Student volunteers presented with odors to one nostril or the other could reliably discern where the odor was coming from, and functional magnetic resonance images of their brains showed that the brain is set up to pay attention to the difference between what the left and right nostrils sense, much the way it can localize sounds by contrasting input from the ears.
"It has been very controversial whether humans can do egocentric localization, that is, keep their head motionless and say where the spatial source of an odor is," said study coauthor Noam Sobel, associate professor of psychology at UC Berkeley and a member of the campus's Helen Wills Neuroscience Institute. "It seems that we have this ability and that, with practice, you could become really good at it."
In future experiments, UC Berkeley biophysics graduate student Jess Porter and Sobel plan to train volunteers to track odors in the field and test the limits of odor localization in humans.
Porter, Sobel and their colleagues reported the results in the August 18 issue of the journal Neuron.
In a review appearing in the same issue of the journal, Jay A. Gottfried of the Department of Neurology at Northwestern University's Feinberg School of Medicine noted that the UC Berkeley findings open numerous avenues for further research. "Finally, what are the implications for the Provencal truffle hunt?" he wrote, only partly tongue-in-cheek. "In the traditional world of the truffle forests, the dog (or pig) is king. The evidence presented here suggests that humans are every bit as well equipped to carry out the search."
Forty years ago, Nobel Prize laureate Georg von Bekesy claimed that humans had the ability to localize odors, based on experiments in 1964 with human
Source:University of California - Berkeley