Induced Smells
In a recent, incredibly small blind trial, researchers were able to induce smells in two human test subjects using ultrasound.
In the human body, smells are processed in a neural structure located in our forebrain called the olfactory bulb. This structure then sends processed smell information to other parts of the brain, like the amygdala, orbitofrontal cortex, and hippocampus, which allows smells to influence emotion and learning, and imbues memories with smell-related data.
Previous experiments have shown that electrical stimulation of the olfactory bulb can induce olfactory hallucinations: the sense of smelling things that aren’t there. The folks behind this new trial wanted to see if the same could be accomplished using ultrasound, instead, based on a previous experiment in which they found they could induce a sense of motion via similar means.
After quite a lot of fiddling to ensure the ultrasound was aimed at the right place and the subjects were at no risk of harm, the researchers were able to reliably induce four different false-smells using this method: the sense of inhaling oxygen-rich fresh air, the smell of old, fruit peel-laden garbage, the sense of smelling ozone, and a campfire-like smell of burning wood.
