At least one of every product in Marbles is open so shoppers can play before buying.

Some folks worry about losing their marbles. But that’s probably because they don’t realize just how easy it is to find Marbles. The toy store where your gray matter really matters opened its first D.C.-area location at Westfield Shoppingtown Montgomery last month.

To passersby, Marbles: the Brain Store (7101 Democracy Blvd., Bethesda, Md.) might look like a spot for fun and games. And it is, says CEO Lindsay Gaskins, who started the Chicago-based company in 2008 with the idea of creating a “brain gym.” People have places to exercise their bodies. “But they need to also do something about cognitive decline,” she says.

So the store is divided into five sections — critical thinking, memory, coordination, visual perception and word skills. And each item has a label explaining not just what it is and how you play with it, but also a sentence or two from a neurologist about what its benefits might be.

Take, for example, the tip for Knot So Fast ($20), which has players re-create pictures of knots: “As you think of the optimal way to generate the knots, the frontal cortex, important for critical thinking, and the parietal lobe, which monitors visual perception, are activated.”

Store employees, dubbed “brain coaches,” regularly throw around terms such as “aphasia” and “neural plasticity,” which could make the shopping experience seem like school. But because everything in the store — including party games, puzzles and Buckyballs (teeny powerful magnets) — is cracked open and available for playing on the spot, it’s more like recess.

While his girlfriend was looking at clothes last week, 27-year-old Kenton Hull escaped to sample some coordination games. After bouncing a Koosh Ball off a flexible disk, he walked over to the computers to try a brain software assessment. Then, he browsed the book selection. By the time the girlfriend wanted to leave the mall, he didn’t. “I’m a big kid,” Hull says.

Although toy stores are generally for wee ones, Marbles’ inventory is meant to appeal to all ages. Seventy-one-year-old Walter Finkelstein came in to find gifts for his grandchildren, but he was interested in doing personal shopping, too. The executive coach is a huge fan of number games. “They prevent you from going soft,” he says. Must be because they make you think so hard.

Do You Mind?

As part of Marbles’ mission to promote brain fitness, the brand developed the MindMatters program, which brings games and ideas for how to use them to older adult communities. Stores have held “neurobics” classes and crossword competitions. The first event planned at the Montgomery Mall store is a game night the third Thursday of each month (starting Oct. 20).