2012年11月21日 訊 /生物谷BIOON/ --近日,，來自以色列魏茨曼科學研究所的研究人員通過研究發(fā)現(xiàn)，世間存在一種通用氣味,，名為“嗅覺白”,，其類似于“白顏色”（color white）和“白噪音”（white noise）,，研究者將其命名為“Laurax”并對其進行深入研究，相關研究成果刊登于國際雜志PNAS上,。
許多人都知道白噪音和白顏色,，因為其都由于許多成分的混合而產生。當多個音調同時進行播放的時候,，人們就會聽到“白噪音”,，類似地，當多種波長匯集的時候,，就會產生白顏色,，研究者想知道，是否氣味也有類似的現(xiàn)象發(fā)生,。
首先,，研究者對86種包括所有嗅覺譜的氣味進行混合，隨后取了少量的樣品,，然后將它們進行混合制成許多種氣味樣品,，并且使得單一氣味從1變化到43，隨后將這些樣品暴露于59名參與者中,，對其進行調查分析,。
研究結果顯示，隨著每種樣品氣味數(shù)量的增加,，參與者區(qū)分/分辨出這些氣味的難度越大,，當氣味數(shù)量達到30的時候，研究者發(fā)現(xiàn),，大多數(shù)的人根本不可能區(qū)分出來,，當氣味達到一定水平的時候，就會變成一種獨特的氣味,，研究者將其命名為“Laurax”,。
為了進行深入研究，研究者進行了另外一項實驗,，讓參與者在3天時間里對Laurax中的四個樣品進行嗅覺測試,，并且熟悉這些氣味。在第四天的時候,，參與者被要求嗅出四種氣味混合物,，并且分別貼上標簽，研究者發(fā)現(xiàn),，當Laurax含有大量氣味的時候,，參與者更易于對其有深刻印象，尤其是當氣味數(shù)量達到30的時候。與此同時研究者也發(fā)現(xiàn),，大部分的志愿者可以區(qū)分出Laurax中不同的混合氣味成分,，這就類似于區(qū)分深淺不一的不同白顏色一樣。（生物谷Bioon.com）
編譯自：Researchers discover generic 'white' odor Laurax
doi:10.1073/pnas.1208110109
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PMID:
Perceptual convergence of multi-component mixtures in olfaction implies an olfactory white
Tali Weissa,1,2, Kobi Snitza,1, Adi Yablonkaa, Rehan M. Khana, Danyel Gafsoub, Elad Schneidmana, and Noam Sobela,2
In vision, two mixtures, each containing an independent set of many different wavelengths, may produce a common color percept termed “white.” In audition, two mixtures, each containing an independent set of many different frequencies, may produce a common perceptual hum termed “white noise.” Visual and auditory whites emerge upon two conditions: when the mixture components span stimulus space, and when they are of equal intensity. We hypothesized that if we apply these same conditions to odorant mixtures, “whiteness” may emerge in olfaction as well. We selected 86 molecules that span olfactory stimulus space and individually diluted them to a point of about equal intensity. We then prepared various odorant mixtures, each containing various numbers of molecular components, and asked human participants to rate the perceptual similarity of such mixture pairs. We found that as we increased the number of nonoverlapping, equal-intensity components in odorant mixtures, the mixtures became more similar to each other, despite not having a single component in common. With ∼30 components, most mixtures smelled alike. After participants were acquainted with a novel, arbitrarily named mixture of ∼30 equal-intensity components, they later applied this name more readily to other novel mixtures of ∼30 equal-intensity components spanning stimulus space, but not to mixtures containing fewer components or to mixtures that did not span stimulus space. We conclude that a common olfactory percept, “olfactory white,” is associated with mixtures of ∼30 or more equal-intensity components that span stimulus space, implying that olfactory representations are of features of molecules rather than of molecular identity.
