There is no other sense so powerfully tied to the foundations of emotion and memory as the sense of smell. Whether it is the smell of freshly-brewed coffee or the soporific tones of lavender, we are influenced by scents occurring and blossoming all around us.
That is why the loss of smell or anosmia is so damaging to our mental health. One of the symptoms of Covid-19 was indeed this sacred sense which is so crucial to our sense of both emotion and memory.
New research has now added to our understanding of smell.
Researchers from the University of Tokyo built a specially-designed machine that delivered 10 different scents in an accurate and systematic way. To measure the effects of the smell on the brain, the researchers used innovative technology utilising scalp-recorded electroencephalogram (EEG) caps. Using this system the researchers could establish what happened temporally when the scents were registered by the brain.
The researchers found some interesting results.
One of the results was that the brain registered the scent several hundred milliseconds before the participant themselves noticed the smell.
Unpleasant smells registered 300 milliseconds after onset, whereas pleasant smell took a little longer appearing 500 milliseconds after onset.
From about 600 milliseconds other areas of the brain such as emotional and memory regions became most active in processing these scents.
Why is this research relevant?
It’s unfortunate to ask this question, as all scientific research is part of the general quest of discovery, finding out how and why things work as they do. Nevertheless, this research may help elucidate the connections between neurodegenerative disorders such as Alzheimer’s and Parkinson’s in which the loss of the sense of smell can be an early warning sign.