Good memory is the most recognizable sign of a healthy brain - but it's far from the only one. Neuroscience today sees the brain not as a hard drive for remembering, but as a living, changeable system that adapts to every experience. And it's in that capacity to adapt that most of what we call a "healthy mind" is hidden.

Experts list six traits a healthy brain shares, and what's interesting is that not one of them is "remembering everything." The first is adaptability - the ability to find a solution when things don't go as you imagined, instead of getting stuck. The second is curiosity that doesn't fade: learning a new language or skill builds what's called cognitive reserve, a protective layer the brain draws on later in life.

The third trait is managing emotions - not suppressing them, but the ability to feel them without being overwhelmed. The fourth is enjoying relationships with people; social bonds activate more processes in the brain at once and directly protect cognitive health. It's no cliché - loneliness harms the brain measurably.

The fifth is executive functioning: the ability to plan, to juggle multiple tasks, and to make decisions even when you don't know all the facts. The sixth, which many would overlook, is physical agility - balance, coordination, fast reaction. These depend on complex brain circuits, and when the body slows down, it's often the brain that gives the first signal.

As researcher Mara Dierssen explains, the brain is "a dynamic and plastic system that constantly changes with experience." Psychiatrist Marina Díaz Marsá adds that the brain is essential for consciousness, adaptation and interaction with the environment. The translation for the ordinary reader is encouraging: a large part of brain health isn't inherited - it's built, every day, by the choices you make.