People who pay attention to its sense of smell is not what it used to, may need to train the sense of smell. Exercise can increase the sense of smell has decreased function.

The study was conducted by Drs Julie Chapuis and Donald A Wilson from New York University (NYU) Langone School of Medicine. The results of these studies have been published online in Nature Neuroscience on 20 November 2011 edition.

Researchers hope their findings will help develop new ways to reduce the loss of smell that occurs with age or disease.

Humans detect odor molecules because it interacts with the nerves in the nose which send impulses to the olfactory structures (olfactory bulb). The structure is located below the frontal cortex at the front of the brain.

Olfactory bulb also connect directly with other parts of the brain like the amygdala that controls emotions, and the high level areas such as prefrontal cortex. The prefrontal cortex has important functions such as planning, thinking, organizing and making choices.

Decreased sense of smell is associated with diseases such as Alzheimer’s disease, Parkinson’s disease, schizophrenia and even normal aging. But the cause remains unknown.

However Chapuis and Wilson reported that they had found in brain regions associated with decreased sense of smell. Both researchers also showed that training can increase or decrease the sense of smell. It depends on the sense of smell.

“Of all the senses, the sense of smell is unique because unlike the information from the eyes and ears have been through a lot of connections to reach the frontal cortex, olfactory system involves only two connections. And it has a direct pathway from the environment through the nose into our memory,” said Wilson, a professor of child and adolescent psychiatry at NYU Langone Medical Center as reported from MedicalNewsToday.

Researchers placed mice in individual boxes with a hole the size of a muzzle rats each on three walls. Each using a slight variation on a mixture of 10 odors, based on chemicals from fruits, oil, and cleaning materials.

Researchers repeated the experiment with different smells, and observing the mice.Results showed that rats easily able to distinguish one odor from another chemical when it was replaced in the mixture. But the rats could not distinguish when one chemical is removed and no replacement.

In the next phase of this study, rats anesthetized and put electrodes into their brains while they have to smell. So it can see the pattern of electrical activity generated in the brain are affected.

Any odors produced different patterns of activity in the olfactory bulb, but in the cortex Piriform (olfactory), one centimeter area of ??the cerebral cortex, different patterns when rats were able to distinguish odors. But the smell is identical when mice are unable to distinguish.

The training can effectively improve the sense of smell a rat, and it is reflected in the pattern of electrical activity in their Piriform cortex, which showed identical responses to both odor.

Rats were given extensive training in overlap with a complex mixture of odors that can demonstrate the ability mebedakan odor and increase the separation of cortical ensemble piriformis.

In contrast, behavioral training to ignore differences that are usually detected between the overlapping mixture separation resulted in disorders of cortical ensemble patterns and impaired differentiation Piriform odor.

Loss of sense of smell can reflect the real damage to the sensory system, in some cases can be a problem. Training to sharpen the smell can help repair damaged sense of smell due to a broken nose.