Engineering Science

The Conversation: From odor to action – how smells are processed in the brain and influence behavior

Anonymous — Wed, 26 Jan 2022 17:19:35 +0000

The Conversation: From odor to action – how smells are processed in the brain and influence behavior Anonymous (not verified) Wed, 01/26/2022 - 10:19

A dog raises its nose in the air before chasing after a scent. A mosquito zigzags back and forth before it lands on your arm for its next meal. What these behaviors have in common is that they help these animals “see” their world through their noses.

While humans primarily use their vision to navigate their environment, the vast majority of organisms on Earth communicate and experience the world through olfaction – their sense of smell.

We are members of Odor2Action, an international network of over 50 scientists and students using olfaction to study brain function in animals. Our goal is to understand a fundamental question in neuroscience: How do animal brains translate information from their environments to changes in their behaviors?

Here, we trace the interconnections between smells and behaviors – looking at how behavior influences odor detection, how the brain processes sensory information from smells and how this information triggers new behaviors.

Visualizing what smells look like helps researchers design technologies that detect odors as well as a dog can.

Detecting odors in the environment

When the odor of a flower is released into the air, it takes the shape of a wind-borne cloud of molecules called a plume. It encounters physical obstacles and temperature differences as it flows through space. These interactions create turbulence that splits the odor plume into thin threads that spread out as the scent moves away from its source. These filaments eventually reach an animal’s nose or an insect’s antenna.

Odors that are broken up into filaments present a challenge to animals using them to find food or mates or avoid threats. It becomes difficult to predict precisely where the odor is coming from. Is the source directly ahead, to the left or right, above or below?

This video by the Crimaldi Laboratory of the �鶹��Ƶ shows an odor plume developing behind a moving source over time. The source moves up and down from the left side, and the odor flows from left to right.

To work around this, animals have evolved what are called active sensing behaviors that improve their ability to detect and find odors in the environment.

When a fly detects the smell of fruit or a mosquito detects carbon dioxide from a possible host, for example, both insects first move upwind to get closer to the odor of the food source. They then move in a meandering, back-and-forth motion called casting to find more odor threads before surging upwind again. If they lose the scent, they’ll start casting again until they find the scent. Larger animals, such as mice and dogs, also alternate between more directed movements and more exploratory searching actions.

Animals also move their noses and antennae to improve the chances that they’ll encounter an odor. This is why dogs raise their noses in the air to increase the amount of odor they can sniff, and why insects move their antennae to stir up and penetrate the air to make better contact with odor molecules.

Once information from odors tell the animal that they’re close to the source, visual searching then comes into play.

Making sense of odors

When an animal comes into contact with an odor plume, it detects the presence of these odor molecules through tiny proteins called odorant receptors. These receptors are embedded in the sensory neurons lining its nasal cavity or antennae.

Each sensory neuron contains only one type of odorant receptor. And each type of odorant receptor has a different shape and set of chemical properties that determine which odors can bind to and activate it. Most of these receptors recognize multiple odors, and most odors can bind to multiple different receptors. What encodes the identity of a specific odor in the brain is determined by which combination of receptors are activated, and their relative strength of activation.

This video from the Wachowiak Lab at the University of Utah shows the activity of the olfactory bulb in a mouse brain as the mouse is exposed to different odors. Different odors make different combinations of neurons in the olfactory bulb light up.

An animal like a mouse has about a thousand types of odorant receptors. Having a large number of these receptors with diverse shapes allows the system to detect and distinguish between a very large number of chemically unique odors, including ones the animal has never encountered before. Most odors in the environment are often a mix of many different types of molecules. The smell of some flowers can be a blend of over 100 different chemical compounds.

Once an odor molecule binds to a receptor, sensory neurons send specific electrical signals into compartments of the brain called olfactory glomeruli. Different odors elicit distinct patterns of electrical activity across these regions, and this generates a specific neural representation of the odor in the brain.

An important step toward understanding olfaction is figuring out how different classes of odors map to different patterns of electrical signals in the brain.

Neuroscientists hypothesize that as these signals undergo successive stages of processing deep in the brain, sensory representations of odor are reformatted in ways that extract information most useful to survival. This could be whether the smell is coming from something nutritious, indicating a potential source of food, or it could help the animal identify whether the smell is coming from a potential competitor or predator.

These reformatted sensory representations form the basis for how animals perceive smell and determine what actions they take in response to this information.

From odor to action

Once information about a particular odor reaches the brain, it often elicits both instinctual and learned behaviors. Odors that signal danger may trigger the animal to freeze or run away, while odors from a member of the same species may trigger the animal to mark its territory or initiate courtship.

In many cases, animals perform these tasks with incredible precision and effectiveness. It’s still common to use search dogs to find lost people and pigs to find truffles because available technologies aren’t capable of performing as well.

Animals achieve this level of performance not just because they’re able to detect and identify an odor. They’re also able to integrate odor features, like how intense the odor smells, with environmental clues, like wind direction, and internal cues, like hunger. All this information comes together to generate specific sequences of behaviors such as “face into the wind and then walk forward.”

Dogs rely on smells to provide long-distance information. Humans, on the other hand, use smells for short distances.

To understand how odor guides these behaviors, scientists measure or manipulate an animal’s brain activity as they perform specific actions. This is done using imaging, electrophysiology or optogenetics, which selectively activates specific neurons by shining a light on them. These approaches allow researchers to understand how patterns of brain activity shift when an animal changes its behavior to chase after an odor, or how environmental and internal cues combine to produce a best guess on the location of its next meal.

Leading science and technology by the nose

The olfactory system offers a unique opportunity to understand how the brain processes environmental information and translates it to behavior. Compared to other areas of the brain, the olfactory circuit is simpler in structure and uses fewer stages of processing. Its relative simplicity is what allows scientists like us to study it from end to end and learn how the brain works as a whole.

Robots may one day be able to replace dogs in search and rescue situations.

Understanding brain function through the lens of olfaction could also pave the way for transformative developments in engineering, neuroscience and public health. Our research should accelerate the development of robots with electronic noses that can use odors to search for chemical weapons, underwater oil spills and natural gas leaking from pipelines in environments where it may be tedious or dangerous for humans or animals to go. Robots might also be able to search for missing people or disaster victims, something typically done with trained dogs.

An exciting future in scientific and medical development, we believe, is right under our noses.

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McKnight named a CU Distinguished Professor

Anonymous — Wed, 01 Dec 2021 18:35:52 +0000

McKnight named a CU Distinguished Professor Anonymous (not verified) Wed, 12/01/2021 - 11:35

Jeff Zehnder

McKnight in Antarctica.

Diane McKnight is being recognized with the highest honor bestowed upon faculty in the University of Colorado system: Distinguished Professor, which is awarded to faculty for exemplary performance in research, teaching, and service.

A professor in the Department of Civil, Environmental and Architectural Engineering; the Environmental Engineering Program; and the Institute of Arctic and Alpine Research, McKnight has spent her career studying ecological, biogeochemical and hydrologic processes in lakes, streams and watersheds, primarily in polar and mountain regions.

“I’ve been interested in hydrology and ecology since I was in college in the ’70s,” McKnight said. “It’s fascinating work and directly impacts our understanding of water quality and the influence of climate and hydrology.”

Her research has dramatically expanded knowledge about the relationship between natural organic matter and heavy metals in streams and lakes and led to her election to the National Academy of Engineering in 2012.

Much of her field work has been in extreme environments, especially polar regions – she has been to Antarctica more than two dozen times.

“The lessons that we learn in Antarctica get plugged in more broadly. The algae growing in streams there are very similar to algae growing in Colorado, but we can understand more clearly what’s happening there because there is no signal coming in from plants in the meadow or in the forest because there aren’t any meadows or forests,” she said. “They’re like naked streams. We can learn about fundamental processes.”

McKnight is one of the founding principal investigators of the McMurdo Dry Valleys Long Term Ecological Research Program in Antarctica, and she serves as chair of the National Science Foundation’s LTER Science Council.

“As we think about green engineering for green infrastructure, people are putting more value on sustaining rivers to help deal with floods in cities and various pollution issues. These ecosystem concepts are also very relevant to dealing with hazardous algal blooms,” she said. “There’s a realization that some of the water challenges can’t just be addressed by treating drinking water at the utility plant. We need a more holistic approach, a bigger view.”

McKnight earned her PhD in environmental engineering at the Massachusetts Institute of Technology in 1979 and spent 17 years at the U.S. Geologic Survey, conducting field and laboratory research, before joining CU Boulder in 1996.

“I was at the USGS and had grad students working in my lab from CU Boulder, Colorado State, and the School of Mines. I really wanted to teach stream ecology. It’s an exciting field and the students are excited, too,” she said.

She was one of the founding faculty members of CU Boulder’s Environmental Engineering Program when it began in 1998 and has been part of its growth as an important discipline in the College of Engineering and Applied Science.

“We have as many students in a single environmental engineering class now as we had in the whole program when it started. It’s to CU Boulder’s great credit that this program has been supported and evolved,” she said. “I am glad to be part of how we deliver this curriculum and train our students. I am so indebted to my colleagues at INSTAAR and in environmental engineering who have been very supportive.”

Although McKnight is in the middle of a semester-long sabbatical, conducting remediation research on the hydrology of the Florida Everglades, she is eager to be back on campus for the spring 2022 semester.

“It’s a great privilege to teach a class and to advise and mentor students. You’re providing scope, being open to their ideas and also helping them stay focused and to take setbacks in stride,” she said. “They are so motivated and unafraid. It’s inspiring.”

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McKnight named a distinguished professor

Anonymous — Fri, 05 Nov 2021 18:10:12 +0000

McKnight named a distinguished professor Anonymous (not verified) Fri, 11/05/2021 - 12:10

A member of the CU faculty since 1996, McKnight has served the CU community in a number of departments including the Department of Civil, Environmental and Architectural Engineering; the Environmental Studies Program, INSTAAR; the Center for Water, Earth Science and Technology; Hydrologic Sciences Graduate Program; and the Mountain Research Station.

Her scholarly work explores ecological, biogeochemical and hydrologic processes in lakes, streams and watersheds, primarily in polar and mountain regions. These field studies analyze the dynamics of these systems and apply innovative measurement tools in harsh environments. She is a leader in measuring dissolved organic matter from the spectra of its fluorescence. Her top paper has been cited over 2,000 times. Her work has made her a leader in the National Science Foundation’s Long-Term Ecological Research Network, and she has served as a principal investigator in a number of projects since 1997.

McKnight’s work has transformed her field and has enhanced scientific understanding to the effects of climate change. She has been active in public outreach programs meant to translate science to the public, including her work on a children’s book series. An outstanding teacher and mentor of graduate students, she has served CU as a curriculum innovator in a wide variety of disciplines. Since 1996, McKnight has been the principal advisor to 24 PhD students. Not only has she led groundbreaking research, furthered public knowledge and served the CU community, she has prepared the next group of researchers to do the same.

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Major research center for green building technology launches at CU Boulder

Anonymous — Wed, 22 Sep 2021 14:17:10 +0000

Major research center for green building technology launches at CU Boulder Anonymous (not verified) Wed, 09/22/2021 - 08:17

Jeff Zehnder

A major research center for sustainable building technology has been founded at the �鶹��Ƶ.

The Building Energy Smart Technologies (BEST) Center is a new, five-year multi-university initiative funded by the National Science Foundation to advance sustainable building projects ranging from HVAC manufacturing, to smart glazing for windows, building controls, insulation, as well as solar installations.

“This is a long term commitment to solve industry problems and make buildings adaptive,” said Moncef Krarti, director of the center and a professor in the Department of Civil, Environmental and Architectural Engineering. “Many western countries want to be net zero in carbon emissions by 2050. That’s a significant challenge. To achieve that, we need a new set of innovative and smart technologies. We have to combine energy efficiency, reduce demand, and deploy renewable energy into buildings so they can be a net positive, actually producing energy, not just consuming power.”

The project is focused on business collaboration, directing research into areas needed for the construction industry and building retrofits. The new center will operate under the NSF Industry-University Cooperative Research Centers model. This setup is designed to help startups, large corporate partners and government agencies connect directly with university researchers to solve common research obstacles in a low-risk environment. The aim is to develop new technology faster and build out the U.S. workforce in critical areas.

“This will be a really interactive process between industry and universities with what problems to solve. Each project we take on will have an industry sponsor,” Krarti said.

The NSF grant will provide $1.5 million over five years, matched by industry associates for a total of at least $3.0 million. Ten industry partners are already onboard with the initiative.

CU Boulder is the lead for the center, with the City College of New York as a partner site, offering the opportunity research and test new building technologies in the largest metropolitan area in the United States.

The work in New York will be led by Jorge González, Presidential Professor of Mechanical Engineering at CCNY.

“This is a major milestone and opportunity, as it validates our long-term efforts in research and education on building systems as supporting activity to our city,” González said. “We will be providing engineering and technology solutions to connect the outdoors environment to the indoors of buildings to enable smart and sustainable responses.”

In addition to meeting emissions goals, new smart and adaptable technologies in the built environment will provide responses for increasingly frequent extreme weather events due to the rapidly changing climate. The work will also direct attention on emerging challenges in the building sector due to pandemics and health crises such as those caused by COVID-19.

“It’s hard for industry to fund research, but this center is a vehicle to that collaboration. It’s a big deal,” Krarti said. “We spend 80% of our time in buildings. We need to make sure buildings are sustainable and healthy as well as comfortable.”

In addition to Krarti and Gonzalez, other CU Boulder faculty partners include Kyri Baker, Gregor Henze, Wil Srubar, John Zhai, and Wangda Zuo, all in the CU Boulder Department of Civil, Environmental and Architectural Engineering, as well as Michael McGehee in the Department of Chemical and Biological Engineering.

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Zuo an International Building Performance Simulation Association Fellow

Anonymous — Thu, 26 Aug 2021 21:56:07 +0000

Zuo an International Building Performance Simulation Association Fellow Anonymous (not verified) Thu, 08/26/2021 - 15:56

Associate Professor Wangda Zuo has been elected a fellow of the International Building Performance Simulation Association.

IBPSA is a non-profit international society of building performance simulation researchers, developers and practitioners dedicated to improving the built environment.

Zuo is a leading researcher in building system modeling and indoor environmental modeling. He has spent nearly 20 years in building modeling and simulation with significant contributions in the development of various open source software including Fast Fluid Dynamics model, Modelica Buildings Library, Modelica Smart and Connected Community Library, and Modelica Net Zero Energy Community Library.

He has been serving as IBPSA Treasurer and Affiliate Director representing the United States since 2016. He is the founding Chair of the IBPSA-USA Research Committee (2014-2018) and former Chair of ASHRAE TC 4.10 Indoor Environment Modeling (2019-2021).

Zuo joined the Department of Civil, Environmental and Architectural Engineering at CU Boulder in 2017 and also holds an appointment in the Buildings and Thermal Sciences Center at the National Renewable Energy Laboratory.

His election will be officially recognized at the IBPSA Building Simulation 2021 conference in Bruges, Belgium, being held Sept. 1-3, 2021.

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International research partnership aims to reduce residential energy consumption

Anonymous — Thu, 22 Jul 2021 17:26:15 +0000

International research partnership aims to reduce residential energy consumption Anonymous (not verified) Thu, 07/22/2021 - 11:26

Researchers at CU Boulder are working with colleagues in Ireland to help policymakers and other stakeholders reduce residential energy consumption and the related greenhouse gas emissions that come from it. The project ultimetly aims to provide leaders with the data-driven tools needed to make decisions about retrofitting residential energy solutions.

The CU Boulder team is led by Associate Professor Wangda Zuo from the Department of Civil, Environmental and Architectural Engineering.

“Our team will be leading the building energy modeling and machine learning aspect of the project,” Zuo said. “The hope is the information we generate together with the rest of the team will lead to better decisions at the local and national levels as society begins seek and install green solutions for the built environment.”

The work – titled “Intelligent Data Harvesting for Multi-Scale Building Stock Classification and Energy Performance Prediction” – is funded by the National Science Foundation, the Science Foundation Ireland, and the Department for the Economy in Northern Ireland as part of the U.S.-Ireland Research and Development Partnership.

The partnership is a unique initiative involving funding agencies across three jurisdictions: the United States of America, Ireland and Northern Ireland. The overall goal is to increase research and development collaboration amongst researchers and industry across those jurisdictions – generating valuable discoveries and innovations that are transferable to the marketplace or will lead to enhancements in health, disease prevention or health care. Residential buildings account for 14% to 27% of greenhouse gas emissions in the three jurisdictions, making it an important area for collaboration and interdisciplinary research.

Eventually, the team will ask the U.S. Department of Energy's Pacific Northwest National Laboratory to adopt the research results into their national building energy policy analysis for 139 million homes. The Northern Ireland Housing Executive will also utilize this work to help predict decarbonization pathways for their housing stock of nearly 86,000 homes – about 10% of the housing stock in Northern Ireland. And the work will also assist the Sustainable Energy Authority of Ireland with its retrofit plan of 500,000 homes in the Republic of Ireland.

The total funding for the project is about €1 million euros, or about $1.18 million dollars, across the three nations and work will begin in September, running for three years. Partner institutions on the project include University College Dublin and Ulster University.

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Engineering Science

The Conversation: From odor to action – how smells are processed in the brain and influence behavior

More than 140,000 readers get one of The Conversation's informative newsletters

Detecting odors in the environment

Making sense of odors

From odor to action

Leading science and technology by the nose

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McKnight named a CU Distinguished Professor

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McKnight named a distinguished professor

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Major research center for green building technology launches at CU Boulder

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Zuo an International Building Performance Simulation Association Fellow

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International research partnership aims to reduce residential energy consumption

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