While driving home in a rainstorm, you learn that the bridge up ahead is washed out. What do you do? Stop where you are? Call for help? Turn back and give up? Not if you really want to get where you’re going. If it’s important enough, you find another path.
How many paths does your brain have? Our thoughts run across a massive, diverse network of synaptic pathways, with trillions of synapses that form a staggering number of possible connections. Every human brain has more potential synaptic combinations than there are atoms in the universe. Unfortunately, disease can ravage those connections. Alzheimer’s disease and other dementias are at least partially caused by plaque that accumulates in the spaces between nerve cells, inhibiting their communication. Scientists who study Alzheimer’s theorize that when important neural pathways become blocked, the brain does just what we do when we encounter an obstacle: It finds another way around.
The ability of our brains to rewire themselves in this way is an important part of what scientists call “cognitive reserve.” Put simply, cognitive reserve is the potential number of alternate routes in our brain’s atlas. People with a high amount of cognitive reserve have diverse, extensive, flexible neural networks that allow their brains to adapt and find ways around cognitive impairments. Scientists are discovering that our ability reroute our brains depends mostly on two factors: how much education we have, and how active our minds are.
A famous anecdote about cognitive reserve comes from Nick Fox, a scientist at the Institute of Neurology in London. A university professor came to his clinic because he felt his memory was slipping. Yet psychometric tests indicated he was fine, and his family found him unchanged. But the professor complained that when he played chess, he used to think nine moves ahead, and now he could only think five ahead. When the man died of an unrelated illness a few weeks later, an autopsy found his brain suffered from advanced Alzheimer’s disease. Despite this, his unusually active mind had enough reserve to buffer almost all of the manifestations of the disease.
If your thoughts always travel down the same road, you could be in trouble if, one day, that road is closed. If a person lives a routine life, isn’t challenged by his or her job, and generally does the same thing day in and day out, he or she won’t have as flexible a brain as someone who lives in a stimulating environment, challenges him or herself, is curious about the world, and keeps learning later in life.
Developing your cognitive reserve won’t prevent Alzheimer’s. But scientists have found that people with high cognitive reserve can live with the disease for years without suffering any symptoms. They believe that brains with resources will find new ways to perform necessary functions. While a person with low cognitive reserve might start having short-term memory loss within months of developing Alzheimer’s, a person with high cognitive reserve can go for five or six years before they experience any evidence of impairment.
Yaakov Stern, a neuroscientist at Columbia University, has said cognitive reserve is “as powerful as any drug we will ever have to prevent progression of Alzheimer’s disease.” But it doesn’t take a neuroscientist to understand that the benefits of cognitive reserve don’t end with prevention. People who remain curious, mentally sharp, socially active, and physically fit also get more out of life. So learn something new and build some new neurons. Give them the oxygen-rich blood needed to thrive by engaging in regular cardiovascular exercise, and feed them green vegetables, fruits with antioxidants, and fish and nuts that are rich in the omega-3 fatty acids proven to benefit the brain. You won’t just be keeping your memory sharp — you’ll be embracing life.