An AI can sniff out certain scents, giving us a glimpse of how our nose might work in detecting them. Thomas Cleland at Cornell University, New York, and Nabil Imam at tech firm Intel created an AI based on the mammalian olfactory bulb (MOB), the area of the brain that is responsible for processing odours. The algorithm mimics a part of the MOB that distinguishes between different smells that are usually present as a mixture of compounds in the air. This area of the MOB contains two key types of neuron: mitral cells, which are activated when an odour is present but dont identify it, and granule cells that learn to become specialised and pick out chemicals in the smell. The algorithm mimics these processes, says Imam. Cleland and Imam trained the AI to detect 10 different odours, including those of ammonia and carbon monoxide. They used data from previous work that recorded the activity of chemical sensors in a wind tunnel in response to these smells. When fed that data, the AI learns to detect that a smell is present based on the sensors responses to the chemicals, and then goes on to identify it on the basis of the patterns in that data. As it does so, the AI has a spike of activity analogous to the spikes of electrical activity in the human brain, says Imam. The AI refined its learning over five cycles of exposure, eventually showing activity spikes specific to each odour. The researchers then tested the AIs ability to sniff out smells among others that it hadnt been trained to detect. They considered an odour successfully identified when the AIs fifth spike pattern matched or was similar to the pattern produced by the sensors. The AI got it almost 100 per cent correct for eight of the smells and about 90 per cent correct for the remaining two. To test how it might identify odorous contaminants in the environment, the researchers blocked 80 per cent of the smell signal to mimic more realistic scenarios. In these tests, the AIs accuracy dipped to less than 30 per cent. I think the link [to the MOB] is quite strong this algorithm might be an explanation to how it works in the human nose, to some abstraction, says Thomas Nowotny at the University of Sussex, UK. But the AIs ability to solve real life problems, such as detecting bombs by picking out hazardous smells associated with them, is still some way off, he says.
newscientist.com, 16 March 2020