By Kelsey Simpkins

Principal investigator
John Crimaldi

Funding
National Science Foundation (NSF); Canadian Institutes of Health Research; UK Research and Innovation Medical Research Council

Collaboration + support
Arizona State University; Caltech; Duke University; Francis Crick Institute; Lehigh University; McGill University; NYU School of Medicine; Penn State University; Salk Institute; Scripps Research; University of Hertfordshire; University of Pittsburgh; University of Utah; Weill Cornell Medical College; and Yale University

New international network explores how odors lead to actions

CU Boulder is leading agroundbreaking new internationalresearch network dubbed, which includes 16scientists from 16 institutionsaround the world working togetherto better understand the brain andits evolution by reverse-engineeringhow it interprets odors. Part ofthe Next Generation Networks forNeuroscience (NeuroNex) Program,the five-year project is aimed atunderstanding how animals useinformation from odors in theirenvironment to guide behavior,with far-ranging implications for ourunderstanding of the human brain.

The network will examine all the stepsinvolved in how an odor stimulusis encoded by the brain and thenactivates the motor circuits to producea behavioral response in an animal.The model species they are workingwith, including fruit flies and mice, willhelp the researchers understand thesesame steps in humans.

“The chemical sensing process (i.e.,smell) evolved in the very earliestlife forms on Earth,” said JohnCrimaldi, lead principal investigatoron the network and professor in theDepartment of Civil, Environmentaland Architectural Engineering. “Theidea here is that all brain evolutionhas taken place in the presence ofchemical sensing. And so it’s thoughtto be a primal portal from which toview brain function.”

While Crimaldi and CU Boulder havepreviously received significant awardsto research how animals find thesource of an odor, this project is muchbroader and aims to understand thewhole brain and the mechanism thatgoes into a behavioral response tosmelling something.

John Crimaldi odor research

Smell is the least understood sense,and humans have struggled toreplicate odor-based searches withmachines, Crimaldi said. Doing so,however, would allow robots to takeover treacherous duties instead ofhumans or dogs, unlocking a newarea of advancement for autonomoussystems. These robots could oneday rescue a person buried in anavalanche, locate valuable naturalresources, or find chemical weaponsand explosives on their own,for example.

This network is among the largestthe College of Engineering hasever been involved in, said KeithMolenaar, interim dean of the Collegeof Engineering and Applied Science.He said the work would result intransformational research around ourunderstanding of the brain that couldalso lead to cures for diseases thatconnect to our sense of smell—oreven understanding why loss of smellis a symptom of some diseases likeCOVID-19.

As an engineer, Crimaldi said henever expected to end up workingin neuroscience, but it turns outa lot of engineering is involved inunderstanding what odors look like.He currently studies fluid mechanicsfrom a theoretical perspective,using lasers in a nonintrusive wayto measure flows—like odors—through air and liquids. He’s lookedat everything from why coralreproduction underwater is successfulto how animals can tell where a smellis coming from.

“Life forms have evolved to takeadvantage of specific opportunitiesand constraints that are imposed bytheir physical environment,” Crimaldisaid. “I like to say we don’t justuse physics to understand biologyor ecology, or the brain. We alsouse evolutionary processes thathave evolved in animals to help usunderstand details of what’s going onin the physical world.”