Now, two neuroscientists from the Salk Institute and UC San Diego have discovered that at least six types of mammals -- from mice to cats -- distinguish odors in roughly the same way, using circuitry in the brain that's evolutionarily preserved across species.
"The study yields insights into organizational principles underpinning brain circuitry for olfaction in mammals that may be applied to other parts of the brain and other species," says Charles Stevens, distinguished professor emeritus in Salk's Neurobiology Laboratory and coauthor of the research published in the July 18, 2019 issue of Current Biology.
Brief - Study - Size - Components - Network
In brief, the study reveals that the size of each of the three components of the neural network for olfaction scales about the same for each species, starting with receptors in the nose that transmit signals to a cluster of neurons in the front of the brain called the olfactory bulb which, in turn, relays the signals to a "higher functioning" region for odor identification called the piriform cortex.
"These three stages scale with each other, with the relationship of the number of neurons in each stage the same across species," says Shyam Srinivasan, assistant project scientist with UC San Diego's Kavli Institute for Brain and Mind, and the paper's coauthor. "So, if you told me the number of neurons in the nose, I could predict the number in the piriform cortex or the bulb."
Study - Builds - Research - Duo - Process
The current study builds on research by the same duo, published in 2018, which described how mouse brains process and distinguish odors using what's known as "distributed circuits." Unlike the visual system, for example, where information is transmitted in an orderly manner to specific parts of the visual cortex, the researchers discovered that the olfactory system in mice relies on a combination of connections distributed across the piriform cortex.
Following that paper, Stevens and Srinivasan...
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