The sense of smell and sense of hearing are linked to each other

If the sense of smell deteriorates, it may be an indication of how it will go for the brain's other functions during aging. The relationship serves as an early warning clock for upcoming dementia and Altzheimer's disease.

- The odor areas are affected at a very early stage before general reductions in function occur. If the sense of smell deteriorates, then other cognitive intellectual abilities will be impaired perhaps five, ten years later, says Jonas Olofsson, psychologist and neuroscientist at Stockholm University.

- Many people go to doctors and say, "I have lost my taste buds", but in fact it is the sense of smell that has deteriorated. Wine does not give the same enjoyment as before and food and well-prepared food do not taste the same as before, explains Jonas Olofsson.

It is already known that the parts of the brain that record smell and hearing communicate with each other in humans. It works so that when we hear, for example, the word "strawberries", the auditory brain is activated. This part, in turn, activates the scent brain, and makes it prepared for the scent of strawberries.

In the case of dementia, this communication is weakened or disappears completely and this means that fragrances cannot be matched with words.

The researchers at Stockholm University have now examined the brain of rats and can find that the rat's brain functions in the same way as the human brain. Jonas Olofssons describes it as the scent part and the hearing part swing in tempo.

Since a lot of dementia research is conducted with the help of rats, the new discovery will make it possible to study new details of the aging of the brain. It opens up new opportunities to study dementia and develop new medicines in the future.

- The particular sense of smell of the rat brain is a particularly good method for trying new medicines that can slow down the development of, for example, Altzheimer's disease.