Challenges To Vibration Theory
Three predictions by Luca Turin on the nature of smell, using concepts of vibration theory, were addressed by experimental tests published in Nature Neuroscience in 2004 by Vosshall and Keller. The study failed to support the prediction that isotopes should smell different, with untrained human subjects unable to distinguish acetophenone from its deuterated counterpart. (However another study did find that subjects could distinguish deuterated benzaldehydes from regular benzaldehydes. See Isotope effects above.) In addition, Turin's description of the odor of long-chain aldehydes as alternately (1) dominantly waxy and faintly citrus and (2) dominantly citrus and faintly waxy was not supported by tests on untrained subjects, despite anecdotal support from fragrance industry professionals who work regularly with these materials. Vosshall and Keller also presented a mixture of guaiacol and benzaldehyde to subjects, to test Turin's theory that the mixture should smell of vanillin. Vosshall and Keller's data did not support Turin's prediction. However, Vosshall says these tests do not disprove the vibration theory.
In response to the 2011 PNAS study on flies, Vosshall acknowledged that flies could smell isotopes but called the conclusion that smell was based on vibrations an "overinterpretation" and expressed skepticism about using flies to test a mechanism originally ascribed to human receptors. For the theory to be confirmed, Vosshall stated there must be further studies on mammalian receptors. Bill Hansson, an insect olfaction specialist, raised the question of whether deuterium could affect hydrogen bonds between the odorant and receptor.
Read more about this topic: Vibration Theory Of Olfaction
Famous quotes containing the words challenges, vibration and/or theory:
“The approval of the public is to be avoided like the plague. It is absolutely essential to keep the public from entering if one wishes to avoid confusion. I must add that the public must be kept panting in expectation at the gate by a system of challenges and provocations.”
—André Breton (1896–1966)
“In the very midst of the crowd about this wreck, there were men with carts busily collecting the seaweed which the storm had cast up, and conveying it beyond the reach of the tide, though they were often obliged to separate fragments of clothing from it, and they might at any moment have found a human body under it. Drown who might, they did not forget that this weed was a valuable manure. This shipwreck had not produced a visible vibration in the fabric of society.”
—Henry David Thoreau (1817–1862)
“A theory if you hold it hard enough
And long enough gets rated as a creed....”
—Robert Frost (1874–1963)