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The brain knows what the nose smells, but how?

February 7, 2011
Stanford University
Biologists have developed a new technique to trace neural pathways across the brain. They have mapped the path of odor signals as they travel to the higher centers of a mouse brain, illuminating the ways mammalian brains process smells.

Credit: L.A. Cicero, Stanford University News Service








This first virus left the neurons susceptible to infection by the second virus, which was injected two weeks later. The second virus -- fluorescent red in color -- was designed by collaborator Edward Callaway at the Salk Institute.



They found that most of the nerve pathways heading to the higher processing centers that direct the mice's innate like or dislike of certain odors, and trigger a response to them, originated from one region -- the top part of the olfactory bulb. This could explain how the mouse brain directs the animal's innate fear response to cat or fox urine.





Story Source:

The above post is reprinted from materials provided by Stanford University. The original item was written by Sandeep Ravindran. Note: Content may be edited for style and length.

Journal Reference:

  1. Kazunari Miyamichi, Fernando Amat, Farshid Moussavi, Chen Wang, Ian Wickersham, Nicholas R. Wall, Hiroki Taniguchi, Bosiljka Tasic, Z. Josh Huang, Zhigang He, Edward M. Callaway, Mark A. Horowitz, Liqun Luo. Cortical representations of olfactory input by trans-synaptic tracing. Nature, 2010; DOI: 10.1038/nature09714

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Stanford University. "The brain knows what the nose smells, but how?." ScienceDaily. ScienceDaily, 7 February 2011. <>.
Stanford University. (2011, February 7). The brain knows what the nose smells, but how?. ScienceDaily. Retrieved August 27, 2016 from
Stanford University. "The brain knows what the nose smells, but how?." ScienceDaily. (accessed August 27, 2016).