If you're having trouble taking in new information as you get older, don't fret. It's not that age is making you more stupid or slow, but that your brain is already so full of information — you genius, you — that it can't make room for anything new.
After studying mice with brains that had been genetically altered to resemble an adult human's, neuroscientists at the Medical College of Georgia at Georgia Regents University have recently discovered that the human brain does not necessarily decrease in its ability to make the strong synaptic connections that allow us to learn as we get older. Rather, as the brain ages, it finds it harder to weaken older memories and solidify new ones.
From the New York Times:
Think of it as writing on a blank piece of white paper versus a newspaper page, said the lead author, Joe Z. Tsien. "The difference is not how dark the pen is," he said, "but that the newspaper already has writing on it."
With their mice subjects, the neuroscientists manipulated NR2A and NR2B, the two proteins responsible for creating new connections in the brain. When the mices' brains produced more NR2A, the protein more prevalent in the human postpubescent brain (prior to puberty, the brain produces more NR2B), the mice had no problem creating new short term memories, but struggled to loosen their hold on older long term memories.
"What our study suggests," Dr. Tsien said, "is that it's not just the strengthening of connections, but the weakening of the other sets of connections that creates a holistic pattern of synaptic connectivity that is important for long-term memory formation."
So it's going to be an uphill battle for you, in your decrepit old age, to learn French or remember the names of everyone in your office, but you'll never forget all those Heathers quotes that you committed to memory in eighth grade. Worth it!