted, 'We show that development can achieve this feat of organizing a thousand different smell receptors into an incredibly precise map that's consistent across animals.' Unlike vision or hearing, smell had lacked such a map despite decades of research since receptors were identified in 1991. Mice have over 20 million olfactory neurons and more than 1,000 receptor types, far more complex than human color vision's three. These insights could inform therapies for smell loss, which impacts safety, nutrition, and mental health. Datta emphasized, 'We cannot fix smell without understanding how it works on a basic level.' Funding came from the National Institutes of Health and others.
