You know the smell when it rains for the first time after a windy dry day and the smell of that freshness due to raindrops pouring on the dry surface. That smell is not from the water but from the decomposing bacteria and that compound named Geosmin.
The team of researchers was led by Dr.Chris Potter, an associate professor of neuroscience at the Johns Hopkins University School of Medicine. This team worked on geosmin to create a new genetic technique in flies which helped scientist to correlate the connection between smell and its effect on behaviour.
This team termed this technique “Olfactogenetics”. They explained the working as same as the principle of popular neuroscience technique to genetically engineer specific neurones to fire off signals when in contact with light. But this time instead of using light, Olfactogenetics uses geosmin.
The unique thing about goes in is it can be detected by only one type of neurone while most odours are detected by several types of smell-sensing neurones. This unique ability of geosmin helped scientist to genetically modified some neurones to disable the neurones which can detect geosmin. Scientist released geosmin in the air to track down the neurones which are detecting this compound.
Olfactogenetics does not use light but instead, it uses an odour. This allowed the researchers to see the function of neurones at the time of sensing a smell, without any fear of overstimulation.