A new study explores how the brain encodes different scents — a topic which scientists know relatively little about, compared to our other senses.
- Unlike sight and hearing, our sense of smell remains poorly understood.
- In a new study, scientists used machine learning to categorize thousands of different odors based on chemical properties.
- By exposing mice to odors and measuring their neural activity, the scientists found that the brain more closely groups together odors that are chemically similar.
Illustration of multiphoton microscopy
Pashkovski et al.<p style="margin-left: 20px;"><br></p><p>To investigate, the researchers created a database of thousands of odorous chemical structures, and they used machine learning to categorize them by features such as number of atoms, molecular weight and electrochemical properties. These odors were separated into three categories: high diversity, intermediate diversity and low diversity.</p><p>Then the researchers exposed different odors to mice, and used multiphoton microscopy to record neural activity in the piriform cortex and olfactory bulb. The results showed that when odors are chemically similar, so too is neural activity. In other words, the cortex emphasizes relationships between chemically similar odors, and it creates groupings for similar odors, which helps us distinguish between objects in the world. </p>
Smell and neuroplasticity<p>The results also suggest that perception of smell is flexible. For example, the team repeatedly exposed mice to a combination of two chemically dissimilar odors. Over time, images showed that the neural patterns produced by the pair of odors become more strongly correlated.</p><p style="margin-left: 20px;">"We presented two odors as if they're from the same source and observed that the brain can rearrange itself to reflect passive olfactory experiences," Datta said. "The plasticity of the cortex may help explain why smell is on one hand invariant between individuals, and yet customizable depending on our unique experiences."</p>
Pixabay<p>The study provides some of the first information on how the olfactory cortex maps different odors. And the results also suggest that, by better understanding the chemical structure of different odors and how that mapping process works, scientists may someday be able to better control our sense of smell.</p><p style="margin-left: 20px;">"We don't fully understand how chemistries translate to perception yet," Datta said. "There's no computer algorithm or machine that will take a chemical structure and tell us what that chemical will smell like. To actually build that machine and to be able to someday create a controllable, virtual olfactory world for a person, we need to understand how the brain encodes information about smells. We hope our findings are a step down that path."</p>
Ever want to smell like an astronaut? Now you can!
- After years of trying, a group has produced the smell of outer space in a perfume.
- Astronauts have described the smell of space as similar to "ozone," "gunpowder," and "fried steak."
- Exactly what causes the scent is still debated.
In Space, nobody can figure out what that smell is.<div class="rm-shortcode" data-media_id="zAZNB0yY" data-player_id="FvQKszTI" data-rm-shortcode-id="90e83939c0919d5669cff58bf331cb90"> <div id="botr_zAZNB0yY_FvQKszTI_div" class="jwplayer-media" data-jwplayer-video-src="https://content.jwplatform.com/players/zAZNB0yY-FvQKszTI.js"> <img src="https://cdn.jwplayer.com/thumbs/zAZNB0yY-1920.jpg" class="jwplayer-media-preview" /> </div> <script src="https://content.jwplatform.com/players/zAZNB0yY-FvQKszTI.js"></script> </div> <p>NASA has been concerned about what space smells like for years, primarily to reduce the surprise to astronauts who go up for the first time. According to Eau de Space's Kickstarter video, the space agency has been using a reproduction of the smell of space for decades.</p><p>In 2008, they asked Steve Pearce, a chemist who founded <a href="https://www.omegaingredients.co.uk/" target="_blank">Omega Ingredients</a>, to help them create the <a href="https://www.cnn.com/2020/06/28/us/eau-de-space-fragrance-scn-trnd/index.html" target="_blank">smell for an exhibition</a>, presumably a more difficult task than giving new astronauts a spritz. Now, thanks to what they dub "sheer determination, grit, a lot of luck, and <em>a couple of</em> Freedom of Information Act (FOIA) requests," the team behind the Kickstarter hopes to bring the scent to the public. <br> <br> Descriptions of what it smells like are all over the place, and include raspberries, rum, "spent gunpowder," hot metal, fried steak, and "ozone."</p><p>For those wondering when you'd get a chance to notice the smell with a helmet on, as is required for spacewalks or moonwalks, the scent follows astronauts as they return from spacewalks. According to a researcher who spoke to <a href="https://www.theatlantic.com/technology/archive/2012/07/what-space-smells-like/259903/" target="_blank">The Atlantic</a>, the odor is created by "high-energy vibrations in particles brought back inside which mix with the air."</p><p>As to why it smells like the various things mentioned above, the jury is still out. One <a href="https://www.businessinsider.com/what-does-space-smell-like-2016-3" target="_blank">suggestion</a> is that at least some of the particles are hydrocarbons, which can also be found in things like tobacco smoke and car exhaust here on Earth. NASA argues that at least some of the smell is caused by oxidation of these particles, whatever they may be, as they enter the oxygen-rich <a href="https://science.nasa.gov/science-news/science-at-nasa/2006/30jan_smellofmoondust/" target="_blank">environment of the spacecraft</a>. </p><p>The plan is for the fragrance to be used primarily as an educational tool, sparking conversations about outer space in the classroom. To this end, each purchase includes a one bottle donation to a K-12 school. According to <a href="https://www.engadget.com/nasa-smell-of-space-perfume-kickstarter-145104834.html" target="_blank">Engadget</a>, there are currently no plans to mass-produce the fragrance after the Kickstarter ends.</p><p>If you want some, you might want to make that move before the countdown hits zero. </p>
Researchers decoded the love signals of lizards "spoken" through chemical signals.
- Scientists discovered that lizards developed novel chemical communication signals when relocated to tiny island groups with no predators.
- Male lizards began to rapidly produce a new chemical love elixir, not unlike cologne, to call on potential mates.
- With new technology we're increasingly able to detect and identify the chemicals that make up much of the language of non-human nature.
Discovery of lizard love language dialects<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzE2OTMzOC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY1MjA1MjcxMH0.WZUBceriGkgHhb5yza4468TF9aJDvmdJGqW7wVERHgU/img.jpg?width=1245&coordinates=0%2C89%2C0%2C90&height=700" id="0bda9" class="rm-shortcode" data-rm-shortcode-id="9c6e02aa7dfbb5e8f23aed152fd1e21b" data-rm-shortcode-name="rebelmouse-image" />
Agios Artemios was one of the islets that a lizard group was relocated to.
Photo Credit: Colin Donihue<p>Researchers from Washington University in St. Louis relocated 12 female and eight male Aegean wall lizards from a single source lizard population in Greece to five tiny islands with no predators. Under these happy conditions, the lizard population proliferated and competed aggressively—evidenced by bite scars—for resources. Researchers tagged each individual lizard so that they could be identified and checked up on over the course of four years.</p><p>As the scientists made visits back to the lizard populations to note how they and their offspring were doing, they made a exciting discovery. On each of the islands, the male lizards had made new chemical cocktails different from the chemical secretions of the lizards in the original source population. The changes had happened rapidly, becoming evident to the scientists after just four generations.</p><p>Could this be evidence that male lizards spruce themselves up with new, au naturale "cologne" when in new ecological settings? The researchers think so, pointing out that having no predators around likely made all the difference. </p><p>"Signals to attract mates are often conspicuous to predators," said Simon Baeckens, a postdoctoral fellow at the University of Antwerp in Belgium and co-author of the new paper, in a <a href="https://source.wustl.edu/2020/04/lizards-develop-new-love-language/" target="_blank">university news release</a>. "As such, sexual signals present a compromise between attractiveness and avoidance of detection. However, on these islets, there is no constraint on the evolution of highly conspicuous and attractive signals." </p><p>In other words, with no snakes or other predators to clue in on their prey's potent chemical secretions, the male lizards could let loose on their love signals without worry. </p><p>"In the experimental islands, we found that the 'signal richness' of the lizard secretions is the highest—meaning that the number of different compounds that we could detect in the secretion is the highest," <a href="https://source.wustl.edu/2020/04/lizards-develop-new-love-language/" target="_blank">Baeckens added</a>. </p><p>Though the researchers are still working to decode the signals, they note that previous research suggests that this more elaborate signal may advertise high "male quality" and possibly immune function to both lure females and tell other males to scram. </p><p>"Lizards deposit their chemical messages encoded in secretions from specialized glands located on their inner thighs," reported Talia Ogliore for <a href="https://source.wustl.edu/2020/04/lizards-develop-new-love-language/" target="_blank">Washington University</a>. "The secretions are a waxy cocktail of lipid compounds that contains detailed information about the individual lizard that produced them."</p><p>Lizards are able to collect those chemical messages from their environment by rapidly flickering out their slim, nimble tongues. They process those cues via a sensory organ in the roof of their mouths.</p>
Chemical dialects<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="71eb9f69f0ff048c645911b7b444da85"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/7kHZ0a_6TxY?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span><p>Most chemical signals between animals fall out of the parameter of human perception, and are therefore more complex to examine. So when studying animal communicative signals, studies have typically prioritized sound and sight.<br></p><p>But chemical "language" is the oldest and most widely used communication mode in nonhuman nature. Life spanning from bacteria to <a href="https://www.the-scientist.com/features/plant-talk-38209" target="_blank">plants</a> to <a href="https://link.springer.com/chapter/10.1007/978-1-4615-4733-4_23" target="_blank">beavers</a> all communicate through this medium. So research like this new paper on lizard love signals represents a valuable opportunity for deciphering ways that animals communicate and perceive the world around them. </p><p>"What we've discovered is that within species there is important variation in chemical signals depending on your context: Who's trying to eat you, who wants to mate with you and who you're trying to compete with," said <a href="https://biology.wustl.edu/people/colin-donihue?" target="_blank">Colin Donihue</a>, a postdoctoral fellow in biology in Arts & Sciences at Washington University in St. Louis and lead author of the new study.</p><p>Donihue also pointed out that nonhuman species have spent more than a billion years developing complex chemical languages. Only relatively recently have humans been able to decipher those methods of communication. </p><p>"With new technology though we're increasingly able to detect and identify these chemical compounds and this is leading to exciting new possibilities for understanding how species interact and evolve," Donihue told Big Think. "As these chemical assays become more common, cheaper, and easier to conduct, I think we're going to find that there are chemical communicators in the plant and animal world that are every bit as exotic and impressive as the bright feathers or intricate birdsongs that are currently the subject of so much research."</p><p>This is likely just the beginning for gaining understanding as to what nonhuman beings, like lizards, are saying to one another right under our noses. </p>This research was published on April 21 in the <a href="https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2656.13205" target="_blank">Journal of Animal Ecology</a>.
Being stuck at home is not as intense as being away from Earth, but there are ways to cope in either scenario.
- While she has not personally been to space, NASA astronomer Michelle Thaller has heard from friends and colleagues what it is like to truly be isolated. Coping mechanisms for these extreme cases can also benefit people here on Earth during the COVID-19 pandemic.
- Setting and maintaining a schedule can help you and your body return to a more normal state, as can finding familiar sensory inputs. For astronauts, that includes Earthly scents like citrus.
- Speaking personally and making a point about silver linings, Thaller shares a story about how COVID-19 has given her more time with her sick husband for what are likely his final days.
Why finding joy is more easily attainable than the pursuit of happiness.
- Joy and happiness are often used synonymously, but designer Ingrid Fetell Lee argues that there is an important distinction between the two: time. Happiness is something that measures how good we feel over time, while joy is about feeling good in the moment.
- Noticing visual and sensorial patterns in the things that brought people joy, Lee was able to identify 10 "aesthetics": abundance, harmony, energy, freedom, play, surprise, transcendence, magic, renewal, and celebration.
- In this video, we learn more about each aesthetic and why focusing on joyful moments is the key to getting the most out of life.