2012年11月21日 讯 /生物谷BIOON/ --近日,来自以色列魏茨曼科学研究所的研究人员通过研究发现,世间存在一种通用气味,名为“嗅觉白”,其类似于“白颜色”(color white)和“白噪音”(white noise),研究者将其命名为“Laurax”并对其进行深入研究,相关研究成果刊登于国际杂志PNAS上。
许多人都知道白噪音和白颜色,因为其都由于许多成分的混合而产生。当多个音调同时进行播放的时候,人们就会听到“白噪音”,类似地,当多种波长汇集的时候,就会产生白颜色,研究者想知道,是否气味也有类似的现象发生。
首先,研究者对86种包括所有嗅觉谱的气味进行混合,随后取了少量的样品,然后将它们进行混合制成许多种气味样品,并且使得单一气味从1变化到43,随后将这些样品暴露于59名参与者中,对其进行调查分析。
研究结果显示,随着每种样品气味数量的增加,参与者区分/分辨出这些气味的难度越大,当气味数量达到30的时候,研究者发现,大多数的人根本不可能区分出来,当气味达到一定水平的时候,就会变成一种独特的气味,研究者将其命名为“Laurax”。
为了进行深入研究,研究者进行了另外一项实验,让参与者在3天时间里对Laurax中的四个样品进行嗅觉测试,并且熟悉这些气味。在第四天的时候,参与者被要求嗅出四种气味混合物,并且分别贴上标签,研究者发现,当Laurax含有大量气味的时候,参与者更易于对其有深刻印象,尤其是当气味数量达到30的时候。与此同时研究者也发现,大部分的志愿者可以区分出Laurax中不同的混合气味成分,这就类似于区分深浅不一的不同白颜色一样。(生物谷Bioon.com)
编译自:Researchers discover generic 'white' odor Laurax
doi:10.1073/pnas.1208110109
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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.