A new study published in Cell titled, “A spatial code governs olfactory receptor choice and aligns sensory maps in the nose and brain,” led by researchers from Harvard Medical School (HMS) has created the first detailed map of the spatial distribution of over 1,000 olfactory receptors in the epithelium. The study informs the development of therapies for loss of smell, where treatment options are limited. The researchers examined approximately 5.5 million neurons in more than 300 individual mice using single-cell sequencing and spatial transcriptomics. Results showed that neurons are organized into tight, overlapping, horizontal stripes from the top to the bottom of the nose based on the type of smell receptor expressed. This highly organized receptor map was consistent across mouse models and mirrored the organization of smell maps in the brain. Similar maps have been observed in vision, hearing, and touch. Notably, the olfactory map was informed by a gradient of retinoic acid in the nose, which allowed each neuron to express the correct type of smell receptor based on its spatial location. “Our results bring order to a system that was previously thought to lack order, which changes conceptually how we think this works,” said Sandeep (Robert) Datta, PhD, professor of neurobiology at HMS and senior author and corresponding author of the study. “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.” The authors also found that the receptor map in the nose matches up with smell maps in the olfactory…
