physical and mental health.

It can relieve stress, lower blood pressure and lift someone's mood.

But only in the last few years have neuroscientists taken a serious look

at the changes in brain structure underlying some of meditation's benefits.

Like everything else we do, meditation rewires our neural circuits.

Pruning away the least used connections and strengthening the ones we exercise most.

Studies looking for signs of these changes usually focus on "mindfulness meditation"

which challenges people to keep their attention fixed on the thoughts and

sensations in the present moment.

Scientists aknowledge that these studies are small and not ideally designed, but at this

point researchers have gathered enough evidence to be confident that

their findings are not just flukes.

Experiments suggest that Buddhist monks have really robust connections

between scattered regions of their brains, which allows for more

synchronized communication.

Expert meditators also seem to develop an especially

wrinkly cortex: the brain's outer layer.

We depend on the cortex for many of our most sophisticated mental abilities

like abstract thought and introspection.

Several studies have confirmed that meditation can increase the

volume and density of the hippocampus: a seahorse- shaped area

of the brain in the middle of the skull that is absolutely crucial for memory.

And although areas of the brain responsible for sustaining attention

usually shrink as we age, meditation counteracts this decay.

An increasing number of studies show that meditating for as little as

12 to 20 minutes a day for several weeks can sharpen the mind.

In these studies, meditators have scored higher on tests of attention

and working memory, which is the ability to temporarily

store and manipulate information in one's mind.

Some lifelong meditators in their 50s and 60s can even

outperform twenty-somethings in tests of visual attention.

So if you're interested in trying meditation, you should probably start

as soon as possible.

For Scientific American's Instant Egghead,

I'm Ferris Jaybr.