Flies have evolved an energy-efficient olfactory system as a result of evolution.
A flower’s unique scent… coffee’s recognizable fragrance… the hazards of breathing cigarette smoke Whether it’s colors processed by our eyes or specific pitches perceived by our ears, sensory systems have developed to give us with quick, highly calibrated information about the world around us.
Our sensory systems process this deluge of information. Scientists have discovered maps that show how sensory neurons are grouped depending on their function in order to digest information properly. The sense of smell, on the other hand, has yet to be linked with this kind of functional map. Researchers from the University of California, San Diego, have recently defined a scent sensory map in fruit flies. The scientists found how and why the fly olfactory system is structured on the surface of fly antennae, where odorous molecules are sensed.
A team led by graduate student Shiuan-Tze Wu from the laboratory of Biological Sciences Associate Professor Chih-Ying Su released this new map in the Proceedings of the National Academy of Sciences. The research looks at how the olfactory receptor neurons, which detect scent, are structured inside the sensory hairs of the fly.
“Hundreds of odorous compounds are continually bombarding us in our surroundings,” said Su, the study’s corresponding author. “We’ve identified a peripheral mechanism that allows the fly to understand such incredibly complicated inputs.”
The researchers show that the fruit fly’s olfactory system, which Su characterized as “simple but elegant,” is organized to allow the insect to make fast evaluations of aromas in an innovative fashion that avoids metabolically costly synaptic connection. Instead, the insect’s olfactory receptor neurons (ORNs) communicate with one another through electrical connections. The researchers write in their report that this provides an energy-saving, “metabolically inexpensive” technique to analyze “meaningful odor mixtures without necessitating costly synaptic computation.”
The paper explains how two ORN compartments are set up to detect stimuli with opposing implications for the fly. To swiftly and effectively analyze complex scents in their surroundings, such signals either encourage or hinder particular actions.
According to the article, “this structure offers a way of both evaluating and shaping the competing sensory inputs conveyed to higher brain areas for further processing.”
The Su team cooperated on this research with UC San Diego Neurobiology Assistant Professor Johnatan Aljadeff, who developed a mathematical model that describes how electrical interactions aid in the extraction of pertinent data.
“We discovered that nature has selected a particular manner of arranging this sensory assay by asking questions about the functional significance of this structure,” Aljadeff stated. “There might be future technical applications if we can comprehend the concept of this sort of processing.” Aljadeff’s research is supported by a Defense Advanced Research Projects Agency (DARPA) Young Faculty Award.
Wu, the study’s first author, is happy to have been a member of the team that achieved this important finding. He praises the elegance with which fly ORNs calculate opposing cues, drawing analogies with how our visual systems contrast color hues to help us distinguish between red and green, for example.
Shiuan-Tze Wu, Jen-Yung Chen, Vanessa Martin, Renny Ng, Ye Zhang, Dhruv Grover, Ralph Greenspan, Johnatan Aljadeff, and Chih-Ying Su are among the authors.