Introducing the brain: algorithm creating odors (Introduction)

by David Turell , Monday, January 10, 2022, 20:22 (1046 days ago) @ David Turell

Has to do with ON and OFF neurons:

https://medicalxpress.com/news/2022-01-surprisingly-simple-arithmetic.html

"Why don't other smells or different environmental factors "get in the way," so to speak, of the experience of smelling individual odors? Researchers at the McKelvey School of Engineering at Washington University in St. Louis turned to their trusted research subject, the locust, to find out.

"What they found was "surprisingly simple," according to Barani Raman, professor of biomedical engineering. Their results were published in the journal Proceedings of the National Academy of Sciences of the United States of America.

"The algorithm turned out to be very simple to interpret. It exploited two functional types of neurons: there are ON neurons, which are activated when an odorant is present, and there are OFF neurons, which are silenced when an odorant is present but become activated after the odor presentation ends.

"'You can think of the ON neurons as conveying 'evidence for' an odor being present, and OFF neurons as 'evidence against' that odor being present," Raman said. To recognize an odorant's presence, researchers simply needed to add evidence for the odorant being present (i.e. add the spikes across all ON neurons) and subtract evidence against that odor being present (i.e. add the spikes across all OFF neurons). If the result was above a certain threshold, machine learning would predict the locust smelled the odor".

Comment: smelling odors is the result of hundreds of receptor spots in humans with many more in dogs.