April 6, 2007 -- Too Many Old Memories Can It Hard To Make New Memories

I often picture my brain as a dysfunctional office where the neurosecretaries are not exactly shining beacons of efficiency. There’s papers strewn all over the place, files heaped in teetering stacks, and no one ever sorts through the stuff…there’s so much useless information I can never find what I’m looking for.

Turns out that picture might not be so farfetched. Researchers at Columbia University have found that having too many memories cluttering your brain can actually make it harder to remember new things…like where you left your car keys.

It’s been known for awhile that, in mice, storing memories long-term involves making new neurons: destroy an animal’s ability to sprout new brain cells and you mess with its recollections from the past. But the new research shows that if mice have too many new neurons, they have trouble with their working memory: they take longer to find the food hidden in a maze than mice whose neuron-production has been shut down.

So the key to remembering may be: forgetting. With fewer neurons springing up, the animals may be better able to clear their brains of useless old information, which makes it easier for them to access important new information: like where they left their cheese.