Children are very adept at learning new languages or music but as they grow older this capacity declines dramatically.
This is because our capacity for auditory learning declines as we age but now scientists have discovered a way to extend our auditory learning in adulthood and this they discovered with the help of mice.
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Researchers found that my limiting the supply of the function of the neuromodulator adenosine to a part of the brain called auditory thalamus helped preserve the auditory learning ability in adult mice similar to how children learn by hearing sounds in their environment.
The auditory thalamus is the brain’s relay station from where it receives and sends sound signals to the auditory cortex for processing. Both the auditory thalamus and the cortex rely on glutamate to communicate.
It has been known the adenosine reduces glutamate levels by inhibiting its release.
For this study researchers used a variety of methods such as the use of experimental compound FR194921, which selectively blocks the A1 receptor, to demonstrate that inhibiting or blocking A1 adenosine receptor changed how adult mice responded to sound.
When the adenosine was reduced or blocked in the auditory thalamus, adult mice who were exposed to a tone responded to the same tone in a stronger way when it was played weeks or months later.
This is similar to how children pick up a language simply by hearing it spoken by someone else.
The adult mice also gained an ability to distinguish between tones with similar frequencies, an ability they lack normally. The mice also retained improved tone discriminations for weeks.
The researchers found that if the compound FR194921 was paired with sound exposure it rejuvenated auditory learning in mice suggesting that it might be possible to target the A1 receptor in humans for drug development to enhance adult learning.
The researchers also found higher levels of an enzyme (ecto-5′-nucleotidase) and adenosine in the auditory thalamus in mature mice than newborn mice. The enzyme is responsible for adenosine production in the auditory thalamus leading to decline in age-related learning ability. By deleting this enzyme the researchers found that adenosine levels return to the levels found in a newborn mouse.
Therefore researchers are now looking at ways to target this enzyme as another method of extending adult auditory learning.
Further research into this will pave a way for us to learn a new language even as we age. Parlez vous francais?
Source: Science
