The Science of Smell

22 april 2020
How People Fought Diseases in the Past: a Top 10 of the Most Potent Smells

7 April 2020
「The Times of Israel」
Amid confusion over virus symptoms, Israeli scientist creates a sniff test tool
以色列科学家发现新冠肺炎患者会出现嗅觉丧失的症状，Noam Sobel，一位神经生物学系教授建立网站帮助人们评估嗅觉能力，全世界平均每小时约200人注册，注册者需要选择愿意每天闻的五种食料，包括蜂蜜、花生酱、醋、新切的大蒜和牙膏，人们会被提示每天嗅这些食料，然后调整滑块评估强度和愉悦度，如果气味感觉变化剧烈，网站会以红屏显示其嗅觉出了问题。
Sobel说他们的团队已经研发出重6克的可穿戴传感器检测鼻腔气流，通过蓝牙传输数据。

02nd February 2020
「The new indian express」
The research, which was led by author Giada Brianza from the University of Sussex, UK, claims that the smell or fragrance can influence the images we have in our mind related to our body. 
气味或者香气可能从影响我们脑海里的画面感继而影响到我们的身体。
The human sense of smell is so strong that it is often used to treat other ailments in the body. “For mental, physical and spiritual purposes, our ancestors have been using aroma therapy to heal related ailments and disorders. So for us smell and its related impact on our body and emotions are not new. These researches can only strengthen these old therapies,” highlights Dr Jaitly.
人类的嗅觉因为其重要性常被用于身体疗愈，我们祖先就以芳香疗法治疗或调理心理的身体的精神的疾病。所以，对我们而言，嗅觉影响我们的身心健康并不新鲜，这些研究者在印证古老治疗的价值。

10.24.2019
「Wired」
Google researchers are training neural networks with a new technique to predict how a molecule smells based on its chemical structure.
The science of smell lags behind many other fields. Light, for example, has been understood for centuries. In the 17th century, Isaac Newton used prisms to divide the white light of the sun into our now familiar red, orange, yellow, green, blue, indigo, and violet rainbow. Subsequent research revealed that what we perceive as different colors are actually different wavelengths. Glance at a color wheel and you get a simple representation of how those wavelengths compare, the longer reds and yellows transitioning into the shorter blues and purples. But smell has no such guide.
嗅觉的科学落后于许多其它领域。比如光，早在17世纪，牛顿用棱镜把太阳光谱分成我们今天熟悉的红橙黄绿青蓝紫7种颜色，之后的研究表明我们感知到的不同颜色其实是不同的波长。通过色轮你大致可以了解波长对比，红色最长，然后是黄色，再过渡到较短的蓝和紫。可是嗅觉却不是这样。
If wavelengths are the basic components of light, molecules are the building blocks of scents. When they get into our noses, those molecules interact with receptors that send signals to a small part of our brains called the olfactory bulb. Suddenly we think “mmm, popcorn!” Scientists can look at a wavelength and know what color it will look like, but they can’t do the same for molecules and smell.
如果波长是光的基本组成，分子则是气味的组成模块。当分子进入鼻腔，它们通过受体将讯号传入大脑中被称作嗅球的一小块区域，突然我们就反应过来，“嗯，爆米花。”科学家们通过波长知道颜色，但是通过气味分子则很难做出气味是什么的判断。

July 25, 2019
「Newsday」
Researchers at Cold Spring Harbor Laboratory, in a groundbreaking hunt to map the origins of humans' sense of smell, have found that olfaction relies on multiple regions of the brain — many undiscovered — and is far more complex than previously thought.
嗅觉依赖于大脑多个区域作用，许多尚不可知，其复杂性远超我们想象。
“We are in the 21st century and we still don’t really understand the sense of smell,” said Dr. Florin Albeanu, whose research paper, published this week in the journal Nature Neuroscience, challenges prevailing wisdom and poses new questions.
今天我们其实并不理解嗅觉。
“Olfactory experience is very subjective,”said Alexei Koulakov, also a neuroscientist at Cold Spring Harbor Lab. 
嗅觉体验非常主观。
“The perception of smells actually depends on the context and on an individual’s prior experience," Koulakov said.
嗅觉依赖于感知环境和个人经历。

May 3, 2019
「The New York Times」
You Will Never Smell My World the Way I Do
“We’re all smelling things a little bit differently,” said Steven Munger, director of The Center for Smell and Taste at the University of Florida.
每个人的嗅觉不太一样。
“Olfaction is the most important sense for the rest of the animal kingdom,” said Dr. Lomvardas. And though its essential role is less obvious when humans don’t have to sniff out their next meal, it still affects much more than just perfume preference and flavor experience. There is evidence that reduced sense of smell has psychological consequences, he said, and it may offer early clues of an oncoming neurodegenerative disorder such as Alzheimer's disease.
动物王国里嗅觉是最重要的感官。虽然人类不必要通过嗅觉觅食，看起来嗅觉似乎没那么重要，有证据表明嗅觉的缺失导致心理疾病，并可能预知一些神经退行性疾病，例如阿兹海默症。
Of course, genes are not the only determinant of scent. Rachel Herz, who studies the psychological science of smell at Brown University, calls this new study “great and important” but points out that there are many other factors at play, including attention, past associations and expectations.
基因不是嗅觉的唯一决定因素。还有更多其它因素起作用，包括注意力、过去的经历和心理预期。
“There’s also an ability to create odor illusions and flip people’s perception of an odor,” she said. She’s done this by presenting people with a chemical combination and telling them that it’s vomit. She then presented the same chemical combination and told them it was Parmesan cheese. The participants refused to believe that the samples were the same, she said, as one was so clearly disgusting and the other was so clearly delicious.
我们可以制造气味幻觉改变人们的看法。她曾把一种化学合成物给人们看，告诉他们这是呕吐物，而后以同样的化学物质告诉大家这是帕尔马干酪，但没有人相信这是一个东西，因为前者看起来恶心，后者则很诱人。

May. 11, 2017
「Science」
Your nose knows more than scientists thought
Poor human olfaction is a 19th-century myth
You’ve probably heard that your sense of smell isn’t that great. After all, compared with a dog or even a mouse, the human olfactory system doesn’t take up that much space. And when was the last time you went sniffing the ground alongside your canine companion? But now, in a new review published today in Science, neuroscientist John McGann of Rutgers University in New Brunswick, New Jersey, argues that the myth of the nonessential nose is a huge mistake—one that has led scientists to neglect research in a critical and mysterious part of our minds. 
你们也许听说过我们人类的嗅觉不够敏感，和狗、老鼠比，人的嗅觉系统占比不够大。你最后一次循着味道逗家里的狗狗是什么时候？今天出版的《科学》杂志，神经科学家认为，所谓鼻子不重要的观点完全错误——这个错误使科学家们忽视了对我们意识里这一关键又神秘部分的探究工作。
Every sense is unique and has its own quirks, bugs, and features in the human brain. One of the things that makes smell distinctive is that olfactory information is not rooted through this “switchboard” structure called the thalamus on the way to other “thinking” brain regions. It goes from the nose to the olfactory bulb and then directly from there to the olfactory [processing area] but also to places like the amygdala and the hippocampal formation, which are involved in emotion and memory. It’s a very common experience to have smells evoke strong memories. It's been speculated that that might be related to the different wiring.
每一种感觉都是独特的，在我们的大脑里有自己的癖好、不足和特点。嗅觉之所以更特别是因为气味信息不通过丘脑（中枢结构）抵达大脑的思维区域，而是从鼻腔到嗅球然后直接通过嗅觉信号处理区域抵达杏仁核和海马体，激发情感和记忆。嗅觉引发强烈的记忆司空见惯，大概与嗅觉信号处理机制不同有关。
Another [factor] is that the nature of smell is very synthetic. Most smells in the real world are mixtures of lots of chemicals. A cup of coffee has about 150 different chemicals … that you can smell. But you don't have 150 dimensional perceptions—you just smell coffee. You can't really think of it or label it quite as easily as you can describe the [sight of the] cup that the coffee is in or the music that's playing in the background.
嗅觉的另一个特点是它的合成性。现实世界里我们闻到的是大量化学物的混合。我们可以在一杯咖啡里嗅到大约150种不同的化学成份……不过我们却不需要150种感知维度。相较于描述咖啡杯或是背景音乐描述和确认咖啡本身则要困难得多。

Jan. 2015 Asifa Majid awarded Ammodo KNAW Award 2015 for Humanities

Innovative fieldwork carried out by Majid has undermined such dogmas. She discovered that small nomadic people in the rainforests of Thailand and Malaysia certainly appear to have a large abstract smell vocabulary, which they apply just as consistently as their colour vocabulary. Perhaps human beings do have the potential to develop a rich scent language, but that potential is not used where odour is less important for survival and, unlike in the rainforest, it is not necessary to pass on such language to children. 

In addition to fieldwork, Majid is also actively engaged in lab work. ‘I’m very enthusiastic about a new study among wine and coffee experts. I’d really like to determine what makes someone an expert. And whether this is reflected in their language use pertaining to taste and smell.’ She would also like to conduct research into perfume experts. ‘Unfortunately, they are few and far between.’