Little things, like taking a shortcut through the park on your way to work each day can make a big difference

to your mental health. Find your little big thing

little big thing at every mind matters. This is scientific Americans 60 second science. I'm Karen Hopkins.

They say that Marie Antoinette's hair turned white the night before she lost her head to the guillotine.

But can stress really have such a dramatic effect on hair color?

A new study in mice concludes that it can, and credits overactive nerves with stripping the color from the animal's locks and possibly ours.

Researchers at Harvard's Stem Cell Institute were interested in the stress and hair color issue.

So they decided to take a closer look at the stem cells that give rise to melanocytes,

the cells that pump pigments into each hair follicle.

The stem cells were an obvious target.

Because changes in this stem cell population

translates to changes in hair color, which are very visible and easy to identify.

Yachae Sue, the study senior author.

To start, she and her colleagues subjected mice to some rodent-sized stressors,

like having their cage tilted, their bedding dampened,

or their lights left on all night.

So what do we find?

We found that stress indeed leads

to premature hair graying in mice,

but it took a long time for us to actually narrow down how it occurs.

First, they thought it could be the immune system, attacking the melanocyte stem cell population.

However, mice lack immune cells still show premature hair grain under stress.

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