Under the Hood

The Science Of Smell: How Do Our Noses Identify Different Odors?

Does cheese smell the same to a mouse as it does to a human? Can a mouse identify cheese if it's mixed in with spaghetti sauce? A new study examining mouse brains, and specifically neural patterns associated with different smells, may shed light on how humans process smells, too.

Researchers created an algorithm that could learn to identify whether a specific odor was present in a mixture of scents. To "train" the algorithm to recognize those patterns, they gathered data from thousands of trials that looked at the neural activation patterns associated with various odors by brain imaging mice. Medical Xpress reported that the results of the study suggest these creatures may be employing a similar algorithm for identifying odors as humans do.

Essentially, one odor causes a particular neural activation pattern, and another odor causes a different pattern," said lead researcher and professor of molecular and cellular biology Venkatesh Murthy said, according to Medical Xpress. "When you start mixing odors, eventually those patterns will overlap. Mice have about 1,000 types of olfactory receptors, but a given odor only activates maybe 10 percent of them. That's sparse enough that, even if you have many scents mixed, they can still parse them out. What the algorithm does is look at those patterns, and even if they are partly occluded (by another odor), it can recognize that a particular pattern is there."

appetizer Results of a mice study have given us insight into odor recognition Photo courtesy of Pixabay

In the future, this study could serve as a model for conducting experiments virtually — like creating an algorithm — before carrying them out in the real world.

"Moving forward, we're excited about this because we want to design experiments for mice and humans that test new questions, for example, what odor experience will best improve smell detection skills, and is supervised learning necessary for improvement?" Murthy said, according to Medical Xpress. "The computer algorithms used in our work can generate strong hypotheses for testing."

Source: Alexander Mathis et al. Reading Out Olfactory Receptors: Feedforward Circuits Detect Odors in Mixtures without Demixing. Neuron . 2016.

Read more:

10 Different Smells Are Detectable By Your Nose: How Did Popcorn Make The List?

Sense Of Smell: Human Nose Can Detect Different Illnesses That Make You Stink

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