As we age, it becomes more expensive for us to learn languages, memorize data … A study by the Medical College of Georgia (USA) suggests that it is becausethe brain loses the ability to filter only what is relevant and to remove old and obsolete information, rather than the difficulties of storing new content.
As explained by neuroscientist Joe Z. Tsien in the magazineScientific Reports, this phenomenon is related to the functioning of thehippocampal NMDA receptorof the brain, which behaves likea switch for learning and memory. It has two subunits: NR2B, which is more expressed in children and allows neurons to communicate for longer; and NR2A, which begins to increase in ratio from puberty and gains ground from NR2B as we age. By simulating adult ratios in mice – that is, more NR2A and less NR2B – the scientists found that the animals were not capable of selectively weakening certain existing neuronal connections (a process called “long-term depression”). However, your brain retains the ability to make neural connections and form short-term memories intact.
“What we see is that si in the brain only synapses are strengthened and are never freed from the noise created by information that is no longer useful“Serious problems arise,” Tsien clarifies. This would leave neurons unable to continue “sculpting” to store new information. And it could be related to Alzheimer’s and senile dementia.
