John Hamilton

Then, around age 66, connections start to weaken, a process that accelerates after age 83.

John Hamilton, NPR News.

Researchers at the University of Cambridge in the UK studied the brains of more than 3,800 people from newly born to age 90.

The team used MRI to see how the brain's wiring changed over that span.

And they identified four time points when the brain reconfigures.

At about age 9, the brain ends its childhood phase, which prunes away unneeded connections between neurons.

It also begins an adolescent phase of optimizing the connections that remain.

At 32, the brain enters a long period of stability.

Then, around age 66, connections start to weaken, a process that accelerates after age 83.

John Hamilton, NPR News.

That's because this class of drugs, called GLP-1, affects an area of the brain stem known as the vomit center.

So researchers did an experiment that kept the drug from reaching this brain area in mice.

Warren Yakowich of the University of Michigan says that kept the mice from feeling sick, but also meant they didn't lose weight.

Even so, companies that sell GLP-1 drugs are still trying to get rid of this side effect.

It's a major reason many patients stop taking the medications.

John Hamilton, NPR News.

About half the people who take these drugs feel queasy.

That's because this class of drugs, called GLP-1, affects an area of the brain stem known as the vomit center.

So researchers did an experiment that kept the drug from reaching this brain area in mice.

Warren Yakowich of the University of Michigan says that kept the mice from feeling sick, but also meant they didn't lose weight.