手机版
for National Geographic News
Published October 3, 2011
Millions of receptors in the nose's smelling organ aren't scattered at random, a new study says. Instead, the receptors congregate in tiny hot spots that help the brain discern good smells from bad ones, among other potential functions.
一项新的研究表明，鼻腔内数以百万计的嗅觉受体并不是随机分布的。而是聚集在一些微小的区域里，它们可以帮助大脑辨别气味的好坏，同时还具备其他一些潜在的功能。
The evidence was gathered by sticking electronic probes up people's noses and measuring the chatter of nasal neurons as subjects were exposed to scents.
实验证据的收集是依靠一些电子探针。研究人员将电子探针插入受试者鼻腔内，测量受试者在嗅闻各种气味时嗅觉神经元所产生的信号变化。
The findings imply that the pleasantness of a smell is hardwired within our heads, calling into question the impact of life experience on how people perceive smells.
研究结果表明，辨别气味好坏的神经通路先天就隐藏在人类的大脑里。问题就是后天经验是如何对人类嗅觉产生影响的。
"It's both exciting and disturbing," said Don Wilson of the New York University School of Medicine, a neurobiologist who was not involved in the work."It doesn't fit in with what I think or a lot of other researchers think about smell."
“此事既让人感到兴奋又让人感到疑惑。”从事该项研究工作的纽约大学医学院神经生物学家Don Wilson说，“这样的结果与包括我在内的许多专家们对嗅觉的认识相抵触。”
Instead of the brain processing all scent information, for instance, it seems nasal neurons preprocess some of it—almost as if the nose has its own small brain.
譬如在处理嗅觉信息时，并不是所有的工作都由大脑来承担。鼻神经元似乎也承担了部分工作——鼻腔好象自己有自己的小脑一样。
◆Taking One in the Nose专一的嗅觉感知能力
The human nose contains a postage stamp-size smelling organ, called the olfactory epithelium, at the roof of the nasal cavity.
人类鼻腔的屋顶，有一块面积如邮票大小被称之为“嗅上皮”的嗅觉器官。
By probing mouse noses to measure the firing of nasal neurons, scientists had previously discovered that scent receptors might be organized into groups, similar to the way the tongue has zones armed to detect specific tastes such as sour, sweet, and salty.
科学家们通过对以往大鼠鼻腔神经元活动所做的测定实验发现，嗅觉受体有可能存在着嗅觉功能上的分工。其分工方式如同舌部，酸、甜、咸各种味道均有各自的感知区域。
But a rodent's nose has more than 1,200 different types of scent receptors, and even a tiny probe could touch tens of thousands of receptors in one reading, making it hard to get a clear signal.
然而，大鼠鼻腔内有1200多种嗅觉受体。探测器的顶端尽管比针尖还要细，但每次测到的是数以万计受体神经活动的信息，单个的信号无法辨别。
Humans have roughly 400 different kinds of receptors, however, making the business of sticking probes in noses and plucking out useful information more fruitful.
然而，人类鼻腔内约有400多种不同的嗅觉受体，能更有效地执行探测与识别有用信息的任务。
◆How the Nose Knows气味是如何分辨的
A team led by neuroscientist Noam Sobel, of the Weizmann Institute of Science in Israel, asked more than 80 people to sniff substances with odors known to be either pleasant or unpleasant across many cultures.
由以色列魏茨曼科学研究所神经学家Noam Sobel领衔的研究小组，要求80余名具有不同文化背景的被试识别各种已知气味的好坏。
Ordinary smells can be made up of tens to hundreds of compounds, so Sobel and his colleagues puffed only pure chemicals into the noses of their wired subjects, one scent at a time.
普通气味是由数十或数百种物质所构成的，因此，Sobel和他的同事每次向联有探测针的受试者的鼻腔内喷入的是纯净物，每次只感知一种气味。
Pooling together 801 neural recordings from people's noses, the team found that some regions of the epithelium are better at detecting scent than other regions. The researchers also found hot spots that are better at interpreting either pleasantness or unpleasantness.
从对人体鼻腔收集到的801项神经活动记录来看，小组人员发现某些区域的嗅上皮细胞比其它区域的对某种气味更具感知能力。研究人员还发现能更好地识别气味好坏的特定区域。
"To my surprise, this means something about the epithelium is tuned to pick up certain information" in certain zones, New York University's Wilson said."We don't understand what the purposes of those zones are," he added, "but that's exciting."
纽约大学的Wilson说，“真没想到，嗅觉上皮是一种检测特定嗅觉信息的结构。虽然这些区域的详细功能还未查明，但这一结果是值得令人兴奋的了。”
The smelling study was published online last week in the journal Nature Neuroscience.
有关研究成果发布于上周网络版的《自然神经科学》杂志。
相关阅读：科学家质疑「味觉分布图」
原文链接：Secrets of Smell: Different Nose Parts for Stinky, Sweet
